ViewVC Help

View File | Revision Log | Show Annotations | Download File | Root Listing

root/jsr166/jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java

Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.15 by tim, Wed Aug 6 18:22:09 2003 UTC vs.
Revision 1.317 by jsr166, Sat Jul 27 17:47:05 2019 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. Use, modify, and
4	<	* redistribute this code in any way without acknowledgement.
3	>	* Expert Group and released to the public domain, as explained at
4	>	* http://creativecommons.org/publicdomain/zero/1.0/
5		*/
6
7		package java.util.concurrent;
8	<	import java.util.concurrent.locks.*;
9	<	import java.util.*;
8	>
9	>	import java.io.ObjectStreamField;
10		import java.io.Serializable;
11	<	import java.io.IOException;
12	<	import java.io.ObjectInputStream;
13	<	import java.io.ObjectOutputStream;
11	>	import java.lang.reflect.ParameterizedType;
12	>	import java.lang.reflect.Type;
13	>	import java.util.AbstractMap;
14	>	import java.util.Arrays;
15	>	import java.util.Collection;
16	>	import java.util.Enumeration;
17	>	import java.util.HashMap;
18	>	import java.util.Hashtable;
19	>	import java.util.Iterator;
20	>	import java.util.Map;
21	>	import java.util.NoSuchElementException;
22	>	import java.util.Set;
23	>	import java.util.Spliterator;
24	>	import java.util.concurrent.atomic.AtomicReference;
25	>	import java.util.concurrent.locks.LockSupport;
26	>	import java.util.concurrent.locks.ReentrantLock;
27	>	import java.util.function.BiConsumer;
28	>	import java.util.function.BiFunction;
29	>	import java.util.function.Consumer;
30	>	import java.util.function.DoubleBinaryOperator;
31	>	import java.util.function.Function;
32	>	import java.util.function.IntBinaryOperator;
33	>	import java.util.function.LongBinaryOperator;
34	>	import java.util.function.Predicate;
35	>	import java.util.function.ToDoubleBiFunction;
36	>	import java.util.function.ToDoubleFunction;
37	>	import java.util.function.ToIntBiFunction;
38	>	import java.util.function.ToIntFunction;
39	>	import java.util.function.ToLongBiFunction;
40	>	import java.util.function.ToLongFunction;
41	>	import java.util.stream.Stream;
42	>	import jdk.internal.misc.Unsafe;
43
44		/**
45		* A hash table supporting full concurrency of retrievals and
46	<	* adjustable expected concurrency for updates. This class obeys the
47	<	* same functional specification as
48	<	* <tt>java.util.Hashtable</tt>. However, even though all operations
49	<	* are thread-safe, retrieval operations do <em>not</em> entail
50	<	* locking, and there is <em>not</em> any support for locking the
51	<	* entire table in a way that prevents all access.  This class is
52	<	* fully interoperable with Hashtable in programs that rely on its
46	>	* high expected concurrency for updates. This class obeys the
47	>	* same functional specification as {@link java.util.Hashtable}, and
48	>	* includes versions of methods corresponding to each method of
49	>	* {@code Hashtable}. However, even though all operations are
50	>	* thread-safe, retrieval operations do <em>not</em> entail locking,
51	>	* and there is <em>not</em> any support for locking the entire table
52	>	* in a way that prevents all access.  This class is fully
53	>	* interoperable with {@code Hashtable} in programs that rely on its
54		* thread safety but not on its synchronization details.
55		*
56	<	* <p> Retrieval operations (including <tt>get</tt>) ordinarily
57	<	* overlap with update operations (including <tt>put</tt> and
58	<	* <tt>remove</tt>). Retrievals reflect the results of the most
56	>	* <p>Retrieval operations (including {@code get}) generally do not
57	>	* block, so may overlap with update operations (including {@code put}
58	>	* and {@code remove}). Retrievals reflect the results of the most
59		* recently <em>completed</em> update operations holding upon their
60	<	* onset.  For aggregate operations such as <tt>putAll</tt> and
61	<	* <tt>clear</tt>, concurrent retrievals may reflect insertion or
62	<	* removal of only some entries.  Similarly, Iterators and
63	<	* Enumerations return elements reflecting the state of the hash table
64	<	* at some point at or since the creation of the iterator/enumeration.
65	<	* They do <em>not</em> throw ConcurrentModificationException.
66	<	* However, Iterators are designed to be used by only one thread at a
67	<	* time.
68	<	*
69	<	* <p> The allowed concurrency among update operations is controlled
70	<	* by the optional <tt>segments</tt> constructor argument (default
71	<	* 16). The table is divided into this many independent parts, each of
72	<	* which can be updated concurrently. Because placement in hash tables
73	<	* is essentially random, the actual concurrency will vary. As a rough
74	<	* rule of thumb, you should choose at least as many segments as you
75	<	* expect concurrent threads. However, using more segments than you
76	<	* need can waste space and time. Using a value of 1 for
77	<	* <tt>segments</tt> results in a table that is concurrently readable
78	<	* but can only be updated by one thread at a time.
60	>	* onset. (More formally, an update operation for a given key bears a
61	>	* <em>happens-before</em> relation with any (non-null) retrieval for
62	>	* that key reporting the updated value.)  For aggregate operations
63	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
64	>	* reflect insertion or removal of only some entries.  Similarly,
65	>	* Iterators, Spliterators and Enumerations return elements reflecting the
66	>	* state of the hash table at some point at or since the creation of the
67	>	* iterator/enumeration.  They do <em>not</em> throw {@link
68	>	* java.util.ConcurrentModificationException ConcurrentModificationException}.
69	>	* However, iterators are designed to be used by only one thread at a time.
70	>	* Bear in mind that the results of aggregate status methods including
71	>	* {@code size}, {@code isEmpty}, and {@code containsValue} are typically
72	>	* useful only when a map is not undergoing concurrent updates in other threads.
73	>	* Otherwise the results of these methods reflect transient states
74	>	* that may be adequate for monitoring or estimation purposes, but not
75	>	* for program control.
76	>	*
77	>	* <p>The table is dynamically expanded when there are too many
78	>	* collisions (i.e., keys that have distinct hash codes but fall into
79	>	* the same slot modulo the table size), with the expected average
80	>	* effect of maintaining roughly two bins per mapping (corresponding
81	>	* to a 0.75 load factor threshold for resizing). There may be much
82	>	* variance around this average as mappings are added and removed, but
83	>	* overall, this maintains a commonly accepted time/space tradeoff for
84	>	* hash tables.  However, resizing this or any other kind of hash
85	>	* table may be a relatively slow operation. When possible, it is a
86	>	* good idea to provide a size estimate as an optional {@code
87	>	* initialCapacity} constructor argument. An additional optional
88	>	* {@code loadFactor} constructor argument provides a further means of
89	>	* customizing initial table capacity by specifying the table density
90	>	* to be used in calculating the amount of space to allocate for the
91	>	* given number of elements.  Also, for compatibility with previous
92	>	* versions of this class, constructors may optionally specify an
93	>	* expected {@code concurrencyLevel} as an additional hint for
94	>	* internal sizing.  Note that using many keys with exactly the same
95	>	* {@code hashCode()} is a sure way to slow down performance of any
96	>	* hash table. To ameliorate impact, when keys are {@link Comparable},
97	>	* this class may use comparison order among keys to help break ties.
98	>	*
99	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
100	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
101	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
102	>	* mapped values are (perhaps transiently) not used or all take the
103	>	* same mapping value.
104	>	*
105	>	* <p>A ConcurrentHashMap can be used as a scalable frequency map (a
106	>	* form of histogram or multiset) by using {@link
107	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
108	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
109	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
110	>	* {@code freqs.computeIfAbsent(key, k -> new LongAdder()).increment();}
111	>	*
112	>	* <p>This class and its views and iterators implement all of the
113	>	* <em>optional</em> methods of the {@link Map} and {@link Iterator}
114	>	* interfaces.
115	>	*
116	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
117	>	* does <em>not</em> allow {@code null} to be used as a key or value.
118	>	*
119	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
120	>	* operations that, unlike most {@link Stream} methods, are designed
121	>	* to be safely, and often sensibly, applied even with maps that are
122	>	* being concurrently updated by other threads; for example, when
123	>	* computing a snapshot summary of the values in a shared registry.
124	>	* There are three kinds of operation, each with four forms, accepting
125	>	* functions with keys, values, entries, and (key, value) pairs as
126	>	* arguments and/or return values. Because the elements of a
127	>	* ConcurrentHashMap are not ordered in any particular way, and may be
128	>	* processed in different orders in different parallel executions, the
129	>	* correctness of supplied functions should not depend on any
130	>	* ordering, or on any other objects or values that may transiently
131	>	* change while computation is in progress; and except for forEach
132	>	* actions, should ideally be side-effect-free. Bulk operations on
133	>	* {@link Map.Entry} objects do not support method {@code setValue}.
134	>	*
135	>	* <ul>
136	>	* <li>forEach: Performs a given action on each element.
137	>	* A variant form applies a given transformation on each element
138	>	* before performing the action.
139	>	*
140	>	* <li>search: Returns the first available non-null result of
141	>	* applying a given function on each element; skipping further
142	>	* search when a result is found.
143	>	*
144	>	* <li>reduce: Accumulates each element.  The supplied reduction
145	>	* function cannot rely on ordering (more formally, it should be
146	>	* both associative and commutative).  There are five variants:
147	>	*
148	>	* <ul>
149	>	*
150	>	* <li>Plain reductions. (There is not a form of this method for
151	>	* (key, value) function arguments since there is no corresponding
152	>	* return type.)
153	>	*
154	>	* <li>Mapped reductions that accumulate the results of a given
155	>	* function applied to each element.
156	>	*
157	>	* <li>Reductions to scalar doubles, longs, and ints, using a
158	>	* given basis value.
159	>	*
160	>	* </ul>
161	>	* </ul>
162	>	*
163	>	* <p>These bulk operations accept a {@code parallelismThreshold}
164	>	* argument. Methods proceed sequentially if the current map size is
165	>	* estimated to be less than the given threshold. Using a value of
166	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
167	>	* of {@code 1} results in maximal parallelism by partitioning into
168	>	* enough subtasks to fully utilize the {@link
169	>	* ForkJoinPool#commonPool()} that is used for all parallel
170	>	* computations. Normally, you would initially choose one of these
171	>	* extreme values, and then measure performance of using in-between
172	>	* values that trade off overhead versus throughput.
173	>	*
174	>	* <p>The concurrency properties of bulk operations follow
175	>	* from those of ConcurrentHashMap: Any non-null result returned
176	>	* from {@code get(key)} and related access methods bears a
177	>	* happens-before relation with the associated insertion or
178	>	* update.  The result of any bulk operation reflects the
179	>	* composition of these per-element relations (but is not
180	>	* necessarily atomic with respect to the map as a whole unless it
181	>	* is somehow known to be quiescent).  Conversely, because keys
182	>	* and values in the map are never null, null serves as a reliable
183	>	* atomic indicator of the current lack of any result.  To
184	>	* maintain this property, null serves as an implicit basis for
185	>	* all non-scalar reduction operations. For the double, long, and
186	>	* int versions, the basis should be one that, when combined with
187	>	* any other value, returns that other value (more formally, it
188	>	* should be the identity element for the reduction). Most common
189	>	* reductions have these properties; for example, computing a sum
190	>	* with basis 0 or a minimum with basis MAX_VALUE.
191	>	*
192	>	* <p>Search and transformation functions provided as arguments
193	>	* should similarly return null to indicate the lack of any result
194	>	* (in which case it is not used). In the case of mapped
195	>	* reductions, this also enables transformations to serve as
196	>	* filters, returning null (or, in the case of primitive
197	>	* specializations, the identity basis) if the element should not
198	>	* be combined. You can create compound transformations and
199	>	* filterings by composing them yourself under this "null means
200	>	* there is nothing there now" rule before using them in search or
201	>	* reduce operations.
202	>	*
203	>	* <p>Methods accepting and/or returning Entry arguments maintain
204	>	* key-value associations. They may be useful for example when
205	>	* finding the key for the greatest value. Note that "plain" Entry
206	>	* arguments can be supplied using {@code new
207	>	* AbstractMap.SimpleEntry(k,v)}.
208	>	*
209	>	* <p>Bulk operations may complete abruptly, throwing an
210	>	* exception encountered in the application of a supplied
211	>	* function. Bear in mind when handling such exceptions that other
212	>	* concurrently executing functions could also have thrown
213	>	* exceptions, or would have done so if the first exception had
214	>	* not occurred.
215	>	*
216	>	* <p>Speedups for parallel compared to sequential forms are common
217	>	* but not guaranteed.  Parallel operations involving brief functions
218	>	* on small maps may execute more slowly than sequential forms if the
219	>	* underlying work to parallelize the computation is more expensive
220	>	* than the computation itself.  Similarly, parallelization may not
221	>	* lead to much actual parallelism if all processors are busy
222	>	* performing unrelated tasks.
223	>	*
224	>	* <p>All arguments to all task methods must be non-null.
225		*
226	<	* <p> Like Hashtable but unlike java.util.HashMap, this class does
227	<	* NOT allow <tt>null</tt> to be used as a key or value.
226	>	* <p>This class is a member of the
227	>	* <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework">
228	>	* Java Collections Framework</a>.
229		*
230		* @since 1.5
231		* @author Doug Lea
232	+	* @param <K> the type of keys maintained by this map
233	+	* @param <V> the type of mapped values
234		*/
235	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
236	<	implements ConcurrentMap<K, V>, Cloneable, Serializable {
235	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
236	>	implements ConcurrentMap<K,V>, Serializable {
237	>	private static final long serialVersionUID = 7249069246763182397L;
238
239		/*
240	<	* The basic strategy is to subdivide the table among Segments,
241	<	* each of which itself is a concurrently readable hash table.
240	>	* Overview:
241	>	*
242	>	* The primary design goal of this hash table is to maintain
243	>	* concurrent readability (typically method get(), but also
244	>	* iterators and related methods) while minimizing update
245	>	* contention. Secondary goals are to keep space consumption about
246	>	* the same or better than java.util.HashMap, and to support high
247	>	* initial insertion rates on an empty table by many threads.
248	>	*
249	>	* This map usually acts as a binned (bucketed) hash table.  Each
250	>	* key-value mapping is held in a Node.  Most nodes are instances
251	>	* of the basic Node class with hash, key, value, and next
252	>	* fields. However, various subclasses exist: TreeNodes are
253	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
254	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
255	>	* of bins during resizing. ReservationNodes are used as
256	>	* placeholders while establishing values in computeIfAbsent and
257	>	* related methods.  The types TreeBin, ForwardingNode, and
258	>	* ReservationNode do not hold normal user keys, values, or
259	>	* hashes, and are readily distinguishable during search etc
260	>	* because they have negative hash fields and null key and value
261	>	* fields. (These special nodes are either uncommon or transient,
262	>	* so the impact of carrying around some unused fields is
263	>	* insignificant.)
264	>	*
265	>	* The table is lazily initialized to a power-of-two size upon the
266	>	* first insertion.  Each bin in the table normally contains a
267	>	* list of Nodes (most often, the list has only zero or one Node).
268	>	* Table accesses require volatile/atomic reads, writes, and
269	>	* CASes.  Because there is no other way to arrange this without
270	>	* adding further indirections, we use intrinsics
271	>	* (jdk.internal.misc.Unsafe) operations.
272	>	*
273	>	* We use the top (sign) bit of Node hash fields for control
274	>	* purposes -- it is available anyway because of addressing
275	>	* constraints.  Nodes with negative hash fields are specially
276	>	* handled or ignored in map methods.
277	>	*
278	>	* Insertion (via put or its variants) of the first node in an
279	>	* empty bin is performed by just CASing it to the bin.  This is
280	>	* by far the most common case for put operations under most
281	>	* key/hash distributions.  Other update operations (insert,
282	>	* delete, and replace) require locks.  We do not want to waste
283	>	* the space required to associate a distinct lock object with
284	>	* each bin, so instead use the first node of a bin list itself as
285	>	* a lock. Locking support for these locks relies on builtin
286	>	* "synchronized" monitors.
287	>	*
288	>	* Using the first node of a list as a lock does not by itself
289	>	* suffice though: When a node is locked, any update must first
290	>	* validate that it is still the first node after locking it, and
291	>	* retry if not. Because new nodes are always appended to lists,
292	>	* once a node is first in a bin, it remains first until deleted
293	>	* or the bin becomes invalidated (upon resizing).
294	>	*
295	>	* The main disadvantage of per-bin locks is that other update
296	>	* operations on other nodes in a bin list protected by the same
297	>	* lock can stall, for example when user equals() or mapping
298	>	* functions take a long time.  However, statistically, under
299	>	* random hash codes, this is not a common problem.  Ideally, the
300	>	* frequency of nodes in bins follows a Poisson distribution
301	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
302	>	* parameter of about 0.5 on average, given the resizing threshold
303	>	* of 0.75, although with a large variance because of resizing
304	>	* granularity. Ignoring variance, the expected occurrences of
305	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
306	>	* first values are:
307	>	*
308	>	* 0:    0.60653066
309	>	* 1:    0.30326533
310	>	* 2:    0.07581633
311	>	* 3:    0.01263606
312	>	* 4:    0.00157952
313	>	* 5:    0.00015795
314	>	* 6:    0.00001316
315	>	* 7:    0.00000094
316	>	* 8:    0.00000006
317	>	* more: less than 1 in ten million
318	>	*
319	>	* Lock contention probability for two threads accessing distinct
320	>	* elements is roughly 1 / (8 * #elements) under random hashes.
321	>	*
322	>	* Actual hash code distributions encountered in practice
323	>	* sometimes deviate significantly from uniform randomness.  This
324	>	* includes the case when N > (1<<30), so some keys MUST collide.
325	>	* Similarly for dumb or hostile usages in which multiple keys are
326	>	* designed to have identical hash codes or ones that differs only
327	>	* in masked-out high bits. So we use a secondary strategy that
328	>	* applies when the number of nodes in a bin exceeds a
329	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
330	>	* specialized form of red-black trees), bounding search time to
331	>	* O(log N).  Each search step in a TreeBin is at least twice as
332	>	* slow as in a regular list, but given that N cannot exceed
333	>	* (1<<64) (before running out of addresses) this bounds search
334	>	* steps, lock hold times, etc, to reasonable constants (roughly
335	>	* 100 nodes inspected per operation worst case) so long as keys
336	>	* are Comparable (which is very common -- String, Long, etc).
337	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
338	>	* traversal pointers as regular nodes, so can be traversed in
339	>	* iterators in the same way.
340	>	*
341	>	* The table is resized when occupancy exceeds a percentage
342	>	* threshold (nominally, 0.75, but see below).  Any thread
343	>	* noticing an overfull bin may assist in resizing after the
344	>	* initiating thread allocates and sets up the replacement array.
345	>	* However, rather than stalling, these other threads may proceed
346	>	* with insertions etc.  The use of TreeBins shields us from the
347	>	* worst case effects of overfilling while resizes are in
348	>	* progress.  Resizing proceeds by transferring bins, one by one,
349	>	* from the table to the next table. However, threads claim small
350	>	* blocks of indices to transfer (via field transferIndex) before
351	>	* doing so, reducing contention.  A generation stamp in field
352	>	* sizeCtl ensures that resizings do not overlap. Because we are
353	>	* using power-of-two expansion, the elements from each bin must
354	>	* either stay at same index, or move with a power of two
355	>	* offset. We eliminate unnecessary node creation by catching
356	>	* cases where old nodes can be reused because their next fields
357	>	* won't change.  On average, only about one-sixth of them need
358	>	* cloning when a table doubles. The nodes they replace will be
359	>	* garbage collectible as soon as they are no longer referenced by
360	>	* any reader thread that may be in the midst of concurrently
361	>	* traversing table.  Upon transfer, the old table bin contains
362	>	* only a special forwarding node (with hash field "MOVED") that
363	>	* contains the next table as its key. On encountering a
364	>	* forwarding node, access and update operations restart, using
365	>	* the new table.
366	>	*
367	>	* Each bin transfer requires its bin lock, which can stall
368	>	* waiting for locks while resizing. However, because other
369	>	* threads can join in and help resize rather than contend for
370	>	* locks, average aggregate waits become shorter as resizing
371	>	* progresses.  The transfer operation must also ensure that all
372	>	* accessible bins in both the old and new table are usable by any
373	>	* traversal.  This is arranged in part by proceeding from the
374	>	* last bin (table.length - 1) up towards the first.  Upon seeing
375	>	* a forwarding node, traversals (see class Traverser) arrange to
376	>	* move to the new table without revisiting nodes.  To ensure that
377	>	* no intervening nodes are skipped even when moved out of order,
378	>	* a stack (see class TableStack) is created on first encounter of
379	>	* a forwarding node during a traversal, to maintain its place if
380	>	* later processing the current table. The need for these
381	>	* save/restore mechanics is relatively rare, but when one
382	>	* forwarding node is encountered, typically many more will be.
383	>	* So Traversers use a simple caching scheme to avoid creating so
384	>	* many new TableStack nodes. (Thanks to Peter Levart for
385	>	* suggesting use of a stack here.)
386	>	*
387	>	* The traversal scheme also applies to partial traversals of
388	>	* ranges of bins (via an alternate Traverser constructor)
389	>	* to support partitioned aggregate operations.  Also, read-only
390	>	* operations give up if ever forwarded to a null table, which
391	>	* provides support for shutdown-style clearing, which is also not
392	>	* currently implemented.
393	>	*
394	>	* Lazy table initialization minimizes footprint until first use,
395	>	* and also avoids resizings when the first operation is from a
396	>	* putAll, constructor with map argument, or deserialization.
397	>	* These cases attempt to override the initial capacity settings,
398	>	* but harmlessly fail to take effect in cases of races.
399	>	*
400	>	* The element count is maintained using a specialization of
401	>	* LongAdder. We need to incorporate a specialization rather than
402	>	* just use a LongAdder in order to access implicit
403	>	* contention-sensing that leads to creation of multiple
404	>	* CounterCells.  The counter mechanics avoid contention on
405	>	* updates but can encounter cache thrashing if read too
406	>	* frequently during concurrent access. To avoid reading so often,
407	>	* resizing under contention is attempted only upon adding to a
408	>	* bin already holding two or more nodes. Under uniform hash
409	>	* distributions, the probability of this occurring at threshold
410	>	* is around 13%, meaning that only about 1 in 8 puts check
411	>	* threshold (and after resizing, many fewer do so).
412	>	*
413	>	* TreeBins use a special form of comparison for search and
414	>	* related operations (which is the main reason we cannot use
415	>	* existing collections such as TreeMaps). TreeBins contain
416	>	* Comparable elements, but may contain others, as well as
417	>	* elements that are Comparable but not necessarily Comparable for
418	>	* the same T, so we cannot invoke compareTo among them. To handle
419	>	* this, the tree is ordered primarily by hash value, then by
420	>	* Comparable.compareTo order if applicable.  On lookup at a node,
421	>	* if elements are not comparable or compare as 0 then both left
422	>	* and right children may need to be searched in the case of tied
423	>	* hash values. (This corresponds to the full list search that
424	>	* would be necessary if all elements were non-Comparable and had
425	>	* tied hashes.) On insertion, to keep a total ordering (or as
426	>	* close as is required here) across rebalancings, we compare
427	>	* classes and identityHashCodes as tie-breakers. The red-black
428	>	* balancing code is updated from pre-jdk-collections
429	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
430	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
431	>	* Algorithms" (CLR).
432	>	*
433	>	* TreeBins also require an additional locking mechanism.  While
434	>	* list traversal is always possible by readers even during
435	>	* updates, tree traversal is not, mainly because of tree-rotations
436	>	* that may change the root node and/or its linkages.  TreeBins
437	>	* include a simple read-write lock mechanism parasitic on the
438	>	* main bin-synchronization strategy: Structural adjustments
439	>	* associated with an insertion or removal are already bin-locked
440	>	* (and so cannot conflict with other writers) but must wait for
441	>	* ongoing readers to finish. Since there can be only one such
442	>	* waiter, we use a simple scheme using a single "waiter" field to
443	>	* block writers.  However, readers need never block.  If the root
444	>	* lock is held, they proceed along the slow traversal path (via
445	>	* next-pointers) until the lock becomes available or the list is
446	>	* exhausted, whichever comes first. These cases are not fast, but
447	>	* maximize aggregate expected throughput.
448	>	*
449	>	* Maintaining API and serialization compatibility with previous
450	>	* versions of this class introduces several oddities. Mainly: We
451	>	* leave untouched but unused constructor arguments referring to
452	>	* concurrencyLevel. We accept a loadFactor constructor argument,
453	>	* but apply it only to initial table capacity (which is the only
454	>	* time that we can guarantee to honor it.) We also declare an
455	>	* unused "Segment" class that is instantiated in minimal form
456	>	* only when serializing.
457	>	*
458	>	* Also, solely for compatibility with previous versions of this
459	>	* class, it extends AbstractMap, even though all of its methods
460	>	* are overridden, so it is just useless baggage.
461	>	*
462	>	* This file is organized to make things a little easier to follow
463	>	* while reading than they might otherwise: First the main static
464	>	* declarations and utilities, then fields, then main public
465	>	* methods (with a few factorings of multiple public methods into
466	>	* internal ones), then sizing methods, trees, traversers, and
467	>	* bulk operations.
468		*/
469
470		/* ---------------- Constants -------------- */
471
472		/**
473	<	* The default initial number of table slots for this table (32).
474	<	* Used when not otherwise specified in constructor.
473	>	* The largest possible table capacity.  This value must be
474	>	* exactly 1<<30 to stay within Java array allocation and indexing
475	>	* bounds for power of two table sizes, and is further required
476	>	* because the top two bits of 32bit hash fields are used for
477	>	* control purposes.
478	>	*/
479	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
480	>
481	>	/**
482	>	* The default initial table capacity.  Must be a power of 2
483	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
484	>	*/
485	>	private static final int DEFAULT_CAPACITY = 16;
486	>
487	>	/**
488	>	* The largest possible (non-power of two) array size.
489	>	* Needed by toArray and related methods.
490	>	*/
491	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
492	>
493	>	/**
494	>	* The default concurrency level for this table. Unused but
495	>	* defined for compatibility with previous versions of this class.
496	>	*/
497	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
498	>
499	>	/**
500	>	* The load factor for this table. Overrides of this value in
501	>	* constructors affect only the initial table capacity.  The
502	>	* actual floating point value isn't normally used -- it is
503	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
504	>	* the associated resizing threshold.
505	>	*/
506	>	private static final float LOAD_FACTOR = 0.75f;
507	>
508	>	/**
509	>	* The bin count threshold for using a tree rather than list for a
510	>	* bin.  Bins are converted to trees when adding an element to a
511	>	* bin with at least this many nodes. The value must be greater
512	>	* than 2, and should be at least 8 to mesh with assumptions in
513	>	* tree removal about conversion back to plain bins upon
514	>	* shrinkage.
515	>	*/
516	>	static final int TREEIFY_THRESHOLD = 8;
517	>
518	>	/**
519	>	* The bin count threshold for untreeifying a (split) bin during a
520	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
521	>	* most 6 to mesh with shrinkage detection under removal.
522	>	*/
523	>	static final int UNTREEIFY_THRESHOLD = 6;
524	>
525	>	/**
526	>	* The smallest table capacity for which bins may be treeified.
527	>	* (Otherwise the table is resized if too many nodes in a bin.)
528	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
529	>	* conflicts between resizing and treeification thresholds.
530	>	*/
531	>	static final int MIN_TREEIFY_CAPACITY = 64;
532	>
533	>	/**
534	>	* Minimum number of rebinnings per transfer step. Ranges are
535	>	* subdivided to allow multiple resizer threads.  This value
536	>	* serves as a lower bound to avoid resizers encountering
537	>	* excessive memory contention.  The value should be at least
538	>	* DEFAULT_CAPACITY.
539	>	*/
540	>	private static final int MIN_TRANSFER_STRIDE = 16;
541	>
542	>	/**
543	>	* The number of bits used for generation stamp in sizeCtl.
544	>	* Must be at least 6 for 32bit arrays.
545	>	*/
546	>	private static final int RESIZE_STAMP_BITS = 16;
547	>
548	>	/**
549	>	* The maximum number of threads that can help resize.
550	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
551	>	*/
552	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
553	>
554	>	/**
555	>	* The bit shift for recording size stamp in sizeCtl.
556	>	*/
557	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
558	>
559	>	/*
560	>	* Encodings for Node hash fields. See above for explanation.
561	>	*/
562	>	static final int MOVED     = -1; // hash for forwarding nodes
563	>	static final int TREEBIN   = -2; // hash for roots of trees
564	>	static final int RESERVED  = -3; // hash for transient reservations
565	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
566	>
567	>	/** Number of CPUS, to place bounds on some sizings */
568	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
569	>
570	>	/**
571	>	* Serialized pseudo-fields, provided only for jdk7 compatibility.
572	>	* @serialField segments Segment[]
573	>	*   The segments, each of which is a specialized hash table.
574	>	* @serialField segmentMask int
575	>	*   Mask value for indexing into segments. The upper bits of a
576	>	*   key's hash code are used to choose the segment.
577	>	* @serialField segmentShift int
578	>	*   Shift value for indexing within segments.
579	>	*/
580	>	private static final ObjectStreamField[] serialPersistentFields = {
581	>	new ObjectStreamField("segments", Segment[].class),
582	>	new ObjectStreamField("segmentMask", Integer.TYPE),
583	>	new ObjectStreamField("segmentShift", Integer.TYPE),
584	>	};
585	>
586	>	/* ---------------- Nodes -------------- */
587	>
588	>	/**
589	>	* Key-value entry.  This class is never exported out as a
590	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
591	>	* MapEntry below), but can be used for read-only traversals used
592	>	* in bulk tasks.  Subclasses of Node with a negative hash field
593	>	* are special, and contain null keys and values (but are never
594	>	* exported).  Otherwise, keys and vals are never null.
595	>	*/
596	>	static class Node<K,V> implements Map.Entry<K,V> {
597	>	final int hash;
598	>	final K key;
599	>	volatile V val;
600	>	volatile Node<K,V> next;
601	>
602	>	Node(int hash, K key, V val) {
603	>	this.hash = hash;
604	>	this.key = key;
605	>	this.val = val;
606	>	}
607	>
608	>	Node(int hash, K key, V val, Node<K,V> next) {
609	>	this(hash, key, val);
610	>	this.next = next;
611	>	}
612	>
613	>	public final K getKey()     { return key; }
614	>	public final V getValue()   { return val; }
615	>	public final int hashCode() { return key.hashCode() ^ val.hashCode(); }
616	>	public final String toString() {
617	>	return Helpers.mapEntryToString(key, val);
618	>	}
619	>	public final V setValue(V value) {
620	>	throw new UnsupportedOperationException();
621	>	}
622	>
623	>	public final boolean equals(Object o) {
624	>	Object k, v, u; Map.Entry<?,?> e;
625	>	return ((o instanceof Map.Entry) &&
626	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
627	>	(v = e.getValue()) != null &&
628	>	(k == key || k.equals(key)) &&
629	>	(v == (u = val) || v.equals(u)));
630	>	}
631	>
632	>	/**
633	>	* Virtualized support for map.get(); overridden in subclasses.
634	>	*/
635	>	Node<K,V> find(int h, Object k) {
636	>	Node<K,V> e = this;
637	>	if (k != null) {
638	>	do {
639	>	K ek;
640	>	if (e.hash == h &&
641	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
642	>	return e;
643	>	} while ((e = e.next) != null);
644	>	}
645	>	return null;
646	>	}
647	>	}
648	>
649	>	/* ---------------- Static utilities -------------- */
650	>
651	>	/**
652	>	* Spreads (XORs) higher bits of hash to lower and also forces top
653	>	* bit to 0. Because the table uses power-of-two masking, sets of
654	>	* hashes that vary only in bits above the current mask will
655	>	* always collide. (Among known examples are sets of Float keys
656	>	* holding consecutive whole numbers in small tables.)  So we
657	>	* apply a transform that spreads the impact of higher bits
658	>	* downward. There is a tradeoff between speed, utility, and
659	>	* quality of bit-spreading. Because many common sets of hashes
660	>	* are already reasonably distributed (so don't benefit from
661	>	* spreading), and because we use trees to handle large sets of
662	>	* collisions in bins, we just XOR some shifted bits in the
663	>	* cheapest possible way to reduce systematic lossage, as well as
664	>	* to incorporate impact of the highest bits that would otherwise
665	>	* never be used in index calculations because of table bounds.
666		*/
667	<	private static int DEFAULT_INITIAL_CAPACITY = 16;
667	>	static final int spread(int h) {
668	>	return (h ^ (h >>> 16)) & HASH_BITS;
669	>	}
670
671		/**
672	<	* The maximum capacity, used if a higher value is implicitly
673	<	* specified by either of the constructors with arguments.  MUST
75	<	* be a power of two <= 1<<30.
672	>	* Returns a power of two table size for the given desired capacity.
673	>	* See Hackers Delight, sec 3.2
674		*/
675	<	static final int MAXIMUM_CAPACITY = 1 << 30;
675	>	private static final int tableSizeFor(int c) {
676	>	int n = -1 >>> Integer.numberOfLeadingZeros(c - 1);
677	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
678	>	}
679
680		/**
681	<	* The default load factor for this table.  Used when not
682	<	* otherwise specified in constructor.
681	>	* Returns x's Class if it is of the form "class C implements
682	>	* Comparable<C>", else null.
683		*/
684	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
684	>	static Class<?> comparableClassFor(Object x) {
685	>	if (x instanceof Comparable) {
686	>	Class<?> c; Type[] ts, as; ParameterizedType p;
687	>	if ((c = x.getClass()) == String.class) // bypass checks
688	>	return c;
689	>	if ((ts = c.getGenericInterfaces()) != null) {
690	>	for (Type t : ts) {
691	>	if ((t instanceof ParameterizedType) &&
692	>	((p = (ParameterizedType)t).getRawType() ==
693	>	Comparable.class) &&
694	>	(as = p.getActualTypeArguments()) != null &&
695	>	as.length == 1 && as[0] == c) // type arg is c
696	>	return c;
697	>	}
698	>	}
699	>	}
700	>	return null;
701	>	}
702
703		/**
704	<	* The default number of concurrency control segments.
705	<	**/
706	<	private static final int DEFAULT_SEGMENTS = 16;
704	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
705	>	* class), else 0.
706	>	*/
707	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
708	>	static int compareComparables(Class<?> kc, Object k, Object x) {
709	>	return (x == null || x.getClass() != kc ? 0 :
710	>	((Comparable)k).compareTo(x));
711	>	}
712	>
713	>	/* ---------------- Table element access -------------- */
714	>
715	>	/*
716	>	* Atomic access methods are used for table elements as well as
717	>	* elements of in-progress next table while resizing.  All uses of
718	>	* the tab arguments must be null checked by callers.  All callers
719	>	* also paranoically precheck that tab's length is not zero (or an
720	>	* equivalent check), thus ensuring that any index argument taking
721	>	* the form of a hash value anded with (length - 1) is a valid
722	>	* index.  Note that, to be correct wrt arbitrary concurrency
723	>	* errors by users, these checks must operate on local variables,
724	>	* which accounts for some odd-looking inline assignments below.
725	>	* Note that calls to setTabAt always occur within locked regions,
726	>	* and so require only release ordering.
727	>	*/
728	>
729	>	@SuppressWarnings("unchecked")
730	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
731	>	return (Node<K,V>)U.getObjectAcquire(tab, ((long)i << ASHIFT) + ABASE);
732	>	}
733	>
734	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
735	>	Node<K,V> c, Node<K,V> v) {
736	>	return U.compareAndSetObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
737	>	}
738	>
739	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
740	>	U.putObjectRelease(tab, ((long)i << ASHIFT) + ABASE, v);
741	>	}
742
743		/* ---------------- Fields -------------- */
744
745		/**
746	<	* Mask value for indexing into segments. The upper bits of a
747	<	* key's hash code are used to choose the segment.
748	<	**/
749	<	private final int segmentMask;
746	>	* The array of bins. Lazily initialized upon first insertion.
747	>	* Size is always a power of two. Accessed directly by iterators.
748	>	*/
749	>	transient volatile Node<K,V>[] table;
750	>
751	>	/**
752	>	* The next table to use; non-null only while resizing.
753	>	*/
754	>	private transient volatile Node<K,V>[] nextTable;
755	>
756	>	/**
757	>	* Base counter value, used mainly when there is no contention,
758	>	* but also as a fallback during table initialization
759	>	* races. Updated via CAS.
760	>	*/
761	>	private transient volatile long baseCount;
762	>
763	>	/**
764	>	* Table initialization and resizing control.  When negative, the
765	>	* table is being initialized or resized: -1 for initialization,
766	>	* else -(1 + the number of active resizing threads).  Otherwise,
767	>	* when table is null, holds the initial table size to use upon
768	>	* creation, or 0 for default. After initialization, holds the
769	>	* next element count value upon which to resize the table.
770	>	*/
771	>	private transient volatile int sizeCtl;
772	>
773	>	/**
774	>	* The next table index (plus one) to split while resizing.
775	>	*/
776	>	private transient volatile int transferIndex;
777	>
778	>	/**
779	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
780	>	*/
781	>	private transient volatile int cellsBusy;
782	>
783	>	/**
784	>	* Table of counter cells. When non-null, size is a power of 2.
785	>	*/
786	>	private transient volatile CounterCell[] counterCells;
787	>
788	>	// views
789	>	private transient KeySetView<K,V> keySet;
790	>	private transient ValuesView<K,V> values;
791	>	private transient EntrySetView<K,V> entrySet;
792	>
793	>
794	>	/* ---------------- Public operations -------------- */
795	>
796	>	/**
797	>	* Creates a new, empty map with the default initial table size (16).
798	>	*/
799	>	public ConcurrentHashMap() {
800	>	}
801	>
802	>	/**
803	>	* Creates a new, empty map with an initial table size
804	>	* accommodating the specified number of elements without the need
805	>	* to dynamically resize.
806	>	*
807	>	* @param initialCapacity The implementation performs internal
808	>	* sizing to accommodate this many elements.
809	>	* @throws IllegalArgumentException if the initial capacity of
810	>	* elements is negative
811	>	*/
812	>	public ConcurrentHashMap(int initialCapacity) {
813	>	this(initialCapacity, LOAD_FACTOR, 1);
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}), initial
848	>	* table 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	>	/**
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	>	/** 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; K fk; V fv;
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, new Node<K,V>(hash, key, value)))
991	>	break;                   // no lock when adding to empty bin
992	>	}
993	>	else if ((fh = f.hash) == MOVED)
994	>	tab = helpTransfer(tab, f);
995	>	else if (onlyIfAbsent // check first node without acquiring lock
996	>	&& fh == hash
997	>	&& ((fk = f.key) == key || (fk != null && key.equals(fk)))
998	>	&& (fv = f.val) != null)
999	>	return fv;
1000	>	else {
1001	>	V oldVal = null;
1002	>	synchronized (f) {
1003	>	if (tabAt(tab, i) == f) {
1004	>	if (fh >= 0) {
1005	>	binCount = 1;
1006	>	for (Node<K,V> e = f;; ++binCount) {
1007	>	K ek;
1008	>	if (e.hash == hash &&
1009	>	((ek = e.key) == key ||
1010	>	(ek != null && key.equals(ek)))) {
1011	>	oldVal = e.val;
1012	>	if (!onlyIfAbsent)
1013	>	e.val = value;
1014	>	break;
1015	>	}
1016	>	Node<K,V> pred = e;
1017	>	if ((e = e.next) == null) {
1018	>	pred.next = new Node<K,V>(hash, key, value);
1019	>	break;
1020	>	}
1021	>	}
1022	>	}
1023	>	else if (f instanceof TreeBin) {
1024	>	Node<K,V> p;
1025	>	binCount = 2;
1026	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1027	>	value)) != null) {
1028	>	oldVal = p.val;
1029	>	if (!onlyIfAbsent)
1030	>	p.val = value;
1031	>	}
1032	>	}
1033	>	else if (f instanceof ReservationNode)
1034	>	throw new IllegalStateException("Recursive update");
1035	>	}
1036	>	}
1037	>	if (binCount != 0) {
1038	>	if (binCount >= TREEIFY_THRESHOLD)
1039	>	treeifyBin(tab, i);
1040	>	if (oldVal != null)
1041	>	return oldVal;
1042	>	break;
1043	>	}
1044	>	}
1045	>	}
1046	>	addCount(1L, binCount);
1047	>	return null;
1048	>	}
1049	>
1050	>	/**
1051	>	* Copies all of the mappings from the specified map to this one.
1052	>	* These mappings replace any mappings that this map had for any of the
1053	>	* keys currently in the specified map.
1054	>	*
1055	>	* @param m mappings to be stored in this map
1056	>	*/
1057	>	public void putAll(Map<? extends K, ? extends V> m) {
1058	>	tryPresize(m.size());
1059	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1060	>	putVal(e.getKey(), e.getValue(), false);
1061	>	}
1062	>
1063	>	/**
1064	>	* Removes the key (and its corresponding value) from this map.
1065	>	* This method does nothing if the key is not in the map.
1066	>	*
1067	>	* @param  key the key that needs to be removed
1068	>	* @return the previous value associated with {@code key}, or
1069	>	*         {@code null} if there was no mapping for {@code key}
1070	>	* @throws NullPointerException if the specified key is null
1071	>	*/
1072	>	public V remove(Object key) {
1073	>	return replaceNode(key, null, null);
1074	>	}
1075	>
1076	>	/**
1077	>	* Implementation for the four public remove/replace methods:
1078	>	* Replaces node value with v, conditional upon match of cv if
1079	>	* non-null.  If resulting value is null, delete.
1080	>	*/
1081	>	final V replaceNode(Object key, V value, Object cv) {
1082	>	int hash = spread(key.hashCode());
1083	>	for (Node<K,V>[] tab = table;;) {
1084	>	Node<K,V> f; int n, i, fh;
1085	>	if (tab == null || (n = tab.length) == 0 ||
1086	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1087	>	break;
1088	>	else if ((fh = f.hash) == MOVED)
1089	>	tab = helpTransfer(tab, f);
1090	>	else {
1091	>	V oldVal = null;
1092	>	boolean validated = false;
1093	>	synchronized (f) {
1094	>	if (tabAt(tab, i) == f) {
1095	>	if (fh >= 0) {
1096	>	validated = true;
1097	>	for (Node<K,V> e = f, pred = null;;) {
1098	>	K ek;
1099	>	if (e.hash == hash &&
1100	>	((ek = e.key) == key ||
1101	>	(ek != null && key.equals(ek)))) {
1102	>	V ev = e.val;
1103	>	if (cv == null || cv == ev ||
1104	>	(ev != null && cv.equals(ev))) {
1105	>	oldVal = ev;
1106	>	if (value != null)
1107	>	e.val = value;
1108	>	else if (pred != null)
1109	>	pred.next = e.next;
1110	>	else
1111	>	setTabAt(tab, i, e.next);
1112	>	}
1113	>	break;
1114	>	}
1115	>	pred = e;
1116	>	if ((e = e.next) == null)
1117	>	break;
1118	>	}
1119	>	}
1120	>	else if (f instanceof TreeBin) {
1121	>	validated = true;
1122	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1123	>	TreeNode<K,V> r, p;
1124	>	if ((r = t.root) != null &&
1125	>	(p = r.findTreeNode(hash, key, null)) != null) {
1126	>	V pv = p.val;
1127	>	if (cv == null || cv == pv ||
1128	>	(pv != null && cv.equals(pv))) {
1129	>	oldVal = pv;
1130	>	if (value != null)
1131	>	p.val = value;
1132	>	else if (t.removeTreeNode(p))
1133	>	setTabAt(tab, i, untreeify(t.first));
1134	>	}
1135	>	}
1136	>	}
1137	>	else if (f instanceof ReservationNode)
1138	>	throw new IllegalStateException("Recursive update");
1139	>	}
1140	>	}
1141	>	if (validated) {
1142	>	if (oldVal != null) {
1143	>	if (value == null)
1144	>	addCount(-1L, -1);
1145	>	return oldVal;
1146	>	}
1147	>	break;
1148	>	}
1149	>	}
1150	>	}
1151	>	return null;
1152	>	}
1153
1154		/**
1155	<	* Shift value for indexing within segments.
1156	<	**/
1157	<	private final int segmentShift;
1155	>	* Removes all of the mappings from this map.
1156	>	*/
1157	>	public void clear() {
1158	>	long delta = 0L; // negative number of deletions
1159	>	int i = 0;
1160	>	Node<K,V>[] tab = table;
1161	>	while (tab != null && i < tab.length) {
1162	>	int fh;
1163	>	Node<K,V> f = tabAt(tab, i);
1164	>	if (f == null)
1165	>	++i;
1166	>	else if ((fh = f.hash) == MOVED) {
1167	>	tab = helpTransfer(tab, f);
1168	>	i = 0; // restart
1169	>	}
1170	>	else {
1171	>	synchronized (f) {
1172	>	if (tabAt(tab, i) == f) {
1173	>	Node<K,V> p = (fh >= 0 ? f :
1174	>	(f instanceof TreeBin) ?
1175	>	((TreeBin<K,V>)f).first : null);
1176	>	while (p != null) {
1177	>	--delta;
1178	>	p = p.next;
1179	>	}
1180	>	setTabAt(tab, i++, null);
1181	>	}
1182	>	}
1183	>	}
1184	>	}
1185	>	if (delta != 0L)
1186	>	addCount(delta, -1);
1187	>	}
1188
1189		/**
1190	<	* The segments, each of which is a specialized hash table
1190	>	* Returns a {@link Set} view of the keys contained in this map.
1191	>	* The set is backed by the map, so changes to the map are
1192	>	* reflected in the set, and vice-versa. The set supports element
1193	>	* removal, which removes the corresponding mapping from this map,
1194	>	* via the {@code Iterator.remove}, {@code Set.remove},
1195	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1196	>	* operations.  It does not support the {@code add} or
1197	>	* {@code addAll} operations.
1198	>	*
1199	>	* <p>The view's iterators and spliterators are
1200	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1201	>	*
1202	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1203	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1204	>	*
1205	>	* @return the set view
1206		*/
1207	<	private final Segment[] segments;
1207	>	public KeySetView<K,V> keySet() {
1208	>	KeySetView<K,V> ks;
1209	>	if ((ks = keySet) != null) return ks;
1210	>	return keySet = new KeySetView<K,V>(this, null);
1211	>	}
1212
1213	<	private transient Set<K> keySet;
1214	<	private transient Set<Map.Entry<K,V>> entrySet;
1215	<	private transient Collection<V> values;
1213	>	/**
1214	>	* Returns a {@link Collection} view of the values contained in this map.
1215	>	* The collection is backed by the map, so changes to the map are
1216	>	* reflected in the collection, and vice-versa.  The collection
1217	>	* supports element removal, which removes the corresponding
1218	>	* mapping from this map, via the {@code Iterator.remove},
1219	>	* {@code Collection.remove}, {@code removeAll},
1220	>	* {@code retainAll}, and {@code clear} operations.  It does not
1221	>	* support the {@code add} or {@code addAll} operations.
1222	>	*
1223	>	* <p>The view's iterators and spliterators are
1224	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1225	>	*
1226	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1227	>	* and {@link Spliterator#NONNULL}.
1228	>	*
1229	>	* @return the collection view
1230	>	*/
1231	>	public Collection<V> values() {
1232	>	ValuesView<K,V> vs;
1233	>	if ((vs = values) != null) return vs;
1234	>	return values = new ValuesView<K,V>(this);
1235	>	}
1236
1237	<	/* ---------------- Small Utilities -------------- */
1237	>	/**
1238	>	* Returns a {@link Set} view of the mappings contained in this map.
1239	>	* The set is backed by the map, so changes to the map are
1240	>	* reflected in the set, and vice-versa.  The set supports element
1241	>	* removal, which removes the corresponding mapping from the map,
1242	>	* via the {@code Iterator.remove}, {@code Set.remove},
1243	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1244	>	* operations.
1245	>	*
1246	>	* <p>The view's iterators and spliterators are
1247	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1248	>	*
1249	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1250	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1251	>	*
1252	>	* @return the set view
1253	>	*/
1254	>	public Set<Map.Entry<K,V>> entrySet() {
1255	>	EntrySetView<K,V> es;
1256	>	if ((es = entrySet) != null) return es;
1257	>	return entrySet = new EntrySetView<K,V>(this);
1258	>	}
1259
1260		/**
1261	<	* Return a hash code for non-null Object x.
1262	<	* Uses the same hash code spreader as most other j.u hash tables.
1263	<	* @param x the object serving as a key
1264	<	* @return the hash code
1261	>	* Returns the hash code value for this {@link Map}, i.e.,
1262	>	* the sum of, for each key-value pair in the map,
1263	>	* {@code key.hashCode() ^ value.hashCode()}.
1264	>	*
1265	>	* @return the hash code value for this map
1266		*/
1267	<	private static int hash(Object x) {
1268	<	int h = x.hashCode();
1269	<	h += ~(h << 9);
1270	<	h ^=  (h >>> 14);
1271	<	h +=  (h << 4);
1272	<	h ^=  (h >>> 10);
1267	>	public int hashCode() {
1268	>	int h = 0;
1269	>	Node<K,V>[] t;
1270	>	if ((t = table) != null) {
1271	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1272	>	for (Node<K,V> p; (p = it.advance()) != null; )
1273	>	h += p.key.hashCode() ^ p.val.hashCode();
1274	>	}
1275		return h;
1276		}
1277
1278		/**
1279	<	* Return the segment that should be used for key with given hash
1279	>	* Returns a string representation of this map.  The string
1280	>	* representation consists of a list of key-value mappings (in no
1281	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1282	>	* mappings are separated by the characters {@code ", "} (comma
1283	>	* and space).  Each key-value mapping is rendered as the key
1284	>	* followed by an equals sign ("{@code =}") followed by the
1285	>	* associated value.
1286	>	*
1287	>	* @return a string representation of this map
1288	>	*/
1289	>	public String toString() {
1290	>	Node<K,V>[] t;
1291	>	int f = (t = table) == null ? 0 : t.length;
1292	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1293	>	StringBuilder sb = new StringBuilder();
1294	>	sb.append('{');
1295	>	Node<K,V> p;
1296	>	if ((p = it.advance()) != null) {
1297	>	for (;;) {
1298	>	K k = p.key;
1299	>	V v = p.val;
1300	>	sb.append(k == this ? "(this Map)" : k);
1301	>	sb.append('=');
1302	>	sb.append(v == this ? "(this Map)" : v);
1303	>	if ((p = it.advance()) == null)
1304	>	break;
1305	>	sb.append(',').append(' ');
1306	>	}
1307	>	}
1308	>	return sb.append('}').toString();
1309	>	}
1310	>
1311	>	/**
1312	>	* Compares the specified object with this map for equality.
1313	>	* Returns {@code true} if the given object is a map with the same
1314	>	* mappings as this map.  This operation may return misleading
1315	>	* results if either map is concurrently modified during execution
1316	>	* of this method.
1317	>	*
1318	>	* @param o object to be compared for equality with this map
1319	>	* @return {@code true} if the specified object is equal to this map
1320	>	*/
1321	>	public boolean equals(Object o) {
1322	>	if (o != this) {
1323	>	if (!(o instanceof Map))
1324	>	return false;
1325	>	Map<?,?> m = (Map<?,?>) o;
1326	>	Node<K,V>[] t;
1327	>	int f = (t = table) == null ? 0 : t.length;
1328	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1329	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1330	>	V val = p.val;
1331	>	Object v = m.get(p.key);
1332	>	if (v == null || (v != val && !v.equals(val)))
1333	>	return false;
1334	>	}
1335	>	for (Map.Entry<?,?> e : m.entrySet()) {
1336	>	Object mk, mv, v;
1337	>	if ((mk = e.getKey()) == null ||
1338	>	(mv = e.getValue()) == null ||
1339	>	(v = get(mk)) == null ||
1340	>	(mv != v && !mv.equals(v)))
1341	>	return false;
1342	>	}
1343	>	}
1344	>	return true;
1345	>	}
1346	>
1347	>	/**
1348	>	* Stripped-down version of helper class used in previous version,
1349	>	* declared for the sake of serialization compatibility.
1350		*/
1351	<	private Segment<K,V> segmentFor(int hash) {
1352	<	return (Segment<K,V>) segments[(hash >>> segmentShift) & segmentMask];
1351	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1352	>	private static final long serialVersionUID = 2249069246763182397L;
1353	>	final float loadFactor;
1354	>	Segment(float lf) { this.loadFactor = lf; }
1355		}
1356
1357	<	/* ---------------- Inner Classes -------------- */
1357	>	/**
1358	>	* Saves this map to a stream (that is, serializes it).
1359	>	*
1360	>	* @param s the stream
1361	>	* @throws java.io.IOException if an I/O error occurs
1362	>	* @serialData
1363	>	* the serialized fields, followed by the key (Object) and value
1364	>	* (Object) for each key-value mapping, followed by a null pair.
1365	>	* The key-value mappings are emitted in no particular order.
1366	>	*/
1367	>	private void writeObject(java.io.ObjectOutputStream s)
1368	>	throws java.io.IOException {
1369	>	// For serialization compatibility
1370	>	// Emulate segment calculation from previous version of this class
1371	>	int sshift = 0;
1372	>	int ssize = 1;
1373	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1374	>	++sshift;
1375	>	ssize <<= 1;
1376	>	}
1377	>	int segmentShift = 32 - sshift;
1378	>	int segmentMask = ssize - 1;
1379	>	@SuppressWarnings("unchecked")
1380	>	Segment<K,V>[] segments = (Segment<K,V>[])
1381	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1382	>	for (int i = 0; i < segments.length; ++i)
1383	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1384	>	java.io.ObjectOutputStream.PutField streamFields = s.putFields();
1385	>	streamFields.put("segments", segments);
1386	>	streamFields.put("segmentShift", segmentShift);
1387	>	streamFields.put("segmentMask", segmentMask);
1388	>	s.writeFields();
1389	>
1390	>	Node<K,V>[] t;
1391	>	if ((t = table) != null) {
1392	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1393	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1394	>	s.writeObject(p.key);
1395	>	s.writeObject(p.val);
1396	>	}
1397	>	}
1398	>	s.writeObject(null);
1399	>	s.writeObject(null);
1400	>	}
1401
1402		/**
1403	<	* Segments are specialized versions of hash tables.  This
1404	<	* subclasses from ReentrantLock opportunistically, just to
1405	<	* simplify some locking and avoid separate construction.
1406	<	**/
1407	<	private static final class Segment<K,V> extends ReentrantLock implements Serializable {
1403	>	* Reconstitutes this map from a stream (that is, deserializes it).
1404	>	* @param s the stream
1405	>	* @throws ClassNotFoundException if the class of a serialized object
1406	>	*         could not be found
1407	>	* @throws java.io.IOException if an I/O error occurs
1408	>	*/
1409	>	private void readObject(java.io.ObjectInputStream s)
1410	>	throws java.io.IOException, ClassNotFoundException {
1411		/*
1412	<	* Segments maintain a table of entry lists that are ALWAYS
1413	<	* kept in a consistent state, so can be read without locking.
1414	<	* Next fields of nodes are immutable (final).  All list
1415	<	* additions are performed at the front of each bin. This
1416	<	* makes it easy to check changes, and also fast to traverse.
150	<	* When nodes would otherwise be changed, new nodes are
151	<	* created to replace them. This works well for hash tables
152	<	* since the bin lists tend to be short. (The average length
153	<	* is less than two for the default load factor threshold.)
154	<	*
155	<	* Read operations can thus proceed without locking, but rely
156	<	* on a memory barrier to ensure that completed write
157	<	* operations performed by other threads are
158	<	* noticed. Conveniently, the "count" field, tracking the
159	<	* number of elements, can also serve as the volatile variable
160	<	* providing proper read/write barriers. This is convenient
161	<	* because this field needs to be read in many read operations
162	<	* anyway. The use of volatiles for this purpose is only
163	<	* guaranteed to work in accord with reuirements in
164	<	* multithreaded environments when run on JVMs conforming to
165	<	* the clarified JSR133 memory model specification.  This true
166	<	* for hotspot as of release 1.4.
167	<	*
168	<	* Implementors note. The basic rules for all this are:
169	<	*
170	<	*   - All unsynchronized read operations must first read the
171	<	*     "count" field, and should not look at table entries if
172	<	*     it is 0.
173	<	*
174	<	*   - All synchronized write operations should write to
175	<	*     the "count" field after updating. The operations must not
176	<	*     take any action that could even momentarily cause
177	<	*     a concurrent read operation to see inconsistent
178	<	*     data. This is made easier by the nature of the read
179	<	*     operations in Map. For example, no operation
180	<	*     can reveal that the table has grown but the threshold
181	<	*     has not yet been updated, so there are no atomicity
182	<	*     requirements for this with respect to reads.
183	<	*
184	<	* As a guide, all critical volatile reads and writes are marked
185	<	* in code comments.
1412	>	* To improve performance in typical cases, we create nodes
1413	>	* while reading, then place in table once size is known.
1414	>	* However, we must also validate uniqueness and deal with
1415	>	* overpopulated bins while doing so, which requires
1416	>	* specialized versions of putVal mechanics.
1417		*/
1418	+	sizeCtl = -1; // force exclusion for table construction
1419	+	s.defaultReadObject();
1420	+	long size = 0L;
1421	+	Node<K,V> p = null;
1422	+	for (;;) {
1423	+	@SuppressWarnings("unchecked")
1424	+	K k = (K) s.readObject();
1425	+	@SuppressWarnings("unchecked")
1426	+	V v = (V) s.readObject();
1427	+	if (k != null && v != null) {
1428	+	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1429	+	++size;
1430	+	}
1431	+	else
1432	+	break;
1433	+	}
1434	+	if (size == 0L)
1435	+	sizeCtl = 0;
1436	+	else {
1437	+	long ts = (long)(1.0 + size / LOAD_FACTOR);
1438	+	int n = (ts >= (long)MAXIMUM_CAPACITY) ?
1439	+	MAXIMUM_CAPACITY : tableSizeFor((int)ts);
1440	+	@SuppressWarnings("unchecked")
1441	+	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1442	+	int mask = n - 1;
1443	+	long added = 0L;
1444	+	while (p != null) {
1445	+	boolean insertAtFront;
1446	+	Node<K,V> next = p.next, first;
1447	+	int h = p.hash, j = h & mask;
1448	+	if ((first = tabAt(tab, j)) == null)
1449	+	insertAtFront = true;
1450	+	else {
1451	+	K k = p.key;
1452	+	if (first.hash < 0) {
1453	+	TreeBin<K,V> t = (TreeBin<K,V>)first;
1454	+	if (t.putTreeVal(h, k, p.val) == null)
1455	+	++added;
1456	+	insertAtFront = false;
1457	+	}
1458	+	else {
1459	+	int binCount = 0;
1460	+	insertAtFront = true;
1461	+	Node<K,V> q; K qk;
1462	+	for (q = first; q != null; q = q.next) {
1463	+	if (q.hash == h &&
1464	+	((qk = q.key) == k ||
1465	+	(qk != null && k.equals(qk)))) {
1466	+	insertAtFront = false;
1467	+	break;
1468	+	}
1469	+	++binCount;
1470	+	}
1471	+	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1472	+	insertAtFront = false;
1473	+	++added;
1474	+	p.next = first;
1475	+	TreeNode<K,V> hd = null, tl = null;
1476	+	for (q = p; q != null; q = q.next) {
1477	+	TreeNode<K,V> t = new TreeNode<K,V>
1478	+	(q.hash, q.key, q.val, null, null);
1479	+	if ((t.prev = tl) == null)
1480	+	hd = t;
1481	+	else
1482	+	tl.next = t;
1483	+	tl = t;
1484	+	}
1485	+	setTabAt(tab, j, new TreeBin<K,V>(hd));
1486	+	}
1487	+	}
1488	+	}
1489	+	if (insertAtFront) {
1490	+	++added;
1491	+	p.next = first;
1492	+	setTabAt(tab, j, p);
1493	+	}
1494	+	p = next;
1495	+	}
1496	+	table = tab;
1497	+	sizeCtl = n - (n >>> 2);
1498	+	baseCount = added;
1499	+	}
1500	+	}
1501
1502	<	/**
1503	<	* The number of elements in this segment's region.
1504	<	**/
1505	<	transient volatile int count;
1502	>	// ConcurrentMap methods
1503	>
1504	>	/**
1505	>	* {@inheritDoc}
1506	>	*
1507	>	* @return the previous value associated with the specified key,
1508	>	*         or {@code null} if there was no mapping for the key
1509	>	* @throws NullPointerException if the specified key or value is null
1510	>	*/
1511	>	public V putIfAbsent(K key, V value) {
1512	>	return putVal(key, value, true);
1513	>	}
1514	>
1515	>	/**
1516	>	* {@inheritDoc}
1517	>	*
1518	>	* @throws NullPointerException if the specified key is null
1519	>	*/
1520	>	public boolean remove(Object key, Object value) {
1521	>	if (key == null)
1522	>	throw new NullPointerException();
1523	>	return value != null && replaceNode(key, null, value) != null;
1524	>	}
1525	>
1526	>	/**
1527	>	* {@inheritDoc}
1528	>	*
1529	>	* @throws NullPointerException if any of the arguments are null
1530	>	*/
1531	>	public boolean replace(K key, V oldValue, V newValue) {
1532	>	if (key == null || oldValue == null || newValue == null)
1533	>	throw new NullPointerException();
1534	>	return replaceNode(key, newValue, oldValue) != null;
1535	>	}
1536	>
1537	>	/**
1538	>	* {@inheritDoc}
1539	>	*
1540	>	* @return the previous value associated with the specified key,
1541	>	*         or {@code null} if there was no mapping for the key
1542	>	* @throws NullPointerException if the specified key or value is null
1543	>	*/
1544	>	public V replace(K key, V value) {
1545	>	if (key == null || value == null)
1546	>	throw new NullPointerException();
1547	>	return replaceNode(key, value, null);
1548	>	}
1549	>
1550	>	// Overrides of JDK8+ Map extension method defaults
1551	>
1552	>	/**
1553	>	* Returns the value to which the specified key is mapped, or the
1554	>	* given default value if this map contains no mapping for the
1555	>	* key.
1556	>	*
1557	>	* @param key the key whose associated value is to be returned
1558	>	* @param defaultValue the value to return if this map contains
1559	>	* no mapping for the given key
1560	>	* @return the mapping for the key, if present; else the default value
1561	>	* @throws NullPointerException if the specified key is null
1562	>	*/
1563	>	public V getOrDefault(Object key, V defaultValue) {
1564	>	V v;
1565	>	return (v = get(key)) == null ? defaultValue : v;
1566	>	}
1567	>
1568	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1569	>	if (action == null) throw new NullPointerException();
1570	>	Node<K,V>[] t;
1571	>	if ((t = table) != null) {
1572	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1573	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1574	>	action.accept(p.key, p.val);
1575	>	}
1576	>	}
1577	>	}
1578	>
1579	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1580	>	if (function == null) throw new NullPointerException();
1581	>	Node<K,V>[] t;
1582	>	if ((t = table) != null) {
1583	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1584	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1585	>	V oldValue = p.val;
1586	>	for (K key = p.key;;) {
1587	>	V newValue = function.apply(key, oldValue);
1588	>	if (newValue == null)
1589	>	throw new NullPointerException();
1590	>	if (replaceNode(key, newValue, oldValue) != null ||
1591	>	(oldValue = get(key)) == null)
1592	>	break;
1593	>	}
1594	>	}
1595	>	}
1596	>	}
1597	>
1598	>	/**
1599	>	* Helper method for EntrySetView.removeIf.
1600	>	*/
1601	>	boolean removeEntryIf(Predicate<? super Entry<K,V>> function) {
1602	>	if (function == null) throw new NullPointerException();
1603	>	Node<K,V>[] t;
1604	>	boolean removed = false;
1605	>	if ((t = table) != null) {
1606	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1607	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1608	>	K k = p.key;
1609	>	V v = p.val;
1610	>	Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v);
1611	>	if (function.test(e) && replaceNode(k, null, v) != null)
1612	>	removed = true;
1613	>	}
1614	>	}
1615	>	return removed;
1616	>	}
1617	>
1618	>	/**
1619	>	* Helper method for ValuesView.removeIf.
1620	>	*/
1621	>	boolean removeValueIf(Predicate<? super V> function) {
1622	>	if (function == null) throw new NullPointerException();
1623	>	Node<K,V>[] t;
1624	>	boolean removed = false;
1625	>	if ((t = table) != null) {
1626	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1627	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1628	>	K k = p.key;
1629	>	V v = p.val;
1630	>	if (function.test(v) && replaceNode(k, null, v) != null)
1631	>	removed = true;
1632	>	}
1633	>	}
1634	>	return removed;
1635	>	}
1636	>
1637	>	/**
1638	>	* If the specified key is not already associated with a value,
1639	>	* attempts to compute its value using the given mapping function
1640	>	* and enters it into this map unless {@code null}.  The entire
1641	>	* method invocation is performed atomically, so the function is
1642	>	* applied at most once per key.  Some attempted update operations
1643	>	* on this map by other threads may be blocked while computation
1644	>	* is in progress, so the computation should be short and simple,
1645	>	* and must not attempt to update any other mappings of this map.
1646	>	*
1647	>	* @param key key with which the specified value is to be associated
1648	>	* @param mappingFunction the function to compute a value
1649	>	* @return the current (existing or computed) value associated with
1650	>	*         the specified key, or null if the computed value is null
1651	>	* @throws NullPointerException if the specified key or mappingFunction
1652	>	*         is null
1653	>	* @throws IllegalStateException if the computation detectably
1654	>	*         attempts a recursive update to this map that would
1655	>	*         otherwise never complete
1656	>	* @throws RuntimeException or Error if the mappingFunction does so,
1657	>	*         in which case the mapping is left unestablished
1658	>	*/
1659	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1660	>	if (key == null || mappingFunction == null)
1661	>	throw new NullPointerException();
1662	>	int h = spread(key.hashCode());
1663	>	V val = null;
1664	>	int binCount = 0;
1665	>	for (Node<K,V>[] tab = table;;) {
1666	>	Node<K,V> f; int n, i, fh; K fk; V fv;
1667	>	if (tab == null || (n = tab.length) == 0)
1668	>	tab = initTable();
1669	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1670	>	Node<K,V> r = new ReservationNode<K,V>();
1671	>	synchronized (r) {
1672	>	if (casTabAt(tab, i, null, r)) {
1673	>	binCount = 1;
1674	>	Node<K,V> node = null;
1675	>	try {
1676	>	if ((val = mappingFunction.apply(key)) != null)
1677	>	node = new Node<K,V>(h, key, val);
1678	>	} finally {
1679	>	setTabAt(tab, i, node);
1680	>	}
1681	>	}
1682	>	}
1683	>	if (binCount != 0)
1684	>	break;
1685	>	}
1686	>	else if ((fh = f.hash) == MOVED)
1687	>	tab = helpTransfer(tab, f);
1688	>	else if (fh == h    // check first node without acquiring lock
1689	>	&& ((fk = f.key) == key || (fk != null && key.equals(fk)))
1690	>	&& (fv = f.val) != null)
1691	>	return fv;
1692	>	else {
1693	>	boolean added = false;
1694	>	synchronized (f) {
1695	>	if (tabAt(tab, i) == f) {
1696	>	if (fh >= 0) {
1697	>	binCount = 1;
1698	>	for (Node<K,V> e = f;; ++binCount) {
1699	>	K ek;
1700	>	if (e.hash == h &&
1701	>	((ek = e.key) == key ||
1702	>	(ek != null && key.equals(ek)))) {
1703	>	val = e.val;
1704	>	break;
1705	>	}
1706	>	Node<K,V> pred = e;
1707	>	if ((e = e.next) == null) {
1708	>	if ((val = mappingFunction.apply(key)) != null) {
1709	>	if (pred.next != null)
1710	>	throw new IllegalStateException("Recursive update");
1711	>	added = true;
1712	>	pred.next = new Node<K,V>(h, key, val);
1713	>	}
1714	>	break;
1715	>	}
1716	>	}
1717	>	}
1718	>	else if (f instanceof TreeBin) {
1719	>	binCount = 2;
1720	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1721	>	TreeNode<K,V> r, p;
1722	>	if ((r = t.root) != null &&
1723	>	(p = r.findTreeNode(h, key, null)) != null)
1724	>	val = p.val;
1725	>	else if ((val = mappingFunction.apply(key)) != null) {
1726	>	added = true;
1727	>	t.putTreeVal(h, key, val);
1728	>	}
1729	>	}
1730	>	else if (f instanceof ReservationNode)
1731	>	throw new IllegalStateException("Recursive update");
1732	>	}
1733	>	}
1734	>	if (binCount != 0) {
1735	>	if (binCount >= TREEIFY_THRESHOLD)
1736	>	treeifyBin(tab, i);
1737	>	if (!added)
1738	>	return val;
1739	>	break;
1740	>	}
1741	>	}
1742	>	}
1743	>	if (val != null)
1744	>	addCount(1L, binCount);
1745	>	return val;
1746	>	}
1747	>
1748	>	/**
1749	>	* If the value for the specified key is present, attempts to
1750	>	* compute a new mapping given the key and its current mapped
1751	>	* value.  The entire method invocation is performed atomically.
1752	>	* Some attempted update operations on this map by other threads
1753	>	* may be blocked while computation is in progress, so the
1754	>	* computation should be short and simple, and must not attempt to
1755	>	* update any other mappings of this map.
1756	>	*
1757	>	* @param key key with which a value may be associated
1758	>	* @param remappingFunction the function to compute a value
1759	>	* @return the new value associated with the specified key, or null if none
1760	>	* @throws NullPointerException if the specified key or remappingFunction
1761	>	*         is null
1762	>	* @throws IllegalStateException if the computation detectably
1763	>	*         attempts a recursive update to this map that would
1764	>	*         otherwise never complete
1765	>	* @throws RuntimeException or Error if the remappingFunction does so,
1766	>	*         in which case the mapping is unchanged
1767	>	*/
1768	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1769	>	if (key == null || remappingFunction == null)
1770	>	throw new NullPointerException();
1771	>	int h = spread(key.hashCode());
1772	>	V val = null;
1773	>	int delta = 0;
1774	>	int binCount = 0;
1775	>	for (Node<K,V>[] tab = table;;) {
1776	>	Node<K,V> f; int n, i, fh;
1777	>	if (tab == null || (n = tab.length) == 0)
1778	>	tab = initTable();
1779	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1780	>	break;
1781	>	else if ((fh = f.hash) == MOVED)
1782	>	tab = helpTransfer(tab, f);
1783	>	else {
1784	>	synchronized (f) {
1785	>	if (tabAt(tab, i) == f) {
1786	>	if (fh >= 0) {
1787	>	binCount = 1;
1788	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1789	>	K ek;
1790	>	if (e.hash == h &&
1791	>	((ek = e.key) == key ||
1792	>	(ek != null && key.equals(ek)))) {
1793	>	val = remappingFunction.apply(key, e.val);
1794	>	if (val != null)
1795	>	e.val = val;
1796	>	else {
1797	>	delta = -1;
1798	>	Node<K,V> en = e.next;
1799	>	if (pred != null)
1800	>	pred.next = en;
1801	>	else
1802	>	setTabAt(tab, i, en);
1803	>	}
1804	>	break;
1805	>	}
1806	>	pred = e;
1807	>	if ((e = e.next) == null)
1808	>	break;
1809	>	}
1810	>	}
1811	>	else if (f instanceof TreeBin) {
1812	>	binCount = 2;
1813	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1814	>	TreeNode<K,V> r, p;
1815	>	if ((r = t.root) != null &&
1816	>	(p = r.findTreeNode(h, key, null)) != null) {
1817	>	val = remappingFunction.apply(key, p.val);
1818	>	if (val != null)
1819	>	p.val = val;
1820	>	else {
1821	>	delta = -1;
1822	>	if (t.removeTreeNode(p))
1823	>	setTabAt(tab, i, untreeify(t.first));
1824	>	}
1825	>	}
1826	>	}
1827	>	else if (f instanceof ReservationNode)
1828	>	throw new IllegalStateException("Recursive update");
1829	>	}
1830	>	}
1831	>	if (binCount != 0)
1832	>	break;
1833	>	}
1834	>	}
1835	>	if (delta != 0)
1836	>	addCount((long)delta, binCount);
1837	>	return val;
1838	>	}
1839	>
1840	>	/**
1841	>	* Attempts to compute a mapping for the specified key and its
1842	>	* current mapped value (or {@code null} if there is no current
1843	>	* mapping). The entire method invocation is performed atomically.
1844	>	* Some attempted update operations on this map by other threads
1845	>	* may be blocked while computation is in progress, so the
1846	>	* computation should be short and simple, and must not attempt to
1847	>	* update any other mappings of this Map.
1848	>	*
1849	>	* @param key key with which the specified value is to be associated
1850	>	* @param remappingFunction the function to compute a value
1851	>	* @return the new value associated with the specified key, or null if none
1852	>	* @throws NullPointerException if the specified key or remappingFunction
1853	>	*         is null
1854	>	* @throws IllegalStateException if the computation detectably
1855	>	*         attempts a recursive update to this map that would
1856	>	*         otherwise never complete
1857	>	* @throws RuntimeException or Error if the remappingFunction does so,
1858	>	*         in which case the mapping is unchanged
1859	>	*/
1860	>	public V compute(K key,
1861	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1862	>	if (key == null || remappingFunction == null)
1863	>	throw new NullPointerException();
1864	>	int h = spread(key.hashCode());
1865	>	V val = null;
1866	>	int delta = 0;
1867	>	int binCount = 0;
1868	>	for (Node<K,V>[] tab = table;;) {
1869	>	Node<K,V> f; int n, i, fh;
1870	>	if (tab == null || (n = tab.length) == 0)
1871	>	tab = initTable();
1872	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1873	>	Node<K,V> r = new ReservationNode<K,V>();
1874	>	synchronized (r) {
1875	>	if (casTabAt(tab, i, null, r)) {
1876	>	binCount = 1;
1877	>	Node<K,V> node = null;
1878	>	try {
1879	>	if ((val = remappingFunction.apply(key, null)) != null) {
1880	>	delta = 1;
1881	>	node = new Node<K,V>(h, key, val);
1882	>	}
1883	>	} finally {
1884	>	setTabAt(tab, i, node);
1885	>	}
1886	>	}
1887	>	}
1888	>	if (binCount != 0)
1889	>	break;
1890	>	}
1891	>	else if ((fh = f.hash) == MOVED)
1892	>	tab = helpTransfer(tab, f);
1893	>	else {
1894	>	synchronized (f) {
1895	>	if (tabAt(tab, i) == f) {
1896	>	if (fh >= 0) {
1897	>	binCount = 1;
1898	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1899	>	K ek;
1900	>	if (e.hash == h &&
1901	>	((ek = e.key) == key ||
1902	>	(ek != null && key.equals(ek)))) {
1903	>	val = remappingFunction.apply(key, e.val);
1904	>	if (val != null)
1905	>	e.val = val;
1906	>	else {
1907	>	delta = -1;
1908	>	Node<K,V> en = e.next;
1909	>	if (pred != null)
1910	>	pred.next = en;
1911	>	else
1912	>	setTabAt(tab, i, en);
1913	>	}
1914	>	break;
1915	>	}
1916	>	pred = e;
1917	>	if ((e = e.next) == null) {
1918	>	val = remappingFunction.apply(key, null);
1919	>	if (val != null) {
1920	>	if (pred.next != null)
1921	>	throw new IllegalStateException("Recursive update");
1922	>	delta = 1;
1923	>	pred.next = new Node<K,V>(h, key, val);
1924	>	}
1925	>	break;
1926	>	}
1927	>	}
1928	>	}
1929	>	else if (f instanceof TreeBin) {
1930	>	binCount = 1;
1931	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1932	>	TreeNode<K,V> r, p;
1933	>	if ((r = t.root) != null)
1934	>	p = r.findTreeNode(h, key, null);
1935	>	else
1936	>	p = null;
1937	>	V pv = (p == null) ? null : p.val;
1938	>	val = remappingFunction.apply(key, pv);
1939	>	if (val != null) {
1940	>	if (p != null)
1941	>	p.val = val;
1942	>	else {
1943	>	delta = 1;
1944	>	t.putTreeVal(h, key, val);
1945	>	}
1946	>	}
1947	>	else if (p != null) {
1948	>	delta = -1;
1949	>	if (t.removeTreeNode(p))
1950	>	setTabAt(tab, i, untreeify(t.first));
1951	>	}
1952	>	}
1953	>	else if (f instanceof ReservationNode)
1954	>	throw new IllegalStateException("Recursive update");
1955	>	}
1956	>	}
1957	>	if (binCount != 0) {
1958	>	if (binCount >= TREEIFY_THRESHOLD)
1959	>	treeifyBin(tab, i);
1960	>	break;
1961	>	}
1962	>	}
1963	>	}
1964	>	if (delta != 0)
1965	>	addCount((long)delta, binCount);
1966	>	return val;
1967	>	}
1968	>
1969	>	/**
1970	>	* If the specified key is not already associated with a
1971	>	* (non-null) value, associates it with the given value.
1972	>	* Otherwise, replaces the value with the results of the given
1973	>	* remapping function, or removes if {@code null}. The entire
1974	>	* method invocation is performed atomically.  Some attempted
1975	>	* update operations on this map by other threads may be blocked
1976	>	* while computation is in progress, so the computation should be
1977	>	* short and simple, and must not attempt to update any other
1978	>	* mappings of this Map.
1979	>	*
1980	>	* @param key key with which the specified value is to be associated
1981	>	* @param value the value to use if absent
1982	>	* @param remappingFunction the function to recompute a value if present
1983	>	* @return the new value associated with the specified key, or null if none
1984	>	* @throws NullPointerException if the specified key or the
1985	>	*         remappingFunction is null
1986	>	* @throws RuntimeException or Error if the remappingFunction does so,
1987	>	*         in which case the mapping is unchanged
1988	>	*/
1989	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1990	>	if (key == null || value == null || remappingFunction == null)
1991	>	throw new NullPointerException();
1992	>	int h = spread(key.hashCode());
1993	>	V val = null;
1994	>	int delta = 0;
1995	>	int binCount = 0;
1996	>	for (Node<K,V>[] tab = table;;) {
1997	>	Node<K,V> f; int n, i, fh;
1998	>	if (tab == null || (n = tab.length) == 0)
1999	>	tab = initTable();
2000	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
2001	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value))) {
2002	>	delta = 1;
2003	>	val = value;
2004	>	break;
2005	>	}
2006	>	}
2007	>	else if ((fh = f.hash) == MOVED)
2008	>	tab = helpTransfer(tab, f);
2009	>	else {
2010	>	synchronized (f) {
2011	>	if (tabAt(tab, i) == f) {
2012	>	if (fh >= 0) {
2013	>	binCount = 1;
2014	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
2015	>	K ek;
2016	>	if (e.hash == h &&
2017	>	((ek = e.key) == key ||
2018	>	(ek != null && key.equals(ek)))) {
2019	>	val = remappingFunction.apply(e.val, value);
2020	>	if (val != null)
2021	>	e.val = val;
2022	>	else {
2023	>	delta = -1;
2024	>	Node<K,V> en = e.next;
2025	>	if (pred != null)
2026	>	pred.next = en;
2027	>	else
2028	>	setTabAt(tab, i, en);
2029	>	}
2030	>	break;
2031	>	}
2032	>	pred = e;
2033	>	if ((e = e.next) == null) {
2034	>	delta = 1;
2035	>	val = value;
2036	>	pred.next = new Node<K,V>(h, key, val);
2037	>	break;
2038	>	}
2039	>	}
2040	>	}
2041	>	else if (f instanceof TreeBin) {
2042	>	binCount = 2;
2043	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2044	>	TreeNode<K,V> r = t.root;
2045	>	TreeNode<K,V> p = (r == null) ? null :
2046	>	r.findTreeNode(h, key, null);
2047	>	val = (p == null) ? value :
2048	>	remappingFunction.apply(p.val, value);
2049	>	if (val != null) {
2050	>	if (p != null)
2051	>	p.val = val;
2052	>	else {
2053	>	delta = 1;
2054	>	t.putTreeVal(h, key, val);
2055	>	}
2056	>	}
2057	>	else if (p != null) {
2058	>	delta = -1;
2059	>	if (t.removeTreeNode(p))
2060	>	setTabAt(tab, i, untreeify(t.first));
2061	>	}
2062	>	}
2063	>	else if (f instanceof ReservationNode)
2064	>	throw new IllegalStateException("Recursive update");
2065	>	}
2066	>	}
2067	>	if (binCount != 0) {
2068	>	if (binCount >= TREEIFY_THRESHOLD)
2069	>	treeifyBin(tab, i);
2070	>	break;
2071	>	}
2072	>	}
2073	>	}
2074	>	if (delta != 0)
2075	>	addCount((long)delta, binCount);
2076	>	return val;
2077	>	}
2078	>
2079	>	// Hashtable legacy methods
2080	>
2081	>	/**
2082	>	* Tests if some key maps into the specified value in this table.
2083	>	*
2084	>	* <p>Note that this method is identical in functionality to
2085	>	* {@link #containsValue(Object)}, and exists solely to ensure
2086	>	* full compatibility with class {@link java.util.Hashtable},
2087	>	* which supported this method prior to introduction of the
2088	>	* Java Collections Framework.
2089	>	*
2090	>	* @param  value a value to search for
2091	>	* @return {@code true} if and only if some key maps to the
2092	>	*         {@code value} argument in this table as
2093	>	*         determined by the {@code equals} method;
2094	>	*         {@code false} otherwise
2095	>	* @throws NullPointerException if the specified value is null
2096	>	*/
2097	>	public boolean contains(Object value) {
2098	>	return containsValue(value);
2099	>	}
2100	>
2101	>	/**
2102	>	* Returns an enumeration of the keys in this table.
2103	>	*
2104	>	* @return an enumeration of the keys in this table
2105	>	* @see #keySet()
2106	>	*/
2107	>	public Enumeration<K> keys() {
2108	>	Node<K,V>[] t;
2109	>	int f = (t = table) == null ? 0 : t.length;
2110	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2111	>	}
2112	>
2113	>	/**
2114	>	* Returns an enumeration of the values in this table.
2115	>	*
2116	>	* @return an enumeration of the values in this table
2117	>	* @see #values()
2118	>	*/
2119	>	public Enumeration<V> elements() {
2120	>	Node<K,V>[] t;
2121	>	int f = (t = table) == null ? 0 : t.length;
2122	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2123	>	}
2124	>
2125	>	// ConcurrentHashMap-only methods
2126	>
2127	>	/**
2128	>	* Returns the number of mappings. This method should be used
2129	>	* instead of {@link #size} because a ConcurrentHashMap may
2130	>	* contain more mappings than can be represented as an int. The
2131	>	* value returned is an estimate; the actual count may differ if
2132	>	* there are concurrent insertions or removals.
2133	>	*
2134	>	* @return the number of mappings
2135	>	* @since 1.8
2136	>	*/
2137	>	public long mappingCount() {
2138	>	long n = sumCount();
2139	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2140	>	}
2141	>
2142	>	/**
2143	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2144	>	* from the given type to {@code Boolean.TRUE}.
2145	>	*
2146	>	* @param <K> the element type of the returned set
2147	>	* @return the new set
2148	>	* @since 1.8
2149	>	*/
2150	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2151	>	return new KeySetView<K,Boolean>
2152	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2153	>	}
2154	>
2155	>	/**
2156	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2157	>	* from the given type to {@code Boolean.TRUE}.
2158	>	*
2159	>	* @param initialCapacity The implementation performs internal
2160	>	* sizing to accommodate this many elements.
2161	>	* @param <K> the element type of the returned set
2162	>	* @return the new set
2163	>	* @throws IllegalArgumentException if the initial capacity of
2164	>	* elements is negative
2165	>	* @since 1.8
2166	>	*/
2167	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2168	>	return new KeySetView<K,Boolean>
2169	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2170	>	}
2171	>
2172	>	/**
2173	>	* Returns a {@link Set} view of the keys in this map, using the
2174	>	* given common mapped value for any additions (i.e., {@link
2175	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2176	>	* This is of course only appropriate if it is acceptable to use
2177	>	* the same value for all additions from this view.
2178	>	*
2179	>	* @param mappedValue the mapped value to use for any additions
2180	>	* @return the set view
2181	>	* @throws NullPointerException if the mappedValue is null
2182	>	*/
2183	>	public KeySetView<K,V> keySet(V mappedValue) {
2184	>	if (mappedValue == null)
2185	>	throw new NullPointerException();
2186	>	return new KeySetView<K,V>(this, mappedValue);
2187	>	}
2188	>
2189	>	/* ---------------- Special Nodes -------------- */
2190	>
2191	>	/**
2192	>	* A node inserted at head of bins during transfer operations.
2193	>	*/
2194	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2195	>	final Node<K,V>[] nextTable;
2196	>	ForwardingNode(Node<K,V>[] tab) {
2197	>	super(MOVED, null, null);
2198	>	this.nextTable = tab;
2199	>	}
2200	>
2201	>	Node<K,V> find(int h, Object k) {
2202	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2203	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2204	>	Node<K,V> e; int n;
2205	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2206	>	(e = tabAt(tab, (n - 1) & h)) == null)
2207	>	return null;
2208	>	for (;;) {
2209	>	int eh; K ek;
2210	>	if ((eh = e.hash) == h &&
2211	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2212	>	return e;
2213	>	if (eh < 0) {
2214	>	if (e instanceof ForwardingNode) {
2215	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2216	>	continue outer;
2217	>	}
2218	>	else
2219	>	return e.find(h, k);
2220	>	}
2221	>	if ((e = e.next) == null)
2222	>	return null;
2223	>	}
2224	>	}
2225	>	}
2226	>	}
2227	>
2228	>	/**
2229	>	* A place-holder node used in computeIfAbsent and compute.
2230	>	*/
2231	>	static final class ReservationNode<K,V> extends Node<K,V> {
2232	>	ReservationNode() {
2233	>	super(RESERVED, null, null);
2234	>	}
2235	>
2236	>	Node<K,V> find(int h, Object k) {
2237	>	return null;
2238	>	}
2239	>	}
2240	>
2241	>	/* ---------------- Table Initialization and Resizing -------------- */
2242	>
2243	>	/**
2244	>	* Returns the stamp bits for resizing a table of size n.
2245	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2246	>	*/
2247	>	static final int resizeStamp(int n) {
2248	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2249	>	}
2250	>
2251	>	/**
2252	>	* Initializes table, using the size recorded in sizeCtl.
2253	>	*/
2254	>	private final Node<K,V>[] initTable() {
2255	>	Node<K,V>[] tab; int sc;
2256	>	while ((tab = table) == null || tab.length == 0) {
2257	>	if ((sc = sizeCtl) < 0)
2258	>	Thread.yield(); // lost initialization race; just spin
2259	>	else if (U.compareAndSetInt(this, SIZECTL, sc, -1)) {
2260	>	try {
2261	>	if ((tab = table) == null || tab.length == 0) {
2262	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2263	>	@SuppressWarnings("unchecked")
2264	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2265	>	table = tab = nt;
2266	>	sc = n - (n >>> 2);
2267	>	}
2268	>	} finally {
2269	>	sizeCtl = sc;
2270	>	}
2271	>	break;
2272	>	}
2273	>	}
2274	>	return tab;
2275	>	}
2276	>
2277	>	/**
2278	>	* Adds to count, and if table is too small and not already
2279	>	* resizing, initiates transfer. If already resizing, helps
2280	>	* perform transfer if work is available.  Rechecks occupancy
2281	>	* after a transfer to see if another resize is already needed
2282	>	* because resizings are lagging additions.
2283	>	*
2284	>	* @param x the count to add
2285	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2286	>	*/
2287	>	private final void addCount(long x, int check) {
2288	>	CounterCell[] cs; long b, s;
2289	>	if ((cs = counterCells) != null ||
2290	>	!U.compareAndSetLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2291	>	CounterCell c; long v; int m;
2292	>	boolean uncontended = true;
2293	>	if (cs == null || (m = cs.length - 1) < 0 ||
2294	>	(c = cs[ThreadLocalRandom.getProbe() & m]) == null ||
2295	>	!(uncontended =
2296	>	U.compareAndSetLong(c, CELLVALUE, v = c.value, v + x))) {
2297	>	fullAddCount(x, uncontended);
2298	>	return;
2299	>	}
2300	>	if (check <= 1)
2301	>	return;
2302	>	s = sumCount();
2303	>	}
2304	>	if (check >= 0) {
2305	>	Node<K,V>[] tab, nt; int n, sc;
2306	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2307	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2308	>	int rs = resizeStamp(n) << RESIZE_STAMP_SHIFT;
2309	>	if (sc < 0) {
2310	>	if (sc == rs + MAX_RESIZERS || sc == rs + 1 ||
2311	>	(nt = nextTable) == null || transferIndex <= 0)
2312	>	break;
2313	>	if (U.compareAndSetInt(this, SIZECTL, sc, sc + 1))
2314	>	transfer(tab, nt);
2315	>	}
2316	>	else if (U.compareAndSetInt(this, SIZECTL, sc, rs + 2))
2317	>	transfer(tab, null);
2318	>	s = sumCount();
2319	>	}
2320	>	}
2321	>	}
2322	>
2323	>	/**
2324	>	* Helps transfer if a resize is in progress.
2325	>	*/
2326	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2327	>	Node<K,V>[] nextTab; int sc;
2328	>	if (tab != null && (f instanceof ForwardingNode) &&
2329	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2330	>	int rs = resizeStamp(tab.length) << RESIZE_STAMP_SHIFT;
2331	>	while (nextTab == nextTable && table == tab &&
2332	>	(sc = sizeCtl) < 0) {
2333	>	if (sc == rs + MAX_RESIZERS || sc == rs + 1 ||
2334	>	transferIndex <= 0)
2335	>	break;
2336	>	if (U.compareAndSetInt(this, SIZECTL, sc, sc + 1)) {
2337	>	transfer(tab, nextTab);
2338	>	break;
2339	>	}
2340	>	}
2341	>	return nextTab;
2342	>	}
2343	>	return table;
2344	>	}
2345	>
2346	>	/**
2347	>	* Tries to presize table to accommodate the given number of elements.
2348	>	*
2349	>	* @param size number of elements (doesn't need to be perfectly accurate)
2350	>	*/
2351	>	private final void tryPresize(int size) {
2352	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2353	>	tableSizeFor(size + (size >>> 1) + 1);
2354	>	int sc;
2355	>	while ((sc = sizeCtl) >= 0) {
2356	>	Node<K,V>[] tab = table; int n;
2357	>	if (tab == null || (n = tab.length) == 0) {
2358	>	n = (sc > c) ? sc : c;
2359	>	if (U.compareAndSetInt(this, SIZECTL, sc, -1)) {
2360	>	try {
2361	>	if (table == tab) {
2362	>	@SuppressWarnings("unchecked")
2363	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2364	>	table = nt;
2365	>	sc = n - (n >>> 2);
2366	>	}
2367	>	} finally {
2368	>	sizeCtl = sc;
2369	>	}
2370	>	}
2371	>	}
2372	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2373	>	break;
2374	>	else if (tab == table) {
2375	>	int rs = resizeStamp(n);
2376	>	if (U.compareAndSetInt(this, SIZECTL, sc,
2377	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2378	>	transfer(tab, null);
2379	>	}
2380	>	}
2381	>	}
2382	>
2383	>	/**
2384	>	* Moves and/or copies the nodes in each bin to new table. See
2385	>	* above for explanation.
2386	>	*/
2387	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2388	>	int n = tab.length, stride;
2389	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2390	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2391	>	if (nextTab == null) {            // initiating
2392	>	try {
2393	>	@SuppressWarnings("unchecked")
2394	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2395	>	nextTab = nt;
2396	>	} catch (Throwable ex) {      // try to cope with OOME
2397	>	sizeCtl = Integer.MAX_VALUE;
2398	>	return;
2399	>	}
2400	>	nextTable = nextTab;
2401	>	transferIndex = n;
2402	>	}
2403	>	int nextn = nextTab.length;
2404	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2405	>	boolean advance = true;
2406	>	boolean finishing = false; // to ensure sweep before committing nextTab
2407	>	for (int i = 0, bound = 0;;) {
2408	>	Node<K,V> f; int fh;
2409	>	while (advance) {
2410	>	int nextIndex, nextBound;
2411	>	if (--i >= bound || finishing)
2412	>	advance = false;
2413	>	else if ((nextIndex = transferIndex) <= 0) {
2414	>	i = -1;
2415	>	advance = false;
2416	>	}
2417	>	else if (U.compareAndSetInt
2418	>	(this, TRANSFERINDEX, nextIndex,
2419	>	nextBound = (nextIndex > stride ?
2420	>	nextIndex - stride : 0))) {
2421	>	bound = nextBound;
2422	>	i = nextIndex - 1;
2423	>	advance = false;
2424	>	}
2425	>	}
2426	>	if (i < 0 || i >= n || i + n >= nextn) {
2427	>	int sc;
2428	>	if (finishing) {
2429	>	nextTable = null;
2430	>	table = nextTab;
2431	>	sizeCtl = (n << 1) - (n >>> 1);
2432	>	return;
2433	>	}
2434	>	if (U.compareAndSetInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2435	>	if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT)
2436	>	return;
2437	>	finishing = advance = true;
2438	>	i = n; // recheck before commit
2439	>	}
2440	>	}
2441	>	else if ((f = tabAt(tab, i)) == null)
2442	>	advance = casTabAt(tab, i, null, fwd);
2443	>	else if ((fh = f.hash) == MOVED)
2444	>	advance = true; // already processed
2445	>	else {
2446	>	synchronized (f) {
2447	>	if (tabAt(tab, i) == f) {
2448	>	Node<K,V> ln, hn;
2449	>	if (fh >= 0) {
2450	>	int runBit = fh & n;
2451	>	Node<K,V> lastRun = f;
2452	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2453	>	int b = p.hash & n;
2454	>	if (b != runBit) {
2455	>	runBit = b;
2456	>	lastRun = p;
2457	>	}
2458	>	}
2459	>	if (runBit == 0) {
2460	>	ln = lastRun;
2461	>	hn = null;
2462	>	}
2463	>	else {
2464	>	hn = lastRun;
2465	>	ln = null;
2466	>	}
2467	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2468	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2469	>	if ((ph & n) == 0)
2470	>	ln = new Node<K,V>(ph, pk, pv, ln);
2471	>	else
2472	>	hn = new Node<K,V>(ph, pk, pv, hn);
2473	>	}
2474	>	setTabAt(nextTab, i, ln);
2475	>	setTabAt(nextTab, i + n, hn);
2476	>	setTabAt(tab, i, fwd);
2477	>	advance = true;
2478	>	}
2479	>	else if (f instanceof TreeBin) {
2480	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2481	>	TreeNode<K,V> lo = null, loTail = null;
2482	>	TreeNode<K,V> hi = null, hiTail = null;
2483	>	int lc = 0, hc = 0;
2484	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2485	>	int h = e.hash;
2486	>	TreeNode<K,V> p = new TreeNode<K,V>
2487	>	(h, e.key, e.val, null, null);
2488	>	if ((h & n) == 0) {
2489	>	if ((p.prev = loTail) == null)
2490	>	lo = p;
2491	>	else
2492	>	loTail.next = p;
2493	>	loTail = p;
2494	>	++lc;
2495	>	}
2496	>	else {
2497	>	if ((p.prev = hiTail) == null)
2498	>	hi = p;
2499	>	else
2500	>	hiTail.next = p;
2501	>	hiTail = p;
2502	>	++hc;
2503	>	}
2504	>	}
2505	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2506	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2507	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2508	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2509	>	setTabAt(nextTab, i, ln);
2510	>	setTabAt(nextTab, i + n, hn);
2511	>	setTabAt(tab, i, fwd);
2512	>	advance = true;
2513	>	}
2514	>	else if (f instanceof ReservationNode)
2515	>	throw new IllegalStateException("Recursive update");
2516	>	}
2517	>	}
2518	>	}
2519	>	}
2520	>	}
2521	>
2522	>	/* ---------------- Counter support -------------- */
2523	>
2524	>	/**
2525	>	* A padded cell for distributing counts.  Adapted from LongAdder
2526	>	* and Striped64.  See their internal docs for explanation.
2527	>	*/
2528	>	@jdk.internal.vm.annotation.Contended static final class CounterCell {
2529	>	volatile long value;
2530	>	CounterCell(long x) { value = x; }
2531	>	}
2532	>
2533	>	final long sumCount() {
2534	>	CounterCell[] cs = counterCells;
2535	>	long sum = baseCount;
2536	>	if (cs != null) {
2537	>	for (CounterCell c : cs)
2538	>	if (c != null)
2539	>	sum += c.value;
2540	>	}
2541	>	return sum;
2542	>	}
2543	>
2544	>	// See LongAdder version for explanation
2545	>	private final void fullAddCount(long x, boolean wasUncontended) {
2546	>	int h;
2547	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2548	>	ThreadLocalRandom.localInit();      // force initialization
2549	>	h = ThreadLocalRandom.getProbe();
2550	>	wasUncontended = true;
2551	>	}
2552	>	boolean collide = false;                // True if last slot nonempty
2553	>	for (;;) {
2554	>	CounterCell[] cs; CounterCell c; int n; long v;
2555	>	if ((cs = counterCells) != null && (n = cs.length) > 0) {
2556	>	if ((c = cs[(n - 1) & h]) == null) {
2557	>	if (cellsBusy == 0) {            // Try to attach new Cell
2558	>	CounterCell r = new CounterCell(x); // Optimistic create
2559	>	if (cellsBusy == 0 &&
2560	>	U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
2561	>	boolean created = false;
2562	>	try {               // Recheck under lock
2563	>	CounterCell[] rs; int m, j;
2564	>	if ((rs = counterCells) != null &&
2565	>	(m = rs.length) > 0 &&
2566	>	rs[j = (m - 1) & h] == null) {
2567	>	rs[j] = r;
2568	>	created = true;
2569	>	}
2570	>	} finally {
2571	>	cellsBusy = 0;
2572	>	}
2573	>	if (created)
2574	>	break;
2575	>	continue;           // Slot is now non-empty
2576	>	}
2577	>	}
2578	>	collide = false;
2579	>	}
2580	>	else if (!wasUncontended)       // CAS already known to fail
2581	>	wasUncontended = true;      // Continue after rehash
2582	>	else if (U.compareAndSetLong(c, CELLVALUE, v = c.value, v + x))
2583	>	break;
2584	>	else if (counterCells != cs || n >= NCPU)
2585	>	collide = false;            // At max size or stale
2586	>	else if (!collide)
2587	>	collide = true;
2588	>	else if (cellsBusy == 0 &&
2589	>	U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
2590	>	try {
2591	>	if (counterCells == cs) // Expand table unless stale
2592	>	counterCells = Arrays.copyOf(cs, n << 1);
2593	>	} finally {
2594	>	cellsBusy = 0;
2595	>	}
2596	>	collide = false;
2597	>	continue;                   // Retry with expanded table
2598	>	}
2599	>	h = ThreadLocalRandom.advanceProbe(h);
2600	>	}
2601	>	else if (cellsBusy == 0 && counterCells == cs &&
2602	>	U.compareAndSetInt(this, CELLSBUSY, 0, 1)) {
2603	>	boolean init = false;
2604	>	try {                           // Initialize table
2605	>	if (counterCells == cs) {
2606	>	CounterCell[] rs = new CounterCell[2];
2607	>	rs[h & 1] = new CounterCell(x);
2608	>	counterCells = rs;
2609	>	init = true;
2610	>	}
2611	>	} finally {
2612	>	cellsBusy = 0;
2613	>	}
2614	>	if (init)
2615	>	break;
2616	>	}
2617	>	else if (U.compareAndSetLong(this, BASECOUNT, v = baseCount, v + x))
2618	>	break;                          // Fall back on using base
2619	>	}
2620	>	}
2621	>
2622	>	/* ---------------- Conversion from/to TreeBins -------------- */
2623	>
2624	>	/**
2625	>	* Replaces all linked nodes in bin at given index unless table is
2626	>	* too small, in which case resizes instead.
2627	>	*/
2628	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2629	>	Node<K,V> b; int n;
2630	>	if (tab != null) {
2631	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2632	>	tryPresize(n << 1);
2633	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2634	>	synchronized (b) {
2635	>	if (tabAt(tab, index) == b) {
2636	>	TreeNode<K,V> hd = null, tl = null;
2637	>	for (Node<K,V> e = b; e != null; e = e.next) {
2638	>	TreeNode<K,V> p =
2639	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2640	>	null, null);
2641	>	if ((p.prev = tl) == null)
2642	>	hd = p;
2643	>	else
2644	>	tl.next = p;
2645	>	tl = p;
2646	>	}
2647	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2648	>	}
2649	>	}
2650	>	}
2651	>	}
2652	>	}
2653	>
2654	>	/**
2655	>	* Returns a list of non-TreeNodes replacing those in given list.
2656	>	*/
2657	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2658	>	Node<K,V> hd = null, tl = null;
2659	>	for (Node<K,V> q = b; q != null; q = q.next) {
2660	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val);
2661	>	if (tl == null)
2662	>	hd = p;
2663	>	else
2664	>	tl.next = p;
2665	>	tl = p;
2666	>	}
2667	>	return hd;
2668	>	}
2669	>
2670	>	/* ---------------- TreeNodes -------------- */
2671	>
2672	>	/**
2673	>	* Nodes for use in TreeBins.
2674	>	*/
2675	>	static final class TreeNode<K,V> extends Node<K,V> {
2676	>	TreeNode<K,V> parent;  // red-black tree links
2677	>	TreeNode<K,V> left;
2678	>	TreeNode<K,V> right;
2679	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2680	>	boolean red;
2681	>
2682	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2683	>	TreeNode<K,V> parent) {
2684	>	super(hash, key, val, next);
2685	>	this.parent = parent;
2686	>	}
2687	>
2688	>	Node<K,V> find(int h, Object k) {
2689	>	return findTreeNode(h, k, null);
2690	>	}
2691
2692		/**
2693	<	* The table is rehashed when its size exceeds this threshold.
2694	<	* (The value of this field is always (int)(capacity *
196	<	* loadFactor).)
2693	>	* Returns the TreeNode (or null if not found) for the given key
2694	>	* starting at given root.
2695		*/
2696	<	private transient int threshold;
2696	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2697	>	if (k != null) {
2698	>	TreeNode<K,V> p = this;
2699	>	do {
2700	>	int ph, dir; K pk; TreeNode<K,V> q;
2701	>	TreeNode<K,V> pl = p.left, pr = p.right;
2702	>	if ((ph = p.hash) > h)
2703	>	p = pl;
2704	>	else if (ph < h)
2705	>	p = pr;
2706	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2707	>	return p;
2708	>	else if (pl == null)
2709	>	p = pr;
2710	>	else if (pr == null)
2711	>	p = pl;
2712	>	else if ((kc != null ||
2713	>	(kc = comparableClassFor(k)) != null) &&
2714	>	(dir = compareComparables(kc, k, pk)) != 0)
2715	>	p = (dir < 0) ? pl : pr;
2716	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2717	>	return q;
2718	>	else
2719	>	p = pl;
2720	>	} while (p != null);
2721	>	}
2722	>	return null;
2723	>	}
2724	>	}
2725	>
2726	>	/* ---------------- TreeBins -------------- */
2727	>
2728	>	/**
2729	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2730	>	* keys or values, but instead point to list of TreeNodes and
2731	>	* their root. They also maintain a parasitic read-write lock
2732	>	* forcing writers (who hold bin lock) to wait for readers (who do
2733	>	* not) to complete before tree restructuring operations.
2734	>	*/
2735	>	static final class TreeBin<K,V> extends Node<K,V> {
2736	>	TreeNode<K,V> root;
2737	>	volatile TreeNode<K,V> first;
2738	>	volatile Thread waiter;
2739	>	volatile int lockState;
2740	>	// values for lockState
2741	>	static final int WRITER = 1; // set while holding write lock
2742	>	static final int WAITER = 2; // set when waiting for write lock
2743	>	static final int READER = 4; // increment value for setting read lock
2744
2745		/**
2746	<	* The per-segment table
2746	>	* Tie-breaking utility for ordering insertions when equal
2747	>	* hashCodes and non-comparable. We don't require a total
2748	>	* order, just a consistent insertion rule to maintain
2749	>	* equivalence across rebalancings. Tie-breaking further than
2750	>	* necessary simplifies testing a bit.
2751		*/
2752	<	transient HashEntry[] table;
2752	>	static int tieBreakOrder(Object a, Object b) {
2753	>	int d;
2754	>	if (a == null || b == null ||
2755	>	(d = a.getClass().getName().
2756	>	compareTo(b.getClass().getName())) == 0)
2757	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2758	>	-1 : 1);
2759	>	return d;
2760	>	}
2761
2762		/**
2763	<	* The load factor for the hash table.  Even though this value
207	<	* is same for all segments, it is replicated to avoid needing
208	<	* links to outer object.
209	<	* @serial
2763	>	* Creates bin with initial set of nodes headed by b.
2764		*/
2765	<	private final float loadFactor;
2766	<
2767	<	Segment(int initialCapacity, float lf) {
2768	<	loadFactor = lf;
2769	<	setTable(new HashEntry[initialCapacity]);
2765	>	TreeBin(TreeNode<K,V> b) {
2766	>	super(TREEBIN, null, null);
2767	>	this.first = b;
2768	>	TreeNode<K,V> r = null;
2769	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2770	>	next = (TreeNode<K,V>)x.next;
2771	>	x.left = x.right = null;
2772	>	if (r == null) {
2773	>	x.parent = null;
2774	>	x.red = false;
2775	>	r = x;
2776	>	}
2777	>	else {
2778	>	K k = x.key;
2779	>	int h = x.hash;
2780	>	Class<?> kc = null;
2781	>	for (TreeNode<K,V> p = r;;) {
2782	>	int dir, ph;
2783	>	K pk = p.key;
2784	>	if ((ph = p.hash) > h)
2785	>	dir = -1;
2786	>	else if (ph < h)
2787	>	dir = 1;
2788	>	else if ((kc == null &&
2789	>	(kc = comparableClassFor(k)) == null) ||
2790	>	(dir = compareComparables(kc, k, pk)) == 0)
2791	>	dir = tieBreakOrder(k, pk);
2792	>	TreeNode<K,V> xp = p;
2793	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2794	>	x.parent = xp;
2795	>	if (dir <= 0)
2796	>	xp.left = x;
2797	>	else
2798	>	xp.right = x;
2799	>	r = balanceInsertion(r, x);
2800	>	break;
2801	>	}
2802	>	}
2803	>	}
2804	>	}
2805	>	this.root = r;
2806	>	assert checkInvariants(root);
2807		}
2808
2809		/**
2810	<	* Set table to new HashEntry array.
2811	<	* Call only while holding lock or in constructor.
2812	<	**/
2813	<	private void setTable(HashEntry[] newTable) {
2814	<	table = newTable;
224	<	threshold = (int)(newTable.length * loadFactor);
225	<	count = count; // write-volatile
2810	>	* Acquires write lock for tree restructuring.
2811	>	*/
2812	>	private final void lockRoot() {
2813	>	if (!U.compareAndSetInt(this, LOCKSTATE, 0, WRITER))
2814	>	contendedLock(); // offload to separate method
2815		}
2816
2817	<	/* Specialized implementations of map methods */
2817	>	/**
2818	>	* Releases write lock for tree restructuring.
2819	>	*/
2820	>	private final void unlockRoot() {
2821	>	lockState = 0;
2822	>	}
2823
2824	<	V get(K key, int hash) {
2825	<	if (count != 0) { // read-volatile
2826	<	HashEntry[] tab = table;
2827	<	int index = hash & (tab.length - 1);
2828	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
2829	<	while (e != null) {
2830	<	if (e.hash == hash && key.equals(e.key))
2831	<	return e.value;
2832	<	e = e.next;
2824	>	/**
2825	>	* Possibly blocks awaiting root lock.
2826	>	*/
2827	>	private final void contendedLock() {
2828	>	boolean waiting = false;
2829	>	for (int s;;) {
2830	>	if (((s = lockState) & ~WAITER) == 0) {
2831	>	if (U.compareAndSetInt(this, LOCKSTATE, s, WRITER)) {
2832	>	if (waiting)
2833	>	waiter = null;
2834	>	return;
2835	>	}
2836		}
2837	+	else if ((s & WAITER) == 0) {
2838	+	if (U.compareAndSetInt(this, LOCKSTATE, s, s | WAITER)) {
2839	+	waiting = true;
2840	+	waiter = Thread.currentThread();
2841	+	}
2842	+	}
2843	+	else if (waiting)
2844	+	LockSupport.park(this);
2845		}
241	–	return null;
2846		}
2847
2848	<	boolean containsKey(Object key, int hash) {
2849	<	if (count != 0) { // read-volatile
2850	<	HashEntry[] tab = table;
2851	<	int index = hash & (tab.length - 1);
2852	<	HashEntry<K,V> e = (HashEntry<K,V>) tab[index];
2853	<	while (e != null) {
2854	<	if (e.hash == hash && key.equals(e.key))
2855	<	return true;
2856	<	e = e.next;
2848	>	/**
2849	>	* Returns matching node or null if none. Tries to search
2850	>	* using tree comparisons from root, but continues linear
2851	>	* search when lock not available.
2852	>	*/
2853	>	final Node<K,V> find(int h, Object k) {
2854	>	if (k != null) {
2855	>	for (Node<K,V> e = first; e != null; ) {
2856	>	int s; K ek;
2857	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2858	>	if (e.hash == h &&
2859	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2860	>	return e;
2861	>	e = e.next;
2862	>	}
2863	>	else if (U.compareAndSetInt(this, LOCKSTATE, s,
2864	>	s + READER)) {
2865	>	TreeNode<K,V> r, p;
2866	>	try {
2867	>	p = ((r = root) == null ? null :
2868	>	r.findTreeNode(h, k, null));
2869	>	} finally {
2870	>	Thread w;
2871	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2872	>	(READER|WAITER) && (w = waiter) != null)
2873	>	LockSupport.unpark(w);
2874	>	}
2875	>	return p;
2876	>	}
2877		}
2878		}
2879	<	return false;
2879	>	return null;
2880		}
2881
2882	<	boolean containsValue(Object value) {
2883	<	if (count != 0) { // read-volatile
2884	<	HashEntry[] tab = table;
2885	<	int len = tab.length;
2886	<	for (int i = 0 ; i < len; i++)
2887	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i] ; e != null ; e = e.next)
2888	<	if (value.equals(e.value))
2889	<	return true;
2882	>	/**
2883	>	* Finds or adds a node.
2884	>	* @return null if added
2885	>	*/
2886	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2887	>	Class<?> kc = null;
2888	>	boolean searched = false;
2889	>	for (TreeNode<K,V> p = root;;) {
2890	>	int dir, ph; K pk;
2891	>	if (p == null) {
2892	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2893	>	break;
2894	>	}
2895	>	else if ((ph = p.hash) > h)
2896	>	dir = -1;
2897	>	else if (ph < h)
2898	>	dir = 1;
2899	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2900	>	return p;
2901	>	else if ((kc == null &&
2902	>	(kc = comparableClassFor(k)) == null) ||
2903	>	(dir = compareComparables(kc, k, pk)) == 0) {
2904	>	if (!searched) {
2905	>	TreeNode<K,V> q, ch;
2906	>	searched = true;
2907	>	if (((ch = p.left) != null &&
2908	>	(q = ch.findTreeNode(h, k, kc)) != null) ||
2909	>	((ch = p.right) != null &&
2910	>	(q = ch.findTreeNode(h, k, kc)) != null))
2911	>	return q;
2912	>	}
2913	>	dir = tieBreakOrder(k, pk);
2914	>	}
2915	>
2916	>	TreeNode<K,V> xp = p;
2917	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2918	>	TreeNode<K,V> x, f = first;
2919	>	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2920	>	if (f != null)
2921	>	f.prev = x;
2922	>	if (dir <= 0)
2923	>	xp.left = x;
2924	>	else
2925	>	xp.right = x;
2926	>	if (!xp.red)
2927	>	x.red = true;
2928	>	else {
2929	>	lockRoot();
2930	>	try {
2931	>	root = balanceInsertion(root, x);
2932	>	} finally {
2933	>	unlockRoot();
2934	>	}
2935	>	}
2936	>	break;
2937	>	}
2938		}
2939	<	return false;
2939	>	assert checkInvariants(root);
2940	>	return null;
2941		}
2942
2943	<	V put(K key, int hash, V value, boolean onlyIfAbsent) {
2944	<	lock();
2943	>	/**
2944	>	* Removes the given node, that must be present before this
2945	>	* call.  This is messier than typical red-black deletion code
2946	>	* because we cannot swap the contents of an interior node
2947	>	* with a leaf successor that is pinned by "next" pointers
2948	>	* that are accessible independently of lock. So instead we
2949	>	* swap the tree linkages.
2950	>	*
2951	>	* @return true if now too small, so should be untreeified
2952	>	*/
2953	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2954	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2955	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2956	>	TreeNode<K,V> r, rl;
2957	>	if (pred == null)
2958	>	first = next;
2959	>	else
2960	>	pred.next = next;
2961	>	if (next != null)
2962	>	next.prev = pred;
2963	>	if (first == null) {
2964	>	root = null;
2965	>	return true;
2966	>	}
2967	>	if ((r = root) == null || r.right == null || // too small
2968	>	(rl = r.left) == null || rl.left == null)
2969	>	return true;
2970	>	lockRoot();
2971		try {
2972	<	int c = count;
2973	<	HashEntry[] tab = table;
2974	<	int index = hash & (tab.length - 1);
2975	<	HashEntry<K,V> first = (HashEntry<K,V>) tab[index];
2976	<
2977	<	for (HashEntry<K,V> e = first; e != null; e = (HashEntry<K,V>) e.next) {
2978	<	if (e.hash == hash && key.equals(e.key)) {
2979	<	V oldValue = e.value;
2980	<	if (!onlyIfAbsent)
2981	<	e.value = value;
2982	<	count = c; // write-volatile
2983	<	return oldValue;
2972	>	TreeNode<K,V> replacement;
2973	>	TreeNode<K,V> pl = p.left;
2974	>	TreeNode<K,V> pr = p.right;
2975	>	if (pl != null && pr != null) {
2976	>	TreeNode<K,V> s = pr, sl;
2977	>	while ((sl = s.left) != null) // find successor
2978	>	s = sl;
2979	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2980	>	TreeNode<K,V> sr = s.right;
2981	>	TreeNode<K,V> pp = p.parent;
2982	>	if (s == pr) { // p was s's direct parent
2983	>	p.parent = s;
2984	>	s.right = p;
2985	>	}
2986	>	else {
2987	>	TreeNode<K,V> sp = s.parent;
2988	>	if ((p.parent = sp) != null) {
2989	>	if (s == sp.left)
2990	>	sp.left = p;
2991	>	else
2992	>	sp.right = p;
2993	>	}
2994	>	if ((s.right = pr) != null)
2995	>	pr.parent = s;
2996	>	}
2997	>	p.left = null;
2998	>	if ((p.right = sr) != null)
2999	>	sr.parent = p;
3000	>	if ((s.left = pl) != null)
3001	>	pl.parent = s;
3002	>	if ((s.parent = pp) == null)
3003	>	r = s;
3004	>	else if (p == pp.left)
3005	>	pp.left = s;
3006	>	else
3007	>	pp.right = s;
3008	>	if (sr != null)
3009	>	replacement = sr;
3010	>	else
3011	>	replacement = p;
3012	>	}
3013	>	else if (pl != null)
3014	>	replacement = pl;
3015	>	else if (pr != null)
3016	>	replacement = pr;
3017	>	else
3018	>	replacement = p;
3019	>	if (replacement != p) {
3020	>	TreeNode<K,V> pp = replacement.parent = p.parent;
3021	>	if (pp == null)
3022	>	r = replacement;
3023	>	else if (p == pp.left)
3024	>	pp.left = replacement;
3025	>	else
3026	>	pp.right = replacement;
3027	>	p.left = p.right = p.parent = null;
3028	>	}
3029	>
3030	>	root = (p.red) ? r : balanceDeletion(r, replacement);
3031	>
3032	>	if (p == replacement) {  // detach pointers
3033	>	TreeNode<K,V> pp;
3034	>	if ((pp = p.parent) != null) {
3035	>	if (p == pp.left)
3036	>	pp.left = null;
3037	>	else if (p == pp.right)
3038	>	pp.right = null;
3039	>	p.parent = null;
3040		}
3041		}
3042	+	} finally {
3043	+	unlockRoot();
3044	+	}
3045	+	assert checkInvariants(root);
3046	+	return false;
3047	+	}
3048	+
3049	+	/* ------------------------------------------------------------ */
3050	+	// Red-black tree methods, all adapted from CLR
3051
3052	<	tab[index] = new HashEntry<K,V>(hash, key, value, first);
3053	<	++c;
3054	<	count = c; // write-volatile
3055	<	if (c > threshold)
3056	<	setTable(rehash(tab));
3057	<	return null;
3058	<	}
3059	<	finally {
3060	<	unlock();
3052	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3053	>	TreeNode<K,V> p) {
3054	>	TreeNode<K,V> r, pp, rl;
3055	>	if (p != null && (r = p.right) != null) {
3056	>	if ((rl = p.right = r.left) != null)
3057	>	rl.parent = p;
3058	>	if ((pp = r.parent = p.parent) == null)
3059	>	(root = r).red = false;
3060	>	else if (pp.left == p)
3061	>	pp.left = r;
3062	>	else
3063	>	pp.right = r;
3064	>	r.left = p;
3065	>	p.parent = r;
3066		}
3067	+	return root;
3068		}
3069
3070	<	private HashEntry[] rehash(HashEntry[] oldTable) {
3071	<	int oldCapacity = oldTable.length;
3072	<	if (oldCapacity >= MAXIMUM_CAPACITY)
3073	<	return oldTable;
3074	<
3075	<	/*
3076	<	* Reclassify nodes in each list to new Map.  Because we are
3077	<	* using power-of-two expansion, the elements from each bin
3078	<	* must either stay at same index, or move with a power of two
3079	<	* offset. We eliminate unnecessary node creation by catching
3080	<	* cases where old nodes can be reused because their next
3081	<	* fields won't change. Statistically, at the default
3082	<	* threshhold, only about one-sixth of them need cloning when
3083	<	* a table doubles. The nodes they replace will be garbage
3084	<	* collectable as soon as they are no longer referenced by any
3085	<	* reader thread that may be in the midst of traversing table
3086	<	* right now.
317	<	*/
318	<
319	<	HashEntry[] newTable = new HashEntry[oldCapacity << 1];
320	<	int sizeMask = newTable.length - 1;
321	<	for (int i = 0; i < oldCapacity ; i++) {
322	<	// We need to guarantee that any existing reads of old Map can
323	<	//  proceed. So we cannot yet null out each bin.
324	<	HashEntry<K,V> e = (HashEntry<K,V>)oldTable[i];
325	<
326	<	if (e != null) {
327	<	HashEntry<K,V> next = e.next;
328	<	int idx = e.hash & sizeMask;
329	<
330	<	//  Single node on list
331	<	if (next == null)
332	<	newTable[idx] = e;
3070	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3071	>	TreeNode<K,V> p) {
3072	>	TreeNode<K,V> l, pp, lr;
3073	>	if (p != null && (l = p.left) != null) {
3074	>	if ((lr = p.left = l.right) != null)
3075	>	lr.parent = p;
3076	>	if ((pp = l.parent = p.parent) == null)
3077	>	(root = l).red = false;
3078	>	else if (pp.right == p)
3079	>	pp.right = l;
3080	>	else
3081	>	pp.left = l;
3082	>	l.right = p;
3083	>	p.parent = l;
3084	>	}
3085	>	return root;
3086	>	}
3087
3088	+	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3089	+	TreeNode<K,V> x) {
3090	+	x.red = true;
3091	+	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3092	+	if ((xp = x.parent) == null) {
3093	+	x.red = false;
3094	+	return x;
3095	+	}
3096	+	else if (!xp.red || (xpp = xp.parent) == null)
3097	+	return root;
3098	+	if (xp == (xppl = xpp.left)) {
3099	+	if ((xppr = xpp.right) != null && xppr.red) {
3100	+	xppr.red = false;
3101	+	xp.red = false;
3102	+	xpp.red = true;
3103	+	x = xpp;
3104	+	}
3105		else {
3106	<	// Reuse trailing consecutive sequence at same slot
3107	<	HashEntry<K,V> lastRun = e;
3108	<	int lastIdx = idx;
3109	<	for (HashEntry<K,V> last = next;
3110	<	last != null;
3111	<	last = last.next) {
3112	<	int k = last.hash & sizeMask;
3113	<	if (k != lastIdx) {
3114	<	lastIdx = k;
344	<	lastRun = last;
3106	>	if (x == xp.right) {
3107	>	root = rotateLeft(root, x = xp);
3108	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3109	>	}
3110	>	if (xp != null) {
3111	>	xp.red = false;
3112	>	if (xpp != null) {
3113	>	xpp.red = true;
3114	>	root = rotateRight(root, xpp);
3115		}
3116		}
3117	<	newTable[lastIdx] = lastRun;
3117	>	}
3118	>	}
3119	>	else {
3120	>	if (xppl != null && xppl.red) {
3121	>	xppl.red = false;
3122	>	xp.red = false;
3123	>	xpp.red = true;
3124	>	x = xpp;
3125	>	}
3126	>	else {
3127	>	if (x == xp.left) {
3128	>	root = rotateRight(root, x = xp);
3129	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3130	>	}
3131	>	if (xp != null) {
3132	>	xp.red = false;
3133	>	if (xpp != null) {
3134	>	xpp.red = true;
3135	>	root = rotateLeft(root, xpp);
3136	>	}
3137	>	}
3138	>	}
3139	>	}
3140	>	}
3141	>	}
3142
3143	<	// Clone all remaining nodes
3144	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
3145	<	int k = p.hash & sizeMask;
3146	<	newTable[k] = new HashEntry<K,V>(p.hash,
3147	<	p.key,
3148	<	p.value,
3149	<	(HashEntry<K,V>) newTable[k]);
3143	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3144	>	TreeNode<K,V> x) {
3145	>	for (TreeNode<K,V> xp, xpl, xpr;;) {
3146	>	if (x == null || x == root)
3147	>	return root;
3148	>	else if ((xp = x.parent) == null) {
3149	>	x.red = false;
3150	>	return x;
3151	>	}
3152	>	else if (x.red) {
3153	>	x.red = false;
3154	>	return root;
3155	>	}
3156	>	else if ((xpl = xp.left) == x) {
3157	>	if ((xpr = xp.right) != null && xpr.red) {
3158	>	xpr.red = false;
3159	>	xp.red = true;
3160	>	root = rotateLeft(root, xp);
3161	>	xpr = (xp = x.parent) == null ? null : xp.right;
3162	>	}
3163	>	if (xpr == null)
3164	>	x = xp;
3165	>	else {
3166	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3167	>	if ((sr == null || !sr.red) &&
3168	>	(sl == null || !sl.red)) {
3169	>	xpr.red = true;
3170	>	x = xp;
3171	>	}
3172	>	else {
3173	>	if (sr == null || !sr.red) {
3174	>	if (sl != null)
3175	>	sl.red = false;
3176	>	xpr.red = true;
3177	>	root = rotateRight(root, xpr);
3178	>	xpr = (xp = x.parent) == null ?
3179	>	null : xp.right;
3180	>	}
3181	>	if (xpr != null) {
3182	>	xpr.red = (xp == null) ? false : xp.red;
3183	>	if ((sr = xpr.right) != null)
3184	>	sr.red = false;
3185	>	}
3186	>	if (xp != null) {
3187	>	xp.red = false;
3188	>	root = rotateLeft(root, xp);
3189	>	}
3190	>	x = root;
3191	>	}
3192	>	}
3193	>	}
3194	>	else { // symmetric
3195	>	if (xpl != null && xpl.red) {
3196	>	xpl.red = false;
3197	>	xp.red = true;
3198	>	root = rotateRight(root, xp);
3199	>	xpl = (xp = x.parent) == null ? null : xp.left;
3200	>	}
3201	>	if (xpl == null)
3202	>	x = xp;
3203	>	else {
3204	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3205	>	if ((sl == null || !sl.red) &&
3206	>	(sr == null || !sr.red)) {
3207	>	xpl.red = true;
3208	>	x = xp;
3209	>	}
3210	>	else {
3211	>	if (sl == null || !sl.red) {
3212	>	if (sr != null)
3213	>	sr.red = false;
3214	>	xpl.red = true;
3215	>	root = rotateLeft(root, xpl);
3216	>	xpl = (xp = x.parent) == null ?
3217	>	null : xp.left;
3218	>	}
3219	>	if (xpl != null) {
3220	>	xpl.red = (xp == null) ? false : xp.red;
3221	>	if ((sl = xpl.left) != null)
3222	>	sl.red = false;
3223	>	}
3224	>	if (xp != null) {
3225	>	xp.red = false;
3226	>	root = rotateRight(root, xp);
3227	>	}
3228	>	x = root;
3229		}
3230		}
3231		}
3232		}
360	–	return newTable;
3233		}
3234
3235		/**
3236	<	* Remove; match on key only if value null, else match both.
3236	>	* Checks invariants recursively for the tree of Nodes rooted at t.
3237		*/
3238	<	V remove(Object key, int hash, Object value) {
3239	<	lock();
3238	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3239	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3240	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3241	>	if (tb != null && tb.next != t)
3242	>	return false;
3243	>	if (tn != null && tn.prev != t)
3244	>	return false;
3245	>	if (tp != null && t != tp.left && t != tp.right)
3246	>	return false;
3247	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3248	>	return false;
3249	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3250	>	return false;
3251	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3252	>	return false;
3253	>	if (tl != null && !checkInvariants(tl))
3254	>	return false;
3255	>	if (tr != null && !checkInvariants(tr))
3256	>	return false;
3257	>	return true;
3258	>	}
3259	>
3260	>	private static final Unsafe U = Unsafe.getUnsafe();
3261	>	private static final long LOCKSTATE;
3262	>	static {
3263		try {
3264	<	int c = count;
3265	<	HashEntry[] tab = table;
3266	<	int index = hash & (tab.length - 1);
3267	<	HashEntry<K,V> first = (HashEntry<K,V>)tab[index];
3264	>	LOCKSTATE = U.objectFieldOffset
3265	>	(TreeBin.class.getDeclaredField("lockState"));
3266	>	} catch (ReflectiveOperationException e) {
3267	>	throw new ExceptionInInitializerError(e);
3268	>	}
3269	>	}
3270	>	}
3271
3272	<	HashEntry<K,V> e = first;
375	<	for (;;) {
376	<	if (e == null)
377	<	return null;
378	<	if (e.hash == hash && key.equals(e.key))
379	<	break;
380	<	e = e.next;
381	<	}
3272	>	/* ----------------Table Traversal -------------- */
3273
3274	<	V oldValue = e.value;
3275	<	if (value != null && !value.equals(oldValue))
3276	<	return null;
3274	>	/**
3275	>	* Records the table, its length, and current traversal index for a
3276	>	* traverser that must process a region of a forwarded table before
3277	>	* proceeding with current table.
3278	>	*/
3279	>	static final class TableStack<K,V> {
3280	>	int length;
3281	>	int index;
3282	>	Node<K,V>[] tab;
3283	>	TableStack<K,V> next;
3284	>	}
3285
3286	<	// All entries following removed node can stay in list, but
3287	<	// all preceeding ones need to be cloned.
3288	<	HashEntry<K,V> newFirst = e.next;
3289	<	for (HashEntry<K,V> p = first; p != e; p = p.next)
3290	<	newFirst = new HashEntry<K,V>(p.hash, p.key,
3291	<	p.value, newFirst);
3292	<	tab[index] = newFirst;
3293	<	count = c-1; // write-volatile
3294	<	return oldValue;
3295	<	}
3296	<	finally {
3297	<	unlock();
3298	<	}
3286	>	/**
3287	>	* Encapsulates traversal for methods such as containsValue; also
3288	>	* serves as a base class for other iterators and spliterators.
3289	>	*
3290	>	* Method advance visits once each still-valid node that was
3291	>	* reachable upon iterator construction. It might miss some that
3292	>	* were added to a bin after the bin was visited, which is OK wrt
3293	>	* consistency guarantees. Maintaining this property in the face
3294	>	* of possible ongoing resizes requires a fair amount of
3295	>	* bookkeeping state that is difficult to optimize away amidst
3296	>	* volatile accesses.  Even so, traversal maintains reasonable
3297	>	* throughput.
3298	>	*
3299	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3300	>	* However, if the table has been resized, then all future steps
3301	>	* must traverse both the bin at the current index as well as at
3302	>	* (index + baseSize); and so on for further resizings. To
3303	>	* paranoically cope with potential sharing by users of iterators
3304	>	* across threads, iteration terminates if a bounds checks fails
3305	>	* for a table read.
3306	>	*/
3307	>	static class Traverser<K,V> {
3308	>	Node<K,V>[] tab;        // current table; updated if resized
3309	>	Node<K,V> next;         // the next entry to use
3310	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3311	>	int index;              // index of bin to use next
3312	>	int baseIndex;          // current index of initial table
3313	>	int baseLimit;          // index bound for initial table
3314	>	final int baseSize;     // initial table size
3315	>
3316	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3317	>	this.tab = tab;
3318	>	this.baseSize = size;
3319	>	this.baseIndex = this.index = index;
3320	>	this.baseLimit = limit;
3321	>	this.next = null;
3322		}
3323
3324	<	void clear() {
3325	<	lock();
3326	<	try {
3327	<	HashEntry[] tab = table;
3328	<	for (int i = 0; i < tab.length ; i++)
3329	<	tab[i] = null;
3330	<	count = 0; // write-volatile
3324	>	/**
3325	>	* Advances if possible, returning next valid node, or null if none.
3326	>	*/
3327	>	final Node<K,V> advance() {
3328	>	Node<K,V> e;
3329	>	if ((e = next) != null)
3330	>	e = e.next;
3331	>	for (;;) {
3332	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3333	>	if (e != null)
3334	>	return next = e;
3335	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3336	>	(n = t.length) <= (i = index) || i < 0)
3337	>	return next = null;
3338	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3339	>	if (e instanceof ForwardingNode) {
3340	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3341	>	e = null;
3342	>	pushState(t, i, n);
3343	>	continue;
3344	>	}
3345	>	else if (e instanceof TreeBin)
3346	>	e = ((TreeBin<K,V>)e).first;
3347	>	else
3348	>	e = null;
3349	>	}
3350	>	if (stack != null)
3351	>	recoverState(n);
3352	>	else if ((index = i + baseSize) >= n)
3353	>	index = ++baseIndex; // visit upper slots if present
3354		}
3355	<	finally {
3356	<	unlock();
3355	>	}
3356	>
3357	>	/**
3358	>	* Saves traversal state upon encountering a forwarding node.
3359	>	*/
3360	>	private void pushState(Node<K,V>[] t, int i, int n) {
3361	>	TableStack<K,V> s = spare;  // reuse if possible
3362	>	if (s != null)
3363	>	spare = s.next;
3364	>	else
3365	>	s = new TableStack<K,V>();
3366	>	s.tab = t;
3367	>	s.length = n;
3368	>	s.index = i;
3369	>	s.next = stack;
3370	>	stack = s;
3371	>	}
3372	>
3373	>	/**
3374	>	* Possibly pops traversal state.
3375	>	*
3376	>	* @param n length of current table
3377	>	*/
3378	>	private void recoverState(int n) {
3379	>	TableStack<K,V> s; int len;
3380	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3381	>	n = len;
3382	>	index = s.index;
3383	>	tab = s.tab;
3384	>	s.tab = null;
3385	>	TableStack<K,V> next = s.next;
3386	>	s.next = spare; // save for reuse
3387	>	stack = next;
3388	>	spare = s;
3389		}
3390	+	if (s == null && (index += baseSize) >= n)
3391	+	index = ++baseIndex;
3392		}
3393		}
3394
3395		/**
3396	<	* ConcurrentReaderHashMap list entry.
3396	>	* Base of key, value, and entry Iterators. Adds fields to
3397	>	* Traverser to support iterator.remove.
3398		*/
3399	<	private static class HashEntry<K,V> implements Entry<K,V> {
3400	<	private final K key;
3401	<	private V value;
3402	<	private final int hash;
3403	<	private final HashEntry<K,V> next;
3399	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3400	>	final ConcurrentHashMap<K,V> map;
3401	>	Node<K,V> lastReturned;
3402	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3403	>	ConcurrentHashMap<K,V> map) {
3404	>	super(tab, size, index, limit);
3405	>	this.map = map;
3406	>	advance();
3407	>	}
3408
3409	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
3410	<	this.value = value;
3411	<	this.hash = hash;
3412	<	this.key = key;
3413	<	this.next = next;
3409	>	public final boolean hasNext() { return next != null; }
3410	>	public final boolean hasMoreElements() { return next != null; }
3411	>
3412	>	public final void remove() {
3413	>	Node<K,V> p;
3414	>	if ((p = lastReturned) == null)
3415	>	throw new IllegalStateException();
3416	>	lastReturned = null;
3417	>	map.replaceNode(p.key, null, null);
3418	>	}
3419	>	}
3420	>
3421	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3422	>	implements Iterator<K>, Enumeration<K> {
3423	>	KeyIterator(Node<K,V>[] tab, int size, int index, int limit,
3424	>	ConcurrentHashMap<K,V> map) {
3425	>	super(tab, size, index, limit, map);
3426	>	}
3427	>
3428	>	public final K next() {
3429	>	Node<K,V> p;
3430	>	if ((p = next) == null)
3431	>	throw new NoSuchElementException();
3432	>	K k = p.key;
3433	>	lastReturned = p;
3434	>	advance();
3435	>	return k;
3436	>	}
3437	>
3438	>	public final K nextElement() { return next(); }
3439	>	}
3440	>
3441	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3442	>	implements Iterator<V>, Enumeration<V> {
3443	>	ValueIterator(Node<K,V>[] tab, int size, int index, int limit,
3444	>	ConcurrentHashMap<K,V> map) {
3445	>	super(tab, size, index, limit, map);
3446		}
3447
3448	<	public K getKey() {
3449	<	return key;
3448	>	public final V next() {
3449	>	Node<K,V> p;
3450	>	if ((p = next) == null)
3451	>	throw new NoSuchElementException();
3452	>	V v = p.val;
3453	>	lastReturned = p;
3454	>	advance();
3455	>	return v;
3456		}
3457
3458	<	public V getValue() {
3459	<	return value;
3458	>	public final V nextElement() { return next(); }
3459	>	}
3460	>
3461	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3462	>	implements Iterator<Map.Entry<K,V>> {
3463	>	EntryIterator(Node<K,V>[] tab, int size, int index, int limit,
3464	>	ConcurrentHashMap<K,V> map) {
3465	>	super(tab, size, index, limit, map);
3466	>	}
3467	>
3468	>	public final Map.Entry<K,V> next() {
3469	>	Node<K,V> p;
3470	>	if ((p = next) == null)
3471	>	throw new NoSuchElementException();
3472	>	K k = p.key;
3473	>	V v = p.val;
3474	>	lastReturned = p;
3475	>	advance();
3476	>	return new MapEntry<K,V>(k, v, map);
3477		}
3478	+	}
3479
3480	<	public V setValue(V newValue) {
3481	<	// We aren't required to, and don't provide any
3482	<	// visibility barriers for setting value.
3483	<	if (newValue == null)
3484	<	throw new NullPointerException();
3485	<	V oldValue = this.value;
3486	<	this.value = newValue;
3487	<	return oldValue;
3480	>	/**
3481	>	* Exported Entry for EntryIterator.
3482	>	*/
3483	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3484	>	final K key; // non-null
3485	>	V val;       // non-null
3486	>	final ConcurrentHashMap<K,V> map;
3487	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3488	>	this.key = key;
3489	>	this.val = val;
3490	>	this.map = map;
3491	>	}
3492	>	public K getKey()        { return key; }
3493	>	public V getValue()      { return val; }
3494	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3495	>	public String toString() {
3496	>	return Helpers.mapEntryToString(key, val);
3497		}
3498
3499		public boolean equals(Object o) {
3500	<	if (!(o instanceof Entry))
3500	>	Object k, v; Map.Entry<?,?> e;
3501	>	return ((o instanceof Map.Entry) &&
3502	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3503	>	(v = e.getValue()) != null &&
3504	>	(k == key || k.equals(key)) &&
3505	>	(v == val || v.equals(val)));
3506	>	}
3507	>
3508	>	/**
3509	>	* Sets our entry's value and writes through to the map. The
3510	>	* value to return is somewhat arbitrary here. Since we do not
3511	>	* necessarily track asynchronous changes, the most recent
3512	>	* "previous" value could be different from what we return (or
3513	>	* could even have been removed, in which case the put will
3514	>	* re-establish). We do not and cannot guarantee more.
3515	>	*/
3516	>	public V setValue(V value) {
3517	>	if (value == null) throw new NullPointerException();
3518	>	V v = val;
3519	>	val = value;
3520	>	map.put(key, value);
3521	>	return v;
3522	>	}
3523	>	}
3524	>
3525	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3526	>	implements Spliterator<K> {
3527	>	long est;               // size estimate
3528	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3529	>	long est) {
3530	>	super(tab, size, index, limit);
3531	>	this.est = est;
3532	>	}
3533	>
3534	>	public KeySpliterator<K,V> trySplit() {
3535	>	int i, f, h;
3536	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3537	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3538	>	f, est >>>= 1);
3539	>	}
3540	>
3541	>	public void forEachRemaining(Consumer<? super K> action) {
3542	>	if (action == null) throw new NullPointerException();
3543	>	for (Node<K,V> p; (p = advance()) != null;)
3544	>	action.accept(p.key);
3545	>	}
3546	>
3547	>	public boolean tryAdvance(Consumer<? super K> action) {
3548	>	if (action == null) throw new NullPointerException();
3549	>	Node<K,V> p;
3550	>	if ((p = advance()) == null)
3551		return false;
3552	<	Entry<K,V> e = (Entry<K,V>)o;
3553	<	return (key.equals(e.getKey()) && value.equals(e.getValue()));
3552	>	action.accept(p.key);
3553	>	return true;
3554		}
3555
3556	<	public int hashCode() {
3557	<	return  key.hashCode() ^ value.hashCode();
3556	>	public long estimateSize() { return est; }
3557	>
3558	>	public int characteristics() {
3559	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3560	>	Spliterator.NONNULL;
3561	>	}
3562	>	}
3563	>
3564	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3565	>	implements Spliterator<V> {
3566	>	long est;               // size estimate
3567	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3568	>	long est) {
3569	>	super(tab, size, index, limit);
3570	>	this.est = est;
3571		}
3572
3573	<	public String toString() {
3574	<	return key + "=" + value;
3573	>	public ValueSpliterator<K,V> trySplit() {
3574	>	int i, f, h;
3575	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3576	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3577	>	f, est >>>= 1);
3578	>	}
3579	>
3580	>	public void forEachRemaining(Consumer<? super V> action) {
3581	>	if (action == null) throw new NullPointerException();
3582	>	for (Node<K,V> p; (p = advance()) != null;)
3583	>	action.accept(p.val);
3584	>	}
3585	>
3586	>	public boolean tryAdvance(Consumer<? super V> action) {
3587	>	if (action == null) throw new NullPointerException();
3588	>	Node<K,V> p;
3589	>	if ((p = advance()) == null)
3590	>	return false;
3591	>	action.accept(p.val);
3592	>	return true;
3593	>	}
3594	>
3595	>	public long estimateSize() { return est; }
3596	>
3597	>	public int characteristics() {
3598	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3599		}
3600		}
3601
3602	+	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3603	+	implements Spliterator<Map.Entry<K,V>> {
3604	+	final ConcurrentHashMap<K,V> map; // To export MapEntry
3605	+	long est;               // size estimate
3606	+	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3607	+	long est, ConcurrentHashMap<K,V> map) {
3608	+	super(tab, size, index, limit);
3609	+	this.map = map;
3610	+	this.est = est;
3611	+	}
3612
3613	<	/* ---------------- Public operations -------------- */
3613	>	public EntrySpliterator<K,V> trySplit() {
3614	>	int i, f, h;
3615	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3616	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3617	>	f, est >>>= 1, map);
3618	>	}
3619
3620	<	/**
3621	<	* Constructs a new, empty map with the specified initial
3622	<	* capacity and the specified load factor.
3623	<	*
3624	<	* @param initialCapacity the initial capacity.  The actual
474	<	* initial capacity is rounded up to the nearest power of two.
475	<	* @param loadFactor  the load factor threshold, used to control resizing.
476	<	* @param segments the number of concurrently accessible segments. the
477	<	* actual number of segments is rounded to the next power of two.
478	<	* @throws IllegalArgumentException if the initial capacity is
479	<	* negative or the load factor or number of segments are
480	<	* nonpositive.
481	<	*/
482	<	public ConcurrentHashMap(int initialCapacity,
483	<	float loadFactor, int segments) {
484	<	if (!(loadFactor > 0) || initialCapacity < 0 || segments <= 0)
485	<	throw new IllegalArgumentException();
3620	>	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3621	>	if (action == null) throw new NullPointerException();
3622	>	for (Node<K,V> p; (p = advance()) != null; )
3623	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3624	>	}
3625
3626	<	// Find power-of-two sizes best matching arguments
3627	<	int sshift = 0;
3628	<	int ssize = 1;
3629	<	while (ssize < segments) {
3630	<	++sshift;
3631	<	ssize <<= 1;
3626	>	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3627	>	if (action == null) throw new NullPointerException();
3628	>	Node<K,V> p;
3629	>	if ((p = advance()) == null)
3630	>	return false;
3631	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3632	>	return true;
3633		}
494	–	segmentShift = 32 - sshift;
495	–	segmentMask = ssize - 1;
496	–	this.segments = new Segment[ssize];
3634
3635	<	if (initialCapacity > MAXIMUM_CAPACITY)
499	<	initialCapacity = MAXIMUM_CAPACITY;
500	<	int c = initialCapacity / ssize;
501	<	if (c * ssize < initialCapacity)
502	<	++c;
503	<	int cap = 1;
504	<	while (cap < c)
505	<	cap <<= 1;
3635	>	public long estimateSize() { return est; }
3636
3637	<	for (int i = 0; i < this.segments.length; ++i)
3638	<	this.segments[i] = new Segment<K,V>(cap, loadFactor);
3637	>	public int characteristics() {
3638	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3639	>	Spliterator.NONNULL;
3640	>	}
3641		}
3642
3643	+	// Parallel bulk operations
3644	+
3645		/**
3646	<	* Constructs a new, empty map with the specified initial
3647	<	* capacity,  and with default load factor and segments.
3646	>	* Computes initial batch value for bulk tasks. The returned value
3647	>	* is approximately exp2 of the number of times (minus one) to
3648	>	* split task by two before executing leaf action. This value is
3649	>	* faster to compute and more convenient to use as a guide to
3650	>	* splitting than is the depth, since it is used while dividing by
3651	>	* two anyway.
3652	>	*/
3653	>	final int batchFor(long b) {
3654	>	long n;
3655	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3656	>	return 0;
3657	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3658	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3659	>	}
3660	>
3661	>	/**
3662	>	* Performs the given action for each (key, value).
3663		*
3664	<	* @param initialCapacity the initial capacity of the
3665	<	* ConcurrentHashMap.
3666	<	* @throws IllegalArgumentException if the initial capacity of
3667	<	* elements is negative.
3664	>	* @param parallelismThreshold the (estimated) number of elements
3665	>	* needed for this operation to be executed in parallel
3666	>	* @param action the action
3667	>	* @since 1.8
3668		*/
3669	<	public ConcurrentHashMap(int initialCapacity) {
3670	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3669	>	public void forEach(long parallelismThreshold,
3670	>	BiConsumer<? super K,? super V> action) {
3671	>	if (action == null) throw new NullPointerException();
3672	>	new ForEachMappingTask<K,V>
3673	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3674	>	action).invoke();
3675		}
3676
3677		/**
3678	<	* Constructs a new, empty map with a default initial capacity,
3679	<	* load factor, and number of segments.
3678	>	* Performs the given action for each non-null transformation
3679	>	* of each (key, value).
3680	>	*
3681	>	* @param parallelismThreshold the (estimated) number of elements
3682	>	* needed for this operation to be executed in parallel
3683	>	* @param transformer a function returning the transformation
3684	>	* for an element, or null if there is no transformation (in
3685	>	* which case the action is not applied)
3686	>	* @param action the action
3687	>	* @param <U> the return type of the transformer
3688	>	* @since 1.8
3689		*/
3690	<	public ConcurrentHashMap() {
3691	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3690	>	public <U> void forEach(long parallelismThreshold,
3691	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3692	>	Consumer<? super U> action) {
3693	>	if (transformer == null || action == null)
3694	>	throw new NullPointerException();
3695	>	new ForEachTransformedMappingTask<K,V,U>
3696	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3697	>	transformer, action).invoke();
3698		}
3699
3700		/**
3701	<	* Constructs a new map with the same mappings as the given map.  The
3702	<	* map is created with a capacity of twice the number of mappings in
3703	<	* the given map or 11 (whichever is greater), and a default load factor.
3701	>	* Returns a non-null result from applying the given search
3702	>	* function on each (key, value), or null if none.  Upon
3703	>	* success, further element processing is suppressed and the
3704	>	* results of any other parallel invocations of the search
3705	>	* function are ignored.
3706	>	*
3707	>	* @param parallelismThreshold the (estimated) number of elements
3708	>	* needed for this operation to be executed in parallel
3709	>	* @param searchFunction a function returning a non-null
3710	>	* result on success, else null
3711	>	* @param <U> the return type of the search function
3712	>	* @return a non-null result from applying the given search
3713	>	* function on each (key, value), or null if none
3714	>	* @since 1.8
3715		*/
3716	<	public <A extends K, B extends V> ConcurrentHashMap(Map<A,B> t) {
3717	<	this(Math.max((int) (t.size() / DEFAULT_LOAD_FACTOR) + 1,
3718	<	11),
3719	<	DEFAULT_LOAD_FACTOR, DEFAULT_SEGMENTS);
3720	<	putAll(t);
3716	>	public <U> U search(long parallelismThreshold,
3717	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3718	>	if (searchFunction == null) throw new NullPointerException();
3719	>	return new SearchMappingsTask<K,V,U>
3720	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3721	>	searchFunction, new AtomicReference<U>()).invoke();
3722		}
3723
3724	<	// inherit Map javadoc
3725	<	public int size() {
3726	<	int c = 0;
3727	<	for (int i = 0; i < segments.length; ++i)
3728	<	c += segments[i].count;
3729	<	return c;
3724	>	/**
3725	>	* Returns the result of accumulating the given transformation
3726	>	* of all (key, value) pairs using the given reducer to
3727	>	* combine values, or null if none.
3728	>	*
3729	>	* @param parallelismThreshold the (estimated) number of elements
3730	>	* needed for this operation to be executed in parallel
3731	>	* @param transformer a function returning the transformation
3732	>	* for an element, or null if there is no transformation (in
3733	>	* which case it is not combined)
3734	>	* @param reducer a commutative associative combining function
3735	>	* @param <U> the return type of the transformer
3736	>	* @return the result of accumulating the given transformation
3737	>	* of all (key, value) pairs
3738	>	* @since 1.8
3739	>	*/
3740	>	public <U> U reduce(long parallelismThreshold,
3741	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3742	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3743	>	if (transformer == null || reducer == null)
3744	>	throw new NullPointerException();
3745	>	return new MapReduceMappingsTask<K,V,U>
3746	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3747	>	null, transformer, reducer).invoke();
3748		}
3749
3750	<	// inherit Map javadoc
3751	<	public boolean isEmpty() {
3752	<	for (int i = 0; i < segments.length; ++i)
3753	<	if (segments[i].count != 0)
3754	<	return false;
3755	<	return true;
3750	>	/**
3751	>	* Returns the result of accumulating the given transformation
3752	>	* of all (key, value) pairs using the given reducer to
3753	>	* combine values, and the given basis as an identity value.
3754	>	*
3755	>	* @param parallelismThreshold the (estimated) number of elements
3756	>	* needed for this operation to be executed in parallel
3757	>	* @param transformer a function returning the transformation
3758	>	* for an element
3759	>	* @param basis the identity (initial default value) for the reduction
3760	>	* @param reducer a commutative associative combining function
3761	>	* @return the result of accumulating the given transformation
3762	>	* of all (key, value) pairs
3763	>	* @since 1.8
3764	>	*/
3765	>	public double reduceToDouble(long parallelismThreshold,
3766	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3767	>	double basis,
3768	>	DoubleBinaryOperator reducer) {
3769	>	if (transformer == null || reducer == null)
3770	>	throw new NullPointerException();
3771	>	return new MapReduceMappingsToDoubleTask<K,V>
3772	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3773	>	null, transformer, basis, reducer).invoke();
3774		}
3775
3776		/**
3777	<	* Returns the value to which the specified key is mapped in this table.
3777	>	* Returns the result of accumulating the given transformation
3778	>	* of all (key, value) pairs using the given reducer to
3779	>	* combine values, and the given basis as an identity value.
3780		*
3781	<	* @param   key   a key in the table.
3782	<	* @return  the value to which the key is mapped in this table;
3783	<	*          <code>null</code> if the key is not mapped to any value in
3784	<	*          this table.
3785	<	* @throws  NullPointerException  if the key is
3786	<	*               <code>null</code>.
3787	<	* @see     #put(Object, Object)
3781	>	* @param parallelismThreshold the (estimated) number of elements
3782	>	* needed for this operation to be executed in parallel
3783	>	* @param transformer a function returning the transformation
3784	>	* for an element
3785	>	* @param basis the identity (initial default value) for the reduction
3786	>	* @param reducer a commutative associative combining function
3787	>	* @return the result of accumulating the given transformation
3788	>	* of all (key, value) pairs
3789	>	* @since 1.8
3790		*/
3791	<	public V get(Object key) {
3792	<	int hash = hash(key); // throws NullPointerException if key null
3793	<	return segmentFor(hash).get((K) key, hash);
3791	>	public long reduceToLong(long parallelismThreshold,
3792	>	ToLongBiFunction<? super K, ? super V> transformer,
3793	>	long basis,
3794	>	LongBinaryOperator reducer) {
3795	>	if (transformer == null || reducer == null)
3796	>	throw new NullPointerException();
3797	>	return new MapReduceMappingsToLongTask<K,V>
3798	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3799	>	null, transformer, basis, reducer).invoke();
3800		}
3801
3802		/**
3803	<	* Tests if the specified object is a key in this table.
3803	>	* Returns the result of accumulating the given transformation
3804	>	* of all (key, value) pairs using the given reducer to
3805	>	* combine values, and the given basis as an identity value.
3806		*
3807	<	* @param   key   possible key.
3808	<	* @return  <code>true</code> if and only if the specified object
3809	<	*          is a key in this table, as determined by the
3810	<	*          <tt>equals</tt> method; <code>false</code> otherwise.
3811	<	* @throws  NullPointerException  if the key is
3812	<	*               <code>null</code>.
3813	<	* @see     #contains(Object)
3807	>	* @param parallelismThreshold the (estimated) number of elements
3808	>	* needed for this operation to be executed in parallel
3809	>	* @param transformer a function returning the transformation
3810	>	* for an element
3811	>	* @param basis the identity (initial default value) for the reduction
3812	>	* @param reducer a commutative associative combining function
3813	>	* @return the result of accumulating the given transformation
3814	>	* of all (key, value) pairs
3815	>	* @since 1.8
3816		*/
3817	<	public boolean containsKey(Object key) {
3818	<	int hash = hash(key); // throws NullPointerException if key null
3819	<	return segmentFor(hash).containsKey(key, hash);
3817	>	public int reduceToInt(long parallelismThreshold,
3818	>	ToIntBiFunction<? super K, ? super V> transformer,
3819	>	int basis,
3820	>	IntBinaryOperator reducer) {
3821	>	if (transformer == null || reducer == null)
3822	>	throw new NullPointerException();
3823	>	return new MapReduceMappingsToIntTask<K,V>
3824	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3825	>	null, transformer, basis, reducer).invoke();
3826		}
3827
3828		/**
3829	<	* Returns <tt>true</tt> if this map maps one or more keys to the
594	<	* specified value. Note: This method requires a full internal
595	<	* traversal of the hash table, and so is much slower than
596	<	* method <tt>containsKey</tt>.
3829	>	* Performs the given action for each key.
3830		*
3831	<	* @param value value whose presence in this map is to be tested.
3832	<	* @return <tt>true</tt> if this map maps one or more keys to the
3833	<	* specified value.
3834	<	* @throws  NullPointerException  if the value is <code>null</code>.
3831	>	* @param parallelismThreshold the (estimated) number of elements
3832	>	* needed for this operation to be executed in parallel
3833	>	* @param action the action
3834	>	* @since 1.8
3835		*/
3836	<	public boolean containsValue(Object value) {
3837	<	if (value == null)
3836	>	public void forEachKey(long parallelismThreshold,
3837	>	Consumer<? super K> action) {
3838	>	if (action == null) throw new NullPointerException();
3839	>	new ForEachKeyTask<K,V>
3840	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3841	>	action).invoke();
3842	>	}
3843	>
3844	>	/**
3845	>	* Performs the given action for each non-null transformation
3846	>	* of each key.
3847	>	*
3848	>	* @param parallelismThreshold the (estimated) number of elements
3849	>	* needed for this operation to be executed in parallel
3850	>	* @param transformer a function returning the transformation
3851	>	* for an element, or null if there is no transformation (in
3852	>	* which case the action is not applied)
3853	>	* @param action the action
3854	>	* @param <U> the return type of the transformer
3855	>	* @since 1.8
3856	>	*/
3857	>	public <U> void forEachKey(long parallelismThreshold,
3858	>	Function<? super K, ? extends U> transformer,
3859	>	Consumer<? super U> action) {
3860	>	if (transformer == null || action == null)
3861		throw new NullPointerException();
3862	+	new ForEachTransformedKeyTask<K,V,U>
3863	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3864	+	transformer, action).invoke();
3865	+	}
3866
3867	<	for (int i = 0; i < segments.length; ++i) {
3868	<	if (segments[i].containsValue(value))
3869	<	return true;
3870	<	}
3871	<	return false;
3867	>	/**
3868	>	* Returns a non-null result from applying the given search
3869	>	* function on each key, or null if none. Upon success,
3870	>	* further element processing is suppressed and the results of
3871	>	* any other parallel invocations of the search function are
3872	>	* ignored.
3873	>	*
3874	>	* @param parallelismThreshold the (estimated) number of elements
3875	>	* needed for this operation to be executed in parallel
3876	>	* @param searchFunction a function returning a non-null
3877	>	* result on success, else null
3878	>	* @param <U> the return type of the search function
3879	>	* @return a non-null result from applying the given search
3880	>	* function on each key, or null if none
3881	>	* @since 1.8
3882	>	*/
3883	>	public <U> U searchKeys(long parallelismThreshold,
3884	>	Function<? super K, ? extends U> searchFunction) {
3885	>	if (searchFunction == null) throw new NullPointerException();
3886	>	return new SearchKeysTask<K,V,U>
3887	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3888	>	searchFunction, new AtomicReference<U>()).invoke();
3889		}
3890	+
3891		/**
3892	<	* Tests if some key maps into the specified value in this table.
3893	<	* This operation is more expensive than the <code>containsKey</code>
616	<	* method.<p>
3892	>	* Returns the result of accumulating all keys using the given
3893	>	* reducer to combine values, or null if none.
3894		*
3895	<	* Note that this method is identical in functionality to containsValue,
3896	<	* (which is part of the Map interface in the collections framework).
3895	>	* @param parallelismThreshold the (estimated) number of elements
3896	>	* needed for this operation to be executed in parallel
3897	>	* @param reducer a commutative associative combining function
3898	>	* @return the result of accumulating all keys using the given
3899	>	* reducer to combine values, or null if none
3900	>	* @since 1.8
3901	>	*/
3902	>	public K reduceKeys(long parallelismThreshold,
3903	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3904	>	if (reducer == null) throw new NullPointerException();
3905	>	return new ReduceKeysTask<K,V>
3906	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3907	>	null, reducer).invoke();
3908	>	}
3909	>
3910	>	/**
3911	>	* Returns the result of accumulating the given transformation
3912	>	* of all keys using the given reducer to combine values, or
3913	>	* null if none.
3914		*
3915	<	* @param      value   a value to search for.
3916	<	* @return     <code>true</code> if and only if some key maps to the
3917	<	*             <code>value</code> argument in this table as
3918	<	*             determined by the <tt>equals</tt> method;
3919	<	*             <code>false</code> otherwise.
3920	<	* @throws  NullPointerException  if the value is <code>null</code>.
3921	<	* @see        #containsKey(Object)
3922	<	* @see        #containsValue(Object)
3923	<	* @see   Map
3915	>	* @param parallelismThreshold the (estimated) number of elements
3916	>	* needed for this operation to be executed in parallel
3917	>	* @param transformer a function returning the transformation
3918	>	* for an element, or null if there is no transformation (in
3919	>	* which case it is not combined)
3920	>	* @param reducer a commutative associative combining function
3921	>	* @param <U> the return type of the transformer
3922	>	* @return the result of accumulating the given transformation
3923	>	* of all keys
3924	>	* @since 1.8
3925		*/
3926	<	public boolean contains(Object value) {
3927	<	return containsValue(value);
3926	>	public <U> U reduceKeys(long parallelismThreshold,
3927	>	Function<? super K, ? extends U> transformer,
3928	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3929	>	if (transformer == null || reducer == null)
3930	>	throw new NullPointerException();
3931	>	return new MapReduceKeysTask<K,V,U>
3932	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3933	>	null, transformer, reducer).invoke();
3934		}
3935
3936		/**
3937	<	* Maps the specified <code>key</code> to the specified
3938	<	* <code>value</code> in this table. Neither the key nor the
3939	<	* value can be <code>null</code>. <p>
3937	>	* Returns the result of accumulating the given transformation
3938	>	* of all keys using the given reducer to combine values, and
3939	>	* the given basis as an identity value.
3940		*
3941	<	* The value can be retrieved by calling the <code>get</code> method
3942	<	* with a key that is equal to the original key.
3941	>	* @param parallelismThreshold the (estimated) number of elements
3942	>	* needed for this operation to be executed in parallel
3943	>	* @param transformer a function returning the transformation
3944	>	* for an element
3945	>	* @param basis the identity (initial default value) for the reduction
3946	>	* @param reducer a commutative associative combining function
3947	>	* @return the result of accumulating the given transformation
3948	>	* of all keys
3949	>	* @since 1.8
3950	>	*/
3951	>	public double reduceKeysToDouble(long parallelismThreshold,
3952	>	ToDoubleFunction<? super K> transformer,
3953	>	double basis,
3954	>	DoubleBinaryOperator reducer) {
3955	>	if (transformer == null || reducer == null)
3956	>	throw new NullPointerException();
3957	>	return new MapReduceKeysToDoubleTask<K,V>
3958	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3959	>	null, transformer, basis, reducer).invoke();
3960	>	}
3961	>
3962	>	/**
3963	>	* Returns the result of accumulating the given transformation
3964	>	* of all keys using the given reducer to combine values, and
3965	>	* the given basis as an identity value.
3966		*
3967	<	* @param      key     the table key.
3968	<	* @param      value   the value.
3969	<	* @return     the previous value of the specified key in this table,
3970	<	*             or <code>null</code> if it did not have one.
3971	<	* @throws  NullPointerException  if the key or value is
3972	<	*               <code>null</code>.
3973	<	* @see     Object#equals(Object)
3974	<	* @see     #get(Object)
3967	>	* @param parallelismThreshold the (estimated) number of elements
3968	>	* needed for this operation to be executed in parallel
3969	>	* @param transformer a function returning the transformation
3970	>	* for an element
3971	>	* @param basis the identity (initial default value) for the reduction
3972	>	* @param reducer a commutative associative combining function
3973	>	* @return the result of accumulating the given transformation
3974	>	* of all keys
3975	>	* @since 1.8
3976		*/
3977	<	public V put(K key, V value) {
3978	<	if (value == null)
3977	>	public long reduceKeysToLong(long parallelismThreshold,
3978	>	ToLongFunction<? super K> transformer,
3979	>	long basis,
3980	>	LongBinaryOperator reducer) {
3981	>	if (transformer == null || reducer == null)
3982		throw new NullPointerException();
3983	<	int hash = hash(key);
3984	<	return segmentFor(hash).put(key, hash, value, false);
3983	>	return new MapReduceKeysToLongTask<K,V>
3984	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3985	>	null, transformer, basis, reducer).invoke();
3986		}
3987
3988		/**
3989	<	* If the specified key is not already associated
3990	<	* with a value, associate it with the given value.
3991	<	* This is equivalent to
663	<	* <pre>
664	<	*   if (!map.containsKey(key)) map.put(key, value);
665	<	*   return get(key);
666	<	* </pre>
667	<	* Except that the action is performed atomically.
668	<	* @param key key with which the specified value is to be associated.
669	<	* @param value value to be associated with the specified key.
670	<	* @return previous value associated with specified key, or <tt>null</tt>
671	<	*         if there was no mapping for key.  A <tt>null</tt> return can
672	<	*         also indicate that the map previously associated <tt>null</tt>
673	<	*         with the specified key, if the implementation supports
674	<	*         <tt>null</tt> values.
675	<	*
676	<	* @throws NullPointerException this map does not permit <tt>null</tt>
677	<	*            keys or values, and the specified key or value is
678	<	*            <tt>null</tt>.
3989	>	* Returns the result of accumulating the given transformation
3990	>	* of all keys using the given reducer to combine values, and
3991	>	* the given basis as an identity value.
3992		*
3993	<	**/
3994	<	public V putIfAbsent(K key, V value) {
3995	<	if (value == null)
3993	>	* @param parallelismThreshold the (estimated) number of elements
3994	>	* needed for this operation to be executed in parallel
3995	>	* @param transformer a function returning the transformation
3996	>	* for an element
3997	>	* @param basis the identity (initial default value) for the reduction
3998	>	* @param reducer a commutative associative combining function
3999	>	* @return the result of accumulating the given transformation
4000	>	* of all keys
4001	>	* @since 1.8
4002	>	*/
4003	>	public int reduceKeysToInt(long parallelismThreshold,
4004	>	ToIntFunction<? super K> transformer,
4005	>	int basis,
4006	>	IntBinaryOperator reducer) {
4007	>	if (transformer == null || reducer == null)
4008		throw new NullPointerException();
4009	<	int hash = hash(key);
4010	<	return segmentFor(hash).put(key, hash, value, true);
4009	>	return new MapReduceKeysToIntTask<K,V>
4010	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4011	>	null, transformer, basis, reducer).invoke();
4012		}
4013
4014	+	/**
4015	+	* Performs the given action for each value.
4016	+	*
4017	+	* @param parallelismThreshold the (estimated) number of elements
4018	+	* needed for this operation to be executed in parallel
4019	+	* @param action the action
4020	+	* @since 1.8
4021	+	*/
4022	+	public void forEachValue(long parallelismThreshold,
4023	+	Consumer<? super V> action) {
4024	+	if (action == null)
4025	+	throw new NullPointerException();
4026	+	new ForEachValueTask<K,V>
4027	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4028	+	action).invoke();
4029	+	}
4030
4031		/**
4032	<	* Copies all of the mappings from the specified map to this one.
4032	>	* Performs the given action for each non-null transformation
4033	>	* of each value.
4034		*
4035	<	* These mappings replace any mappings that this map had for any of the
4036	<	* keys currently in the specified Map.
4035	>	* @param parallelismThreshold the (estimated) number of elements
4036	>	* needed for this operation to be executed in parallel
4037	>	* @param transformer a function returning the transformation
4038	>	* for an element, or null if there is no transformation (in
4039	>	* which case the action is not applied)
4040	>	* @param action the action
4041	>	* @param <U> the return type of the transformer
4042	>	* @since 1.8
4043	>	*/
4044	>	public <U> void forEachValue(long parallelismThreshold,
4045	>	Function<? super V, ? extends U> transformer,
4046	>	Consumer<? super U> action) {
4047	>	if (transformer == null || action == null)
4048	>	throw new NullPointerException();
4049	>	new ForEachTransformedValueTask<K,V,U>
4050	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4051	>	transformer, action).invoke();
4052	>	}
4053	>
4054	>	/**
4055	>	* Returns a non-null result from applying the given search
4056	>	* function on each value, or null if none.  Upon success,
4057	>	* further element processing is suppressed and the results of
4058	>	* any other parallel invocations of the search function are
4059	>	* ignored.
4060		*
4061	<	* @param t Mappings to be stored in this map.
4061	>	* @param parallelismThreshold the (estimated) number of elements
4062	>	* needed for this operation to be executed in parallel
4063	>	* @param searchFunction a function returning a non-null
4064	>	* result on success, else null
4065	>	* @param <U> the return type of the search function
4066	>	* @return a non-null result from applying the given search
4067	>	* function on each value, or null if none
4068	>	* @since 1.8
4069		*/
4070	<	public void putAll(Map<? extends K, ? extends V> t) {
4071	<	Iterator<Map.Entry<? extends K, ? extends V>> it = t.entrySet().iterator();
4072	<	while (it.hasNext()) {
4073	<	Entry<? extends K, ? extends V> e = it.next();
4074	<	put(e.getKey(), e.getValue());
4075	<	}
4070	>	public <U> U searchValues(long parallelismThreshold,
4071	>	Function<? super V, ? extends U> searchFunction) {
4072	>	if (searchFunction == null) throw new NullPointerException();
4073	>	return new SearchValuesTask<K,V,U>
4074	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4075	>	searchFunction, new AtomicReference<U>()).invoke();
4076		}
4077
4078		/**
4079	<	* Removes the key (and its corresponding value) from this
4080	<	* table. This method does nothing if the key is not in the table.
4079	>	* Returns the result of accumulating all values using the
4080	>	* given reducer to combine values, or null if none.
4081		*
4082	<	* @param   key   the key that needs to be removed.
4083	<	* @return  the value to which the key had been mapped in this table,
4084	<	*          or <code>null</code> if the key did not have a mapping.
4085	<	* @throws  NullPointerException  if the key is
4086	<	*               <code>null</code>.
4082	>	* @param parallelismThreshold the (estimated) number of elements
4083	>	* needed for this operation to be executed in parallel
4084	>	* @param reducer a commutative associative combining function
4085	>	* @return the result of accumulating all values
4086	>	* @since 1.8
4087		*/
4088	<	public V remove(Object key) {
4089	<	int hash = hash(key);
4090	<	return segmentFor(hash).remove(key, hash, null);
4088	>	public V reduceValues(long parallelismThreshold,
4089	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4090	>	if (reducer == null) throw new NullPointerException();
4091	>	return new ReduceValuesTask<K,V>
4092	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4093	>	null, reducer).invoke();
4094		}
4095
4096		/**
4097	<	* Removes the (key, value) pair from this
4098	<	* table. This method does nothing if the key is not in the table,
4099	<	* or if the key is associated with a different value.
4100	<	*
4101	<	* @param   key   the key that needs to be removed.
4102	<	* @param   value   the associated value. If the value is null,
4103	<	*                   it means "any value".
4104	<	* @return  the value to which the key had been mapped in this table,
4105	<	*          or <code>null</code> if the key did not have a mapping.
4106	<	* @throws  NullPointerException  if the key is
4107	<	*               <code>null</code>.
4097	>	* Returns the result of accumulating the given transformation
4098	>	* of all values using the given reducer to combine values, or
4099	>	* null if none.
4100	>	*
4101	>	* @param parallelismThreshold the (estimated) number of elements
4102	>	* needed for this operation to be executed in parallel
4103	>	* @param transformer a function returning the transformation
4104	>	* for an element, or null if there is no transformation (in
4105	>	* which case it is not combined)
4106	>	* @param reducer a commutative associative combining function
4107	>	* @param <U> the return type of the transformer
4108	>	* @return the result of accumulating the given transformation
4109	>	* of all values
4110	>	* @since 1.8
4111		*/
4112	<	public boolean remove(Object key, Object value) {
4113	<	int hash = hash(key);
4114	<	return segmentFor(hash).remove(key, hash, value) != null;
4112	>	public <U> U reduceValues(long parallelismThreshold,
4113	>	Function<? super V, ? extends U> transformer,
4114	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4115	>	if (transformer == null || reducer == null)
4116	>	throw new NullPointerException();
4117	>	return new MapReduceValuesTask<K,V,U>
4118	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4119	>	null, transformer, reducer).invoke();
4120		}
4121
4122		/**
4123	<	* Removes all mappings from this map.
4123	>	* Returns the result of accumulating the given transformation
4124	>	* of all values using the given reducer to combine values,
4125	>	* and the given basis as an identity value.
4126	>	*
4127	>	* @param parallelismThreshold the (estimated) number of elements
4128	>	* needed for this operation to be executed in parallel
4129	>	* @param transformer a function returning the transformation
4130	>	* for an element
4131	>	* @param basis the identity (initial default value) for the reduction
4132	>	* @param reducer a commutative associative combining function
4133	>	* @return the result of accumulating the given transformation
4134	>	* of all values
4135	>	* @since 1.8
4136		*/
4137	<	public void clear() {
4138	<	for (int i = 0; i < segments.length; ++i)
4139	<	segments[i].clear();
4137	>	public double reduceValuesToDouble(long parallelismThreshold,
4138	>	ToDoubleFunction<? super V> transformer,
4139	>	double basis,
4140	>	DoubleBinaryOperator reducer) {
4141	>	if (transformer == null || reducer == null)
4142	>	throw new NullPointerException();
4143	>	return new MapReduceValuesToDoubleTask<K,V>
4144	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4145	>	null, transformer, basis, reducer).invoke();
4146		}
4147
4148	+	/**
4149	+	* Returns the result of accumulating the given transformation
4150	+	* of all values using the given reducer to combine values,
4151	+	* and the given basis as an identity value.
4152	+	*
4153	+	* @param parallelismThreshold the (estimated) number of elements
4154	+	* needed for this operation to be executed in parallel
4155	+	* @param transformer a function returning the transformation
4156	+	* for an element
4157	+	* @param basis the identity (initial default value) for the reduction
4158	+	* @param reducer a commutative associative combining function
4159	+	* @return the result of accumulating the given transformation
4160	+	* of all values
4161	+	* @since 1.8
4162	+	*/
4163	+	public long reduceValuesToLong(long parallelismThreshold,
4164	+	ToLongFunction<? super V> transformer,
4165	+	long basis,
4166	+	LongBinaryOperator reducer) {
4167	+	if (transformer == null || reducer == null)
4168	+	throw new NullPointerException();
4169	+	return new MapReduceValuesToLongTask<K,V>
4170	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4171	+	null, transformer, basis, reducer).invoke();
4172	+	}
4173
4174		/**
4175	<	* Returns a shallow copy of this
4176	<	* <tt>ConcurrentHashMap</tt> instance: the keys and
4177	<	* values themselves are not cloned.
4175	>	* Returns the result of accumulating the given transformation
4176	>	* of all values using the given reducer to combine values,
4177	>	* and the given basis as an identity value.
4178		*
4179	<	* @return a shallow copy of this map.
4179	>	* @param parallelismThreshold the (estimated) number of elements
4180	>	* needed for this operation to be executed in parallel
4181	>	* @param transformer a function returning the transformation
4182	>	* for an element
4183	>	* @param basis the identity (initial default value) for the reduction
4184	>	* @param reducer a commutative associative combining function
4185	>	* @return the result of accumulating the given transformation
4186	>	* of all values
4187	>	* @since 1.8
4188		*/
4189	<	public Object clone() {
4190	<	// We cannot call super.clone, since it would share final
4191	<	// segments array, and there's no way to reassign finals.
4189	>	public int reduceValuesToInt(long parallelismThreshold,
4190	>	ToIntFunction<? super V> transformer,
4191	>	int basis,
4192	>	IntBinaryOperator reducer) {
4193	>	if (transformer == null || reducer == null)
4194	>	throw new NullPointerException();
4195	>	return new MapReduceValuesToIntTask<K,V>
4196	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4197	>	null, transformer, basis, reducer).invoke();
4198	>	}
4199
4200	<	float lf = segments[0].loadFactor;
4201	<	int segs = segments.length;
4202	<	int cap = (int)(size() / lf);
4203	<	if (cap < segs) cap = segs;
4204	<	ConcurrentHashMap<K,V> t = new ConcurrentHashMap<K,V>(cap, lf, segs);
4205	<	t.putAll(this);
4206	<	return t;
4200	>	/**
4201	>	* Performs the given action for each entry.
4202	>	*
4203	>	* @param parallelismThreshold the (estimated) number of elements
4204	>	* needed for this operation to be executed in parallel
4205	>	* @param action the action
4206	>	* @since 1.8
4207	>	*/
4208	>	public void forEachEntry(long parallelismThreshold,
4209	>	Consumer<? super Map.Entry<K,V>> action) {
4210	>	if (action == null) throw new NullPointerException();
4211	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4212	>	action).invoke();
4213		}
4214
4215		/**
4216	<	* Returns a set view of the keys contained in this map.  The set is
4217	<	* backed by the map, so changes to the map are reflected in the set, and
770	<	* vice-versa.  The set supports element removal, which removes the
771	<	* corresponding mapping from this map, via the <tt>Iterator.remove</tt>,
772	<	* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and
773	<	* <tt>clear</tt> operations.  It does not support the <tt>add</tt> or
774	<	* <tt>addAll</tt> operations.
775	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
776	<	* will never throw {@link java.util.ConcurrentModificationException},
777	<	* and guarantees to traverse elements as they existed upon
778	<	* construction of the iterator, and may (but is not guaranteed to)
779	<	* reflect any modifications subsequent to construction.
4216	>	* Performs the given action for each non-null transformation
4217	>	* of each entry.
4218		*
4219	<	* @return a set view of the keys contained in this map.
4219	>	* @param parallelismThreshold the (estimated) number of elements
4220	>	* needed for this operation to be executed in parallel
4221	>	* @param transformer a function returning the transformation
4222	>	* for an element, or null if there is no transformation (in
4223	>	* which case the action is not applied)
4224	>	* @param action the action
4225	>	* @param <U> the return type of the transformer
4226	>	* @since 1.8
4227		*/
4228	<	public Set<K> keySet() {
4229	<	Set<K> ks = keySet;
4230	<	return (ks != null) ? ks : (keySet = new KeySet());
4228	>	public <U> void forEachEntry(long parallelismThreshold,
4229	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4230	>	Consumer<? super U> action) {
4231	>	if (transformer == null || action == null)
4232	>	throw new NullPointerException();
4233	>	new ForEachTransformedEntryTask<K,V,U>
4234	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4235	>	transformer, action).invoke();
4236		}
4237
4238	+	/**
4239	+	* Returns a non-null result from applying the given search
4240	+	* function on each entry, or null if none.  Upon success,
4241	+	* further element processing is suppressed and the results of
4242	+	* any other parallel invocations of the search function are
4243	+	* ignored.
4244	+	*
4245	+	* @param parallelismThreshold the (estimated) number of elements
4246	+	* needed for this operation to be executed in parallel
4247	+	* @param searchFunction a function returning a non-null
4248	+	* result on success, else null
4249	+	* @param <U> the return type of the search function
4250	+	* @return a non-null result from applying the given search
4251	+	* function on each entry, or null if none
4252	+	* @since 1.8
4253	+	*/
4254	+	public <U> U searchEntries(long parallelismThreshold,
4255	+	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4256	+	if (searchFunction == null) throw new NullPointerException();
4257	+	return new SearchEntriesTask<K,V,U>
4258	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4259	+	searchFunction, new AtomicReference<U>()).invoke();
4260	+	}
4261
4262		/**
4263	<	* Returns a collection view of the values contained in this map.  The
4264	<	* collection is backed by the map, so changes to the map are reflected in
792	<	* the collection, and vice-versa.  The collection supports element
793	<	* removal, which removes the corresponding mapping from this map, via the
794	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
795	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
796	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
797	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
798	<	* will never throw {@link java.util.ConcurrentModificationException},
799	<	* and guarantees to traverse elements as they existed upon
800	<	* construction of the iterator, and may (but is not guaranteed to)
801	<	* reflect any modifications subsequent to construction.
4263	>	* Returns the result of accumulating all entries using the
4264	>	* given reducer to combine values, or null if none.
4265		*
4266	<	* @return a collection view of the values contained in this map.
4266	>	* @param parallelismThreshold the (estimated) number of elements
4267	>	* needed for this operation to be executed in parallel
4268	>	* @param reducer a commutative associative combining function
4269	>	* @return the result of accumulating all entries
4270	>	* @since 1.8
4271		*/
4272	<	public Collection<V> values() {
4273	<	Collection<V> vs = values;
4274	<	return (vs != null) ? vs : (values = new Values());
4272	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4273	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4274	>	if (reducer == null) throw new NullPointerException();
4275	>	return new ReduceEntriesTask<K,V>
4276	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4277	>	null, reducer).invoke();
4278		}
4279
4280	+	/**
4281	+	* Returns the result of accumulating the given transformation
4282	+	* of all entries using the given reducer to combine values,
4283	+	* or null if none.
4284	+	*
4285	+	* @param parallelismThreshold the (estimated) number of elements
4286	+	* needed for this operation to be executed in parallel
4287	+	* @param transformer a function returning the transformation
4288	+	* for an element, or null if there is no transformation (in
4289	+	* which case it is not combined)
4290	+	* @param reducer a commutative associative combining function
4291	+	* @param <U> the return type of the transformer
4292	+	* @return the result of accumulating the given transformation
4293	+	* of all entries
4294	+	* @since 1.8
4295	+	*/
4296	+	public <U> U reduceEntries(long parallelismThreshold,
4297	+	Function<Map.Entry<K,V>, ? extends U> transformer,
4298	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
4299	+	if (transformer == null || reducer == null)
4300	+	throw new NullPointerException();
4301	+	return new MapReduceEntriesTask<K,V,U>
4302	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4303	+	null, transformer, reducer).invoke();
4304	+	}
4305
4306		/**
4307	<	* Returns a collection view of the mappings contained in this map.  Each
4308	<	* element in the returned collection is a <tt>Map.Entry</tt>.  The
4309	<	* collection is backed by the map, so changes to the map are reflected in
815	<	* the collection, and vice-versa.  The collection supports element
816	<	* removal, which removes the corresponding mapping from the map, via the
817	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
818	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> operations.
819	<	* It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
820	<	* The returned <tt>iterator</tt> is a "weakly consistent" iterator that
821	<	* will never throw {@link java.util.ConcurrentModificationException},
822	<	* and guarantees to traverse elements as they existed upon
823	<	* construction of the iterator, and may (but is not guaranteed to)
824	<	* reflect any modifications subsequent to construction.
4307	>	* Returns the result of accumulating the given transformation
4308	>	* of all entries using the given reducer to combine values,
4309	>	* and the given basis as an identity value.
4310		*
4311	<	* @return a collection view of the mappings contained in this map.
4311	>	* @param parallelismThreshold the (estimated) number of elements
4312	>	* needed for this operation to be executed in parallel
4313	>	* @param transformer a function returning the transformation
4314	>	* for an element
4315	>	* @param basis the identity (initial default value) for the reduction
4316	>	* @param reducer a commutative associative combining function
4317	>	* @return the result of accumulating the given transformation
4318	>	* of all entries
4319	>	* @since 1.8
4320		*/
4321	<	public Set<Map.Entry<K,V>> entrySet() {
4322	<	Set<Map.Entry<K,V>> es = entrySet;
4323	<	return (es != null) ? es : (entrySet = new EntrySet());
4321	>	public double reduceEntriesToDouble(long parallelismThreshold,
4322	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4323	>	double basis,
4324	>	DoubleBinaryOperator reducer) {
4325	>	if (transformer == null || reducer == null)
4326	>	throw new NullPointerException();
4327	>	return new MapReduceEntriesToDoubleTask<K,V>
4328	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4329	>	null, transformer, basis, reducer).invoke();
4330		}
4331
4332	+	/**
4333	+	* Returns the result of accumulating the given transformation
4334	+	* of all entries using the given reducer to combine values,
4335	+	* and the given basis as an identity value.
4336	+	*
4337	+	* @param parallelismThreshold the (estimated) number of elements
4338	+	* needed for this operation to be executed in parallel
4339	+	* @param transformer a function returning the transformation
4340	+	* for an element
4341	+	* @param basis the identity (initial default value) for the reduction
4342	+	* @param reducer a commutative associative combining function
4343	+	* @return the result of accumulating the given transformation
4344	+	* of all entries
4345	+	* @since 1.8
4346	+	*/
4347	+	public long reduceEntriesToLong(long parallelismThreshold,
4348	+	ToLongFunction<Map.Entry<K,V>> transformer,
4349	+	long basis,
4350	+	LongBinaryOperator reducer) {
4351	+	if (transformer == null || reducer == null)
4352	+	throw new NullPointerException();
4353	+	return new MapReduceEntriesToLongTask<K,V>
4354	+	(null, batchFor(parallelismThreshold), 0, 0, table,
4355	+	null, transformer, basis, reducer).invoke();
4356	+	}
4357
4358		/**
4359	<	* Returns an enumeration of the keys in this table.
4359	>	* Returns the result of accumulating the given transformation
4360	>	* of all entries using the given reducer to combine values,
4361	>	* and the given basis as an identity value.
4362		*
4363	<	* @return  an enumeration of the keys in this table.
4364	<	* @see     Enumeration
4365	<	* @see     #elements()
4366	<	* @see     #keySet()
4367	<	* @see     Map
4363	>	* @param parallelismThreshold the (estimated) number of elements
4364	>	* needed for this operation to be executed in parallel
4365	>	* @param transformer a function returning the transformation
4366	>	* for an element
4367	>	* @param basis the identity (initial default value) for the reduction
4368	>	* @param reducer a commutative associative combining function
4369	>	* @return the result of accumulating the given transformation
4370	>	* of all entries
4371	>	* @since 1.8
4372		*/
4373	<	public Enumeration<K> keys() {
4374	<	return new KeyIterator();
4373	>	public int reduceEntriesToInt(long parallelismThreshold,
4374	>	ToIntFunction<Map.Entry<K,V>> transformer,
4375	>	int basis,
4376	>	IntBinaryOperator reducer) {
4377	>	if (transformer == null || reducer == null)
4378	>	throw new NullPointerException();
4379	>	return new MapReduceEntriesToIntTask<K,V>
4380	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4381	>	null, transformer, basis, reducer).invoke();
4382		}
4383
4384	+
4385	+	/* ----------------Views -------------- */
4386	+
4387		/**
4388	<	* Returns an enumeration of the values in this table.
4389	<	* Use the Enumeration methods on the returned object to fetch the elements
4390	<	* sequentially.
4388	>	* Base class for views.
4389	>	*/
4390	>	abstract static class CollectionView<K,V,E>
4391	>	implements Collection<E>, java.io.Serializable {
4392	>	private static final long serialVersionUID = 7249069246763182397L;
4393	>	final ConcurrentHashMap<K,V> map;
4394	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4395	>
4396	>	/**
4397	>	* Returns the map backing this view.
4398	>	*
4399	>	* @return the map backing this view
4400	>	*/
4401	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4402	>
4403	>	/**
4404	>	* Removes all of the elements from this view, by removing all
4405	>	* the mappings from the map backing this view.
4406	>	*/
4407	>	public final void clear()      { map.clear(); }
4408	>	public final int size()        { return map.size(); }
4409	>	public final boolean isEmpty() { return map.isEmpty(); }
4410	>
4411	>	// implementations below rely on concrete classes supplying these
4412	>	// abstract methods
4413	>	/**
4414	>	* Returns an iterator over the elements in this collection.
4415	>	*
4416	>	* <p>The returned iterator is
4417	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4418	>	*
4419	>	* @return an iterator over the elements in this collection
4420	>	*/
4421	>	public abstract Iterator<E> iterator();
4422	>	public abstract boolean contains(Object o);
4423	>	public abstract boolean remove(Object o);
4424	>
4425	>	private static final String OOME_MSG = "Required array size too large";
4426	>
4427	>	public final Object[] toArray() {
4428	>	long sz = map.mappingCount();
4429	>	if (sz > MAX_ARRAY_SIZE)
4430	>	throw new OutOfMemoryError(OOME_MSG);
4431	>	int n = (int)sz;
4432	>	Object[] r = new Object[n];
4433	>	int i = 0;
4434	>	for (E e : this) {
4435	>	if (i == n) {
4436	>	if (n >= MAX_ARRAY_SIZE)
4437	>	throw new OutOfMemoryError(OOME_MSG);
4438	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4439	>	n = MAX_ARRAY_SIZE;
4440	>	else
4441	>	n += (n >>> 1) + 1;
4442	>	r = Arrays.copyOf(r, n);
4443	>	}
4444	>	r[i++] = e;
4445	>	}
4446	>	return (i == n) ? r : Arrays.copyOf(r, i);
4447	>	}
4448	>
4449	>	@SuppressWarnings("unchecked")
4450	>	public final <T> T[] toArray(T[] a) {
4451	>	long sz = map.mappingCount();
4452	>	if (sz > MAX_ARRAY_SIZE)
4453	>	throw new OutOfMemoryError(OOME_MSG);
4454	>	int m = (int)sz;
4455	>	T[] r = (a.length >= m) ? a :
4456	>	(T[])java.lang.reflect.Array
4457	>	.newInstance(a.getClass().getComponentType(), m);
4458	>	int n = r.length;
4459	>	int i = 0;
4460	>	for (E e : this) {
4461	>	if (i == n) {
4462	>	if (n >= MAX_ARRAY_SIZE)
4463	>	throw new OutOfMemoryError(OOME_MSG);
4464	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4465	>	n = MAX_ARRAY_SIZE;
4466	>	else
4467	>	n += (n >>> 1) + 1;
4468	>	r = Arrays.copyOf(r, n);
4469	>	}
4470	>	r[i++] = (T)e;
4471	>	}
4472	>	if (a == r && i < n) {
4473	>	r[i] = null; // null-terminate
4474	>	return r;
4475	>	}
4476	>	return (i == n) ? r : Arrays.copyOf(r, i);
4477	>	}
4478	>
4479	>	/**
4480	>	* Returns a string representation of this collection.
4481	>	* The string representation consists of the string representations
4482	>	* of the collection's elements in the order they are returned by
4483	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4484	>	* Adjacent elements are separated by the characters {@code ", "}
4485	>	* (comma and space).  Elements are converted to strings as by
4486	>	* {@link String#valueOf(Object)}.
4487	>	*
4488	>	* @return a string representation of this collection
4489	>	*/
4490	>	public final String toString() {
4491	>	StringBuilder sb = new StringBuilder();
4492	>	sb.append('[');
4493	>	Iterator<E> it = iterator();
4494	>	if (it.hasNext()) {
4495	>	for (;;) {
4496	>	Object e = it.next();
4497	>	sb.append(e == this ? "(this Collection)" : e);
4498	>	if (!it.hasNext())
4499	>	break;
4500	>	sb.append(',').append(' ');
4501	>	}
4502	>	}
4503	>	return sb.append(']').toString();
4504	>	}
4505	>
4506	>	public final boolean containsAll(Collection<?> c) {
4507	>	if (c != this) {
4508	>	for (Object e : c) {
4509	>	if (e == null || !contains(e))
4510	>	return false;
4511	>	}
4512	>	}
4513	>	return true;
4514	>	}
4515	>
4516	>	public boolean removeAll(Collection<?> c) {
4517	>	if (c == null) throw new NullPointerException();
4518	>	boolean modified = false;
4519	>	// Use (c instanceof Set) as a hint that lookup in c is as
4520	>	// efficient as this view
4521	>	Node<K,V>[] t;
4522	>	if ((t = map.table) == null) {
4523	>	return false;
4524	>	} else if (c instanceof Set<?> && c.size() > t.length) {
4525	>	for (Iterator<?> it = iterator(); it.hasNext(); ) {
4526	>	if (c.contains(it.next())) {
4527	>	it.remove();
4528	>	modified = true;
4529	>	}
4530	>	}
4531	>	} else {
4532	>	for (Object e : c)
4533	>	modified |= remove(e);
4534	>	}
4535	>	return modified;
4536	>	}
4537	>
4538	>	public final boolean retainAll(Collection<?> c) {
4539	>	if (c == null) throw new NullPointerException();
4540	>	boolean modified = false;
4541	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4542	>	if (!c.contains(it.next())) {
4543	>	it.remove();
4544	>	modified = true;
4545	>	}
4546	>	}
4547	>	return modified;
4548	>	}
4549	>
4550	>	}
4551	>
4552	>	/**
4553	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4554	>	* which additions may optionally be enabled by mapping to a
4555	>	* common value.  This class cannot be directly instantiated.
4556	>	* See {@link #keySet() keySet()},
4557	>	* {@link #keySet(Object) keySet(V)},
4558	>	* {@link #newKeySet() newKeySet()},
4559	>	* {@link #newKeySet(int) newKeySet(int)}.
4560		*
4561	<	* @return  an enumeration of the values in this table.
853	<	* @see     java.util.Enumeration
854	<	* @see     #keys()
855	<	* @see     #values()
856	<	* @see     Map
4561	>	* @since 1.8
4562		*/
4563	<	public Enumeration<V> elements() {
4564	<	return new ValueIterator();
4563	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4564	>	implements Set<K>, java.io.Serializable {
4565	>	private static final long serialVersionUID = 7249069246763182397L;
4566	>	private final V value;
4567	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4568	>	super(map);
4569	>	this.value = value;
4570	>	}
4571	>
4572	>	/**
4573	>	* Returns the default mapped value for additions,
4574	>	* or {@code null} if additions are not supported.
4575	>	*
4576	>	* @return the default mapped value for additions, or {@code null}
4577	>	* if not supported
4578	>	*/
4579	>	public V getMappedValue() { return value; }
4580	>
4581	>	/**
4582	>	* {@inheritDoc}
4583	>	* @throws NullPointerException if the specified key is null
4584	>	*/
4585	>	public boolean contains(Object o) { return map.containsKey(o); }
4586	>
4587	>	/**
4588	>	* Removes the key from this map view, by removing the key (and its
4589	>	* corresponding value) from the backing map.  This method does
4590	>	* nothing if the key is not in the map.
4591	>	*
4592	>	* @param  o the key to be removed from the backing map
4593	>	* @return {@code true} if the backing map contained the specified key
4594	>	* @throws NullPointerException if the specified key is null
4595	>	*/
4596	>	public boolean remove(Object o) { return map.remove(o) != null; }
4597	>
4598	>	/**
4599	>	* @return an iterator over the keys of the backing map
4600	>	*/
4601	>	public Iterator<K> iterator() {
4602	>	Node<K,V>[] t;
4603	>	ConcurrentHashMap<K,V> m = map;
4604	>	int f = (t = m.table) == null ? 0 : t.length;
4605	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4606	>	}
4607	>
4608	>	/**
4609	>	* Adds the specified key to this set view by mapping the key to
4610	>	* the default mapped value in the backing map, if defined.
4611	>	*
4612	>	* @param e key to be added
4613	>	* @return {@code true} if this set changed as a result of the call
4614	>	* @throws NullPointerException if the specified key is null
4615	>	* @throws UnsupportedOperationException if no default mapped value
4616	>	* for additions was provided
4617	>	*/
4618	>	public boolean add(K e) {
4619	>	V v;
4620	>	if ((v = value) == null)
4621	>	throw new UnsupportedOperationException();
4622	>	return map.putVal(e, v, true) == null;
4623	>	}
4624	>
4625	>	/**
4626	>	* Adds all of the elements in the specified collection to this set,
4627	>	* as if by calling {@link #add} on each one.
4628	>	*
4629	>	* @param c the elements to be inserted into this set
4630	>	* @return {@code true} if this set changed as a result of the call
4631	>	* @throws NullPointerException if the collection or any of its
4632	>	* elements are {@code null}
4633	>	* @throws UnsupportedOperationException if no default mapped value
4634	>	* for additions was provided
4635	>	*/
4636	>	public boolean addAll(Collection<? extends K> c) {
4637	>	boolean added = false;
4638	>	V v;
4639	>	if ((v = value) == null)
4640	>	throw new UnsupportedOperationException();
4641	>	for (K e : c) {
4642	>	if (map.putVal(e, v, true) == null)
4643	>	added = true;
4644	>	}
4645	>	return added;
4646	>	}
4647	>
4648	>	public int hashCode() {
4649	>	int h = 0;
4650	>	for (K e : this)
4651	>	h += e.hashCode();
4652	>	return h;
4653	>	}
4654	>
4655	>	public boolean equals(Object o) {
4656	>	Set<?> c;
4657	>	return ((o instanceof Set) &&
4658	>	((c = (Set<?>)o) == this ||
4659	>	(containsAll(c) && c.containsAll(this))));
4660	>	}
4661	>
4662	>	public Spliterator<K> spliterator() {
4663	>	Node<K,V>[] t;
4664	>	ConcurrentHashMap<K,V> m = map;
4665	>	long n = m.sumCount();
4666	>	int f = (t = m.table) == null ? 0 : t.length;
4667	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4668	>	}
4669	>
4670	>	public void forEach(Consumer<? super K> action) {
4671	>	if (action == null) throw new NullPointerException();
4672	>	Node<K,V>[] t;
4673	>	if ((t = map.table) != null) {
4674	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4675	>	for (Node<K,V> p; (p = it.advance()) != null; )
4676	>	action.accept(p.key);
4677	>	}
4678	>	}
4679	>	}
4680	>
4681	>	/**
4682	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4683	>	* values, in which additions are disabled. This class cannot be
4684	>	* directly instantiated. See {@link #values()}.
4685	>	*/
4686	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4687	>	implements Collection<V>, java.io.Serializable {
4688	>	private static final long serialVersionUID = 2249069246763182397L;
4689	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4690	>	public final boolean contains(Object o) {
4691	>	return map.containsValue(o);
4692	>	}
4693	>
4694	>	public final boolean remove(Object o) {
4695	>	if (o != null) {
4696	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4697	>	if (o.equals(it.next())) {
4698	>	it.remove();
4699	>	return true;
4700	>	}
4701	>	}
4702	>	}
4703	>	return false;
4704	>	}
4705	>
4706	>	public final Iterator<V> iterator() {
4707	>	ConcurrentHashMap<K,V> m = map;
4708	>	Node<K,V>[] t;
4709	>	int f = (t = m.table) == null ? 0 : t.length;
4710	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4711	>	}
4712	>
4713	>	public final boolean add(V e) {
4714	>	throw new UnsupportedOperationException();
4715	>	}
4716	>	public final boolean addAll(Collection<? extends V> c) {
4717	>	throw new UnsupportedOperationException();
4718	>	}
4719	>
4720	>	@Override public boolean removeAll(Collection<?> c) {
4721	>	if (c == null) throw new NullPointerException();
4722	>	boolean modified = false;
4723	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4724	>	if (c.contains(it.next())) {
4725	>	it.remove();
4726	>	modified = true;
4727	>	}
4728	>	}
4729	>	return modified;
4730	>	}
4731	>
4732	>	public boolean removeIf(Predicate<? super V> filter) {
4733	>	return map.removeValueIf(filter);
4734	>	}
4735	>
4736	>	public Spliterator<V> spliterator() {
4737	>	Node<K,V>[] t;
4738	>	ConcurrentHashMap<K,V> m = map;
4739	>	long n = m.sumCount();
4740	>	int f = (t = m.table) == null ? 0 : t.length;
4741	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4742	>	}
4743	>
4744	>	public void forEach(Consumer<? super V> action) {
4745	>	if (action == null) throw new NullPointerException();
4746	>	Node<K,V>[] t;
4747	>	if ((t = map.table) != null) {
4748	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4749	>	for (Node<K,V> p; (p = it.advance()) != null; )
4750	>	action.accept(p.val);
4751	>	}
4752	>	}
4753		}
4754
4755	<	/* ---------------- Iterator Support -------------- */
4755	>	/**
4756	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4757	>	* entries.  This class cannot be directly instantiated. See
4758	>	* {@link #entrySet()}.
4759	>	*/
4760	>	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4761	>	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4762	>	private static final long serialVersionUID = 2249069246763182397L;
4763	>	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4764	>
4765	>	public boolean contains(Object o) {
4766	>	Object k, v, r; Map.Entry<?,?> e;
4767	>	return ((o instanceof Map.Entry) &&
4768	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4769	>	(r = map.get(k)) != null &&
4770	>	(v = e.getValue()) != null &&
4771	>	(v == r || v.equals(r)));
4772	>	}
4773
4774	<	private abstract class HashIterator {
4775	<	private int nextSegmentIndex;
4776	<	private int nextTableIndex;
4777	<	private HashEntry[] currentTable;
4778	<	private HashEntry<K, V> nextEntry;
4779	<	private HashEntry<K, V> lastReturned;
4774	>	public boolean remove(Object o) {
4775	>	Object k, v; Map.Entry<?,?> e;
4776	>	return ((o instanceof Map.Entry) &&
4777	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4778	>	(v = e.getValue()) != null &&
4779	>	map.remove(k, v));
4780	>	}
4781
4782	<	private HashIterator() {
4783	<	nextSegmentIndex = segments.length - 1;
4784	<	nextTableIndex = -1;
4785	<	advance();
4782	>	/**
4783	>	* @return an iterator over the entries of the backing map
4784	>	*/
4785	>	public Iterator<Map.Entry<K,V>> iterator() {
4786	>	ConcurrentHashMap<K,V> m = map;
4787	>	Node<K,V>[] t;
4788	>	int f = (t = m.table) == null ? 0 : t.length;
4789	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4790	>	}
4791	>
4792	>	public boolean add(Entry<K,V> e) {
4793	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4794		}
4795
4796	<	public boolean hasMoreElements() { return hasNext(); }
4796	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4797	>	boolean added = false;
4798	>	for (Entry<K,V> e : c) {
4799	>	if (add(e))
4800	>	added = true;
4801	>	}
4802	>	return added;
4803	>	}
4804
4805	<	private void advance() {
4806	<	if (nextEntry != null && (nextEntry = nextEntry.next) != null)
4807	<	return;
4805	>	public boolean removeIf(Predicate<? super Entry<K,V>> filter) {
4806	>	return map.removeEntryIf(filter);
4807	>	}
4808
4809	<	while (nextTableIndex >= 0) {
4810	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[nextTableIndex--]) != null)
4811	<	return;
4809	>	public final int hashCode() {
4810	>	int h = 0;
4811	>	Node<K,V>[] t;
4812	>	if ((t = map.table) != null) {
4813	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4814	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4815	>	h += p.hashCode();
4816	>	}
4817		}
4818	+	return h;
4819	+	}
4820
4821	<	while (nextSegmentIndex >= 0) {
4822	<	Segment<K,V> seg = (Segment<K,V>)segments[nextSegmentIndex--];
4823	<	if (seg.count != 0) {
4824	<	currentTable = seg.table;
4825	<	for (int j = currentTable.length - 1; j >= 0; --j) {
4826	<	if ( (nextEntry = (HashEntry<K,V>)currentTable[j]) != null) {
4827	<	nextTableIndex = j - 1;
4828	<	return;
4829	<	}
4821	>	public final boolean equals(Object o) {
4822	>	Set<?> c;
4823	>	return ((o instanceof Set) &&
4824	>	((c = (Set<?>)o) == this ||
4825	>	(containsAll(c) && c.containsAll(this))));
4826	>	}
4827	>
4828	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4829	>	Node<K,V>[] t;
4830	>	ConcurrentHashMap<K,V> m = map;
4831	>	long n = m.sumCount();
4832	>	int f = (t = m.table) == null ? 0 : t.length;
4833	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4834	>	}
4835	>
4836	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4837	>	if (action == null) throw new NullPointerException();
4838	>	Node<K,V>[] t;
4839	>	if ((t = map.table) != null) {
4840	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4841	>	for (Node<K,V> p; (p = it.advance()) != null; )
4842	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4843	>	}
4844	>	}
4845	>
4846	>	}
4847	>
4848	>	// -------------------------------------------------------
4849	>
4850	>	/**
4851	>	* Base class for bulk tasks. Repeats some fields and code from
4852	>	* class Traverser, because we need to subclass CountedCompleter.
4853	>	*/
4854	>	@SuppressWarnings("serial")
4855	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4856	>	Node<K,V>[] tab;        // same as Traverser
4857	>	Node<K,V> next;
4858	>	TableStack<K,V> stack, spare;
4859	>	int index;
4860	>	int baseIndex;
4861	>	int baseLimit;
4862	>	final int baseSize;
4863	>	int batch;              // split control
4864	>
4865	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4866	>	super(par);
4867	>	this.batch = b;
4868	>	this.index = this.baseIndex = i;
4869	>	if ((this.tab = t) == null)
4870	>	this.baseSize = this.baseLimit = 0;
4871	>	else if (par == null)
4872	>	this.baseSize = this.baseLimit = t.length;
4873	>	else {
4874	>	this.baseLimit = f;
4875	>	this.baseSize = par.baseSize;
4876	>	}
4877	>	}
4878	>
4879	>	/**
4880	>	* Same as Traverser version.
4881	>	*/
4882	>	final Node<K,V> advance() {
4883	>	Node<K,V> e;
4884	>	if ((e = next) != null)
4885	>	e = e.next;
4886	>	for (;;) {
4887	>	Node<K,V>[] t; int i, n;
4888	>	if (e != null)
4889	>	return next = e;
4890	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4891	>	(n = t.length) <= (i = index) || i < 0)
4892	>	return next = null;
4893	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4894	>	if (e instanceof ForwardingNode) {
4895	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4896	>	e = null;
4897	>	pushState(t, i, n);
4898	>	continue;
4899		}
4900	+	else if (e instanceof TreeBin)
4901	+	e = ((TreeBin<K,V>)e).first;
4902	+	else
4903	+	e = null;
4904		}
4905	+	if (stack != null)
4906	+	recoverState(n);
4907	+	else if ((index = i + baseSize) >= n)
4908	+	index = ++baseIndex;
4909		}
4910		}
4911
4912	<	public boolean hasNext() { return nextEntry != null; }
4912	>	private void pushState(Node<K,V>[] t, int i, int n) {
4913	>	TableStack<K,V> s = spare;
4914	>	if (s != null)
4915	>	spare = s.next;
4916	>	else
4917	>	s = new TableStack<K,V>();
4918	>	s.tab = t;
4919	>	s.length = n;
4920	>	s.index = i;
4921	>	s.next = stack;
4922	>	stack = s;
4923	>	}
4924
4925	<	HashEntry<K,V> nextEntry() {
4926	<	if (nextEntry == null)
4927	<	throw new NoSuchElementException();
4928	<	lastReturned = nextEntry;
4929	<	advance();
4930	<	return lastReturned;
4925	>	private void recoverState(int n) {
4926	>	TableStack<K,V> s; int len;
4927	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4928	>	n = len;
4929	>	index = s.index;
4930	>	tab = s.tab;
4931	>	s.tab = null;
4932	>	TableStack<K,V> next = s.next;
4933	>	s.next = spare; // save for reuse
4934	>	stack = next;
4935	>	spare = s;
4936	>	}
4937	>	if (s == null && (index += baseSize) >= n)
4938	>	index = ++baseIndex;
4939		}
4940	+	}
4941
4942	<	public void remove() {
4943	<	if (lastReturned == null)
4944	<	throw new IllegalStateException();
4945	<	ConcurrentHashMap.this.remove(lastReturned.key);
4946	<	lastReturned = null;
4942	>	/*
4943	>	* Task classes. Coded in a regular but ugly format/style to
4944	>	* simplify checks that each variant differs in the right way from
4945	>	* others. The null screenings exist because compilers cannot tell
4946	>	* that we've already null-checked task arguments, so we force
4947	>	* simplest hoisted bypass to help avoid convoluted traps.
4948	>	*/
4949	>	@SuppressWarnings("serial")
4950	>	static final class ForEachKeyTask<K,V>
4951	>	extends BulkTask<K,V,Void> {
4952	>	final Consumer<? super K> action;
4953	>	ForEachKeyTask
4954	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4955	>	Consumer<? super K> action) {
4956	>	super(p, b, i, f, t);
4957	>	this.action = action;
4958	>	}
4959	>	public final void compute() {
4960	>	final Consumer<? super K> action;
4961	>	if ((action = this.action) != null) {
4962	>	for (int i = baseIndex, f, h; batch > 0 &&
4963	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4964	>	addToPendingCount(1);
4965	>	new ForEachKeyTask<K,V>
4966	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4967	>	action).fork();
4968	>	}
4969	>	for (Node<K,V> p; (p = advance()) != null;)
4970	>	action.accept(p.key);
4971	>	propagateCompletion();
4972	>	}
4973		}
4974		}
4975
4976	<	private class KeyIterator extends HashIterator implements Iterator<K>, Enumeration<K> {
4977	<	public K next() { return super.nextEntry().key; }
4978	<	public K nextElement() { return super.nextEntry().key; }
4976	>	@SuppressWarnings("serial")
4977	>	static final class ForEachValueTask<K,V>
4978	>	extends BulkTask<K,V,Void> {
4979	>	final Consumer<? super V> action;
4980	>	ForEachValueTask
4981	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4982	>	Consumer<? super V> action) {
4983	>	super(p, b, i, f, t);
4984	>	this.action = action;
4985	>	}
4986	>	public final void compute() {
4987	>	final Consumer<? super V> action;
4988	>	if ((action = this.action) != null) {
4989	>	for (int i = baseIndex, f, h; batch > 0 &&
4990	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4991	>	addToPendingCount(1);
4992	>	new ForEachValueTask<K,V>
4993	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4994	>	action).fork();
4995	>	}
4996	>	for (Node<K,V> p; (p = advance()) != null;)
4997	>	action.accept(p.val);
4998	>	propagateCompletion();
4999	>	}
5000	>	}
5001		}
5002
5003	<	private class ValueIterator extends HashIterator implements Iterator<V>, Enumeration<V> {
5004	<	public V next() { return super.nextEntry().value; }
5005	<	public V nextElement() { return super.nextEntry().value; }
5003	>	@SuppressWarnings("serial")
5004	>	static final class ForEachEntryTask<K,V>
5005	>	extends BulkTask<K,V,Void> {
5006	>	final Consumer<? super Entry<K,V>> action;
5007	>	ForEachEntryTask
5008	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5009	>	Consumer<? super Entry<K,V>> action) {
5010	>	super(p, b, i, f, t);
5011	>	this.action = action;
5012	>	}
5013	>	public final void compute() {
5014	>	final Consumer<? super Entry<K,V>> action;
5015	>	if ((action = this.action) != null) {
5016	>	for (int i = baseIndex, f, h; batch > 0 &&
5017	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5018	>	addToPendingCount(1);
5019	>	new ForEachEntryTask<K,V>
5020	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5021	>	action).fork();
5022	>	}
5023	>	for (Node<K,V> p; (p = advance()) != null; )
5024	>	action.accept(p);
5025	>	propagateCompletion();
5026	>	}
5027	>	}
5028		}
5029
5030	<	private class EntryIterator extends HashIterator implements Iterator<Entry<K,V>> {
5031	<	public Map.Entry<K,V> next() { return super.nextEntry(); }
5030	>	@SuppressWarnings("serial")
5031	>	static final class ForEachMappingTask<K,V>
5032	>	extends BulkTask<K,V,Void> {
5033	>	final BiConsumer<? super K, ? super V> action;
5034	>	ForEachMappingTask
5035	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5036	>	BiConsumer<? super K,? super V> action) {
5037	>	super(p, b, i, f, t);
5038	>	this.action = action;
5039	>	}
5040	>	public final void compute() {
5041	>	final BiConsumer<? super K, ? super V> action;
5042	>	if ((action = this.action) != null) {
5043	>	for (int i = baseIndex, f, h; batch > 0 &&
5044	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5045	>	addToPendingCount(1);
5046	>	new ForEachMappingTask<K,V>
5047	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5048	>	action).fork();
5049	>	}
5050	>	for (Node<K,V> p; (p = advance()) != null; )
5051	>	action.accept(p.key, p.val);
5052	>	propagateCompletion();
5053	>	}
5054	>	}
5055		}
5056
5057	<	private class KeySet extends AbstractSet<K> {
5058	<	public Iterator<K> iterator() {
5059	<	return new KeyIterator();
5057	>	@SuppressWarnings("serial")
5058	>	static final class ForEachTransformedKeyTask<K,V,U>
5059	>	extends BulkTask<K,V,Void> {
5060	>	final Function<? super K, ? extends U> transformer;
5061	>	final Consumer<? super U> action;
5062	>	ForEachTransformedKeyTask
5063	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5064	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
5065	>	super(p, b, i, f, t);
5066	>	this.transformer = transformer; this.action = action;
5067		}
5068	<	public int size() {
5069	<	return ConcurrentHashMap.this.size();
5068	>	public final void compute() {
5069	>	final Function<? super K, ? extends U> transformer;
5070	>	final Consumer<? super U> action;
5071	>	if ((transformer = this.transformer) != null &&
5072	>	(action = this.action) != null) {
5073	>	for (int i = baseIndex, f, h; batch > 0 &&
5074	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5075	>	addToPendingCount(1);
5076	>	new ForEachTransformedKeyTask<K,V,U>
5077	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5078	>	transformer, action).fork();
5079	>	}
5080	>	for (Node<K,V> p; (p = advance()) != null; ) {
5081	>	U u;
5082	>	if ((u = transformer.apply(p.key)) != null)
5083	>	action.accept(u);
5084	>	}
5085	>	propagateCompletion();
5086	>	}
5087		}
5088	<	public boolean contains(Object o) {
5089	<	return ConcurrentHashMap.this.containsKey(o);
5088	>	}
5089	>
5090	>	@SuppressWarnings("serial")
5091	>	static final class ForEachTransformedValueTask<K,V,U>
5092	>	extends BulkTask<K,V,Void> {
5093	>	final Function<? super V, ? extends U> transformer;
5094	>	final Consumer<? super U> action;
5095	>	ForEachTransformedValueTask
5096	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5097	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5098	>	super(p, b, i, f, t);
5099	>	this.transformer = transformer; this.action = action;
5100		}
5101	<	public boolean remove(Object o) {
5102	<	return ConcurrentHashMap.this.remove(o) != null;
5101	>	public final void compute() {
5102	>	final Function<? super V, ? extends U> transformer;
5103	>	final Consumer<? super U> action;
5104	>	if ((transformer = this.transformer) != null &&
5105	>	(action = this.action) != null) {
5106	>	for (int i = baseIndex, f, h; batch > 0 &&
5107	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5108	>	addToPendingCount(1);
5109	>	new ForEachTransformedValueTask<K,V,U>
5110	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5111	>	transformer, action).fork();
5112	>	}
5113	>	for (Node<K,V> p; (p = advance()) != null; ) {
5114	>	U u;
5115	>	if ((u = transformer.apply(p.val)) != null)
5116	>	action.accept(u);
5117	>	}
5118	>	propagateCompletion();
5119	>	}
5120		}
5121	<	public void clear() {
5122	<	ConcurrentHashMap.this.clear();
5121	>	}
5122	>
5123	>	@SuppressWarnings("serial")
5124	>	static final class ForEachTransformedEntryTask<K,V,U>
5125	>	extends BulkTask<K,V,Void> {
5126	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5127	>	final Consumer<? super U> action;
5128	>	ForEachTransformedEntryTask
5129	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5130	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5131	>	super(p, b, i, f, t);
5132	>	this.transformer = transformer; this.action = action;
5133	>	}
5134	>	public final void compute() {
5135	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5136	>	final Consumer<? super U> action;
5137	>	if ((transformer = this.transformer) != null &&
5138	>	(action = this.action) != null) {
5139	>	for (int i = baseIndex, f, h; batch > 0 &&
5140	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5141	>	addToPendingCount(1);
5142	>	new ForEachTransformedEntryTask<K,V,U>
5143	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5144	>	transformer, action).fork();
5145	>	}
5146	>	for (Node<K,V> p; (p = advance()) != null; ) {
5147	>	U u;
5148	>	if ((u = transformer.apply(p)) != null)
5149	>	action.accept(u);
5150	>	}
5151	>	propagateCompletion();
5152	>	}
5153		}
5154		}
5155
5156	<	private class Values extends AbstractCollection<V> {
5157	<	public Iterator<V> iterator() {
5158	<	return new ValueIterator();
5156	>	@SuppressWarnings("serial")
5157	>	static final class ForEachTransformedMappingTask<K,V,U>
5158	>	extends BulkTask<K,V,Void> {
5159	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5160	>	final Consumer<? super U> action;
5161	>	ForEachTransformedMappingTask
5162	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5163	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5164	>	Consumer<? super U> action) {
5165	>	super(p, b, i, f, t);
5166	>	this.transformer = transformer; this.action = action;
5167		}
5168	<	public int size() {
5169	<	return ConcurrentHashMap.this.size();
5168	>	public final void compute() {
5169	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5170	>	final Consumer<? super U> action;
5171	>	if ((transformer = this.transformer) != null &&
5172	>	(action = this.action) != null) {
5173	>	for (int i = baseIndex, f, h; batch > 0 &&
5174	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5175	>	addToPendingCount(1);
5176	>	new ForEachTransformedMappingTask<K,V,U>
5177	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5178	>	transformer, action).fork();
5179	>	}
5180	>	for (Node<K,V> p; (p = advance()) != null; ) {
5181	>	U u;
5182	>	if ((u = transformer.apply(p.key, p.val)) != null)
5183	>	action.accept(u);
5184	>	}
5185	>	propagateCompletion();
5186	>	}
5187		}
5188	<	public boolean contains(Object o) {
5189	<	return ConcurrentHashMap.this.containsValue(o);
5188	>	}
5189	>
5190	>	@SuppressWarnings("serial")
5191	>	static final class SearchKeysTask<K,V,U>
5192	>	extends BulkTask<K,V,U> {
5193	>	final Function<? super K, ? extends U> searchFunction;
5194	>	final AtomicReference<U> result;
5195	>	SearchKeysTask
5196	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5197	>	Function<? super K, ? extends U> searchFunction,
5198	>	AtomicReference<U> result) {
5199	>	super(p, b, i, f, t);
5200	>	this.searchFunction = searchFunction; this.result = result;
5201		}
5202	<	public void clear() {
5203	<	ConcurrentHashMap.this.clear();
5202	>	public final U getRawResult() { return result.get(); }
5203	>	public final void compute() {
5204	>	final Function<? super K, ? extends U> searchFunction;
5205	>	final AtomicReference<U> result;
5206	>	if ((searchFunction = this.searchFunction) != null &&
5207	>	(result = this.result) != null) {
5208	>	for (int i = baseIndex, f, h; batch > 0 &&
5209	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5210	>	if (result.get() != null)
5211	>	return;
5212	>	addToPendingCount(1);
5213	>	new SearchKeysTask<K,V,U>
5214	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5215	>	searchFunction, result).fork();
5216	>	}
5217	>	while (result.get() == null) {
5218	>	U u;
5219	>	Node<K,V> p;
5220	>	if ((p = advance()) == null) {
5221	>	propagateCompletion();
5222	>	break;
5223	>	}
5224	>	if ((u = searchFunction.apply(p.key)) != null) {
5225	>	if (result.compareAndSet(null, u))
5226	>	quietlyCompleteRoot();
5227	>	break;
5228	>	}
5229	>	}
5230	>	}
5231		}
5232		}
5233
5234	<	private class EntrySet extends AbstractSet<Map.Entry<K,V>> {
5235	<	public Iterator<Map.Entry<K,V>> iterator() {
5236	<	return new EntryIterator();
5234	>	@SuppressWarnings("serial")
5235	>	static final class SearchValuesTask<K,V,U>
5236	>	extends BulkTask<K,V,U> {
5237	>	final Function<? super V, ? extends U> searchFunction;
5238	>	final AtomicReference<U> result;
5239	>	SearchValuesTask
5240	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5241	>	Function<? super V, ? extends U> searchFunction,
5242	>	AtomicReference<U> result) {
5243	>	super(p, b, i, f, t);
5244	>	this.searchFunction = searchFunction; this.result = result;
5245		}
5246	<	public boolean contains(Object o) {
5247	<	if (!(o instanceof Map.Entry))
5248	<	return false;
5249	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5250	<	V v = ConcurrentHashMap.this.get(e.getKey());
5251	<	return v != null && v.equals(e.getValue());
5246	>	public final U getRawResult() { return result.get(); }
5247	>	public final void compute() {
5248	>	final Function<? super V, ? extends U> searchFunction;
5249	>	final AtomicReference<U> result;
5250	>	if ((searchFunction = this.searchFunction) != null &&
5251	>	(result = this.result) != null) {
5252	>	for (int i = baseIndex, f, h; batch > 0 &&
5253	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5254	>	if (result.get() != null)
5255	>	return;
5256	>	addToPendingCount(1);
5257	>	new SearchValuesTask<K,V,U>
5258	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5259	>	searchFunction, result).fork();
5260	>	}
5261	>	while (result.get() == null) {
5262	>	U u;
5263	>	Node<K,V> p;
5264	>	if ((p = advance()) == null) {
5265	>	propagateCompletion();
5266	>	break;
5267	>	}
5268	>	if ((u = searchFunction.apply(p.val)) != null) {
5269	>	if (result.compareAndSet(null, u))
5270	>	quietlyCompleteRoot();
5271	>	break;
5272	>	}
5273	>	}
5274	>	}
5275		}
5276	<	public boolean remove(Object o) {
5277	<	if (!(o instanceof Map.Entry))
5278	<	return false;
5279	<	Map.Entry<K,V> e = (Map.Entry<K,V>)o;
5280	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
5276	>	}
5277	>
5278	>	@SuppressWarnings("serial")
5279	>	static final class SearchEntriesTask<K,V,U>
5280	>	extends BulkTask<K,V,U> {
5281	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5282	>	final AtomicReference<U> result;
5283	>	SearchEntriesTask
5284	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5285	>	Function<Entry<K,V>, ? extends U> searchFunction,
5286	>	AtomicReference<U> result) {
5287	>	super(p, b, i, f, t);
5288	>	this.searchFunction = searchFunction; this.result = result;
5289		}
5290	<	public int size() {
5291	<	return ConcurrentHashMap.this.size();
5290	>	public final U getRawResult() { return result.get(); }
5291	>	public final void compute() {
5292	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5293	>	final AtomicReference<U> result;
5294	>	if ((searchFunction = this.searchFunction) != null &&
5295	>	(result = this.result) != null) {
5296	>	for (int i = baseIndex, f, h; batch > 0 &&
5297	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5298	>	if (result.get() != null)
5299	>	return;
5300	>	addToPendingCount(1);
5301	>	new SearchEntriesTask<K,V,U>
5302	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5303	>	searchFunction, result).fork();
5304	>	}
5305	>	while (result.get() == null) {
5306	>	U u;
5307	>	Node<K,V> p;
5308	>	if ((p = advance()) == null) {
5309	>	propagateCompletion();
5310	>	break;
5311	>	}
5312	>	if ((u = searchFunction.apply(p)) != null) {
5313	>	if (result.compareAndSet(null, u))
5314	>	quietlyCompleteRoot();
5315	>	return;
5316	>	}
5317	>	}
5318	>	}
5319	>	}
5320	>	}
5321	>
5322	>	@SuppressWarnings("serial")
5323	>	static final class SearchMappingsTask<K,V,U>
5324	>	extends BulkTask<K,V,U> {
5325	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5326	>	final AtomicReference<U> result;
5327	>	SearchMappingsTask
5328	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5329	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5330	>	AtomicReference<U> result) {
5331	>	super(p, b, i, f, t);
5332	>	this.searchFunction = searchFunction; this.result = result;
5333		}
5334	<	public void clear() {
5335	<	ConcurrentHashMap.this.clear();
5334	>	public final U getRawResult() { return result.get(); }
5335	>	public final void compute() {
5336	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5337	>	final AtomicReference<U> result;
5338	>	if ((searchFunction = this.searchFunction) != null &&
5339	>	(result = this.result) != null) {
5340	>	for (int i = baseIndex, f, h; batch > 0 &&
5341	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5342	>	if (result.get() != null)
5343	>	return;
5344	>	addToPendingCount(1);
5345	>	new SearchMappingsTask<K,V,U>
5346	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5347	>	searchFunction, result).fork();
5348	>	}
5349	>	while (result.get() == null) {
5350	>	U u;
5351	>	Node<K,V> p;
5352	>	if ((p = advance()) == null) {
5353	>	propagateCompletion();
5354	>	break;
5355	>	}
5356	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5357	>	if (result.compareAndSet(null, u))
5358	>	quietlyCompleteRoot();
5359	>	break;
5360	>	}
5361	>	}
5362	>	}
5363		}
5364		}
5365
5366	<	/* ---------------- Serialization Support -------------- */
5366	>	@SuppressWarnings("serial")
5367	>	static final class ReduceKeysTask<K,V>
5368	>	extends BulkTask<K,V,K> {
5369	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5370	>	K result;
5371	>	ReduceKeysTask<K,V> rights, nextRight;
5372	>	ReduceKeysTask
5373	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5374	>	ReduceKeysTask<K,V> nextRight,
5375	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5376	>	super(p, b, i, f, t); this.nextRight = nextRight;
5377	>	this.reducer = reducer;
5378	>	}
5379	>	public final K getRawResult() { return result; }
5380	>	public final void compute() {
5381	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5382	>	if ((reducer = this.reducer) != null) {
5383	>	for (int i = baseIndex, f, h; batch > 0 &&
5384	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5385	>	addToPendingCount(1);
5386	>	(rights = new ReduceKeysTask<K,V>
5387	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5388	>	rights, reducer)).fork();
5389	>	}
5390	>	K r = null;
5391	>	for (Node<K,V> p; (p = advance()) != null; ) {
5392	>	K u = p.key;
5393	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5394	>	}
5395	>	result = r;
5396	>	CountedCompleter<?> c;
5397	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5398	>	@SuppressWarnings("unchecked")
5399	>	ReduceKeysTask<K,V>
5400	>	t = (ReduceKeysTask<K,V>)c,
5401	>	s = t.rights;
5402	>	while (s != null) {
5403	>	K tr, sr;
5404	>	if ((sr = s.result) != null)
5405	>	t.result = (((tr = t.result) == null) ? sr :
5406	>	reducer.apply(tr, sr));
5407	>	s = t.rights = s.nextRight;
5408	>	}
5409	>	}
5410	>	}
5411	>	}
5412	>	}
5413
5414	<	/**
5415	<	* Save the state of the <tt>ConcurrentHashMap</tt>
5416	<	* instance to a stream (i.e.,
5417	<	* serialize it).
5418	<	* @param s the stream
5419	<	* @serialData
5420	<	* the key (Object) and value (Object)
5421	<	* for each key-value mapping, followed by a null pair.
5422	<	* The key-value mappings are emitted in no particular order.
5423	<	*/
5424	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException  {
5425	<	s.defaultWriteObject();
5414	>	@SuppressWarnings("serial")
5415	>	static final class ReduceValuesTask<K,V>
5416	>	extends BulkTask<K,V,V> {
5417	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5418	>	V result;
5419	>	ReduceValuesTask<K,V> rights, nextRight;
5420	>	ReduceValuesTask
5421	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5422	>	ReduceValuesTask<K,V> nextRight,
5423	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5424	>	super(p, b, i, f, t); this.nextRight = nextRight;
5425	>	this.reducer = reducer;
5426	>	}
5427	>	public final V getRawResult() { return result; }
5428	>	public final void compute() {
5429	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5430	>	if ((reducer = this.reducer) != null) {
5431	>	for (int i = baseIndex, f, h; batch > 0 &&
5432	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5433	>	addToPendingCount(1);
5434	>	(rights = new ReduceValuesTask<K,V>
5435	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5436	>	rights, reducer)).fork();
5437	>	}
5438	>	V r = null;
5439	>	for (Node<K,V> p; (p = advance()) != null; ) {
5440	>	V v = p.val;
5441	>	r = (r == null) ? v : reducer.apply(r, v);
5442	>	}
5443	>	result = r;
5444	>	CountedCompleter<?> c;
5445	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5446	>	@SuppressWarnings("unchecked")
5447	>	ReduceValuesTask<K,V>
5448	>	t = (ReduceValuesTask<K,V>)c,
5449	>	s = t.rights;
5450	>	while (s != null) {
5451	>	V tr, sr;
5452	>	if ((sr = s.result) != null)
5453	>	t.result = (((tr = t.result) == null) ? sr :
5454	>	reducer.apply(tr, sr));
5455	>	s = t.rights = s.nextRight;
5456	>	}
5457	>	}
5458	>	}
5459	>	}
5460	>	}
5461
5462	<	for (int k = 0; k < segments.length; ++k) {
5463	<	Segment<K,V> seg = (Segment<K,V>)segments[k];
5464	<	seg.lock();
5465	<	try {
5466	<	HashEntry[] tab = seg.table;
5467	<	for (int i = 0; i < tab.length; ++i) {
5468	<	for (HashEntry<K,V> e = (HashEntry<K,V>)tab[i]; e != null; e = e.next) {
5469	<	s.writeObject(e.key);
5470	<	s.writeObject(e.value);
5462	>	@SuppressWarnings("serial")
5463	>	static final class ReduceEntriesTask<K,V>
5464	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5465	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5466	>	Map.Entry<K,V> result;
5467	>	ReduceEntriesTask<K,V> rights, nextRight;
5468	>	ReduceEntriesTask
5469	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5470	>	ReduceEntriesTask<K,V> nextRight,
5471	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5472	>	super(p, b, i, f, t); this.nextRight = nextRight;
5473	>	this.reducer = reducer;
5474	>	}
5475	>	public final Map.Entry<K,V> getRawResult() { return result; }
5476	>	public final void compute() {
5477	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5478	>	if ((reducer = this.reducer) != null) {
5479	>	for (int i = baseIndex, f, h; batch > 0 &&
5480	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5481	>	addToPendingCount(1);
5482	>	(rights = new ReduceEntriesTask<K,V>
5483	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5484	>	rights, reducer)).fork();
5485	>	}
5486	>	Map.Entry<K,V> r = null;
5487	>	for (Node<K,V> p; (p = advance()) != null; )
5488	>	r = (r == null) ? p : reducer.apply(r, p);
5489	>	result = r;
5490	>	CountedCompleter<?> c;
5491	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5492	>	@SuppressWarnings("unchecked")
5493	>	ReduceEntriesTask<K,V>
5494	>	t = (ReduceEntriesTask<K,V>)c,
5495	>	s = t.rights;
5496	>	while (s != null) {
5497	>	Map.Entry<K,V> tr, sr;
5498	>	if ((sr = s.result) != null)
5499	>	t.result = (((tr = t.result) == null) ? sr :
5500	>	reducer.apply(tr, sr));
5501	>	s = t.rights = s.nextRight;
5502		}
5503		}
5504		}
5505	<	finally {
5506	<	seg.unlock();
5505	>	}
5506	>	}
5507	>
5508	>	@SuppressWarnings("serial")
5509	>	static final class MapReduceKeysTask<K,V,U>
5510	>	extends BulkTask<K,V,U> {
5511	>	final Function<? super K, ? extends U> transformer;
5512	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5513	>	U result;
5514	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5515	>	MapReduceKeysTask
5516	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5517	>	MapReduceKeysTask<K,V,U> nextRight,
5518	>	Function<? super K, ? extends U> transformer,
5519	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5520	>	super(p, b, i, f, t); this.nextRight = nextRight;
5521	>	this.transformer = transformer;
5522	>	this.reducer = reducer;
5523	>	}
5524	>	public final U getRawResult() { return result; }
5525	>	public final void compute() {
5526	>	final Function<? super K, ? extends U> transformer;
5527	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5528	>	if ((transformer = this.transformer) != null &&
5529	>	(reducer = this.reducer) != null) {
5530	>	for (int i = baseIndex, f, h; batch > 0 &&
5531	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5532	>	addToPendingCount(1);
5533	>	(rights = new MapReduceKeysTask<K,V,U>
5534	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5535	>	rights, transformer, reducer)).fork();
5536	>	}
5537	>	U r = null;
5538	>	for (Node<K,V> p; (p = advance()) != null; ) {
5539	>	U u;
5540	>	if ((u = transformer.apply(p.key)) != null)
5541	>	r = (r == null) ? u : reducer.apply(r, u);
5542	>	}
5543	>	result = r;
5544	>	CountedCompleter<?> c;
5545	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5546	>	@SuppressWarnings("unchecked")
5547	>	MapReduceKeysTask<K,V,U>
5548	>	t = (MapReduceKeysTask<K,V,U>)c,
5549	>	s = t.rights;
5550	>	while (s != null) {
5551	>	U tr, sr;
5552	>	if ((sr = s.result) != null)
5553	>	t.result = (((tr = t.result) == null) ? sr :
5554	>	reducer.apply(tr, sr));
5555	>	s = t.rights = s.nextRight;
5556	>	}
5557	>	}
5558		}
5559		}
1023	–	s.writeObject(null);
1024	–	s.writeObject(null);
5560		}
5561
5562	<	/**
5563	<	* Reconstitute the <tt>ConcurrentHashMap</tt>
5564	<	* instance from a stream (i.e.,
5565	<	* deserialize it).
5566	<	* @param s the stream
5567	<	*/
5568	<	private void readObject(java.io.ObjectInputStream s)
5569	<	throws IOException, ClassNotFoundException  {
5570	<	s.defaultReadObject();
5562	>	@SuppressWarnings("serial")
5563	>	static final class MapReduceValuesTask<K,V,U>
5564	>	extends BulkTask<K,V,U> {
5565	>	final Function<? super V, ? extends U> transformer;
5566	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5567	>	U result;
5568	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5569	>	MapReduceValuesTask
5570	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5571	>	MapReduceValuesTask<K,V,U> nextRight,
5572	>	Function<? super V, ? extends U> transformer,
5573	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5574	>	super(p, b, i, f, t); this.nextRight = nextRight;
5575	>	this.transformer = transformer;
5576	>	this.reducer = reducer;
5577	>	}
5578	>	public final U getRawResult() { return result; }
5579	>	public final void compute() {
5580	>	final Function<? super V, ? extends U> transformer;
5581	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5582	>	if ((transformer = this.transformer) != null &&
5583	>	(reducer = this.reducer) != null) {
5584	>	for (int i = baseIndex, f, h; batch > 0 &&
5585	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5586	>	addToPendingCount(1);
5587	>	(rights = new MapReduceValuesTask<K,V,U>
5588	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5589	>	rights, transformer, reducer)).fork();
5590	>	}
5591	>	U r = null;
5592	>	for (Node<K,V> p; (p = advance()) != null; ) {
5593	>	U u;
5594	>	if ((u = transformer.apply(p.val)) != null)
5595	>	r = (r == null) ? u : reducer.apply(r, u);
5596	>	}
5597	>	result = r;
5598	>	CountedCompleter<?> c;
5599	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5600	>	@SuppressWarnings("unchecked")
5601	>	MapReduceValuesTask<K,V,U>
5602	>	t = (MapReduceValuesTask<K,V,U>)c,
5603	>	s = t.rights;
5604	>	while (s != null) {
5605	>	U tr, sr;
5606	>	if ((sr = s.result) != null)
5607	>	t.result = (((tr = t.result) == null) ? sr :
5608	>	reducer.apply(tr, sr));
5609	>	s = t.rights = s.nextRight;
5610	>	}
5611	>	}
5612	>	}
5613	>	}
5614	>	}
5615
5616	<	// Initialize each segment to be minimally sized, and let grow.
5617	<	for (int i = 0; i < segments.length; ++i) {
5618	<	segments[i].setTable(new HashEntry[1]);
5616	>	@SuppressWarnings("serial")
5617	>	static final class MapReduceEntriesTask<K,V,U>
5618	>	extends BulkTask<K,V,U> {
5619	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5620	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5621	>	U result;
5622	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5623	>	MapReduceEntriesTask
5624	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5625	>	MapReduceEntriesTask<K,V,U> nextRight,
5626	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5627	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5628	>	super(p, b, i, f, t); this.nextRight = nextRight;
5629	>	this.transformer = transformer;
5630	>	this.reducer = reducer;
5631		}
5632	+	public final U getRawResult() { return result; }
5633	+	public final void compute() {
5634	+	final Function<Map.Entry<K,V>, ? extends U> transformer;
5635	+	final BiFunction<? super U, ? super U, ? extends U> reducer;
5636	+	if ((transformer = this.transformer) != null &&
5637	+	(reducer = this.reducer) != null) {
5638	+	for (int i = baseIndex, f, h; batch > 0 &&
5639	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5640	+	addToPendingCount(1);
5641	+	(rights = new MapReduceEntriesTask<K,V,U>
5642	+	(this, batch >>>= 1, baseLimit = h, f, tab,
5643	+	rights, transformer, reducer)).fork();
5644	+	}
5645	+	U r = null;
5646	+	for (Node<K,V> p; (p = advance()) != null; ) {
5647	+	U u;
5648	+	if ((u = transformer.apply(p)) != null)
5649	+	r = (r == null) ? u : reducer.apply(r, u);
5650	+	}
5651	+	result = r;
5652	+	CountedCompleter<?> c;
5653	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5654	+	@SuppressWarnings("unchecked")
5655	+	MapReduceEntriesTask<K,V,U>
5656	+	t = (MapReduceEntriesTask<K,V,U>)c,
5657	+	s = t.rights;
5658	+	while (s != null) {
5659	+	U tr, sr;
5660	+	if ((sr = s.result) != null)
5661	+	t.result = (((tr = t.result) == null) ? sr :
5662	+	reducer.apply(tr, sr));
5663	+	s = t.rights = s.nextRight;
5664	+	}
5665	+	}
5666	+	}
5667	+	}
5668	+	}
5669
5670	<	// Read the keys and values, and put the mappings in the table
5671	<	for (;;) {
5672	<	K key = (K) s.readObject();
5673	<	V value = (V) s.readObject();
5674	<	if (key == null)
5675	<	break;
5676	<	put(key, value);
5670	>	@SuppressWarnings("serial")
5671	>	static final class MapReduceMappingsTask<K,V,U>
5672	>	extends BulkTask<K,V,U> {
5673	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5674	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5675	>	U result;
5676	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5677	>	MapReduceMappingsTask
5678	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5679	>	MapReduceMappingsTask<K,V,U> nextRight,
5680	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5681	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5682	>	super(p, b, i, f, t); this.nextRight = nextRight;
5683	>	this.transformer = transformer;
5684	>	this.reducer = reducer;
5685	>	}
5686	>	public final U getRawResult() { return result; }
5687	>	public final void compute() {
5688	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5689	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5690	>	if ((transformer = this.transformer) != null &&
5691	>	(reducer = this.reducer) != null) {
5692	>	for (int i = baseIndex, f, h; batch > 0 &&
5693	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5694	>	addToPendingCount(1);
5695	>	(rights = new MapReduceMappingsTask<K,V,U>
5696	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5697	>	rights, transformer, reducer)).fork();
5698	>	}
5699	>	U r = null;
5700	>	for (Node<K,V> p; (p = advance()) != null; ) {
5701	>	U u;
5702	>	if ((u = transformer.apply(p.key, p.val)) != null)
5703	>	r = (r == null) ? u : reducer.apply(r, u);
5704	>	}
5705	>	result = r;
5706	>	CountedCompleter<?> c;
5707	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5708	>	@SuppressWarnings("unchecked")
5709	>	MapReduceMappingsTask<K,V,U>
5710	>	t = (MapReduceMappingsTask<K,V,U>)c,
5711	>	s = t.rights;
5712	>	while (s != null) {
5713	>	U tr, sr;
5714	>	if ((sr = s.result) != null)
5715	>	t.result = (((tr = t.result) == null) ? sr :
5716	>	reducer.apply(tr, sr));
5717	>	s = t.rights = s.nextRight;
5718	>	}
5719	>	}
5720	>	}
5721	>	}
5722	>	}
5723	>
5724	>	@SuppressWarnings("serial")
5725	>	static final class MapReduceKeysToDoubleTask<K,V>
5726	>	extends BulkTask<K,V,Double> {
5727	>	final ToDoubleFunction<? super K> transformer;
5728	>	final DoubleBinaryOperator reducer;
5729	>	final double basis;
5730	>	double result;
5731	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5732	>	MapReduceKeysToDoubleTask
5733	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5734	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5735	>	ToDoubleFunction<? super K> transformer,
5736	>	double basis,
5737	>	DoubleBinaryOperator reducer) {
5738	>	super(p, b, i, f, t); this.nextRight = nextRight;
5739	>	this.transformer = transformer;
5740	>	this.basis = basis; this.reducer = reducer;
5741	>	}
5742	>	public final Double getRawResult() { return result; }
5743	>	public final void compute() {
5744	>	final ToDoubleFunction<? super K> transformer;
5745	>	final DoubleBinaryOperator reducer;
5746	>	if ((transformer = this.transformer) != null &&
5747	>	(reducer = this.reducer) != null) {
5748	>	double r = this.basis;
5749	>	for (int i = baseIndex, f, h; batch > 0 &&
5750	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5751	>	addToPendingCount(1);
5752	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5753	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5754	>	rights, transformer, r, reducer)).fork();
5755	>	}
5756	>	for (Node<K,V> p; (p = advance()) != null; )
5757	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5758	>	result = r;
5759	>	CountedCompleter<?> c;
5760	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5761	>	@SuppressWarnings("unchecked")
5762	>	MapReduceKeysToDoubleTask<K,V>
5763	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5764	>	s = t.rights;
5765	>	while (s != null) {
5766	>	t.result = reducer.applyAsDouble(t.result, s.result);
5767	>	s = t.rights = s.nextRight;
5768	>	}
5769	>	}
5770	>	}
5771		}
5772		}
1051	–	}
5773
5774	+	@SuppressWarnings("serial")
5775	+	static final class MapReduceValuesToDoubleTask<K,V>
5776	+	extends BulkTask<K,V,Double> {
5777	+	final ToDoubleFunction<? super V> transformer;
5778	+	final DoubleBinaryOperator reducer;
5779	+	final double basis;
5780	+	double result;
5781	+	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5782	+	MapReduceValuesToDoubleTask
5783	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5784	+	MapReduceValuesToDoubleTask<K,V> nextRight,
5785	+	ToDoubleFunction<? super V> transformer,
5786	+	double basis,
5787	+	DoubleBinaryOperator reducer) {
5788	+	super(p, b, i, f, t); this.nextRight = nextRight;
5789	+	this.transformer = transformer;
5790	+	this.basis = basis; this.reducer = reducer;
5791	+	}
5792	+	public final Double getRawResult() { return result; }
5793	+	public final void compute() {
5794	+	final ToDoubleFunction<? super V> transformer;
5795	+	final DoubleBinaryOperator reducer;
5796	+	if ((transformer = this.transformer) != null &&
5797	+	(reducer = this.reducer) != null) {
5798	+	double r = this.basis;
5799	+	for (int i = baseIndex, f, h; batch > 0 &&
5800	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5801	+	addToPendingCount(1);
5802	+	(rights = new MapReduceValuesToDoubleTask<K,V>
5803	+	(this, batch >>>= 1, baseLimit = h, f, tab,
5804	+	rights, transformer, r, reducer)).fork();
5805	+	}
5806	+	for (Node<K,V> p; (p = advance()) != null; )
5807	+	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5808	+	result = r;
5809	+	CountedCompleter<?> c;
5810	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5811	+	@SuppressWarnings("unchecked")
5812	+	MapReduceValuesToDoubleTask<K,V>
5813	+	t = (MapReduceValuesToDoubleTask<K,V>)c,
5814	+	s = t.rights;
5815	+	while (s != null) {
5816	+	t.result = reducer.applyAsDouble(t.result, s.result);
5817	+	s = t.rights = s.nextRight;
5818	+	}
5819	+	}
5820	+	}
5821	+	}
5822	+	}
5823	+
5824	+	@SuppressWarnings("serial")
5825	+	static final class MapReduceEntriesToDoubleTask<K,V>
5826	+	extends BulkTask<K,V,Double> {
5827	+	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5828	+	final DoubleBinaryOperator reducer;
5829	+	final double basis;
5830	+	double result;
5831	+	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5832	+	MapReduceEntriesToDoubleTask
5833	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5834	+	MapReduceEntriesToDoubleTask<K,V> nextRight,
5835	+	ToDoubleFunction<Map.Entry<K,V>> transformer,
5836	+	double basis,
5837	+	DoubleBinaryOperator reducer) {
5838	+	super(p, b, i, f, t); this.nextRight = nextRight;
5839	+	this.transformer = transformer;
5840	+	this.basis = basis; this.reducer = reducer;
5841	+	}
5842	+	public final Double getRawResult() { return result; }
5843	+	public final void compute() {
5844	+	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5845	+	final DoubleBinaryOperator reducer;
5846	+	if ((transformer = this.transformer) != null &&
5847	+	(reducer = this.reducer) != null) {
5848	+	double r = this.basis;
5849	+	for (int i = baseIndex, f, h; batch > 0 &&
5850	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5851	+	addToPendingCount(1);
5852	+	(rights = new MapReduceEntriesToDoubleTask<K,V>
5853	+	(this, batch >>>= 1, baseLimit = h, f, tab,
5854	+	rights, transformer, r, reducer)).fork();
5855	+	}
5856	+	for (Node<K,V> p; (p = advance()) != null; )
5857	+	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5858	+	result = r;
5859	+	CountedCompleter<?> c;
5860	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5861	+	@SuppressWarnings("unchecked")
5862	+	MapReduceEntriesToDoubleTask<K,V>
5863	+	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5864	+	s = t.rights;
5865	+	while (s != null) {
5866	+	t.result = reducer.applyAsDouble(t.result, s.result);
5867	+	s = t.rights = s.nextRight;
5868	+	}
5869	+	}
5870	+	}
5871	+	}
5872	+	}
5873	+
5874	+	@SuppressWarnings("serial")
5875	+	static final class MapReduceMappingsToDoubleTask<K,V>
5876	+	extends BulkTask<K,V,Double> {
5877	+	final ToDoubleBiFunction<? super K, ? super V> transformer;
5878	+	final DoubleBinaryOperator reducer;
5879	+	final double basis;
5880	+	double result;
5881	+	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5882	+	MapReduceMappingsToDoubleTask
5883	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5884	+	MapReduceMappingsToDoubleTask<K,V> nextRight,
5885	+	ToDoubleBiFunction<? super K, ? super V> transformer,
5886	+	double basis,
5887	+	DoubleBinaryOperator reducer) {
5888	+	super(p, b, i, f, t); this.nextRight = nextRight;
5889	+	this.transformer = transformer;
5890	+	this.basis = basis; this.reducer = reducer;
5891	+	}
5892	+	public final Double getRawResult() { return result; }
5893	+	public final void compute() {
5894	+	final ToDoubleBiFunction<? super K, ? super V> transformer;
5895	+	final DoubleBinaryOperator reducer;
5896	+	if ((transformer = this.transformer) != null &&
5897	+	(reducer = this.reducer) != null) {
5898	+	double r = this.basis;
5899	+	for (int i = baseIndex, f, h; batch > 0 &&
5900	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5901	+	addToPendingCount(1);
5902	+	(rights = new MapReduceMappingsToDoubleTask<K,V>
5903	+	(this, batch >>>= 1, baseLimit = h, f, tab,
5904	+	rights, transformer, r, reducer)).fork();
5905	+	}
5906	+	for (Node<K,V> p; (p = advance()) != null; )
5907	+	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5908	+	result = r;
5909	+	CountedCompleter<?> c;
5910	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5911	+	@SuppressWarnings("unchecked")
5912	+	MapReduceMappingsToDoubleTask<K,V>
5913	+	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5914	+	s = t.rights;
5915	+	while (s != null) {
5916	+	t.result = reducer.applyAsDouble(t.result, s.result);
5917	+	s = t.rights = s.nextRight;
5918	+	}
5919	+	}
5920	+	}
5921	+	}
5922	+	}
5923	+
5924	+	@SuppressWarnings("serial")
5925	+	static final class MapReduceKeysToLongTask<K,V>
5926	+	extends BulkTask<K,V,Long> {
5927	+	final ToLongFunction<? super K> transformer;
5928	+	final LongBinaryOperator reducer;
5929	+	final long basis;
5930	+	long result;
5931	+	MapReduceKeysToLongTask<K,V> rights, nextRight;
5932	+	MapReduceKeysToLongTask
5933	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5934	+	MapReduceKeysToLongTask<K,V> nextRight,
5935	+	ToLongFunction<? super K> transformer,
5936	+	long basis,
5937	+	LongBinaryOperator reducer) {
5938	+	super(p, b, i, f, t); this.nextRight = nextRight;
5939	+	this.transformer = transformer;
5940	+	this.basis = basis; this.reducer = reducer;
5941	+	}
5942	+	public final Long getRawResult() { return result; }
5943	+	public final void compute() {
5944	+	final ToLongFunction<? super K> transformer;
5945	+	final LongBinaryOperator reducer;
5946	+	if ((transformer = this.transformer) != null &&
5947	+	(reducer = this.reducer) != null) {
5948	+	long r = this.basis;
5949	+	for (int i = baseIndex, f, h; batch > 0 &&
5950	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5951	+	addToPendingCount(1);
5952	+	(rights = new MapReduceKeysToLongTask<K,V>
5953	+	(this, batch >>>= 1, baseLimit = h, f, tab,
5954	+	rights, transformer, r, reducer)).fork();
5955	+	}
5956	+	for (Node<K,V> p; (p = advance()) != null; )
5957	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5958	+	result = r;
5959	+	CountedCompleter<?> c;
5960	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5961	+	@SuppressWarnings("unchecked")
5962	+	MapReduceKeysToLongTask<K,V>
5963	+	t = (MapReduceKeysToLongTask<K,V>)c,
5964	+	s = t.rights;
5965	+	while (s != null) {
5966	+	t.result = reducer.applyAsLong(t.result, s.result);
5967	+	s = t.rights = s.nextRight;
5968	+	}
5969	+	}
5970	+	}
5971	+	}
5972	+	}
5973	+
5974	+	@SuppressWarnings("serial")
5975	+	static final class MapReduceValuesToLongTask<K,V>
5976	+	extends BulkTask<K,V,Long> {
5977	+	final ToLongFunction<? super V> transformer;
5978	+	final LongBinaryOperator reducer;
5979	+	final long basis;
5980	+	long result;
5981	+	MapReduceValuesToLongTask<K,V> rights, nextRight;
5982	+	MapReduceValuesToLongTask
5983	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5984	+	MapReduceValuesToLongTask<K,V> nextRight,
5985	+	ToLongFunction<? super V> transformer,
5986	+	long basis,
5987	+	LongBinaryOperator reducer) {
5988	+	super(p, b, i, f, t); this.nextRight = nextRight;
5989	+	this.transformer = transformer;
5990	+	this.basis = basis; this.reducer = reducer;
5991	+	}
5992	+	public final Long getRawResult() { return result; }
5993	+	public final void compute() {
5994	+	final ToLongFunction<? super V> transformer;
5995	+	final LongBinaryOperator reducer;
5996	+	if ((transformer = this.transformer) != null &&
5997	+	(reducer = this.reducer) != null) {
5998	+	long r = this.basis;
5999	+	for (int i = baseIndex, f, h; batch > 0 &&
6000	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6001	+	addToPendingCount(1);
6002	+	(rights = new MapReduceValuesToLongTask<K,V>
6003	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6004	+	rights, transformer, r, reducer)).fork();
6005	+	}
6006	+	for (Node<K,V> p; (p = advance()) != null; )
6007	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
6008	+	result = r;
6009	+	CountedCompleter<?> c;
6010	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6011	+	@SuppressWarnings("unchecked")
6012	+	MapReduceValuesToLongTask<K,V>
6013	+	t = (MapReduceValuesToLongTask<K,V>)c,
6014	+	s = t.rights;
6015	+	while (s != null) {
6016	+	t.result = reducer.applyAsLong(t.result, s.result);
6017	+	s = t.rights = s.nextRight;
6018	+	}
6019	+	}
6020	+	}
6021	+	}
6022	+	}
6023	+
6024	+	@SuppressWarnings("serial")
6025	+	static final class MapReduceEntriesToLongTask<K,V>
6026	+	extends BulkTask<K,V,Long> {
6027	+	final ToLongFunction<Map.Entry<K,V>> transformer;
6028	+	final LongBinaryOperator reducer;
6029	+	final long basis;
6030	+	long result;
6031	+	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6032	+	MapReduceEntriesToLongTask
6033	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6034	+	MapReduceEntriesToLongTask<K,V> nextRight,
6035	+	ToLongFunction<Map.Entry<K,V>> transformer,
6036	+	long basis,
6037	+	LongBinaryOperator reducer) {
6038	+	super(p, b, i, f, t); this.nextRight = nextRight;
6039	+	this.transformer = transformer;
6040	+	this.basis = basis; this.reducer = reducer;
6041	+	}
6042	+	public final Long getRawResult() { return result; }
6043	+	public final void compute() {
6044	+	final ToLongFunction<Map.Entry<K,V>> transformer;
6045	+	final LongBinaryOperator reducer;
6046	+	if ((transformer = this.transformer) != null &&
6047	+	(reducer = this.reducer) != null) {
6048	+	long r = this.basis;
6049	+	for (int i = baseIndex, f, h; batch > 0 &&
6050	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6051	+	addToPendingCount(1);
6052	+	(rights = new MapReduceEntriesToLongTask<K,V>
6053	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6054	+	rights, transformer, r, reducer)).fork();
6055	+	}
6056	+	for (Node<K,V> p; (p = advance()) != null; )
6057	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
6058	+	result = r;
6059	+	CountedCompleter<?> c;
6060	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6061	+	@SuppressWarnings("unchecked")
6062	+	MapReduceEntriesToLongTask<K,V>
6063	+	t = (MapReduceEntriesToLongTask<K,V>)c,
6064	+	s = t.rights;
6065	+	while (s != null) {
6066	+	t.result = reducer.applyAsLong(t.result, s.result);
6067	+	s = t.rights = s.nextRight;
6068	+	}
6069	+	}
6070	+	}
6071	+	}
6072	+	}
6073	+
6074	+	@SuppressWarnings("serial")
6075	+	static final class MapReduceMappingsToLongTask<K,V>
6076	+	extends BulkTask<K,V,Long> {
6077	+	final ToLongBiFunction<? super K, ? super V> transformer;
6078	+	final LongBinaryOperator reducer;
6079	+	final long basis;
6080	+	long result;
6081	+	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6082	+	MapReduceMappingsToLongTask
6083	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6084	+	MapReduceMappingsToLongTask<K,V> nextRight,
6085	+	ToLongBiFunction<? super K, ? super V> transformer,
6086	+	long basis,
6087	+	LongBinaryOperator reducer) {
6088	+	super(p, b, i, f, t); this.nextRight = nextRight;
6089	+	this.transformer = transformer;
6090	+	this.basis = basis; this.reducer = reducer;
6091	+	}
6092	+	public final Long getRawResult() { return result; }
6093	+	public final void compute() {
6094	+	final ToLongBiFunction<? super K, ? super V> transformer;
6095	+	final LongBinaryOperator reducer;
6096	+	if ((transformer = this.transformer) != null &&
6097	+	(reducer = this.reducer) != null) {
6098	+	long r = this.basis;
6099	+	for (int i = baseIndex, f, h; batch > 0 &&
6100	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6101	+	addToPendingCount(1);
6102	+	(rights = new MapReduceMappingsToLongTask<K,V>
6103	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6104	+	rights, transformer, r, reducer)).fork();
6105	+	}
6106	+	for (Node<K,V> p; (p = advance()) != null; )
6107	+	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
6108	+	result = r;
6109	+	CountedCompleter<?> c;
6110	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6111	+	@SuppressWarnings("unchecked")
6112	+	MapReduceMappingsToLongTask<K,V>
6113	+	t = (MapReduceMappingsToLongTask<K,V>)c,
6114	+	s = t.rights;
6115	+	while (s != null) {
6116	+	t.result = reducer.applyAsLong(t.result, s.result);
6117	+	s = t.rights = s.nextRight;
6118	+	}
6119	+	}
6120	+	}
6121	+	}
6122	+	}
6123	+
6124	+	@SuppressWarnings("serial")
6125	+	static final class MapReduceKeysToIntTask<K,V>
6126	+	extends BulkTask<K,V,Integer> {
6127	+	final ToIntFunction<? super K> transformer;
6128	+	final IntBinaryOperator reducer;
6129	+	final int basis;
6130	+	int result;
6131	+	MapReduceKeysToIntTask<K,V> rights, nextRight;
6132	+	MapReduceKeysToIntTask
6133	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6134	+	MapReduceKeysToIntTask<K,V> nextRight,
6135	+	ToIntFunction<? super K> transformer,
6136	+	int basis,
6137	+	IntBinaryOperator reducer) {
6138	+	super(p, b, i, f, t); this.nextRight = nextRight;
6139	+	this.transformer = transformer;
6140	+	this.basis = basis; this.reducer = reducer;
6141	+	}
6142	+	public final Integer getRawResult() { return result; }
6143	+	public final void compute() {
6144	+	final ToIntFunction<? super K> transformer;
6145	+	final IntBinaryOperator reducer;
6146	+	if ((transformer = this.transformer) != null &&
6147	+	(reducer = this.reducer) != null) {
6148	+	int r = this.basis;
6149	+	for (int i = baseIndex, f, h; batch > 0 &&
6150	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6151	+	addToPendingCount(1);
6152	+	(rights = new MapReduceKeysToIntTask<K,V>
6153	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6154	+	rights, transformer, r, reducer)).fork();
6155	+	}
6156	+	for (Node<K,V> p; (p = advance()) != null; )
6157	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6158	+	result = r;
6159	+	CountedCompleter<?> c;
6160	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6161	+	@SuppressWarnings("unchecked")
6162	+	MapReduceKeysToIntTask<K,V>
6163	+	t = (MapReduceKeysToIntTask<K,V>)c,
6164	+	s = t.rights;
6165	+	while (s != null) {
6166	+	t.result = reducer.applyAsInt(t.result, s.result);
6167	+	s = t.rights = s.nextRight;
6168	+	}
6169	+	}
6170	+	}
6171	+	}
6172	+	}
6173	+
6174	+	@SuppressWarnings("serial")
6175	+	static final class MapReduceValuesToIntTask<K,V>
6176	+	extends BulkTask<K,V,Integer> {
6177	+	final ToIntFunction<? super V> transformer;
6178	+	final IntBinaryOperator reducer;
6179	+	final int basis;
6180	+	int result;
6181	+	MapReduceValuesToIntTask<K,V> rights, nextRight;
6182	+	MapReduceValuesToIntTask
6183	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6184	+	MapReduceValuesToIntTask<K,V> nextRight,
6185	+	ToIntFunction<? super V> transformer,
6186	+	int basis,
6187	+	IntBinaryOperator reducer) {
6188	+	super(p, b, i, f, t); this.nextRight = nextRight;
6189	+	this.transformer = transformer;
6190	+	this.basis = basis; this.reducer = reducer;
6191	+	}
6192	+	public final Integer getRawResult() { return result; }
6193	+	public final void compute() {
6194	+	final ToIntFunction<? super V> transformer;
6195	+	final IntBinaryOperator reducer;
6196	+	if ((transformer = this.transformer) != null &&
6197	+	(reducer = this.reducer) != null) {
6198	+	int r = this.basis;
6199	+	for (int i = baseIndex, f, h; batch > 0 &&
6200	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6201	+	addToPendingCount(1);
6202	+	(rights = new MapReduceValuesToIntTask<K,V>
6203	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6204	+	rights, transformer, r, reducer)).fork();
6205	+	}
6206	+	for (Node<K,V> p; (p = advance()) != null; )
6207	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6208	+	result = r;
6209	+	CountedCompleter<?> c;
6210	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6211	+	@SuppressWarnings("unchecked")
6212	+	MapReduceValuesToIntTask<K,V>
6213	+	t = (MapReduceValuesToIntTask<K,V>)c,
6214	+	s = t.rights;
6215	+	while (s != null) {
6216	+	t.result = reducer.applyAsInt(t.result, s.result);
6217	+	s = t.rights = s.nextRight;
6218	+	}
6219	+	}
6220	+	}
6221	+	}
6222	+	}
6223	+
6224	+	@SuppressWarnings("serial")
6225	+	static final class MapReduceEntriesToIntTask<K,V>
6226	+	extends BulkTask<K,V,Integer> {
6227	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6228	+	final IntBinaryOperator reducer;
6229	+	final int basis;
6230	+	int result;
6231	+	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6232	+	MapReduceEntriesToIntTask
6233	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6234	+	MapReduceEntriesToIntTask<K,V> nextRight,
6235	+	ToIntFunction<Map.Entry<K,V>> transformer,
6236	+	int basis,
6237	+	IntBinaryOperator reducer) {
6238	+	super(p, b, i, f, t); this.nextRight = nextRight;
6239	+	this.transformer = transformer;
6240	+	this.basis = basis; this.reducer = reducer;
6241	+	}
6242	+	public final Integer getRawResult() { return result; }
6243	+	public final void compute() {
6244	+	final ToIntFunction<Map.Entry<K,V>> transformer;
6245	+	final IntBinaryOperator reducer;
6246	+	if ((transformer = this.transformer) != null &&
6247	+	(reducer = this.reducer) != null) {
6248	+	int r = this.basis;
6249	+	for (int i = baseIndex, f, h; batch > 0 &&
6250	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6251	+	addToPendingCount(1);
6252	+	(rights = new MapReduceEntriesToIntTask<K,V>
6253	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6254	+	rights, transformer, r, reducer)).fork();
6255	+	}
6256	+	for (Node<K,V> p; (p = advance()) != null; )
6257	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6258	+	result = r;
6259	+	CountedCompleter<?> c;
6260	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6261	+	@SuppressWarnings("unchecked")
6262	+	MapReduceEntriesToIntTask<K,V>
6263	+	t = (MapReduceEntriesToIntTask<K,V>)c,
6264	+	s = t.rights;
6265	+	while (s != null) {
6266	+	t.result = reducer.applyAsInt(t.result, s.result);
6267	+	s = t.rights = s.nextRight;
6268	+	}
6269	+	}
6270	+	}
6271	+	}
6272	+	}
6273	+
6274	+	@SuppressWarnings("serial")
6275	+	static final class MapReduceMappingsToIntTask<K,V>
6276	+	extends BulkTask<K,V,Integer> {
6277	+	final ToIntBiFunction<? super K, ? super V> transformer;
6278	+	final IntBinaryOperator reducer;
6279	+	final int basis;
6280	+	int result;
6281	+	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6282	+	MapReduceMappingsToIntTask
6283	+	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6284	+	MapReduceMappingsToIntTask<K,V> nextRight,
6285	+	ToIntBiFunction<? super K, ? super V> transformer,
6286	+	int basis,
6287	+	IntBinaryOperator reducer) {
6288	+	super(p, b, i, f, t); this.nextRight = nextRight;
6289	+	this.transformer = transformer;
6290	+	this.basis = basis; this.reducer = reducer;
6291	+	}
6292	+	public final Integer getRawResult() { return result; }
6293	+	public final void compute() {
6294	+	final ToIntBiFunction<? super K, ? super V> transformer;
6295	+	final IntBinaryOperator reducer;
6296	+	if ((transformer = this.transformer) != null &&
6297	+	(reducer = this.reducer) != null) {
6298	+	int r = this.basis;
6299	+	for (int i = baseIndex, f, h; batch > 0 &&
6300	+	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6301	+	addToPendingCount(1);
6302	+	(rights = new MapReduceMappingsToIntTask<K,V>
6303	+	(this, batch >>>= 1, baseLimit = h, f, tab,
6304	+	rights, transformer, r, reducer)).fork();
6305	+	}
6306	+	for (Node<K,V> p; (p = advance()) != null; )
6307	+	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6308	+	result = r;
6309	+	CountedCompleter<?> c;
6310	+	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6311	+	@SuppressWarnings("unchecked")
6312	+	MapReduceMappingsToIntTask<K,V>
6313	+	t = (MapReduceMappingsToIntTask<K,V>)c,
6314	+	s = t.rights;
6315	+	while (s != null) {
6316	+	t.result = reducer.applyAsInt(t.result, s.result);
6317	+	s = t.rights = s.nextRight;
6318	+	}
6319	+	}
6320	+	}
6321	+	}
6322	+	}
6323	+
6324	+	// Unsafe mechanics
6325	+	private static final Unsafe U = Unsafe.getUnsafe();
6326	+	private static final long SIZECTL;
6327	+	private static final long TRANSFERINDEX;
6328	+	private static final long BASECOUNT;
6329	+	private static final long CELLSBUSY;
6330	+	private static final long CELLVALUE;
6331	+	private static final int ABASE;
6332	+	private static final int ASHIFT;
6333	+
6334	+	static {
6335	+	try {
6336	+	SIZECTL = U.objectFieldOffset
6337	+	(ConcurrentHashMap.class.getDeclaredField("sizeCtl"));
6338	+	TRANSFERINDEX = U.objectFieldOffset
6339	+	(ConcurrentHashMap.class.getDeclaredField("transferIndex"));
6340	+	BASECOUNT = U.objectFieldOffset
6341	+	(ConcurrentHashMap.class.getDeclaredField("baseCount"));
6342	+	CELLSBUSY = U.objectFieldOffset
6343	+	(ConcurrentHashMap.class.getDeclaredField("cellsBusy"));
6344	+
6345	+	CELLVALUE = U.objectFieldOffset
6346	+	(CounterCell.class.getDeclaredField("value"));
6347	+
6348	+	ABASE = U.arrayBaseOffset(Node[].class);
6349	+	int scale = U.arrayIndexScale(Node[].class);
6350	+	if ((scale & (scale - 1)) != 0)
6351	+	throw new ExceptionInInitializerError("array index scale not a power of two");
6352	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6353	+	} catch (ReflectiveOperationException e) {
6354	+	throw new ExceptionInInitializerError(e);
6355	+	}
6356	+
6357	+	// Reduce the risk of rare disastrous classloading in first call to
6358	+	// LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
6359	+	Class<?> ensureLoaded = LockSupport.class;
6360	+
6361	+	// Eager class load observed to help JIT during startup
6362	+	ensureLoaded = ReservationNode.class;
6363	+	}
6364	+	}

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines