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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.115 by jsr166, Fri Dec 2 14:28:17 2011 UTC vs.
Revision 1.160 by dl, Thu Jan 10 15:03:25 2013 UTC

#	Line 5 | Line 5
5		*/
6
7		package java.util.concurrent;
8	<	import java.util.concurrent.locks.*;
9	<	import java.util.*;
8	>	import java.util.concurrent.ForkJoinPool;
9	>	import java.util.concurrent.CountedCompleter;
10	>	import java.util.function.*;
11	>	import java.util.stream.Spliterator;
12	>	import java.util.stream.Stream;
13	>	import java.util.stream.Streams;
14	>
15	>	import java.util.Comparator;
16	>	import java.util.Arrays;
17	>	import java.util.Map;
18	>	import java.util.Set;
19	>	import java.util.Collection;
20	>	import java.util.AbstractMap;
21	>	import java.util.AbstractSet;
22	>	import java.util.AbstractCollection;
23	>	import java.util.Hashtable;
24	>	import java.util.HashMap;
25	>	import java.util.Iterator;
26	>	import java.util.Enumeration;
27	>	import java.util.ConcurrentModificationException;
28	>	import java.util.NoSuchElementException;
29	>	import java.util.concurrent.ConcurrentMap;
30	>	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
31	>	import java.util.concurrent.atomic.AtomicInteger;
32	>	import java.util.concurrent.atomic.AtomicReference;
33		import java.io.Serializable;
34
35		/**
36		* A hash table supporting full concurrency of retrievals and
37	<	* adjustable expected concurrency for updates. This class obeys the
37	>	* high expected concurrency for updates. This class obeys the
38		* same functional specification as {@link java.util.Hashtable}, and
39		* includes versions of methods corresponding to each method of
40	<	* <tt>Hashtable</tt>. However, even though all operations are
40	>	* {@code Hashtable}. However, even though all operations are
41		* thread-safe, retrieval operations do <em>not</em> entail locking,
42		* and there is <em>not</em> any support for locking the entire table
43		* in a way that prevents all access.  This class is fully
44	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
44	>	* interoperable with {@code Hashtable} in programs that rely on its
45		* thread safety but not on its synchronization details.
46		*
47	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
48	<	* block, so may overlap with update operations (including
49	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
50	<	* of the most recently <em>completed</em> update operations holding
51	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
52	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
53	<	* removal of only some entries.  Similarly, Iterators and
54	<	* Enumerations return elements reflecting the state of the hash table
55	<	* at some point at or since the creation of the iterator/enumeration.
56	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
57	<	* However, iterators are designed to be used by only one thread at a time.
58	<	*
59	<	* <p> The allowed concurrency among update operations is guided by
60	<	* the optional <tt>concurrencyLevel</tt> constructor argument
61	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
62	<	* table is internally partitioned to try to permit the indicated
63	<	* number of concurrent updates without contention. Because placement
64	<	* in hash tables is essentially random, the actual concurrency will
65	<	* vary.  Ideally, you should choose a value to accommodate as many
66	<	* threads as will ever concurrently modify the table. Using a
67	<	* significantly higher value than you need can waste space and time,
68	<	* and a significantly lower value can lead to thread contention. But
69	<	* overestimates and underestimates within an order of magnitude do
70	<	* not usually have much noticeable impact. A value of one is
71	<	* appropriate when it is known that only one thread will modify and
72	<	* all others will only read. Also, resizing this or any other kind of
73	<	* hash table is a relatively slow operation, so, when possible, it is
74	<	* a good idea to provide estimates of expected table sizes in
75	<	* constructors.
47	>	* <p>Retrieval operations (including {@code get}) generally do not
48	>	* block, so may overlap with update operations (including {@code put}
49	>	* and {@code remove}). Retrievals reflect the results of the most
50	>	* recently <em>completed</em> update operations holding upon their
51	>	* onset. (More formally, an update operation for a given key bears a
52	>	* <em>happens-before</em> relation with any (non-null) retrieval for
53	>	* that key reporting the updated value.)  For aggregate operations
54	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
55	>	* reflect insertion or removal of only some entries.  Similarly,
56	>	* Iterators and Enumerations return elements reflecting the state of
57	>	* the hash table at some point at or since the creation of the
58	>	* iterator/enumeration.  They do <em>not</em> throw {@link
59	>	* ConcurrentModificationException}.  However, iterators are designed
60	>	* to be used by only one thread at a time.  Bear in mind that the
61	>	* results of aggregate status methods including {@code size}, {@code
62	>	* isEmpty}, and {@code containsValue} are typically useful only when
63	>	* a map is not undergoing concurrent updates in other threads.
64	>	* Otherwise the results of these methods reflect transient states
65	>	* that may be adequate for monitoring or estimation purposes, but not
66	>	* for program control.
67	>	*
68	>	* <p>The table is dynamically expanded when there are too many
69	>	* collisions (i.e., keys that have distinct hash codes but fall into
70	>	* the same slot modulo the table size), with the expected average
71	>	* effect of maintaining roughly two bins per mapping (corresponding
72	>	* to a 0.75 load factor threshold for resizing). There may be much
73	>	* variance around this average as mappings are added and removed, but
74	>	* overall, this maintains a commonly accepted time/space tradeoff for
75	>	* hash tables.  However, resizing this or any other kind of hash
76	>	* table may be a relatively slow operation. When possible, it is a
77	>	* good idea to provide a size estimate as an optional {@code
78	>	* initialCapacity} constructor argument. An additional optional
79	>	* {@code loadFactor} constructor argument provides a further means of
80	>	* customizing initial table capacity by specifying the table density
81	>	* to be used in calculating the amount of space to allocate for the
82	>	* given number of elements.  Also, for compatibility with previous
83	>	* versions of this class, constructors may optionally specify an
84	>	* expected {@code concurrencyLevel} as an additional hint for
85	>	* internal sizing.  Note that using many keys with exactly the same
86	>	* {@code hashCode()} is a sure way to slow down performance of any
87	>	* hash table.
88	>	*
89	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
90	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
91	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
92	>	* mapped values are (perhaps transiently) not used or all take the
93	>	* same mapping value.
94	>	*
95	>	* <p>A ConcurrentHashMap can be used as scalable frequency map (a
96	>	* form of histogram or multiset) by using {@link
97	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
98	>	* {@link #computeIfAbsent}. For example, to add a count to a {@code
99	>	* ConcurrentHashMap<String,LongAdder> freqs}, you can use {@code
100	>	* freqs.computeIfAbsent(k -> new LongAdder()).increment();}
101		*
102		* <p>This class and its views and iterators implement all of the
103		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
104		* interfaces.
105		*
106	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
107	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
106	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
107	>	* does <em>not</em> allow {@code null} to be used as a key or value.
108	>	*
109	>	* <p>ConcurrentHashMaps support sequential and parallel operations
110	>	* bulk operations. (Parallel forms use the {@link
111	>	* ForkJoinPool#commonPool()}). Tasks that may be used in other
112	>	* contexts are available in class {@link ForkJoinTasks}. These
113	>	* operations are designed to be safely, and often sensibly, applied
114	>	* even with maps that are being concurrently updated by other
115	>	* threads; for example, when computing a snapshot summary of the
116	>	* values in a shared registry.  There are three kinds of operation,
117	>	* each with four forms, accepting functions with Keys, Values,
118	>	* Entries, and (Key, Value) arguments and/or return values. Because
119	>	* the elements of a ConcurrentHashMap are not ordered in any
120	>	* particular way, and may be processed in different orders in
121	>	* different parallel executions, the correctness of supplied
122	>	* functions should not depend on any ordering, or on any other
123	>	* objects or values that may transiently change while computation is
124	>	* in progress; and except for forEach actions, should ideally be
125	>	* side-effect-free.
126	>	*
127	>	* <ul>
128	>	* <li> forEach: Perform a given action on each element.
129	>	* A variant form applies a given transformation on each element
130	>	* before performing the action.</li>
131	>	*
132	>	* <li> search: Return the first available non-null result of
133	>	* applying a given function on each element; skipping further
134	>	* search when a result is found.</li>
135	>	*
136	>	* <li> reduce: Accumulate each element.  The supplied reduction
137	>	* function cannot rely on ordering (more formally, it should be
138	>	* both associative and commutative).  There are five variants:
139	>	*
140	>	* <ul>
141	>	*
142	>	* <li> Plain reductions. (There is not a form of this method for
143	>	* (key, value) function arguments since there is no corresponding
144	>	* return type.)</li>
145	>	*
146	>	* <li> Mapped reductions that accumulate the results of a given
147	>	* function applied to each element.</li>
148	>	*
149	>	* <li> Reductions to scalar doubles, longs, and ints, using a
150	>	* given basis value.</li>
151	>	*
152	>	* </li>
153	>	* </ul>
154	>	* </ul>
155	>	*
156	>	* <p>The concurrency properties of bulk operations follow
157	>	* from those of ConcurrentHashMap: Any non-null result returned
158	>	* from {@code get(key)} and related access methods bears a
159	>	* happens-before relation with the associated insertion or
160	>	* update.  The result of any bulk operation reflects the
161	>	* composition of these per-element relations (but is not
162	>	* necessarily atomic with respect to the map as a whole unless it
163	>	* is somehow known to be quiescent).  Conversely, because keys
164	>	* and values in the map are never null, null serves as a reliable
165	>	* atomic indicator of the current lack of any result.  To
166	>	* maintain this property, null serves as an implicit basis for
167	>	* all non-scalar reduction operations. For the double, long, and
168	>	* int versions, the basis should be one that, when combined with
169	>	* any other value, returns that other value (more formally, it
170	>	* should be the identity element for the reduction). Most common
171	>	* reductions have these properties; for example, computing a sum
172	>	* with basis 0 or a minimum with basis MAX_VALUE.
173	>	*
174	>	* <p>Search and transformation functions provided as arguments
175	>	* should similarly return null to indicate the lack of any result
176	>	* (in which case it is not used). In the case of mapped
177	>	* reductions, this also enables transformations to serve as
178	>	* filters, returning null (or, in the case of primitive
179	>	* specializations, the identity basis) if the element should not
180	>	* be combined. You can create compound transformations and
181	>	* filterings by composing them yourself under this "null means
182	>	* there is nothing there now" rule before using them in search or
183	>	* reduce operations.
184	>	*
185	>	* <p>Methods accepting and/or returning Entry arguments maintain
186	>	* key-value associations. They may be useful for example when
187	>	* finding the key for the greatest value. Note that "plain" Entry
188	>	* arguments can be supplied using {@code new
189	>	* AbstractMap.SimpleEntry(k,v)}.
190	>	*
191	>	* <p>Bulk operations may complete abruptly, throwing an
192	>	* exception encountered in the application of a supplied
193	>	* function. Bear in mind when handling such exceptions that other
194	>	* concurrently executing functions could also have thrown
195	>	* exceptions, or would have done so if the first exception had
196	>	* not occurred.
197	>	*
198	>	* <p>Speedups for parallel compared to sequential forms are common
199	>	* but not guaranteed.  Parallel operations involving brief functions
200	>	* on small maps may execute more slowly than sequential forms if the
201	>	* underlying work to parallelize the computation is more expensive
202	>	* than the computation itself.  Similarly, parallelization may not
203	>	* lead to much actual parallelism if all processors are busy
204	>	* performing unrelated tasks.
205	>	*
206	>	* <p>All arguments to all task methods must be non-null.
207		*
208		* <p>This class is a member of the
209		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
#	Line 67 | Line 214 | import java.io.Serializable;
214		* @param <K> the type of keys maintained by this map
215		* @param <V> the type of mapped values
216		*/
217	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
218	<	implements ConcurrentMap<K, V>, Serializable {
217	>	public class ConcurrentHashMap<K, V>
218	>	implements ConcurrentMap<K, V>, Serializable {
219		private static final long serialVersionUID = 7249069246763182397L;
220
221		/*
222	<	* The basic strategy is to subdivide the table among Segments,
223	<	* each of which itself is a concurrently readable hash table.  To
224	<	* reduce footprint, all but one segments are constructed only
225	<	* when first needed (see ensureSegment). To maintain visibility
226	<	* in the presence of lazy construction, accesses to segments as
227	<	* well as elements of segment's table must use volatile access,
228	<	* which is done via Unsafe within methods segmentAt etc
229	<	* below. These provide the functionality of AtomicReferenceArrays
230	<	* but reduce the levels of indirection. Additionally,
231	<	* volatile-writes of table elements and entry "next" fields
232	<	* within locked operations use the cheaper "lazySet" forms of
233	<	* writes (via putOrderedObject) because these writes are always
234	<	* followed by lock releases that maintain sequential consistency
235	<	* of table updates.
236	<	*
237	<	* Historical note: The previous version of this class relied
238	<	* heavily on "final" fields, which avoided some volatile reads at
239	<	* the expense of a large initial footprint.  Some remnants of
240	<	* that design (including forced construction of segment 0) exist
241	<	* to ensure serialization compatibility.
222	>	* Overview:
223	>	*
224	>	* The primary design goal of this hash table is to maintain
225	>	* concurrent readability (typically method get(), but also
226	>	* iterators and related methods) while minimizing update
227	>	* contention. Secondary goals are to keep space consumption about
228	>	* the same or better than java.util.HashMap, and to support high
229	>	* initial insertion rates on an empty table by many threads.
230	>	*
231	>	* Each key-value mapping is held in a Node.  Because Node key
232	>	* fields can contain special values, they are defined using plain
233	>	* Object types (not type "K"). This leads to a lot of explicit
234	>	* casting (and many explicit warning suppressions to tell
235	>	* compilers not to complain about it). It also allows some of the
236	>	* public methods to be factored into a smaller number of internal
237	>	* methods (although sadly not so for the five variants of
238	>	* put-related operations). The validation-based approach
239	>	* explained below leads to a lot of code sprawl because
240	>	* retry-control precludes factoring into smaller methods.
241	>	*
242	>	* The table is lazily initialized to a power-of-two size upon the
243	>	* first insertion.  Each bin in the table normally contains a
244	>	* list of Nodes (most often, the list has only zero or one Node).
245	>	* Table accesses require volatile/atomic reads, writes, and
246	>	* CASes.  Because there is no other way to arrange this without
247	>	* adding further indirections, we use intrinsics
248	>	* (sun.misc.Unsafe) operations.  The lists of nodes within bins
249	>	* are always accurately traversable under volatile reads, so long
250	>	* as lookups check hash code and non-nullness of value before
251	>	* checking key equality.
252	>	*
253	>	* We use the top (sign) bit of Node hash fields for control
254	>	* purposes -- it is available anyway because of addressing
255	>	* constraints.  Nodes with negative hash fields are forwarding
256	>	* nodes to either TreeBins or resized tables.  The lower 31 bits
257	>	* of each normal Node's hash field contain a transformation of
258	>	* the key's hash code.
259	>	*
260	>	* Insertion (via put or its variants) of the first node in an
261	>	* empty bin is performed by just CASing it to the bin.  This is
262	>	* by far the most common case for put operations under most
263	>	* key/hash distributions.  Other update operations (insert,
264	>	* delete, and replace) require locks.  We do not want to waste
265	>	* the space required to associate a distinct lock object with
266	>	* each bin, so instead use the first node of a bin list itself as
267	>	* a lock. Locking support for these locks relies on builtin
268	>	* "synchronized" monitors.
269	>	*
270	>	* Using the first node of a list as a lock does not by itself
271	>	* suffice though: When a node is locked, any update must first
272	>	* validate that it is still the first node after locking it, and
273	>	* retry if not. Because new nodes are always appended to lists,
274	>	* once a node is first in a bin, it remains first until deleted
275	>	* or the bin becomes invalidated (upon resizing).  However,
276	>	* operations that only conditionally update may inspect nodes
277	>	* until the point of update. This is a converse of sorts to the
278	>	* lazy locking technique described by Herlihy & Shavit.
279	>	*
280	>	* The main disadvantage of per-bin locks is that other update
281	>	* operations on other nodes in a bin list protected by the same
282	>	* lock can stall, for example when user equals() or mapping
283	>	* functions take a long time.  However, statistically, under
284	>	* random hash codes, this is not a common problem.  Ideally, the
285	>	* frequency of nodes in bins follows a Poisson distribution
286	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
287	>	* parameter of about 0.5 on average, given the resizing threshold
288	>	* of 0.75, although with a large variance because of resizing
289	>	* granularity. Ignoring variance, the expected occurrences of
290	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
291	>	* first values are:
292	>	*
293	>	* 0:    0.60653066
294	>	* 1:    0.30326533
295	>	* 2:    0.07581633
296	>	* 3:    0.01263606
297	>	* 4:    0.00157952
298	>	* 5:    0.00015795
299	>	* 6:    0.00001316
300	>	* 7:    0.00000094
301	>	* 8:    0.00000006
302	>	* more: less than 1 in ten million
303	>	*
304	>	* Lock contention probability for two threads accessing distinct
305	>	* elements is roughly 1 / (8 * #elements) under random hashes.
306	>	*
307	>	* Actual hash code distributions encountered in practice
308	>	* sometimes deviate significantly from uniform randomness.  This
309	>	* includes the case when N > (1<<30), so some keys MUST collide.
310	>	* Similarly for dumb or hostile usages in which multiple keys are
311	>	* designed to have identical hash codes. Also, although we guard
312	>	* against the worst effects of this (see method spread), sets of
313	>	* hashes may differ only in bits that do not impact their bin
314	>	* index for a given power-of-two mask.  So we use a secondary
315	>	* strategy that applies when the number of nodes in a bin exceeds
316	>	* a threshold, and at least one of the keys implements
317	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
318	>	* (a specialized form of red-black trees), bounding search time
319	>	* to O(log N).  Each search step in a TreeBin is around twice as
320	>	* slow as in a regular list, but given that N cannot exceed
321	>	* (1<<64) (before running out of addresses) this bounds search
322	>	* steps, lock hold times, etc, to reasonable constants (roughly
323	>	* 100 nodes inspected per operation worst case) so long as keys
324	>	* are Comparable (which is very common -- String, Long, etc).
325	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
326	>	* traversal pointers as regular nodes, so can be traversed in
327	>	* iterators in the same way.
328	>	*
329	>	* The table is resized when occupancy exceeds a percentage
330	>	* threshold (nominally, 0.75, but see below).  Any thread
331	>	* noticing an overfull bin may assist in resizing after the
332	>	* initiating thread allocates and sets up the replacement
333	>	* array. However, rather than stalling, these other threads may
334	>	* proceed with insertions etc.  The use of TreeBins shields us
335	>	* from the worst case effects of overfilling while resizes are in
336	>	* progress.  Resizing proceeds by transferring bins, one by one,
337	>	* from the table to the next table. To enable concurrency, the
338	>	* next table must be (incrementally) prefilled with place-holders
339	>	* serving as reverse forwarders to the old table.  Because we are
340	>	* using power-of-two expansion, the elements from each bin must
341	>	* either stay at same index, or move with a power of two
342	>	* offset. We eliminate unnecessary node creation by catching
343	>	* cases where old nodes can be reused because their next fields
344	>	* won't change.  On average, only about one-sixth of them need
345	>	* cloning when a table doubles. The nodes they replace will be
346	>	* garbage collectable as soon as they are no longer referenced by
347	>	* any reader thread that may be in the midst of concurrently
348	>	* traversing table.  Upon transfer, the old table bin contains
349	>	* only a special forwarding node (with hash field "MOVED") that
350	>	* contains the next table as its key. On encountering a
351	>	* forwarding node, access and update operations restart, using
352	>	* the new table.
353	>	*
354	>	* Each bin transfer requires its bin lock, which can stall
355	>	* waiting for locks while resizing. However, because other
356	>	* threads can join in and help resize rather than contend for
357	>	* locks, average aggregate waits become shorter as resizing
358	>	* progresses.  The transfer operation must also ensure that all
359	>	* accessible bins in both the old and new table are usable by any
360	>	* traversal.  This is arranged by proceeding from the last bin
361	>	* (table.length - 1) up towards the first.  Upon seeing a
362	>	* forwarding node, traversals (see class Traverser) arrange to
363	>	* move to the new table without revisiting nodes.  However, to
364	>	* ensure that no intervening nodes are skipped, bin splitting can
365	>	* only begin after the associated reverse-forwarders are in
366	>	* place.
367	>	*
368	>	* The traversal scheme also applies to partial traversals of
369	>	* ranges of bins (via an alternate Traverser constructor)
370	>	* to support partitioned aggregate operations.  Also, read-only
371	>	* operations give up if ever forwarded to a null table, which
372	>	* provides support for shutdown-style clearing, which is also not
373	>	* currently implemented.
374	>	*
375	>	* Lazy table initialization minimizes footprint until first use,
376	>	* and also avoids resizings when the first operation is from a
377	>	* putAll, constructor with map argument, or deserialization.
378	>	* These cases attempt to override the initial capacity settings,
379	>	* but harmlessly fail to take effect in cases of races.
380	>	*
381	>	* The element count is maintained using a specialization of
382	>	* LongAdder. We need to incorporate a specialization rather than
383	>	* just use a LongAdder in order to access implicit
384	>	* contention-sensing that leads to creation of multiple
385	>	* Cells.  The counter mechanics avoid contention on
386	>	* updates but can encounter cache thrashing if read too
387	>	* frequently during concurrent access. To avoid reading so often,
388	>	* resizing under contention is attempted only upon adding to a
389	>	* bin already holding two or more nodes. Under uniform hash
390	>	* distributions, the probability of this occurring at threshold
391	>	* is around 13%, meaning that only about 1 in 8 puts check
392	>	* threshold (and after resizing, many fewer do so). The bulk
393	>	* putAll operation further reduces contention by only committing
394	>	* count updates upon these size checks.
395	>	*
396	>	* Maintaining API and serialization compatibility with previous
397	>	* versions of this class introduces several oddities. Mainly: We
398	>	* leave untouched but unused constructor arguments refering to
399	>	* concurrencyLevel. We accept a loadFactor constructor argument,
400	>	* but apply it only to initial table capacity (which is the only
401	>	* time that we can guarantee to honor it.) We also declare an
402	>	* unused "Segment" class that is instantiated in minimal form
403	>	* only when serializing.
404		*/
405
406		/* ---------------- Constants -------------- */
407
408		/**
409	<	* The default initial capacity for this table,
410	<	* used when not otherwise specified in a constructor.
409	>	* The largest possible table capacity.  This value must be
410	>	* exactly 1<<30 to stay within Java array allocation and indexing
411	>	* bounds for power of two table sizes, and is further required
412	>	* because the top two bits of 32bit hash fields are used for
413	>	* control purposes.
414		*/
415	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
415	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
416
417		/**
418	<	* The default load factor for this table, used when not
419	<	* otherwise specified in a constructor.
418	>	* The default initial table capacity.  Must be a power of 2
419	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
420		*/
421	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
421	>	private static final int DEFAULT_CAPACITY = 16;
422
423		/**
424	<	* The default concurrency level for this table, used when not
425	<	* otherwise specified in a constructor.
424	>	* The largest possible (non-power of two) array size.
425	>	* Needed by toArray and related methods.
426		*/
427	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
427	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
428
429		/**
430	<	* The maximum capacity, used if a higher value is implicitly
431	<	* specified by either of the constructors with arguments.  MUST
120	<	* be a power of two <= 1<<30 to ensure that entries are indexable
121	<	* using ints.
430	>	* The default concurrency level for this table. Unused but
431	>	* defined for compatibility with previous versions of this class.
432		*/
433	<	static final int MAXIMUM_CAPACITY = 1 << 30;
433	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
434
435		/**
436	<	* The minimum capacity for per-segment tables.  Must be a power
437	<	* of two, at least two to avoid immediate resizing on next use
438	<	* after lazy construction.
436	>	* The load factor for this table. Overrides of this value in
437	>	* constructors affect only the initial table capacity.  The
438	>	* actual floating point value isn't normally used -- it is
439	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
440	>	* the associated resizing threshold.
441		*/
442	<	static final int MIN_SEGMENT_TABLE_CAPACITY = 2;
442	>	private static final float LOAD_FACTOR = 0.75f;
443
444		/**
445	<	* The maximum number of segments to allow; used to bound
446	<	* constructor arguments. Must be power of two less than 1 << 24.
445	>	* The bin count threshold for using a tree rather than list for a
446	>	* bin.  The value reflects the approximate break-even point for
447	>	* using tree-based operations.
448		*/
449	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
449	>	private static final int TREE_THRESHOLD = 8;
450
451		/**
452	<	* Number of unsynchronized retries in size and containsValue
453	<	* methods before resorting to locking. This is used to avoid
454	<	* unbounded retries if tables undergo continuous modification
455	<	* which would make it impossible to obtain an accurate result.
452	>	* Minimum number of rebinnings per transfer step. Ranges are
453	>	* subdivided to allow multiple resizer threads.  This value
454	>	* serves as a lower bound to avoid resizers encountering
455	>	* excessive memory contention.  The value should be at least
456	>	* DEFAULT_CAPACITY.
457		*/
458	<	static final int RETRIES_BEFORE_LOCK = 2;
458	>	private static final int MIN_TRANSFER_STRIDE = 16;
459	>
460	>	/*
461	>	* Encodings for Node hash fields. See above for explanation.
462	>	*/
463	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
464	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
465	>
466	>	/** Number of CPUS, to place bounds on some sizings */
467	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
468	>
469	>	/* ---------------- Counters -------------- */
470	>
471	>	// Adapted from LongAdder and Striped64.
472	>	// See their internal docs for explanation.
473	>
474	>	// A padded cell for distributing counts
475	>	static final class Cell {
476	>	volatile long p0, p1, p2, p3, p4, p5, p6;
477	>	volatile long value;
478	>	volatile long q0, q1, q2, q3, q4, q5, q6;
479	>	Cell(long x) { value = x; }
480	>	}
481
482		/* ---------------- Fields -------------- */
483
484		/**
485	<	* Mask value for indexing into segments. The upper bits of a
486	<	* key's hash code are used to choose the segment.
485	>	* The array of bins. Lazily initialized upon first insertion.
486	>	* Size is always a power of two. Accessed directly by iterators.
487		*/
488	<	final int segmentMask;
488	>	transient volatile Node<V>[] table;
489
490		/**
491	<	* Shift value for indexing within segments.
491	>	* The next table to use; non-null only while resizing.
492		*/
493	<	final int segmentShift;
493	>	private transient volatile Node<V>[] nextTable;
494
495		/**
496	<	* The segments, each of which is a specialized hash table.
496	>	* Base counter value, used mainly when there is no contention,
497	>	* but also as a fallback during table initialization
498	>	* races. Updated via CAS.
499		*/
500	<	final Segment<K,V>[] segments;
500	>	private transient volatile long baseCount;
501
502	<	transient Set<K> keySet;
503	<	transient Set<Map.Entry<K,V>> entrySet;
504	<	transient Collection<V> values;
502	>	/**
503	>	* Table initialization and resizing control.  When negative, the
504	>	* table is being initialized or resized: -1 for initialization,
505	>	* else -(1 + the number of active resizing threads).  Otherwise,
506	>	* when table is null, holds the initial table size to use upon
507	>	* creation, or 0 for default. After initialization, holds the
508	>	* next element count value upon which to resize the table.
509	>	*/
510	>	private transient volatile int sizeCtl;
511
512		/**
513	<	* ConcurrentHashMap list entry. Note that this is never exported
170	<	* out as a user-visible Map.Entry.
513	>	* The next table index (plus one) to split while resizing.
514		*/
515	<	static final class HashEntry<K,V> {
515	>	private transient volatile int transferIndex;
516	>
517	>	/**
518	>	* The least available table index to split while resizing.
519	>	*/
520	>	private transient volatile int transferOrigin;
521	>
522	>	/**
523	>	* Spinlock (locked via CAS) used when resizing and/or creating Cells.
524	>	*/
525	>	private transient volatile int cellsBusy;
526	>
527	>	/**
528	>	* Table of counter cells. When non-null, size is a power of 2.
529	>	*/
530	>	private transient volatile Cell[] counterCells;
531	>
532	>	// views
533	>	private transient KeySetView<K,V> keySet;
534	>	private transient ValuesView<K,V> values;
535	>	private transient EntrySetView<K,V> entrySet;
536	>
537	>	/** For serialization compatibility. Null unless serialized; see below */
538	>	private Segment<K,V>[] segments;
539	>
540	>	/* ---------------- Table element access -------------- */
541	>
542	>	/*
543	>	* Volatile access methods are used for table elements as well as
544	>	* elements of in-progress next table while resizing.  Uses are
545	>	* null checked by callers, and implicitly bounds-checked, relying
546	>	* on the invariants that tab arrays have non-zero size, and all
547	>	* indices are masked with (tab.length - 1) which is never
548	>	* negative and always less than length. Note that, to be correct
549	>	* wrt arbitrary concurrency errors by users, bounds checks must
550	>	* operate on local variables, which accounts for some odd-looking
551	>	* inline assignments below.
552	>	*/
553	>
554	>	@SuppressWarnings("unchecked") static final <V> Node<V> tabAt
555	>	(Node<V>[] tab, int i) { // used by Traverser
556	>	return (Node<V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
557	>	}
558	>
559	>	private static final <V> boolean casTabAt
560	>	(Node<V>[] tab, int i, Node<V> c, Node<V> v) {
561	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
562	>	}
563	>
564	>	private static final <V> void setTabAt
565	>	(Node<V>[] tab, int i, Node<V> v) {
566	>	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
567	>	}
568	>
569	>	/* ---------------- Nodes -------------- */
570	>
571	>	/**
572	>	* Key-value entry. Note that this is never exported out as a
573	>	* user-visible Map.Entry (see MapEntry below). Nodes with a hash
574	>	* field of MOVED are special, and do not contain user keys or
575	>	* values.  Otherwise, keys are never null, and null val fields
576	>	* indicate that a node is in the process of being deleted or
577	>	* created. For purposes of read-only access, a key may be read
578	>	* before a val, but can only be used after checking val to be
579	>	* non-null.
580	>	*/
581	>	static class Node<V> {
582		final int hash;
583	<	final K key;
584	<	volatile V value;
585	<	volatile HashEntry<K,V> next;
583	>	final Object key;
584	>	volatile V val;
585	>	volatile Node<V> next;
586
587	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
587	>	Node(int hash, Object key, V val, Node<V> next) {
588		this.hash = hash;
589		this.key = key;
590	<	this.value = value;
590	>	this.val = val;
591		this.next = next;
592		}
593	+	}
594
595	<	/**
186	<	* Sets next field with volatile write semantics.  (See above
187	<	* about use of putOrderedObject.)
188	<	*/
189	<	final void setNext(HashEntry<K,V> n) {
190	<	UNSAFE.putOrderedObject(this, nextOffset, n);
191	<	}
595	>	/* ---------------- TreeBins -------------- */
596
597	<	// Unsafe mechanics
598	<	static final sun.misc.Unsafe UNSAFE;
599	<	static final long nextOffset;
600	<	static {
601	<	try {
602	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
603	<	Class<?> k = HashEntry.class;
604	<	nextOffset = UNSAFE.objectFieldOffset
605	<	(k.getDeclaredField("next"));
606	<	} catch (Exception e) {
607	<	throw new Error(e);
608	<	}
597	>	/**
598	>	* Nodes for use in TreeBins
599	>	*/
600	>	static final class TreeNode<V> extends Node<V> {
601	>	TreeNode<V> parent;  // red-black tree links
602	>	TreeNode<V> left;
603	>	TreeNode<V> right;
604	>	TreeNode<V> prev;    // needed to unlink next upon deletion
605	>	boolean red;
606	>
607	>	TreeNode(int hash, Object key, V val, Node<V> next, TreeNode<V> parent) {
608	>	super(hash, key, val, next);
609	>	this.parent = parent;
610		}
611		}
612
613		/**
614	<	* Gets the ith element of given table (if nonnull) with volatile
615	<	* read semantics. Note: This is manually integrated into a few
616	<	* performance-sensitive methods to reduce call overhead.
617	<	*/
618	<	@SuppressWarnings("unchecked")
619	<	static final <K,V> HashEntry<K,V> entryAt(HashEntry<K,V>[] tab, int i) {
620	<	return (tab == null) ? null :
621	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
622	<	(tab, ((long)i << TSHIFT) + TBASE);
623	<	}
624	<
625	<	/**
626	<	* Sets the ith element of given table, with volatile write
627	<	* semantics. (See above about use of putOrderedObject.)
628	<	*/
629	<	static final <K,V> void setEntryAt(HashEntry<K,V>[] tab, int i,
630	<	HashEntry<K,V> e) {
631	<	UNSAFE.putOrderedObject(tab, ((long)i << TSHIFT) + TBASE, e);
632	<	}
633	<
634	<	/**
635	<	* Applies a supplemental hash function to a given hashCode, which
636	<	* defends against poor quality hash functions.  This is critical
637	<	* because ConcurrentHashMap uses power-of-two length hash tables,
638	<	* that otherwise encounter collisions for hashCodes that do not
639	<	* differ in lower or upper bits.
640	<	*/
641	<	private static int hash(int h) {
642	<	// Spread bits to regularize both segment and index locations,
643	<	// using variant of single-word Wang/Jenkins hash.
644	<	h += (h <<  15) ^ 0xffffcd7d;
645	<	h ^= (h >>> 10);
646	<	h += (h <<   3);
647	<	h ^= (h >>>  6);
648	<	h += (h <<   2) + (h << 14);
649	<	return h ^ (h >>> 16);
650	<	}
651	<
652	<	/**
653	<	* Segments are specialized versions of hash tables.  This
654	<	* subclasses from ReentrantLock opportunistically, just to
655	<	* simplify some locking and avoid separate construction.
656	<	*/
252	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
253	<	/*
254	<	* Segments maintain a table of entry lists that are always
255	<	* kept in a consistent state, so can be read (via volatile
256	<	* reads of segments and tables) without locking.  This
257	<	* requires replicating nodes when necessary during table
258	<	* resizing, so the old lists can be traversed by readers
259	<	* still using old version of table.
260	<	*
261	<	* This class defines only mutative methods requiring locking.
262	<	* Except as noted, the methods of this class perform the
263	<	* per-segment versions of ConcurrentHashMap methods.  (Other
264	<	* methods are integrated directly into ConcurrentHashMap
265	<	* methods.) These mutative methods use a form of controlled
266	<	* spinning on contention via methods scanAndLock and
267	<	* scanAndLockForPut. These intersperse tryLocks with
268	<	* traversals to locate nodes.  The main benefit is to absorb
269	<	* cache misses (which are very common for hash tables) while
270	<	* obtaining locks so that traversal is faster once
271	<	* acquired. We do not actually use the found nodes since they
272	<	* must be re-acquired under lock anyway to ensure sequential
273	<	* consistency of updates (and in any case may be undetectably
274	<	* stale), but they will normally be much faster to re-locate.
275	<	* Also, scanAndLockForPut speculatively creates a fresh node
276	<	* to use in put if no node is found.
277	<	*/
278	<
614	>	* A specialized form of red-black tree for use in bins
615	>	* whose size exceeds a threshold.
616	>	*
617	>	* TreeBins use a special form of comparison for search and
618	>	* related operations (which is the main reason we cannot use
619	>	* existing collections such as TreeMaps). TreeBins contain
620	>	* Comparable elements, but may contain others, as well as
621	>	* elements that are Comparable but not necessarily Comparable<T>
622	>	* for the same T, so we cannot invoke compareTo among them. To
623	>	* handle this, the tree is ordered primarily by hash value, then
624	>	* by getClass().getName() order, and then by Comparator order
625	>	* among elements of the same class.  On lookup at a node, if
626	>	* elements are not comparable or compare as 0, both left and
627	>	* right children may need to be searched in the case of tied hash
628	>	* values. (This corresponds to the full list search that would be
629	>	* necessary if all elements were non-Comparable and had tied
630	>	* hashes.)  The red-black balancing code is updated from
631	>	* pre-jdk-collections
632	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
633	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
634	>	* Algorithms" (CLR).
635	>	*
636	>	* TreeBins also maintain a separate locking discipline than
637	>	* regular bins. Because they are forwarded via special MOVED
638	>	* nodes at bin heads (which can never change once established),
639	>	* we cannot use those nodes as locks. Instead, TreeBin
640	>	* extends AbstractQueuedSynchronizer to support a simple form of
641	>	* read-write lock. For update operations and table validation,
642	>	* the exclusive form of lock behaves in the same way as bin-head
643	>	* locks. However, lookups use shared read-lock mechanics to allow
644	>	* multiple readers in the absence of writers.  Additionally,
645	>	* these lookups do not ever block: While the lock is not
646	>	* available, they proceed along the slow traversal path (via
647	>	* next-pointers) until the lock becomes available or the list is
648	>	* exhausted, whichever comes first. (These cases are not fast,
649	>	* but maximize aggregate expected throughput.)  The AQS mechanics
650	>	* for doing this are straightforward.  The lock state is held as
651	>	* AQS getState().  Read counts are negative; the write count (1)
652	>	* is positive.  There are no signalling preferences among readers
653	>	* and writers. Since we don't need to export full Lock API, we
654	>	* just override the minimal AQS methods and use them directly.
655	>	*/
656	>	static final class TreeBin<V> extends AbstractQueuedSynchronizer {
657		private static final long serialVersionUID = 2249069246763182397L;
658	+	transient TreeNode<V> root;  // root of tree
659	+	transient TreeNode<V> first; // head of next-pointer list
660
661	<	/**
662	<	* The maximum number of times to tryLock in a prescan before
663	<	* possibly blocking on acquire in preparation for a locked
664	<	* segment operation. On multiprocessors, using a bounded
665	<	* number of retries maintains cache acquired while locating
666	<	* nodes.
667	<	*/
668	<	static final int MAX_SCAN_RETRIES =
669	<	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
661	>	/* AQS overrides */
662	>	public final boolean isHeldExclusively() { return getState() > 0; }
663	>	public final boolean tryAcquire(int ignore) {
664	>	if (compareAndSetState(0, 1)) {
665	>	setExclusiveOwnerThread(Thread.currentThread());
666	>	return true;
667	>	}
668	>	return false;
669	>	}
670	>	public final boolean tryRelease(int ignore) {
671	>	setExclusiveOwnerThread(null);
672	>	setState(0);
673	>	return true;
674	>	}
675	>	public final int tryAcquireShared(int ignore) {
676	>	for (int c;;) {
677	>	if ((c = getState()) > 0)
678	>	return -1;
679	>	if (compareAndSetState(c, c -1))
680	>	return 1;
681	>	}
682	>	}
683	>	public final boolean tryReleaseShared(int ignore) {
684	>	int c;
685	>	do {} while (!compareAndSetState(c = getState(), c + 1));
686	>	return c == -1;
687	>	}
688	>
689	>	/** From CLR */
690	>	private void rotateLeft(TreeNode<V> p) {
691	>	if (p != null) {
692	>	TreeNode<V> r = p.right, pp, rl;
693	>	if ((rl = p.right = r.left) != null)
694	>	rl.parent = p;
695	>	if ((pp = r.parent = p.parent) == null)
696	>	root = r;
697	>	else if (pp.left == p)
698	>	pp.left = r;
699	>	else
700	>	pp.right = r;
701	>	r.left = p;
702	>	p.parent = r;
703	>	}
704	>	}
705
706	<	/**
707	<	* The per-segment table. Elements are accessed via
708	<	* entryAt/setEntryAt providing volatile semantics.
709	<	*/
710	<	transient volatile HashEntry<K,V>[] table;
706	>	/** From CLR */
707	>	private void rotateRight(TreeNode<V> p) {
708	>	if (p != null) {
709	>	TreeNode<V> l = p.left, pp, lr;
710	>	if ((lr = p.left = l.right) != null)
711	>	lr.parent = p;
712	>	if ((pp = l.parent = p.parent) == null)
713	>	root = l;
714	>	else if (pp.right == p)
715	>	pp.right = l;
716	>	else
717	>	pp.left = l;
718	>	l.right = p;
719	>	p.parent = l;
720	>	}
721	>	}
722
723		/**
724	<	* The number of elements. Accessed only either within locks
725	<	* or among other volatile reads that maintain visibility.
724	>	* Returns the TreeNode (or null if not found) for the given key
725	>	* starting at given root.
726		*/
727	<	transient int count;
727	>	@SuppressWarnings("unchecked") final TreeNode<V> getTreeNode
728	>	(int h, Object k, TreeNode<V> p) {
729	>	Class<?> c = k.getClass();
730	>	while (p != null) {
731	>	int dir, ph;  Object pk; Class<?> pc;
732	>	if ((ph = p.hash) == h) {
733	>	if ((pk = p.key) == k || k.equals(pk))
734	>	return p;
735	>	if (c != (pc = pk.getClass()) ||
736	>	!(k instanceof Comparable) ||
737	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
738	>	if ((dir = (c == pc) ? 0 :
739	>	c.getName().compareTo(pc.getName())) == 0) {
740	>	TreeNode<V> r = null, pl, pr; // check both sides
741	>	if ((pr = p.right) != null && h >= pr.hash &&
742	>	(r = getTreeNode(h, k, pr)) != null)
743	>	return r;
744	>	else if ((pl = p.left) != null && h <= pl.hash)
745	>	dir = -1;
746	>	else // nothing there
747	>	return null;
748	>	}
749	>	}
750	>	}
751	>	else
752	>	dir = (h < ph) ? -1 : 1;
753	>	p = (dir > 0) ? p.right : p.left;
754	>	}
755	>	return null;
756	>	}
757
758		/**
759	<	* The total number of mutative operations in this segment.
760	<	* Even though this may overflows 32 bits, it provides
761	<	* sufficient accuracy for stability checks in CHM isEmpty()
307	<	* and size() methods.  Accessed only either within locks or
308	<	* among other volatile reads that maintain visibility.
759	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
760	>	* read-lock to call getTreeNode, but during failure to get
761	>	* lock, searches along next links.
762		*/
763	<	transient int modCount;
763	>	final V getValue(int h, Object k) {
764	>	Node<V> r = null;
765	>	int c = getState(); // Must read lock state first
766	>	for (Node<V> e = first; e != null; e = e.next) {
767	>	if (c <= 0 && compareAndSetState(c, c - 1)) {
768	>	try {
769	>	r = getTreeNode(h, k, root);
770	>	} finally {
771	>	releaseShared(0);
772	>	}
773	>	break;
774	>	}
775	>	else if (e.hash == h && k.equals(e.key)) {
776	>	r = e;
777	>	break;
778	>	}
779	>	else
780	>	c = getState();
781	>	}
782	>	return r == null ? null : r.val;
783	>	}
784
785		/**
786	<	* The table is rehashed when its size exceeds this threshold.
787	<	* (The value of this field is always <tt>(int)(capacity *
315	<	* loadFactor)</tt>.)
786	>	* Finds or adds a node.
787	>	* @return null if added
788		*/
789	<	transient int threshold;
789	>	@SuppressWarnings("unchecked") final TreeNode<V> putTreeNode
790	>	(int h, Object k, V v) {
791	>	Class<?> c = k.getClass();
792	>	TreeNode<V> pp = root, p = null;
793	>	int dir = 0;
794	>	while (pp != null) { // find existing node or leaf to insert at
795	>	int ph;  Object pk; Class<?> pc;
796	>	p = pp;
797	>	if ((ph = p.hash) == h) {
798	>	if ((pk = p.key) == k || k.equals(pk))
799	>	return p;
800	>	if (c != (pc = pk.getClass()) ||
801	>	!(k instanceof Comparable) ||
802	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
803	>	TreeNode<V> s = null, r = null, pr;
804	>	if ((dir = (c == pc) ? 0 :
805	>	c.getName().compareTo(pc.getName())) == 0) {
806	>	if ((pr = p.right) != null && h >= pr.hash &&
807	>	(r = getTreeNode(h, k, pr)) != null)
808	>	return r;
809	>	else // continue left
810	>	dir = -1;
811	>	}
812	>	else if ((pr = p.right) != null && h >= pr.hash)
813	>	s = pr;
814	>	if (s != null && (r = getTreeNode(h, k, s)) != null)
815	>	return r;
816	>	}
817	>	}
818	>	else
819	>	dir = (h < ph) ? -1 : 1;
820	>	pp = (dir > 0) ? p.right : p.left;
821	>	}
822	>
823	>	TreeNode<V> f = first;
824	>	TreeNode<V> x = first = new TreeNode<V>(h, k, v, f, p);
825	>	if (p == null)
826	>	root = x;
827	>	else { // attach and rebalance; adapted from CLR
828	>	TreeNode<V> xp, xpp;
829	>	if (f != null)
830	>	f.prev = x;
831	>	if (dir <= 0)
832	>	p.left = x;
833	>	else
834	>	p.right = x;
835	>	x.red = true;
836	>	while (x != null && (xp = x.parent) != null && xp.red &&
837	>	(xpp = xp.parent) != null) {
838	>	TreeNode<V> xppl = xpp.left;
839	>	if (xp == xppl) {
840	>	TreeNode<V> y = xpp.right;
841	>	if (y != null && y.red) {
842	>	y.red = false;
843	>	xp.red = false;
844	>	xpp.red = true;
845	>	x = xpp;
846	>	}
847	>	else {
848	>	if (x == xp.right) {
849	>	rotateLeft(x = xp);
850	>	xpp = (xp = x.parent) == null ? null : xp.parent;
851	>	}
852	>	if (xp != null) {
853	>	xp.red = false;
854	>	if (xpp != null) {
855	>	xpp.red = true;
856	>	rotateRight(xpp);
857	>	}
858	>	}
859	>	}
860	>	}
861	>	else {
862	>	TreeNode<V> y = xppl;
863	>	if (y != null && y.red) {
864	>	y.red = false;
865	>	xp.red = false;
866	>	xpp.red = true;
867	>	x = xpp;
868	>	}
869	>	else {
870	>	if (x == xp.left) {
871	>	rotateRight(x = xp);
872	>	xpp = (xp = x.parent) == null ? null : xp.parent;
873	>	}
874	>	if (xp != null) {
875	>	xp.red = false;
876	>	if (xpp != null) {
877	>	xpp.red = true;
878	>	rotateLeft(xpp);
879	>	}
880	>	}
881	>	}
882	>	}
883	>	}
884	>	TreeNode<V> r = root;
885	>	if (r != null && r.red)
886	>	r.red = false;
887	>	}
888	>	return null;
889	>	}
890
891		/**
892	<	* The load factor for the hash table.  Even though this value
893	<	* is same for all segments, it is replicated to avoid needing
894	<	* links to outer object.
895	<	* @serial
892	>	* Removes the given node, that must be present before this
893	>	* call.  This is messier than typical red-black deletion code
894	>	* because we cannot swap the contents of an interior node
895	>	* with a leaf successor that is pinned by "next" pointers
896	>	* that are accessible independently of lock. So instead we
897	>	* swap the tree linkages.
898		*/
899	<	final float loadFactor;
899	>	final void deleteTreeNode(TreeNode<V> p) {
900	>	TreeNode<V> next = (TreeNode<V>)p.next; // unlink traversal pointers
901	>	TreeNode<V> pred = p.prev;
902	>	if (pred == null)
903	>	first = next;
904	>	else
905	>	pred.next = next;
906	>	if (next != null)
907	>	next.prev = pred;
908	>	TreeNode<V> replacement;
909	>	TreeNode<V> pl = p.left;
910	>	TreeNode<V> pr = p.right;
911	>	if (pl != null && pr != null) {
912	>	TreeNode<V> s = pr, sl;
913	>	while ((sl = s.left) != null) // find successor
914	>	s = sl;
915	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
916	>	TreeNode<V> sr = s.right;
917	>	TreeNode<V> pp = p.parent;
918	>	if (s == pr) { // p was s's direct parent
919	>	p.parent = s;
920	>	s.right = p;
921	>	}
922	>	else {
923	>	TreeNode<V> sp = s.parent;
924	>	if ((p.parent = sp) != null) {
925	>	if (s == sp.left)
926	>	sp.left = p;
927	>	else
928	>	sp.right = p;
929	>	}
930	>	if ((s.right = pr) != null)
931	>	pr.parent = s;
932	>	}
933	>	p.left = null;
934	>	if ((p.right = sr) != null)
935	>	sr.parent = p;
936	>	if ((s.left = pl) != null)
937	>	pl.parent = s;
938	>	if ((s.parent = pp) == null)
939	>	root = s;
940	>	else if (p == pp.left)
941	>	pp.left = s;
942	>	else
943	>	pp.right = s;
944	>	replacement = sr;
945	>	}
946	>	else
947	>	replacement = (pl != null) ? pl : pr;
948	>	TreeNode<V> pp = p.parent;
949	>	if (replacement == null) {
950	>	if (pp == null) {
951	>	root = null;
952	>	return;
953	>	}
954	>	replacement = p;
955	>	}
956	>	else {
957	>	replacement.parent = pp;
958	>	if (pp == null)
959	>	root = replacement;
960	>	else if (p == pp.left)
961	>	pp.left = replacement;
962	>	else
963	>	pp.right = replacement;
964	>	p.left = p.right = p.parent = null;
965	>	}
966	>	if (!p.red) { // rebalance, from CLR
967	>	TreeNode<V> x = replacement;
968	>	while (x != null) {
969	>	TreeNode<V> xp, xpl;
970	>	if (x.red || (xp = x.parent) == null) {
971	>	x.red = false;
972	>	break;
973	>	}
974	>	if (x == (xpl = xp.left)) {
975	>	TreeNode<V> sib = xp.right;
976	>	if (sib != null && sib.red) {
977	>	sib.red = false;
978	>	xp.red = true;
979	>	rotateLeft(xp);
980	>	sib = (xp = x.parent) == null ? null : xp.right;
981	>	}
982	>	if (sib == null)
983	>	x = xp;
984	>	else {
985	>	TreeNode<V> sl = sib.left, sr = sib.right;
986	>	if ((sr == null || !sr.red) &&
987	>	(sl == null || !sl.red)) {
988	>	sib.red = true;
989	>	x = xp;
990	>	}
991	>	else {
992	>	if (sr == null || !sr.red) {
993	>	if (sl != null)
994	>	sl.red = false;
995	>	sib.red = true;
996	>	rotateRight(sib);
997	>	sib = (xp = x.parent) == null ?
998	>	null : xp.right;
999	>	}
1000	>	if (sib != null) {
1001	>	sib.red = (xp == null) ? false : xp.red;
1002	>	if ((sr = sib.right) != null)
1003	>	sr.red = false;
1004	>	}
1005	>	if (xp != null) {
1006	>	xp.red = false;
1007	>	rotateLeft(xp);
1008	>	}
1009	>	x = root;
1010	>	}
1011	>	}
1012	>	}
1013	>	else { // symmetric
1014	>	TreeNode<V> sib = xpl;
1015	>	if (sib != null && sib.red) {
1016	>	sib.red = false;
1017	>	xp.red = true;
1018	>	rotateRight(xp);
1019	>	sib = (xp = x.parent) == null ? null : xp.left;
1020	>	}
1021	>	if (sib == null)
1022	>	x = xp;
1023	>	else {
1024	>	TreeNode<V> sl = sib.left, sr = sib.right;
1025	>	if ((sl == null || !sl.red) &&
1026	>	(sr == null || !sr.red)) {
1027	>	sib.red = true;
1028	>	x = xp;
1029	>	}
1030	>	else {
1031	>	if (sl == null || !sl.red) {
1032	>	if (sr != null)
1033	>	sr.red = false;
1034	>	sib.red = true;
1035	>	rotateLeft(sib);
1036	>	sib = (xp = x.parent) == null ?
1037	>	null : xp.left;
1038	>	}
1039	>	if (sib != null) {
1040	>	sib.red = (xp == null) ? false : xp.red;
1041	>	if ((sl = sib.left) != null)
1042	>	sl.red = false;
1043	>	}
1044	>	if (xp != null) {
1045	>	xp.red = false;
1046	>	rotateRight(xp);
1047	>	}
1048	>	x = root;
1049	>	}
1050	>	}
1051	>	}
1052	>	}
1053	>	}
1054	>	if (p == replacement && (pp = p.parent) != null) {
1055	>	if (p == pp.left) // detach pointers
1056	>	pp.left = null;
1057	>	else if (p == pp.right)
1058	>	pp.right = null;
1059	>	p.parent = null;
1060	>	}
1061	>	}
1062	>	}
1063	>
1064	>	/* ---------------- Collision reduction methods -------------- */
1065	>
1066	>	/**
1067	>	* Spreads higher bits to lower, and also forces top bit to 0.
1068	>	* Because the table uses power-of-two masking, sets of hashes
1069	>	* that vary only in bits above the current mask will always
1070	>	* collide. (Among known examples are sets of Float keys holding
1071	>	* consecutive whole numbers in small tables.)  To counter this,
1072	>	* we apply a transform that spreads the impact of higher bits
1073	>	* downward. There is a tradeoff between speed, utility, and
1074	>	* quality of bit-spreading. Because many common sets of hashes
1075	>	* are already reasonably distributed across bits (so don't benefit
1076	>	* from spreading), and because we use trees to handle large sets
1077	>	* of collisions in bins, we don't need excessively high quality.
1078	>	*/
1079	>	private static final int spread(int h) {
1080	>	h ^= (h >>> 18) ^ (h >>> 12);
1081	>	return (h ^ (h >>> 10)) & HASH_BITS;
1082	>	}
1083	>
1084	>	/**
1085	>	* Replaces a list bin with a tree bin if key is comparable.  Call
1086	>	* only when locked.
1087	>	*/
1088	>	private final void replaceWithTreeBin(Node<V>[] tab, int index, Object key) {
1089	>	if (key instanceof Comparable) {
1090	>	TreeBin<V> t = new TreeBin<V>();
1091	>	for (Node<V> e = tabAt(tab, index); e != null; e = e.next)
1092	>	t.putTreeNode(e.hash, e.key, e.val);
1093	>	setTabAt(tab, index, new Node<V>(MOVED, t, null, null));
1094	>	}
1095	>	}
1096
1097	<	Segment(float lf, int threshold, HashEntry<K,V>[] tab) {
1098	<	this.loadFactor = lf;
1099	<	this.threshold = threshold;
1100	<	this.table = tab;
1097	>	/* ---------------- Internal access and update methods -------------- */
1098	>
1099	>	/** Implementation for get and containsKey */
1100	>	@SuppressWarnings("unchecked") private final V internalGet(Object k) {
1101	>	int h = spread(k.hashCode());
1102	>	retry: for (Node<V>[] tab = table; tab != null;) {
1103	>	Node<V> e; Object ek; V ev; int eh; // locals to read fields once
1104	>	for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1105	>	if ((eh = e.hash) < 0) {
1106	>	if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1107	>	return ((TreeBin<V>)ek).getValue(h, k);
1108	>	else {                      // restart with new table
1109	>	tab = (Node<V>[])ek;
1110	>	continue retry;
1111	>	}
1112	>	}
1113	>	else if (eh == h && (ev = e.val) != null &&
1114	>	((ek = e.key) == k || k.equals(ek)))
1115	>	return ev;
1116	>	}
1117	>	break;
1118		}
1119	+	return null;
1120	+	}
1121
1122	<	final V put(K key, int hash, V value, boolean onlyIfAbsent) {
1123	<	HashEntry<K,V> node = tryLock() ? null :
1124	<	scanAndLockForPut(key, hash, value);
1125	<	V oldValue;
1126	<	try {
1127	<	HashEntry<K,V>[] tab = table;
1128	<	int index = (tab.length - 1) & hash;
1129	<	HashEntry<K,V> first = entryAt(tab, index);
1130	<	for (HashEntry<K,V> e = first;;) {
1131	<	if (e != null) {
1132	<	K k;
1133	<	if ((k = e.key) == key ||
1134	<	(e.hash == hash && key.equals(k))) {
1135	<	oldValue = e.value;
1136	<	if (!onlyIfAbsent) {
1137	<	e.value = value;
1138	<	++modCount;
1122	>	/**
1123	>	* Implementation for the four public remove/replace methods:
1124	>	* Replaces node value with v, conditional upon match of cv if
1125	>	* non-null.  If resulting value is null, delete.
1126	>	*/
1127	>	@SuppressWarnings("unchecked") private final V internalReplace
1128	>	(Object k, V v, Object cv) {
1129	>	int h = spread(k.hashCode());
1130	>	V oldVal = null;
1131	>	for (Node<V>[] tab = table;;) {
1132	>	Node<V> f; int i, fh; Object fk;
1133	>	if (tab == null ||
1134	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1135	>	break;
1136	>	else if ((fh = f.hash) < 0) {
1137	>	if ((fk = f.key) instanceof TreeBin) {
1138	>	TreeBin<V> t = (TreeBin<V>)fk;
1139	>	boolean validated = false;
1140	>	boolean deleted = false;
1141	>	t.acquire(0);
1142	>	try {
1143	>	if (tabAt(tab, i) == f) {
1144	>	validated = true;
1145	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1146	>	if (p != null) {
1147	>	V pv = p.val;
1148	>	if (cv == null || cv == pv || cv.equals(pv)) {
1149	>	oldVal = pv;
1150	>	if ((p.val = v) == null) {
1151	>	deleted = true;
1152	>	t.deleteTreeNode(p);
1153	>	}
1154	>	}
1155		}
351	–	break;
1156		}
1157	<	e = e.next;
1157	>	} finally {
1158	>	t.release(0);
1159		}
1160	<	else {
1161	<	if (node != null)
1162	<	node.setNext(first);
358	<	else
359	<	node = new HashEntry<K,V>(hash, key, value, first);
360	<	int c = count + 1;
361	<	if (c > threshold && tab.length < MAXIMUM_CAPACITY)
362	<	rehash(node);
363	<	else
364	<	setEntryAt(tab, index, node);
365	<	++modCount;
366	<	count = c;
367	<	oldValue = null;
1160	>	if (validated) {
1161	>	if (deleted)
1162	>	addCount(-1L, -1);
1163		break;
1164		}
1165		}
1166	<	} finally {
1167	<	unlock();
1166	>	else
1167	>	tab = (Node<V>[])fk;
1168	>	}
1169	>	else if (fh != h && f.next == null) // precheck
1170	>	break;                          // rules out possible existence
1171	>	else {
1172	>	boolean validated = false;
1173	>	boolean deleted = false;
1174	>	synchronized (f) {
1175	>	if (tabAt(tab, i) == f) {
1176	>	validated = true;
1177	>	for (Node<V> e = f, pred = null;;) {
1178	>	Object ek; V ev;
1179	>	if (e.hash == h &&
1180	>	((ev = e.val) != null) &&
1181	>	((ek = e.key) == k || k.equals(ek))) {
1182	>	if (cv == null || cv == ev || cv.equals(ev)) {
1183	>	oldVal = ev;
1184	>	if ((e.val = v) == null) {
1185	>	deleted = true;
1186	>	Node<V> en = e.next;
1187	>	if (pred != null)
1188	>	pred.next = en;
1189	>	else
1190	>	setTabAt(tab, i, en);
1191	>	}
1192	>	}
1193	>	break;
1194	>	}
1195	>	pred = e;
1196	>	if ((e = e.next) == null)
1197	>	break;
1198	>	}
1199	>	}
1200	>	}
1201	>	if (validated) {
1202	>	if (deleted)
1203	>	addCount(-1L, -1);
1204	>	break;
1205	>	}
1206		}
374	–	return oldValue;
1207		}
1208	+	return oldVal;
1209	+	}
1210
1211	<	/**
1212	<	* Doubles size of table and repacks entries, also adding the
1213	<	* given node to new table
1214	<	*/
1215	<	@SuppressWarnings("unchecked")
1216	<	private void rehash(HashEntry<K,V> node) {
1217	<	/*
1218	<	* Reclassify nodes in each list to new table.  Because we
1219	<	* are using power-of-two expansion, the elements from
1220	<	* each bin must either stay at same index, or move with a
1221	<	* power of two offset. We eliminate unnecessary node
1222	<	* creation by catching cases where old nodes can be
1223	<	* reused because their next fields won't change.
1224	<	* Statistically, at the default threshold, only about
1225	<	* one-sixth of them need cloning when a table
1226	<	* doubles. The nodes they replace will be garbage
1227	<	* collectable as soon as they are no longer referenced by
1228	<	* any reader thread that may be in the midst of
1229	<	* concurrently traversing table. Entry accesses use plain
1230	<	* array indexing because they are followed by volatile
1231	<	* table write.
1232	<	*/
1233	<	HashEntry<K,V>[] oldTable = table;
1234	<	int oldCapacity = oldTable.length;
1235	<	int newCapacity = oldCapacity << 1;
1236	<	threshold = (int)(newCapacity * loadFactor);
1237	<	HashEntry<K,V>[] newTable =
1238	<	(HashEntry<K,V>[]) new HashEntry<?,?>[newCapacity];
1239	<	int sizeMask = newCapacity - 1;
1240	<	for (int i = 0; i < oldCapacity ; i++) {
1241	<	HashEntry<K,V> e = oldTable[i];
1242	<	if (e != null) {
1243	<	HashEntry<K,V> next = e.next;
1244	<	int idx = e.hash & sizeMask;
1245	<	if (next == null)   //  Single node on list
1246	<	newTable[idx] = e;
1247	<	else { // Reuse consecutive sequence at same slot
1248	<	HashEntry<K,V> lastRun = e;
1249	<	int lastIdx = idx;
1250	<	for (HashEntry<K,V> last = next;
1251	<	last != null;
1252	<	last = last.next) {
1253	<	int k = last.hash & sizeMask;
1254	<	if (k != lastIdx) {
1255	<	lastIdx = k;
1256	<	lastRun = last;
1257	<	}
1258	<	}
1259	<	newTable[lastIdx] = lastRun;
1260	<	// Clone remaining nodes
1261	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1262	<	V v = p.value;
1263	<	int h = p.hash;
1264	<	int k = h & sizeMask;
431	<	HashEntry<K,V> n = newTable[k];
432	<	newTable[k] = new HashEntry<K,V>(h, p.key, v, n);
433	<	}
434	<	}
435	<	}
436	<	}
437	<	int nodeIndex = node.hash & sizeMask; // add the new node
438	<	node.setNext(newTable[nodeIndex]);
439	<	newTable[nodeIndex] = node;
440	<	table = newTable;
441	<	}
442	<
443	<	/**
444	<	* Scans for a node containing given key while trying to
445	<	* acquire lock, creating and returning one if not found. Upon
446	<	* return, guarantees that lock is held. Unlike in most
447	<	* methods, calls to method equals are not screened: Since
448	<	* traversal speed doesn't matter, we might as well help warm
449	<	* up the associated code and accesses as well.
450	<	*
451	<	* @return a new node if key not found, else null
452	<	*/
453	<	private HashEntry<K,V> scanAndLockForPut(K key, int hash, V value) {
454	<	HashEntry<K,V> first = entryForHash(this, hash);
455	<	HashEntry<K,V> e = first;
456	<	HashEntry<K,V> node = null;
457	<	int retries = -1; // negative while locating node
458	<	while (!tryLock()) {
459	<	HashEntry<K,V> f; // to recheck first below
460	<	if (retries < 0) {
461	<	if (e == null) {
462	<	if (node == null) // speculatively create node
463	<	node = new HashEntry<K,V>(hash, key, value, null);
464	<	retries = 0;
1211	>	/*
1212	>	* Internal versions of insertion methods
1213	>	* All have the same basic structure as the first (internalPut):
1214	>	*  1. If table uninitialized, create
1215	>	*  2. If bin empty, try to CAS new node
1216	>	*  3. If bin stale, use new table
1217	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1218	>	*  5. Lock and validate; if valid, scan and add or update
1219	>	*
1220	>	* The putAll method differs mainly in attempting to pre-allocate
1221	>	* enough table space, and also more lazily performs count updates
1222	>	* and checks.
1223	>	*
1224	>	* Most of the function-accepting methods can't be factored nicely
1225	>	* because they require different functional forms, so instead
1226	>	* sprawl out similar mechanics.
1227	>	*/
1228	>
1229	>	/** Implementation for put and putIfAbsent */
1230	>	@SuppressWarnings("unchecked") private final V internalPut
1231	>	(K k, V v, boolean onlyIfAbsent) {
1232	>	if (k == null || v == null) throw new NullPointerException();
1233	>	int h = spread(k.hashCode());
1234	>	int len = 0;
1235	>	for (Node<V>[] tab = table;;) {
1236	>	int i, fh; Node<V> f; Object fk; V fv;
1237	>	if (tab == null)
1238	>	tab = initTable();
1239	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1240	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null)))
1241	>	break;                   // no lock when adding to empty bin
1242	>	}
1243	>	else if ((fh = f.hash) < 0) {
1244	>	if ((fk = f.key) instanceof TreeBin) {
1245	>	TreeBin<V> t = (TreeBin<V>)fk;
1246	>	V oldVal = null;
1247	>	t.acquire(0);
1248	>	try {
1249	>	if (tabAt(tab, i) == f) {
1250	>	len = 2;
1251	>	TreeNode<V> p = t.putTreeNode(h, k, v);
1252	>	if (p != null) {
1253	>	oldVal = p.val;
1254	>	if (!onlyIfAbsent)
1255	>	p.val = v;
1256	>	}
1257	>	}
1258	>	} finally {
1259	>	t.release(0);
1260	>	}
1261	>	if (len != 0) {
1262	>	if (oldVal != null)
1263	>	return oldVal;
1264	>	break;
1265		}
466	–	else if (key.equals(e.key))
467	–	retries = 0;
468	–	else
469	–	e = e.next;
1266		}
1267	<	else if (++retries > MAX_SCAN_RETRIES) {
1268	<	lock();
1267	>	else
1268	>	tab = (Node<V>[])fk;
1269	>	}
1270	>	else if (onlyIfAbsent && fh == h && (fv = f.val) != null &&
1271	>	((fk = f.key) == k || k.equals(fk))) // peek while nearby
1272	>	return fv;
1273	>	else {
1274	>	V oldVal = null;
1275	>	synchronized (f) {
1276	>	if (tabAt(tab, i) == f) {
1277	>	len = 1;
1278	>	for (Node<V> e = f;; ++len) {
1279	>	Object ek; V ev;
1280	>	if (e.hash == h &&
1281	>	(ev = e.val) != null &&
1282	>	((ek = e.key) == k || k.equals(ek))) {
1283	>	oldVal = ev;
1284	>	if (!onlyIfAbsent)
1285	>	e.val = v;
1286	>	break;
1287	>	}
1288	>	Node<V> last = e;
1289	>	if ((e = e.next) == null) {
1290	>	last.next = new Node<V>(h, k, v, null);
1291	>	if (len >= TREE_THRESHOLD)
1292	>	replaceWithTreeBin(tab, i, k);
1293	>	break;
1294	>	}
1295	>	}
1296	>	}
1297	>	}
1298	>	if (len != 0) {
1299	>	if (oldVal != null)
1300	>	return oldVal;
1301		break;
1302		}
1303	<	else if ((retries & 1) == 0 &&
476	<	(f = entryForHash(this, hash)) != first) {
477	<	e = first = f; // re-traverse if entry changed
478	<	retries = -1;
479	<	}
480	<	}
481	<	return node;
1303	>	}
1304		}
1305	+	addCount(1L, len);
1306	+	return null;
1307	+	}
1308
1309	<	/**
1310	<	* Scans for a node containing the given key while trying to
1311	<	* acquire lock for a remove or replace operation. Upon
1312	<	* return, guarantees that lock is held.  Note that we must
1313	<	* lock even if the key is not found, to ensure sequential
1314	<	* consistency of updates.
1315	<	*/
1316	<	private void scanAndLock(Object key, int hash) {
1317	<	// similar to but simpler than scanAndLockForPut
1318	<	HashEntry<K,V> first = entryForHash(this, hash);
1319	<	HashEntry<K,V> e = first;
1320	<	int retries = -1;
1321	<	while (!tryLock()) {
1322	<	HashEntry<K,V> f;
1323	<	if (retries < 0) {
1324	<	if (e == null || key.equals(e.key))
1325	<	retries = 0;
1326	<	else
1327	<	e = e.next;
1309	>	/** Implementation for computeIfAbsent */
1310	>	@SuppressWarnings("unchecked") private final V internalComputeIfAbsent
1311	>	(K k, Function<? super K, ? extends V> mf) {
1312	>	if (k == null || mf == null)
1313	>	throw new NullPointerException();
1314	>	int h = spread(k.hashCode());
1315	>	V val = null;
1316	>	int len = 0;
1317	>	for (Node<V>[] tab = table;;) {
1318	>	Node<V> f; int i; Object fk;
1319	>	if (tab == null)
1320	>	tab = initTable();
1321	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1322	>	Node<V> node = new Node<V>(h, k, null, null);
1323	>	synchronized (node) {
1324	>	if (casTabAt(tab, i, null, node)) {
1325	>	len = 1;
1326	>	try {
1327	>	if ((val = mf.apply(k)) != null)
1328	>	node.val = val;
1329	>	} finally {
1330	>	if (val == null)
1331	>	setTabAt(tab, i, null);
1332	>	}
1333	>	}
1334		}
1335	<	else if (++retries > MAX_SCAN_RETRIES) {
505	<	lock();
1335	>	if (len != 0)
1336		break;
1337	+	}
1338	+	else if (f.hash < 0) {
1339	+	if ((fk = f.key) instanceof TreeBin) {
1340	+	TreeBin<V> t = (TreeBin<V>)fk;
1341	+	boolean added = false;
1342	+	t.acquire(0);
1343	+	try {
1344	+	if (tabAt(tab, i) == f) {
1345	+	len = 1;
1346	+	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1347	+	if (p != null)
1348	+	val = p.val;
1349	+	else if ((val = mf.apply(k)) != null) {
1350	+	added = true;
1351	+	len = 2;
1352	+	t.putTreeNode(h, k, val);
1353	+	}
1354	+	}
1355	+	} finally {
1356	+	t.release(0);
1357	+	}
1358	+	if (len != 0) {
1359	+	if (!added)
1360	+	return val;
1361	+	break;
1362	+	}
1363		}
1364	<	else if ((retries & 1) == 0 &&
1365	<	(f = entryForHash(this, hash)) != first) {
1366	<	e = first = f;
1367	<	retries = -1;
1364	>	else
1365	>	tab = (Node<V>[])fk;
1366	>	}
1367	>	else {
1368	>	for (Node<V> e = f; e != null; e = e.next) { // prescan
1369	>	Object ek; V ev;
1370	>	if (e.hash == h && (ev = e.val) != null &&
1371	>	((ek = e.key) == k || k.equals(ek)))
1372	>	return ev;
1373	>	}
1374	>	boolean added = false;
1375	>	synchronized (f) {
1376	>	if (tabAt(tab, i) == f) {
1377	>	len = 1;
1378	>	for (Node<V> e = f;; ++len) {
1379	>	Object ek; V ev;
1380	>	if (e.hash == h &&
1381	>	(ev = e.val) != null &&
1382	>	((ek = e.key) == k || k.equals(ek))) {
1383	>	val = ev;
1384	>	break;
1385	>	}
1386	>	Node<V> last = e;
1387	>	if ((e = e.next) == null) {
1388	>	if ((val = mf.apply(k)) != null) {
1389	>	added = true;
1390	>	last.next = new Node<V>(h, k, val, null);
1391	>	if (len >= TREE_THRESHOLD)
1392	>	replaceWithTreeBin(tab, i, k);
1393	>	}
1394	>	break;
1395	>	}
1396	>	}
1397	>	}
1398	>	}
1399	>	if (len != 0) {
1400	>	if (!added)
1401	>	return val;
1402	>	break;
1403		}
1404		}
1405		}
1406	+	if (val != null)
1407	+	addCount(1L, len);
1408	+	return val;
1409	+	}
1410
1411	<	/**
1412	<	* Remove; match on key only if value null, else match both.
1413	<	*/
1414	<	final V remove(Object key, int hash, Object value) {
1415	<	if (!tryLock())
1416	<	scanAndLock(key, hash);
1417	<	V oldValue = null;
1418	<	try {
1419	<	HashEntry<K,V>[] tab = table;
1420	<	int index = (tab.length - 1) & hash;
1421	<	HashEntry<K,V> e = entryAt(tab, index);
1422	<	HashEntry<K,V> pred = null;
1423	<	while (e != null) {
1424	<	K k;
1425	<	HashEntry<K,V> next = e.next;
1426	<	if ((k = e.key) == key ||
1427	<	(e.hash == hash && key.equals(k))) {
1428	<	V v = e.value;
1429	<	if (value == null || value == v || value.equals(v)) {
1430	<	if (pred == null)
1431	<	setEntryAt(tab, index, next);
1432	<	else
1433	<	pred.setNext(next);
1434	<	++modCount;
1435	<	--count;
1436	<	oldValue = v;
1411	>	/** Implementation for compute */
1412	>	@SuppressWarnings("unchecked") private final V internalCompute
1413	>	(K k, boolean onlyIfPresent,
1414	>	BiFunction<? super K, ? super V, ? extends V> mf) {
1415	>	if (k == null || mf == null)
1416	>	throw new NullPointerException();
1417	>	int h = spread(k.hashCode());
1418	>	V val = null;
1419	>	int delta = 0;
1420	>	int len = 0;
1421	>	for (Node<V>[] tab = table;;) {
1422	>	Node<V> f; int i, fh; Object fk;
1423	>	if (tab == null)
1424	>	tab = initTable();
1425	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1426	>	if (onlyIfPresent)
1427	>	break;
1428	>	Node<V> node = new Node<V>(h, k, null, null);
1429	>	synchronized (node) {
1430	>	if (casTabAt(tab, i, null, node)) {
1431	>	try {
1432	>	len = 1;
1433	>	if ((val = mf.apply(k, null)) != null) {
1434	>	node.val = val;
1435	>	delta = 1;
1436	>	}
1437	>	} finally {
1438	>	if (delta == 0)
1439	>	setTabAt(tab, i, null);
1440	>	}
1441	>	}
1442	>	}
1443	>	if (len != 0)
1444	>	break;
1445	>	}
1446	>	else if ((fh = f.hash) < 0) {
1447	>	if ((fk = f.key) instanceof TreeBin) {
1448	>	TreeBin<V> t = (TreeBin<V>)fk;
1449	>	t.acquire(0);
1450	>	try {
1451	>	if (tabAt(tab, i) == f) {
1452	>	len = 1;
1453	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1454	>	if (p == null && onlyIfPresent)
1455	>	break;
1456	>	V pv = (p == null) ? null : p.val;
1457	>	if ((val = mf.apply(k, pv)) != null) {
1458	>	if (p != null)
1459	>	p.val = val;
1460	>	else {
1461	>	len = 2;
1462	>	delta = 1;
1463	>	t.putTreeNode(h, k, val);
1464	>	}
1465	>	}
1466	>	else if (p != null) {
1467	>	delta = -1;
1468	>	t.deleteTreeNode(p);
1469	>	}
1470		}
1471	+	} finally {
1472	+	t.release(0);
1473	+	}
1474	+	if (len != 0)
1475		break;
1476	+	}
1477	+	else
1478	+	tab = (Node<V>[])fk;
1479	+	}
1480	+	else {
1481	+	synchronized (f) {
1482	+	if (tabAt(tab, i) == f) {
1483	+	len = 1;
1484	+	for (Node<V> e = f, pred = null;; ++len) {
1485	+	Object ek; V ev;
1486	+	if (e.hash == h &&
1487	+	(ev = e.val) != null &&
1488	+	((ek = e.key) == k || k.equals(ek))) {
1489	+	val = mf.apply(k, ev);
1490	+	if (val != null)
1491	+	e.val = val;
1492	+	else {
1493	+	delta = -1;
1494	+	Node<V> en = e.next;
1495	+	if (pred != null)
1496	+	pred.next = en;
1497	+	else
1498	+	setTabAt(tab, i, en);
1499	+	}
1500	+	break;
1501	+	}
1502	+	pred = e;
1503	+	if ((e = e.next) == null) {
1504	+	if (!onlyIfPresent &&
1505	+	(val = mf.apply(k, null)) != null) {
1506	+	pred.next = new Node<V>(h, k, val, null);
1507	+	delta = 1;
1508	+	if (len >= TREE_THRESHOLD)
1509	+	replaceWithTreeBin(tab, i, k);
1510	+	}
1511	+	break;
1512	+	}
1513	+	}
1514		}
545	–	pred = e;
546	–	e = next;
1515		}
1516	<	} finally {
1517	<	unlock();
1516	>	if (len != 0)
1517	>	break;
1518		}
551	–	return oldValue;
1519		}
1520	+	if (delta != 0)
1521	+	addCount((long)delta, len);
1522	+	return val;
1523	+	}
1524
1525	<	final boolean replace(K key, int hash, V oldValue, V newValue) {
1526	<	if (!tryLock())
1527	<	scanAndLock(key, hash);
1528	<	boolean replaced = false;
1529	<	try {
1530	<	HashEntry<K,V> e;
1531	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1532	<	K k;
1533	<	if ((k = e.key) == key ||
1534	<	(e.hash == hash && key.equals(k))) {
1535	<	if (oldValue.equals(e.value)) {
1536	<	e.value = newValue;
1537	<	++modCount;
1538	<	replaced = true;
1525	>	/** Implementation for merge */
1526	>	@SuppressWarnings("unchecked") private final V internalMerge
1527	>	(K k, V v, BiFunction<? super V, ? super V, ? extends V> mf) {
1528	>	if (k == null || v == null || mf == null)
1529	>	throw new NullPointerException();
1530	>	int h = spread(k.hashCode());
1531	>	V val = null;
1532	>	int delta = 0;
1533	>	int len = 0;
1534	>	for (Node<V>[] tab = table;;) {
1535	>	int i; Node<V> f; Object fk; V fv;
1536	>	if (tab == null)
1537	>	tab = initTable();
1538	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1539	>	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
1540	>	delta = 1;
1541	>	val = v;
1542	>	break;
1543	>	}
1544	>	}
1545	>	else if (f.hash < 0) {
1546	>	if ((fk = f.key) instanceof TreeBin) {
1547	>	TreeBin<V> t = (TreeBin<V>)fk;
1548	>	t.acquire(0);
1549	>	try {
1550	>	if (tabAt(tab, i) == f) {
1551	>	len = 1;
1552	>	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1553	>	val = (p == null) ? v : mf.apply(p.val, v);
1554	>	if (val != null) {
1555	>	if (p != null)
1556	>	p.val = val;
1557	>	else {
1558	>	len = 2;
1559	>	delta = 1;
1560	>	t.putTreeNode(h, k, val);
1561	>	}
1562	>	}
1563	>	else if (p != null) {
1564	>	delta = -1;
1565	>	t.deleteTreeNode(p);
1566	>	}
1567		}
1568	+	} finally {
1569	+	t.release(0);
1570	+	}
1571	+	if (len != 0)
1572		break;
1573	+	}
1574	+	else
1575	+	tab = (Node<V>[])fk;
1576	+	}
1577	+	else {
1578	+	synchronized (f) {
1579	+	if (tabAt(tab, i) == f) {
1580	+	len = 1;
1581	+	for (Node<V> e = f, pred = null;; ++len) {
1582	+	Object ek; V ev;
1583	+	if (e.hash == h &&
1584	+	(ev = e.val) != null &&
1585	+	((ek = e.key) == k || k.equals(ek))) {
1586	+	val = mf.apply(ev, v);
1587	+	if (val != null)
1588	+	e.val = val;
1589	+	else {
1590	+	delta = -1;
1591	+	Node<V> en = e.next;
1592	+	if (pred != null)
1593	+	pred.next = en;
1594	+	else
1595	+	setTabAt(tab, i, en);
1596	+	}
1597	+	break;
1598	+	}
1599	+	pred = e;
1600	+	if ((e = e.next) == null) {
1601	+	val = v;
1602	+	pred.next = new Node<V>(h, k, val, null);
1603	+	delta = 1;
1604	+	if (len >= TREE_THRESHOLD)
1605	+	replaceWithTreeBin(tab, i, k);
1606	+	break;
1607	+	}
1608	+	}
1609	+	}
1610	+	}
1611	+	if (len != 0)
1612	+	break;
1613	+	}
1614	+	}
1615	+	if (delta != 0)
1616	+	addCount((long)delta, len);
1617	+	return val;
1618	+	}
1619	+
1620	+	/** Implementation for putAll */
1621	+	@SuppressWarnings("unchecked") private final void internalPutAll
1622	+	(Map<? extends K, ? extends V> m) {
1623	+	tryPresize(m.size());
1624	+	long delta = 0L;     // number of uncommitted additions
1625	+	boolean npe = false; // to throw exception on exit for nulls
1626	+	try {                // to clean up counts on other exceptions
1627	+	for (Map.Entry<?, ? extends V> entry : m.entrySet()) {
1628	+	Object k; V v;
1629	+	if (entry == null || (k = entry.getKey()) == null ||
1630	+	(v = entry.getValue()) == null) {
1631	+	npe = true;
1632	+	break;
1633	+	}
1634	+	int h = spread(k.hashCode());
1635	+	for (Node<V>[] tab = table;;) {
1636	+	int i; Node<V> f; int fh; Object fk;
1637	+	if (tab == null)
1638	+	tab = initTable();
1639	+	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1640	+	if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
1641	+	++delta;
1642	+	break;
1643	+	}
1644	+	}
1645	+	else if ((fh = f.hash) < 0) {
1646	+	if ((fk = f.key) instanceof TreeBin) {
1647	+	TreeBin<V> t = (TreeBin<V>)fk;
1648	+	boolean validated = false;
1649	+	t.acquire(0);
1650	+	try {
1651	+	if (tabAt(tab, i) == f) {
1652	+	validated = true;
1653	+	TreeNode<V> p = t.getTreeNode(h, k, t.root);
1654	+	if (p != null)
1655	+	p.val = v;
1656	+	else {
1657	+	t.putTreeNode(h, k, v);
1658	+	++delta;
1659	+	}
1660	+	}
1661	+	} finally {
1662	+	t.release(0);
1663	+	}
1664	+	if (validated)
1665	+	break;
1666	+	}
1667	+	else
1668	+	tab = (Node<V>[])fk;
1669	+	}
1670	+	else {
1671	+	int len = 0;
1672	+	synchronized (f) {
1673	+	if (tabAt(tab, i) == f) {
1674	+	len = 1;
1675	+	for (Node<V> e = f;; ++len) {
1676	+	Object ek; V ev;
1677	+	if (e.hash == h &&
1678	+	(ev = e.val) != null &&
1679	+	((ek = e.key) == k || k.equals(ek))) {
1680	+	e.val = v;
1681	+	break;
1682	+	}
1683	+	Node<V> last = e;
1684	+	if ((e = e.next) == null) {
1685	+	++delta;
1686	+	last.next = new Node<V>(h, k, v, null);
1687	+	if (len >= TREE_THRESHOLD)
1688	+	replaceWithTreeBin(tab, i, k);
1689	+	break;
1690	+	}
1691	+	}
1692	+	}
1693	+	}
1694	+	if (len != 0) {
1695	+	if (len > 1)
1696	+	addCount(delta, len);
1697	+	break;
1698	+	}
1699	+	}
1700	+	}
1701	+	}
1702	+	} finally {
1703	+	if (delta != 0L)
1704	+	addCount(delta, 2);
1705	+	}
1706	+	if (npe)
1707	+	throw new NullPointerException();
1708	+	}
1709	+
1710	+	/**
1711	+	* Implementation for clear. Steps through each bin, removing all
1712	+	* nodes.
1713	+	*/
1714	+	@SuppressWarnings("unchecked") private final void internalClear() {
1715	+	long delta = 0L; // negative number of deletions
1716	+	int i = 0;
1717	+	Node<V>[] tab = table;
1718	+	while (tab != null && i < tab.length) {
1719	+	Node<V> f = tabAt(tab, i);
1720	+	if (f == null)
1721	+	++i;
1722	+	else if (f.hash < 0) {
1723	+	Object fk;
1724	+	if ((fk = f.key) instanceof TreeBin) {
1725	+	TreeBin<V> t = (TreeBin<V>)fk;
1726	+	t.acquire(0);
1727	+	try {
1728	+	if (tabAt(tab, i) == f) {
1729	+	for (Node<V> p = t.first; p != null; p = p.next) {
1730	+	if (p.val != null) { // (currently always true)
1731	+	p.val = null;
1732	+	--delta;
1733	+	}
1734	+	}
1735	+	t.first = null;
1736	+	t.root = null;
1737	+	++i;
1738	+	}
1739	+	} finally {
1740	+	t.release(0);
1741	+	}
1742	+	}
1743	+	else
1744	+	tab = (Node<V>[])fk;
1745	+	}
1746	+	else {
1747	+	synchronized (f) {
1748	+	if (tabAt(tab, i) == f) {
1749	+	for (Node<V> e = f; e != null; e = e.next) {
1750	+	if (e.val != null) {  // (currently always true)
1751	+	e.val = null;
1752	+	--delta;
1753	+	}
1754	+	}
1755	+	setTabAt(tab, i, null);
1756	+	++i;
1757		}
1758		}
572	–	} finally {
573	–	unlock();
1759		}
575	–	return replaced;
1760		}
1761	+	if (delta != 0L)
1762	+	addCount(delta, -1);
1763	+	}
1764
1765	<	final V replace(K key, int hash, V value) {
1766	<	if (!tryLock())
1767	<	scanAndLock(key, hash);
1768	<	V oldValue = null;
1769	<	try {
1770	<	HashEntry<K,V> e;
1771	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1772	<	K k;
1773	<	if ((k = e.key) == key ||
1774	<	(e.hash == hash && key.equals(k))) {
1775	<	oldValue = e.value;
1776	<	e.value = value;
1777	<	++modCount;
1765	>	/* ---------------- Table Initialization and Resizing -------------- */
1766	>
1767	>	/**
1768	>	* Returns a power of two table size for the given desired capacity.
1769	>	* See Hackers Delight, sec 3.2
1770	>	*/
1771	>	private static final int tableSizeFor(int c) {
1772	>	int n = c - 1;
1773	>	n |= n >>> 1;
1774	>	n |= n >>> 2;
1775	>	n |= n >>> 4;
1776	>	n |= n >>> 8;
1777	>	n |= n >>> 16;
1778	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1779	>	}
1780	>
1781	>	/**
1782	>	* Initializes table, using the size recorded in sizeCtl.
1783	>	*/
1784	>	@SuppressWarnings("unchecked") private final Node<V>[] initTable() {
1785	>	Node<V>[] tab; int sc;
1786	>	while ((tab = table) == null) {
1787	>	if ((sc = sizeCtl) < 0)
1788	>	Thread.yield(); // lost initialization race; just spin
1789	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1790	>	try {
1791	>	if ((tab = table) == null) {
1792	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1793	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n];
1794	>	table = tab = (Node<V>[])tb;
1795	>	sc = n - (n >>> 2);
1796	>	}
1797	>	} finally {
1798	>	sizeCtl = sc;
1799	>	}
1800	>	break;
1801	>	}
1802	>	}
1803	>	return tab;
1804	>	}
1805	>
1806	>	/**
1807	>	* Adds to count, and if table is too small and not already
1808	>	* resizing, initiates transfer. If already resizing, helps
1809	>	* perform transfer if work is available.  Rechecks occupancy
1810	>	* after a transfer to see if another resize is already needed
1811	>	* because resizings are lagging additions.
1812	>	*
1813	>	* @param x the count to add
1814	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
1815	>	*/
1816	>	private final void addCount(long x, int check) {
1817	>	Cell[] as; long b, s;
1818	>	if ((as = counterCells) != null ||
1819	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
1820	>	Cell a; long v; int m;
1821	>	boolean uncontended = true;
1822	>	if (as == null || (m = as.length - 1) < 0 ||
1823	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
1824	>	!(uncontended =
1825	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
1826	>	fullAddCount(x, uncontended);
1827	>	return;
1828	>	}
1829	>	if (check <= 1)
1830	>	return;
1831	>	s = sumCount();
1832	>	}
1833	>	if (check >= 0) {
1834	>	Node<V>[] tab, nt; int sc;
1835	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
1836	>	tab.length < MAXIMUM_CAPACITY) {
1837	>	if (sc < 0) {
1838	>	if (sc == -1 || transferIndex <= transferOrigin ||
1839	>	(nt = nextTable) == null)
1840		break;
1841	+	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
1842	+	transfer(tab, nt);
1843	+	}
1844	+	else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
1845	+	transfer(tab, null);
1846	+	s = sumCount();
1847	+	}
1848	+	}
1849	+	}
1850	+
1851	+	/**
1852	+	* Tries to presize table to accommodate the given number of elements.
1853	+	*
1854	+	* @param size number of elements (doesn't need to be perfectly accurate)
1855	+	*/
1856	+	@SuppressWarnings("unchecked") private final void tryPresize(int size) {
1857	+	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1858	+	tableSizeFor(size + (size >>> 1) + 1);
1859	+	int sc;
1860	+	while ((sc = sizeCtl) >= 0) {
1861	+	Node<V>[] tab = table; int n;
1862	+	if (tab == null || (n = tab.length) == 0) {
1863	+	n = (sc > c) ? sc : c;
1864	+	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1865	+	try {
1866	+	if (table == tab) {
1867	+	@SuppressWarnings("rawtypes") Node[] tb = new Node[n];
1868	+	table = (Node<V>[])tb;
1869	+	sc = n - (n >>> 2);
1870	+	}
1871	+	} finally {
1872	+	sizeCtl = sc;
1873		}
1874		}
594	–	} finally {
595	–	unlock();
1875		}
1876	<	return oldValue;
1876	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1877	>	break;
1878	>	else if (tab == table &&
1879	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
1880	>	transfer(tab, null);
1881		}
1882	+	}
1883
1884	<	final void clear() {
1885	<	lock();
1884	>	/*
1885	>	* Moves and/or copies the nodes in each bin to new table. See
1886	>	* above for explanation.
1887	>	*/
1888	>	@SuppressWarnings("unchecked") private final void transfer
1889	>	(Node<V>[] tab, Node<V>[] nextTab) {
1890	>	int n = tab.length, stride;
1891	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
1892	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
1893	>	if (nextTab == null) {            // initiating
1894		try {
1895	<	HashEntry<K,V>[] tab = table;
1896	<	for (int i = 0; i < tab.length ; i++)
1897	<	setEntryAt(tab, i, null);
1898	<	++modCount;
1899	<	count = 0;
1900	<	} finally {
1901	<	unlock();
1895	>	@SuppressWarnings("rawtypes") Node[] tb = new Node[n << 1];
1896	>	nextTab = (Node<V>[])tb;
1897	>	} catch (Throwable ex) {      // try to cope with OOME
1898	>	sizeCtl = Integer.MAX_VALUE;
1899	>	return;
1900	>	}
1901	>	nextTable = nextTab;
1902	>	transferOrigin = n;
1903	>	transferIndex = n;
1904	>	Node<V> rev = new Node<V>(MOVED, tab, null, null);
1905	>	for (int k = n; k > 0;) {    // progressively reveal ready slots
1906	>	int nextk = (k > stride) ? k - stride : 0;
1907	>	for (int m = nextk; m < k; ++m)
1908	>	nextTab[m] = rev;
1909	>	for (int m = n + nextk; m < n + k; ++m)
1910	>	nextTab[m] = rev;
1911	>	U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
1912		}
1913		}
1914	+	int nextn = nextTab.length;
1915	+	Node<V> fwd = new Node<V>(MOVED, nextTab, null, null);
1916	+	boolean advance = true;
1917	+	for (int i = 0, bound = 0;;) {
1918	+	int nextIndex, nextBound; Node<V> f; Object fk;
1919	+	while (advance) {
1920	+	if (--i >= bound)
1921	+	advance = false;
1922	+	else if ((nextIndex = transferIndex) <= transferOrigin) {
1923	+	i = -1;
1924	+	advance = false;
1925	+	}
1926	+	else if (U.compareAndSwapInt
1927	+	(this, TRANSFERINDEX, nextIndex,
1928	+	nextBound = (nextIndex > stride ?
1929	+	nextIndex - stride : 0))) {
1930	+	bound = nextBound;
1931	+	i = nextIndex - 1;
1932	+	advance = false;
1933	+	}
1934	+	}
1935	+	if (i < 0 || i >= n || i + n >= nextn) {
1936	+	for (int sc;;) {
1937	+	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
1938	+	if (sc == -1) {
1939	+	nextTable = null;
1940	+	table = nextTab;
1941	+	sizeCtl = (n << 1) - (n >>> 1);
1942	+	}
1943	+	return;
1944	+	}
1945	+	}
1946	+	}
1947	+	else if ((f = tabAt(tab, i)) == null) {
1948	+	if (casTabAt(tab, i, null, fwd)) {
1949	+	setTabAt(nextTab, i, null);
1950	+	setTabAt(nextTab, i + n, null);
1951	+	advance = true;
1952	+	}
1953	+	}
1954	+	else if (f.hash >= 0) {
1955	+	synchronized (f) {
1956	+	if (tabAt(tab, i) == f) {
1957	+	int runBit = f.hash & n;
1958	+	Node<V> lastRun = f, lo = null, hi = null;
1959	+	for (Node<V> p = f.next; p != null; p = p.next) {
1960	+	int b = p.hash & n;
1961	+	if (b != runBit) {
1962	+	runBit = b;
1963	+	lastRun = p;
1964	+	}
1965	+	}
1966	+	if (runBit == 0)
1967	+	lo = lastRun;
1968	+	else
1969	+	hi = lastRun;
1970	+	for (Node<V> p = f; p != lastRun; p = p.next) {
1971	+	int ph = p.hash;
1972	+	Object pk = p.key; V pv = p.val;
1973	+	if ((ph & n) == 0)
1974	+	lo = new Node<V>(ph, pk, pv, lo);
1975	+	else
1976	+	hi = new Node<V>(ph, pk, pv, hi);
1977	+	}
1978	+	setTabAt(nextTab, i, lo);
1979	+	setTabAt(nextTab, i + n, hi);
1980	+	setTabAt(tab, i, fwd);
1981	+	advance = true;
1982	+	}
1983	+	}
1984	+	}
1985	+	else if ((fk = f.key) instanceof TreeBin) {
1986	+	TreeBin<V> t = (TreeBin<V>)fk;
1987	+	t.acquire(0);
1988	+	try {
1989	+	if (tabAt(tab, i) == f) {
1990	+	TreeBin<V> lt = new TreeBin<V>();
1991	+	TreeBin<V> ht = new TreeBin<V>();
1992	+	int lc = 0, hc = 0;
1993	+	for (Node<V> e = t.first; e != null; e = e.next) {
1994	+	int h = e.hash;
1995	+	Object k = e.key; V v = e.val;
1996	+	if ((h & n) == 0) {
1997	+	++lc;
1998	+	lt.putTreeNode(h, k, v);
1999	+	}
2000	+	else {
2001	+	++hc;
2002	+	ht.putTreeNode(h, k, v);
2003	+	}
2004	+	}
2005	+	Node<V> ln, hn; // throw away trees if too small
2006	+	if (lc < TREE_THRESHOLD) {
2007	+	ln = null;
2008	+	for (Node<V> p = lt.first; p != null; p = p.next)
2009	+	ln = new Node<V>(p.hash, p.key, p.val, ln);
2010	+	}
2011	+	else
2012	+	ln = new Node<V>(MOVED, lt, null, null);
2013	+	setTabAt(nextTab, i, ln);
2014	+	if (hc < TREE_THRESHOLD) {
2015	+	hn = null;
2016	+	for (Node<V> p = ht.first; p != null; p = p.next)
2017	+	hn = new Node<V>(p.hash, p.key, p.val, hn);
2018	+	}
2019	+	else
2020	+	hn = new Node<V>(MOVED, ht, null, null);
2021	+	setTabAt(nextTab, i + n, hn);
2022	+	setTabAt(tab, i, fwd);
2023	+	advance = true;
2024	+	}
2025	+	} finally {
2026	+	t.release(0);
2027	+	}
2028	+	}
2029	+	else
2030	+	advance = true; // already processed
2031	+	}
2032		}
2033
2034	<	// Accessing segments
2035	<
2036	<	/**
2037	<	* Gets the jth element of given segment array (if nonnull) with
2038	<	* volatile element access semantics via Unsafe. (The null check
2039	<	* can trigger harmlessly only during deserialization.) Note:
2040	<	* because each element of segments array is set only once (using
2041	<	* fully ordered writes), some performance-sensitive methods rely
2042	<	* on this method only as a recheck upon null reads.
2043	<	*/
2044	<	@SuppressWarnings("unchecked")
2045	<	static final <K,V> Segment<K,V> segmentAt(Segment<K,V>[] ss, int j) {
626	<	long u = (j << SSHIFT) + SBASE;
627	<	return ss == null ? null :
628	<	(Segment<K,V>) UNSAFE.getObjectVolatile(ss, u);
2034	>	/* ---------------- Counter support -------------- */
2035	>
2036	>	final long sumCount() {
2037	>	Cell[] as = counterCells; Cell a;
2038	>	long sum = baseCount;
2039	>	if (as != null) {
2040	>	for (int i = 0; i < as.length; ++i) {
2041	>	if ((a = as[i]) != null)
2042	>	sum += a.value;
2043	>	}
2044	>	}
2045	>	return sum;
2046		}
2047
2048	+	// See LongAdder version for explanation
2049	+	private final void fullAddCount(long x, boolean wasUncontended) {
2050	+	int h;
2051	+	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2052	+	ThreadLocalRandom.localInit();      // force initialization
2053	+	h = ThreadLocalRandom.getProbe();
2054	+	wasUncontended = true;
2055	+	}
2056	+	boolean collide = false;                // True if last slot nonempty
2057	+	for (;;) {
2058	+	Cell[] as; Cell a; int n; long v;
2059	+	if ((as = counterCells) != null && (n = as.length) > 0) {
2060	+	if ((a = as[(n - 1) & h]) == null) {
2061	+	if (cellsBusy == 0) {            // Try to attach new Cell
2062	+	Cell r = new Cell(x); // Optimistic create
2063	+	if (cellsBusy == 0 &&
2064	+	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2065	+	boolean created = false;
2066	+	try {               // Recheck under lock
2067	+	Cell[] rs; int m, j;
2068	+	if ((rs = counterCells) != null &&
2069	+	(m = rs.length) > 0 &&
2070	+	rs[j = (m - 1) & h] == null) {
2071	+	rs[j] = r;
2072	+	created = true;
2073	+	}
2074	+	} finally {
2075	+	cellsBusy = 0;
2076	+	}
2077	+	if (created)
2078	+	break;
2079	+	continue;           // Slot is now non-empty
2080	+	}
2081	+	}
2082	+	collide = false;
2083	+	}
2084	+	else if (!wasUncontended)       // CAS already known to fail
2085	+	wasUncontended = true;      // Continue after rehash
2086	+	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2087	+	break;
2088	+	else if (counterCells != as || n >= NCPU)
2089	+	collide = false;            // At max size or stale
2090	+	else if (!collide)
2091	+	collide = true;
2092	+	else if (cellsBusy == 0 &&
2093	+	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2094	+	try {
2095	+	if (counterCells == as) {// Expand table unless stale
2096	+	Cell[] rs = new Cell[n << 1];
2097	+	for (int i = 0; i < n; ++i)
2098	+	rs[i] = as[i];
2099	+	counterCells = rs;
2100	+	}
2101	+	} finally {
2102	+	cellsBusy = 0;
2103	+	}
2104	+	collide = false;
2105	+	continue;                   // Retry with expanded table
2106	+	}
2107	+	h = ThreadLocalRandom.advanceProbe(h);
2108	+	}
2109	+	else if (cellsBusy == 0 && counterCells == as &&
2110	+	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2111	+	boolean init = false;
2112	+	try {                           // Initialize table
2113	+	if (counterCells == as) {
2114	+	Cell[] rs = new Cell[2];
2115	+	rs[h & 1] = new Cell(x);
2116	+	counterCells = rs;
2117	+	init = true;
2118	+	}
2119	+	} finally {
2120	+	cellsBusy = 0;
2121	+	}
2122	+	if (init)
2123	+	break;
2124	+	}
2125	+	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2126	+	break;                          // Fall back on using base
2127	+	}
2128	+	}
2129	+
2130	+	/* ----------------Table Traversal -------------- */
2131	+
2132		/**
2133	<	* Returns the segment for the given index, creating it and
2134	<	* recording in segment table (via CAS) if not already present.
2135	<	*
2136	<	* @param k the index
2137	<	* @return the segment
2138	<	*/
2139	<	@SuppressWarnings("unchecked")
2140	<	private Segment<K,V> ensureSegment(int k) {
2141	<	final Segment<K,V>[] ss = this.segments;
2142	<	long u = (k << SSHIFT) + SBASE; // raw offset
2143	<	Segment<K,V> seg;
2144	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u)) == null) {
2145	<	Segment<K,V> proto = ss[0]; // use segment 0 as prototype
2146	<	int cap = proto.table.length;
2147	<	float lf = proto.loadFactor;
2148	<	int threshold = (int)(cap * lf);
2149	<	HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry<?,?>[cap];
2150	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
2151	<	== null) { // recheck
2152	<	Segment<K,V> s = new Segment<K,V>(lf, threshold, tab);
2153	<	while ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
2154	<	== null) {
2155	<	if (UNSAFE.compareAndSwapObject(ss, u, null, seg = s))
2156	<	break;
2133	>	* Encapsulates traversal for methods such as containsValue; also
2134	>	* serves as a base class for other iterators and bulk tasks.
2135	>	*
2136	>	* At each step, the iterator snapshots the key ("nextKey") and
2137	>	* value ("nextVal") of a valid node (i.e., one that, at point of
2138	>	* snapshot, has a non-null user value). Because val fields can
2139	>	* change (including to null, indicating deletion), field nextVal
2140	>	* might not be accurate at point of use, but still maintains the
2141	>	* weak consistency property of holding a value that was once
2142	>	* valid. To support iterator.remove, the nextKey field is not
2143	>	* updated (nulled out) when the iterator cannot advance.
2144	>	*
2145	>	* Internal traversals directly access these fields, as in:
2146	>	* {@code while (it.advance() != null) { process(it.nextKey); }}
2147	>	*
2148	>	* Exported iterators must track whether the iterator has advanced
2149	>	* (in hasNext vs next) (by setting/checking/nulling field
2150	>	* nextVal), and then extract key, value, or key-value pairs as
2151	>	* return values of next().
2152	>	*
2153	>	* The iterator visits once each still-valid node that was
2154	>	* reachable upon iterator construction. It might miss some that
2155	>	* were added to a bin after the bin was visited, which is OK wrt
2156	>	* consistency guarantees. Maintaining this property in the face
2157	>	* of possible ongoing resizes requires a fair amount of
2158	>	* bookkeeping state that is difficult to optimize away amidst
2159	>	* volatile accesses.  Even so, traversal maintains reasonable
2160	>	* throughput.
2161	>	*
2162	>	* Normally, iteration proceeds bin-by-bin traversing lists.
2163	>	* However, if the table has been resized, then all future steps
2164	>	* must traverse both the bin at the current index as well as at
2165	>	* (index + baseSize); and so on for further resizings. To
2166	>	* paranoically cope with potential sharing by users of iterators
2167	>	* across threads, iteration terminates if a bounds checks fails
2168	>	* for a table read.
2169	>	*
2170	>	* This class supports both Spliterator-based traversal and
2171	>	* CountedCompleter-based bulk tasks. The same "batch" field is
2172	>	* used, but in slightly different ways, in the two cases.  For
2173	>	* Spliterators, it is a saturating (at Integer.MAX_VALUE)
2174	>	* estimate of element coverage. For CHM tasks, it is a pre-scaled
2175	>	* size that halves down to zero for leaf tasks, that is only
2176	>	* computed upon execution of the task. (Tasks can be submitted to
2177	>	* any pool, of any size, so we don't know scale factors until
2178	>	* running.)
2179	>	*
2180	>	* This class extends CountedCompleter to streamline parallel
2181	>	* iteration in bulk operations. This adds only a few fields of
2182	>	* space overhead, which is small enough in cases where it is not
2183	>	* needed to not worry about it.  Because CountedCompleter is
2184	>	* Serializable, but iterators need not be, we need to add warning
2185	>	* suppressions.
2186	>	*/
2187	>	@SuppressWarnings("serial") static class Traverser<K,V,R>
2188	>	extends CountedCompleter<R> {
2189	>	final ConcurrentHashMap<K, V> map;
2190	>	Node<V> next;        // the next entry to use
2191	>	Object nextKey;      // cached key field of next
2192	>	V nextVal;           // cached val field of next
2193	>	Node<V>[] tab;       // current table; updated if resized
2194	>	int index;           // index of bin to use next
2195	>	int baseIndex;       // current index of initial table
2196	>	int baseLimit;       // index bound for initial table
2197	>	int baseSize;        // initial table size
2198	>	int batch;           // split control
2199	>	/** Creates iterator for all entries in the table. */
2200	>	Traverser(ConcurrentHashMap<K, V> map) {
2201	>	this.map = map;
2202	>	Node<V>[] t;
2203	>	if ((t = tab = map.table) != null)
2204	>	baseLimit = baseSize = t.length;
2205	>	}
2206	>
2207	>	/** Task constructor */
2208	>	Traverser(ConcurrentHashMap<K,V> map, Traverser<K,V,?> it, int batch) {
2209	>	super(it);
2210	>	this.map = map;
2211	>	this.batch = batch; // -1 if unknown
2212	>	if (it == null) {
2213	>	Node<V>[] t;
2214	>	if ((t = tab = map.table) != null)
2215	>	baseLimit = baseSize = t.length;
2216	>	}
2217	>	else { // split parent
2218	>	this.tab = it.tab;
2219	>	this.baseSize = it.baseSize;
2220	>	int hi = this.baseLimit = it.baseLimit;
2221	>	it.baseLimit = this.index = this.baseIndex =
2222	>	(hi + it.baseIndex + 1) >>> 1;
2223	>	}
2224	>	}
2225	>
2226	>	/** Spliterator constructor */
2227	>	Traverser(ConcurrentHashMap<K,V> map, Traverser<K,V,?> it) {
2228	>	super(it);
2229	>	this.map = map;
2230	>	if (it == null) {
2231	>	Node<V>[] t;
2232	>	if ((t = tab = map.table) != null)
2233	>	baseLimit = baseSize = t.length;
2234	>	long n = map.sumCount();
2235	>	batch = ((n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2236	>	(int)n);
2237	>	}
2238	>	else {
2239	>	this.tab = it.tab;
2240	>	this.baseSize = it.baseSize;
2241	>	int hi = this.baseLimit = it.baseLimit;
2242	>	it.baseLimit = this.index = this.baseIndex =
2243	>	(hi + it.baseIndex + 1) >>> 1;
2244	>	this.batch = it.batch >>>= 1;
2245	>	}
2246	>	}
2247	>
2248	>	/**
2249	>	* Advances next; returns nextVal or null if terminated.
2250	>	* See above for explanation.
2251	>	*/
2252	>	@SuppressWarnings("unchecked") final V advance() {
2253	>	Node<V> e = next;
2254	>	V ev = null;
2255	>	outer: do {
2256	>	if (e != null)                  // advance past used/skipped node
2257	>	e = e.next;
2258	>	while (e == null) {             // get to next non-null bin
2259	>	ConcurrentHashMap<K, V> m;
2260	>	Node<V>[] t; int b, i, n; Object ek; //  must use locals
2261	>	if ((t = tab) != null)
2262	>	n = t.length;
2263	>	else if ((m = map) != null && (t = tab = m.table) != null)
2264	>	n = baseLimit = baseSize = t.length;
2265	>	else
2266	>	break outer;
2267	>	if ((b = baseIndex) >= baseLimit ||
2268	>	(i = index) < 0 || i >= n)
2269	>	break outer;
2270	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
2271	>	if ((ek = e.key) instanceof TreeBin)
2272	>	e = ((TreeBin<V>)ek).first;
2273	>	else {
2274	>	tab = (Node<V>[])ek;
2275	>	continue;           // restarts due to null val
2276	>	}
2277	>	}                           // visit upper slots if present
2278	>	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2279		}
2280	+	nextKey = e.key;
2281	+	} while ((ev = e.val) == null);    // skip deleted or special nodes
2282	+	next = e;
2283	+	return nextVal = ev;
2284	+	}
2285	+
2286	+	public final void remove() {
2287	+	Object k = nextKey;
2288	+	if (k == null && (advance() == null || (k = nextKey) == null))
2289	+	throw new IllegalStateException();
2290	+	map.internalReplace(k, null, null);
2291	+	}
2292	+
2293	+	public final boolean hasNext() {
2294	+	return nextVal != null || advance() != null;
2295	+	}
2296	+
2297	+	public final boolean hasMoreElements() { return hasNext(); }
2298	+
2299	+	public void compute() { } // default no-op CountedCompleter body
2300	+
2301	+	/**
2302	+	* Returns a batch value > 0 if this task should (and must) be
2303	+	* split, if so, adding to pending count, and in any case
2304	+	* updating batch value. The initial batch value is approx
2305	+	* exp2 of the number of times (minus one) to split task by
2306	+	* two before executing leaf action. This value is faster to
2307	+	* compute and more convenient to use as a guide to splitting
2308	+	* than is the depth, since it is used while dividing by two
2309	+	* anyway.
2310	+	*/
2311	+	final int preSplit() {
2312	+	int b;  ForkJoinPool pool;
2313	+	if ((b = batch) < 0) { // force initialization
2314	+	int sp = (((pool = getPool()) == null) ?
2315	+	ForkJoinPool.getCommonPoolParallelism() :
2316	+	pool.getParallelism()) << 3; // slack of 8
2317	+	long n = map.sumCount();
2318	+	b = (n <= 0L) ? 0 : (n < (long)sp) ? (int)n : sp;
2319		}
2320	+	b = (b <= 1 || baseIndex == baseLimit) ? 0 : (b >>> 1);
2321	+	if ((batch = b) > 0)
2322	+	addToPendingCount(1);
2323	+	return b;
2324	+	}
2325	+
2326	+	// spliterator support
2327	+
2328	+	public boolean hasExactSize() {
2329	+	return false;
2330	+	}
2331	+
2332	+	public boolean hasExactSplits() {
2333	+	return false;
2334	+	}
2335	+
2336	+	public long estimateSize() {
2337	+	return batch;
2338		}
659	–	return seg;
2339		}
2340
2341	<	// Hash-based segment and entry accesses
2341	>	/* ---------------- Public operations -------------- */
2342
2343		/**
2344	<	* Gets the segment for the given hash code.
2344	>	* Creates a new, empty map with the default initial table size (16).
2345		*/
2346	<	@SuppressWarnings("unchecked")
668	<	private Segment<K,V> segmentForHash(int h) {
669	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
670	<	return (Segment<K,V>) UNSAFE.getObjectVolatile(segments, u);
2346	>	public ConcurrentHashMap() {
2347		}
2348
2349		/**
2350	<	* Gets the table entry for the given segment and hash code.
2350	>	* Creates a new, empty map with an initial table size
2351	>	* accommodating the specified number of elements without the need
2352	>	* to dynamically resize.
2353	>	*
2354	>	* @param initialCapacity The implementation performs internal
2355	>	* sizing to accommodate this many elements.
2356	>	* @throws IllegalArgumentException if the initial capacity of
2357	>	* elements is negative
2358		*/
2359	<	@SuppressWarnings("unchecked")
2360	<	static final <K,V> HashEntry<K,V> entryForHash(Segment<K,V> seg, int h) {
2361	<	HashEntry<K,V>[] tab;
2362	<	return (seg == null || (tab = seg.table) == null) ? null :
2363	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
2364	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
2359	>	public ConcurrentHashMap(int initialCapacity) {
2360	>	if (initialCapacity < 0)
2361	>	throw new IllegalArgumentException();
2362	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2363	>	MAXIMUM_CAPACITY :
2364	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2365	>	this.sizeCtl = cap;
2366		}
2367
684	–	/* ---------------- Public operations -------------- */
685	–
2368		/**
2369	<	* Creates a new, empty map with the specified initial
688	<	* capacity, load factor and concurrency level.
2369	>	* Creates a new map with the same mappings as the given map.
2370		*
2371	<	* @param initialCapacity the initial capacity. The implementation
691	<	* performs internal sizing to accommodate this many elements.
692	<	* @param loadFactor  the load factor threshold, used to control resizing.
693	<	* Resizing may be performed when the average number of elements per
694	<	* bin exceeds this threshold.
695	<	* @param concurrencyLevel the estimated number of concurrently
696	<	* updating threads. The implementation performs internal sizing
697	<	* to try to accommodate this many threads.
698	<	* @throws IllegalArgumentException if the initial capacity is
699	<	* negative or the load factor or concurrencyLevel are
700	<	* nonpositive.
2371	>	* @param m the map
2372		*/
2373	<	@SuppressWarnings("unchecked")
2374	<	public ConcurrentHashMap(int initialCapacity,
2375	<	float loadFactor, int concurrencyLevel) {
705	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
706	<	throw new IllegalArgumentException();
707	<	if (concurrencyLevel > MAX_SEGMENTS)
708	<	concurrencyLevel = MAX_SEGMENTS;
709	<	// Find power-of-two sizes best matching arguments
710	<	int sshift = 0;
711	<	int ssize = 1;
712	<	while (ssize < concurrencyLevel) {
713	<	++sshift;
714	<	ssize <<= 1;
715	<	}
716	<	this.segmentShift = 32 - sshift;
717	<	this.segmentMask = ssize - 1;
718	<	if (initialCapacity > MAXIMUM_CAPACITY)
719	<	initialCapacity = MAXIMUM_CAPACITY;
720	<	int c = initialCapacity / ssize;
721	<	if (c * ssize < initialCapacity)
722	<	++c;
723	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
724	<	while (cap < c)
725	<	cap <<= 1;
726	<	// create segments and segments[0]
727	<	Segment<K,V> s0 =
728	<	new Segment<K,V>(loadFactor, (int)(cap * loadFactor),
729	<	(HashEntry<K,V>[])new HashEntry<?,?>[cap]);
730	<	Segment<K,V>[] ss = (Segment<K,V>[])new Segment<?,?>[ssize];
731	<	UNSAFE.putOrderedObject(ss, SBASE, s0); // ordered write of segments[0]
732	<	this.segments = ss;
2373	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2374	>	this.sizeCtl = DEFAULT_CAPACITY;
2375	>	internalPutAll(m);
2376		}
2377
2378		/**
2379	<	* Creates a new, empty map with the specified initial capacity
2380	<	* and load factor and with the default concurrencyLevel (16).
2379	>	* Creates a new, empty map with an initial table size based on
2380	>	* the given number of elements ({@code initialCapacity}) and
2381	>	* initial table density ({@code loadFactor}).
2382		*
2383	<	* @param initialCapacity The implementation performs internal
2384	<	* sizing to accommodate this many elements.
2385	<	* @param loadFactor  the load factor threshold, used to control resizing.
2386	<	* Resizing may be performed when the average number of elements per
2387	<	* bin exceeds this threshold.
2383	>	* @param initialCapacity the initial capacity. The implementation
2384	>	* performs internal sizing to accommodate this many elements,
2385	>	* given the specified load factor.
2386	>	* @param loadFactor the load factor (table density) for
2387	>	* establishing the initial table size
2388		* @throws IllegalArgumentException if the initial capacity of
2389		* elements is negative or the load factor is nonpositive
2390		*
2391		* @since 1.6
2392		*/
2393		public ConcurrentHashMap(int initialCapacity, float loadFactor) {
2394	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2394	>	this(initialCapacity, loadFactor, 1);
2395		}
2396
2397		/**
2398	<	* Creates a new, empty map with the specified initial capacity,
2399	<	* and with default load factor (0.75) and concurrencyLevel (16).
2398	>	* Creates a new, empty map with an initial table size based on
2399	>	* the given number of elements ({@code initialCapacity}), table
2400	>	* density ({@code loadFactor}), and number of concurrently
2401	>	* updating threads ({@code concurrencyLevel}).
2402		*
2403		* @param initialCapacity the initial capacity. The implementation
2404	<	* performs internal sizing to accommodate this many elements.
2405	<	* @throws IllegalArgumentException if the initial capacity of
2406	<	* elements is negative.
2404	>	* performs internal sizing to accommodate this many elements,
2405	>	* given the specified load factor.
2406	>	* @param loadFactor the load factor (table density) for
2407	>	* establishing the initial table size
2408	>	* @param concurrencyLevel the estimated number of concurrently
2409	>	* updating threads. The implementation may use this value as
2410	>	* a sizing hint.
2411	>	* @throws IllegalArgumentException if the initial capacity is
2412	>	* negative or the load factor or concurrencyLevel are
2413	>	* nonpositive
2414		*/
2415	<	public ConcurrentHashMap(int initialCapacity) {
2416	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2415	>	public ConcurrentHashMap(int initialCapacity,
2416	>	float loadFactor, int concurrencyLevel) {
2417	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2418	>	throw new IllegalArgumentException();
2419	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2420	>	initialCapacity = concurrencyLevel;   // as estimated threads
2421	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2422	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
2423	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
2424	>	this.sizeCtl = cap;
2425		}
2426
2427		/**
2428	<	* Creates a new, empty map with a default initial capacity (16),
2429	<	* load factor (0.75) and concurrencyLevel (16).
2428	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2429	>	* from the given type to {@code Boolean.TRUE}.
2430	>	*
2431	>	* @return the new set
2432		*/
2433	<	public ConcurrentHashMap() {
2434	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2433	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2434	>	return new KeySetView<K,Boolean>(new ConcurrentHashMap<K,Boolean>(),
2435	>	Boolean.TRUE);
2436		}
2437
2438		/**
2439	<	* Creates a new map with the same mappings as the given map.
2440	<	* The map is created with a capacity of 1.5 times the number
777	<	* of mappings in the given map or 16 (whichever is greater),
778	<	* and a default load factor (0.75) and concurrencyLevel (16).
2439	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2440	>	* from the given type to {@code Boolean.TRUE}.
2441		*
2442	<	* @param m the map
2442	>	* @param initialCapacity The implementation performs internal
2443	>	* sizing to accommodate this many elements.
2444	>	* @throws IllegalArgumentException if the initial capacity of
2445	>	* elements is negative
2446	>	* @return the new set
2447		*/
2448	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2449	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
2450	<	DEFAULT_INITIAL_CAPACITY),
785	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
786	<	putAll(m);
2448	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2449	>	return new KeySetView<K,Boolean>
2450	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2451		}
2452
2453		/**
2454	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
791	<	*
792	<	* @return <tt>true</tt> if this map contains no key-value mappings
2454	>	* {@inheritDoc}
2455		*/
2456		public boolean isEmpty() {
2457	<	/*
796	<	* Sum per-segment modCounts to avoid mis-reporting when
797	<	* elements are concurrently added and removed in one segment
798	<	* while checking another, in which case the table was never
799	<	* actually empty at any point. (The sum ensures accuracy up
800	<	* through at least 1<<31 per-segment modifications before
801	<	* recheck.)  Methods size() and containsValue() use similar
802	<	* constructions for stability checks.
803	<	*/
804	<	long sum = 0L;
805	<	final Segment<K,V>[] segments = this.segments;
806	<	for (int j = 0; j < segments.length; ++j) {
807	<	Segment<K,V> seg = segmentAt(segments, j);
808	<	if (seg != null) {
809	<	if (seg.count != 0)
810	<	return false;
811	<	sum += seg.modCount;
812	<	}
813	<	}
814	<	if (sum != 0L) { // recheck unless no modifications
815	<	for (int j = 0; j < segments.length; ++j) {
816	<	Segment<K,V> seg = segmentAt(segments, j);
817	<	if (seg != null) {
818	<	if (seg.count != 0)
819	<	return false;
820	<	sum -= seg.modCount;
821	<	}
822	<	}
823	<	if (sum != 0L)
824	<	return false;
825	<	}
826	<	return true;
2457	>	return sumCount() <= 0L; // ignore transient negative values
2458		}
2459
2460		/**
2461	<	* Returns the number of key-value mappings in this map.  If the
831	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
832	<	* <tt>Integer.MAX_VALUE</tt>.
833	<	*
834	<	* @return the number of key-value mappings in this map
2461	>	* {@inheritDoc}
2462		*/
2463		public int size() {
2464	<	// Try a few times to get accurate count. On failure due to
2465	<	// continuous async changes in table, resort to locking.
2466	<	final Segment<K,V>[] segments = this.segments;
2467	<	final int segmentCount = segments.length;
2468	<
842	<	long previousSum = 0L;
843	<	for (int retries = -1; retries < RETRIES_BEFORE_LOCK; retries++) {
844	<	long sum = 0L;    // sum of modCounts
845	<	long size = 0L;
846	<	for (int i = 0; i < segmentCount; i++) {
847	<	Segment<K,V> segment = segmentAt(segments, i);
848	<	if (segment != null) {
849	<	sum += segment.modCount;
850	<	size += segment.count;
851	<	}
852	<	}
853	<	if (sum == previousSum)
854	<	return ((size >>> 31) == 0) ? (int) size : Integer.MAX_VALUE;
855	<	previousSum = sum;
856	<	}
2464	>	long n = sumCount();
2465	>	return ((n < 0L) ? 0 :
2466	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2467	>	(int)n);
2468	>	}
2469
2470	<	long size = 0L;
2471	<	for (int i = 0; i < segmentCount; i++) {
2472	<	Segment<K,V> segment = ensureSegment(i);
2473	<	segment.lock();
2474	<	size += segment.count;
2475	<	}
2476	<	for (int i = 0; i < segmentCount; i++)
2477	<	segments[i].unlock();
2478	<	return ((size >>> 31) == 0) ? (int) size : Integer.MAX_VALUE;
2470	>	/**
2471	>	* Returns the number of mappings. This method should be used
2472	>	* instead of {@link #size} because a ConcurrentHashMap may
2473	>	* contain more mappings than can be represented as an int. The
2474	>	* value returned is an estimate; the actual count may differ if
2475	>	* there are concurrent insertions or removals.
2476	>	*
2477	>	* @return the number of mappings
2478	>	*/
2479	>	public long mappingCount() {
2480	>	long n = sumCount();
2481	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2482		}
2483
2484		/**
#	Line 877 | Line 2492 | public class ConcurrentHashMap<K, V> ext
2492		*
2493		* @throws NullPointerException if the specified key is null
2494		*/
880	–	@SuppressWarnings("unchecked")
2495		public V get(Object key) {
2496	<	Segment<K,V> s; // manually integrate access methods to reduce overhead
2497	<	HashEntry<K,V>[] tab;
2498	<	int h = hash(key.hashCode());
2499	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
2500	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
2501	<	(tab = s.table) != null) {
2502	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
2503	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
2504	<	e != null; e = e.next) {
2505	<	K k;
2506	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
2507	<	return e.value;
2508	<	}
2509	<	}
2510	<	return null;
2496	>	return internalGet(key);
2497	>	}
2498	>
2499	>	/**
2500	>	* Returns the value to which the specified key is mapped,
2501	>	* or the given defaultValue if this map contains no mapping for the key.
2502	>	*
2503	>	* @param key the key
2504	>	* @param defaultValue the value to return if this map contains
2505	>	* no mapping for the given key
2506	>	* @return the mapping for the key, if present; else the defaultValue
2507	>	* @throws NullPointerException if the specified key is null
2508	>	*/
2509	>	public V getValueOrDefault(Object key, V defaultValue) {
2510	>	V v;
2511	>	return (v = internalGet(key)) == null ? defaultValue : v;
2512		}
2513
2514		/**
2515		* Tests if the specified object is a key in this table.
2516		*
2517		* @param  key   possible key
2518	<	* @return <tt>true</tt> if and only if the specified object
2518	>	* @return {@code true} if and only if the specified object
2519		*         is a key in this table, as determined by the
2520	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
2520	>	*         {@code equals} method; {@code false} otherwise
2521		* @throws NullPointerException if the specified key is null
2522		*/
908	–	@SuppressWarnings("unchecked")
2523		public boolean containsKey(Object key) {
2524	<	Segment<K,V> s; // same as get() except no need for volatile value read
911	<	HashEntry<K,V>[] tab;
912	<	int h = hash(key.hashCode());
913	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
914	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
915	<	(tab = s.table) != null) {
916	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
917	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
918	<	e != null; e = e.next) {
919	<	K k;
920	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
921	<	return true;
922	<	}
923	<	}
924	<	return false;
2524	>	return internalGet(key) != null;
2525		}
2526
2527		/**
2528	<	* Returns <tt>true</tt> if this map maps one or more keys to the
2529	<	* specified value. Note: This method requires a full internal
2530	<	* traversal of the hash table, and so is much slower than
931	<	* method <tt>containsKey</tt>.
2528	>	* Returns {@code true} if this map maps one or more keys to the
2529	>	* specified value. Note: This method may require a full traversal
2530	>	* of the map, and is much slower than method {@code containsKey}.
2531		*
2532		* @param value value whose presence in this map is to be tested
2533	<	* @return <tt>true</tt> if this map maps one or more keys to the
2533	>	* @return {@code true} if this map maps one or more keys to the
2534		*         specified value
2535		* @throws NullPointerException if the specified value is null
2536		*/
2537		public boolean containsValue(Object value) {
939	–	// Same idea as size()
2538		if (value == null)
2539		throw new NullPointerException();
2540	<	final Segment<K,V>[] segments = this.segments;
2541	<	long previousSum = 0L;
2542	<	int lockCount = 0;
2543	<	try {
2544	<	for (int retries = -1; ; retries++) {
947	<	long sum = 0L;    // sum of modCounts
948	<	for (int j = 0; j < segments.length; j++) {
949	<	Segment<K,V> segment;
950	<	if (retries == RETRIES_BEFORE_LOCK) {
951	<	segment = ensureSegment(j);
952	<	segment.lock();
953	<	lockCount++;
954	<	} else {
955	<	segment = segmentAt(segments, j);
956	<	if (segment == null)
957	<	continue;
958	<	}
959	<	HashEntry<K,V>[] tab = segment.table;
960	<	if (tab != null) {
961	<	for (int i = 0 ; i < tab.length; i++) {
962	<	HashEntry<K,V> e;
963	<	for (e = entryAt(tab, i); e != null; e = e.next) {
964	<	V v = e.value;
965	<	if (v != null && value.equals(v))
966	<	return true;
967	<	}
968	<	}
969	<	sum += segment.modCount;
970	<	}
971	<	}
972	<	if ((retries >= 0 && sum == previousSum) || lockCount > 0)
973	<	return false;
974	<	previousSum = sum;
975	<	}
976	<	} finally {
977	<	for (int j = 0; j < lockCount; j++)
978	<	segments[j].unlock();
2540	>	V v;
2541	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2542	>	while ((v = it.advance()) != null) {
2543	>	if (v == value || value.equals(v))
2544	>	return true;
2545		}
2546	+	return false;
2547		}
2548
2549		/**
#	Line 988 | Line 2555 | public class ConcurrentHashMap<K, V> ext
2555		* Java Collections framework.
2556		*
2557		* @param  value a value to search for
2558	<	* @return <tt>true</tt> if and only if some key maps to the
2559	<	*         <tt>value</tt> argument in this table as
2560	<	*         determined by the <tt>equals</tt> method;
2561	<	*         <tt>false</tt> otherwise
2558	>	* @return {@code true} if and only if some key maps to the
2559	>	*         {@code value} argument in this table as
2560	>	*         determined by the {@code equals} method;
2561	>	*         {@code false} otherwise
2562		* @throws NullPointerException if the specified value is null
2563		*/
2564	<	public boolean contains(Object value) {
2564	>	@Deprecated public boolean contains(Object value) {
2565		return containsValue(value);
2566		}
2567
#	Line 1002 | Line 2569 | public class ConcurrentHashMap<K, V> ext
2569		* Maps the specified key to the specified value in this table.
2570		* Neither the key nor the value can be null.
2571		*
2572	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
2572	>	* <p>The value can be retrieved by calling the {@code get} method
2573		* with a key that is equal to the original key.
2574		*
2575		* @param key key with which the specified value is to be associated
2576		* @param value value to be associated with the specified key
2577	<	* @return the previous value associated with <tt>key</tt>, or
2578	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2577	>	* @return the previous value associated with {@code key}, or
2578	>	*         {@code null} if there was no mapping for {@code key}
2579		* @throws NullPointerException if the specified key or value is null
2580		*/
1014	–	@SuppressWarnings("unchecked")
2581		public V put(K key, V value) {
2582	<	Segment<K,V> s;
1017	<	if (value == null)
1018	<	throw new NullPointerException();
1019	<	int hash = hash(key.hashCode());
1020	<	int j = (hash >>> segmentShift) & segmentMask;
1021	<	if ((s = (Segment<K,V>)UNSAFE.getObject          // nonvolatile; recheck
1022	<	(segments, (j << SSHIFT) + SBASE)) == null) //  in ensureSegment
1023	<	s = ensureSegment(j);
1024	<	return s.put(key, hash, value, false);
2582	>	return internalPut(key, value, false);
2583		}
2584
2585		/**
2586		* {@inheritDoc}
2587		*
2588		* @return the previous value associated with the specified key,
2589	<	*         or <tt>null</tt> if there was no mapping for the key
2589	>	*         or {@code null} if there was no mapping for the key
2590		* @throws NullPointerException if the specified key or value is null
2591		*/
1034	–	@SuppressWarnings("unchecked")
2592		public V putIfAbsent(K key, V value) {
2593	<	Segment<K,V> s;
1037	<	if (value == null)
1038	<	throw new NullPointerException();
1039	<	int hash = hash(key.hashCode());
1040	<	int j = (hash >>> segmentShift) & segmentMask;
1041	<	if ((s = (Segment<K,V>)UNSAFE.getObject
1042	<	(segments, (j << SSHIFT) + SBASE)) == null)
1043	<	s = ensureSegment(j);
1044	<	return s.put(key, hash, value, true);
2593	>	return internalPut(key, value, true);
2594		}
2595
2596		/**
#	Line 1052 | Line 2601 | public class ConcurrentHashMap<K, V> ext
2601		* @param m mappings to be stored in this map
2602		*/
2603		public void putAll(Map<? extends K, ? extends V> m) {
2604	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
2605	<	put(e.getKey(), e.getValue());
2604	>	internalPutAll(m);
2605	>	}
2606	>
2607	>	/**
2608	>	* If the specified key is not already associated with a value (or
2609	>	* is mapped to {@code null}), attempts to compute its value using
2610	>	* the given mapping function and enters it into this map unless
2611	>	* {@code null}. The entire method invocation is performed
2612	>	* atomically, so the function is applied at most once per key.
2613	>	* Some attempted update operations on this map by other threads
2614	>	* may be blocked while computation is in progress, so the
2615	>	* computation should be short and simple, and must not attempt to
2616	>	* update any other mappings of this Map.
2617	>	*
2618	>	* @param key key with which the specified value is to be associated
2619	>	* @param mappingFunction the function to compute a value
2620	>	* @return the current (existing or computed) value associated with
2621	>	*         the specified key, or null if the computed value is null
2622	>	* @throws NullPointerException if the specified key or mappingFunction
2623	>	*         is null
2624	>	* @throws IllegalStateException if the computation detectably
2625	>	*         attempts a recursive update to this map that would
2626	>	*         otherwise never complete
2627	>	* @throws RuntimeException or Error if the mappingFunction does so,
2628	>	*         in which case the mapping is left unestablished
2629	>	*/
2630	>	public V computeIfAbsent
2631	>	(K key, Function<? super K, ? extends V> mappingFunction) {
2632	>	return internalComputeIfAbsent(key, mappingFunction);
2633	>	}
2634	>
2635	>	/**
2636	>	* If the value for the specified key is present and non-null,
2637	>	* attempts to compute a new mapping given the key and its current
2638	>	* mapped value.  The entire method invocation is performed
2639	>	* atomically.  Some attempted update operations on this map by
2640	>	* other threads may be blocked while computation is in progress,
2641	>	* so the computation should be short and simple, and must not
2642	>	* attempt to update any other mappings of this Map.
2643	>	*
2644	>	* @param key key with which the specified value is to be associated
2645	>	* @param remappingFunction the function to compute a value
2646	>	* @return the new value associated with the specified key, or null if none
2647	>	* @throws NullPointerException if the specified key or remappingFunction
2648	>	*         is null
2649	>	* @throws IllegalStateException if the computation detectably
2650	>	*         attempts a recursive update to this map that would
2651	>	*         otherwise never complete
2652	>	* @throws RuntimeException or Error if the remappingFunction does so,
2653	>	*         in which case the mapping is unchanged
2654	>	*/
2655	>	public V computeIfPresent
2656	>	(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2657	>	return internalCompute(key, true, remappingFunction);
2658	>	}
2659	>
2660	>	/**
2661	>	* Attempts to compute a mapping for the specified key and its
2662	>	* current mapped value (or {@code null} if there is no current
2663	>	* mapping). The entire method invocation is performed atomically.
2664	>	* Some attempted update operations on this map by other threads
2665	>	* may be blocked while computation is in progress, so the
2666	>	* computation should be short and simple, and must not attempt to
2667	>	* update any other mappings of this Map.
2668	>	*
2669	>	* @param key key with which the specified value is to be associated
2670	>	* @param remappingFunction the function to compute a value
2671	>	* @return the new value associated with the specified key, or null if none
2672	>	* @throws NullPointerException if the specified key or remappingFunction
2673	>	*         is null
2674	>	* @throws IllegalStateException if the computation detectably
2675	>	*         attempts a recursive update to this map that would
2676	>	*         otherwise never complete
2677	>	* @throws RuntimeException or Error if the remappingFunction does so,
2678	>	*         in which case the mapping is unchanged
2679	>	*/
2680	>	public V compute
2681	>	(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2682	>	return internalCompute(key, false, remappingFunction);
2683	>	}
2684	>
2685	>	/**
2686	>	* If the specified key is not already associated with a
2687	>	* (non-null) value, associates it with the given value.
2688	>	* Otherwise, replaces the value with the results of the given
2689	>	* remapping function, or removes if {@code null}. The entire
2690	>	* method invocation is performed atomically.  Some attempted
2691	>	* update operations on this map by other threads may be blocked
2692	>	* while computation is in progress, so the computation should be
2693	>	* short and simple, and must not attempt to update any other
2694	>	* mappings of this Map.
2695	>	*
2696	>	* @param key key with which the specified value is to be associated
2697	>	* @param value the value to use if absent
2698	>	* @param remappingFunction the function to recompute a value if present
2699	>	* @return the new value associated with the specified key, or null if none
2700	>	* @throws NullPointerException if the specified key or the
2701	>	*         remappingFunction is null
2702	>	* @throws RuntimeException or Error if the remappingFunction does so,
2703	>	*         in which case the mapping is unchanged
2704	>	*/
2705	>	public V merge
2706	>	(K key, V value,
2707	>	BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
2708	>	return internalMerge(key, value, remappingFunction);
2709		}
2710
2711		/**
#	Line 1061 | Line 2713 | public class ConcurrentHashMap<K, V> ext
2713		* This method does nothing if the key is not in the map.
2714		*
2715		* @param  key the key that needs to be removed
2716	<	* @return the previous value associated with <tt>key</tt>, or
2717	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2716	>	* @return the previous value associated with {@code key}, or
2717	>	*         {@code null} if there was no mapping for {@code key}
2718		* @throws NullPointerException if the specified key is null
2719		*/
2720		public V remove(Object key) {
2721	<	int hash = hash(key.hashCode());
1070	<	Segment<K,V> s = segmentForHash(hash);
1071	<	return s == null ? null : s.remove(key, hash, null);
2721	>	return internalReplace(key, null, null);
2722		}
2723
2724		/**
#	Line 1077 | Line 2727 | public class ConcurrentHashMap<K, V> ext
2727		* @throws NullPointerException if the specified key is null
2728		*/
2729		public boolean remove(Object key, Object value) {
2730	<	int hash = hash(key.hashCode());
1081	<	Segment<K,V> s;
1082	<	return value != null && (s = segmentForHash(hash)) != null &&
1083	<	s.remove(key, hash, value) != null;
2730	>	return value != null && internalReplace(key, null, value) != null;
2731		}
2732
2733		/**
#	Line 1089 | Line 2736 | public class ConcurrentHashMap<K, V> ext
2736		* @throws NullPointerException if any of the arguments are null
2737		*/
2738		public boolean replace(K key, V oldValue, V newValue) {
2739	<	int hash = hash(key.hashCode());
1093	<	if (oldValue == null || newValue == null)
2739	>	if (key == null || oldValue == null || newValue == null)
2740		throw new NullPointerException();
2741	<	Segment<K,V> s = segmentForHash(hash);
1096	<	return s != null && s.replace(key, hash, oldValue, newValue);
2741	>	return internalReplace(key, newValue, oldValue) != null;
2742		}
2743
2744		/**
2745		* {@inheritDoc}
2746		*
2747		* @return the previous value associated with the specified key,
2748	<	*         or <tt>null</tt> if there was no mapping for the key
2748	>	*         or {@code null} if there was no mapping for the key
2749		* @throws NullPointerException if the specified key or value is null
2750		*/
2751		public V replace(K key, V value) {
2752	<	int hash = hash(key.hashCode());
1108	<	if (value == null)
2752	>	if (key == null || value == null)
2753		throw new NullPointerException();
2754	<	Segment<K,V> s = segmentForHash(hash);
1111	<	return s == null ? null : s.replace(key, hash, value);
2754	>	return internalReplace(key, value, null);
2755		}
2756
2757		/**
2758		* Removes all of the mappings from this map.
2759		*/
2760		public void clear() {
2761	<	final Segment<K,V>[] segments = this.segments;
1119	<	for (int j = 0; j < segments.length; ++j) {
1120	<	Segment<K,V> s = segmentAt(segments, j);
1121	<	if (s != null)
1122	<	s.clear();
1123	<	}
2761	>	internalClear();
2762		}
2763
2764		/**
2765		* Returns a {@link Set} view of the keys contained in this map.
2766		* The set is backed by the map, so changes to the map are
2767	<	* reflected in the set, and vice-versa.  The set supports element
1130	<	* removal, which removes the corresponding mapping from this map,
1131	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
1132	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
1133	<	* operations.  It does not support the <tt>add</tt> or
1134	<	* <tt>addAll</tt> operations.
2767	>	* reflected in the set, and vice-versa.
2768		*
2769	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2770	<	* that will never throw {@link ConcurrentModificationException},
2771	<	* and guarantees to traverse elements as they existed upon
2772	<	* construction of the iterator, and may (but is not guaranteed to)
2773	<	* reflect any modifications subsequent to construction.
2769	>	* @return the set view
2770	>	*/
2771	>	public KeySetView<K,V> keySet() {
2772	>	KeySetView<K,V> ks = keySet;
2773	>	return (ks != null) ? ks : (keySet = new KeySetView<K,V>(this, null));
2774	>	}
2775	>
2776	>	/**
2777	>	* Returns a {@link Set} view of the keys in this map, using the
2778	>	* given common mapped value for any additions (i.e., {@link
2779	>	* Collection#add} and {@link Collection#addAll}). This is of
2780	>	* course only appropriate if it is acceptable to use the same
2781	>	* value for all additions from this view.
2782	>	*
2783	>	* @param mappedValue the mapped value to use for any
2784	>	* additions.
2785	>	* @return the set view
2786	>	* @throws NullPointerException if the mappedValue is null
2787		*/
2788	<	public Set<K> keySet() {
2789	<	Set<K> ks = keySet;
2790	<	return (ks != null) ? ks : (keySet = new KeySet());
2788	>	public KeySetView<K,V> keySet(V mappedValue) {
2789	>	if (mappedValue == null)
2790	>	throw new NullPointerException();
2791	>	return new KeySetView<K,V>(this, mappedValue);
2792		}
2793
2794		/**
2795		* Returns a {@link Collection} view of the values contained in this map.
2796		* The collection is backed by the map, so changes to the map are
2797	<	* reflected in the collection, and vice-versa.  The collection
1151	<	* supports element removal, which removes the corresponding
1152	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
1153	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
1154	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
1155	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
1156	<	*
1157	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1158	<	* that will never throw {@link ConcurrentModificationException},
1159	<	* and guarantees to traverse elements as they existed upon
1160	<	* construction of the iterator, and may (but is not guaranteed to)
1161	<	* reflect any modifications subsequent to construction.
2797	>	* reflected in the collection, and vice-versa.
2798		*/
2799	<	public Collection<V> values() {
2800	<	Collection<V> vs = values;
2801	<	return (vs != null) ? vs : (values = new Values());
2799	>	public ValuesView<K,V> values() {
2800	>	ValuesView<K,V> vs = values;
2801	>	return (vs != null) ? vs : (values = new ValuesView<K,V>(this));
2802		}
2803
2804		/**
#	Line 1170 | Line 2806 | public class ConcurrentHashMap<K, V> ext
2806		* The set is backed by the map, so changes to the map are
2807		* reflected in the set, and vice-versa.  The set supports element
2808		* removal, which removes the corresponding mapping from the map,
2809	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2810	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2811	<	* operations.  It does not support the <tt>add</tt> or
2812	<	* <tt>addAll</tt> operations.
2809	>	* via the {@code Iterator.remove}, {@code Set.remove},
2810	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
2811	>	* operations.  It does not support the {@code add} or
2812	>	* {@code addAll} operations.
2813		*
2814	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2814	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2815		* that will never throw {@link ConcurrentModificationException},
2816		* and guarantees to traverse elements as they existed upon
2817		* construction of the iterator, and may (but is not guaranteed to)
2818		* reflect any modifications subsequent to construction.
2819		*/
2820		public Set<Map.Entry<K,V>> entrySet() {
2821	<	Set<Map.Entry<K,V>> es = entrySet;
2822	<	return (es != null) ? es : (entrySet = new EntrySet());
2821	>	EntrySetView<K,V> es = entrySet;
2822	>	return (es != null) ? es : (entrySet = new EntrySetView<K,V>(this));
2823		}
2824
2825		/**
#	Line 1193 | Line 2829 | public class ConcurrentHashMap<K, V> ext
2829		* @see #keySet()
2830		*/
2831		public Enumeration<K> keys() {
2832	<	return new KeyIterator();
2832	>	return new KeyIterator<K,V>(this);
2833		}
2834
2835		/**
#	Line 1203 | Line 2839 | public class ConcurrentHashMap<K, V> ext
2839		* @see #values()
2840		*/
2841		public Enumeration<V> elements() {
2842	<	return new ValueIterator();
2842	>	return new ValueIterator<K,V>(this);
2843		}
2844
2845	<	/* ---------------- Iterator Support -------------- */
2846	<
2847	<	abstract class HashIterator {
2848	<	int nextSegmentIndex;
2849	<	int nextTableIndex;
2850	<	HashEntry<K,V>[] currentTable;
2851	<	HashEntry<K, V> nextEntry;
2852	<	HashEntry<K, V> lastReturned;
2853	<
2854	<	HashIterator() {
2855	<	nextSegmentIndex = segments.length - 1;
2856	<	nextTableIndex = -1;
2857	<	advance();
2858	<	}
2845	>	/**
2846	>	* Returns the hash code value for this {@link Map}, i.e.,
2847	>	* the sum of, for each key-value pair in the map,
2848	>	* {@code key.hashCode() ^ value.hashCode()}.
2849	>	*
2850	>	* @return the hash code value for this map
2851	>	*/
2852	>	public int hashCode() {
2853	>	int h = 0;
2854	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2855	>	V v;
2856	>	while ((v = it.advance()) != null) {
2857	>	h += it.nextKey.hashCode() ^ v.hashCode();
2858	>	}
2859	>	return h;
2860	>	}
2861
2862	<	/**
2863	<	* Sets nextEntry to first node of next non-empty table
2864	<	* (in backwards order, to simplify checks).
2865	<	*/
2866	<	final void advance() {
2862	>	/**
2863	>	* Returns a string representation of this map.  The string
2864	>	* representation consists of a list of key-value mappings (in no
2865	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
2866	>	* mappings are separated by the characters {@code ", "} (comma
2867	>	* and space).  Each key-value mapping is rendered as the key
2868	>	* followed by an equals sign ("{@code =}") followed by the
2869	>	* associated value.
2870	>	*
2871	>	* @return a string representation of this map
2872	>	*/
2873	>	public String toString() {
2874	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2875	>	StringBuilder sb = new StringBuilder();
2876	>	sb.append('{');
2877	>	V v;
2878	>	if ((v = it.advance()) != null) {
2879		for (;;) {
2880	<	if (nextTableIndex >= 0) {
2881	<	if ((nextEntry = entryAt(currentTable,
2882	<	nextTableIndex--)) != null)
2883	<	break;
2884	<	}
1235	<	else if (nextSegmentIndex >= 0) {
1236	<	Segment<K,V> seg = segmentAt(segments, nextSegmentIndex--);
1237	<	if (seg != null && (currentTable = seg.table) != null)
1238	<	nextTableIndex = currentTable.length - 1;
1239	<	}
1240	<	else
2880	>	Object k = it.nextKey;
2881	>	sb.append(k == this ? "(this Map)" : k);
2882	>	sb.append('=');
2883	>	sb.append(v == this ? "(this Map)" : v);
2884	>	if ((v = it.advance()) == null)
2885		break;
2886	+	sb.append(',').append(' ');
2887		}
2888		}
2889	+	return sb.append('}').toString();
2890	+	}
2891
2892	<	final HashEntry<K,V> nextEntry() {
2893	<	HashEntry<K,V> e = nextEntry;
2894	<	if (e == null)
2892	>	/**
2893	>	* Compares the specified object with this map for equality.
2894	>	* Returns {@code true} if the given object is a map with the same
2895	>	* mappings as this map.  This operation may return misleading
2896	>	* results if either map is concurrently modified during execution
2897	>	* of this method.
2898	>	*
2899	>	* @param o object to be compared for equality with this map
2900	>	* @return {@code true} if the specified object is equal to this map
2901	>	*/
2902	>	public boolean equals(Object o) {
2903	>	if (o != this) {
2904	>	if (!(o instanceof Map))
2905	>	return false;
2906	>	Map<?,?> m = (Map<?,?>) o;
2907	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
2908	>	V val;
2909	>	while ((val = it.advance()) != null) {
2910	>	Object v = m.get(it.nextKey);
2911	>	if (v == null || (v != val && !v.equals(val)))
2912	>	return false;
2913	>	}
2914	>	for (Map.Entry<?,?> e : m.entrySet()) {
2915	>	Object mk, mv, v;
2916	>	if ((mk = e.getKey()) == null ||
2917	>	(mv = e.getValue()) == null ||
2918	>	(v = internalGet(mk)) == null ||
2919	>	(mv != v && !mv.equals(v)))
2920	>	return false;
2921	>	}
2922	>	}
2923	>	return true;
2924	>	}
2925	>
2926	>	/* ----------------Iterators -------------- */
2927	>
2928	>	@SuppressWarnings("serial") static final class KeyIterator<K,V>
2929	>	extends Traverser<K,V,Object>
2930	>	implements Spliterator<K>, Iterator<K>, Enumeration<K> {
2931	>	KeyIterator(ConcurrentHashMap<K, V> map) { super(map); }
2932	>	KeyIterator(ConcurrentHashMap<K, V> map, Traverser<K,V,Object> it) {
2933	>	super(map, it);
2934	>	}
2935	>	public KeyIterator<K,V> trySplit() {
2936	>	if (tab != null && baseIndex == baseLimit)
2937	>	return null;
2938	>	return new KeyIterator<K,V>(map, this);
2939	>	}
2940	>	@SuppressWarnings("unchecked") public final K next() {
2941	>	if (nextVal == null && advance() == null)
2942		throw new NoSuchElementException();
2943	<	lastReturned = e; // cannot assign until after null check
2944	<	if ((nextEntry = e.next) == null)
2945	<	advance();
1252	<	return e;
2943	>	Object k = nextKey;
2944	>	nextVal = null;
2945	>	return (K) k;
2946		}
2947
2948	<	public final boolean hasNext() { return nextEntry != null; }
1256	<	public final boolean hasMoreElements() { return nextEntry != null; }
2948	>	public final K nextElement() { return next(); }
2949
2950	<	public final void remove() {
2951	<	if (lastReturned == null)
2952	<	throw new IllegalStateException();
2953	<	ConcurrentHashMap.this.remove(lastReturned.key);
2954	<	lastReturned = null;
2950	>	public Iterator<K> asIterator() { return this; }
2951	>
2952	>	public void forEach(Block<? super K> action) {
2953	>	if (action == null) throw new NullPointerException();
2954	>	while (advance() != null)
2955	>	action.accept((K)nextKey);
2956	>	}
2957	>
2958	>	public boolean tryAdvance(Block<? super K> block) {
2959	>	if (block == null) throw new NullPointerException();
2960	>	if (advance() == null)
2961	>	return false;
2962	>	block.accept((K)nextKey);
2963	>	return true;
2964		}
2965		}
2966
2967	<	final class KeyIterator
2968	<	extends HashIterator
2969	<	implements Iterator<K>, Enumeration<K>
2970	<	{
2971	<	public final K next()        { return super.nextEntry().key; }
2972	<	public final K nextElement() { return super.nextEntry().key; }
2967	>	@SuppressWarnings("serial") static final class ValueIterator<K,V>
2968	>	extends Traverser<K,V,Object>
2969	>	implements Spliterator<V>, Iterator<V>, Enumeration<V> {
2970	>	ValueIterator(ConcurrentHashMap<K, V> map) { super(map); }
2971	>	ValueIterator(ConcurrentHashMap<K, V> map, Traverser<K,V,Object> it) {
2972	>	super(map, it);
2973	>	}
2974	>	public ValueIterator<K,V> trySplit() {
2975	>	if (tab != null && baseIndex == baseLimit)
2976	>	return null;
2977	>	return new ValueIterator<K,V>(map, this);
2978	>	}
2979	>
2980	>	public final V next() {
2981	>	V v;
2982	>	if ((v = nextVal) == null && (v = advance()) == null)
2983	>	throw new NoSuchElementException();
2984	>	nextVal = null;
2985	>	return v;
2986	>	}
2987	>
2988	>	public final V nextElement() { return next(); }
2989	>
2990	>	public Iterator<V> asIterator() { return this; }
2991	>
2992	>	public void forEach(Block<? super V> action) {
2993	>	if (action == null) throw new NullPointerException();
2994	>	V v;
2995	>	while ((v = advance()) != null)
2996	>	action.accept(v);
2997	>	}
2998	>
2999	>	public boolean tryAdvance(Block<? super V> block) {
3000	>	V v;
3001	>	if (block == null) throw new NullPointerException();
3002	>	if ((v = advance()) == null)
3003	>	return false;
3004	>	block.accept(v);
3005	>	return true;
3006	>	}
3007	>
3008		}
3009
3010	<	final class ValueIterator
3011	<	extends HashIterator
3012	<	implements Iterator<V>, Enumeration<V>
3013	<	{
3014	<	public final V next()        { return super.nextEntry().value; }
3015	<	public final V nextElement() { return super.nextEntry().value; }
3010	>	@SuppressWarnings("serial") static final class EntryIterator<K,V>
3011	>	extends Traverser<K,V,Object>
3012	>	implements Spliterator<Map.Entry<K,V>>, Iterator<Map.Entry<K,V>> {
3013	>	EntryIterator(ConcurrentHashMap<K, V> map) { super(map); }
3014	>	EntryIterator(ConcurrentHashMap<K, V> map, Traverser<K,V,Object> it) {
3015	>	super(map, it);
3016	>	}
3017	>	public EntryIterator<K,V> trySplit() {
3018	>	if (tab != null && baseIndex == baseLimit)
3019	>	return null;
3020	>	return new EntryIterator<K,V>(map, this);
3021	>	}
3022	>
3023	>	@SuppressWarnings("unchecked") public final Map.Entry<K,V> next() {
3024	>	V v;
3025	>	if ((v = nextVal) == null && (v = advance()) == null)
3026	>	throw new NoSuchElementException();
3027	>	Object k = nextKey;
3028	>	nextVal = null;
3029	>	return new MapEntry<K,V>((K)k, v, map);
3030	>	}
3031	>
3032	>	public Iterator<Map.Entry<K,V>> asIterator() { return this; }
3033	>
3034	>	public void forEach(Block<? super Map.Entry<K,V>> action) {
3035	>	if (action == null) throw new NullPointerException();
3036	>	V v;
3037	>	while ((v = advance()) != null)
3038	>	action.accept(entryFor((K)nextKey, v));
3039	>	}
3040	>
3041	>	public boolean tryAdvance(Block<? super Map.Entry<K,V>> block) {
3042	>	V v;
3043	>	if (block == null) throw new NullPointerException();
3044	>	if ((v = advance()) == null)
3045	>	return false;
3046	>	block.accept(entryFor((K)nextKey, v));
3047	>	return true;
3048	>	}
3049	>
3050		}
3051
3052		/**
3053	<	* Custom Entry class used by EntryIterator.next(), that relays
1284	<	* setValue changes to the underlying map.
3053	>	* Exported Entry for iterators
3054		*/
3055	<	final class WriteThroughEntry
3056	<	extends AbstractMap.SimpleEntry<K,V>
3057	<	{
3058	<	static final long serialVersionUID = 7249069246763182397L;
3059	<
3060	<	WriteThroughEntry(K k, V v) {
3061	<	super(k,v);
3055	>	static final class MapEntry<K,V> implements Map.Entry<K, V> {
3056	>	final K key; // non-null
3057	>	V val;       // non-null
3058	>	final ConcurrentHashMap<K, V> map;
3059	>	MapEntry(K key, V val, ConcurrentHashMap<K, V> map) {
3060	>	this.key = key;
3061	>	this.val = val;
3062	>	this.map = map;
3063	>	}
3064	>	public final K getKey()       { return key; }
3065	>	public final V getValue()     { return val; }
3066	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
3067	>	public final String toString(){ return key + "=" + val; }
3068	>
3069	>	public final boolean equals(Object o) {
3070	>	Object k, v; Map.Entry<?,?> e;
3071	>	return ((o instanceof Map.Entry) &&
3072	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3073	>	(v = e.getValue()) != null &&
3074	>	(k == key || k.equals(key)) &&
3075	>	(v == val || v.equals(val)));
3076		}
3077
3078		/**
3079		* Sets our entry's value and writes through to the map. The
3080	<	* value to return is somewhat arbitrary here. Since a
3081	<	* WriteThroughEntry does not necessarily track asynchronous
3082	<	* changes, the most recent "previous" value could be
3083	<	* different from what we return (or could even have been
3084	<	* removed in which case the put will re-establish). We do not
1302	<	* and cannot guarantee more.
3080	>	* value to return is somewhat arbitrary here. Since we do not
3081	>	* necessarily track asynchronous changes, the most recent
3082	>	* "previous" value could be different from what we return (or
3083	>	* could even have been removed in which case the put will
3084	>	* re-establish). We do not and cannot guarantee more.
3085		*/
3086	<	public V setValue(V value) {
3086	>	public final V setValue(V value) {
3087		if (value == null) throw new NullPointerException();
3088	<	V v = super.setValue(value);
3089	<	ConcurrentHashMap.this.put(getKey(), value);
3088	>	V v = val;
3089	>	val = value;
3090	>	map.put(key, value);
3091		return v;
3092		}
3093		}
3094
3095	<	final class EntryIterator
3096	<	extends HashIterator
3097	<	implements Iterator<Entry<K,V>>
3098	<	{
3099	<	public Map.Entry<K,V> next() {
3100	<	HashEntry<K,V> e = super.nextEntry();
3101	<	return new WriteThroughEntry(e.key, e.value);
3102	<	}
3095	>	/**
3096	>	* Returns exportable snapshot entry for the given key and value
3097	>	* when write-through can't or shouldn't be used.
3098	>	*/
3099	>	static <K,V> AbstractMap.SimpleEntry<K,V> entryFor(K k, V v) {
3100	>	return new AbstractMap.SimpleEntry<K,V>(k, v);
3101	>	}
3102	>
3103	>	/* ---------------- Serialization Support -------------- */
3104	>
3105	>	/**
3106	>	* Stripped-down version of helper class used in previous version,
3107	>	* declared for the sake of serialization compatibility
3108	>	*/
3109	>	static class Segment<K,V> implements Serializable {
3110	>	private static final long serialVersionUID = 2249069246763182397L;
3111	>	final float loadFactor;
3112	>	Segment(float lf) { this.loadFactor = lf; }
3113		}
3114
3115	<	final class KeySet extends AbstractSet<K> {
3116	<	public Iterator<K> iterator() {
3117	<	return new KeyIterator();
3115	>	/**
3116	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
3117	>	* stream (i.e., serializes it).
3118	>	* @param s the stream
3119	>	* @serialData
3120	>	* the key (Object) and value (Object)
3121	>	* for each key-value mapping, followed by a null pair.
3122	>	* The key-value mappings are emitted in no particular order.
3123	>	*/
3124	>	@SuppressWarnings("unchecked") private void writeObject
3125	>	(java.io.ObjectOutputStream s)
3126	>	throws java.io.IOException {
3127	>	if (segments == null) { // for serialization compatibility
3128	>	segments = (Segment<K,V>[])
3129	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3130	>	for (int i = 0; i < segments.length; ++i)
3131	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
3132		}
3133	<	public int size() {
3134	<	return ConcurrentHashMap.this.size();
3133	>	s.defaultWriteObject();
3134	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3135	>	V v;
3136	>	while ((v = it.advance()) != null) {
3137	>	s.writeObject(it.nextKey);
3138	>	s.writeObject(v);
3139		}
3140	<	public boolean isEmpty() {
3141	<	return ConcurrentHashMap.this.isEmpty();
3140	>	s.writeObject(null);
3141	>	s.writeObject(null);
3142	>	segments = null; // throw away
3143	>	}
3144	>
3145	>	/**
3146	>	* Reconstitutes the instance from a stream (that is, deserializes it).
3147	>	* @param s the stream
3148	>	*/
3149	>	@SuppressWarnings("unchecked") private void readObject
3150	>	(java.io.ObjectInputStream s)
3151	>	throws java.io.IOException, ClassNotFoundException {
3152	>	s.defaultReadObject();
3153	>	this.segments = null; // unneeded
3154	>
3155	>	// Create all nodes, then place in table once size is known
3156	>	long size = 0L;
3157	>	Node<V> p = null;
3158	>	for (;;) {
3159	>	K k = (K) s.readObject();
3160	>	V v = (V) s.readObject();
3161	>	if (k != null && v != null) {
3162	>	int h = spread(k.hashCode());
3163	>	p = new Node<V>(h, k, v, p);
3164	>	++size;
3165	>	}
3166	>	else
3167	>	break;
3168		}
3169	<	public boolean contains(Object o) {
3170	<	return ConcurrentHashMap.this.containsKey(o);
3169	>	if (p != null) {
3170	>	boolean init = false;
3171	>	int n;
3172	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3173	>	n = MAXIMUM_CAPACITY;
3174	>	else {
3175	>	int sz = (int)size;
3176	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
3177	>	}
3178	>	int sc = sizeCtl;
3179	>	boolean collide = false;
3180	>	if (n > sc &&
3181	>	U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
3182	>	try {
3183	>	if (table == null) {
3184	>	init = true;
3185	>	@SuppressWarnings("rawtypes") Node[] rt = new Node[n];
3186	>	Node<V>[] tab = (Node<V>[])rt;
3187	>	int mask = n - 1;
3188	>	while (p != null) {
3189	>	int j = p.hash & mask;
3190	>	Node<V> next = p.next;
3191	>	Node<V> q = p.next = tabAt(tab, j);
3192	>	setTabAt(tab, j, p);
3193	>	if (!collide && q != null && q.hash == p.hash)
3194	>	collide = true;
3195	>	p = next;
3196	>	}
3197	>	table = tab;
3198	>	addCount(size, -1);
3199	>	sc = n - (n >>> 2);
3200	>	}
3201	>	} finally {
3202	>	sizeCtl = sc;
3203	>	}
3204	>	if (collide) { // rescan and convert to TreeBins
3205	>	Node<V>[] tab = table;
3206	>	for (int i = 0; i < tab.length; ++i) {
3207	>	int c = 0;
3208	>	for (Node<V> e = tabAt(tab, i); e != null; e = e.next) {
3209	>	if (++c > TREE_THRESHOLD &&
3210	>	(e.key instanceof Comparable)) {
3211	>	replaceWithTreeBin(tab, i, e.key);
3212	>	break;
3213	>	}
3214	>	}
3215	>	}
3216	>	}
3217	>	}
3218	>	if (!init) { // Can only happen if unsafely published.
3219	>	while (p != null) {
3220	>	internalPut((K)p.key, p.val, false);
3221	>	p = p.next;
3222	>	}
3223	>	}
3224		}
3225	<	public boolean remove(Object o) {
3226	<	return ConcurrentHashMap.this.remove(o) != null;
3225	>	}
3226	>
3227	>	// -------------------------------------------------------
3228	>
3229	>	// Sequential bulk operations
3230	>
3231	>	/**
3232	>	* Performs the given action for each (key, value).
3233	>	*
3234	>	* @param action the action
3235	>	*/
3236	>	@SuppressWarnings("unchecked") public void forEachSequentially
3237	>	(BiBlock<? super K, ? super V> action) {
3238	>	if (action == null) throw new NullPointerException();
3239	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3240	>	V v;
3241	>	while ((v = it.advance()) != null)
3242	>	action.accept((K)it.nextKey, v);
3243	>	}
3244	>
3245	>	/**
3246	>	* Performs the given action for each non-null transformation
3247	>	* of each (key, value).
3248	>	*
3249	>	* @param transformer a function returning the transformation
3250	>	* for an element, or null of there is no transformation (in
3251	>	* which case the action is not applied).
3252	>	* @param action the action
3253	>	*/
3254	>	@SuppressWarnings("unchecked") public <U> void forEachSequentially
3255	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3256	>	Block<? super U> action) {
3257	>	if (transformer == null || action == null)
3258	>	throw new NullPointerException();
3259	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3260	>	V v; U u;
3261	>	while ((v = it.advance()) != null) {
3262	>	if ((u = transformer.apply((K)it.nextKey, v)) != null)
3263	>	action.accept(u);
3264		}
3265	<	public void clear() {
3266	<	ConcurrentHashMap.this.clear();
3265	>	}
3266	>
3267	>	/**
3268	>	* Returns a non-null result from applying the given search
3269	>	* function on each (key, value), or null if none.
3270	>	*
3271	>	* @param searchFunction a function returning a non-null
3272	>	* result on success, else null
3273	>	* @return a non-null result from applying the given search
3274	>	* function on each (key, value), or null if none
3275	>	*/
3276	>	@SuppressWarnings("unchecked") public <U> U searchSequentially
3277	>	(BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3278	>	if (searchFunction == null) throw new NullPointerException();
3279	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3280	>	V v; U u;
3281	>	while ((v = it.advance()) != null) {
3282	>	if ((u = searchFunction.apply((K)it.nextKey, v)) != null)
3283	>	return u;
3284		}
3285	+	return null;
3286		}
3287
3288	<	final class Values extends AbstractCollection<V> {
3289	<	public Iterator<V> iterator() {
3290	<	return new ValueIterator();
3288	>	/**
3289	>	* Returns the result of accumulating the given transformation
3290	>	* of all (key, value) pairs using the given reducer to
3291	>	* combine values, or null if none.
3292	>	*
3293	>	* @param transformer a function returning the transformation
3294	>	* for an element, or null of there is no transformation (in
3295	>	* which case it is not combined).
3296	>	* @param reducer a commutative associative combining function
3297	>	* @return the result of accumulating the given transformation
3298	>	* of all (key, value) pairs
3299	>	*/
3300	>	@SuppressWarnings("unchecked") public <U> U reduceSequentially
3301	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3302	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3303	>	if (transformer == null || reducer == null)
3304	>	throw new NullPointerException();
3305	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3306	>	U r = null, u; V v;
3307	>	while ((v = it.advance()) != null) {
3308	>	if ((u = transformer.apply((K)it.nextKey, v)) != null)
3309	>	r = (r == null) ? u : reducer.apply(r, u);
3310		}
3311	<	public int size() {
3312	<	return ConcurrentHashMap.this.size();
3311	>	return r;
3312	>	}
3313	>
3314	>	/**
3315	>	* Returns the result of accumulating the given transformation
3316	>	* of all (key, value) pairs using the given reducer to
3317	>	* combine values, and the given basis as an identity value.
3318	>	*
3319	>	* @param transformer a function returning the transformation
3320	>	* for an element
3321	>	* @param basis the identity (initial default value) for the reduction
3322	>	* @param reducer a commutative associative combining function
3323	>	* @return the result of accumulating the given transformation
3324	>	* of all (key, value) pairs
3325	>	*/
3326	>	@SuppressWarnings("unchecked") public double reduceToDoubleSequentially
3327	>	(DoubleBiFunction<? super K, ? super V> transformer,
3328	>	double basis,
3329	>	DoubleBinaryOperator reducer) {
3330	>	if (transformer == null || reducer == null)
3331	>	throw new NullPointerException();
3332	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3333	>	double r = basis; V v;
3334	>	while ((v = it.advance()) != null)
3335	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble((K)it.nextKey, v));
3336	>	return r;
3337	>	}
3338	>
3339	>	/**
3340	>	* Returns the result of accumulating the given transformation
3341	>	* of all (key, value) pairs using the given reducer to
3342	>	* combine values, and the given basis as an identity value.
3343	>	*
3344	>	* @param transformer a function returning the transformation
3345	>	* for an element
3346	>	* @param basis the identity (initial default value) for the reduction
3347	>	* @param reducer a commutative associative combining function
3348	>	* @return the result of accumulating the given transformation
3349	>	* of all (key, value) pairs
3350	>	*/
3351	>	@SuppressWarnings("unchecked") public long reduceToLongSequentially
3352	>	(LongBiFunction<? super K, ? super V> transformer,
3353	>	long basis,
3354	>	LongBinaryOperator reducer) {
3355	>	if (transformer == null || reducer == null)
3356	>	throw new NullPointerException();
3357	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3358	>	long r = basis; V v;
3359	>	while ((v = it.advance()) != null)
3360	>	r = reducer.applyAsLong(r, transformer.applyAsLong((K)it.nextKey, v));
3361	>	return r;
3362	>	}
3363	>
3364	>	/**
3365	>	* Returns the result of accumulating the given transformation
3366	>	* of all (key, value) pairs using the given reducer to
3367	>	* combine values, and the given basis as an identity value.
3368	>	*
3369	>	* @param transformer a function returning the transformation
3370	>	* for an element
3371	>	* @param basis the identity (initial default value) for the reduction
3372	>	* @param reducer a commutative associative combining function
3373	>	* @return the result of accumulating the given transformation
3374	>	* of all (key, value) pairs
3375	>	*/
3376	>	@SuppressWarnings("unchecked") public int reduceToIntSequentially
3377	>	(IntBiFunction<? super K, ? super V> transformer,
3378	>	int basis,
3379	>	IntBinaryOperator reducer) {
3380	>	if (transformer == null || reducer == null)
3381	>	throw new NullPointerException();
3382	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3383	>	int r = basis; V v;
3384	>	while ((v = it.advance()) != null)
3385	>	r = reducer.applyAsInt(r, transformer.applyAsInt((K)it.nextKey, v));
3386	>	return r;
3387	>	}
3388	>
3389	>	/**
3390	>	* Performs the given action for each key.
3391	>	*
3392	>	* @param action the action
3393	>	*/
3394	>	@SuppressWarnings("unchecked") public void forEachKeySequentially
3395	>	(Block<? super K> action) {
3396	>	if (action == null) throw new NullPointerException();
3397	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3398	>	while (it.advance() != null)
3399	>	action.accept((K)it.nextKey);
3400	>	}
3401	>
3402	>	/**
3403	>	* Performs the given action for each non-null transformation
3404	>	* of each key.
3405	>	*
3406	>	* @param transformer a function returning the transformation
3407	>	* for an element, or null of there is no transformation (in
3408	>	* which case the action is not applied).
3409	>	* @param action the action
3410	>	*/
3411	>	@SuppressWarnings("unchecked") public <U> void forEachKeySequentially
3412	>	(Function<? super K, ? extends U> transformer,
3413	>	Block<? super U> action) {
3414	>	if (transformer == null || action == null)
3415	>	throw new NullPointerException();
3416	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3417	>	U u;
3418	>	while (it.advance() != null) {
3419	>	if ((u = transformer.apply((K)it.nextKey)) != null)
3420	>	action.accept(u);
3421		}
3422	<	public boolean isEmpty() {
3423	<	return ConcurrentHashMap.this.isEmpty();
3422	>	ForkJoinTasks.forEachKey
3423	>	(this, transformer, action).invoke();
3424	>	}
3425	>
3426	>	/**
3427	>	* Returns a non-null result from applying the given search
3428	>	* function on each key, or null if none.
3429	>	*
3430	>	* @param searchFunction a function returning a non-null
3431	>	* result on success, else null
3432	>	* @return a non-null result from applying the given search
3433	>	* function on each key, or null if none
3434	>	*/
3435	>	@SuppressWarnings("unchecked") public <U> U searchKeysSequentially
3436	>	(Function<? super K, ? extends U> searchFunction) {
3437	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3438	>	U u;
3439	>	while (it.advance() != null) {
3440	>	if ((u = searchFunction.apply((K)it.nextKey)) != null)
3441	>	return u;
3442		}
3443	<	public boolean contains(Object o) {
3444	<	return ConcurrentHashMap.this.containsValue(o);
3443	>	return null;
3444	>	}
3445	>
3446	>	/**
3447	>	* Returns the result of accumulating all keys using the given
3448	>	* reducer to combine values, or null if none.
3449	>	*
3450	>	* @param reducer a commutative associative combining function
3451	>	* @return the result of accumulating all keys using the given
3452	>	* reducer to combine values, or null if none
3453	>	*/
3454	>	@SuppressWarnings("unchecked") public K reduceKeysSequentially
3455	>	(BiFunction<? super K, ? super K, ? extends K> reducer) {
3456	>	if (reducer == null) throw new NullPointerException();
3457	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3458	>	K r = null;
3459	>	while (it.advance() != null) {
3460	>	K u = (K)it.nextKey;
3461	>	r = (r == null) ? u : reducer.apply(r, u);
3462	>	}
3463	>	return r;
3464	>	}
3465	>
3466	>	/**
3467	>	* Returns the result of accumulating the given transformation
3468	>	* of all keys using the given reducer to combine values, or
3469	>	* null if none.
3470	>	*
3471	>	* @param transformer a function returning the transformation
3472	>	* for an element, or null of there is no transformation (in
3473	>	* which case it is not combined).
3474	>	* @param reducer a commutative associative combining function
3475	>	* @return the result of accumulating the given transformation
3476	>	* of all keys
3477	>	*/
3478	>	@SuppressWarnings("unchecked") public <U> U reduceKeysSequentially
3479	>	(Function<? super K, ? extends U> transformer,
3480	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3481	>	if (transformer == null || reducer == null)
3482	>	throw new NullPointerException();
3483	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3484	>	U r = null, u;
3485	>	while (it.advance() != null) {
3486	>	if ((u = transformer.apply((K)it.nextKey)) != null)
3487	>	r = (r == null) ? u : reducer.apply(r, u);
3488		}
3489	<	public void clear() {
3490	<	ConcurrentHashMap.this.clear();
3489	>	return r;
3490	>	}
3491	>
3492	>	/**
3493	>	* Returns the result of accumulating the given transformation
3494	>	* of all keys using the given reducer to combine values, and
3495	>	* the given basis as an identity value.
3496	>	*
3497	>	* @param transformer a function returning the transformation
3498	>	* for an element
3499	>	* @param basis the identity (initial default value) for the reduction
3500	>	* @param reducer a commutative associative combining function
3501	>	* @return the result of accumulating the given transformation
3502	>	* of all keys
3503	>	*/
3504	>	@SuppressWarnings("unchecked") public double reduceKeysToDoubleSequentially
3505	>	(DoubleFunction<? super K> transformer,
3506	>	double basis,
3507	>	DoubleBinaryOperator reducer) {
3508	>	if (transformer == null || reducer == null)
3509	>	throw new NullPointerException();
3510	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3511	>	double r = basis;
3512	>	while (it.advance() != null)
3513	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble((K)it.nextKey));
3514	>	return r;
3515	>	}
3516	>
3517	>	/**
3518	>	* Returns the result of accumulating the given transformation
3519	>	* of all keys using the given reducer to combine values, and
3520	>	* the given basis as an identity value.
3521	>	*
3522	>	* @param transformer a function returning the transformation
3523	>	* for an element
3524	>	* @param basis the identity (initial default value) for the reduction
3525	>	* @param reducer a commutative associative combining function
3526	>	* @return the result of accumulating the given transformation
3527	>	* of all keys
3528	>	*/
3529	>	@SuppressWarnings("unchecked") public long reduceKeysToLongSequentially
3530	>	(LongFunction<? super K> transformer,
3531	>	long basis,
3532	>	LongBinaryOperator reducer) {
3533	>	if (transformer == null || reducer == null)
3534	>	throw new NullPointerException();
3535	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3536	>	long r = basis;
3537	>	while (it.advance() != null)
3538	>	r = reducer.applyAsLong(r, transformer.applyAsLong((K)it.nextKey));
3539	>	return r;
3540	>	}
3541	>
3542	>	/**
3543	>	* Returns the result of accumulating the given transformation
3544	>	* of all keys using the given reducer to combine values, and
3545	>	* the given basis as an identity value.
3546	>	*
3547	>	* @param transformer a function returning the transformation
3548	>	* for an element
3549	>	* @param basis the identity (initial default value) for the reduction
3550	>	* @param reducer a commutative associative combining function
3551	>	* @return the result of accumulating the given transformation
3552	>	* of all keys
3553	>	*/
3554	>	@SuppressWarnings("unchecked") public int reduceKeysToIntSequentially
3555	>	(IntFunction<? super K> transformer,
3556	>	int basis,
3557	>	IntBinaryOperator reducer) {
3558	>	if (transformer == null || reducer == null)
3559	>	throw new NullPointerException();
3560	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3561	>	int r = basis;
3562	>	while (it.advance() != null)
3563	>	r = reducer.applyAsInt(r, transformer.applyAsInt((K)it.nextKey));
3564	>	return r;
3565	>	}
3566	>
3567	>	/**
3568	>	* Performs the given action for each value.
3569	>	*
3570	>	* @param action the action
3571	>	*/
3572	>	public void forEachValueSequentially(Block<? super V> action) {
3573	>	if (action == null) throw new NullPointerException();
3574	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3575	>	V v;
3576	>	while ((v = it.advance()) != null)
3577	>	action.accept(v);
3578	>	}
3579	>
3580	>	/**
3581	>	* Performs the given action for each non-null transformation
3582	>	* of each value.
3583	>	*
3584	>	* @param transformer a function returning the transformation
3585	>	* for an element, or null of there is no transformation (in
3586	>	* which case the action is not applied).
3587	>	*/
3588	>	public <U> void forEachValueSequentially
3589	>	(Function<? super V, ? extends U> transformer,
3590	>	Block<? super U> action) {
3591	>	if (transformer == null || action == null)
3592	>	throw new NullPointerException();
3593	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3594	>	V v; U u;
3595	>	while ((v = it.advance()) != null) {
3596	>	if ((u = transformer.apply(v)) != null)
3597	>	action.accept(u);
3598		}
3599		}
3600
3601	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
3602	<	public Iterator<Map.Entry<K,V>> iterator() {
3603	<	return new EntryIterator();
3601	>	/**
3602	>	* Returns a non-null result from applying the given search
3603	>	* function on each value, or null if none.
3604	>	*
3605	>	* @param searchFunction a function returning a non-null
3606	>	* result on success, else null
3607	>	* @return a non-null result from applying the given search
3608	>	* function on each value, or null if none
3609	>	*/
3610	>	public <U> U searchValuesSequentially
3611	>	(Function<? super V, ? extends U> searchFunction) {
3612	>	if (searchFunction == null) throw new NullPointerException();
3613	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3614	>	V v; U u;
3615	>	while ((v = it.advance()) != null) {
3616	>	if ((u = searchFunction.apply(v)) != null)
3617	>	return u;
3618		}
3619	<	public boolean contains(Object o) {
3620	<	if (!(o instanceof Map.Entry))
3621	<	return false;
3622	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3623	<	V v = ConcurrentHashMap.this.get(e.getKey());
3624	<	return v != null && v.equals(e.getValue());
3619	>	return null;
3620	>	}
3621	>
3622	>	/**
3623	>	* Returns the result of accumulating all values using the
3624	>	* given reducer to combine values, or null if none.
3625	>	*
3626	>	* @param reducer a commutative associative combining function
3627	>	* @return the result of accumulating all values
3628	>	*/
3629	>	public V reduceValuesSequentially
3630	>	(BiFunction<? super V, ? super V, ? extends V> reducer) {
3631	>	if (reducer == null) throw new NullPointerException();
3632	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3633	>	V r = null; V v;
3634	>	while ((v = it.advance()) != null)
3635	>	r = (r == null) ? v : reducer.apply(r, v);
3636	>	return r;
3637	>	}
3638	>
3639	>	/**
3640	>	* Returns the result of accumulating the given transformation
3641	>	* of all values using the given reducer to combine values, or
3642	>	* null if none.
3643	>	*
3644	>	* @param transformer a function returning the transformation
3645	>	* for an element, or null of there is no transformation (in
3646	>	* which case it is not combined).
3647	>	* @param reducer a commutative associative combining function
3648	>	* @return the result of accumulating the given transformation
3649	>	* of all values
3650	>	*/
3651	>	public <U> U reduceValuesSequentially
3652	>	(Function<? super V, ? extends U> transformer,
3653	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3654	>	if (transformer == null || reducer == null)
3655	>	throw new NullPointerException();
3656	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3657	>	U r = null, u; V v;
3658	>	while ((v = it.advance()) != null) {
3659	>	if ((u = transformer.apply(v)) != null)
3660	>	r = (r == null) ? u : reducer.apply(r, u);
3661		}
3662	<	public boolean remove(Object o) {
3663	<	if (!(o instanceof Map.Entry))
3664	<	return false;
3665	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3666	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
3662	>	return r;
3663	>	}
3664	>
3665	>	/**
3666	>	* Returns the result of accumulating the given transformation
3667	>	* of all values using the given reducer to combine values,
3668	>	* and the given basis as an identity value.
3669	>	*
3670	>	* @param transformer a function returning the transformation
3671	>	* for an element
3672	>	* @param basis the identity (initial default value) for the reduction
3673	>	* @param reducer a commutative associative combining function
3674	>	* @return the result of accumulating the given transformation
3675	>	* of all values
3676	>	*/
3677	>	public double reduceValuesToDoubleSequentially
3678	>	(DoubleFunction<? super V> transformer,
3679	>	double basis,
3680	>	DoubleBinaryOperator reducer) {
3681	>	if (transformer == null || reducer == null)
3682	>	throw new NullPointerException();
3683	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3684	>	double r = basis; V v;
3685	>	while ((v = it.advance()) != null)
3686	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(v));
3687	>	return r;
3688	>	}
3689	>
3690	>	/**
3691	>	* Returns the result of accumulating the given transformation
3692	>	* of all values using the given reducer to combine values,
3693	>	* and the given basis as an identity value.
3694	>	*
3695	>	* @param transformer a function returning the transformation
3696	>	* for an element
3697	>	* @param basis the identity (initial default value) for the reduction
3698	>	* @param reducer a commutative associative combining function
3699	>	* @return the result of accumulating the given transformation
3700	>	* of all values
3701	>	*/
3702	>	public long reduceValuesToLongSequentially
3703	>	(LongFunction<? super V> transformer,
3704	>	long basis,
3705	>	LongBinaryOperator reducer) {
3706	>	if (transformer == null || reducer == null)
3707	>	throw new NullPointerException();
3708	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3709	>	long r = basis; V v;
3710	>	while ((v = it.advance()) != null)
3711	>	r = reducer.applyAsLong(r, transformer.applyAsLong(v));
3712	>	return r;
3713	>	}
3714	>
3715	>	/**
3716	>	* Returns the result of accumulating the given transformation
3717	>	* of all values using the given reducer to combine values,
3718	>	* and the given basis as an identity value.
3719	>	*
3720	>	* @param transformer a function returning the transformation
3721	>	* for an element
3722	>	* @param basis the identity (initial default value) for the reduction
3723	>	* @param reducer a commutative associative combining function
3724	>	* @return the result of accumulating the given transformation
3725	>	* of all values
3726	>	*/
3727	>	public int reduceValuesToIntSequentially
3728	>	(IntFunction<? super V> transformer,
3729	>	int basis,
3730	>	IntBinaryOperator reducer) {
3731	>	if (transformer == null || reducer == null)
3732	>	throw new NullPointerException();
3733	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3734	>	int r = basis; V v;
3735	>	while ((v = it.advance()) != null)
3736	>	r = reducer.applyAsInt(r, transformer.applyAsInt(v));
3737	>	return r;
3738	>	}
3739	>
3740	>	/**
3741	>	* Performs the given action for each entry.
3742	>	*
3743	>	* @param action the action
3744	>	*/
3745	>	@SuppressWarnings("unchecked") public void forEachEntrySequentially
3746	>	(Block<? super Map.Entry<K,V>> action) {
3747	>	if (action == null) throw new NullPointerException();
3748	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3749	>	V v;
3750	>	while ((v = it.advance()) != null)
3751	>	action.accept(entryFor((K)it.nextKey, v));
3752	>	}
3753	>
3754	>	/**
3755	>	* Performs the given action for each non-null transformation
3756	>	* of each entry.
3757	>	*
3758	>	* @param transformer a function returning the transformation
3759	>	* for an element, or null of there is no transformation (in
3760	>	* which case the action is not applied).
3761	>	* @param action the action
3762	>	*/
3763	>	@SuppressWarnings("unchecked") public <U> void forEachEntrySequentially
3764	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
3765	>	Block<? super U> action) {
3766	>	if (transformer == null || action == null)
3767	>	throw new NullPointerException();
3768	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3769	>	V v; U u;
3770	>	while ((v = it.advance()) != null) {
3771	>	if ((u = transformer.apply(entryFor((K)it.nextKey, v))) != null)
3772	>	action.accept(u);
3773		}
3774	<	public int size() {
3775	<	return ConcurrentHashMap.this.size();
3774	>	}
3775	>
3776	>	/**
3777	>	* Returns a non-null result from applying the given search
3778	>	* function on each entry, or null if none.
3779	>	*
3780	>	* @param searchFunction a function returning a non-null
3781	>	* result on success, else null
3782	>	* @return a non-null result from applying the given search
3783	>	* function on each entry, or null if none
3784	>	*/
3785	>	@SuppressWarnings("unchecked") public <U> U searchEntriesSequentially
3786	>	(Function<Map.Entry<K,V>, ? extends U> searchFunction) {
3787	>	if (searchFunction == null) throw new NullPointerException();
3788	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3789	>	V v; U u;
3790	>	while ((v = it.advance()) != null) {
3791	>	if ((u = searchFunction.apply(entryFor((K)it.nextKey, v))) != null)
3792	>	return u;
3793		}
3794	<	public boolean isEmpty() {
3795	<	return ConcurrentHashMap.this.isEmpty();
3794	>	return null;
3795	>	}
3796	>
3797	>	/**
3798	>	* Returns the result of accumulating all entries using the
3799	>	* given reducer to combine values, or null if none.
3800	>	*
3801	>	* @param reducer a commutative associative combining function
3802	>	* @return the result of accumulating all entries
3803	>	*/
3804	>	@SuppressWarnings("unchecked") public Map.Entry<K,V> reduceEntriesSequentially
3805	>	(BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
3806	>	if (reducer == null) throw new NullPointerException();
3807	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3808	>	Map.Entry<K,V> r = null; V v;
3809	>	while ((v = it.advance()) != null) {
3810	>	Map.Entry<K,V> u = entryFor((K)it.nextKey, v);
3811	>	r = (r == null) ? u : reducer.apply(r, u);
3812		}
3813	<	public void clear() {
3814	<	ConcurrentHashMap.this.clear();
3813	>	return r;
3814	>	}
3815	>
3816	>	/**
3817	>	* Returns the result of accumulating the given transformation
3818	>	* of all entries using the given reducer to combine values,
3819	>	* or null if none.
3820	>	*
3821	>	* @param transformer a function returning the transformation
3822	>	* for an element, or null of there is no transformation (in
3823	>	* which case it is not combined).
3824	>	* @param reducer a commutative associative combining function
3825	>	* @return the result of accumulating the given transformation
3826	>	* of all entries
3827	>	*/
3828	>	@SuppressWarnings("unchecked") public <U> U reduceEntriesSequentially
3829	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
3830	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3831	>	if (transformer == null || reducer == null)
3832	>	throw new NullPointerException();
3833	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3834	>	U r = null, u; V v;
3835	>	while ((v = it.advance()) != null) {
3836	>	if ((u = transformer.apply(entryFor((K)it.nextKey, v))) != null)
3837	>	r = (r == null) ? u : reducer.apply(r, u);
3838		}
3839	+	return r;
3840		}
3841
3842	<	/* ---------------- Serialization Support -------------- */
3842	>	/**
3843	>	* Returns the result of accumulating the given transformation
3844	>	* of all entries using the given reducer to combine values,
3845	>	* and the given basis as an identity value.
3846	>	*
3847	>	* @param transformer a function returning the transformation
3848	>	* for an element
3849	>	* @param basis the identity (initial default value) for the reduction
3850	>	* @param reducer a commutative associative combining function
3851	>	* @return the result of accumulating the given transformation
3852	>	* of all entries
3853	>	*/
3854	>	@SuppressWarnings("unchecked") public double reduceEntriesToDoubleSequentially
3855	>	(DoubleFunction<Map.Entry<K,V>> transformer,
3856	>	double basis,
3857	>	DoubleBinaryOperator reducer) {
3858	>	if (transformer == null || reducer == null)
3859	>	throw new NullPointerException();
3860	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3861	>	double r = basis; V v;
3862	>	while ((v = it.advance()) != null)
3863	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(entryFor((K)it.nextKey, v)));
3864	>	return r;
3865	>	}
3866
3867		/**
3868	<	* Saves the state of the <tt>ConcurrentHashMap</tt> instance to a
3869	<	* stream (i.e., serializes it).
3870	<	* @param s the stream
3871	<	* @serialData
3872	<	* the key (Object) and value (Object)
3873	<	* for each key-value mapping, followed by a null pair.
3874	<	* The key-value mappings are emitted in no particular order.
3868	>	* Returns the result of accumulating the given transformation
3869	>	* of all entries using the given reducer to combine values,
3870	>	* and the given basis as an identity value.
3871	>	*
3872	>	* @param transformer a function returning the transformation
3873	>	* for an element
3874	>	* @param basis the identity (initial default value) for the reduction
3875	>	* @param reducer a commutative associative combining function
3876	>	* @return the result of accumulating the given transformation
3877	>	* of all entries
3878	>	*/
3879	>	@SuppressWarnings("unchecked") public long reduceEntriesToLongSequentially
3880	>	(LongFunction<Map.Entry<K,V>> transformer,
3881	>	long basis,
3882	>	LongBinaryOperator reducer) {
3883	>	if (transformer == null || reducer == null)
3884	>	throw new NullPointerException();
3885	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3886	>	long r = basis; V v;
3887	>	while ((v = it.advance()) != null)
3888	>	r = reducer.applyAsLong(r, transformer.applyAsLong(entryFor((K)it.nextKey, v)));
3889	>	return r;
3890	>	}
3891	>
3892	>	/**
3893	>	* Returns the result of accumulating the given transformation
3894	>	* of all entries using the given reducer to combine values,
3895	>	* and the given basis as an identity value.
3896	>	*
3897	>	* @param transformer a function returning the transformation
3898	>	* for an element
3899	>	* @param basis the identity (initial default value) for the reduction
3900	>	* @param reducer a commutative associative combining function
3901	>	* @return the result of accumulating the given transformation
3902	>	* of all entries
3903	>	*/
3904	>	@SuppressWarnings("unchecked") public int reduceEntriesToIntSequentially
3905	>	(IntFunction<Map.Entry<K,V>> transformer,
3906	>	int basis,
3907	>	IntBinaryOperator reducer) {
3908	>	if (transformer == null || reducer == null)
3909	>	throw new NullPointerException();
3910	>	Traverser<K,V,Object> it = new Traverser<K,V,Object>(this);
3911	>	int r = basis; V v;
3912	>	while ((v = it.advance()) != null)
3913	>	r = reducer.applyAsInt(r, transformer.applyAsInt(entryFor((K)it.nextKey, v)));
3914	>	return r;
3915	>	}
3916	>
3917	>	// Parallel bulk operations
3918	>
3919	>	/**
3920	>	* Performs the given action for each (key, value).
3921	>	*
3922	>	* @param action the action
3923		*/
3924	<	private void writeObject(java.io.ObjectOutputStream s)
3925	<	throws java.io.IOException {
3926	<	// force all segments for serialization compatibility
3927	<	for (int k = 0; k < segments.length; ++k)
1404	<	ensureSegment(k);
1405	<	s.defaultWriteObject();
3924	>	public void forEachInParallel(BiBlock<? super K,? super V> action) {
3925	>	ForkJoinTasks.forEach
3926	>	(this, action).invoke();
3927	>	}
3928
3929	<	final Segment<K,V>[] segments = this.segments;
3930	<	for (int k = 0; k < segments.length; ++k) {
3931	<	Segment<K,V> seg = segmentAt(segments, k);
3932	<	seg.lock();
3933	<	try {
3934	<	HashEntry<K,V>[] tab = seg.table;
3935	<	for (int i = 0; i < tab.length; ++i) {
3936	<	HashEntry<K,V> e;
3937	<	for (e = entryAt(tab, i); e != null; e = e.next) {
3938	<	s.writeObject(e.key);
3939	<	s.writeObject(e.value);
3929	>	/**
3930	>	* Performs the given action for each non-null transformation
3931	>	* of each (key, value).
3932	>	*
3933	>	* @param transformer a function returning the transformation
3934	>	* for an element, or null of there is no transformation (in
3935	>	* which case the action is not applied).
3936	>	* @param action the action
3937	>	*/
3938	>	public <U> void forEachInParallel
3939	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3940	>	Block<? super U> action) {
3941	>	ForkJoinTasks.forEach
3942	>	(this, transformer, action).invoke();
3943	>	}
3944	>
3945	>	/**
3946	>	* Returns a non-null result from applying the given search
3947	>	* function on each (key, value), or null if none.  Upon
3948	>	* success, further element processing is suppressed and the
3949	>	* results of any other parallel invocations of the search
3950	>	* function are ignored.
3951	>	*
3952	>	* @param searchFunction a function returning a non-null
3953	>	* result on success, else null
3954	>	* @return a non-null result from applying the given search
3955	>	* function on each (key, value), or null if none
3956	>	*/
3957	>	public <U> U searchInParallel
3958	>	(BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3959	>	return ForkJoinTasks.search
3960	>	(this, searchFunction).invoke();
3961	>	}
3962	>
3963	>	/**
3964	>	* Returns the result of accumulating the given transformation
3965	>	* of all (key, value) pairs using the given reducer to
3966	>	* combine values, or null if none.
3967	>	*
3968	>	* @param transformer a function returning the transformation
3969	>	* for an element, or null of there is no transformation (in
3970	>	* which case it is not combined).
3971	>	* @param reducer a commutative associative combining function
3972	>	* @return the result of accumulating the given transformation
3973	>	* of all (key, value) pairs
3974	>	*/
3975	>	public <U> U reduceInParallel
3976	>	(BiFunction<? super K, ? super V, ? extends U> transformer,
3977	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3978	>	return ForkJoinTasks.reduce
3979	>	(this, transformer, reducer).invoke();
3980	>	}
3981	>
3982	>	/**
3983	>	* Returns the result of accumulating the given transformation
3984	>	* of all (key, value) pairs using the given reducer to
3985	>	* combine values, and the given basis as an identity value.
3986	>	*
3987	>	* @param transformer a function returning the transformation
3988	>	* for an element
3989	>	* @param basis the identity (initial default value) for the reduction
3990	>	* @param reducer a commutative associative combining function
3991	>	* @return the result of accumulating the given transformation
3992	>	* of all (key, value) pairs
3993	>	*/
3994	>	public double reduceToDoubleInParallel
3995	>	(DoubleBiFunction<? super K, ? super V> transformer,
3996	>	double basis,
3997	>	DoubleBinaryOperator reducer) {
3998	>	return ForkJoinTasks.reduceToDouble
3999	>	(this, transformer, basis, reducer).invoke();
4000	>	}
4001	>
4002	>	/**
4003	>	* Returns the result of accumulating the given transformation
4004	>	* of all (key, value) pairs using the given reducer to
4005	>	* combine values, and the given basis as an identity value.
4006	>	*
4007	>	* @param transformer a function returning the transformation
4008	>	* for an element
4009	>	* @param basis the identity (initial default value) for the reduction
4010	>	* @param reducer a commutative associative combining function
4011	>	* @return the result of accumulating the given transformation
4012	>	* of all (key, value) pairs
4013	>	*/
4014	>	public long reduceToLongInParallel
4015	>	(LongBiFunction<? super K, ? super V> transformer,
4016	>	long basis,
4017	>	LongBinaryOperator reducer) {
4018	>	return ForkJoinTasks.reduceToLong
4019	>	(this, transformer, basis, reducer).invoke();
4020	>	}
4021	>
4022	>	/**
4023	>	* Returns the result of accumulating the given transformation
4024	>	* of all (key, value) pairs using the given reducer to
4025	>	* combine values, and the given basis as an identity value.
4026	>	*
4027	>	* @param transformer a function returning the transformation
4028	>	* for an element
4029	>	* @param basis the identity (initial default value) for the reduction
4030	>	* @param reducer a commutative associative combining function
4031	>	* @return the result of accumulating the given transformation
4032	>	* of all (key, value) pairs
4033	>	*/
4034	>	public int reduceToIntInParallel
4035	>	(IntBiFunction<? super K, ? super V> transformer,
4036	>	int basis,
4037	>	IntBinaryOperator reducer) {
4038	>	return ForkJoinTasks.reduceToInt
4039	>	(this, transformer, basis, reducer).invoke();
4040	>	}
4041	>
4042	>	/**
4043	>	* Performs the given action for each key.
4044	>	*
4045	>	* @param action the action
4046	>	*/
4047	>	public void forEachKeyInParallel(Block<? super K> action) {
4048	>	ForkJoinTasks.forEachKey
4049	>	(this, action).invoke();
4050	>	}
4051	>
4052	>	/**
4053	>	* Performs the given action for each non-null transformation
4054	>	* of each key.
4055	>	*
4056	>	* @param transformer a function returning the transformation
4057	>	* for an element, or null of there is no transformation (in
4058	>	* which case the action is not applied).
4059	>	* @param action the action
4060	>	*/
4061	>	public <U> void forEachKeyInParallel
4062	>	(Function<? super K, ? extends U> transformer,
4063	>	Block<? super U> action) {
4064	>	ForkJoinTasks.forEachKey
4065	>	(this, transformer, action).invoke();
4066	>	}
4067	>
4068	>	/**
4069	>	* Returns a non-null result from applying the given search
4070	>	* function on each key, or null if none. Upon success,
4071	>	* further element processing is suppressed and the results of
4072	>	* any other parallel invocations of the search function are
4073	>	* ignored.
4074	>	*
4075	>	* @param searchFunction a function returning a non-null
4076	>	* result on success, else null
4077	>	* @return a non-null result from applying the given search
4078	>	* function on each key, or null if none
4079	>	*/
4080	>	public <U> U searchKeysInParallel
4081	>	(Function<? super K, ? extends U> searchFunction) {
4082	>	return ForkJoinTasks.searchKeys
4083	>	(this, searchFunction).invoke();
4084	>	}
4085	>
4086	>	/**
4087	>	* Returns the result of accumulating all keys using the given
4088	>	* reducer to combine values, or null if none.
4089	>	*
4090	>	* @param reducer a commutative associative combining function
4091	>	* @return the result of accumulating all keys using the given
4092	>	* reducer to combine values, or null if none
4093	>	*/
4094	>	public K reduceKeysInParallel
4095	>	(BiFunction<? super K, ? super K, ? extends K> reducer) {
4096	>	return ForkJoinTasks.reduceKeys
4097	>	(this, reducer).invoke();
4098	>	}
4099	>
4100	>	/**
4101	>	* Returns the result of accumulating the given transformation
4102	>	* of all keys using the given reducer to combine values, or
4103	>	* null if none.
4104	>	*
4105	>	* @param transformer a function returning the transformation
4106	>	* for an element, or null of there is no transformation (in
4107	>	* which case it is not combined).
4108	>	* @param reducer a commutative associative combining function
4109	>	* @return the result of accumulating the given transformation
4110	>	* of all keys
4111	>	*/
4112	>	public <U> U reduceKeysInParallel
4113	>	(Function<? super K, ? extends U> transformer,
4114	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4115	>	return ForkJoinTasks.reduceKeys
4116	>	(this, transformer, reducer).invoke();
4117	>	}
4118	>
4119	>	/**
4120	>	* Returns the result of accumulating the given transformation
4121	>	* of all keys using the given reducer to combine values, and
4122	>	* the given basis as an identity value.
4123	>	*
4124	>	* @param transformer a function returning the transformation
4125	>	* for an element
4126	>	* @param basis the identity (initial default value) for the reduction
4127	>	* @param reducer a commutative associative combining function
4128	>	* @return the result of accumulating the given transformation
4129	>	* of all keys
4130	>	*/
4131	>	public double reduceKeysToDoubleInParallel
4132	>	(DoubleFunction<? super K> transformer,
4133	>	double basis,
4134	>	DoubleBinaryOperator reducer) {
4135	>	return ForkJoinTasks.reduceKeysToDouble
4136	>	(this, transformer, basis, reducer).invoke();
4137	>	}
4138	>
4139	>	/**
4140	>	* Returns the result of accumulating the given transformation
4141	>	* of all keys using the given reducer to combine values, and
4142	>	* the given basis as an identity value.
4143	>	*
4144	>	* @param transformer a function returning the transformation
4145	>	* for an element
4146	>	* @param basis the identity (initial default value) for the reduction
4147	>	* @param reducer a commutative associative combining function
4148	>	* @return the result of accumulating the given transformation
4149	>	* of all keys
4150	>	*/
4151	>	public long reduceKeysToLongInParallel
4152	>	(LongFunction<? super K> transformer,
4153	>	long basis,
4154	>	LongBinaryOperator reducer) {
4155	>	return ForkJoinTasks.reduceKeysToLong
4156	>	(this, transformer, basis, reducer).invoke();
4157	>	}
4158	>
4159	>	/**
4160	>	* Returns the result of accumulating the given transformation
4161	>	* of all keys using the given reducer to combine values, and
4162	>	* the given basis as an identity value.
4163	>	*
4164	>	* @param transformer a function returning the transformation
4165	>	* for an element
4166	>	* @param basis the identity (initial default value) for the reduction
4167	>	* @param reducer a commutative associative combining function
4168	>	* @return the result of accumulating the given transformation
4169	>	* of all keys
4170	>	*/
4171	>	public int reduceKeysToIntInParallel
4172	>	(IntFunction<? super K> transformer,
4173	>	int basis,
4174	>	IntBinaryOperator reducer) {
4175	>	return ForkJoinTasks.reduceKeysToInt
4176	>	(this, transformer, basis, reducer).invoke();
4177	>	}
4178	>
4179	>	/**
4180	>	* Performs the given action for each value.
4181	>	*
4182	>	* @param action the action
4183	>	*/
4184	>	public void forEachValueInParallel(Block<? super V> action) {
4185	>	ForkJoinTasks.forEachValue
4186	>	(this, action).invoke();
4187	>	}
4188	>
4189	>	/**
4190	>	* Performs the given action for each non-null transformation
4191	>	* of each value.
4192	>	*
4193	>	* @param transformer a function returning the transformation
4194	>	* for an element, or null of there is no transformation (in
4195	>	* which case the action is not applied).
4196	>	*/
4197	>	public <U> void forEachValueInParallel
4198	>	(Function<? super V, ? extends U> transformer,
4199	>	Block<? super U> action) {
4200	>	ForkJoinTasks.forEachValue
4201	>	(this, transformer, action).invoke();
4202	>	}
4203	>
4204	>	/**
4205	>	* Returns a non-null result from applying the given search
4206	>	* function on each value, or null if none.  Upon success,
4207	>	* further element processing is suppressed and the results of
4208	>	* any other parallel invocations of the search function are
4209	>	* ignored.
4210	>	*
4211	>	* @param searchFunction a function returning a non-null
4212	>	* result on success, else null
4213	>	* @return a non-null result from applying the given search
4214	>	* function on each value, or null if none
4215	>	*/
4216	>	public <U> U searchValuesInParallel
4217	>	(Function<? super V, ? extends U> searchFunction) {
4218	>	return ForkJoinTasks.searchValues
4219	>	(this, searchFunction).invoke();
4220	>	}
4221	>
4222	>	/**
4223	>	* Returns the result of accumulating all values using the
4224	>	* given reducer to combine values, or null if none.
4225	>	*
4226	>	* @param reducer a commutative associative combining function
4227	>	* @return the result of accumulating all values
4228	>	*/
4229	>	public V reduceValuesInParallel
4230	>	(BiFunction<? super V, ? super V, ? extends V> reducer) {
4231	>	return ForkJoinTasks.reduceValues
4232	>	(this, reducer).invoke();
4233	>	}
4234	>
4235	>	/**
4236	>	* Returns the result of accumulating the given transformation
4237	>	* of all values using the given reducer to combine values, or
4238	>	* null if none.
4239	>	*
4240	>	* @param transformer a function returning the transformation
4241	>	* for an element, or null of there is no transformation (in
4242	>	* which case it is not combined).
4243	>	* @param reducer a commutative associative combining function
4244	>	* @return the result of accumulating the given transformation
4245	>	* of all values
4246	>	*/
4247	>	public <U> U reduceValuesInParallel
4248	>	(Function<? super V, ? extends U> transformer,
4249	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4250	>	return ForkJoinTasks.reduceValues
4251	>	(this, transformer, reducer).invoke();
4252	>	}
4253	>
4254	>	/**
4255	>	* Returns the result of accumulating the given transformation
4256	>	* of all values using the given reducer to combine values,
4257	>	* and the given basis as an identity value.
4258	>	*
4259	>	* @param transformer a function returning the transformation
4260	>	* for an element
4261	>	* @param basis the identity (initial default value) for the reduction
4262	>	* @param reducer a commutative associative combining function
4263	>	* @return the result of accumulating the given transformation
4264	>	* of all values
4265	>	*/
4266	>	public double reduceValuesToDoubleInParallel
4267	>	(DoubleFunction<? super V> transformer,
4268	>	double basis,
4269	>	DoubleBinaryOperator reducer) {
4270	>	return ForkJoinTasks.reduceValuesToDouble
4271	>	(this, transformer, basis, reducer).invoke();
4272	>	}
4273	>
4274	>	/**
4275	>	* Returns the result of accumulating the given transformation
4276	>	* of all values using the given reducer to combine values,
4277	>	* and the given basis as an identity value.
4278	>	*
4279	>	* @param transformer a function returning the transformation
4280	>	* for an element
4281	>	* @param basis the identity (initial default value) for the reduction
4282	>	* @param reducer a commutative associative combining function
4283	>	* @return the result of accumulating the given transformation
4284	>	* of all values
4285	>	*/
4286	>	public long reduceValuesToLongInParallel
4287	>	(LongFunction<? super V> transformer,
4288	>	long basis,
4289	>	LongBinaryOperator reducer) {
4290	>	return ForkJoinTasks.reduceValuesToLong
4291	>	(this, transformer, basis, reducer).invoke();
4292	>	}
4293	>
4294	>	/**
4295	>	* Returns the result of accumulating the given transformation
4296	>	* of all values using the given reducer to combine values,
4297	>	* and the given basis as an identity value.
4298	>	*
4299	>	* @param transformer a function returning the transformation
4300	>	* for an element
4301	>	* @param basis the identity (initial default value) for the reduction
4302	>	* @param reducer a commutative associative combining function
4303	>	* @return the result of accumulating the given transformation
4304	>	* of all values
4305	>	*/
4306	>	public int reduceValuesToIntInParallel
4307	>	(IntFunction<? super V> transformer,
4308	>	int basis,
4309	>	IntBinaryOperator reducer) {
4310	>	return ForkJoinTasks.reduceValuesToInt
4311	>	(this, transformer, basis, reducer).invoke();
4312	>	}
4313	>
4314	>	/**
4315	>	* Performs the given action for each entry.
4316	>	*
4317	>	* @param action the action
4318	>	*/
4319	>	public void forEachEntryInParallel(Block<? super Map.Entry<K,V>> action) {
4320	>	ForkJoinTasks.forEachEntry
4321	>	(this, action).invoke();
4322	>	}
4323	>
4324	>	/**
4325	>	* Performs the given action for each non-null transformation
4326	>	* of each entry.
4327	>	*
4328	>	* @param transformer a function returning the transformation
4329	>	* for an element, or null of there is no transformation (in
4330	>	* which case the action is not applied).
4331	>	* @param action the action
4332	>	*/
4333	>	public <U> void forEachEntryInParallel
4334	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
4335	>	Block<? super U> action) {
4336	>	ForkJoinTasks.forEachEntry
4337	>	(this, transformer, action).invoke();
4338	>	}
4339	>
4340	>	/**
4341	>	* Returns a non-null result from applying the given search
4342	>	* function on each entry, or null if none.  Upon success,
4343	>	* further element processing is suppressed and the results of
4344	>	* any other parallel invocations of the search function are
4345	>	* ignored.
4346	>	*
4347	>	* @param searchFunction a function returning a non-null
4348	>	* result on success, else null
4349	>	* @return a non-null result from applying the given search
4350	>	* function on each entry, or null if none
4351	>	*/
4352	>	public <U> U searchEntriesInParallel
4353	>	(Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4354	>	return ForkJoinTasks.searchEntries
4355	>	(this, searchFunction).invoke();
4356	>	}
4357	>
4358	>	/**
4359	>	* Returns the result of accumulating all entries using the
4360	>	* given reducer to combine values, or null if none.
4361	>	*
4362	>	* @param reducer a commutative associative combining function
4363	>	* @return the result of accumulating all entries
4364	>	*/
4365	>	public Map.Entry<K,V> reduceEntriesInParallel
4366	>	(BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4367	>	return ForkJoinTasks.reduceEntries
4368	>	(this, reducer).invoke();
4369	>	}
4370	>
4371	>	/**
4372	>	* Returns the result of accumulating the given transformation
4373	>	* of all entries using the given reducer to combine values,
4374	>	* or null if none.
4375	>	*
4376	>	* @param transformer a function returning the transformation
4377	>	* for an element, or null of there is no transformation (in
4378	>	* which case it is not combined).
4379	>	* @param reducer a commutative associative combining function
4380	>	* @return the result of accumulating the given transformation
4381	>	* of all entries
4382	>	*/
4383	>	public <U> U reduceEntriesInParallel
4384	>	(Function<Map.Entry<K,V>, ? extends U> transformer,
4385	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4386	>	return ForkJoinTasks.reduceEntries
4387	>	(this, transformer, reducer).invoke();
4388	>	}
4389	>
4390	>	/**
4391	>	* Returns the result of accumulating the given transformation
4392	>	* of all entries using the given reducer to combine values,
4393	>	* and the given basis as an identity value.
4394	>	*
4395	>	* @param transformer a function returning the transformation
4396	>	* for an element
4397	>	* @param basis the identity (initial default value) for the reduction
4398	>	* @param reducer a commutative associative combining function
4399	>	* @return the result of accumulating the given transformation
4400	>	* of all entries
4401	>	*/
4402	>	public double reduceEntriesToDoubleInParallel
4403	>	(DoubleFunction<Map.Entry<K,V>> transformer,
4404	>	double basis,
4405	>	DoubleBinaryOperator reducer) {
4406	>	return ForkJoinTasks.reduceEntriesToDouble
4407	>	(this, transformer, basis, reducer).invoke();
4408	>	}
4409	>
4410	>	/**
4411	>	* Returns the result of accumulating the given transformation
4412	>	* of all entries using the given reducer to combine values,
4413	>	* and the given basis as an identity value.
4414	>	*
4415	>	* @param transformer a function returning the transformation
4416	>	* for an element
4417	>	* @param basis the identity (initial default value) for the reduction
4418	>	* @param reducer a commutative associative combining function
4419	>	* @return the result of accumulating the given transformation
4420	>	* of all entries
4421	>	*/
4422	>	public long reduceEntriesToLongInParallel
4423	>	(LongFunction<Map.Entry<K,V>> transformer,
4424	>	long basis,
4425	>	LongBinaryOperator reducer) {
4426	>	return ForkJoinTasks.reduceEntriesToLong
4427	>	(this, transformer, basis, reducer).invoke();
4428	>	}
4429	>
4430	>	/**
4431	>	* Returns the result of accumulating the given transformation
4432	>	* of all entries using the given reducer to combine values,
4433	>	* and the given basis as an identity value.
4434	>	*
4435	>	* @param transformer a function returning the transformation
4436	>	* for an element
4437	>	* @param basis the identity (initial default value) for the reduction
4438	>	* @param reducer a commutative associative combining function
4439	>	* @return the result of accumulating the given transformation
4440	>	* of all entries
4441	>	*/
4442	>	public int reduceEntriesToIntInParallel
4443	>	(IntFunction<Map.Entry<K,V>> transformer,
4444	>	int basis,
4445	>	IntBinaryOperator reducer) {
4446	>	return ForkJoinTasks.reduceEntriesToInt
4447	>	(this, transformer, basis, reducer).invoke();
4448	>	}
4449	>
4450	>
4451	>	/* ----------------Views -------------- */
4452	>
4453	>	/**
4454	>	* Base class for views.
4455	>	*/
4456	>	static abstract class CHMView<K, V> {
4457	>	final ConcurrentHashMap<K, V> map;
4458	>	CHMView(ConcurrentHashMap<K, V> map)  { this.map = map; }
4459	>
4460	>	/**
4461	>	* Returns the map backing this view.
4462	>	*
4463	>	* @return the map backing this view
4464	>	*/
4465	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4466	>
4467	>	public final int size()                 { return map.size(); }
4468	>	public final boolean isEmpty()          { return map.isEmpty(); }
4469	>	public final void clear()               { map.clear(); }
4470	>
4471	>	// implementations below rely on concrete classes supplying these
4472	>	abstract public Iterator<?> iterator();
4473	>	abstract public boolean contains(Object o);
4474	>	abstract public boolean remove(Object o);
4475	>
4476	>	private static final String oomeMsg = "Required array size too large";
4477	>
4478	>	public final Object[] toArray() {
4479	>	long sz = map.mappingCount();
4480	>	if (sz > (long)(MAX_ARRAY_SIZE))
4481	>	throw new OutOfMemoryError(oomeMsg);
4482	>	int n = (int)sz;
4483	>	Object[] r = new Object[n];
4484	>	int i = 0;
4485	>	Iterator<?> it = iterator();
4486	>	while (it.hasNext()) {
4487	>	if (i == n) {
4488	>	if (n >= MAX_ARRAY_SIZE)
4489	>	throw new OutOfMemoryError(oomeMsg);
4490	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4491	>	n = MAX_ARRAY_SIZE;
4492	>	else
4493	>	n += (n >>> 1) + 1;
4494	>	r = Arrays.copyOf(r, n);
4495	>	}
4496	>	r[i++] = it.next();
4497	>	}
4498	>	return (i == n) ? r : Arrays.copyOf(r, i);
4499	>	}
4500	>
4501	>	@SuppressWarnings("unchecked") public final <T> T[] toArray(T[] a) {
4502	>	long sz = map.mappingCount();
4503	>	if (sz > (long)(MAX_ARRAY_SIZE))
4504	>	throw new OutOfMemoryError(oomeMsg);
4505	>	int m = (int)sz;
4506	>	T[] r = (a.length >= m) ? a :
4507	>	(T[])java.lang.reflect.Array
4508	>	.newInstance(a.getClass().getComponentType(), m);
4509	>	int n = r.length;
4510	>	int i = 0;
4511	>	Iterator<?> it = iterator();
4512	>	while (it.hasNext()) {
4513	>	if (i == n) {
4514	>	if (n >= MAX_ARRAY_SIZE)
4515	>	throw new OutOfMemoryError(oomeMsg);
4516	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4517	>	n = MAX_ARRAY_SIZE;
4518	>	else
4519	>	n += (n >>> 1) + 1;
4520	>	r = Arrays.copyOf(r, n);
4521	>	}
4522	>	r[i++] = (T)it.next();
4523	>	}
4524	>	if (a == r && i < n) {
4525	>	r[i] = null; // null-terminate
4526	>	return r;
4527	>	}
4528	>	return (i == n) ? r : Arrays.copyOf(r, i);
4529	>	}
4530	>
4531	>	public final int hashCode() {
4532	>	int h = 0;
4533	>	for (Iterator<?> it = iterator(); it.hasNext();)
4534	>	h += it.next().hashCode();
4535	>	return h;
4536	>	}
4537	>
4538	>	public final String toString() {
4539	>	StringBuilder sb = new StringBuilder();
4540	>	sb.append('[');
4541	>	Iterator<?> it = iterator();
4542	>	if (it.hasNext()) {
4543	>	for (;;) {
4544	>	Object e = it.next();
4545	>	sb.append(e == this ? "(this Collection)" : e);
4546	>	if (!it.hasNext())
4547	>	break;
4548	>	sb.append(',').append(' ');
4549	>	}
4550	>	}
4551	>	return sb.append(']').toString();
4552	>	}
4553	>
4554	>	public final boolean containsAll(Collection<?> c) {
4555	>	if (c != this) {
4556	>	for (Iterator<?> it = c.iterator(); it.hasNext();) {
4557	>	Object e = it.next();
4558	>	if (e == null || !contains(e))
4559	>	return false;
4560	>	}
4561	>	}
4562	>	return true;
4563	>	}
4564	>
4565	>	public final boolean removeAll(Collection<?> c) {
4566	>	boolean modified = false;
4567	>	for (Iterator<?> it = iterator(); it.hasNext();) {
4568	>	if (c.contains(it.next())) {
4569	>	it.remove();
4570	>	modified = true;
4571	>	}
4572	>	}
4573	>	return modified;
4574	>	}
4575	>
4576	>	public final boolean retainAll(Collection<?> c) {
4577	>	boolean modified = false;
4578	>	for (Iterator<?> it = iterator(); it.hasNext();) {
4579	>	if (!c.contains(it.next())) {
4580	>	it.remove();
4581	>	modified = true;
4582	>	}
4583	>	}
4584	>	return modified;
4585	>	}
4586	>
4587	>	}
4588	>
4589	>	/**
4590	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4591	>	* which additions may optionally be enabled by mapping to a
4592	>	* common value.  This class cannot be directly instantiated. See
4593	>	* {@link #keySet}, {@link #keySet(Object)}, {@link #newKeySet()},
4594	>	* {@link #newKeySet(int)}.
4595	>	*/
4596	>	public static class KeySetView<K,V> extends CHMView<K,V>
4597	>	implements Set<K>, java.io.Serializable {
4598	>	private static final long serialVersionUID = 7249069246763182397L;
4599	>	private final V value;
4600	>	KeySetView(ConcurrentHashMap<K, V> map, V value) {  // non-public
4601	>	super(map);
4602	>	this.value = value;
4603	>	}
4604	>
4605	>	/**
4606	>	* Returns the default mapped value for additions,
4607	>	* or {@code null} if additions are not supported.
4608	>	*
4609	>	* @return the default mapped value for additions, or {@code null}
4610	>	* if not supported.
4611	>	*/
4612	>	public V getMappedValue() { return value; }
4613	>
4614	>	// implement Set API
4615	>
4616	>	public boolean contains(Object o) { return map.containsKey(o); }
4617	>	public boolean remove(Object o)   { return map.remove(o) != null; }
4618	>
4619	>	/**
4620	>	* Returns a "weakly consistent" iterator that will never
4621	>	* throw {@link ConcurrentModificationException}, and
4622	>	* guarantees to traverse elements as they existed upon
4623	>	* construction of the iterator, and may (but is not
4624	>	* guaranteed to) reflect any modifications subsequent to
4625	>	* construction.
4626	>	*
4627	>	* @return an iterator over the keys of this map
4628	>	*/
4629	>	public Iterator<K> iterator()     { return new KeyIterator<K,V>(map); }
4630	>	public boolean add(K e) {
4631	>	V v;
4632	>	if ((v = value) == null)
4633	>	throw new UnsupportedOperationException();
4634	>	if (e == null)
4635	>	throw new NullPointerException();
4636	>	return map.internalPut(e, v, true) == null;
4637	>	}
4638	>	public boolean addAll(Collection<? extends K> c) {
4639	>	boolean added = false;
4640	>	V v;
4641	>	if ((v = value) == null)
4642	>	throw new UnsupportedOperationException();
4643	>	for (K e : c) {
4644	>	if (e == null)
4645	>	throw new NullPointerException();
4646	>	if (map.internalPut(e, v, true) == null)
4647	>	added = true;
4648	>	}
4649	>	return added;
4650	>	}
4651	>	public boolean equals(Object o) {
4652	>	Set<?> c;
4653	>	return ((o instanceof Set) &&
4654	>	((c = (Set<?>)o) == this ||
4655	>	(containsAll(c) && c.containsAll(this))));
4656	>	}
4657	>
4658	>	public Stream<K> stream() {
4659	>	return Streams.stream(() -> new KeyIterator<K,V>(map), 0);
4660	>	}
4661	>	public Stream<K> parallelStream() {
4662	>	return Streams.parallelStream(() -> new KeyIterator<K,V>(map, null),
4663	>	0);
4664	>	}
4665	>	}
4666	>
4667	>	/**
4668	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4669	>	* values, in which additions are disabled. This class cannot be
4670	>	* directly instantiated. See {@link #values},
4671	>	*
4672	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
4673	>	* that will never throw {@link ConcurrentModificationException},
4674	>	* and guarantees to traverse elements as they existed upon
4675	>	* construction of the iterator, and may (but is not guaranteed to)
4676	>	* reflect any modifications subsequent to construction.
4677	>	*/
4678	>	public static final class ValuesView<K,V> extends CHMView<K,V>
4679	>	implements Collection<V> {
4680	>	ValuesView(ConcurrentHashMap<K, V> map)   { super(map); }
4681	>	public final boolean contains(Object o) { return map.containsValue(o); }
4682	>	public final boolean remove(Object o) {
4683	>	if (o != null) {
4684	>	Iterator<V> it = new ValueIterator<K,V>(map);
4685	>	while (it.hasNext()) {
4686	>	if (o.equals(it.next())) {
4687	>	it.remove();
4688	>	return true;
4689		}
4690		}
1420	–	} finally {
1421	–	seg.unlock();
4691		}
4692	+	return false;
4693		}
4694	<	s.writeObject(null);
4695	<	s.writeObject(null);
4694	>
4695	>	/**
4696	>	* Returns a "weakly consistent" iterator that will never
4697	>	* throw {@link ConcurrentModificationException}, and
4698	>	* guarantees to traverse elements as they existed upon
4699	>	* construction of the iterator, and may (but is not
4700	>	* guaranteed to) reflect any modifications subsequent to
4701	>	* construction.
4702	>	*
4703	>	* @return an iterator over the values of this map
4704	>	*/
4705	>	public final Iterator<V> iterator() {
4706	>	return new ValueIterator<K,V>(map);
4707	>	}
4708	>	public final boolean add(V e) {
4709	>	throw new UnsupportedOperationException();
4710	>	}
4711	>	public final boolean addAll(Collection<? extends V> c) {
4712	>	throw new UnsupportedOperationException();
4713	>	}
4714	>
4715	>	public Stream<V> stream() {
4716	>	return Streams.stream(() -> new ValueIterator<K,V>(map), 0);
4717	>	}
4718	>
4719	>	public Stream<V> parallelStream() {
4720	>	return Streams.parallelStream(() -> new ValueIterator<K,V>(map, null),
4721	>	0);
4722	>	}
4723	>
4724		}
4725
4726		/**
4727	<	* Reconstitutes the <tt>ConcurrentHashMap</tt> instance from a
4728	<	* stream (i.e., deserializes it).
4729	<	* @param s the stream
4727	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4728	>	* entries.  This class cannot be directly instantiated. See
4729	>	* {@link #entrySet}.
4730		*/
4731	<	@SuppressWarnings("unchecked")
4732	<	private void readObject(java.io.ObjectInputStream s)
4733	<	throws java.io.IOException, ClassNotFoundException {
4734	<	s.defaultReadObject();
4731	>	public static final class EntrySetView<K,V> extends CHMView<K,V>
4732	>	implements Set<Map.Entry<K,V>> {
4733	>	EntrySetView(ConcurrentHashMap<K, V> map) { super(map); }
4734	>	public final boolean contains(Object o) {
4735	>	Object k, v, r; Map.Entry<?,?> e;
4736	>	return ((o instanceof Map.Entry) &&
4737	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4738	>	(r = map.get(k)) != null &&
4739	>	(v = e.getValue()) != null &&
4740	>	(v == r || v.equals(r)));
4741	>	}
4742	>	public final boolean remove(Object o) {
4743	>	Object k, v; Map.Entry<?,?> e;
4744	>	return ((o instanceof Map.Entry) &&
4745	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4746	>	(v = e.getValue()) != null &&
4747	>	map.remove(k, v));
4748	>	}
4749
4750	<	// Re-initialize segments to be minimally sized, and let grow.
4751	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
4752	<	final Segment<K,V>[] segments = this.segments;
4753	<	for (int k = 0; k < segments.length; ++k) {
4754	<	Segment<K,V> seg = segments[k];
4755	<	if (seg != null) {
4756	<	seg.threshold = (int)(cap * seg.loadFactor);
4757	<	seg.table = (HashEntry<K,V>[]) new HashEntry<?,?>[cap];
4750	>	/**
4751	>	* Returns a "weakly consistent" iterator that will never
4752	>	* throw {@link ConcurrentModificationException}, and
4753	>	* guarantees to traverse elements as they existed upon
4754	>	* construction of the iterator, and may (but is not
4755	>	* guaranteed to) reflect any modifications subsequent to
4756	>	* construction.
4757	>	*
4758	>	* @return an iterator over the entries of this map
4759	>	*/
4760	>	public final Iterator<Map.Entry<K,V>> iterator() {
4761	>	return new EntryIterator<K,V>(map);
4762	>	}
4763	>
4764	>	public final boolean add(Entry<K,V> e) {
4765	>	K key = e.getKey();
4766	>	V value = e.getValue();
4767	>	if (key == null || value == null)
4768	>	throw new NullPointerException();
4769	>	return map.internalPut(key, value, false) == null;
4770	>	}
4771	>	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
4772	>	boolean added = false;
4773	>	for (Entry<K,V> e : c) {
4774	>	if (add(e))
4775	>	added = true;
4776		}
4777	+	return added;
4778	+	}
4779	+	public boolean equals(Object o) {
4780	+	Set<?> c;
4781	+	return ((o instanceof Set) &&
4782	+	((c = (Set<?>)o) == this ||
4783	+	(containsAll(c) && c.containsAll(this))));
4784		}
4785
4786	<	// Read the keys and values, and put the mappings in the table
4787	<	for (;;) {
4788	<	K key = (K) s.readObject();
4789	<	V value = (V) s.readObject();
4790	<	if (key == null)
4791	<	break;
4792	<	put(key, value);
4786	>	public Stream<Map.Entry<K,V>> stream() {
4787	>	return Streams.stream(() -> new EntryIterator<K,V>(map), 0);
4788	>	}
4789	>
4790	>	public Stream<Map.Entry<K,V>> parallelStream() {
4791	>	return Streams.parallelStream(() -> new EntryIterator<K,V>(map, null),
4792	>	0);
4793	>	}
4794	>	}
4795	>
4796	>	// ---------------------------------------------------------------------
4797	>
4798	>	/**
4799	>	* Predefined tasks for performing bulk parallel operations on
4800	>	* ConcurrentHashMaps. These tasks follow the forms and rules used
4801	>	* for bulk operations. Each method has the same name, but returns
4802	>	* a task rather than invoking it. These methods may be useful in
4803	>	* custom applications such as submitting a task without waiting
4804	>	* for completion, using a custom pool, or combining with other
4805	>	* tasks.
4806	>	*/
4807	>	public static class ForkJoinTasks {
4808	>	private ForkJoinTasks() {}
4809	>
4810	>	/**
4811	>	* Returns a task that when invoked, performs the given
4812	>	* action for each (key, value)
4813	>	*
4814	>	* @param map the map
4815	>	* @param action the action
4816	>	* @return the task
4817	>	*/
4818	>	public static <K,V> ForkJoinTask<Void> forEach
4819	>	(ConcurrentHashMap<K,V> map,
4820	>	BiBlock<? super K, ? super V> action) {
4821	>	if (action == null) throw new NullPointerException();
4822	>	return new ForEachMappingTask<K,V>(map, null, -1, action);
4823	>	}
4824	>
4825	>	/**
4826	>	* Returns a task that when invoked, performs the given
4827	>	* action for each non-null transformation of each (key, value)
4828	>	*
4829	>	* @param map the map
4830	>	* @param transformer a function returning the transformation
4831	>	* for an element, or null if there is no transformation (in
4832	>	* which case the action is not applied)
4833	>	* @param action the action
4834	>	* @return the task
4835	>	*/
4836	>	public static <K,V,U> ForkJoinTask<Void> forEach
4837	>	(ConcurrentHashMap<K,V> map,
4838	>	BiFunction<? super K, ? super V, ? extends U> transformer,
4839	>	Block<? super U> action) {
4840	>	if (transformer == null || action == null)
4841	>	throw new NullPointerException();
4842	>	return new ForEachTransformedMappingTask<K,V,U>
4843	>	(map, null, -1, transformer, action);
4844	>	}
4845	>
4846	>	/**
4847	>	* Returns a task that when invoked, returns a non-null result
4848	>	* from applying the given search function on each (key,
4849	>	* value), or null if none. Upon success, further element
4850	>	* processing is suppressed and the results of any other
4851	>	* parallel invocations of the search function are ignored.
4852	>	*
4853	>	* @param map the map
4854	>	* @param searchFunction a function returning a non-null
4855	>	* result on success, else null
4856	>	* @return the task
4857	>	*/
4858	>	public static <K,V,U> ForkJoinTask<U> search
4859	>	(ConcurrentHashMap<K,V> map,
4860	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
4861	>	if (searchFunction == null) throw new NullPointerException();
4862	>	return new SearchMappingsTask<K,V,U>
4863	>	(map, null, -1, searchFunction,
4864	>	new AtomicReference<U>());
4865	>	}
4866	>
4867	>	/**
4868	>	* Returns a task that when invoked, returns the result of
4869	>	* accumulating the given transformation of all (key, value) pairs
4870	>	* using the given reducer to combine values, or null if none.
4871	>	*
4872	>	* @param map the map
4873	>	* @param transformer a function returning the transformation
4874	>	* for an element, or null if there is no transformation (in
4875	>	* which case it is not combined).
4876	>	* @param reducer a commutative associative combining function
4877	>	* @return the task
4878	>	*/
4879	>	public static <K,V,U> ForkJoinTask<U> reduce
4880	>	(ConcurrentHashMap<K,V> map,
4881	>	BiFunction<? super K, ? super V, ? extends U> transformer,
4882	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4883	>	if (transformer == null || reducer == null)
4884	>	throw new NullPointerException();
4885	>	return new MapReduceMappingsTask<K,V,U>
4886	>	(map, null, -1, null, transformer, reducer);
4887	>	}
4888	>
4889	>	/**
4890	>	* Returns a task that when invoked, returns the result of
4891	>	* accumulating the given transformation of all (key, value) pairs
4892	>	* using the given reducer to combine values, and the given
4893	>	* basis as an identity value.
4894	>	*
4895	>	* @param map the map
4896	>	* @param transformer a function returning the transformation
4897	>	* for an element
4898	>	* @param basis the identity (initial default value) for the reduction
4899	>	* @param reducer a commutative associative combining function
4900	>	* @return the task
4901	>	*/
4902	>	public static <K,V> ForkJoinTask<Double> reduceToDouble
4903	>	(ConcurrentHashMap<K,V> map,
4904	>	DoubleBiFunction<? super K, ? super V> transformer,
4905	>	double basis,
4906	>	DoubleBinaryOperator reducer) {
4907	>	if (transformer == null || reducer == null)
4908	>	throw new NullPointerException();
4909	>	return new MapReduceMappingsToDoubleTask<K,V>
4910	>	(map, null, -1, null, transformer, basis, reducer);
4911	>	}
4912	>
4913	>	/**
4914	>	* Returns a task that when invoked, returns the result of
4915	>	* accumulating the given transformation of all (key, value) pairs
4916	>	* using the given reducer to combine values, and the given
4917	>	* basis as an identity value.
4918	>	*
4919	>	* @param map the map
4920	>	* @param transformer a function returning the transformation
4921	>	* for an element
4922	>	* @param basis the identity (initial default value) for the reduction
4923	>	* @param reducer a commutative associative combining function
4924	>	* @return the task
4925	>	*/
4926	>	public static <K,V> ForkJoinTask<Long> reduceToLong
4927	>	(ConcurrentHashMap<K,V> map,
4928	>	LongBiFunction<? super K, ? super V> transformer,
4929	>	long basis,
4930	>	LongBinaryOperator reducer) {
4931	>	if (transformer == null || reducer == null)
4932	>	throw new NullPointerException();
4933	>	return new MapReduceMappingsToLongTask<K,V>
4934	>	(map, null, -1, null, transformer, basis, reducer);
4935	>	}
4936	>
4937	>	/**
4938	>	* Returns a task that when invoked, returns the result of
4939	>	* accumulating the given transformation of all (key, value) pairs
4940	>	* using the given reducer to combine values, and the given
4941	>	* basis as an identity value.
4942	>	*
4943	>	* @param transformer a function returning the transformation
4944	>	* for an element
4945	>	* @param basis the identity (initial default value) for the reduction
4946	>	* @param reducer a commutative associative combining function
4947	>	* @return the task
4948	>	*/
4949	>	public static <K,V> ForkJoinTask<Integer> reduceToInt
4950	>	(ConcurrentHashMap<K,V> map,
4951	>	IntBiFunction<? super K, ? super V> transformer,
4952	>	int basis,
4953	>	IntBinaryOperator reducer) {
4954	>	if (transformer == null || reducer == null)
4955	>	throw new NullPointerException();
4956	>	return new MapReduceMappingsToIntTask<K,V>
4957	>	(map, null, -1, null, transformer, basis, reducer);
4958	>	}
4959	>
4960	>	/**
4961	>	* Returns a task that when invoked, performs the given action
4962	>	* for each key.
4963	>	*
4964	>	* @param map the map
4965	>	* @param action the action
4966	>	* @return the task
4967	>	*/
4968	>	public static <K,V> ForkJoinTask<Void> forEachKey
4969	>	(ConcurrentHashMap<K,V> map,
4970	>	Block<? super K> action) {
4971	>	if (action == null) throw new NullPointerException();
4972	>	return new ForEachKeyTask<K,V>(map, null, -1, action);
4973	>	}
4974	>
4975	>	/**
4976	>	* Returns a task that when invoked, performs the given action
4977	>	* for each non-null transformation of each key.
4978	>	*
4979	>	* @param map the map
4980	>	* @param transformer a function returning the transformation
4981	>	* for an element, or null if there is no transformation (in
4982	>	* which case the action is not applied)
4983	>	* @param action the action
4984	>	* @return the task
4985	>	*/
4986	>	public static <K,V,U> ForkJoinTask<Void> forEachKey
4987	>	(ConcurrentHashMap<K,V> map,
4988	>	Function<? super K, ? extends U> transformer,
4989	>	Block<? super U> action) {
4990	>	if (transformer == null || action == null)
4991	>	throw new NullPointerException();
4992	>	return new ForEachTransformedKeyTask<K,V,U>
4993	>	(map, null, -1, transformer, action);
4994	>	}
4995	>
4996	>	/**
4997	>	* Returns a task that when invoked, returns a non-null result
4998	>	* from applying the given search function on each key, or
4999	>	* null if none.  Upon success, further element processing is
5000	>	* suppressed and the results of any other parallel
5001	>	* invocations of the search function are ignored.
5002	>	*
5003	>	* @param map the map
5004	>	* @param searchFunction a function returning a non-null
5005	>	* result on success, else null
5006	>	* @return the task
5007	>	*/
5008	>	public static <K,V,U> ForkJoinTask<U> searchKeys
5009	>	(ConcurrentHashMap<K,V> map,
5010	>	Function<? super K, ? extends U> searchFunction) {
5011	>	if (searchFunction == null) throw new NullPointerException();
5012	>	return new SearchKeysTask<K,V,U>
5013	>	(map, null, -1, searchFunction,
5014	>	new AtomicReference<U>());
5015	>	}
5016	>
5017	>	/**
5018	>	* Returns a task that when invoked, returns the result of
5019	>	* accumulating all keys using the given reducer to combine
5020	>	* values, or null if none.
5021	>	*
5022	>	* @param map the map
5023	>	* @param reducer a commutative associative combining function
5024	>	* @return the task
5025	>	*/
5026	>	public static <K,V> ForkJoinTask<K> reduceKeys
5027	>	(ConcurrentHashMap<K,V> map,
5028	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5029	>	if (reducer == null) throw new NullPointerException();
5030	>	return new ReduceKeysTask<K,V>
5031	>	(map, null, -1, null, reducer);
5032	>	}
5033	>
5034	>	/**
5035	>	* Returns a task that when invoked, returns the result of
5036	>	* accumulating the given transformation of all keys using the given
5037	>	* reducer to combine values, or null if none.
5038	>	*
5039	>	* @param map the map
5040	>	* @param transformer a function returning the transformation
5041	>	* for an element, or null if there is no transformation (in
5042	>	* which case it is not combined).
5043	>	* @param reducer a commutative associative combining function
5044	>	* @return the task
5045	>	*/
5046	>	public static <K,V,U> ForkJoinTask<U> reduceKeys
5047	>	(ConcurrentHashMap<K,V> map,
5048	>	Function<? super K, ? extends U> transformer,
5049	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5050	>	if (transformer == null || reducer == null)
5051	>	throw new NullPointerException();
5052	>	return new MapReduceKeysTask<K,V,U>
5053	>	(map, null, -1, null, transformer, reducer);
5054	>	}
5055	>
5056	>	/**
5057	>	* Returns a task that when invoked, returns the result of
5058	>	* accumulating the given transformation of all keys using the given
5059	>	* reducer to combine values, and the given basis as an
5060	>	* identity value.
5061	>	*
5062	>	* @param map the map
5063	>	* @param transformer a function returning the transformation
5064	>	* for an element
5065	>	* @param basis the identity (initial default value) for the reduction
5066	>	* @param reducer a commutative associative combining function
5067	>	* @return the task
5068	>	*/
5069	>	public static <K,V> ForkJoinTask<Double> reduceKeysToDouble
5070	>	(ConcurrentHashMap<K,V> map,
5071	>	DoubleFunction<? super K> transformer,
5072	>	double basis,
5073	>	DoubleBinaryOperator reducer) {
5074	>	if (transformer == null || reducer == null)
5075	>	throw new NullPointerException();
5076	>	return new MapReduceKeysToDoubleTask<K,V>
5077	>	(map, null, -1, null, transformer, basis, reducer);
5078	>	}
5079	>
5080	>	/**
5081	>	* Returns a task that when invoked, returns the result of
5082	>	* accumulating the given transformation of all keys using the given
5083	>	* reducer to combine values, and the given basis as an
5084	>	* identity value.
5085	>	*
5086	>	* @param map the map
5087	>	* @param transformer a function returning the transformation
5088	>	* for an element
5089	>	* @param basis the identity (initial default value) for the reduction
5090	>	* @param reducer a commutative associative combining function
5091	>	* @return the task
5092	>	*/
5093	>	public static <K,V> ForkJoinTask<Long> reduceKeysToLong
5094	>	(ConcurrentHashMap<K,V> map,
5095	>	LongFunction<? super K> transformer,
5096	>	long basis,
5097	>	LongBinaryOperator reducer) {
5098	>	if (transformer == null || reducer == null)
5099	>	throw new NullPointerException();
5100	>	return new MapReduceKeysToLongTask<K,V>
5101	>	(map, null, -1, null, transformer, basis, reducer);
5102	>	}
5103	>
5104	>	/**
5105	>	* Returns a task that when invoked, returns the result of
5106	>	* accumulating the given transformation of all keys using the given
5107	>	* reducer to combine values, and the given basis as an
5108	>	* identity value.
5109	>	*
5110	>	* @param map the map
5111	>	* @param transformer a function returning the transformation
5112	>	* for an element
5113	>	* @param basis the identity (initial default value) for the reduction
5114	>	* @param reducer a commutative associative combining function
5115	>	* @return the task
5116	>	*/
5117	>	public static <K,V> ForkJoinTask<Integer> reduceKeysToInt
5118	>	(ConcurrentHashMap<K,V> map,
5119	>	IntFunction<? super K> transformer,
5120	>	int basis,
5121	>	IntBinaryOperator reducer) {
5122	>	if (transformer == null || reducer == null)
5123	>	throw new NullPointerException();
5124	>	return new MapReduceKeysToIntTask<K,V>
5125	>	(map, null, -1, null, transformer, basis, reducer);
5126	>	}
5127	>
5128	>	/**
5129	>	* Returns a task that when invoked, performs the given action
5130	>	* for each value.
5131	>	*
5132	>	* @param map the map
5133	>	* @param action the action
5134	>	*/
5135	>	public static <K,V> ForkJoinTask<Void> forEachValue
5136	>	(ConcurrentHashMap<K,V> map,
5137	>	Block<? super V> action) {
5138	>	if (action == null) throw new NullPointerException();
5139	>	return new ForEachValueTask<K,V>(map, null, -1, action);
5140	>	}
5141	>
5142	>	/**
5143	>	* Returns a task that when invoked, performs the given action
5144	>	* for each non-null transformation of each value.
5145	>	*
5146	>	* @param map the map
5147	>	* @param transformer a function returning the transformation
5148	>	* for an element, or null if there is no transformation (in
5149	>	* which case the action is not applied)
5150	>	* @param action the action
5151	>	*/
5152	>	public static <K,V,U> ForkJoinTask<Void> forEachValue
5153	>	(ConcurrentHashMap<K,V> map,
5154	>	Function<? super V, ? extends U> transformer,
5155	>	Block<? super U> action) {
5156	>	if (transformer == null || action == null)
5157	>	throw new NullPointerException();
5158	>	return new ForEachTransformedValueTask<K,V,U>
5159	>	(map, null, -1, transformer, action);
5160	>	}
5161	>
5162	>	/**
5163	>	* Returns a task that when invoked, returns a non-null result
5164	>	* from applying the given search function on each value, or
5165	>	* null if none.  Upon success, further element processing is
5166	>	* suppressed and the results of any other parallel
5167	>	* invocations of the search function are ignored.
5168	>	*
5169	>	* @param map the map
5170	>	* @param searchFunction a function returning a non-null
5171	>	* result on success, else null
5172	>	* @return the task
5173	>	*/
5174	>	public static <K,V,U> ForkJoinTask<U> searchValues
5175	>	(ConcurrentHashMap<K,V> map,
5176	>	Function<? super V, ? extends U> searchFunction) {
5177	>	if (searchFunction == null) throw new NullPointerException();
5178	>	return new SearchValuesTask<K,V,U>
5179	>	(map, null, -1, searchFunction,
5180	>	new AtomicReference<U>());
5181	>	}
5182	>
5183	>	/**
5184	>	* Returns a task that when invoked, returns the result of
5185	>	* accumulating all values using the given reducer to combine
5186	>	* values, or null if none.
5187	>	*
5188	>	* @param map the map
5189	>	* @param reducer a commutative associative combining function
5190	>	* @return the task
5191	>	*/
5192	>	public static <K,V> ForkJoinTask<V> reduceValues
5193	>	(ConcurrentHashMap<K,V> map,
5194	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5195	>	if (reducer == null) throw new NullPointerException();
5196	>	return new ReduceValuesTask<K,V>
5197	>	(map, null, -1, null, reducer);
5198	>	}
5199	>
5200	>	/**
5201	>	* Returns a task that when invoked, returns the result of
5202	>	* accumulating the given transformation of all values using the
5203	>	* given reducer to combine values, or null if none.
5204	>	*
5205	>	* @param map the map
5206	>	* @param transformer a function returning the transformation
5207	>	* for an element, or null if there is no transformation (in
5208	>	* which case it is not combined).
5209	>	* @param reducer a commutative associative combining function
5210	>	* @return the task
5211	>	*/
5212	>	public static <K,V,U> ForkJoinTask<U> reduceValues
5213	>	(ConcurrentHashMap<K,V> map,
5214	>	Function<? super V, ? extends U> transformer,
5215	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5216	>	if (transformer == null || reducer == null)
5217	>	throw new NullPointerException();
5218	>	return new MapReduceValuesTask<K,V,U>
5219	>	(map, null, -1, null, transformer, reducer);
5220	>	}
5221	>
5222	>	/**
5223	>	* Returns a task that when invoked, returns the result of
5224	>	* accumulating the given transformation of all values using the
5225	>	* given reducer to combine values, and the given basis as an
5226	>	* identity value.
5227	>	*
5228	>	* @param map the map
5229	>	* @param transformer a function returning the transformation
5230	>	* for an element
5231	>	* @param basis the identity (initial default value) for the reduction
5232	>	* @param reducer a commutative associative combining function
5233	>	* @return the task
5234	>	*/
5235	>	public static <K,V> ForkJoinTask<Double> reduceValuesToDouble
5236	>	(ConcurrentHashMap<K,V> map,
5237	>	DoubleFunction<? super V> transformer,
5238	>	double basis,
5239	>	DoubleBinaryOperator reducer) {
5240	>	if (transformer == null || reducer == null)
5241	>	throw new NullPointerException();
5242	>	return new MapReduceValuesToDoubleTask<K,V>
5243	>	(map, null, -1, null, transformer, basis, reducer);
5244	>	}
5245	>
5246	>	/**
5247	>	* Returns a task that when invoked, returns the result of
5248	>	* accumulating the given transformation of all values using the
5249	>	* given reducer to combine values, and the given basis as an
5250	>	* identity value.
5251	>	*
5252	>	* @param map the map
5253	>	* @param transformer a function returning the transformation
5254	>	* for an element
5255	>	* @param basis the identity (initial default value) for the reduction
5256	>	* @param reducer a commutative associative combining function
5257	>	* @return the task
5258	>	*/
5259	>	public static <K,V> ForkJoinTask<Long> reduceValuesToLong
5260	>	(ConcurrentHashMap<K,V> map,
5261	>	LongFunction<? super V> transformer,
5262	>	long basis,
5263	>	LongBinaryOperator reducer) {
5264	>	if (transformer == null || reducer == null)
5265	>	throw new NullPointerException();
5266	>	return new MapReduceValuesToLongTask<K,V>
5267	>	(map, null, -1, null, transformer, basis, reducer);
5268	>	}
5269	>
5270	>	/**
5271	>	* Returns a task that when invoked, returns the result of
5272	>	* accumulating the given transformation of all values using the
5273	>	* given reducer to combine values, and the given basis as an
5274	>	* identity value.
5275	>	*
5276	>	* @param map the map
5277	>	* @param transformer a function returning the transformation
5278	>	* for an element
5279	>	* @param basis the identity (initial default value) for the reduction
5280	>	* @param reducer a commutative associative combining function
5281	>	* @return the task
5282	>	*/
5283	>	public static <K,V> ForkJoinTask<Integer> reduceValuesToInt
5284	>	(ConcurrentHashMap<K,V> map,
5285	>	IntFunction<? super V> transformer,
5286	>	int basis,
5287	>	IntBinaryOperator reducer) {
5288	>	if (transformer == null || reducer == null)
5289	>	throw new NullPointerException();
5290	>	return new MapReduceValuesToIntTask<K,V>
5291	>	(map, null, -1, null, transformer, basis, reducer);
5292	>	}
5293	>
5294	>	/**
5295	>	* Returns a task that when invoked, perform the given action
5296	>	* for each entry.
5297	>	*
5298	>	* @param map the map
5299	>	* @param action the action
5300	>	*/
5301	>	public static <K,V> ForkJoinTask<Void> forEachEntry
5302	>	(ConcurrentHashMap<K,V> map,
5303	>	Block<? super Map.Entry<K,V>> action) {
5304	>	if (action == null) throw new NullPointerException();
5305	>	return new ForEachEntryTask<K,V>(map, null, -1, action);
5306	>	}
5307	>
5308	>	/**
5309	>	* Returns a task that when invoked, perform the given action
5310	>	* for each non-null transformation of each entry.
5311	>	*
5312	>	* @param map the map
5313	>	* @param transformer a function returning the transformation
5314	>	* for an element, or null if there is no transformation (in
5315	>	* which case the action is not applied)
5316	>	* @param action the action
5317	>	*/
5318	>	public static <K,V,U> ForkJoinTask<Void> forEachEntry
5319	>	(ConcurrentHashMap<K,V> map,
5320	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5321	>	Block<? super U> action) {
5322	>	if (transformer == null || action == null)
5323	>	throw new NullPointerException();
5324	>	return new ForEachTransformedEntryTask<K,V,U>
5325	>	(map, null, -1, transformer, action);
5326	>	}
5327	>
5328	>	/**
5329	>	* Returns a task that when invoked, returns a non-null result
5330	>	* from applying the given search function on each entry, or
5331	>	* null if none.  Upon success, further element processing is
5332	>	* suppressed and the results of any other parallel
5333	>	* invocations of the search function are ignored.
5334	>	*
5335	>	* @param map the map
5336	>	* @param searchFunction a function returning a non-null
5337	>	* result on success, else null
5338	>	* @return the task
5339	>	*/
5340	>	public static <K,V,U> ForkJoinTask<U> searchEntries
5341	>	(ConcurrentHashMap<K,V> map,
5342	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
5343	>	if (searchFunction == null) throw new NullPointerException();
5344	>	return new SearchEntriesTask<K,V,U>
5345	>	(map, null, -1, searchFunction,
5346	>	new AtomicReference<U>());
5347	>	}
5348	>
5349	>	/**
5350	>	* Returns a task that when invoked, returns the result of
5351	>	* accumulating all entries using the given reducer to combine
5352	>	* values, or null if none.
5353	>	*
5354	>	* @param map the map
5355	>	* @param reducer a commutative associative combining function
5356	>	* @return the task
5357	>	*/
5358	>	public static <K,V> ForkJoinTask<Map.Entry<K,V>> reduceEntries
5359	>	(ConcurrentHashMap<K,V> map,
5360	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5361	>	if (reducer == null) throw new NullPointerException();
5362	>	return new ReduceEntriesTask<K,V>
5363	>	(map, null, -1, null, reducer);
5364	>	}
5365	>
5366	>	/**
5367	>	* Returns a task that when invoked, returns the result of
5368	>	* accumulating the given transformation of all entries using the
5369	>	* given reducer to combine values, or null if none.
5370	>	*
5371	>	* @param map the map
5372	>	* @param transformer a function returning the transformation
5373	>	* for an element, or null if there is no transformation (in
5374	>	* which case it is not combined).
5375	>	* @param reducer a commutative associative combining function
5376	>	* @return the task
5377	>	*/
5378	>	public static <K,V,U> ForkJoinTask<U> reduceEntries
5379	>	(ConcurrentHashMap<K,V> map,
5380	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5381	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5382	>	if (transformer == null || reducer == null)
5383	>	throw new NullPointerException();
5384	>	return new MapReduceEntriesTask<K,V,U>
5385	>	(map, null, -1, null, transformer, reducer);
5386	>	}
5387	>
5388	>	/**
5389	>	* Returns a task that when invoked, returns the result of
5390	>	* accumulating the given transformation of all entries using the
5391	>	* given reducer to combine values, and the given basis as an
5392	>	* identity value.
5393	>	*
5394	>	* @param map the map
5395	>	* @param transformer a function returning the transformation
5396	>	* for an element
5397	>	* @param basis the identity (initial default value) for the reduction
5398	>	* @param reducer a commutative associative combining function
5399	>	* @return the task
5400	>	*/
5401	>	public static <K,V> ForkJoinTask<Double> reduceEntriesToDouble
5402	>	(ConcurrentHashMap<K,V> map,
5403	>	DoubleFunction<Map.Entry<K,V>> transformer,
5404	>	double basis,
5405	>	DoubleBinaryOperator reducer) {
5406	>	if (transformer == null || reducer == null)
5407	>	throw new NullPointerException();
5408	>	return new MapReduceEntriesToDoubleTask<K,V>
5409	>	(map, null, -1, null, transformer, basis, reducer);
5410	>	}
5411	>
5412	>	/**
5413	>	* Returns a task that when invoked, returns the result of
5414	>	* accumulating the given transformation of all entries using the
5415	>	* given reducer to combine values, and the given basis as an
5416	>	* identity value.
5417	>	*
5418	>	* @param map the map
5419	>	* @param transformer a function returning the transformation
5420	>	* for an element
5421	>	* @param basis the identity (initial default value) for the reduction
5422	>	* @param reducer a commutative associative combining function
5423	>	* @return the task
5424	>	*/
5425	>	public static <K,V> ForkJoinTask<Long> reduceEntriesToLong
5426	>	(ConcurrentHashMap<K,V> map,
5427	>	LongFunction<Map.Entry<K,V>> transformer,
5428	>	long basis,
5429	>	LongBinaryOperator reducer) {
5430	>	if (transformer == null || reducer == null)
5431	>	throw new NullPointerException();
5432	>	return new MapReduceEntriesToLongTask<K,V>
5433	>	(map, null, -1, null, transformer, basis, reducer);
5434	>	}
5435	>
5436	>	/**
5437	>	* Returns a task that when invoked, returns the result of
5438	>	* accumulating the given transformation of all entries using the
5439	>	* given reducer to combine values, and the given basis as an
5440	>	* identity value.
5441	>	*
5442	>	* @param map the map
5443	>	* @param transformer a function returning the transformation
5444	>	* for an element
5445	>	* @param basis the identity (initial default value) for the reduction
5446	>	* @param reducer a commutative associative combining function
5447	>	* @return the task
5448	>	*/
5449	>	public static <K,V> ForkJoinTask<Integer> reduceEntriesToInt
5450	>	(ConcurrentHashMap<K,V> map,
5451	>	IntFunction<Map.Entry<K,V>> transformer,
5452	>	int basis,
5453	>	IntBinaryOperator reducer) {
5454	>	if (transformer == null || reducer == null)
5455	>	throw new NullPointerException();
5456	>	return new MapReduceEntriesToIntTask<K,V>
5457	>	(map, null, -1, null, transformer, basis, reducer);
5458	>	}
5459	>	}
5460	>
5461	>	// -------------------------------------------------------
5462	>
5463	>	/*
5464	>	* Task classes. Coded in a regular but ugly format/style to
5465	>	* simplify checks that each variant differs in the right way from
5466	>	* others. The null screenings exist because compilers cannot tell
5467	>	* that we've already null-checked task arguments, so we force
5468	>	* simplest hoisted bypass to help avoid convoluted traps.
5469	>	*/
5470	>
5471	>	@SuppressWarnings("serial") static final class ForEachKeyTask<K,V>
5472	>	extends Traverser<K,V,Void> {
5473	>	final Block<? super K> action;
5474	>	ForEachKeyTask
5475	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5476	>	Block<? super K> action) {
5477	>	super(m, p, b);
5478	>	this.action = action;
5479	>	}
5480	>	@SuppressWarnings("unchecked") public final void compute() {
5481	>	final Block<? super K> action;
5482	>	if ((action = this.action) != null) {
5483	>	for (int b; (b = preSplit()) > 0;)
5484	>	new ForEachKeyTask<K,V>(map, this, b, action).fork();
5485	>	while (advance() != null)
5486	>	action.accept((K)nextKey);
5487	>	propagateCompletion();
5488	>	}
5489	>	}
5490	>	}
5491	>
5492	>	@SuppressWarnings("serial") static final class ForEachValueTask<K,V>
5493	>	extends Traverser<K,V,Void> {
5494	>	final Block<? super V> action;
5495	>	ForEachValueTask
5496	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5497	>	Block<? super V> action) {
5498	>	super(m, p, b);
5499	>	this.action = action;
5500	>	}
5501	>	@SuppressWarnings("unchecked") public final void compute() {
5502	>	final Block<? super V> action;
5503	>	if ((action = this.action) != null) {
5504	>	for (int b; (b = preSplit()) > 0;)
5505	>	new ForEachValueTask<K,V>(map, this, b, action).fork();
5506	>	V v;
5507	>	while ((v = advance()) != null)
5508	>	action.accept(v);
5509	>	propagateCompletion();
5510	>	}
5511	>	}
5512	>	}
5513	>
5514	>	@SuppressWarnings("serial") static final class ForEachEntryTask<K,V>
5515	>	extends Traverser<K,V,Void> {
5516	>	final Block<? super Entry<K,V>> action;
5517	>	ForEachEntryTask
5518	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5519	>	Block<? super Entry<K,V>> action) {
5520	>	super(m, p, b);
5521	>	this.action = action;
5522	>	}
5523	>	@SuppressWarnings("unchecked") public final void compute() {
5524	>	final Block<? super Entry<K,V>> action;
5525	>	if ((action = this.action) != null) {
5526	>	for (int b; (b = preSplit()) > 0;)
5527	>	new ForEachEntryTask<K,V>(map, this, b, action).fork();
5528	>	V v;
5529	>	while ((v = advance()) != null)
5530	>	action.accept(entryFor((K)nextKey, v));
5531	>	propagateCompletion();
5532	>	}
5533	>	}
5534	>	}
5535	>
5536	>	@SuppressWarnings("serial") static final class ForEachMappingTask<K,V>
5537	>	extends Traverser<K,V,Void> {
5538	>	final BiBlock<? super K, ? super V> action;
5539	>	ForEachMappingTask
5540	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5541	>	BiBlock<? super K,? super V> action) {
5542	>	super(m, p, b);
5543	>	this.action = action;
5544	>	}
5545	>	@SuppressWarnings("unchecked") public final void compute() {
5546	>	final BiBlock<? super K, ? super V> action;
5547	>	if ((action = this.action) != null) {
5548	>	for (int b; (b = preSplit()) > 0;)
5549	>	new ForEachMappingTask<K,V>(map, this, b, action).fork();
5550	>	V v;
5551	>	while ((v = advance()) != null)
5552	>	action.accept((K)nextKey, v);
5553	>	propagateCompletion();
5554	>	}
5555	>	}
5556	>	}
5557	>
5558	>	@SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U>
5559	>	extends Traverser<K,V,Void> {
5560	>	final Function<? super K, ? extends U> transformer;
5561	>	final Block<? super U> action;
5562	>	ForEachTransformedKeyTask
5563	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5564	>	Function<? super K, ? extends U> transformer, Block<? super U> action) {
5565	>	super(m, p, b);
5566	>	this.transformer = transformer; this.action = action;
5567	>	}
5568	>	@SuppressWarnings("unchecked") public final void compute() {
5569	>	final Function<? super K, ? extends U> transformer;
5570	>	final Block<? super U> action;
5571	>	if ((transformer = this.transformer) != null &&
5572	>	(action = this.action) != null) {
5573	>	for (int b; (b = preSplit()) > 0;)
5574	>	new ForEachTransformedKeyTask<K,V,U>
5575	>	(map, this, b, transformer, action).fork();
5576	>	U u;
5577	>	while (advance() != null) {
5578	>	if ((u = transformer.apply((K)nextKey)) != null)
5579	>	action.accept(u);
5580	>	}
5581	>	propagateCompletion();
5582	>	}
5583	>	}
5584	>	}
5585	>
5586	>	@SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U>
5587	>	extends Traverser<K,V,Void> {
5588	>	final Function<? super V, ? extends U> transformer;
5589	>	final Block<? super U> action;
5590	>	ForEachTransformedValueTask
5591	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5592	>	Function<? super V, ? extends U> transformer, Block<? super U> action) {
5593	>	super(m, p, b);
5594	>	this.transformer = transformer; this.action = action;
5595	>	}
5596	>	@SuppressWarnings("unchecked") public final void compute() {
5597	>	final Function<? super V, ? extends U> transformer;
5598	>	final Block<? super U> action;
5599	>	if ((transformer = this.transformer) != null &&
5600	>	(action = this.action) != null) {
5601	>	for (int b; (b = preSplit()) > 0;)
5602	>	new ForEachTransformedValueTask<K,V,U>
5603	>	(map, this, b, transformer, action).fork();
5604	>	V v; U u;
5605	>	while ((v = advance()) != null) {
5606	>	if ((u = transformer.apply(v)) != null)
5607	>	action.accept(u);
5608	>	}
5609	>	propagateCompletion();
5610	>	}
5611	>	}
5612	>	}
5613	>
5614	>	@SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U>
5615	>	extends Traverser<K,V,Void> {
5616	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5617	>	final Block<? super U> action;
5618	>	ForEachTransformedEntryTask
5619	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5620	>	Function<Map.Entry<K,V>, ? extends U> transformer, Block<? super U> action) {
5621	>	super(m, p, b);
5622	>	this.transformer = transformer; this.action = action;
5623	>	}
5624	>	@SuppressWarnings("unchecked") public final void compute() {
5625	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5626	>	final Block<? super U> action;
5627	>	if ((transformer = this.transformer) != null &&
5628	>	(action = this.action) != null) {
5629	>	for (int b; (b = preSplit()) > 0;)
5630	>	new ForEachTransformedEntryTask<K,V,U>
5631	>	(map, this, b, transformer, action).fork();
5632	>	V v; U u;
5633	>	while ((v = advance()) != null) {
5634	>	if ((u = transformer.apply(entryFor((K)nextKey,
5635	>	v))) != null)
5636	>	action.accept(u);
5637	>	}
5638	>	propagateCompletion();
5639	>	}
5640	>	}
5641	>	}
5642	>
5643	>	@SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U>
5644	>	extends Traverser<K,V,Void> {
5645	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5646	>	final Block<? super U> action;
5647	>	ForEachTransformedMappingTask
5648	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5649	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5650	>	Block<? super U> action) {
5651	>	super(m, p, b);
5652	>	this.transformer = transformer; this.action = action;
5653	>	}
5654	>	@SuppressWarnings("unchecked") public final void compute() {
5655	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5656	>	final Block<? super U> action;
5657	>	if ((transformer = this.transformer) != null &&
5658	>	(action = this.action) != null) {
5659	>	for (int b; (b = preSplit()) > 0;)
5660	>	new ForEachTransformedMappingTask<K,V,U>
5661	>	(map, this, b, transformer, action).fork();
5662	>	V v; U u;
5663	>	while ((v = advance()) != null) {
5664	>	if ((u = transformer.apply((K)nextKey, v)) != null)
5665	>	action.accept(u);
5666	>	}
5667	>	propagateCompletion();
5668	>	}
5669	>	}
5670	>	}
5671	>
5672	>	@SuppressWarnings("serial") static final class SearchKeysTask<K,V,U>
5673	>	extends Traverser<K,V,U> {
5674	>	final Function<? super K, ? extends U> searchFunction;
5675	>	final AtomicReference<U> result;
5676	>	SearchKeysTask
5677	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5678	>	Function<? super K, ? extends U> searchFunction,
5679	>	AtomicReference<U> result) {
5680	>	super(m, p, b);
5681	>	this.searchFunction = searchFunction; this.result = result;
5682	>	}
5683	>	public final U getRawResult() { return result.get(); }
5684	>	@SuppressWarnings("unchecked") public final void compute() {
5685	>	final Function<? super K, ? extends U> searchFunction;
5686	>	final AtomicReference<U> result;
5687	>	if ((searchFunction = this.searchFunction) != null &&
5688	>	(result = this.result) != null) {
5689	>	for (int b;;) {
5690	>	if (result.get() != null)
5691	>	return;
5692	>	if ((b = preSplit()) <= 0)
5693	>	break;
5694	>	new SearchKeysTask<K,V,U>
5695	>	(map, this, b, searchFunction, result).fork();
5696	>	}
5697	>	while (result.get() == null) {
5698	>	U u;
5699	>	if (advance() == null) {
5700	>	propagateCompletion();
5701	>	break;
5702	>	}
5703	>	if ((u = searchFunction.apply((K)nextKey)) != null) {
5704	>	if (result.compareAndSet(null, u))
5705	>	quietlyCompleteRoot();
5706	>	break;
5707	>	}
5708	>	}
5709	>	}
5710	>	}
5711	>	}
5712	>
5713	>	@SuppressWarnings("serial") static final class SearchValuesTask<K,V,U>
5714	>	extends Traverser<K,V,U> {
5715	>	final Function<? super V, ? extends U> searchFunction;
5716	>	final AtomicReference<U> result;
5717	>	SearchValuesTask
5718	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5719	>	Function<? super V, ? extends U> searchFunction,
5720	>	AtomicReference<U> result) {
5721	>	super(m, p, b);
5722	>	this.searchFunction = searchFunction; this.result = result;
5723	>	}
5724	>	public final U getRawResult() { return result.get(); }
5725	>	@SuppressWarnings("unchecked") public final void compute() {
5726	>	final Function<? super V, ? extends U> searchFunction;
5727	>	final AtomicReference<U> result;
5728	>	if ((searchFunction = this.searchFunction) != null &&
5729	>	(result = this.result) != null) {
5730	>	for (int b;;) {
5731	>	if (result.get() != null)
5732	>	return;
5733	>	if ((b = preSplit()) <= 0)
5734	>	break;
5735	>	new SearchValuesTask<K,V,U>
5736	>	(map, this, b, searchFunction, result).fork();
5737	>	}
5738	>	while (result.get() == null) {
5739	>	V v; U u;
5740	>	if ((v = advance()) == null) {
5741	>	propagateCompletion();
5742	>	break;
5743	>	}
5744	>	if ((u = searchFunction.apply(v)) != null) {
5745	>	if (result.compareAndSet(null, u))
5746	>	quietlyCompleteRoot();
5747	>	break;
5748	>	}
5749	>	}
5750	>	}
5751	>	}
5752	>	}
5753	>
5754	>	@SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U>
5755	>	extends Traverser<K,V,U> {
5756	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5757	>	final AtomicReference<U> result;
5758	>	SearchEntriesTask
5759	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5760	>	Function<Entry<K,V>, ? extends U> searchFunction,
5761	>	AtomicReference<U> result) {
5762	>	super(m, p, b);
5763	>	this.searchFunction = searchFunction; this.result = result;
5764	>	}
5765	>	public final U getRawResult() { return result.get(); }
5766	>	@SuppressWarnings("unchecked") public final void compute() {
5767	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5768	>	final AtomicReference<U> result;
5769	>	if ((searchFunction = this.searchFunction) != null &&
5770	>	(result = this.result) != null) {
5771	>	for (int b;;) {
5772	>	if (result.get() != null)
5773	>	return;
5774	>	if ((b = preSplit()) <= 0)
5775	>	break;
5776	>	new SearchEntriesTask<K,V,U>
5777	>	(map, this, b, searchFunction, result).fork();
5778	>	}
5779	>	while (result.get() == null) {
5780	>	V v; U u;
5781	>	if ((v = advance()) == null) {
5782	>	propagateCompletion();
5783	>	break;
5784	>	}
5785	>	if ((u = searchFunction.apply(entryFor((K)nextKey,
5786	>	v))) != null) {
5787	>	if (result.compareAndSet(null, u))
5788	>	quietlyCompleteRoot();
5789	>	return;
5790	>	}
5791	>	}
5792	>	}
5793	>	}
5794	>	}
5795	>
5796	>	@SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U>
5797	>	extends Traverser<K,V,U> {
5798	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5799	>	final AtomicReference<U> result;
5800	>	SearchMappingsTask
5801	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5802	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5803	>	AtomicReference<U> result) {
5804	>	super(m, p, b);
5805	>	this.searchFunction = searchFunction; this.result = result;
5806	>	}
5807	>	public final U getRawResult() { return result.get(); }
5808	>	@SuppressWarnings("unchecked") public final void compute() {
5809	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5810	>	final AtomicReference<U> result;
5811	>	if ((searchFunction = this.searchFunction) != null &&
5812	>	(result = this.result) != null) {
5813	>	for (int b;;) {
5814	>	if (result.get() != null)
5815	>	return;
5816	>	if ((b = preSplit()) <= 0)
5817	>	break;
5818	>	new SearchMappingsTask<K,V,U>
5819	>	(map, this, b, searchFunction, result).fork();
5820	>	}
5821	>	while (result.get() == null) {
5822	>	V v; U u;
5823	>	if ((v = advance()) == null) {
5824	>	propagateCompletion();
5825	>	break;
5826	>	}
5827	>	if ((u = searchFunction.apply((K)nextKey, v)) != null) {
5828	>	if (result.compareAndSet(null, u))
5829	>	quietlyCompleteRoot();
5830	>	break;
5831	>	}
5832	>	}
5833	>	}
5834	>	}
5835	>	}
5836	>
5837	>	@SuppressWarnings("serial") static final class ReduceKeysTask<K,V>
5838	>	extends Traverser<K,V,K> {
5839	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5840	>	K result;
5841	>	ReduceKeysTask<K,V> rights, nextRight;
5842	>	ReduceKeysTask
5843	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5844	>	ReduceKeysTask<K,V> nextRight,
5845	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5846	>	super(m, p, b); this.nextRight = nextRight;
5847	>	this.reducer = reducer;
5848	>	}
5849	>	public final K getRawResult() { return result; }
5850	>	@SuppressWarnings("unchecked") public final void compute() {
5851	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5852	>	if ((reducer = this.reducer) != null) {
5853	>	for (int b; (b = preSplit()) > 0;)
5854	>	(rights = new ReduceKeysTask<K,V>
5855	>	(map, this, b, rights, reducer)).fork();
5856	>	K r = null;
5857	>	while (advance() != null) {
5858	>	K u = (K)nextKey;
5859	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5860	>	}
5861	>	result = r;
5862	>	CountedCompleter<?> c;
5863	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5864	>	ReduceKeysTask<K,V>
5865	>	t = (ReduceKeysTask<K,V>)c,
5866	>	s = t.rights;
5867	>	while (s != null) {
5868	>	K tr, sr;
5869	>	if ((sr = s.result) != null)
5870	>	t.result = (((tr = t.result) == null) ? sr :
5871	>	reducer.apply(tr, sr));
5872	>	s = t.rights = s.nextRight;
5873	>	}
5874	>	}
5875	>	}
5876	>	}
5877	>	}
5878	>
5879	>	@SuppressWarnings("serial") static final class ReduceValuesTask<K,V>
5880	>	extends Traverser<K,V,V> {
5881	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5882	>	V result;
5883	>	ReduceValuesTask<K,V> rights, nextRight;
5884	>	ReduceValuesTask
5885	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5886	>	ReduceValuesTask<K,V> nextRight,
5887	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5888	>	super(m, p, b); this.nextRight = nextRight;
5889	>	this.reducer = reducer;
5890	>	}
5891	>	public final V getRawResult() { return result; }
5892	>	@SuppressWarnings("unchecked") public final void compute() {
5893	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5894	>	if ((reducer = this.reducer) != null) {
5895	>	for (int b; (b = preSplit()) > 0;)
5896	>	(rights = new ReduceValuesTask<K,V>
5897	>	(map, this, b, rights, reducer)).fork();
5898	>	V r = null, v;
5899	>	while ((v = advance()) != null)
5900	>	r = (r == null) ? v : reducer.apply(r, v);
5901	>	result = r;
5902	>	CountedCompleter<?> c;
5903	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5904	>	ReduceValuesTask<K,V>
5905	>	t = (ReduceValuesTask<K,V>)c,
5906	>	s = t.rights;
5907	>	while (s != null) {
5908	>	V tr, sr;
5909	>	if ((sr = s.result) != null)
5910	>	t.result = (((tr = t.result) == null) ? sr :
5911	>	reducer.apply(tr, sr));
5912	>	s = t.rights = s.nextRight;
5913	>	}
5914	>	}
5915	>	}
5916	>	}
5917	>	}
5918	>
5919	>	@SuppressWarnings("serial") static final class ReduceEntriesTask<K,V>
5920	>	extends Traverser<K,V,Map.Entry<K,V>> {
5921	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5922	>	Map.Entry<K,V> result;
5923	>	ReduceEntriesTask<K,V> rights, nextRight;
5924	>	ReduceEntriesTask
5925	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5926	>	ReduceEntriesTask<K,V> nextRight,
5927	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5928	>	super(m, p, b); this.nextRight = nextRight;
5929	>	this.reducer = reducer;
5930	>	}
5931	>	public final Map.Entry<K,V> getRawResult() { return result; }
5932	>	@SuppressWarnings("unchecked") public final void compute() {
5933	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5934	>	if ((reducer = this.reducer) != null) {
5935	>	for (int b; (b = preSplit()) > 0;)
5936	>	(rights = new ReduceEntriesTask<K,V>
5937	>	(map, this, b, rights, reducer)).fork();
5938	>	Map.Entry<K,V> r = null;
5939	>	V v;
5940	>	while ((v = advance()) != null) {
5941	>	Map.Entry<K,V> u = entryFor((K)nextKey, v);
5942	>	r = (r == null) ? u : reducer.apply(r, u);
5943	>	}
5944	>	result = r;
5945	>	CountedCompleter<?> c;
5946	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5947	>	ReduceEntriesTask<K,V>
5948	>	t = (ReduceEntriesTask<K,V>)c,
5949	>	s = t.rights;
5950	>	while (s != null) {
5951	>	Map.Entry<K,V> tr, sr;
5952	>	if ((sr = s.result) != null)
5953	>	t.result = (((tr = t.result) == null) ? sr :
5954	>	reducer.apply(tr, sr));
5955	>	s = t.rights = s.nextRight;
5956	>	}
5957	>	}
5958	>	}
5959	>	}
5960	>	}
5961	>
5962	>	@SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U>
5963	>	extends Traverser<K,V,U> {
5964	>	final Function<? super K, ? extends U> transformer;
5965	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5966	>	U result;
5967	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5968	>	MapReduceKeysTask
5969	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
5970	>	MapReduceKeysTask<K,V,U> nextRight,
5971	>	Function<? super K, ? extends U> transformer,
5972	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5973	>	super(m, p, b); this.nextRight = nextRight;
5974	>	this.transformer = transformer;
5975	>	this.reducer = reducer;
5976	>	}
5977	>	public final U getRawResult() { return result; }
5978	>	@SuppressWarnings("unchecked") public final void compute() {
5979	>	final Function<? super K, ? extends U> transformer;
5980	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5981	>	if ((transformer = this.transformer) != null &&
5982	>	(reducer = this.reducer) != null) {
5983	>	for (int b; (b = preSplit()) > 0;)
5984	>	(rights = new MapReduceKeysTask<K,V,U>
5985	>	(map, this, b, rights, transformer, reducer)).fork();
5986	>	U r = null, u;
5987	>	while (advance() != null) {
5988	>	if ((u = transformer.apply((K)nextKey)) != null)
5989	>	r = (r == null) ? u : reducer.apply(r, u);
5990	>	}
5991	>	result = r;
5992	>	CountedCompleter<?> c;
5993	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5994	>	MapReduceKeysTask<K,V,U>
5995	>	t = (MapReduceKeysTask<K,V,U>)c,
5996	>	s = t.rights;
5997	>	while (s != null) {
5998	>	U tr, sr;
5999	>	if ((sr = s.result) != null)
6000	>	t.result = (((tr = t.result) == null) ? sr :
6001	>	reducer.apply(tr, sr));
6002	>	s = t.rights = s.nextRight;
6003	>	}
6004	>	}
6005	>	}
6006	>	}
6007	>	}
6008	>
6009	>	@SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U>
6010	>	extends Traverser<K,V,U> {
6011	>	final Function<? super V, ? extends U> transformer;
6012	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6013	>	U result;
6014	>	MapReduceValuesTask<K,V,U> rights, nextRight;
6015	>	MapReduceValuesTask
6016	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6017	>	MapReduceValuesTask<K,V,U> nextRight,
6018	>	Function<? super V, ? extends U> transformer,
6019	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6020	>	super(m, p, b); this.nextRight = nextRight;
6021	>	this.transformer = transformer;
6022	>	this.reducer = reducer;
6023	>	}
6024	>	public final U getRawResult() { return result; }
6025	>	@SuppressWarnings("unchecked") public final void compute() {
6026	>	final Function<? super V, ? extends U> transformer;
6027	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6028	>	if ((transformer = this.transformer) != null &&
6029	>	(reducer = this.reducer) != null) {
6030	>	for (int b; (b = preSplit()) > 0;)
6031	>	(rights = new MapReduceValuesTask<K,V,U>
6032	>	(map, this, b, rights, transformer, reducer)).fork();
6033	>	U r = null, u;
6034	>	V v;
6035	>	while ((v = advance()) != null) {
6036	>	if ((u = transformer.apply(v)) != null)
6037	>	r = (r == null) ? u : reducer.apply(r, u);
6038	>	}
6039	>	result = r;
6040	>	CountedCompleter<?> c;
6041	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6042	>	MapReduceValuesTask<K,V,U>
6043	>	t = (MapReduceValuesTask<K,V,U>)c,
6044	>	s = t.rights;
6045	>	while (s != null) {
6046	>	U tr, sr;
6047	>	if ((sr = s.result) != null)
6048	>	t.result = (((tr = t.result) == null) ? sr :
6049	>	reducer.apply(tr, sr));
6050	>	s = t.rights = s.nextRight;
6051	>	}
6052	>	}
6053	>	}
6054	>	}
6055	>	}
6056	>
6057	>	@SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U>
6058	>	extends Traverser<K,V,U> {
6059	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
6060	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6061	>	U result;
6062	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
6063	>	MapReduceEntriesTask
6064	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6065	>	MapReduceEntriesTask<K,V,U> nextRight,
6066	>	Function<Map.Entry<K,V>, ? extends U> transformer,
6067	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6068	>	super(m, p, b); this.nextRight = nextRight;
6069	>	this.transformer = transformer;
6070	>	this.reducer = reducer;
6071	>	}
6072	>	public final U getRawResult() { return result; }
6073	>	@SuppressWarnings("unchecked") public final void compute() {
6074	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
6075	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6076	>	if ((transformer = this.transformer) != null &&
6077	>	(reducer = this.reducer) != null) {
6078	>	for (int b; (b = preSplit()) > 0;)
6079	>	(rights = new MapReduceEntriesTask<K,V,U>
6080	>	(map, this, b, rights, transformer, reducer)).fork();
6081	>	U r = null, u;
6082	>	V v;
6083	>	while ((v = advance()) != null) {
6084	>	if ((u = transformer.apply(entryFor((K)nextKey,
6085	>	v))) != null)
6086	>	r = (r == null) ? u : reducer.apply(r, u);
6087	>	}
6088	>	result = r;
6089	>	CountedCompleter<?> c;
6090	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6091	>	MapReduceEntriesTask<K,V,U>
6092	>	t = (MapReduceEntriesTask<K,V,U>)c,
6093	>	s = t.rights;
6094	>	while (s != null) {
6095	>	U tr, sr;
6096	>	if ((sr = s.result) != null)
6097	>	t.result = (((tr = t.result) == null) ? sr :
6098	>	reducer.apply(tr, sr));
6099	>	s = t.rights = s.nextRight;
6100	>	}
6101	>	}
6102	>	}
6103	>	}
6104	>	}
6105	>
6106	>	@SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U>
6107	>	extends Traverser<K,V,U> {
6108	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
6109	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6110	>	U result;
6111	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
6112	>	MapReduceMappingsTask
6113	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6114	>	MapReduceMappingsTask<K,V,U> nextRight,
6115	>	BiFunction<? super K, ? super V, ? extends U> transformer,
6116	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
6117	>	super(m, p, b); this.nextRight = nextRight;
6118	>	this.transformer = transformer;
6119	>	this.reducer = reducer;
6120	>	}
6121	>	public final U getRawResult() { return result; }
6122	>	@SuppressWarnings("unchecked") public final void compute() {
6123	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
6124	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
6125	>	if ((transformer = this.transformer) != null &&
6126	>	(reducer = this.reducer) != null) {
6127	>	for (int b; (b = preSplit()) > 0;)
6128	>	(rights = new MapReduceMappingsTask<K,V,U>
6129	>	(map, this, b, rights, transformer, reducer)).fork();
6130	>	U r = null, u;
6131	>	V v;
6132	>	while ((v = advance()) != null) {
6133	>	if ((u = transformer.apply((K)nextKey, v)) != null)
6134	>	r = (r == null) ? u : reducer.apply(r, u);
6135	>	}
6136	>	result = r;
6137	>	CountedCompleter<?> c;
6138	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6139	>	MapReduceMappingsTask<K,V,U>
6140	>	t = (MapReduceMappingsTask<K,V,U>)c,
6141	>	s = t.rights;
6142	>	while (s != null) {
6143	>	U tr, sr;
6144	>	if ((sr = s.result) != null)
6145	>	t.result = (((tr = t.result) == null) ? sr :
6146	>	reducer.apply(tr, sr));
6147	>	s = t.rights = s.nextRight;
6148	>	}
6149	>	}
6150	>	}
6151	>	}
6152	>	}
6153	>
6154	>	@SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V>
6155	>	extends Traverser<K,V,Double> {
6156	>	final DoubleFunction<? super K> transformer;
6157	>	final DoubleBinaryOperator reducer;
6158	>	final double basis;
6159	>	double result;
6160	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
6161	>	MapReduceKeysToDoubleTask
6162	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6163	>	MapReduceKeysToDoubleTask<K,V> nextRight,
6164	>	DoubleFunction<? super K> transformer,
6165	>	double basis,
6166	>	DoubleBinaryOperator reducer) {
6167	>	super(m, p, b); this.nextRight = nextRight;
6168	>	this.transformer = transformer;
6169	>	this.basis = basis; this.reducer = reducer;
6170	>	}
6171	>	public final Double getRawResult() { return result; }
6172	>	@SuppressWarnings("unchecked") public final void compute() {
6173	>	final DoubleFunction<? super K> transformer;
6174	>	final DoubleBinaryOperator reducer;
6175	>	if ((transformer = this.transformer) != null &&
6176	>	(reducer = this.reducer) != null) {
6177	>	double r = this.basis;
6178	>	for (int b; (b = preSplit()) > 0;)
6179	>	(rights = new MapReduceKeysToDoubleTask<K,V>
6180	>	(map, this, b, rights, transformer, r, reducer)).fork();
6181	>	while (advance() != null)
6182	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble((K)nextKey));
6183	>	result = r;
6184	>	CountedCompleter<?> c;
6185	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6186	>	MapReduceKeysToDoubleTask<K,V>
6187	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
6188	>	s = t.rights;
6189	>	while (s != null) {
6190	>	t.result = reducer.applyAsDouble(t.result, s.result);
6191	>	s = t.rights = s.nextRight;
6192	>	}
6193	>	}
6194	>	}
6195	>	}
6196	>	}
6197	>
6198	>	@SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V>
6199	>	extends Traverser<K,V,Double> {
6200	>	final DoubleFunction<? super V> transformer;
6201	>	final DoubleBinaryOperator reducer;
6202	>	final double basis;
6203	>	double result;
6204	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
6205	>	MapReduceValuesToDoubleTask
6206	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6207	>	MapReduceValuesToDoubleTask<K,V> nextRight,
6208	>	DoubleFunction<? super V> transformer,
6209	>	double basis,
6210	>	DoubleBinaryOperator reducer) {
6211	>	super(m, p, b); this.nextRight = nextRight;
6212	>	this.transformer = transformer;
6213	>	this.basis = basis; this.reducer = reducer;
6214	>	}
6215	>	public final Double getRawResult() { return result; }
6216	>	@SuppressWarnings("unchecked") public final void compute() {
6217	>	final DoubleFunction<? super V> transformer;
6218	>	final DoubleBinaryOperator reducer;
6219	>	if ((transformer = this.transformer) != null &&
6220	>	(reducer = this.reducer) != null) {
6221	>	double r = this.basis;
6222	>	for (int b; (b = preSplit()) > 0;)
6223	>	(rights = new MapReduceValuesToDoubleTask<K,V>
6224	>	(map, this, b, rights, transformer, r, reducer)).fork();
6225	>	V v;
6226	>	while ((v = advance()) != null)
6227	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(v));
6228	>	result = r;
6229	>	CountedCompleter<?> c;
6230	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6231	>	MapReduceValuesToDoubleTask<K,V>
6232	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
6233	>	s = t.rights;
6234	>	while (s != null) {
6235	>	t.result = reducer.applyAsDouble(t.result, s.result);
6236	>	s = t.rights = s.nextRight;
6237	>	}
6238	>	}
6239	>	}
6240	>	}
6241	>	}
6242	>
6243	>	@SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V>
6244	>	extends Traverser<K,V,Double> {
6245	>	final DoubleFunction<Map.Entry<K,V>> transformer;
6246	>	final DoubleBinaryOperator reducer;
6247	>	final double basis;
6248	>	double result;
6249	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
6250	>	MapReduceEntriesToDoubleTask
6251	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6252	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
6253	>	DoubleFunction<Map.Entry<K,V>> transformer,
6254	>	double basis,
6255	>	DoubleBinaryOperator reducer) {
6256	>	super(m, p, b); this.nextRight = nextRight;
6257	>	this.transformer = transformer;
6258	>	this.basis = basis; this.reducer = reducer;
6259	>	}
6260	>	public final Double getRawResult() { return result; }
6261	>	@SuppressWarnings("unchecked") public final void compute() {
6262	>	final DoubleFunction<Map.Entry<K,V>> transformer;
6263	>	final DoubleBinaryOperator reducer;
6264	>	if ((transformer = this.transformer) != null &&
6265	>	(reducer = this.reducer) != null) {
6266	>	double r = this.basis;
6267	>	for (int b; (b = preSplit()) > 0;)
6268	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
6269	>	(map, this, b, rights, transformer, r, reducer)).fork();
6270	>	V v;
6271	>	while ((v = advance()) != null)
6272	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(entryFor((K)nextKey,
6273	>	v)));
6274	>	result = r;
6275	>	CountedCompleter<?> c;
6276	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6277	>	MapReduceEntriesToDoubleTask<K,V>
6278	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
6279	>	s = t.rights;
6280	>	while (s != null) {
6281	>	t.result = reducer.applyAsDouble(t.result, s.result);
6282	>	s = t.rights = s.nextRight;
6283	>	}
6284	>	}
6285	>	}
6286	>	}
6287	>	}
6288	>
6289	>	@SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V>
6290	>	extends Traverser<K,V,Double> {
6291	>	final DoubleBiFunction<? super K, ? super V> transformer;
6292	>	final DoubleBinaryOperator reducer;
6293	>	final double basis;
6294	>	double result;
6295	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
6296	>	MapReduceMappingsToDoubleTask
6297	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6298	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
6299	>	DoubleBiFunction<? super K, ? super V> transformer,
6300	>	double basis,
6301	>	DoubleBinaryOperator reducer) {
6302	>	super(m, p, b); this.nextRight = nextRight;
6303	>	this.transformer = transformer;
6304	>	this.basis = basis; this.reducer = reducer;
6305	>	}
6306	>	public final Double getRawResult() { return result; }
6307	>	@SuppressWarnings("unchecked") public final void compute() {
6308	>	final DoubleBiFunction<? super K, ? super V> transformer;
6309	>	final DoubleBinaryOperator reducer;
6310	>	if ((transformer = this.transformer) != null &&
6311	>	(reducer = this.reducer) != null) {
6312	>	double r = this.basis;
6313	>	for (int b; (b = preSplit()) > 0;)
6314	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
6315	>	(map, this, b, rights, transformer, r, reducer)).fork();
6316	>	V v;
6317	>	while ((v = advance()) != null)
6318	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble((K)nextKey, v));
6319	>	result = r;
6320	>	CountedCompleter<?> c;
6321	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6322	>	MapReduceMappingsToDoubleTask<K,V>
6323	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
6324	>	s = t.rights;
6325	>	while (s != null) {
6326	>	t.result = reducer.applyAsDouble(t.result, s.result);
6327	>	s = t.rights = s.nextRight;
6328	>	}
6329	>	}
6330	>	}
6331	>	}
6332	>	}
6333	>
6334	>	@SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V>
6335	>	extends Traverser<K,V,Long> {
6336	>	final LongFunction<? super K> transformer;
6337	>	final LongBinaryOperator reducer;
6338	>	final long basis;
6339	>	long result;
6340	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
6341	>	MapReduceKeysToLongTask
6342	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6343	>	MapReduceKeysToLongTask<K,V> nextRight,
6344	>	LongFunction<? super K> transformer,
6345	>	long basis,
6346	>	LongBinaryOperator reducer) {
6347	>	super(m, p, b); this.nextRight = nextRight;
6348	>	this.transformer = transformer;
6349	>	this.basis = basis; this.reducer = reducer;
6350	>	}
6351	>	public final Long getRawResult() { return result; }
6352	>	@SuppressWarnings("unchecked") public final void compute() {
6353	>	final LongFunction<? super K> transformer;
6354	>	final LongBinaryOperator reducer;
6355	>	if ((transformer = this.transformer) != null &&
6356	>	(reducer = this.reducer) != null) {
6357	>	long r = this.basis;
6358	>	for (int b; (b = preSplit()) > 0;)
6359	>	(rights = new MapReduceKeysToLongTask<K,V>
6360	>	(map, this, b, rights, transformer, r, reducer)).fork();
6361	>	while (advance() != null)
6362	>	r = reducer.applyAsLong(r, transformer.applyAsLong((K)nextKey));
6363	>	result = r;
6364	>	CountedCompleter<?> c;
6365	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6366	>	MapReduceKeysToLongTask<K,V>
6367	>	t = (MapReduceKeysToLongTask<K,V>)c,
6368	>	s = t.rights;
6369	>	while (s != null) {
6370	>	t.result = reducer.applyAsLong(t.result, s.result);
6371	>	s = t.rights = s.nextRight;
6372	>	}
6373	>	}
6374	>	}
6375	>	}
6376	>	}
6377	>
6378	>	@SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V>
6379	>	extends Traverser<K,V,Long> {
6380	>	final LongFunction<? super V> transformer;
6381	>	final LongBinaryOperator reducer;
6382	>	final long basis;
6383	>	long result;
6384	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
6385	>	MapReduceValuesToLongTask
6386	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6387	>	MapReduceValuesToLongTask<K,V> nextRight,
6388	>	LongFunction<? super V> transformer,
6389	>	long basis,
6390	>	LongBinaryOperator reducer) {
6391	>	super(m, p, b); this.nextRight = nextRight;
6392	>	this.transformer = transformer;
6393	>	this.basis = basis; this.reducer = reducer;
6394	>	}
6395	>	public final Long getRawResult() { return result; }
6396	>	@SuppressWarnings("unchecked") public final void compute() {
6397	>	final LongFunction<? super V> transformer;
6398	>	final LongBinaryOperator reducer;
6399	>	if ((transformer = this.transformer) != null &&
6400	>	(reducer = this.reducer) != null) {
6401	>	long r = this.basis;
6402	>	for (int b; (b = preSplit()) > 0;)
6403	>	(rights = new MapReduceValuesToLongTask<K,V>
6404	>	(map, this, b, rights, transformer, r, reducer)).fork();
6405	>	V v;
6406	>	while ((v = advance()) != null)
6407	>	r = reducer.applyAsLong(r, transformer.applyAsLong(v));
6408	>	result = r;
6409	>	CountedCompleter<?> c;
6410	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6411	>	MapReduceValuesToLongTask<K,V>
6412	>	t = (MapReduceValuesToLongTask<K,V>)c,
6413	>	s = t.rights;
6414	>	while (s != null) {
6415	>	t.result = reducer.applyAsLong(t.result, s.result);
6416	>	s = t.rights = s.nextRight;
6417	>	}
6418	>	}
6419	>	}
6420	>	}
6421	>	}
6422	>
6423	>	@SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V>
6424	>	extends Traverser<K,V,Long> {
6425	>	final LongFunction<Map.Entry<K,V>> transformer;
6426	>	final LongBinaryOperator reducer;
6427	>	final long basis;
6428	>	long result;
6429	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
6430	>	MapReduceEntriesToLongTask
6431	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6432	>	MapReduceEntriesToLongTask<K,V> nextRight,
6433	>	LongFunction<Map.Entry<K,V>> transformer,
6434	>	long basis,
6435	>	LongBinaryOperator reducer) {
6436	>	super(m, p, b); this.nextRight = nextRight;
6437	>	this.transformer = transformer;
6438	>	this.basis = basis; this.reducer = reducer;
6439	>	}
6440	>	public final Long getRawResult() { return result; }
6441	>	@SuppressWarnings("unchecked") public final void compute() {
6442	>	final LongFunction<Map.Entry<K,V>> transformer;
6443	>	final LongBinaryOperator reducer;
6444	>	if ((transformer = this.transformer) != null &&
6445	>	(reducer = this.reducer) != null) {
6446	>	long r = this.basis;
6447	>	for (int b; (b = preSplit()) > 0;)
6448	>	(rights = new MapReduceEntriesToLongTask<K,V>
6449	>	(map, this, b, rights, transformer, r, reducer)).fork();
6450	>	V v;
6451	>	while ((v = advance()) != null)
6452	>	r = reducer.applyAsLong(r, transformer.applyAsLong(entryFor((K)nextKey, v)));
6453	>	result = r;
6454	>	CountedCompleter<?> c;
6455	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6456	>	MapReduceEntriesToLongTask<K,V>
6457	>	t = (MapReduceEntriesToLongTask<K,V>)c,
6458	>	s = t.rights;
6459	>	while (s != null) {
6460	>	t.result = reducer.applyAsLong(t.result, s.result);
6461	>	s = t.rights = s.nextRight;
6462	>	}
6463	>	}
6464	>	}
6465	>	}
6466	>	}
6467	>
6468	>	@SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V>
6469	>	extends Traverser<K,V,Long> {
6470	>	final LongBiFunction<? super K, ? super V> transformer;
6471	>	final LongBinaryOperator reducer;
6472	>	final long basis;
6473	>	long result;
6474	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6475	>	MapReduceMappingsToLongTask
6476	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6477	>	MapReduceMappingsToLongTask<K,V> nextRight,
6478	>	LongBiFunction<? super K, ? super V> transformer,
6479	>	long basis,
6480	>	LongBinaryOperator reducer) {
6481	>	super(m, p, b); this.nextRight = nextRight;
6482	>	this.transformer = transformer;
6483	>	this.basis = basis; this.reducer = reducer;
6484	>	}
6485	>	public final Long getRawResult() { return result; }
6486	>	@SuppressWarnings("unchecked") public final void compute() {
6487	>	final LongBiFunction<? super K, ? super V> transformer;
6488	>	final LongBinaryOperator reducer;
6489	>	if ((transformer = this.transformer) != null &&
6490	>	(reducer = this.reducer) != null) {
6491	>	long r = this.basis;
6492	>	for (int b; (b = preSplit()) > 0;)
6493	>	(rights = new MapReduceMappingsToLongTask<K,V>
6494	>	(map, this, b, rights, transformer, r, reducer)).fork();
6495	>	V v;
6496	>	while ((v = advance()) != null)
6497	>	r = reducer.applyAsLong(r, transformer.applyAsLong((K)nextKey, v));
6498	>	result = r;
6499	>	CountedCompleter<?> c;
6500	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6501	>	MapReduceMappingsToLongTask<K,V>
6502	>	t = (MapReduceMappingsToLongTask<K,V>)c,
6503	>	s = t.rights;
6504	>	while (s != null) {
6505	>	t.result = reducer.applyAsLong(t.result, s.result);
6506	>	s = t.rights = s.nextRight;
6507	>	}
6508	>	}
6509	>	}
6510	>	}
6511	>	}
6512	>
6513	>	@SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V>
6514	>	extends Traverser<K,V,Integer> {
6515	>	final IntFunction<? super K> transformer;
6516	>	final IntBinaryOperator reducer;
6517	>	final int basis;
6518	>	int result;
6519	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6520	>	MapReduceKeysToIntTask
6521	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6522	>	MapReduceKeysToIntTask<K,V> nextRight,
6523	>	IntFunction<? super K> transformer,
6524	>	int basis,
6525	>	IntBinaryOperator reducer) {
6526	>	super(m, p, b); this.nextRight = nextRight;
6527	>	this.transformer = transformer;
6528	>	this.basis = basis; this.reducer = reducer;
6529	>	}
6530	>	public final Integer getRawResult() { return result; }
6531	>	@SuppressWarnings("unchecked") public final void compute() {
6532	>	final IntFunction<? super K> transformer;
6533	>	final IntBinaryOperator reducer;
6534	>	if ((transformer = this.transformer) != null &&
6535	>	(reducer = this.reducer) != null) {
6536	>	int r = this.basis;
6537	>	for (int b; (b = preSplit()) > 0;)
6538	>	(rights = new MapReduceKeysToIntTask<K,V>
6539	>	(map, this, b, rights, transformer, r, reducer)).fork();
6540	>	while (advance() != null)
6541	>	r = reducer.applyAsInt(r, transformer.applyAsInt((K)nextKey));
6542	>	result = r;
6543	>	CountedCompleter<?> c;
6544	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6545	>	MapReduceKeysToIntTask<K,V>
6546	>	t = (MapReduceKeysToIntTask<K,V>)c,
6547	>	s = t.rights;
6548	>	while (s != null) {
6549	>	t.result = reducer.applyAsInt(t.result, s.result);
6550	>	s = t.rights = s.nextRight;
6551	>	}
6552	>	}
6553	>	}
6554	>	}
6555	>	}
6556	>
6557	>	@SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V>
6558	>	extends Traverser<K,V,Integer> {
6559	>	final IntFunction<? super V> transformer;
6560	>	final IntBinaryOperator reducer;
6561	>	final int basis;
6562	>	int result;
6563	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6564	>	MapReduceValuesToIntTask
6565	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6566	>	MapReduceValuesToIntTask<K,V> nextRight,
6567	>	IntFunction<? super V> transformer,
6568	>	int basis,
6569	>	IntBinaryOperator reducer) {
6570	>	super(m, p, b); this.nextRight = nextRight;
6571	>	this.transformer = transformer;
6572	>	this.basis = basis; this.reducer = reducer;
6573	>	}
6574	>	public final Integer getRawResult() { return result; }
6575	>	@SuppressWarnings("unchecked") public final void compute() {
6576	>	final IntFunction<? super V> transformer;
6577	>	final IntBinaryOperator reducer;
6578	>	if ((transformer = this.transformer) != null &&
6579	>	(reducer = this.reducer) != null) {
6580	>	int r = this.basis;
6581	>	for (int b; (b = preSplit()) > 0;)
6582	>	(rights = new MapReduceValuesToIntTask<K,V>
6583	>	(map, this, b, rights, transformer, r, reducer)).fork();
6584	>	V v;
6585	>	while ((v = advance()) != null)
6586	>	r = reducer.applyAsInt(r, transformer.applyAsInt(v));
6587	>	result = r;
6588	>	CountedCompleter<?> c;
6589	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6590	>	MapReduceValuesToIntTask<K,V>
6591	>	t = (MapReduceValuesToIntTask<K,V>)c,
6592	>	s = t.rights;
6593	>	while (s != null) {
6594	>	t.result = reducer.applyAsInt(t.result, s.result);
6595	>	s = t.rights = s.nextRight;
6596	>	}
6597	>	}
6598	>	}
6599	>	}
6600	>	}
6601	>
6602	>	@SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V>
6603	>	extends Traverser<K,V,Integer> {
6604	>	final IntFunction<Map.Entry<K,V>> transformer;
6605	>	final IntBinaryOperator reducer;
6606	>	final int basis;
6607	>	int result;
6608	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6609	>	MapReduceEntriesToIntTask
6610	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6611	>	MapReduceEntriesToIntTask<K,V> nextRight,
6612	>	IntFunction<Map.Entry<K,V>> transformer,
6613	>	int basis,
6614	>	IntBinaryOperator reducer) {
6615	>	super(m, p, b); this.nextRight = nextRight;
6616	>	this.transformer = transformer;
6617	>	this.basis = basis; this.reducer = reducer;
6618	>	}
6619	>	public final Integer getRawResult() { return result; }
6620	>	@SuppressWarnings("unchecked") public final void compute() {
6621	>	final IntFunction<Map.Entry<K,V>> transformer;
6622	>	final IntBinaryOperator reducer;
6623	>	if ((transformer = this.transformer) != null &&
6624	>	(reducer = this.reducer) != null) {
6625	>	int r = this.basis;
6626	>	for (int b; (b = preSplit()) > 0;)
6627	>	(rights = new MapReduceEntriesToIntTask<K,V>
6628	>	(map, this, b, rights, transformer, r, reducer)).fork();
6629	>	V v;
6630	>	while ((v = advance()) != null)
6631	>	r = reducer.applyAsInt(r, transformer.applyAsInt(entryFor((K)nextKey,
6632	>	v)));
6633	>	result = r;
6634	>	CountedCompleter<?> c;
6635	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6636	>	MapReduceEntriesToIntTask<K,V>
6637	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6638	>	s = t.rights;
6639	>	while (s != null) {
6640	>	t.result = reducer.applyAsInt(t.result, s.result);
6641	>	s = t.rights = s.nextRight;
6642	>	}
6643	>	}
6644	>	}
6645	>	}
6646	>	}
6647	>
6648	>	@SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V>
6649	>	extends Traverser<K,V,Integer> {
6650	>	final IntBiFunction<? super K, ? super V> transformer;
6651	>	final IntBinaryOperator reducer;
6652	>	final int basis;
6653	>	int result;
6654	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6655	>	MapReduceMappingsToIntTask
6656	>	(ConcurrentHashMap<K,V> m, Traverser<K,V,?> p, int b,
6657	>	MapReduceMappingsToIntTask<K,V> nextRight,
6658	>	IntBiFunction<? super K, ? super V> transformer,
6659	>	int basis,
6660	>	IntBinaryOperator reducer) {
6661	>	super(m, p, b); this.nextRight = nextRight;
6662	>	this.transformer = transformer;
6663	>	this.basis = basis; this.reducer = reducer;
6664	>	}
6665	>	public final Integer getRawResult() { return result; }
6666	>	@SuppressWarnings("unchecked") public final void compute() {
6667	>	final IntBiFunction<? super K, ? super V> transformer;
6668	>	final IntBinaryOperator reducer;
6669	>	if ((transformer = this.transformer) != null &&
6670	>	(reducer = this.reducer) != null) {
6671	>	int r = this.basis;
6672	>	for (int b; (b = preSplit()) > 0;)
6673	>	(rights = new MapReduceMappingsToIntTask<K,V>
6674	>	(map, this, b, rights, transformer, r, reducer)).fork();
6675	>	V v;
6676	>	while ((v = advance()) != null)
6677	>	r = reducer.applyAsInt(r, transformer.applyAsInt((K)nextKey, v));
6678	>	result = r;
6679	>	CountedCompleter<?> c;
6680	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6681	>	MapReduceMappingsToIntTask<K,V>
6682	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6683	>	s = t.rights;
6684	>	while (s != null) {
6685	>	t.result = reducer.applyAsInt(t.result, s.result);
6686	>	s = t.rights = s.nextRight;
6687	>	}
6688	>	}
6689	>	}
6690		}
6691		}
6692
6693		// Unsafe mechanics
6694	<	private static final sun.misc.Unsafe UNSAFE;
6695	<	private static final long SBASE;
6696	<	private static final int SSHIFT;
6697	<	private static final long TBASE;
6698	<	private static final int TSHIFT;
6694	>	private static final sun.misc.Unsafe U;
6695	>	private static final long SIZECTL;
6696	>	private static final long TRANSFERINDEX;
6697	>	private static final long TRANSFERORIGIN;
6698	>	private static final long BASECOUNT;
6699	>	private static final long CELLSBUSY;
6700	>	private static final long CELLVALUE;
6701	>	private static final long ABASE;
6702	>	private static final int ASHIFT;
6703
6704		static {
6705	<	int ss, ts;
6705	>	int ss;
6706		try {
6707	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
6708	<	Class<?> tc = HashEntry[].class;
6709	<	Class<?> sc = Segment[].class;
6710	<	TBASE = UNSAFE.arrayBaseOffset(tc);
6711	<	SBASE = UNSAFE.arrayBaseOffset(sc);
6712	<	ts = UNSAFE.arrayIndexScale(tc);
6713	<	ss = UNSAFE.arrayIndexScale(sc);
6707	>	U = sun.misc.Unsafe.getUnsafe();
6708	>	Class<?> k = ConcurrentHashMap.class;
6709	>	SIZECTL = U.objectFieldOffset
6710	>	(k.getDeclaredField("sizeCtl"));
6711	>	TRANSFERINDEX = U.objectFieldOffset
6712	>	(k.getDeclaredField("transferIndex"));
6713	>	TRANSFERORIGIN = U.objectFieldOffset
6714	>	(k.getDeclaredField("transferOrigin"));
6715	>	BASECOUNT = U.objectFieldOffset
6716	>	(k.getDeclaredField("baseCount"));
6717	>	CELLSBUSY = U.objectFieldOffset
6718	>	(k.getDeclaredField("cellsBusy"));
6719	>	Class<?> ck = Cell.class;
6720	>	CELLVALUE = U.objectFieldOffset
6721	>	(ck.getDeclaredField("value"));
6722	>	Class<?> sc = Node[].class;
6723	>	ABASE = U.arrayBaseOffset(sc);
6724	>	ss = U.arrayIndexScale(sc);
6725	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(ss);
6726		} catch (Exception e) {
6727		throw new Error(e);
6728		}
6729	<	if ((ss & (ss-1)) != 0 || (ts & (ts-1)) != 0)
6729	>	if ((ss & (ss-1)) != 0)
6730		throw new Error("data type scale not a power of two");
1481	–	SSHIFT = 31 - Integer.numberOfLeadingZeros(ss);
1482	–	TSHIFT = 31 - Integer.numberOfLeadingZeros(ts);
6731		}
6732
6733		}

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