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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.110 by jsr166, Wed Apr 27 14:06:30 2011 UTC vs.
Revision 1.221 by jsr166, Wed Jun 5 16:00:55 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.io.Serializable;
9	<	import java.io.IOException;
10	<	import java.io.ObjectInputStream;
11	<	import java.io.ObjectOutputStream;
9	>	import java.io.ObjectStreamField;
10	>	import java.lang.reflect.ParameterizedType;
11	>	import java.lang.reflect.Type;
12	>	import java.util.Arrays;
13	>	import java.util.Collection;
14	>	import java.util.Comparator;
15	>	import java.util.ConcurrentModificationException;
16	>	import java.util.Enumeration;
17	>	import java.util.HashMap;
18	>	import java.util.Hashtable;
19	>	import java.util.Iterator;
20	>	import java.util.Map;
21	>	import java.util.NoSuchElementException;
22	>	import java.util.Set;
23	>	import java.util.Spliterator;
24	>	import java.util.concurrent.ConcurrentMap;
25	>	import java.util.concurrent.ForkJoinPool;
26	>	import java.util.concurrent.atomic.AtomicReference;
27	>	import java.util.concurrent.locks.ReentrantLock;
28	>	import java.util.concurrent.locks.StampedLock;
29	>	import java.util.function.BiConsumer;
30	>	import java.util.function.BiFunction;
31	>	import java.util.function.BinaryOperator;
32	>	import java.util.function.Consumer;
33	>	import java.util.function.DoubleBinaryOperator;
34	>	import java.util.function.Function;
35	>	import java.util.function.IntBinaryOperator;
36	>	import java.util.function.LongBinaryOperator;
37	>	import java.util.function.ToDoubleBiFunction;
38	>	import java.util.function.ToDoubleFunction;
39	>	import java.util.function.ToIntBiFunction;
40	>	import java.util.function.ToIntFunction;
41	>	import java.util.function.ToLongBiFunction;
42	>	import java.util.function.ToLongFunction;
43	>	import java.util.stream.Stream;
44
45		/**
46		* A hash table supporting full concurrency of retrievals and
47	<	* adjustable expected concurrency for updates. This class obeys the
47	>	* high expected concurrency for updates. This class obeys the
48		* same functional specification as {@link java.util.Hashtable}, and
49		* includes versions of methods corresponding to each method of
50	<	* <tt>Hashtable</tt>. However, even though all operations are
50	>	* {@code Hashtable}. However, even though all operations are
51		* thread-safe, retrieval operations do <em>not</em> entail locking,
52		* and there is <em>not</em> any support for locking the entire table
53		* in a way that prevents all access.  This class is fully
54	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
54	>	* interoperable with {@code Hashtable} in programs that rely on its
55		* thread safety but not on its synchronization details.
56		*
57	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
58	<	* block, so may overlap with update operations (including
59	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
60	<	* of the most recently <em>completed</em> update operations holding
61	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
62	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
63	<	* removal of only some entries.  Similarly, Iterators and
64	<	* Enumerations return elements reflecting the state of the hash table
65	<	* at some point at or since the creation of the iterator/enumeration.
66	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
67	<	* However, iterators are designed to be used by only one thread at a time.
68	<	*
69	<	* <p> The allowed concurrency among update operations is guided by
70	<	* the optional <tt>concurrencyLevel</tt> constructor argument
71	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
72	<	* table is internally partitioned to try to permit the indicated
73	<	* number of concurrent updates without contention. Because placement
74	<	* in hash tables is essentially random, the actual concurrency will
75	<	* vary.  Ideally, you should choose a value to accommodate as many
76	<	* threads as will ever concurrently modify the table. Using a
77	<	* significantly higher value than you need can waste space and time,
78	<	* and a significantly lower value can lead to thread contention. But
79	<	* overestimates and underestimates within an order of magnitude do
80	<	* not usually have much noticeable impact. A value of one is
81	<	* appropriate when it is known that only one thread will modify and
82	<	* all others will only read. Also, resizing this or any other kind of
83	<	* hash table is a relatively slow operation, so, when possible, it is
84	<	* a good idea to provide estimates of expected table sizes in
85	<	* constructors.
57	>	* <p>Retrieval operations (including {@code get}) generally do not
58	>	* block, so may overlap with update operations (including {@code put}
59	>	* and {@code remove}). Retrievals reflect the results of the most
60	>	* recently <em>completed</em> update operations holding upon their
61	>	* onset. (More formally, an update operation for a given key bears a
62	>	* <em>happens-before</em> relation with any (non-null) retrieval for
63	>	* that key reporting the updated value.)  For aggregate operations
64	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
65	>	* reflect insertion or removal of only some entries.  Similarly,
66	>	* Iterators and Enumerations return elements reflecting the state of
67	>	* the hash table at some point at or since the creation of the
68	>	* iterator/enumeration.  They do <em>not</em> throw {@link
69	>	* ConcurrentModificationException}.  However, iterators are designed
70	>	* to be used by only one thread at a time.  Bear in mind that the
71	>	* results of aggregate status methods including {@code size}, {@code
72	>	* isEmpty}, and {@code containsValue} are typically useful only when
73	>	* a map is not undergoing concurrent updates in other threads.
74	>	* Otherwise the results of these methods reflect transient states
75	>	* that may be adequate for monitoring or estimation purposes, but not
76	>	* for program control.
77	>	*
78	>	* <p>The table is dynamically expanded when there are too many
79	>	* collisions (i.e., keys that have distinct hash codes but fall into
80	>	* the same slot modulo the table size), with the expected average
81	>	* effect of maintaining roughly two bins per mapping (corresponding
82	>	* to a 0.75 load factor threshold for resizing). There may be much
83	>	* variance around this average as mappings are added and removed, but
84	>	* overall, this maintains a commonly accepted time/space tradeoff for
85	>	* hash tables.  However, resizing this or any other kind of hash
86	>	* table may be a relatively slow operation. When possible, it is a
87	>	* good idea to provide a size estimate as an optional {@code
88	>	* initialCapacity} constructor argument. An additional optional
89	>	* {@code loadFactor} constructor argument provides a further means of
90	>	* customizing initial table capacity by specifying the table density
91	>	* to be used in calculating the amount of space to allocate for the
92	>	* given number of elements.  Also, for compatibility with previous
93	>	* versions of this class, constructors may optionally specify an
94	>	* expected {@code concurrencyLevel} as an additional hint for
95	>	* internal sizing.  Note that using many keys with exactly the same
96	>	* {@code hashCode()} is a sure way to slow down performance of any
97	>	* hash table. To ameliorate impact, when keys are {@link Comparable},
98	>	* this class may use comparison order among keys to help break ties.
99	>	*
100	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
101	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
102	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
103	>	* mapped values are (perhaps transiently) not used or all take the
104	>	* same mapping value.
105	>	*
106	>	* <p>A ConcurrentHashMap can be used as scalable frequency map (a
107	>	* form of histogram or multiset) by using {@link
108	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
109	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
110	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
111	>	* {@code freqs.computeIfAbsent(k -> new LongAdder()).increment();}
112		*
113		* <p>This class and its views and iterators implement all of the
114		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
115		* interfaces.
116		*
117	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
118	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
117	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
118	>	* does <em>not</em> allow {@code null} to be used as a key or value.
119	>	*
120	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
121	>	* operations that, unlike most {@link Stream} methods, are designed
122	>	* to be safely, and often sensibly, applied even with maps that are
123	>	* being concurrently updated by other threads; for example, when
124	>	* computing a snapshot summary of the values in a shared registry.
125	>	* There are three kinds of operation, each with four forms, accepting
126	>	* functions with Keys, Values, Entries, and (Key, Value) arguments
127	>	* and/or return values. Because the elements of a ConcurrentHashMap
128	>	* are not ordered in any particular way, and may be processed in
129	>	* different orders in different parallel executions, the correctness
130	>	* of supplied functions should not depend on any ordering, or on any
131	>	* other objects or values that may transiently change while
132	>	* computation is in progress; and except for forEach actions, should
133	>	* ideally be side-effect-free. Bulk operations on {@link Map.Entry}
134	>	* objects do not support method {@code setValue}.
135	>	*
136	>	* <ul>
137	>	* <li> forEach: Perform a given action on each element.
138	>	* A variant form applies a given transformation on each element
139	>	* before performing the action.</li>
140	>	*
141	>	* <li> search: Return the first available non-null result of
142	>	* applying a given function on each element; skipping further
143	>	* search when a result is found.</li>
144	>	*
145	>	* <li> reduce: Accumulate each element.  The supplied reduction
146	>	* function cannot rely on ordering (more formally, it should be
147	>	* both associative and commutative).  There are five variants:
148	>	*
149	>	* <ul>
150	>	*
151	>	* <li> Plain reductions. (There is not a form of this method for
152	>	* (key, value) function arguments since there is no corresponding
153	>	* return type.)</li>
154	>	*
155	>	* <li> Mapped reductions that accumulate the results of a given
156	>	* function applied to each element.</li>
157	>	*
158	>	* <li> Reductions to scalar doubles, longs, and ints, using a
159	>	* given basis value.</li>
160	>	*
161	>	* </ul>
162	>	* </li>
163	>	* </ul>
164	>	*
165	>	* <p>These bulk operations accept a {@code parallelismThreshold}
166	>	* argument. Methods proceed sequentially if the current map size is
167	>	* estimated to be less than the given threshold. Using a value of
168	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
169	>	* of {@code 1} results in maximal parallelism by partitioning into
170	>	* enough subtasks to fully utilize the {@link
171	>	* ForkJoinPool#commonPool()} that is used for all parallel
172	>	* computations. Normally, you would initially choose one of these
173	>	* extreme values, and then measure performance of using in-between
174	>	* values that trade off overhead versus throughput.
175	>	*
176	>	* <p>The concurrency properties of bulk operations follow
177	>	* from those of ConcurrentHashMap: Any non-null result returned
178	>	* from {@code get(key)} and related access methods bears a
179	>	* happens-before relation with the associated insertion or
180	>	* update.  The result of any bulk operation reflects the
181	>	* composition of these per-element relations (but is not
182	>	* necessarily atomic with respect to the map as a whole unless it
183	>	* is somehow known to be quiescent).  Conversely, because keys
184	>	* and values in the map are never null, null serves as a reliable
185	>	* atomic indicator of the current lack of any result.  To
186	>	* maintain this property, null serves as an implicit basis for
187	>	* all non-scalar reduction operations. For the double, long, and
188	>	* int versions, the basis should be one that, when combined with
189	>	* any other value, returns that other value (more formally, it
190	>	* should be the identity element for the reduction). Most common
191	>	* reductions have these properties; for example, computing a sum
192	>	* with basis 0 or a minimum with basis MAX_VALUE.
193	>	*
194	>	* <p>Search and transformation functions provided as arguments
195	>	* should similarly return null to indicate the lack of any result
196	>	* (in which case it is not used). In the case of mapped
197	>	* reductions, this also enables transformations to serve as
198	>	* filters, returning null (or, in the case of primitive
199	>	* specializations, the identity basis) if the element should not
200	>	* be combined. You can create compound transformations and
201	>	* filterings by composing them yourself under this "null means
202	>	* there is nothing there now" rule before using them in search or
203	>	* reduce operations.
204	>	*
205	>	* <p>Methods accepting and/or returning Entry arguments maintain
206	>	* key-value associations. They may be useful for example when
207	>	* finding the key for the greatest value. Note that "plain" Entry
208	>	* arguments can be supplied using {@code new
209	>	* AbstractMap.SimpleEntry(k,v)}.
210	>	*
211	>	* <p>Bulk operations may complete abruptly, throwing an
212	>	* exception encountered in the application of a supplied
213	>	* function. Bear in mind when handling such exceptions that other
214	>	* concurrently executing functions could also have thrown
215	>	* exceptions, or would have done so if the first exception had
216	>	* not occurred.
217	>	*
218	>	* <p>Speedups for parallel compared to sequential forms are common
219	>	* but not guaranteed.  Parallel operations involving brief functions
220	>	* on small maps may execute more slowly than sequential forms if the
221	>	* underlying work to parallelize the computation is more expensive
222	>	* than the computation itself.  Similarly, parallelization may not
223	>	* lead to much actual parallelism if all processors are busy
224	>	* performing unrelated tasks.
225	>	*
226	>	* <p>All arguments to all task methods must be non-null.
227		*
228		* <p>This class is a member of the
229		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
#	Line 70 | Line 234 | import java.io.ObjectOutputStream;
234		* @param <K> the type of keys maintained by this map
235		* @param <V> the type of mapped values
236		*/
237	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
238	<	implements ConcurrentMap<K, V>, Serializable {
237	>	@SuppressWarnings({"unchecked", "rawtypes", "serial"})
238	>	public class ConcurrentHashMap<K,V> implements ConcurrentMap<K,V>, Serializable {
239		private static final long serialVersionUID = 7249069246763182397L;
240
241		/*
242	<	* The basic strategy is to subdivide the table among Segments,
243	<	* each of which itself is a concurrently readable hash table.  To
244	<	* reduce footprint, all but one segments are constructed only
245	<	* when first needed (see ensureSegment). To maintain visibility
246	<	* in the presence of lazy construction, accesses to segments as
247	<	* well as elements of segment's table must use volatile access,
248	<	* which is done via Unsafe within methods segmentAt etc
249	<	* below. These provide the functionality of AtomicReferenceArrays
250	<	* but reduce the levels of indirection. Additionally,
251	<	* volatile-writes of table elements and entry "next" fields
252	<	* within locked operations use the cheaper "lazySet" forms of
253	<	* writes (via putOrderedObject) because these writes are always
254	<	* followed by lock releases that maintain sequential consistency
255	<	* of table updates.
256	<	*
257	<	* Historical note: The previous version of this class relied
258	<	* heavily on "final" fields, which avoided some volatile reads at
259	<	* the expense of a large initial footprint.  Some remnants of
260	<	* that design (including forced construction of segment 0) exist
261	<	* to ensure serialization compatibility.
242	>	* Overview:
243	>	*
244	>	* The primary design goal of this hash table is to maintain
245	>	* concurrent readability (typically method get(), but also
246	>	* iterators and related methods) while minimizing update
247	>	* contention. Secondary goals are to keep space consumption about
248	>	* the same or better than java.util.HashMap, and to support high
249	>	* initial insertion rates on an empty table by many threads.
250	>	*
251	>	* Each key-value mapping is held in a Node.  Because Node key
252	>	* fields can contain special values, they are defined using plain
253	>	* Object types (not type "K"). This leads to a lot of explicit
254	>	* casting (and the use of class-wide warning suppressions).  It
255	>	* also allows some of the public methods to be factored into a
256	>	* smaller number of internal methods (although sadly not so for
257	>	* the five variants of put-related operations). The
258	>	* validation-based approach explained below leads to a lot of
259	>	* code sprawl because retry-control precludes factoring into
260	>	* smaller methods.
261	>	*
262	>	* The table is lazily initialized to a power-of-two size upon the
263	>	* first insertion.  Each bin in the table normally contains a
264	>	* list of Nodes (most often, the list has only zero or one Node).
265	>	* Table accesses require volatile/atomic reads, writes, and
266	>	* CASes.  Because there is no other way to arrange this without
267	>	* adding further indirections, we use intrinsics
268	>	* (sun.misc.Unsafe) operations.
269	>	*
270	>	* We use the top (sign) bit of Node hash fields for control
271	>	* purposes -- it is available anyway because of addressing
272	>	* constraints.  Nodes with negative hash fields are forwarding
273	>	* nodes to either TreeBins or resized tables.  The lower 31 bits
274	>	* of each normal Node's hash field contain a transformation of
275	>	* the key's hash code.
276	>	*
277	>	* Insertion (via put or its variants) of the first node in an
278	>	* empty bin is performed by just CASing it to the bin.  This is
279	>	* by far the most common case for put operations under most
280	>	* key/hash distributions.  Other update operations (insert,
281	>	* delete, and replace) require locks.  We do not want to waste
282	>	* the space required to associate a distinct lock object with
283	>	* each bin, so instead use the first node of a bin list itself as
284	>	* a lock. Locking support for these locks relies on builtin
285	>	* "synchronized" monitors.
286	>	*
287	>	* Using the first node of a list as a lock does not by itself
288	>	* suffice though: When a node is locked, any update must first
289	>	* validate that it is still the first node after locking it, and
290	>	* retry if not. Because new nodes are always appended to lists,
291	>	* once a node is first in a bin, it remains first until deleted
292	>	* or the bin becomes invalidated (upon resizing).
293	>	*
294	>	* The main disadvantage of per-bin locks is that other update
295	>	* operations on other nodes in a bin list protected by the same
296	>	* lock can stall, for example when user equals() or mapping
297	>	* functions take a long time.  However, statistically, under
298	>	* random hash codes, this is not a common problem.  Ideally, the
299	>	* frequency of nodes in bins follows a Poisson distribution
300	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
301	>	* parameter of about 0.5 on average, given the resizing threshold
302	>	* of 0.75, although with a large variance because of resizing
303	>	* granularity. Ignoring variance, the expected occurrences of
304	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
305	>	* first values are:
306	>	*
307	>	* 0:    0.60653066
308	>	* 1:    0.30326533
309	>	* 2:    0.07581633
310	>	* 3:    0.01263606
311	>	* 4:    0.00157952
312	>	* 5:    0.00015795
313	>	* 6:    0.00001316
314	>	* 7:    0.00000094
315	>	* 8:    0.00000006
316	>	* more: less than 1 in ten million
317	>	*
318	>	* Lock contention probability for two threads accessing distinct
319	>	* elements is roughly 1 / (8 * #elements) under random hashes.
320	>	*
321	>	* Actual hash code distributions encountered in practice
322	>	* sometimes deviate significantly from uniform randomness.  This
323	>	* includes the case when N > (1<<30), so some keys MUST collide.
324	>	* Similarly for dumb or hostile usages in which multiple keys are
325	>	* designed to have identical hash codes. Also, although we guard
326	>	* against the worst effects of this (see method spread), sets of
327	>	* hashes may differ only in bits that do not impact their bin
328	>	* index for a given power-of-two mask.  So we use a secondary
329	>	* strategy that applies when the number of nodes in a bin exceeds
330	>	* a threshold, and at least one of the keys implements
331	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
332	>	* (a specialized form of red-black trees), bounding search time
333	>	* to O(log N).  Each search step in a TreeBin is at least twice as
334	>	* slow as in a regular list, but given that N cannot exceed
335	>	* (1<<64) (before running out of addresses) this bounds search
336	>	* steps, lock hold times, etc, to reasonable constants (roughly
337	>	* 100 nodes inspected per operation worst case) so long as keys
338	>	* are Comparable (which is very common -- String, Long, etc).
339	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
340	>	* traversal pointers as regular nodes, so can be traversed in
341	>	* iterators in the same way.
342	>	*
343	>	* The table is resized when occupancy exceeds a percentage
344	>	* threshold (nominally, 0.75, but see below).  Any thread
345	>	* noticing an overfull bin may assist in resizing after the
346	>	* initiating thread allocates and sets up the replacement
347	>	* array. However, rather than stalling, these other threads may
348	>	* proceed with insertions etc.  The use of TreeBins shields us
349	>	* from the worst case effects of overfilling while resizes are in
350	>	* progress.  Resizing proceeds by transferring bins, one by one,
351	>	* from the table to the next table. To enable concurrency, the
352	>	* next table must be (incrementally) prefilled with place-holders
353	>	* serving as reverse forwarders to the old table.  Because we are
354	>	* using power-of-two expansion, the elements from each bin must
355	>	* either stay at same index, or move with a power of two
356	>	* offset. We eliminate unnecessary node creation by catching
357	>	* cases where old nodes can be reused because their next fields
358	>	* won't change.  On average, only about one-sixth of them need
359	>	* cloning when a table doubles. The nodes they replace will be
360	>	* garbage collectable as soon as they are no longer referenced by
361	>	* any reader thread that may be in the midst of concurrently
362	>	* traversing table.  Upon transfer, the old table bin contains
363	>	* only a special forwarding node (with hash field "MOVED") that
364	>	* contains the next table as its key. On encountering a
365	>	* forwarding node, access and update operations restart, using
366	>	* the new table.
367	>	*
368	>	* Each bin transfer requires its bin lock, which can stall
369	>	* waiting for locks while resizing. However, because other
370	>	* threads can join in and help resize rather than contend for
371	>	* locks, average aggregate waits become shorter as resizing
372	>	* progresses.  The transfer operation must also ensure that all
373	>	* accessible bins in both the old and new table are usable by any
374	>	* traversal.  This is arranged by proceeding from the last bin
375	>	* (table.length - 1) up towards the first.  Upon seeing a
376	>	* forwarding node, traversals (see class Traverser) arrange to
377	>	* move to the new table without revisiting nodes.  However, to
378	>	* ensure that no intervening nodes are skipped, bin splitting can
379	>	* only begin after the associated reverse-forwarders are in
380	>	* place.
381	>	*
382	>	* The traversal scheme also applies to partial traversals of
383	>	* ranges of bins (via an alternate Traverser constructor)
384	>	* to support partitioned aggregate operations.  Also, read-only
385	>	* operations give up if ever forwarded to a null table, which
386	>	* provides support for shutdown-style clearing, which is also not
387	>	* currently implemented.
388	>	*
389	>	* Lazy table initialization minimizes footprint until first use,
390	>	* and also avoids resizings when the first operation is from a
391	>	* putAll, constructor with map argument, or deserialization.
392	>	* These cases attempt to override the initial capacity settings,
393	>	* but harmlessly fail to take effect in cases of races.
394	>	*
395	>	* The element count is maintained using a specialization of
396	>	* LongAdder. We need to incorporate a specialization rather than
397	>	* just use a LongAdder in order to access implicit
398	>	* contention-sensing that leads to creation of multiple
399	>	* Cells.  The counter mechanics avoid contention on
400	>	* updates but can encounter cache thrashing if read too
401	>	* frequently during concurrent access. To avoid reading so often,
402	>	* resizing under contention is attempted only upon adding to a
403	>	* bin already holding two or more nodes. Under uniform hash
404	>	* distributions, the probability of this occurring at threshold
405	>	* is around 13%, meaning that only about 1 in 8 puts check
406	>	* threshold (and after resizing, many fewer do so). The bulk
407	>	* putAll operation further reduces contention by only committing
408	>	* count updates upon these size checks.
409	>	*
410	>	* Maintaining API and serialization compatibility with previous
411	>	* versions of this class introduces several oddities. Mainly: We
412	>	* leave untouched but unused constructor arguments refering to
413	>	* concurrencyLevel. We accept a loadFactor constructor argument,
414	>	* but apply it only to initial table capacity (which is the only
415	>	* time that we can guarantee to honor it.) We also declare an
416	>	* unused "Segment" class that is instantiated in minimal form
417	>	* only when serializing.
418		*/
419
420		/* ---------------- Constants -------------- */
421
422		/**
423	<	* The default initial capacity for this table,
424	<	* used when not otherwise specified in a constructor.
423	>	* The largest possible table capacity.  This value must be
424	>	* exactly 1<<30 to stay within Java array allocation and indexing
425	>	* bounds for power of two table sizes, and is further required
426	>	* because the top two bits of 32bit hash fields are used for
427	>	* control purposes.
428		*/
429	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
429	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
430
431		/**
432	<	* The default load factor for this table, used when not
433	<	* otherwise specified in a constructor.
432	>	* The default initial table capacity.  Must be a power of 2
433	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
434		*/
435	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
435	>	private static final int DEFAULT_CAPACITY = 16;
436
437		/**
438	<	* The default concurrency level for this table, used when not
439	<	* otherwise specified in a constructor.
438	>	* The largest possible (non-power of two) array size.
439	>	* Needed by toArray and related methods.
440		*/
441	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
441	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
442
443		/**
444	<	* The maximum capacity, used if a higher value is implicitly
445	<	* specified by either of the constructors with arguments.  MUST
123	<	* be a power of two <= 1<<30 to ensure that entries are indexable
124	<	* using ints.
444	>	* The default concurrency level for this table. Unused but
445	>	* defined for compatibility with previous versions of this class.
446		*/
447	<	static final int MAXIMUM_CAPACITY = 1 << 30;
447	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
448
449		/**
450	<	* The minimum capacity for per-segment tables.  Must be a power
451	<	* of two, at least two to avoid immediate resizing on next use
452	<	* after lazy construction.
450	>	* The load factor for this table. Overrides of this value in
451	>	* constructors affect only the initial table capacity.  The
452	>	* actual floating point value isn't normally used -- it is
453	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
454	>	* the associated resizing threshold.
455		*/
456	<	static final int MIN_SEGMENT_TABLE_CAPACITY = 2;
456	>	private static final float LOAD_FACTOR = 0.75f;
457
458		/**
459	<	* The maximum number of segments to allow; used to bound
460	<	* constructor arguments. Must be power of two less than 1 << 24.
459	>	* The bin count threshold for using a tree rather than list for a
460	>	* bin.  The value reflects the approximate break-even point for
461	>	* using tree-based operations.
462	>	*/
463	>	private static final int TREE_THRESHOLD = 8;
464	>
465	>	/**
466	>	* Minimum number of rebinnings per transfer step. Ranges are
467	>	* subdivided to allow multiple resizer threads.  This value
468	>	* serves as a lower bound to avoid resizers encountering
469	>	* excessive memory contention.  The value should be at least
470	>	* DEFAULT_CAPACITY.
471	>	*/
472	>	private static final int MIN_TRANSFER_STRIDE = 16;
473	>
474	>	/*
475	>	* Encodings for Node hash fields. See above for explanation.
476		*/
477	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
477	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
478	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
479	>
480	>	/** Number of CPUS, to place bounds on some sizings */
481	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
482	>
483	>	/** For serialization compatibility. */
484	>	private static final ObjectStreamField[] serialPersistentFields = {
485	>	new ObjectStreamField("segments", Segment[].class),
486	>	new ObjectStreamField("segmentMask", Integer.TYPE),
487	>	new ObjectStreamField("segmentShift", Integer.TYPE)
488	>	};
489
490		/**
491	<	* Number of unsynchronized retries in size and containsValue
492	<	* methods before resorting to locking. This is used to avoid
144	<	* unbounded retries if tables undergo continuous modification
145	<	* which would make it impossible to obtain an accurate result.
491	>	* A padded cell for distributing counts.  Adapted from LongAdder
492	>	* and Striped64.  See their internal docs for explanation.
493		*/
494	<	static final int RETRIES_BEFORE_LOCK = 2;
494	>	@sun.misc.Contended static final class Cell {
495	>	volatile long value;
496	>	Cell(long x) { value = x; }
497	>	}
498
499		/* ---------------- Fields -------------- */
500
501		/**
502	<	* Mask value for indexing into segments. The upper bits of a
503	<	* key's hash code are used to choose the segment.
502	>	* The array of bins. Lazily initialized upon first insertion.
503	>	* Size is always a power of two. Accessed directly by iterators.
504	>	*/
505	>	transient volatile Node<K,V>[] table;
506	>
507	>	/**
508	>	* The next table to use; non-null only while resizing.
509	>	*/
510	>	private transient volatile Node<K,V>[] nextTable;
511	>
512	>	/**
513	>	* Base counter value, used mainly when there is no contention,
514	>	* but also as a fallback during table initialization
515	>	* races. Updated via CAS.
516		*/
517	<	final int segmentMask;
517	>	private transient volatile long baseCount;
518
519		/**
520	<	* Shift value for indexing within segments.
520	>	* Table initialization and resizing control.  When negative, the
521	>	* table is being initialized or resized: -1 for initialization,
522	>	* else -(1 + the number of active resizing threads).  Otherwise,
523	>	* when table is null, holds the initial table size to use upon
524	>	* creation, or 0 for default. After initialization, holds the
525	>	* next element count value upon which to resize the table.
526		*/
527	<	final int segmentShift;
527	>	private transient volatile int sizeCtl;
528
529		/**
530	<	* The segments, each of which is a specialized hash table.
530	>	* The next table index (plus one) to split while resizing.
531		*/
532	<	final Segment<K,V>[] segments;
532	>	private transient volatile int transferIndex;
533
534	<	transient Set<K> keySet;
535	<	transient Set<Map.Entry<K,V>> entrySet;
536	<	transient Collection<V> values;
534	>	/**
535	>	* The least available table index to split while resizing.
536	>	*/
537	>	private transient volatile int transferOrigin;
538	>
539	>	/**
540	>	* Spinlock (locked via CAS) used when resizing and/or creating Cells.
541	>	*/
542	>	private transient volatile int cellsBusy;
543
544		/**
545	<	* ConcurrentHashMap list entry. Note that this is never exported
173	<	* out as a user-visible Map.Entry.
545	>	* Table of counter cells. When non-null, size is a power of 2.
546		*/
547	<	static final class HashEntry<K,V> {
547	>	private transient volatile Cell[] counterCells;
548	>
549	>	// views
550	>	private transient KeySetView<K,V> keySet;
551	>	private transient ValuesView<K,V> values;
552	>	private transient EntrySetView<K,V> entrySet;
553	>
554	>	/* ---------------- Table element access -------------- */
555	>
556	>	/*
557	>	* Volatile access methods are used for table elements as well as
558	>	* elements of in-progress next table while resizing.  Uses are
559	>	* null checked by callers, and implicitly bounds-checked, relying
560	>	* on the invariants that tab arrays have non-zero size, and all
561	>	* indices are masked with (tab.length - 1) which is never
562	>	* negative and always less than length. Note that, to be correct
563	>	* wrt arbitrary concurrency errors by users, bounds checks must
564	>	* operate on local variables, which accounts for some odd-looking
565	>	* inline assignments below.
566	>	*/
567	>
568	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
569	>	return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
570	>	}
571	>
572	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
573	>	Node<K,V> c, Node<K,V> v) {
574	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
575	>	}
576	>
577	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
578	>	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
579	>	}
580	>
581	>	/* ---------------- Nodes -------------- */
582	>
583	>	/**
584	>	* Key-value entry.  This class is never exported out as a
585	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
586	>	* MapEntry below), but can be used for read-only traversals used
587	>	* in bulk tasks.  Nodes with a hash field of MOVED are special,
588	>	* and do not contain user keys or values (and are never
589	>	* exported).  Otherwise, keys and vals are never null.
590	>	*/
591	>	static class Node<K,V> implements Map.Entry<K,V> {
592		final int hash;
593	<	final K key;
594	<	volatile V value;
595	<	volatile HashEntry<K,V> next;
593	>	final Object key;
594	>	volatile V val;
595	>	Node<K,V> next;
596
597	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
597	>	Node(int hash, Object key, V val, Node<K,V> next) {
598		this.hash = hash;
599		this.key = key;
600	<	this.value = value;
600	>	this.val = val;
601		this.next = next;
602		}
603
604	<	/**
605	<	* Sets next field with volatile write semantics.  (See above
606	<	* about use of putOrderedObject.)
607	<	*/
608	<	final void setNext(HashEntry<K,V> n) {
609	<	UNSAFE.putOrderedObject(this, nextOffset, n);
604	>	public final K getKey()       { return (K)key; }
605	>	public final V getValue()     { return val; }
606	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
607	>	public final String toString(){ return key + "=" + val; }
608	>	public final V setValue(V value) {
609	>	throw new UnsupportedOperationException();
610		}
611
612	<	// Unsafe mechanics
613	<	static final sun.misc.Unsafe UNSAFE;
614	<	static final long nextOffset;
615	<	static {
616	<	try {
617	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
618	<	Class k = HashEntry.class;
203	<	nextOffset = UNSAFE.objectFieldOffset
204	<	(k.getDeclaredField("next"));
205	<	} catch (Exception e) {
206	<	throw new Error(e);
207	<	}
612	>	public final boolean equals(Object o) {
613	>	Object k, v, u; Map.Entry<?,?> e;
614	>	return ((o instanceof Map.Entry) &&
615	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
616	>	(v = e.getValue()) != null &&
617	>	(k == key || k.equals(key)) &&
618	>	(v == (u = val) || v.equals(u)));
619		}
620		}
621
622		/**
623	<	* Gets the ith element of given table (if nonnull) with volatile
213	<	* read semantics. Note: This is manually integrated into a few
214	<	* performance-sensitive methods to reduce call overhead.
623	>	* Exported Entry for EntryIterator
624		*/
625	<	@SuppressWarnings("unchecked")
626	<	static final <K,V> HashEntry<K,V> entryAt(HashEntry<K,V>[] tab, int i) {
627	<	return (tab == null) ? null :
628	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
629	<	(tab, ((long)i << TSHIFT) + TBASE);
625	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
626	>	final K key; // non-null
627	>	V val;       // non-null
628	>	final ConcurrentHashMap<K,V> map;
629	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
630	>	this.key = key;
631	>	this.val = val;
632	>	this.map = map;
633	>	}
634	>	public K getKey()        { return key; }
635	>	public V getValue()      { return val; }
636	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
637	>	public String toString() { return key + "=" + val; }
638	>
639	>	public boolean equals(Object o) {
640	>	Object k, v; Map.Entry<?,?> e;
641	>	return ((o instanceof Map.Entry) &&
642	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
643	>	(v = e.getValue()) != null &&
644	>	(k == key || k.equals(key)) &&
645	>	(v == val || v.equals(val)));
646	>	}
647	>
648	>	/**
649	>	* Sets our entry's value and writes through to the map. The
650	>	* value to return is somewhat arbitrary here. Since we do not
651	>	* necessarily track asynchronous changes, the most recent
652	>	* "previous" value could be different from what we return (or
653	>	* could even have been removed, in which case the put will
654	>	* re-establish). We do not and cannot guarantee more.
655	>	*/
656	>	public V setValue(V value) {
657	>	if (value == null) throw new NullPointerException();
658	>	V v = val;
659	>	val = value;
660	>	map.put(key, value);
661	>	return v;
662	>	}
663		}
664
665	+
666	+	/* ---------------- TreeBins -------------- */
667	+
668		/**
669	<	* Sets the ith element of given table, with volatile write
225	<	* semantics. (See above about use of putOrderedObject.)
669	>	* Nodes for use in TreeBins
670		*/
671	<	static final <K,V> void setEntryAt(HashEntry<K,V>[] tab, int i,
672	<	HashEntry<K,V> e) {
673	<	UNSAFE.putOrderedObject(tab, ((long)i << TSHIFT) + TBASE, e);
671	>	static final class TreeNode<K,V> extends Node<K,V> {
672	>	TreeNode<K,V> parent;  // red-black tree links
673	>	TreeNode<K,V> left;
674	>	TreeNode<K,V> right;
675	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
676	>	boolean red;
677	>
678	>	TreeNode(int hash, Object key, V val, Node<K,V> next,
679	>	TreeNode<K,V> parent) {
680	>	super(hash, key, val, next);
681	>	this.parent = parent;
682	>	}
683		}
684
685		/**
686	<	* Applies a supplemental hash function to a given hashCode, which
687	<	* defends against poor quality hash functions.  This is critical
688	<	* because ConcurrentHashMap uses power-of-two length hash tables,
689	<	* that otherwise encounter collisions for hashCodes that do not
690	<	* differ in lower or upper bits.
691	<	*/
692	<	private static int hash(int h) {
693	<	// Spread bits to regularize both segment and index locations,
694	<	// using variant of single-word Wang/Jenkins hash.
695	<	h += (h <<  15) ^ 0xffffcd7d;
696	<	h ^= (h >>> 10);
697	<	h += (h <<   3);
698	<	h ^= (h >>>  6);
699	<	h += (h <<   2) + (h << 14);
700	<	return h ^ (h >>> 16);
686	>	* Returns a Class for the given type of the form "class C
687	>	* implements Comparable<C>", if one exists, else null.  See below
688	>	* for explanation.
689	>	*/
690	>	static Class<?> comparableClassFor(Class<?> c) {
691	>	Class<?> s, cmpc; Type[] ts, as; Type t; ParameterizedType p;
692	>	if (c == String.class) // bypass checks
693	>	return c;
694	>	if (c != null && (cmpc = Comparable.class).isAssignableFrom(c)) {
695	>	while (cmpc.isAssignableFrom(s = c.getSuperclass()))
696	>	c = s; // find topmost comparable class
697	>	if ((ts = c.getGenericInterfaces()) != null) {
698	>	for (int i = 0; i < ts.length; ++i) {
699	>	if (((t = ts[i]) instanceof ParameterizedType) &&
700	>	((p = (ParameterizedType)t).getRawType() == cmpc) &&
701	>	(as = p.getActualTypeArguments()) != null &&
702	>	as.length == 1 && as[0] == c) // type arg is c
703	>	return c;
704	>	}
705	>	}
706	>	}
707	>	return null;
708		}
709
710		/**
711	<	* Segments are specialized versions of hash tables.  This
712	<	* subclasses from ReentrantLock opportunistically, just to
713	<	* simplify some locking and avoid separate construction.
711	>	* A specialized form of red-black tree for use in bins
712	>	* whose size exceeds a threshold.
713	>	*
714	>	* TreeBins use a special form of comparison for search and
715	>	* related operations (which is the main reason we cannot use
716	>	* existing collections such as TreeMaps). TreeBins contain
717	>	* Comparable elements, but may contain others, as well as
718	>	* elements that are Comparable but not necessarily Comparable
719	>	* for the same T, so we cannot invoke compareTo among them. To
720	>	* handle this, the tree is ordered primarily by hash value, then
721	>	* by Comparable.compareTo order if applicable.  On lookup at a
722	>	* node, if elements are not comparable or compare as 0 then both
723	>	* left and right children may need to be searched in the case of
724	>	* tied hash values. (This corresponds to the full list search
725	>	* that would be necessary if all elements were non-Comparable and
726	>	* had tied hashes.)  The red-black balancing code is updated from
727	>	* pre-jdk-collections
728	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
729	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
730	>	* Algorithms" (CLR).
731	>	*
732	>	* TreeBins also maintain a separate locking discipline than
733	>	* regular bins. Because they are forwarded via special MOVED
734	>	* nodes at bin heads (which can never change once established),
735	>	* we cannot use those nodes as locks. Instead, TreeBin extends
736	>	* StampedLock to support a form of read-write lock. For update
737	>	* operations and table validation, the exclusive form of lock
738	>	* behaves in the same way as bin-head locks. However, lookups use
739	>	* shared read-lock mechanics to allow multiple readers in the
740	>	* absence of writers.  Additionally, these lookups do not ever
741	>	* block: While the lock is not available, they proceed along the
742	>	* slow traversal path (via next-pointers) until the lock becomes
743	>	* available or the list is exhausted, whichever comes
744	>	* first. These cases are not fast, but maximize aggregate
745	>	* expected throughput.
746		*/
747	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
256	<	/*
257	<	* Segments maintain a table of entry lists that are always
258	<	* kept in a consistent state, so can be read (via volatile
259	<	* reads of segments and tables) without locking.  This
260	<	* requires replicating nodes when necessary during table
261	<	* resizing, so the old lists can be traversed by readers
262	<	* still using old version of table.
263	<	*
264	<	* This class defines only mutative methods requiring locking.
265	<	* Except as noted, the methods of this class perform the
266	<	* per-segment versions of ConcurrentHashMap methods.  (Other
267	<	* methods are integrated directly into ConcurrentHashMap
268	<	* methods.) These mutative methods use a form of controlled
269	<	* spinning on contention via methods scanAndLock and
270	<	* scanAndLockForPut. These intersperse tryLocks with
271	<	* traversals to locate nodes.  The main benefit is to absorb
272	<	* cache misses (which are very common for hash tables) while
273	<	* obtaining locks so that traversal is faster once
274	<	* acquired. We do not actually use the found nodes since they
275	<	* must be re-acquired under lock anyway to ensure sequential
276	<	* consistency of updates (and in any case may be undetectably
277	<	* stale), but they will normally be much faster to re-locate.
278	<	* Also, scanAndLockForPut speculatively creates a fresh node
279	<	* to use in put if no node is found.
280	<	*/
281	<
747	>	static final class TreeBin<K,V> extends StampedLock {
748		private static final long serialVersionUID = 2249069246763182397L;
749	+	transient TreeNode<K,V> root;  // root of tree
750	+	transient TreeNode<K,V> first; // head of next-pointer list
751	+
752	+	/** From CLR */
753	+	private void rotateLeft(TreeNode<K,V> p) {
754	+	if (p != null) {
755	+	TreeNode<K,V> r = p.right, pp, rl;
756	+	if ((rl = p.right = r.left) != null)
757	+	rl.parent = p;
758	+	if ((pp = r.parent = p.parent) == null)
759	+	root = r;
760	+	else if (pp.left == p)
761	+	pp.left = r;
762	+	else
763	+	pp.right = r;
764	+	r.left = p;
765	+	p.parent = r;
766	+	}
767	+	}
768	+
769	+	/** From CLR */
770	+	private void rotateRight(TreeNode<K,V> p) {
771	+	if (p != null) {
772	+	TreeNode<K,V> l = p.left, pp, lr;
773	+	if ((lr = p.left = l.right) != null)
774	+	lr.parent = p;
775	+	if ((pp = l.parent = p.parent) == null)
776	+	root = l;
777	+	else if (pp.right == p)
778	+	pp.right = l;
779	+	else
780	+	pp.left = l;
781	+	l.right = p;
782	+	p.parent = l;
783	+	}
784	+	}
785
786		/**
787	<	* The maximum number of times to tryLock in a prescan before
788	<	* possibly blocking on acquire in preparation for a locked
287	<	* segment operation. On multiprocessors, using a bounded
288	<	* number of retries maintains cache acquired while locating
289	<	* nodes.
787	>	* Returns the TreeNode (or null if not found) for the given key
788	>	* starting at given root.
789		*/
790	<	static final int MAX_SCAN_RETRIES =
791	<	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
790	>	final TreeNode<K,V> getTreeNode(int h, Object k, TreeNode<K,V> p,
791	>	Class<?> cc) {
792	>	while (p != null) {
793	>	int dir, ph; Object pk; Class<?> pc;
794	>	if ((ph = p.hash) != h)
795	>	dir = (h < ph) ? -1 : 1;
796	>	else if ((pk = p.key) == k || k.equals(pk))
797	>	return p;
798	>	else if (cc == null || pk == null ||
799	>	((pc = pk.getClass()) != cc &&
800	>	comparableClassFor(pc) != cc) ||
801	>	(dir = ((Comparable<Object>)k).compareTo(pk)) == 0) {
802	>	TreeNode<K,V> r, pr; // check both sides
803	>	if ((pr = p.right) != null &&
804	>	(r = getTreeNode(h, k, pr, cc)) != null)
805	>	return r;
806	>	else // continue left
807	>	dir = -1;
808	>	}
809	>	p = (dir > 0) ? p.right : p.left;
810	>	}
811	>	return null;
812	>	}
813
814		/**
815	<	* The per-segment table. Elements are accessed via
816	<	* entryAt/setEntryAt providing volatile semantics.
815	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
816	>	* read-lock to call getTreeNode, but during failure to get
817	>	* lock, searches along next links.
818		*/
819	<	transient volatile HashEntry<K,V>[] table;
819	>	final V getValue(int h, Object k) {
820	>	Class<?> cc = comparableClassFor(k.getClass());
821	>	Node<K,V> r = null;
822	>	for (Node<K,V> e = first; e != null; e = e.next) {
823	>	long s;
824	>	if ((s = tryReadLock()) != 0L) {
825	>	try {
826	>	r = getTreeNode(h, k, root, cc);
827	>	} finally {
828	>	unlockRead(s);
829	>	}
830	>	break;
831	>	}
832	>	else if (e.hash == h && k.equals(e.key)) {
833	>	r = e;
834	>	break;
835	>	}
836	>	}
837	>	return r == null ? null : r.val;
838	>	}
839
840		/**
841	<	* The number of elements. Accessed only either within locks
842	<	* or among other volatile reads that maintain visibility.
841	>	* Finds or adds a node.
842	>	* @return null if added
843		*/
844	<	transient int count;
844	>	final TreeNode<K,V> putTreeNode(int h, Object k, V v) {
845	>	Class<?> cc = comparableClassFor(k.getClass());
846	>	TreeNode<K,V> pp = root, p = null;
847	>	int dir = 0;
848	>	while (pp != null) { // find existing node or leaf to insert at
849	>	int ph; Object pk; Class<?> pc;
850	>	p = pp;
851	>	if ((ph = p.hash) != h)
852	>	dir = (h < ph) ? -1 : 1;
853	>	else if ((pk = p.key) == k || k.equals(pk))
854	>	return p;
855	>	else if (cc == null || pk == null ||
856	>	((pc = pk.getClass()) != cc &&
857	>	comparableClassFor(pc) != cc) ||
858	>	(dir = ((Comparable<Object>)k).compareTo(pk)) == 0) {
859	>	TreeNode<K,V> r, pr;
860	>	if ((pr = p.right) != null &&
861	>	(r = getTreeNode(h, k, pr, cc)) != null)
862	>	return r;
863	>	else // continue left
864	>	dir = -1;
865	>	}
866	>	pp = (dir > 0) ? p.right : p.left;
867	>	}
868	>
869	>	TreeNode<K,V> f = first;
870	>	TreeNode<K,V> x = first = new TreeNode<K,V>(h, k, v, f, p);
871	>	if (p == null)
872	>	root = x;
873	>	else { // attach and rebalance; adapted from CLR
874	>	if (f != null)
875	>	f.prev = x;
876	>	if (dir <= 0)
877	>	p.left = x;
878	>	else
879	>	p.right = x;
880	>	x.red = true;
881	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
882	>	if ((xp = x.parent) == null) {
883	>	(root = x).red = false;
884	>	break;
885	>	}
886	>	else if (!xp.red || (xpp = xp.parent) == null) {
887	>	TreeNode<K,V> r = root;
888	>	if (r != null && r.red)
889	>	r.red = false;
890	>	break;
891	>	}
892	>	else if ((xppl = xpp.left) == xp) {
893	>	if ((xppr = xpp.right) != null && xppr.red) {
894	>	xppr.red = false;
895	>	xp.red = false;
896	>	xpp.red = true;
897	>	x = xpp;
898	>	}
899	>	else {
900	>	if (x == xp.right) {
901	>	rotateLeft(x = xp);
902	>	xpp = (xp = x.parent) == null ? null : xp.parent;
903	>	}
904	>	if (xp != null) {
905	>	xp.red = false;
906	>	if (xpp != null) {
907	>	xpp.red = true;
908	>	rotateRight(xpp);
909	>	}
910	>	}
911	>	}
912	>	}
913	>	else {
914	>	if (xppl != null && xppl.red) {
915	>	xppl.red = false;
916	>	xp.red = false;
917	>	xpp.red = true;
918	>	x = xpp;
919	>	}
920	>	else {
921	>	if (x == xp.left) {
922	>	rotateRight(x = xp);
923	>	xpp = (xp = x.parent) == null ? null : xp.parent;
924	>	}
925	>	if (xp != null) {
926	>	xp.red = false;
927	>	if (xpp != null) {
928	>	xpp.red = true;
929	>	rotateLeft(xpp);
930	>	}
931	>	}
932	>	}
933	>	}
934	>	}
935	>	}
936	>	assert checkInvariants();
937	>	return null;
938	>	}
939
940		/**
941	<	* The total number of mutative operations in this segment.
942	<	* Even though this may overflows 32 bits, it provides
943	<	* sufficient accuracy for stability checks in CHM isEmpty()
944	<	* and size() methods.  Accessed only either within locks or
945	<	* among other volatile reads that maintain visibility.
941	>	* Removes the given node, that must be present before this
942	>	* call.  This is messier than typical red-black deletion code
943	>	* because we cannot swap the contents of an interior node
944	>	* with a leaf successor that is pinned by "next" pointers
945	>	* that are accessible independently of lock. So instead we
946	>	* swap the tree linkages.
947		*/
948	<	transient int modCount;
948	>	final void deleteTreeNode(TreeNode<K,V> p) {
949	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
950	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
951	>	if (pred == null)
952	>	first = next;
953	>	else
954	>	pred.next = next;
955	>	if (next != null)
956	>	next.prev = pred;
957	>	else if (pred == null) {
958	>	root = null;
959	>	return;
960	>	}
961	>	TreeNode<K,V> replacement;
962	>	TreeNode<K,V> pl = p.left;
963	>	TreeNode<K,V> pr = p.right;
964	>	if (pl != null && pr != null) {
965	>	TreeNode<K,V> s = pr, sl;
966	>	while ((sl = s.left) != null) // find successor
967	>	s = sl;
968	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
969	>	TreeNode<K,V> sr = s.right;
970	>	TreeNode<K,V> pp = p.parent;
971	>	if (s == pr) { // p was s's direct parent
972	>	p.parent = s;
973	>	s.right = p;
974	>	}
975	>	else {
976	>	TreeNode<K,V> sp = s.parent;
977	>	if ((p.parent = sp) != null) {
978	>	if (s == sp.left)
979	>	sp.left = p;
980	>	else
981	>	sp.right = p;
982	>	}
983	>	if ((s.right = pr) != null)
984	>	pr.parent = s;
985	>	}
986	>	p.left = null;
987	>	if ((p.right = sr) != null)
988	>	sr.parent = p;
989	>	if ((s.left = pl) != null)
990	>	pl.parent = s;
991	>	if ((s.parent = pp) == null)
992	>	root = s;
993	>	else if (p == pp.left)
994	>	pp.left = s;
995	>	else
996	>	pp.right = s;
997	>	if (sr != null)
998	>	replacement = sr;
999	>	else
1000	>	replacement = p;
1001	>	}
1002	>	else if (pl != null)
1003	>	replacement = pl;
1004	>	else if (pr != null)
1005	>	replacement = pr;
1006	>	else
1007	>	replacement = p;
1008	>	if (replacement != p) {
1009	>	TreeNode<K,V> pp = replacement.parent = p.parent;
1010	>	if (pp == null)
1011	>	root = replacement;
1012	>	else if (p == pp.left)
1013	>	pp.left = replacement;
1014	>	else
1015	>	pp.right = replacement;
1016	>	p.left = p.right = p.parent = null;
1017	>	}
1018	>	if (!p.red) { // rebalance, from CLR
1019	>	for (TreeNode<K,V> x = replacement; x != null; ) {
1020	>	TreeNode<K,V> xp, xpl, xpr;
1021	>	if (x.red || (xp = x.parent) == null) {
1022	>	x.red = false;
1023	>	break;
1024	>	}
1025	>	else if ((xpl = xp.left) == x) {
1026	>	if ((xpr = xp.right) != null && xpr.red) {
1027	>	xpr.red = false;
1028	>	xp.red = true;
1029	>	rotateLeft(xp);
1030	>	xpr = (xp = x.parent) == null ? null : xp.right;
1031	>	}
1032	>	if (xpr == null)
1033	>	x = xp;
1034	>	else {
1035	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
1036	>	if ((sr == null || !sr.red) &&
1037	>	(sl == null || !sl.red)) {
1038	>	xpr.red = true;
1039	>	x = xp;
1040	>	}
1041	>	else {
1042	>	if (sr == null || !sr.red) {
1043	>	if (sl != null)
1044	>	sl.red = false;
1045	>	xpr.red = true;
1046	>	rotateRight(xpr);
1047	>	xpr = (xp = x.parent) == null ?
1048	>	null : xp.right;
1049	>	}
1050	>	if (xpr != null) {
1051	>	xpr.red = (xp == null) ? false : xp.red;
1052	>	if ((sr = xpr.right) != null)
1053	>	sr.red = false;
1054	>	}
1055	>	if (xp != null) {
1056	>	xp.red = false;
1057	>	rotateLeft(xp);
1058	>	}
1059	>	x = root;
1060	>	}
1061	>	}
1062	>	}
1063	>	else { // symmetric
1064	>	if (xpl != null && xpl.red) {
1065	>	xpl.red = false;
1066	>	xp.red = true;
1067	>	rotateRight(xp);
1068	>	xpl = (xp = x.parent) == null ? null : xp.left;
1069	>	}
1070	>	if (xpl == null)
1071	>	x = xp;
1072	>	else {
1073	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
1074	>	if ((sl == null || !sl.red) &&
1075	>	(sr == null || !sr.red)) {
1076	>	xpl.red = true;
1077	>	x = xp;
1078	>	}
1079	>	else {
1080	>	if (sl == null || !sl.red) {
1081	>	if (sr != null)
1082	>	sr.red = false;
1083	>	xpl.red = true;
1084	>	rotateLeft(xpl);
1085	>	xpl = (xp = x.parent) == null ?
1086	>	null : xp.left;
1087	>	}
1088	>	if (xpl != null) {
1089	>	xpl.red = (xp == null) ? false : xp.red;
1090	>	if ((sl = xpl.left) != null)
1091	>	sl.red = false;
1092	>	}
1093	>	if (xp != null) {
1094	>	xp.red = false;
1095	>	rotateRight(xp);
1096	>	}
1097	>	x = root;
1098	>	}
1099	>	}
1100	>	}
1101	>	}
1102	>	}
1103	>	if (p == replacement) {  // detach pointers
1104	>	TreeNode<K,V> pp;
1105	>	if ((pp = p.parent) != null) {
1106	>	if (p == pp.left)
1107	>	pp.left = null;
1108	>	else if (p == pp.right)
1109	>	pp.right = null;
1110	>	p.parent = null;
1111	>	}
1112	>	}
1113	>	assert checkInvariants();
1114	>	}
1115
1116		/**
1117	<	* The table is rehashed when its size exceeds this threshold.
317	<	* (The value of this field is always <tt>(int)(capacity *
318	<	* loadFactor)</tt>.)
1117	>	* Checks linkage and balance invariants at root
1118		*/
1119	<	transient int threshold;
1119	>	final boolean checkInvariants() {
1120	>	TreeNode<K,V> r = root;
1121	>	if (r == null)
1122	>	return (first == null);
1123	>	else
1124	>	return (first != null) && checkTreeNode(r);
1125	>	}
1126
1127		/**
1128	<	* The load factor for the hash table.  Even though this value
324	<	* is same for all segments, it is replicated to avoid needing
325	<	* links to outer object.
326	<	* @serial
1128	>	* Recursive invariant check
1129		*/
1130	<	final float loadFactor;
1130	>	final boolean checkTreeNode(TreeNode<K,V> t) {
1131	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
1132	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
1133	>	if (tb != null && tb.next != t)
1134	>	return false;
1135	>	if (tn != null && tn.prev != t)
1136	>	return false;
1137	>	if (tp != null && t != tp.left && t != tp.right)
1138	>	return false;
1139	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
1140	>	return false;
1141	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
1142	>	return false;
1143	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
1144	>	return false;
1145	>	if (tl != null && !checkTreeNode(tl))
1146	>	return false;
1147	>	if (tr != null && !checkTreeNode(tr))
1148	>	return false;
1149	>	return true;
1150	>	}
1151	>	}
1152	>
1153	>	/* ---------------- Collision reduction methods -------------- */
1154
1155	<	Segment(float lf, int threshold, HashEntry<K,V>[] tab) {
1156	<	this.loadFactor = lf;
1157	<	this.threshold = threshold;
1158	<	this.table = tab;
1155	>	/**
1156	>	* Spreads higher bits to lower, and also forces top bit to 0.
1157	>	* Because the table uses power-of-two masking, sets of hashes
1158	>	* that vary only in bits above the current mask will always
1159	>	* collide. (Among known examples are sets of Float keys holding
1160	>	* consecutive whole numbers in small tables.)  To counter this,
1161	>	* we apply a transform that spreads the impact of higher bits
1162	>	* downward. There is a tradeoff between speed, utility, and
1163	>	* quality of bit-spreading. Because many common sets of hashes
1164	>	* are already reasonably distributed across bits (so don't benefit
1165	>	* from spreading), and because we use trees to handle large sets
1166	>	* of collisions in bins, we don't need excessively high quality.
1167	>	*/
1168	>	private static final int spread(int h) {
1169	>	h ^= (h >>> 18) ^ (h >>> 12);
1170	>	return (h ^ (h >>> 10)) & HASH_BITS;
1171	>	}
1172	>
1173	>	/**
1174	>	* Replaces a list bin with a tree bin if key is comparable.  Call
1175	>	* only when locked.
1176	>	*/
1177	>	private final void replaceWithTreeBin(Node<K,V>[] tab, int index, Object key) {
1178	>	if (tab != null && comparableClassFor(key.getClass()) != null) {
1179	>	TreeBin<K,V> t = new TreeBin<K,V>();
1180	>	for (Node<K,V> e = tabAt(tab, index); e != null; e = e.next)
1181	>	t.putTreeNode(e.hash, e.key, e.val);
1182	>	setTabAt(tab, index, new Node<K,V>(MOVED, t, null, null));
1183		}
1184	+	}
1185
1186	<	final V put(K key, int hash, V value, boolean onlyIfAbsent) {
1187	<	HashEntry<K,V> node = tryLock() ? null :
1188	<	scanAndLockForPut(key, hash, value);
1189	<	V oldValue;
1190	<	try {
1191	<	HashEntry<K,V>[] tab = table;
1192	<	int index = (tab.length - 1) & hash;
1193	<	HashEntry<K,V> first = entryAt(tab, index);
1194	<	for (HashEntry<K,V> e = first;;) {
1195	<	if (e != null) {
1196	<	K k;
1197	<	if ((k = e.key) == key ||
1198	<	(e.hash == hash && key.equals(k))) {
1199	<	oldValue = e.value;
1200	<	if (!onlyIfAbsent) {
1201	<	e.value = value;
1202	<	++modCount;
1186	>	/* ---------------- Internal access and update methods -------------- */
1187	>
1188	>	/** Implementation for get and containsKey */
1189	>	private final V internalGet(Object k) {
1190	>	int h = spread(k.hashCode());
1191	>	V v = null;
1192	>	Node<K,V>[] tab; Node<K,V> e;
1193	>	if ((tab = table) != null &&
1194	>	(e = tabAt(tab, (tab.length - 1) & h)) != null) {
1195	>	for (;;) {
1196	>	int eh; Object ek;
1197	>	if ((eh = e.hash) < 0) {
1198	>	if ((ek = e.key) instanceof TreeBin) { // search TreeBin
1199	>	v = ((TreeBin<K,V>)ek).getValue(h, k);
1200	>	break;
1201	>	}
1202	>	else if (!(ek instanceof Node[]) ||    // try new table
1203	>	(e = tabAt(tab = (Node<K,V>[])ek,
1204	>	(tab.length - 1) & h)) == null)
1205	>	break;
1206	>	}
1207	>	else if (eh == h && ((ek = e.key) == k || k.equals(ek))) {
1208	>	v = e.val;
1209	>	break;
1210	>	}
1211	>	else if ((e = e.next) == null)
1212	>	break;
1213	>	}
1214	>	}
1215	>	return v;
1216	>	}
1217	>
1218	>	/**
1219	>	* Implementation for the four public remove/replace methods:
1220	>	* Replaces node value with v, conditional upon match of cv if
1221	>	* non-null.  If resulting value is null, delete.
1222	>	*/
1223	>	private final V internalReplace(Object k, V v, Object cv) {
1224	>	int h = spread(k.hashCode());
1225	>	V oldVal = null;
1226	>	for (Node<K,V>[] tab = table;;) {
1227	>	Node<K,V> f; int i, fh; Object fk;
1228	>	if (tab == null ||
1229	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1230	>	break;
1231	>	else if ((fh = f.hash) < 0) {
1232	>	if ((fk = f.key) instanceof TreeBin) {
1233	>	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1234	>	long stamp = t.writeLock();
1235	>	boolean validated = false;
1236	>	boolean deleted = false;
1237	>	try {
1238	>	if (tabAt(tab, i) == f) {
1239	>	validated = true;
1240	>	Class<?> cc = comparableClassFor(k.getClass());
1241	>	TreeNode<K,V> p = t.getTreeNode(h, k, t.root, cc);
1242	>	if (p != null) {
1243	>	V pv = p.val;
1244	>	if (cv == null || cv == pv || cv.equals(pv)) {
1245	>	oldVal = pv;
1246	>	if (v != null)
1247	>	p.val = v;
1248	>	else {
1249	>	deleted = true;
1250	>	t.deleteTreeNode(p);
1251	>	}
1252	>	}
1253		}
354	–	break;
1254		}
1255	<	e = e.next;
1255	>	} finally {
1256	>	t.unlockWrite(stamp);
1257		}
1258	<	else {
1259	<	if (node != null)
1260	<	node.setNext(first);
361	<	else
362	<	node = new HashEntry<K,V>(hash, key, value, first);
363	<	int c = count + 1;
364	<	if (c > threshold && tab.length < MAXIMUM_CAPACITY)
365	<	rehash(node);
366	<	else
367	<	setEntryAt(tab, index, node);
368	<	++modCount;
369	<	count = c;
370	<	oldValue = null;
1258	>	if (validated) {
1259	>	if (deleted)
1260	>	addCount(-1L, -1);
1261		break;
1262		}
1263		}
1264	<	} finally {
1265	<	unlock();
1264	>	else
1265	>	tab = (Node<K,V>[])fk;
1266	>	}
1267	>	else {
1268	>	boolean validated = false;
1269	>	boolean deleted = false;
1270	>	synchronized (f) {
1271	>	if (tabAt(tab, i) == f) {
1272	>	validated = true;
1273	>	for (Node<K,V> e = f, pred = null;;) {
1274	>	Object ek;
1275	>	if (e.hash == h &&
1276	>	((ek = e.key) == k || k.equals(ek))) {
1277	>	V ev = e.val;
1278	>	if (cv == null || cv == ev || cv.equals(ev)) {
1279	>	oldVal = ev;
1280	>	if (v != null)
1281	>	e.val = v;
1282	>	else {
1283	>	deleted = true;
1284	>	Node<K,V> en = e.next;
1285	>	if (pred != null)
1286	>	pred.next = en;
1287	>	else
1288	>	setTabAt(tab, i, en);
1289	>	}
1290	>	}
1291	>	break;
1292	>	}
1293	>	pred = e;
1294	>	if ((e = e.next) == null)
1295	>	break;
1296	>	}
1297	>	}
1298	>	}
1299	>	if (validated) {
1300	>	if (deleted)
1301	>	addCount(-1L, -1);
1302	>	break;
1303	>	}
1304		}
377	–	return oldValue;
1305		}
1306	+	return oldVal;
1307	+	}
1308
1309	<	/**
1310	<	* Doubles size of table and repacks entries, also adding the
1311	<	* given node to new table
1312	<	*/
1313	<	@SuppressWarnings("unchecked")
1314	<	private void rehash(HashEntry<K,V> node) {
1315	<	/*
1316	<	* Reclassify nodes in each list to new table.  Because we
1317	<	* are using power-of-two expansion, the elements from
1318	<	* each bin must either stay at same index, or move with a
1319	<	* power of two offset. We eliminate unnecessary node
1320	<	* creation by catching cases where old nodes can be
1321	<	* reused because their next fields won't change.
1322	<	* Statistically, at the default threshold, only about
1323	<	* one-sixth of them need cloning when a table
1324	<	* doubles. The nodes they replace will be garbage
1325	<	* collectable as soon as they are no longer referenced by
1326	<	* any reader thread that may be in the midst of
1327	<	* concurrently traversing table. Entry accesses use plain
1328	<	* array indexing because they are followed by volatile
1329	<	* table write.
1330	<	*/
1331	<	HashEntry<K,V>[] oldTable = table;
1332	<	int oldCapacity = oldTable.length;
1333	<	int newCapacity = oldCapacity << 1;
1334	<	threshold = (int)(newCapacity * loadFactor);
1335	<	HashEntry<K,V>[] newTable =
1336	<	(HashEntry<K,V>[]) new HashEntry[newCapacity];
1337	<	int sizeMask = newCapacity - 1;
1338	<	for (int i = 0; i < oldCapacity ; i++) {
1339	<	HashEntry<K,V> e = oldTable[i];
1340	<	if (e != null) {
1341	<	HashEntry<K,V> next = e.next;
1342	<	int idx = e.hash & sizeMask;
1343	<	if (next == null)   //  Single node on list
1344	<	newTable[idx] = e;
1345	<	else { // Reuse consecutive sequence at same slot
1346	<	HashEntry<K,V> lastRun = e;
1347	<	int lastIdx = idx;
1348	<	for (HashEntry<K,V> last = next;
1349	<	last != null;
1350	<	last = last.next) {
1351	<	int k = last.hash & sizeMask;
1352	<	if (k != lastIdx) {
1353	<	lastIdx = k;
1354	<	lastRun = last;
1355	<	}
1356	<	}
1357	<	newTable[lastIdx] = lastRun;
1358	<	// Clone remaining nodes
1359	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
1360	<	V v = p.value;
1361	<	int h = p.hash;
1362	<	int k = h & sizeMask;
1363	<	HashEntry<K,V> n = newTable[k];
1364	<	newTable[k] = new HashEntry<K,V>(h, p.key, v, n);
1309	>	/*
1310	>	* Internal versions of insertion methods
1311	>	* All have the same basic structure as the first (internalPut):
1312	>	*  1. If table uninitialized, create
1313	>	*  2. If bin empty, try to CAS new node
1314	>	*  3. If bin stale, use new table
1315	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1316	>	*  5. Lock and validate; if valid, scan and add or update
1317	>	*
1318	>	* The putAll method differs mainly in attempting to pre-allocate
1319	>	* enough table space, and also more lazily performs count updates
1320	>	* and checks.
1321	>	*
1322	>	* Most of the function-accepting methods can't be factored nicely
1323	>	* because they require different functional forms, so instead
1324	>	* sprawl out similar mechanics.
1325	>	*/
1326	>
1327	>	/** Implementation for put and putIfAbsent */
1328	>	private final V internalPut(K k, V v, boolean onlyIfAbsent) {
1329	>	if (k == null || v == null) throw new NullPointerException();
1330	>	int h = spread(k.hashCode());
1331	>	int len = 0;
1332	>	for (Node<K,V>[] tab = table;;) {
1333	>	int i, fh; Node<K,V> f; Object fk;
1334	>	if (tab == null)
1335	>	tab = initTable();
1336	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1337	>	if (casTabAt(tab, i, null, new Node<K,V>(h, k, v, null)))
1338	>	break;                   // no lock when adding to empty bin
1339	>	}
1340	>	else if ((fh = f.hash) < 0) {
1341	>	if ((fk = f.key) instanceof TreeBin) {
1342	>	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1343	>	long stamp = t.writeLock();
1344	>	V oldVal = null;
1345	>	try {
1346	>	if (tabAt(tab, i) == f) {
1347	>	len = 2;
1348	>	TreeNode<K,V> p = t.putTreeNode(h, k, v);
1349	>	if (p != null) {
1350	>	oldVal = p.val;
1351	>	if (!onlyIfAbsent)
1352	>	p.val = v;
1353	>	}
1354	>	}
1355	>	} finally {
1356	>	t.unlockWrite(stamp);
1357	>	}
1358	>	if (len != 0) {
1359	>	if (oldVal != null)
1360	>	return oldVal;
1361	>	break;
1362	>	}
1363	>	}
1364	>	else
1365	>	tab = (Node<K,V>[])fk;
1366	>	}
1367	>	else {
1368	>	V oldVal = null;
1369	>	synchronized (f) {
1370	>	if (tabAt(tab, i) == f) {
1371	>	len = 1;
1372	>	for (Node<K,V> e = f;; ++len) {
1373	>	Object ek;
1374	>	if (e.hash == h &&
1375	>	((ek = e.key) == k || k.equals(ek))) {
1376	>	oldVal = e.val;
1377	>	if (!onlyIfAbsent)
1378	>	e.val = v;
1379	>	break;
1380	>	}
1381	>	Node<K,V> last = e;
1382	>	if ((e = e.next) == null) {
1383	>	last.next = new Node<K,V>(h, k, v, null);
1384	>	if (len > TREE_THRESHOLD)
1385	>	replaceWithTreeBin(tab, i, k);
1386	>	break;
1387	>	}
1388		}
1389		}
1390		}
1391	+	if (len != 0) {
1392	+	if (oldVal != null)
1393	+	return oldVal;
1394	+	break;
1395	+	}
1396		}
440	–	int nodeIndex = node.hash & sizeMask; // add the new node
441	–	node.setNext(newTable[nodeIndex]);
442	–	newTable[nodeIndex] = node;
443	–	table = newTable;
1397		}
1398	+	addCount(1L, len);
1399	+	return null;
1400	+	}
1401
1402	<	/**
1403	<	* Scans for a node containing given key while trying to
1404	<	* acquire lock, creating and returning one if not found. Upon
1405	<	* return, guarantees that lock is held. Unlike in most
1406	<	* methods, calls to method equals are not screened: Since
1407	<	* traversal speed doesn't matter, we might as well help warm
1408	<	* up the associated code and accesses as well.
1409	<	*
1410	<	* @return a new node if key not found, else null
1411	<	*/
1412	<	private HashEntry<K,V> scanAndLockForPut(K key, int hash, V value) {
1413	<	HashEntry<K,V> first = entryForHash(this, hash);
1414	<	HashEntry<K,V> e = first;
1415	<	HashEntry<K,V> node = null;
1416	<	int retries = -1; // negative while locating node
1417	<	while (!tryLock()) {
1418	<	HashEntry<K,V> f; // to recheck first below
1419	<	if (retries < 0) {
1420	<	if (e == null) {
1421	<	if (node == null) // speculatively create node
1422	<	node = new HashEntry<K,V>(hash, key, value, null);
1423	<	retries = 0;
1402	>	/** Implementation for computeIfAbsent */
1403	>	private final V internalComputeIfAbsent(K k, Function<? super K, ? extends V> mf) {
1404	>	if (k == null || mf == null)
1405	>	throw new NullPointerException();
1406	>	int h = spread(k.hashCode());
1407	>	V val = null;
1408	>	int len = 0;
1409	>	for (Node<K,V>[] tab = table;;) {
1410	>	Node<K,V> f; int i; Object fk;
1411	>	if (tab == null)
1412	>	tab = initTable();
1413	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1414	>	Node<K,V> node = new Node<K,V>(h, k, null, null);
1415	>	synchronized (node) {
1416	>	if (casTabAt(tab, i, null, node)) {
1417	>	len = 1;
1418	>	try {
1419	>	if ((val = mf.apply(k)) != null)
1420	>	node.val = val;
1421	>	} finally {
1422	>	if (val == null)
1423	>	setTabAt(tab, i, null);
1424	>	}
1425		}
469	–	else if (key.equals(e.key))
470	–	retries = 0;
471	–	else
472	–	e = e.next;
1426		}
1427	<	else if (++retries > MAX_SCAN_RETRIES) {
475	<	lock();
1427	>	if (len != 0)
1428		break;
1429	+	}
1430	+	else if (f.hash < 0) {
1431	+	if ((fk = f.key) instanceof TreeBin) {
1432	+	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1433	+	long stamp = t.writeLock();
1434	+	boolean added = false;
1435	+	try {
1436	+	if (tabAt(tab, i) == f) {
1437	+	len = 2;
1438	+	Class<?> cc = comparableClassFor(k.getClass());
1439	+	TreeNode<K,V> p = t.getTreeNode(h, k, t.root, cc);
1440	+	if (p != null)
1441	+	val = p.val;
1442	+	else if ((val = mf.apply(k)) != null) {
1443	+	added = true;
1444	+	t.putTreeNode(h, k, val);
1445	+	}
1446	+	}
1447	+	} finally {
1448	+	t.unlockWrite(stamp);
1449	+	}
1450	+	if (len != 0) {
1451	+	if (!added)
1452	+	return val;
1453	+	break;
1454	+	}
1455		}
1456	<	else if ((retries & 1) == 0 &&
1457	<	(f = entryForHash(this, hash)) != first) {
1458	<	e = first = f; // re-traverse if entry changed
1459	<	retries = -1;
1456	>	else
1457	>	tab = (Node<K,V>[])fk;
1458	>	}
1459	>	else {
1460	>	boolean added = false;
1461	>	synchronized (f) {
1462	>	if (tabAt(tab, i) == f) {
1463	>	len = 1;
1464	>	for (Node<K,V> e = f;; ++len) {
1465	>	Object ek; V ev;
1466	>	if (e.hash == h &&
1467	>	((ek = e.key) == k || k.equals(ek))) {
1468	>	val = e.val;
1469	>	break;
1470	>	}
1471	>	Node<K,V> last = e;
1472	>	if ((e = e.next) == null) {
1473	>	if ((val = mf.apply(k)) != null) {
1474	>	added = true;
1475	>	last.next = new Node<K,V>(h, k, val, null);
1476	>	if (len > TREE_THRESHOLD)
1477	>	replaceWithTreeBin(tab, i, k);
1478	>	}
1479	>	break;
1480	>	}
1481	>	}
1482	>	}
1483	>	}
1484	>	if (len != 0) {
1485	>	if (!added)
1486	>	return val;
1487	>	break;
1488		}
1489		}
484	–	return node;
1490		}
1491	+	if (val != null)
1492	+	addCount(1L, len);
1493	+	return val;
1494	+	}
1495
1496	<	/**
1497	<	* Scans for a node containing the given key while trying to
1498	<	* acquire lock for a remove or replace operation. Upon
1499	<	* return, guarantees that lock is held.  Note that we must
1500	<	* lock even if the key is not found, to ensure sequential
1501	<	* consistency of updates.
1502	<	*/
1503	<	private void scanAndLock(Object key, int hash) {
1504	<	// similar to but simpler than scanAndLockForPut
1505	<	HashEntry<K,V> first = entryForHash(this, hash);
1506	<	HashEntry<K,V> e = first;
1507	<	int retries = -1;
1508	<	while (!tryLock()) {
1509	<	HashEntry<K,V> f;
1510	<	if (retries < 0) {
1511	<	if (e == null || key.equals(e.key))
1512	<	retries = 0;
1513	<	else
1514	<	e = e.next;
1496	>	/** Implementation for compute */
1497	>	private final V internalCompute(K k, boolean onlyIfPresent,
1498	>	BiFunction<? super K, ? super V, ? extends V> mf) {
1499	>	if (k == null || mf == null)
1500	>	throw new NullPointerException();
1501	>	int h = spread(k.hashCode());
1502	>	V val = null;
1503	>	int delta = 0;
1504	>	int len = 0;
1505	>	for (Node<K,V>[] tab = table;;) {
1506	>	Node<K,V> f; int i, fh; Object fk;
1507	>	if (tab == null)
1508	>	tab = initTable();
1509	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1510	>	if (onlyIfPresent)
1511	>	break;
1512	>	Node<K,V> node = new Node<K,V>(h, k, null, null);
1513	>	synchronized (node) {
1514	>	if (casTabAt(tab, i, null, node)) {
1515	>	try {
1516	>	len = 1;
1517	>	if ((val = mf.apply(k, null)) != null) {
1518	>	node.val = val;
1519	>	delta = 1;
1520	>	}
1521	>	} finally {
1522	>	if (delta == 0)
1523	>	setTabAt(tab, i, null);
1524	>	}
1525	>	}
1526		}
1527	<	else if (++retries > MAX_SCAN_RETRIES) {
508	<	lock();
1527	>	if (len != 0)
1528		break;
1529	+	}
1530	+	else if ((fh = f.hash) < 0) {
1531	+	if ((fk = f.key) instanceof TreeBin) {
1532	+	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1533	+	long stamp = t.writeLock();
1534	+	try {
1535	+	if (tabAt(tab, i) == f) {
1536	+	len = 2;
1537	+	Class<?> cc = comparableClassFor(k.getClass());
1538	+	TreeNode<K,V> p = t.getTreeNode(h, k, t.root, cc);
1539	+	if (p != null || !onlyIfPresent) {
1540	+	V pv = (p == null) ? null : p.val;
1541	+	if ((val = mf.apply(k, pv)) != null) {
1542	+	if (p != null)
1543	+	p.val = val;
1544	+	else {
1545	+	delta = 1;
1546	+	t.putTreeNode(h, k, val);
1547	+	}
1548	+	}
1549	+	else if (p != null) {
1550	+	delta = -1;
1551	+	t.deleteTreeNode(p);
1552	+	}
1553	+	}
1554	+	}
1555	+	} finally {
1556	+	t.unlockWrite(stamp);
1557	+	}
1558	+	if (len != 0)
1559	+	break;
1560		}
1561	<	else if ((retries & 1) == 0 &&
1562	<	(f = entryForHash(this, hash)) != first) {
1563	<	e = first = f;
1564	<	retries = -1;
1561	>	else
1562	>	tab = (Node<K,V>[])fk;
1563	>	}
1564	>	else {
1565	>	synchronized (f) {
1566	>	if (tabAt(tab, i) == f) {
1567	>	len = 1;
1568	>	for (Node<K,V> e = f, pred = null;; ++len) {
1569	>	Object ek;
1570	>	if (e.hash == h &&
1571	>	((ek = e.key) == k || k.equals(ek))) {
1572	>	val = mf.apply(k, e.val);
1573	>	if (val != null)
1574	>	e.val = val;
1575	>	else {
1576	>	delta = -1;
1577	>	Node<K,V> en = e.next;
1578	>	if (pred != null)
1579	>	pred.next = en;
1580	>	else
1581	>	setTabAt(tab, i, en);
1582	>	}
1583	>	break;
1584	>	}
1585	>	pred = e;
1586	>	if ((e = e.next) == null) {
1587	>	if (!onlyIfPresent &&
1588	>	(val = mf.apply(k, null)) != null) {
1589	>	pred.next = new Node<K,V>(h, k, val, null);
1590	>	delta = 1;
1591	>	if (len > TREE_THRESHOLD)
1592	>	replaceWithTreeBin(tab, i, k);
1593	>	}
1594	>	break;
1595	>	}
1596	>	}
1597	>	}
1598		}
1599	+	if (len != 0)
1600	+	break;
1601		}
1602		}
1603	+	if (delta != 0)
1604	+	addCount((long)delta, len);
1605	+	return val;
1606	+	}
1607
1608	<	/**
1609	<	* Remove; match on key only if value null, else match both.
1610	<	*/
1611	<	final V remove(Object key, int hash, Object value) {
1612	<	if (!tryLock())
1613	<	scanAndLock(key, hash);
1614	<	V oldValue = null;
1615	<	try {
1616	<	HashEntry<K,V>[] tab = table;
1617	<	int index = (tab.length - 1) & hash;
1618	<	HashEntry<K,V> e = entryAt(tab, index);
1619	<	HashEntry<K,V> pred = null;
1620	<	while (e != null) {
1621	<	K k;
1622	<	HashEntry<K,V> next = e.next;
1623	<	if ((k = e.key) == key ||
1624	<	(e.hash == hash && key.equals(k))) {
1625	<	V v = e.value;
1626	<	if (value == null || value == v || value.equals(v)) {
1627	<	if (pred == null)
1628	<	setEntryAt(tab, index, next);
1629	<	else
1630	<	pred.setNext(next);
1631	<	++modCount;
1632	<	--count;
1633	<	oldValue = v;
1608	>	/** Implementation for merge */
1609	>	private final V internalMerge(K k, V v,
1610	>	BiFunction<? super V, ? super V, ? extends V> mf) {
1611	>	if (k == null || v == null || mf == null)
1612	>	throw new NullPointerException();
1613	>	int h = spread(k.hashCode());
1614	>	V val = null;
1615	>	int delta = 0;
1616	>	int len = 0;
1617	>	for (Node<K,V>[] tab = table;;) {
1618	>	int i; Node<K,V> f; Object fk;
1619	>	if (tab == null)
1620	>	tab = initTable();
1621	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1622	>	if (casTabAt(tab, i, null, new Node<K,V>(h, k, v, null))) {
1623	>	delta = 1;
1624	>	val = v;
1625	>	break;
1626	>	}
1627	>	}
1628	>	else if (f.hash < 0) {
1629	>	if ((fk = f.key) instanceof TreeBin) {
1630	>	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1631	>	long stamp = t.writeLock();
1632	>	try {
1633	>	if (tabAt(tab, i) == f) {
1634	>	len = 2;
1635	>	Class<?> cc = comparableClassFor(k.getClass());
1636	>	TreeNode<K,V> p = t.getTreeNode(h, k, t.root, cc);
1637	>	val = (p == null) ? v : mf.apply(p.val, v);
1638	>	if (val != null) {
1639	>	if (p != null)
1640	>	p.val = val;
1641	>	else {
1642	>	delta = 1;
1643	>	t.putTreeNode(h, k, val);
1644	>	}
1645	>	}
1646	>	else if (p != null) {
1647	>	delta = -1;
1648	>	t.deleteTreeNode(p);
1649	>	}
1650		}
1651	+	} finally {
1652	+	t.unlockWrite(stamp);
1653	+	}
1654	+	if (len != 0)
1655		break;
1656	+	}
1657	+	else
1658	+	tab = (Node<K,V>[])fk;
1659	+	}
1660	+	else {
1661	+	synchronized (f) {
1662	+	if (tabAt(tab, i) == f) {
1663	+	len = 1;
1664	+	for (Node<K,V> e = f, pred = null;; ++len) {
1665	+	Object ek;
1666	+	if (e.hash == h &&
1667	+	((ek = e.key) == k || k.equals(ek))) {
1668	+	val = mf.apply(e.val, v);
1669	+	if (val != null)
1670	+	e.val = val;
1671	+	else {
1672	+	delta = -1;
1673	+	Node<K,V> en = e.next;
1674	+	if (pred != null)
1675	+	pred.next = en;
1676	+	else
1677	+	setTabAt(tab, i, en);
1678	+	}
1679	+	break;
1680	+	}
1681	+	pred = e;
1682	+	if ((e = e.next) == null) {
1683	+	delta = 1;
1684	+	val = v;
1685	+	pred.next = new Node<K,V>(h, k, val, null);
1686	+	if (len > TREE_THRESHOLD)
1687	+	replaceWithTreeBin(tab, i, k);
1688	+	break;
1689	+	}
1690	+	}
1691		}
548	–	pred = e;
549	–	e = next;
1692		}
1693	<	} finally {
1694	<	unlock();
1693	>	if (len != 0)
1694	>	break;
1695		}
554	–	return oldValue;
1696		}
1697	+	if (delta != 0)
1698	+	addCount((long)delta, len);
1699	+	return val;
1700	+	}
1701	+
1702	+	/** Implementation for putAll */
1703	+	private final void internalPutAll(Map<? extends K, ? extends V> m) {
1704	+	tryPresize(m.size());
1705	+	long delta = 0L;     // number of uncommitted additions
1706	+	boolean npe = false; // to throw exception on exit for nulls
1707	+	try {                // to clean up counts on other exceptions
1708	+	for (Map.Entry<?, ? extends V> entry : m.entrySet()) {
1709	+	Object k; V v;
1710	+	if (entry == null || (k = entry.getKey()) == null ||
1711	+	(v = entry.getValue()) == null) {
1712	+	npe = true;
1713	+	break;
1714	+	}
1715	+	int h = spread(k.hashCode());
1716	+	for (Node<K,V>[] tab = table;;) {
1717	+	int i; Node<K,V> f; int fh; Object fk;
1718	+	if (tab == null)
1719	+	tab = initTable();
1720	+	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1721	+	if (casTabAt(tab, i, null, new Node<K,V>(h, k, v, null))) {
1722	+	++delta;
1723	+	break;
1724	+	}
1725	+	}
1726	+	else if ((fh = f.hash) < 0) {
1727	+	if ((fk = f.key) instanceof TreeBin) {
1728	+	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1729	+	long stamp = t.writeLock();
1730	+	boolean validated = false;
1731	+	try {
1732	+	if (tabAt(tab, i) == f) {
1733	+	validated = true;
1734	+	Class<?> cc = comparableClassFor(k.getClass());
1735	+	TreeNode<K,V> p = t.getTreeNode(h, k,
1736	+	t.root, cc);
1737	+	if (p != null)
1738	+	p.val = v;
1739	+	else {
1740	+	++delta;
1741	+	t.putTreeNode(h, k, v);
1742	+	}
1743	+	}
1744	+	} finally {
1745	+	t.unlockWrite(stamp);
1746	+	}
1747	+	if (validated)
1748	+	break;
1749	+	}
1750	+	else
1751	+	tab = (Node<K,V>[])fk;
1752	+	}
1753	+	else {
1754	+	int len = 0;
1755	+	synchronized (f) {
1756	+	if (tabAt(tab, i) == f) {
1757	+	len = 1;
1758	+	for (Node<K,V> e = f;; ++len) {
1759	+	Object ek;
1760	+	if (e.hash == h &&
1761	+	((ek = e.key) == k || k.equals(ek))) {
1762	+	e.val = v;
1763	+	break;
1764	+	}
1765	+	Node<K,V> last = e;
1766	+	if ((e = e.next) == null) {
1767	+	++delta;
1768	+	last.next = new Node<K,V>(h, k, v, null);
1769	+	if (len > TREE_THRESHOLD)
1770	+	replaceWithTreeBin(tab, i, k);
1771	+	break;
1772	+	}
1773	+	}
1774	+	}
1775	+	}
1776	+	if (len != 0) {
1777	+	if (len > 1) {
1778	+	addCount(delta, len);
1779	+	delta = 0L;
1780	+	}
1781	+	break;
1782	+	}
1783	+	}
1784	+	}
1785	+	}
1786	+	} finally {
1787	+	if (delta != 0L)
1788	+	addCount(delta, 2);
1789	+	}
1790	+	if (npe)
1791	+	throw new NullPointerException();
1792	+	}
1793
1794	<	final boolean replace(K key, int hash, V oldValue, V newValue) {
1795	<	if (!tryLock())
1796	<	scanAndLock(key, hash);
1797	<	boolean replaced = false;
1798	<	try {
1799	<	HashEntry<K,V> e;
1800	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1801	<	K k;
1802	<	if ((k = e.key) == key ||
1803	<	(e.hash == hash && key.equals(k))) {
1804	<	if (oldValue.equals(e.value)) {
1805	<	e.value = newValue;
1806	<	++modCount;
1807	<	replaced = true;
1794	>	/**
1795	>	* Implementation for clear. Steps through each bin, removing all
1796	>	* nodes.
1797	>	*/
1798	>	private final void internalClear() {
1799	>	long delta = 0L; // negative number of deletions
1800	>	int i = 0;
1801	>	Node<K,V>[] tab = table;
1802	>	while (tab != null && i < tab.length) {
1803	>	Node<K,V> f = tabAt(tab, i);
1804	>	if (f == null)
1805	>	++i;
1806	>	else if (f.hash < 0) {
1807	>	Object fk;
1808	>	if ((fk = f.key) instanceof TreeBin) {
1809	>	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1810	>	long stamp = t.writeLock();
1811	>	try {
1812	>	if (tabAt(tab, i) == f) {
1813	>	for (Node<K,V> p = t.first; p != null; p = p.next)
1814	>	--delta;
1815	>	t.first = null;
1816	>	t.root = null;
1817	>	++i;
1818		}
1819	<	break;
1819	>	} finally {
1820	>	t.unlockWrite(stamp);
1821	>	}
1822	>	}
1823	>	else
1824	>	tab = (Node<K,V>[])fk;
1825	>	}
1826	>	else {
1827	>	synchronized (f) {
1828	>	if (tabAt(tab, i) == f) {
1829	>	for (Node<K,V> e = f; e != null; e = e.next)
1830	>	--delta;
1831	>	setTabAt(tab, i, null);
1832	>	++i;
1833		}
1834		}
575	–	} finally {
576	–	unlock();
1835		}
578	–	return replaced;
1836		}
1837	+	if (delta != 0L)
1838	+	addCount(delta, -1);
1839	+	}
1840
1841	<	final V replace(K key, int hash, V value) {
1842	<	if (!tryLock())
1843	<	scanAndLock(key, hash);
1844	<	V oldValue = null;
1845	<	try {
1846	<	HashEntry<K,V> e;
1847	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1848	<	K k;
1849	<	if ((k = e.key) == key ||
1850	<	(e.hash == hash && key.equals(k))) {
1851	<	oldValue = e.value;
1852	<	e.value = value;
1853	<	++modCount;
1841	>	/* ---------------- Table Initialization and Resizing -------------- */
1842	>
1843	>	/**
1844	>	* Returns a power of two table size for the given desired capacity.
1845	>	* See Hackers Delight, sec 3.2
1846	>	*/
1847	>	private static final int tableSizeFor(int c) {
1848	>	int n = c - 1;
1849	>	n |= n >>> 1;
1850	>	n |= n >>> 2;
1851	>	n |= n >>> 4;
1852	>	n |= n >>> 8;
1853	>	n |= n >>> 16;
1854	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1855	>	}
1856	>
1857	>	/**
1858	>	* Initializes table, using the size recorded in sizeCtl.
1859	>	*/
1860	>	private final Node<K,V>[] initTable() {
1861	>	Node<K,V>[] tab; int sc;
1862	>	while ((tab = table) == null) {
1863	>	if ((sc = sizeCtl) < 0)
1864	>	Thread.yield(); // lost initialization race; just spin
1865	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1866	>	try {
1867	>	if ((tab = table) == null) {
1868	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1869	>	table = tab = (Node<K,V>[])new Node[n];
1870	>	sc = n - (n >>> 2);
1871	>	}
1872	>	} finally {
1873	>	sizeCtl = sc;
1874	>	}
1875	>	break;
1876	>	}
1877	>	}
1878	>	return tab;
1879	>	}
1880	>
1881	>	/**
1882	>	* Adds to count, and if table is too small and not already
1883	>	* resizing, initiates transfer. If already resizing, helps
1884	>	* perform transfer if work is available.  Rechecks occupancy
1885	>	* after a transfer to see if another resize is already needed
1886	>	* because resizings are lagging additions.
1887	>	*
1888	>	* @param x the count to add
1889	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
1890	>	*/
1891	>	private final void addCount(long x, int check) {
1892	>	Cell[] as; long b, s;
1893	>	if ((as = counterCells) != null ||
1894	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
1895	>	Cell a; long v; int m;
1896	>	boolean uncontended = true;
1897	>	if (as == null || (m = as.length - 1) < 0 ||
1898	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
1899	>	!(uncontended =
1900	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
1901	>	fullAddCount(x, uncontended);
1902	>	return;
1903	>	}
1904	>	if (check <= 1)
1905	>	return;
1906	>	s = sumCount();
1907	>	}
1908	>	if (check >= 0) {
1909	>	Node<K,V>[] tab, nt; int sc;
1910	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
1911	>	tab.length < MAXIMUM_CAPACITY) {
1912	>	if (sc < 0) {
1913	>	if (sc == -1 || transferIndex <= transferOrigin ||
1914	>	(nt = nextTable) == null)
1915		break;
1916	+	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
1917	+	transfer(tab, nt);
1918	+	}
1919	+	else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
1920	+	transfer(tab, null);
1921	+	s = sumCount();
1922	+	}
1923	+	}
1924	+	}
1925	+
1926	+	/**
1927	+	* Tries to presize table to accommodate the given number of elements.
1928	+	*
1929	+	* @param size number of elements (doesn't need to be perfectly accurate)
1930	+	*/
1931	+	private final void tryPresize(int size) {
1932	+	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1933	+	tableSizeFor(size + (size >>> 1) + 1);
1934	+	int sc;
1935	+	while ((sc = sizeCtl) >= 0) {
1936	+	Node<K,V>[] tab = table; int n;
1937	+	if (tab == null || (n = tab.length) == 0) {
1938	+	n = (sc > c) ? sc : c;
1939	+	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1940	+	try {
1941	+	if (table == tab) {
1942	+	table = (Node<K,V>[])new Node[n];
1943	+	sc = n - (n >>> 2);
1944	+	}
1945	+	} finally {
1946	+	sizeCtl = sc;
1947		}
1948		}
597	–	} finally {
598	–	unlock();
1949		}
1950	<	return oldValue;
1950	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1951	>	break;
1952	>	else if (tab == table &&
1953	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
1954	>	transfer(tab, null);
1955		}
1956	+	}
1957
1958	<	final void clear() {
1959	<	lock();
1958	>	/**
1959	>	* Moves and/or copies the nodes in each bin to new table. See
1960	>	* above for explanation.
1961	>	*/
1962	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
1963	>	int n = tab.length, stride;
1964	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
1965	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
1966	>	if (nextTab == null) {            // initiating
1967		try {
1968	<	HashEntry<K,V>[] tab = table;
1969	<	for (int i = 0; i < tab.length ; i++)
1970	<	setEntryAt(tab, i, null);
1971	<	++modCount;
1972	<	count = 0;
1973	<	} finally {
1974	<	unlock();
1968	>	nextTab = (Node<K,V>[])new Node[n << 1];
1969	>	} catch (Throwable ex) {      // try to cope with OOME
1970	>	sizeCtl = Integer.MAX_VALUE;
1971	>	return;
1972	>	}
1973	>	nextTable = nextTab;
1974	>	transferOrigin = n;
1975	>	transferIndex = n;
1976	>	Node<K,V> rev = new Node<K,V>(MOVED, tab, null, null);
1977	>	for (int k = n; k > 0;) {    // progressively reveal ready slots
1978	>	int nextk = (k > stride) ? k - stride : 0;
1979	>	for (int m = nextk; m < k; ++m)
1980	>	nextTab[m] = rev;
1981	>	for (int m = n + nextk; m < n + k; ++m)
1982	>	nextTab[m] = rev;
1983	>	U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
1984	>	}
1985	>	}
1986	>	int nextn = nextTab.length;
1987	>	Node<K,V> fwd = new Node<K,V>(MOVED, nextTab, null, null);
1988	>	boolean advance = true;
1989	>	for (int i = 0, bound = 0;;) {
1990	>	int nextIndex, nextBound; Node<K,V> f; Object fk;
1991	>	while (advance) {
1992	>	if (--i >= bound)
1993	>	advance = false;
1994	>	else if ((nextIndex = transferIndex) <= transferOrigin) {
1995	>	i = -1;
1996	>	advance = false;
1997	>	}
1998	>	else if (U.compareAndSwapInt
1999	>	(this, TRANSFERINDEX, nextIndex,
2000	>	nextBound = (nextIndex > stride ?
2001	>	nextIndex - stride : 0))) {
2002	>	bound = nextBound;
2003	>	i = nextIndex - 1;
2004	>	advance = false;
2005	>	}
2006	>	}
2007	>	if (i < 0 || i >= n || i + n >= nextn) {
2008	>	for (int sc;;) {
2009	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
2010	>	if (sc == -1) {
2011	>	nextTable = null;
2012	>	table = nextTab;
2013	>	sizeCtl = (n << 1) - (n >>> 1);
2014	>	}
2015	>	return;
2016	>	}
2017	>	}
2018	>	}
2019	>	else if ((f = tabAt(tab, i)) == null) {
2020	>	if (casTabAt(tab, i, null, fwd)) {
2021	>	setTabAt(nextTab, i, null);
2022	>	setTabAt(nextTab, i + n, null);
2023	>	advance = true;
2024	>	}
2025	>	}
2026	>	else if (f.hash >= 0) {
2027	>	synchronized (f) {
2028	>	if (tabAt(tab, i) == f) {
2029	>	int runBit = f.hash & n;
2030	>	Node<K,V> lastRun = f, lo = null, hi = null;
2031	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2032	>	int b = p.hash & n;
2033	>	if (b != runBit) {
2034	>	runBit = b;
2035	>	lastRun = p;
2036	>	}
2037	>	}
2038	>	if (runBit == 0)
2039	>	lo = lastRun;
2040	>	else
2041	>	hi = lastRun;
2042	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2043	>	int ph = p.hash; Object pk = p.key; V pv = p.val;
2044	>	if ((ph & n) == 0)
2045	>	lo = new Node<K,V>(ph, pk, pv, lo);
2046	>	else
2047	>	hi = new Node<K,V>(ph, pk, pv, hi);
2048	>	}
2049	>	setTabAt(nextTab, i, lo);
2050	>	setTabAt(nextTab, i + n, hi);
2051	>	setTabAt(tab, i, fwd);
2052	>	advance = true;
2053	>	}
2054	>	}
2055	>	}
2056	>	else if ((fk = f.key) instanceof TreeBin) {
2057	>	TreeBin<K,V> t = (TreeBin<K,V>)fk;
2058	>	long stamp = t.writeLock();
2059	>	try {
2060	>	if (tabAt(tab, i) == f) {
2061	>	TreeNode<K,V> root;
2062	>	Node<K,V> ln = null, hn = null;
2063	>	if ((root = t.root) != null) {
2064	>	Node<K,V> e, p; TreeNode<K,V> lr, rr; int lh;
2065	>	TreeBin<K,V> lt = null, ht = null;
2066	>	for (lr = root; lr.left != null; lr = lr.left);
2067	>	for (rr = root; rr.right != null; rr = rr.right);
2068	>	if ((lh = lr.hash) == rr.hash) { // move entire tree
2069	>	if ((lh & n) == 0)
2070	>	lt = t;
2071	>	else
2072	>	ht = t;
2073	>	}
2074	>	else {
2075	>	lt = new TreeBin<K,V>();
2076	>	ht = new TreeBin<K,V>();
2077	>	int lc = 0, hc = 0;
2078	>	for (e = t.first; e != null; e = e.next) {
2079	>	int h = e.hash;
2080	>	Object k = e.key; V v = e.val;
2081	>	if ((h & n) == 0) {
2082	>	++lc;
2083	>	lt.putTreeNode(h, k, v);
2084	>	}
2085	>	else {
2086	>	++hc;
2087	>	ht.putTreeNode(h, k, v);
2088	>	}
2089	>	}
2090	>	if (lc < TREE_THRESHOLD) { // throw away
2091	>	for (p = lt.first; p != null; p = p.next)
2092	>	ln = new Node<K,V>(p.hash, p.key,
2093	>	p.val, ln);
2094	>	lt = null;
2095	>	}
2096	>	if (hc < TREE_THRESHOLD) {
2097	>	for (p = ht.first; p != null; p = p.next)
2098	>	hn = new Node<K,V>(p.hash, p.key,
2099	>	p.val, hn);
2100	>	ht = null;
2101	>	}
2102	>	}
2103	>	if (ln == null && lt != null)
2104	>	ln = new Node<K,V>(MOVED, lt, null, null);
2105	>	if (hn == null && ht != null)
2106	>	hn = new Node<K,V>(MOVED, ht, null, null);
2107	>	}
2108	>	setTabAt(nextTab, i, ln);
2109	>	setTabAt(nextTab, i + n, hn);
2110	>	setTabAt(tab, i, fwd);
2111	>	advance = true;
2112	>	}
2113	>	} finally {
2114	>	t.unlockWrite(stamp);
2115	>	}
2116		}
2117	+	else
2118	+	advance = true; // already processed
2119		}
2120		}
2121
2122	<	// Accessing segments
2123	<
2124	<	/**
2125	<	* Gets the jth element of given segment array (if nonnull) with
2126	<	* volatile element access semantics via Unsafe. (The null check
2127	<	* can trigger harmlessly only during deserialization.) Note:
2128	<	* because each element of segments array is set only once (using
2129	<	* fully ordered writes), some performance-sensitive methods rely
2130	<	* on this method only as a recheck upon null reads.
2131	<	*/
2132	<	@SuppressWarnings("unchecked")
2133	<	static final <K,V> Segment<K,V> segmentAt(Segment<K,V>[] ss, int j) {
629	<	long u = (j << SSHIFT) + SBASE;
630	<	return ss == null ? null :
631	<	(Segment<K,V>) UNSAFE.getObjectVolatile(ss, u);
2122	>	/* ---------------- Counter support -------------- */
2123	>
2124	>	final long sumCount() {
2125	>	Cell[] as = counterCells; Cell a;
2126	>	long sum = baseCount;
2127	>	if (as != null) {
2128	>	for (int i = 0; i < as.length; ++i) {
2129	>	if ((a = as[i]) != null)
2130	>	sum += a.value;
2131	>	}
2132	>	}
2133	>	return sum;
2134		}
2135
2136	<	/**
2137	<	* Returns the segment for the given index, creating it and
2138	<	* recording in segment table (via CAS) if not already present.
2139	<	*
2140	<	* @param k the index
2141	<	* @return the segment
2142	<	*/
2143	<	@SuppressWarnings("unchecked")
2144	<	private Segment<K,V> ensureSegment(int k) {
2145	<	final Segment<K,V>[] ss = this.segments;
2146	<	long u = (k << SSHIFT) + SBASE; // raw offset
2147	<	Segment<K,V> seg;
2148	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u)) == null) {
2149	<	Segment<K,V> proto = ss[0]; // use segment 0 as prototype
2150	<	int cap = proto.table.length;
2151	<	float lf = proto.loadFactor;
2152	<	int threshold = (int)(cap * lf);
2153	<	HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry[cap];
2154	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
2155	<	== null) { // recheck
2156	<	Segment<K,V> s = new Segment<K,V>(lf, threshold, tab);
2157	<	while ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
2158	<	== null) {
2159	<	if (UNSAFE.compareAndSwapObject(ss, u, null, seg = s))
2160	<	break;
2136	>	// See LongAdder version for explanation
2137	>	private final void fullAddCount(long x, boolean wasUncontended) {
2138	>	int h;
2139	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2140	>	ThreadLocalRandom.localInit();      // force initialization
2141	>	h = ThreadLocalRandom.getProbe();
2142	>	wasUncontended = true;
2143	>	}
2144	>	boolean collide = false;                // True if last slot nonempty
2145	>	for (;;) {
2146	>	Cell[] as; Cell a; int n; long v;
2147	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2148	>	if ((a = as[(n - 1) & h]) == null) {
2149	>	if (cellsBusy == 0) {            // Try to attach new Cell
2150	>	Cell r = new Cell(x); // Optimistic create
2151	>	if (cellsBusy == 0 &&
2152	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2153	>	boolean created = false;
2154	>	try {               // Recheck under lock
2155	>	Cell[] rs; int m, j;
2156	>	if ((rs = counterCells) != null &&
2157	>	(m = rs.length) > 0 &&
2158	>	rs[j = (m - 1) & h] == null) {
2159	>	rs[j] = r;
2160	>	created = true;
2161	>	}
2162	>	} finally {
2163	>	cellsBusy = 0;
2164	>	}
2165	>	if (created)
2166	>	break;
2167	>	continue;           // Slot is now non-empty
2168	>	}
2169	>	}
2170	>	collide = false;
2171	>	}
2172	>	else if (!wasUncontended)       // CAS already known to fail
2173	>	wasUncontended = true;      // Continue after rehash
2174	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2175	>	break;
2176	>	else if (counterCells != as || n >= NCPU)
2177	>	collide = false;            // At max size or stale
2178	>	else if (!collide)
2179	>	collide = true;
2180	>	else if (cellsBusy == 0 &&
2181	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2182	>	try {
2183	>	if (counterCells == as) {// Expand table unless stale
2184	>	Cell[] rs = new Cell[n << 1];
2185	>	for (int i = 0; i < n; ++i)
2186	>	rs[i] = as[i];
2187	>	counterCells = rs;
2188	>	}
2189	>	} finally {
2190	>	cellsBusy = 0;
2191	>	}
2192	>	collide = false;
2193	>	continue;                   // Retry with expanded table
2194		}
2195	+	h = ThreadLocalRandom.advanceProbe(h);
2196	+	}
2197	+	else if (cellsBusy == 0 && counterCells == as &&
2198	+	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2199	+	boolean init = false;
2200	+	try {                           // Initialize table
2201	+	if (counterCells == as) {
2202	+	Cell[] rs = new Cell[2];
2203	+	rs[h & 1] = new Cell(x);
2204	+	counterCells = rs;
2205	+	init = true;
2206	+	}
2207	+	} finally {
2208	+	cellsBusy = 0;
2209	+	}
2210	+	if (init)
2211	+	break;
2212		}
2213	+	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2214	+	break;                          // Fall back on using base
2215		}
662	–	return seg;
2216		}
2217
2218	<	// Hash-based segment and entry accesses
2218	>	/* ----------------Table Traversal -------------- */
2219
2220		/**
2221	<	* Gets the segment for the given hash code.
2222	<	*/
2223	<	@SuppressWarnings("unchecked")
2224	<	private Segment<K,V> segmentForHash(int h) {
2225	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
2226	<	return (Segment<K,V>) UNSAFE.getObjectVolatile(segments, u);
2221	>	* Encapsulates traversal for methods such as containsValue; also
2222	>	* serves as a base class for other iterators and spliterators.
2223	>	*
2224	>	* Method advance visits once each still-valid node that was
2225	>	* reachable upon iterator construction. It might miss some that
2226	>	* were added to a bin after the bin was visited, which is OK wrt
2227	>	* consistency guarantees. Maintaining this property in the face
2228	>	* of possible ongoing resizes requires a fair amount of
2229	>	* bookkeeping state that is difficult to optimize away amidst
2230	>	* volatile accesses.  Even so, traversal maintains reasonable
2231	>	* throughput.
2232	>	*
2233	>	* Normally, iteration proceeds bin-by-bin traversing lists.
2234	>	* However, if the table has been resized, then all future steps
2235	>	* must traverse both the bin at the current index as well as at
2236	>	* (index + baseSize); and so on for further resizings. To
2237	>	* paranoically cope with potential sharing by users of iterators
2238	>	* across threads, iteration terminates if a bounds checks fails
2239	>	* for a table read.
2240	>	*/
2241	>	static class Traverser<K,V> {
2242	>	Node<K,V>[] tab;        // current table; updated if resized
2243	>	Node<K,V> next;         // the next entry to use
2244	>	int index;              // index of bin to use next
2245	>	int baseIndex;          // current index of initial table
2246	>	int baseLimit;          // index bound for initial table
2247	>	final int baseSize;     // initial table size
2248	>
2249	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
2250	>	this.tab = tab;
2251	>	this.baseSize = size;
2252	>	this.baseIndex = this.index = index;
2253	>	this.baseLimit = limit;
2254	>	this.next = null;
2255	>	}
2256	>
2257	>	/**
2258	>	* Advances if possible, returning next valid node, or null if none.
2259	>	*/
2260	>	final Node<K,V> advance() {
2261	>	Node<K,V> e;
2262	>	if ((e = next) != null)
2263	>	e = e.next;
2264	>	for (;;) {
2265	>	Node<K,V>[] t; int i, n; Object ek;  // must use locals in checks
2266	>	if (e != null)
2267	>	return next = e;
2268	>	if (baseIndex >= baseLimit || (t = tab) == null ||
2269	>	(n = t.length) <= (i = index) || i < 0)
2270	>	return next = null;
2271	>	if ((e = tabAt(t, index)) != null && e.hash < 0) {
2272	>	if ((ek = e.key) instanceof TreeBin)
2273	>	e = ((TreeBin<K,V>)ek).first;
2274	>	else {
2275	>	tab = (Node<K,V>[])ek;
2276	>	e = null;
2277	>	continue;
2278	>	}
2279	>	}
2280	>	if ((index += baseSize) >= n)
2281	>	index = ++baseIndex;    // visit upper slots if present
2282	>	}
2283	>	}
2284		}
2285
2286		/**
2287	<	* Gets the table entry for the given segment and hash code.
2287	>	* Base of key, value, and entry Iterators. Adds fields to
2288	>	* Traverser to support iterator.remove
2289		*/
2290	<	@SuppressWarnings("unchecked")
2291	<	static final <K,V> HashEntry<K,V> entryForHash(Segment<K,V> seg, int h) {
2292	<	HashEntry<K,V>[] tab;
2293	<	return (seg == null || (tab = seg.table) == null) ? null :
2294	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
2295	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
2290	>	static class BaseIterator<K,V> extends Traverser<K,V> {
2291	>	final ConcurrentHashMap<K,V> map;
2292	>	Node<K,V> lastReturned;
2293	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
2294	>	ConcurrentHashMap<K,V> map) {
2295	>	super(tab, size, index, limit);
2296	>	this.map = map;
2297	>	advance();
2298	>	}
2299	>
2300	>	public final boolean hasNext() { return next != null; }
2301	>	public final boolean hasMoreElements() { return next != null; }
2302	>
2303	>	public final void remove() {
2304	>	Node<K,V> p;
2305	>	if ((p = lastReturned) == null)
2306	>	throw new IllegalStateException();
2307	>	lastReturned = null;
2308	>	map.internalReplace((K)p.key, null, null);
2309	>	}
2310	>	}
2311	>
2312	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
2313	>	implements Iterator<K>, Enumeration<K> {
2314	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
2315	>	ConcurrentHashMap<K,V> map) {
2316	>	super(tab, index, size, limit, map);
2317	>	}
2318	>
2319	>	public final K next() {
2320	>	Node<K,V> p;
2321	>	if ((p = next) == null)
2322	>	throw new NoSuchElementException();
2323	>	K k = (K)p.key;
2324	>	lastReturned = p;
2325	>	advance();
2326	>	return k;
2327	>	}
2328	>
2329	>	public final K nextElement() { return next(); }
2330	>	}
2331	>
2332	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
2333	>	implements Iterator<V>, Enumeration<V> {
2334	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
2335	>	ConcurrentHashMap<K,V> map) {
2336	>	super(tab, index, size, limit, map);
2337	>	}
2338	>
2339	>	public final V next() {
2340	>	Node<K,V> p;
2341	>	if ((p = next) == null)
2342	>	throw new NoSuchElementException();
2343	>	V v = p.val;
2344	>	lastReturned = p;
2345	>	advance();
2346	>	return v;
2347	>	}
2348	>
2349	>	public final V nextElement() { return next(); }
2350		}
2351
2352	+	static final class EntryIterator<K,V> extends BaseIterator<K,V>
2353	+	implements Iterator<Map.Entry<K,V>> {
2354	+	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
2355	+	ConcurrentHashMap<K,V> map) {
2356	+	super(tab, index, size, limit, map);
2357	+	}
2358	+
2359	+	public final Map.Entry<K,V> next() {
2360	+	Node<K,V> p;
2361	+	if ((p = next) == null)
2362	+	throw new NoSuchElementException();
2363	+	K k = (K)p.key;
2364	+	V v = p.val;
2365	+	lastReturned = p;
2366	+	advance();
2367	+	return new MapEntry<K,V>(k, v, map);
2368	+	}
2369	+	}
2370	+
2371	+	static final class KeySpliterator<K,V> extends Traverser<K,V>
2372	+	implements Spliterator<K> {
2373	+	long est;               // size estimate
2374	+	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
2375	+	long est) {
2376	+	super(tab, size, index, limit);
2377	+	this.est = est;
2378	+	}
2379	+
2380	+	public Spliterator<K> trySplit() {
2381	+	int i, f, h;
2382	+	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
2383	+	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
2384	+	f, est >>>= 1);
2385	+	}
2386	+
2387	+	public void forEachRemaining(Consumer<? super K> action) {
2388	+	if (action == null) throw new NullPointerException();
2389	+	for (Node<K,V> p; (p = advance()) != null;)
2390	+	action.accept((K)p.key);
2391	+	}
2392	+
2393	+	public boolean tryAdvance(Consumer<? super K> action) {
2394	+	if (action == null) throw new NullPointerException();
2395	+	Node<K,V> p;
2396	+	if ((p = advance()) == null)
2397	+	return false;
2398	+	action.accept((K)p.key);
2399	+	return true;
2400	+	}
2401	+
2402	+	public long estimateSize() { return est; }
2403	+
2404	+	public int characteristics() {
2405	+	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
2406	+	Spliterator.NONNULL;
2407	+	}
2408	+	}
2409	+
2410	+	static final class ValueSpliterator<K,V> extends Traverser<K,V>
2411	+	implements Spliterator<V> {
2412	+	long est;               // size estimate
2413	+	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
2414	+	long est) {
2415	+	super(tab, size, index, limit);
2416	+	this.est = est;
2417	+	}
2418	+
2419	+	public Spliterator<V> trySplit() {
2420	+	int i, f, h;
2421	+	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
2422	+	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
2423	+	f, est >>>= 1);
2424	+	}
2425	+
2426	+	public void forEachRemaining(Consumer<? super V> action) {
2427	+	if (action == null) throw new NullPointerException();
2428	+	for (Node<K,V> p; (p = advance()) != null;)
2429	+	action.accept(p.val);
2430	+	}
2431	+
2432	+	public boolean tryAdvance(Consumer<? super V> action) {
2433	+	if (action == null) throw new NullPointerException();
2434	+	Node<K,V> p;
2435	+	if ((p = advance()) == null)
2436	+	return false;
2437	+	action.accept(p.val);
2438	+	return true;
2439	+	}
2440	+
2441	+	public long estimateSize() { return est; }
2442	+
2443	+	public int characteristics() {
2444	+	return Spliterator.CONCURRENT | Spliterator.NONNULL;
2445	+	}
2446	+	}
2447	+
2448	+	static final class EntrySpliterator<K,V> extends Traverser<K,V>
2449	+	implements Spliterator<Map.Entry<K,V>> {
2450	+	final ConcurrentHashMap<K,V> map; // To export MapEntry
2451	+	long est;               // size estimate
2452	+	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
2453	+	long est, ConcurrentHashMap<K,V> map) {
2454	+	super(tab, size, index, limit);
2455	+	this.map = map;
2456	+	this.est = est;
2457	+	}
2458	+
2459	+	public Spliterator<Map.Entry<K,V>> trySplit() {
2460	+	int i, f, h;
2461	+	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
2462	+	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
2463	+	f, est >>>= 1, map);
2464	+	}
2465	+
2466	+	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
2467	+	if (action == null) throw new NullPointerException();
2468	+	for (Node<K,V> p; (p = advance()) != null; )
2469	+	action.accept(new MapEntry<K,V>((K)p.key, p.val, map));
2470	+	}
2471	+
2472	+	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
2473	+	if (action == null) throw new NullPointerException();
2474	+	Node<K,V> p;
2475	+	if ((p = advance()) == null)
2476	+	return false;
2477	+	action.accept(new MapEntry<K,V>((K)p.key, p.val, map));
2478	+	return true;
2479	+	}
2480	+
2481	+	public long estimateSize() { return est; }
2482	+
2483	+	public int characteristics() {
2484	+	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
2485	+	Spliterator.NONNULL;
2486	+	}
2487	+	}
2488	+
2489	+
2490		/* ---------------- Public operations -------------- */
2491
2492		/**
2493	<	* Creates a new, empty map with the specified initial
691	<	* capacity, load factor and concurrency level.
692	<	*
693	<	* @param initialCapacity the initial capacity. The implementation
694	<	* performs internal sizing to accommodate this many elements.
695	<	* @param loadFactor  the load factor threshold, used to control resizing.
696	<	* Resizing may be performed when the average number of elements per
697	<	* bin exceeds this threshold.
698	<	* @param concurrencyLevel the estimated number of concurrently
699	<	* updating threads. The implementation performs internal sizing
700	<	* to try to accommodate this many threads.
701	<	* @throws IllegalArgumentException if the initial capacity is
702	<	* negative or the load factor or concurrencyLevel are
703	<	* nonpositive.
2493	>	* Creates a new, empty map with the default initial table size (16).
2494		*/
2495	<	@SuppressWarnings("unchecked")
706	<	public ConcurrentHashMap(int initialCapacity,
707	<	float loadFactor, int concurrencyLevel) {
708	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
709	<	throw new IllegalArgumentException();
710	<	if (concurrencyLevel > MAX_SEGMENTS)
711	<	concurrencyLevel = MAX_SEGMENTS;
712	<	// Find power-of-two sizes best matching arguments
713	<	int sshift = 0;
714	<	int ssize = 1;
715	<	while (ssize < concurrencyLevel) {
716	<	++sshift;
717	<	ssize <<= 1;
718	<	}
719	<	this.segmentShift = 32 - sshift;
720	<	this.segmentMask = ssize - 1;
721	<	if (initialCapacity > MAXIMUM_CAPACITY)
722	<	initialCapacity = MAXIMUM_CAPACITY;
723	<	int c = initialCapacity / ssize;
724	<	if (c * ssize < initialCapacity)
725	<	++c;
726	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
727	<	while (cap < c)
728	<	cap <<= 1;
729	<	// create segments and segments[0]
730	<	Segment<K,V> s0 =
731	<	new Segment<K,V>(loadFactor, (int)(cap * loadFactor),
732	<	(HashEntry<K,V>[])new HashEntry[cap]);
733	<	Segment<K,V>[] ss = (Segment<K,V>[])new Segment[ssize];
734	<	UNSAFE.putOrderedObject(ss, SBASE, s0); // ordered write of segments[0]
735	<	this.segments = ss;
2495	>	public ConcurrentHashMap() {
2496		}
2497
2498		/**
2499	<	* Creates a new, empty map with the specified initial capacity
2500	<	* and load factor and with the default concurrencyLevel (16).
2499	>	* Creates a new, empty map with an initial table size
2500	>	* accommodating the specified number of elements without the need
2501	>	* to dynamically resize.
2502		*
2503		* @param initialCapacity The implementation performs internal
2504		* sizing to accommodate this many elements.
744	–	* @param loadFactor  the load factor threshold, used to control resizing.
745	–	* Resizing may be performed when the average number of elements per
746	–	* bin exceeds this threshold.
2505		* @throws IllegalArgumentException if the initial capacity of
2506	<	* elements is negative or the load factor is nonpositive
2506	>	* elements is negative
2507	>	*/
2508	>	public ConcurrentHashMap(int initialCapacity) {
2509	>	if (initialCapacity < 0)
2510	>	throw new IllegalArgumentException();
2511	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2512	>	MAXIMUM_CAPACITY :
2513	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2514	>	this.sizeCtl = cap;
2515	>	}
2516	>
2517	>	/**
2518	>	* Creates a new map with the same mappings as the given map.
2519		*
2520	<	* @since 1.6
2520	>	* @param m the map
2521		*/
2522	<	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
2523	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2522	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2523	>	this.sizeCtl = DEFAULT_CAPACITY;
2524	>	internalPutAll(m);
2525		}
2526
2527		/**
2528	<	* Creates a new, empty map with the specified initial capacity,
2529	<	* and with default load factor (0.75) and concurrencyLevel (16).
2528	>	* Creates a new, empty map with an initial table size based on
2529	>	* the given number of elements ({@code initialCapacity}) and
2530	>	* initial table density ({@code loadFactor}).
2531		*
2532		* @param initialCapacity the initial capacity. The implementation
2533	<	* performs internal sizing to accommodate this many elements.
2533	>	* performs internal sizing to accommodate this many elements,
2534	>	* given the specified load factor.
2535	>	* @param loadFactor the load factor (table density) for
2536	>	* establishing the initial table size
2537		* @throws IllegalArgumentException if the initial capacity of
2538	<	* elements is negative.
2538	>	* elements is negative or the load factor is nonpositive
2539	>	*
2540	>	* @since 1.6
2541		*/
2542	<	public ConcurrentHashMap(int initialCapacity) {
2543	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2542	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
2543	>	this(initialCapacity, loadFactor, 1);
2544		}
2545
2546		/**
2547	<	* Creates a new, empty map with a default initial capacity (16),
2548	<	* load factor (0.75) and concurrencyLevel (16).
2547	>	* Creates a new, empty map with an initial table size based on
2548	>	* the given number of elements ({@code initialCapacity}), table
2549	>	* density ({@code loadFactor}), and number of concurrently
2550	>	* updating threads ({@code concurrencyLevel}).
2551	>	*
2552	>	* @param initialCapacity the initial capacity. The implementation
2553	>	* performs internal sizing to accommodate this many elements,
2554	>	* given the specified load factor.
2555	>	* @param loadFactor the load factor (table density) for
2556	>	* establishing the initial table size
2557	>	* @param concurrencyLevel the estimated number of concurrently
2558	>	* updating threads. The implementation may use this value as
2559	>	* a sizing hint.
2560	>	* @throws IllegalArgumentException if the initial capacity is
2561	>	* negative or the load factor or concurrencyLevel are
2562	>	* nonpositive
2563		*/
2564	<	public ConcurrentHashMap() {
2565	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2564	>	public ConcurrentHashMap(int initialCapacity,
2565	>	float loadFactor, int concurrencyLevel) {
2566	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2567	>	throw new IllegalArgumentException();
2568	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2569	>	initialCapacity = concurrencyLevel;   // as estimated threads
2570	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2571	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
2572	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
2573	>	this.sizeCtl = cap;
2574		}
2575
2576		/**
2577	<	* Creates a new map with the same mappings as the given map.
2578	<	* The map is created with a capacity of 1.5 times the number
780	<	* of mappings in the given map or 16 (whichever is greater),
781	<	* and a default load factor (0.75) and concurrencyLevel (16).
2577	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2578	>	* from the given type to {@code Boolean.TRUE}.
2579		*
2580	<	* @param m the map
2580	>	* @return the new set
2581	>	* @since 1.8
2582		*/
2583	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2584	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
2585	<	DEFAULT_INITIAL_CAPACITY),
788	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
789	<	putAll(m);
2583	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2584	>	return new KeySetView<K,Boolean>
2585	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2586		}
2587
2588		/**
2589	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
2589	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2590	>	* from the given type to {@code Boolean.TRUE}.
2591		*
2592	<	* @return <tt>true</tt> if this map contains no key-value mappings
2592	>	* @param initialCapacity The implementation performs internal
2593	>	* sizing to accommodate this many elements.
2594	>	* @throws IllegalArgumentException if the initial capacity of
2595	>	* elements is negative
2596	>	* @return the new set
2597	>	* @since 1.8
2598	>	*/
2599	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2600	>	return new KeySetView<K,Boolean>
2601	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2602	>	}
2603	>
2604	>	/**
2605	>	* {@inheritDoc}
2606		*/
2607		public boolean isEmpty() {
2608	<	/*
799	<	* Sum per-segment modCounts to avoid mis-reporting when
800	<	* elements are concurrently added and removed in one segment
801	<	* while checking another, in which case the table was never
802	<	* actually empty at any point. (The sum ensures accuracy up
803	<	* through at least 1<<31 per-segment modifications before
804	<	* recheck.)  Methods size() and containsValue() use similar
805	<	* constructions for stability checks.
806	<	*/
807	<	long sum = 0L;
808	<	final Segment<K,V>[] segments = this.segments;
809	<	for (int j = 0; j < segments.length; ++j) {
810	<	Segment<K,V> seg = segmentAt(segments, j);
811	<	if (seg != null) {
812	<	if (seg.count != 0)
813	<	return false;
814	<	sum += seg.modCount;
815	<	}
816	<	}
817	<	if (sum != 0L) { // recheck unless no modifications
818	<	for (int j = 0; j < segments.length; ++j) {
819	<	Segment<K,V> seg = segmentAt(segments, j);
820	<	if (seg != null) {
821	<	if (seg.count != 0)
822	<	return false;
823	<	sum -= seg.modCount;
824	<	}
825	<	}
826	<	if (sum != 0L)
827	<	return false;
828	<	}
829	<	return true;
2608	>	return sumCount() <= 0L; // ignore transient negative values
2609		}
2610
2611		/**
2612	<	* Returns the number of key-value mappings in this map.  If the
834	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
835	<	* <tt>Integer.MAX_VALUE</tt>.
836	<	*
837	<	* @return the number of key-value mappings in this map
2612	>	* {@inheritDoc}
2613		*/
2614		public int size() {
2615	<	// Try a few times to get accurate count. On failure due to
2616	<	// continuous async changes in table, resort to locking.
2617	<	final Segment<K,V>[] segments = this.segments;
2618	<	int size;
2619	<	boolean overflow; // true if size overflows 32 bits
2620	<	long sum;         // sum of modCounts
2621	<	long last = 0L;   // previous sum
2622	<	int retries = -1; // first iteration isn't retry
2623	<	try {
2624	<	for (;;) {
2625	<	if (retries++ == RETRIES_BEFORE_LOCK) {
2626	<	for (int j = 0; j < segments.length; ++j)
2627	<	ensureSegment(j).lock(); // force creation
2628	<	}
2629	<	sum = 0L;
2630	<	size = 0;
2631	<	overflow = false;
2632	<	for (int j = 0; j < segments.length; ++j) {
2633	<	Segment<K,V> seg = segmentAt(segments, j);
859	<	if (seg != null) {
860	<	sum += seg.modCount;
861	<	int c = seg.count;
862	<	if (c < 0 || (size += c) < 0)
863	<	overflow = true;
864	<	}
865	<	}
866	<	if (sum == last)
867	<	break;
868	<	last = sum;
869	<	}
870	<	} finally {
871	<	if (retries > RETRIES_BEFORE_LOCK) {
872	<	for (int j = 0; j < segments.length; ++j)
873	<	segmentAt(segments, j).unlock();
874	<	}
875	<	}
876	<	return overflow ? Integer.MAX_VALUE : size;
2615	>	long n = sumCount();
2616	>	return ((n < 0L) ? 0 :
2617	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2618	>	(int)n);
2619	>	}
2620	>
2621	>	/**
2622	>	* Returns the number of mappings. This method should be used
2623	>	* instead of {@link #size} because a ConcurrentHashMap may
2624	>	* contain more mappings than can be represented as an int. The
2625	>	* value returned is an estimate; the actual count may differ if
2626	>	* there are concurrent insertions or removals.
2627	>	*
2628	>	* @return the number of mappings
2629	>	* @since 1.8
2630	>	*/
2631	>	public long mappingCount() {
2632	>	long n = sumCount();
2633	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2634		}
2635
2636		/**
#	Line 888 | Line 2645 | public class ConcurrentHashMap<K, V> ext
2645		* @throws NullPointerException if the specified key is null
2646		*/
2647		public V get(Object key) {
2648	<	Segment<K,V> s; // manually integrate access methods to reduce overhead
2649	<	HashEntry<K,V>[] tab;
2650	<	int h = hash(key.hashCode());
2651	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
2652	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
2653	<	(tab = s.table) != null) {
2654	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
2655	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
2656	<	e != null; e = e.next) {
2657	<	K k;
2658	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
2659	<	return e.value;
2660	<	}
2661	<	}
2662	<	return null;
2648	>	return internalGet(key);
2649	>	}
2650	>
2651	>	/**
2652	>	* Returns the value to which the specified key is mapped, or the
2653	>	* given default value if this map contains no mapping for the
2654	>	* key.
2655	>	*
2656	>	* @param key the key whose associated value is to be returned
2657	>	* @param defaultValue the value to return if this map contains
2658	>	* no mapping for the given key
2659	>	* @return the mapping for the key, if present; else the default value
2660	>	* @throws NullPointerException if the specified key is null
2661	>	*/
2662	>	public V getOrDefault(Object key, V defaultValue) {
2663	>	V v;
2664	>	return (v = internalGet(key)) == null ? defaultValue : v;
2665		}
2666
2667		/**
2668		* Tests if the specified object is a key in this table.
2669		*
2670	<	* @param  key   possible key
2671	<	* @return <tt>true</tt> if and only if the specified object
2670	>	* @param  key possible key
2671	>	* @return {@code true} if and only if the specified object
2672		*         is a key in this table, as determined by the
2673	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
2673	>	*         {@code equals} method; {@code false} otherwise
2674		* @throws NullPointerException if the specified key is null
2675		*/
917	–	@SuppressWarnings("unchecked")
2676		public boolean containsKey(Object key) {
2677	<	Segment<K,V> s; // same as get() except no need for volatile value read
920	<	HashEntry<K,V>[] tab;
921	<	int h = hash(key.hashCode());
922	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
923	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
924	<	(tab = s.table) != null) {
925	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
926	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
927	<	e != null; e = e.next) {
928	<	K k;
929	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
930	<	return true;
931	<	}
932	<	}
933	<	return false;
2677	>	return internalGet(key) != null;
2678		}
2679
2680		/**
2681	<	* Returns <tt>true</tt> if this map maps one or more keys to the
2682	<	* specified value. Note: This method requires a full internal
2683	<	* traversal of the hash table, and so is much slower than
940	<	* method <tt>containsKey</tt>.
2681	>	* Returns {@code true} if this map maps one or more keys to the
2682	>	* specified value. Note: This method may require a full traversal
2683	>	* of the map, and is much slower than method {@code containsKey}.
2684		*
2685		* @param value value whose presence in this map is to be tested
2686	<	* @return <tt>true</tt> if this map maps one or more keys to the
2686	>	* @return {@code true} if this map maps one or more keys to the
2687		*         specified value
2688		* @throws NullPointerException if the specified value is null
2689		*/
2690		public boolean containsValue(Object value) {
948	–	// Same idea as size()
2691		if (value == null)
2692		throw new NullPointerException();
2693	<	final Segment<K,V>[] segments = this.segments;
2694	<	boolean found = false;
2695	<	long last = 0L;   // previous sum
2696	<	int retries = -1;
2697	<	try {
2698	<	outer: for (;;) {
2699	<	if (retries++ == RETRIES_BEFORE_LOCK) {
958	<	for (int j = 0; j < segments.length; ++j)
959	<	ensureSegment(j).lock(); // force creation
960	<	}
961	<	long sum = 0L;
962	<	for (int j = 0; j < segments.length; ++j) {
963	<	HashEntry<K,V>[] tab;
964	<	Segment<K,V> seg = segmentAt(segments, j);
965	<	if (seg != null && (tab = seg.table) != null) {
966	<	for (int i = 0 ; i < tab.length; i++) {
967	<	HashEntry<K,V> e;
968	<	for (e = entryAt(tab, i); e != null; e = e.next) {
969	<	V v = e.value;
970	<	if (v != null && value.equals(v)) {
971	<	found = true;
972	<	break outer;
973	<	}
974	<	}
975	<	}
976	<	sum += seg.modCount;
977	<	}
978	<	}
979	<	if (retries > 0 && sum == last)
980	<	break;
981	<	last = sum;
982	<	}
983	<	} finally {
984	<	if (retries > RETRIES_BEFORE_LOCK) {
985	<	for (int j = 0; j < segments.length; ++j)
986	<	segmentAt(segments, j).unlock();
2693	>	Node<K,V>[] t;
2694	>	if ((t = table) != null) {
2695	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
2696	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
2697	>	V v;
2698	>	if ((v = p.val) == value || value.equals(v))
2699	>	return true;
2700		}
2701		}
2702	<	return found;
2702	>	return false;
2703		}
2704
2705		/**
2706		* Legacy method testing if some key maps into the specified value
2707		* in this table.  This method is identical in functionality to
2708	<	* {@link #containsValue}, and exists solely to ensure
2708	>	* {@link #containsValue(Object)}, and exists solely to ensure
2709		* full compatibility with class {@link java.util.Hashtable},
2710		* which supported this method prior to introduction of the
2711		* Java Collections framework.
2712		*
2713		* @param  value a value to search for
2714	<	* @return <tt>true</tt> if and only if some key maps to the
2715	<	*         <tt>value</tt> argument in this table as
2716	<	*         determined by the <tt>equals</tt> method;
2717	<	*         <tt>false</tt> otherwise
2714	>	* @return {@code true} if and only if some key maps to the
2715	>	*         {@code value} argument in this table as
2716	>	*         determined by the {@code equals} method;
2717	>	*         {@code false} otherwise
2718		* @throws NullPointerException if the specified value is null
2719		*/
2720	<	public boolean contains(Object value) {
2720	>	@Deprecated public boolean contains(Object value) {
2721		return containsValue(value);
2722		}
2723
#	Line 1012 | Line 2725 | public class ConcurrentHashMap<K, V> ext
2725		* Maps the specified key to the specified value in this table.
2726		* Neither the key nor the value can be null.
2727		*
2728	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
2728	>	* <p>The value can be retrieved by calling the {@code get} method
2729		* with a key that is equal to the original key.
2730		*
2731		* @param key key with which the specified value is to be associated
2732		* @param value value to be associated with the specified key
2733	<	* @return the previous value associated with <tt>key</tt>, or
2734	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2733	>	* @return the previous value associated with {@code key}, or
2734	>	*         {@code null} if there was no mapping for {@code key}
2735		* @throws NullPointerException if the specified key or value is null
2736		*/
1024	–	@SuppressWarnings("unchecked")
2737		public V put(K key, V value) {
2738	<	Segment<K,V> s;
1027	<	if (value == null)
1028	<	throw new NullPointerException();
1029	<	int hash = hash(key.hashCode());
1030	<	int j = (hash >>> segmentShift) & segmentMask;
1031	<	if ((s = (Segment<K,V>)UNSAFE.getObject          // nonvolatile; recheck
1032	<	(segments, (j << SSHIFT) + SBASE)) == null) //  in ensureSegment
1033	<	s = ensureSegment(j);
1034	<	return s.put(key, hash, value, false);
2738	>	return internalPut(key, value, false);
2739		}
2740
2741		/**
2742		* {@inheritDoc}
2743		*
2744		* @return the previous value associated with the specified key,
2745	<	*         or <tt>null</tt> if there was no mapping for the key
2745	>	*         or {@code null} if there was no mapping for the key
2746		* @throws NullPointerException if the specified key or value is null
2747		*/
1044	–	@SuppressWarnings("unchecked")
2748		public V putIfAbsent(K key, V value) {
2749	<	Segment<K,V> s;
1047	<	if (value == null)
1048	<	throw new NullPointerException();
1049	<	int hash = hash(key.hashCode());
1050	<	int j = (hash >>> segmentShift) & segmentMask;
1051	<	if ((s = (Segment<K,V>)UNSAFE.getObject
1052	<	(segments, (j << SSHIFT) + SBASE)) == null)
1053	<	s = ensureSegment(j);
1054	<	return s.put(key, hash, value, true);
2749	>	return internalPut(key, value, true);
2750		}
2751
2752		/**
#	Line 1062 | Line 2757 | public class ConcurrentHashMap<K, V> ext
2757		* @param m mappings to be stored in this map
2758		*/
2759		public void putAll(Map<? extends K, ? extends V> m) {
2760	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
2761	<	put(e.getKey(), e.getValue());
2760	>	internalPutAll(m);
2761	>	}
2762	>
2763	>	/**
2764	>	* If the specified key is not already associated with a value,
2765	>	* attempts to compute its value using the given mapping function
2766	>	* and enters it into this map unless {@code null}.  The entire
2767	>	* method invocation is performed atomically, so the function is
2768	>	* applied at most once per key.  Some attempted update operations
2769	>	* on this map by other threads may be blocked while computation
2770	>	* is in progress, so the computation should be short and simple,
2771	>	* and must not attempt to update any other mappings of this map.
2772	>	*
2773	>	* @param key key with which the specified value is to be associated
2774	>	* @param mappingFunction the function to compute a value
2775	>	* @return the current (existing or computed) value associated with
2776	>	*         the specified key, or null if the computed value is null
2777	>	* @throws NullPointerException if the specified key or mappingFunction
2778	>	*         is null
2779	>	* @throws IllegalStateException if the computation detectably
2780	>	*         attempts a recursive update to this map that would
2781	>	*         otherwise never complete
2782	>	* @throws RuntimeException or Error if the mappingFunction does so,
2783	>	*         in which case the mapping is left unestablished
2784	>	*/
2785	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
2786	>	return internalComputeIfAbsent(key, mappingFunction);
2787	>	}
2788	>
2789	>	/**
2790	>	* If the value for the specified key is present, attempts to
2791	>	* compute a new mapping given the key and its current mapped
2792	>	* value.  The entire method invocation is performed atomically.
2793	>	* Some attempted update operations on this map by other threads
2794	>	* may be blocked while computation is in progress, so the
2795	>	* computation should be short and simple, and must not attempt to
2796	>	* update any other mappings of this map.
2797	>	*
2798	>	* @param key key with which a value may be associated
2799	>	* @param remappingFunction the function to compute a value
2800	>	* @return the new value associated with the specified key, or null if none
2801	>	* @throws NullPointerException if the specified key or remappingFunction
2802	>	*         is null
2803	>	* @throws IllegalStateException if the computation detectably
2804	>	*         attempts a recursive update to this map that would
2805	>	*         otherwise never complete
2806	>	* @throws RuntimeException or Error if the remappingFunction does so,
2807	>	*         in which case the mapping is unchanged
2808	>	*/
2809	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2810	>	return internalCompute(key, true, remappingFunction);
2811	>	}
2812	>
2813	>	/**
2814	>	* Attempts to compute a mapping for the specified key and its
2815	>	* current mapped value (or {@code null} if there is no current
2816	>	* mapping). The entire method invocation is performed atomically.
2817	>	* Some attempted update operations on this map by other threads
2818	>	* may be blocked while computation is in progress, so the
2819	>	* computation should be short and simple, and must not attempt to
2820	>	* update any other mappings of this Map.
2821	>	*
2822	>	* @param key key with which the specified value is to be associated
2823	>	* @param remappingFunction the function to compute a value
2824	>	* @return the new value associated with the specified key, or null if none
2825	>	* @throws NullPointerException if the specified key or remappingFunction
2826	>	*         is null
2827	>	* @throws IllegalStateException if the computation detectably
2828	>	*         attempts a recursive update to this map that would
2829	>	*         otherwise never complete
2830	>	* @throws RuntimeException or Error if the remappingFunction does so,
2831	>	*         in which case the mapping is unchanged
2832	>	*/
2833	>	public V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2834	>	return internalCompute(key, false, remappingFunction);
2835	>	}
2836	>
2837	>	/**
2838	>	* If the specified key is not already associated with a
2839	>	* (non-null) value, associates it with the given value.
2840	>	* Otherwise, replaces the value with the results of the given
2841	>	* remapping function, or removes if {@code null}. The entire
2842	>	* method invocation is performed atomically.  Some attempted
2843	>	* update operations on this map by other threads may be blocked
2844	>	* while computation is in progress, so the computation should be
2845	>	* short and simple, and must not attempt to update any other
2846	>	* mappings of this Map.
2847	>	*
2848	>	* @param key key with which the specified value is to be associated
2849	>	* @param value the value to use if absent
2850	>	* @param remappingFunction the function to recompute a value if present
2851	>	* @return the new value associated with the specified key, or null if none
2852	>	* @throws NullPointerException if the specified key or the
2853	>	*         remappingFunction is null
2854	>	* @throws RuntimeException or Error if the remappingFunction does so,
2855	>	*         in which case the mapping is unchanged
2856	>	*/
2857	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
2858	>	return internalMerge(key, value, remappingFunction);
2859		}
2860
2861		/**
#	Line 1071 | Line 2863 | public class ConcurrentHashMap<K, V> ext
2863		* This method does nothing if the key is not in the map.
2864		*
2865		* @param  key the key that needs to be removed
2866	<	* @return the previous value associated with <tt>key</tt>, or
2867	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2866	>	* @return the previous value associated with {@code key}, or
2867	>	*         {@code null} if there was no mapping for {@code key}
2868		* @throws NullPointerException if the specified key is null
2869		*/
2870		public V remove(Object key) {
2871	<	int hash = hash(key.hashCode());
1080	<	Segment<K,V> s = segmentForHash(hash);
1081	<	return s == null ? null : s.remove(key, hash, null);
2871	>	return internalReplace(key, null, null);
2872		}
2873
2874		/**
#	Line 1087 | Line 2877 | public class ConcurrentHashMap<K, V> ext
2877		* @throws NullPointerException if the specified key is null
2878		*/
2879		public boolean remove(Object key, Object value) {
2880	<	int hash = hash(key.hashCode());
2881	<	Segment<K,V> s;
2882	<	return value != null && (s = segmentForHash(hash)) != null &&
1093	<	s.remove(key, hash, value) != null;
2880	>	if (key == null)
2881	>	throw new NullPointerException();
2882	>	return value != null && internalReplace(key, null, value) != null;
2883		}
2884
2885		/**
#	Line 1099 | Line 2888 | public class ConcurrentHashMap<K, V> ext
2888		* @throws NullPointerException if any of the arguments are null
2889		*/
2890		public boolean replace(K key, V oldValue, V newValue) {
2891	<	int hash = hash(key.hashCode());
1103	<	if (oldValue == null || newValue == null)
2891	>	if (key == null || oldValue == null || newValue == null)
2892		throw new NullPointerException();
2893	<	Segment<K,V> s = segmentForHash(hash);
1106	<	return s != null && s.replace(key, hash, oldValue, newValue);
2893	>	return internalReplace(key, newValue, oldValue) != null;
2894		}
2895
2896		/**
2897		* {@inheritDoc}
2898		*
2899		* @return the previous value associated with the specified key,
2900	<	*         or <tt>null</tt> if there was no mapping for the key
2900	>	*         or {@code null} if there was no mapping for the key
2901		* @throws NullPointerException if the specified key or value is null
2902		*/
2903		public V replace(K key, V value) {
2904	<	int hash = hash(key.hashCode());
1118	<	if (value == null)
2904	>	if (key == null || value == null)
2905		throw new NullPointerException();
2906	<	Segment<K,V> s = segmentForHash(hash);
1121	<	return s == null ? null : s.replace(key, hash, value);
2906	>	return internalReplace(key, value, null);
2907		}
2908
2909		/**
2910		* Removes all of the mappings from this map.
2911		*/
2912		public void clear() {
2913	<	final Segment<K,V>[] segments = this.segments;
1129	<	for (int j = 0; j < segments.length; ++j) {
1130	<	Segment<K,V> s = segmentAt(segments, j);
1131	<	if (s != null)
1132	<	s.clear();
1133	<	}
2913	>	internalClear();
2914		}
2915
2916		/**
2917		* Returns a {@link Set} view of the keys contained in this map.
2918		* The set is backed by the map, so changes to the map are
2919	<	* reflected in the set, and vice-versa.  The set supports element
2919	>	* reflected in the set, and vice-versa. The set supports element
2920		* removal, which removes the corresponding mapping from this map,
2921	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2922	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2923	<	* operations.  It does not support the <tt>add</tt> or
2924	<	* <tt>addAll</tt> operations.
2921	>	* via the {@code Iterator.remove}, {@code Set.remove},
2922	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
2923	>	* operations.  It does not support the {@code add} or
2924	>	* {@code addAll} operations.
2925		*
2926	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2926	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2927		* that will never throw {@link ConcurrentModificationException},
2928		* and guarantees to traverse elements as they existed upon
2929		* construction of the iterator, and may (but is not guaranteed to)
2930		* reflect any modifications subsequent to construction.
2931	+	*
2932	+	* @return the set view
2933	+	*/
2934	+	public KeySetView<K,V> keySet() {
2935	+	KeySetView<K,V> ks = keySet;
2936	+	return (ks != null) ? ks : (keySet = new KeySetView<K,V>(this, null));
2937	+	}
2938	+
2939	+	/**
2940	+	* Returns a {@link Set} view of the keys in this map, using the
2941	+	* given common mapped value for any additions (i.e., {@link
2942	+	* Collection#add} and {@link Collection#addAll(Collection)}).
2943	+	* This is of course only appropriate if it is acceptable to use
2944	+	* the same value for all additions from this view.
2945	+	*
2946	+	* @param mappedValue the mapped value to use for any additions
2947	+	* @return the set view
2948	+	* @throws NullPointerException if the mappedValue is null
2949		*/
2950	<	public Set<K> keySet() {
2951	<	Set<K> ks = keySet;
2952	<	return (ks != null) ? ks : (keySet = new KeySet());
2950	>	public KeySetView<K,V> keySet(V mappedValue) {
2951	>	if (mappedValue == null)
2952	>	throw new NullPointerException();
2953	>	return new KeySetView<K,V>(this, mappedValue);
2954		}
2955
2956		/**
#	Line 1159 | Line 2958 | public class ConcurrentHashMap<K, V> ext
2958		* The collection is backed by the map, so changes to the map are
2959		* reflected in the collection, and vice-versa.  The collection
2960		* supports element removal, which removes the corresponding
2961	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
2962	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
2963	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
2964	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
2961	>	* mapping from this map, via the {@code Iterator.remove},
2962	>	* {@code Collection.remove}, {@code removeAll},
2963	>	* {@code retainAll}, and {@code clear} operations.  It does not
2964	>	* support the {@code add} or {@code addAll} operations.
2965		*
2966	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2966	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2967		* that will never throw {@link ConcurrentModificationException},
2968		* and guarantees to traverse elements as they existed upon
2969		* construction of the iterator, and may (but is not guaranteed to)
2970		* reflect any modifications subsequent to construction.
2971	+	*
2972	+	* @return the collection view
2973		*/
2974		public Collection<V> values() {
2975	<	Collection<V> vs = values;
2976	<	return (vs != null) ? vs : (values = new Values());
2975	>	ValuesView<K,V> vs = values;
2976	>	return (vs != null) ? vs : (values = new ValuesView<K,V>(this));
2977		}
2978
2979		/**
#	Line 1180 | Line 2981 | public class ConcurrentHashMap<K, V> ext
2981		* The set is backed by the map, so changes to the map are
2982		* reflected in the set, and vice-versa.  The set supports element
2983		* removal, which removes the corresponding mapping from the map,
2984	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2985	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2986	<	* operations.  It does not support the <tt>add</tt> or
1186	<	* <tt>addAll</tt> operations.
2984	>	* via the {@code Iterator.remove}, {@code Set.remove},
2985	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
2986	>	* operations.
2987		*
2988	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2988	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2989		* that will never throw {@link ConcurrentModificationException},
2990		* and guarantees to traverse elements as they existed upon
2991		* construction of the iterator, and may (but is not guaranteed to)
2992		* reflect any modifications subsequent to construction.
2993	+	*
2994	+	* @return the set view
2995		*/
2996		public Set<Map.Entry<K,V>> entrySet() {
2997	<	Set<Map.Entry<K,V>> es = entrySet;
2998	<	return (es != null) ? es : (entrySet = new EntrySet());
2997	>	EntrySetView<K,V> es = entrySet;
2998	>	return (es != null) ? es : (entrySet = new EntrySetView<K,V>(this));
2999		}
3000
3001		/**
#	Line 1203 | Line 3005 | public class ConcurrentHashMap<K, V> ext
3005		* @see #keySet()
3006		*/
3007		public Enumeration<K> keys() {
3008	<	return new KeyIterator();
3008	>	Node<K,V>[] t;
3009	>	int f = (t = table) == null ? 0 : t.length;
3010	>	return new KeyIterator<K,V>(t, f, 0, f, this);
3011		}
3012
3013		/**
#	Line 1213 | Line 3017 | public class ConcurrentHashMap<K, V> ext
3017		* @see #values()
3018		*/
3019		public Enumeration<V> elements() {
3020	<	return new ValueIterator();
3020	>	Node<K,V>[] t;
3021	>	int f = (t = table) == null ? 0 : t.length;
3022	>	return new ValueIterator<K,V>(t, f, 0, f, this);
3023		}
3024
3025	<	/* ---------------- Iterator Support -------------- */
3025	>	/**
3026	>	* Returns the hash code value for this {@link Map}, i.e.,
3027	>	* the sum of, for each key-value pair in the map,
3028	>	* {@code key.hashCode() ^ value.hashCode()}.
3029	>	*
3030	>	* @return the hash code value for this map
3031	>	*/
3032	>	public int hashCode() {
3033	>	int h = 0;
3034	>	Node<K,V>[] t;
3035	>	if ((t = table) != null) {
3036	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
3037	>	for (Node<K,V> p; (p = it.advance()) != null; )
3038	>	h += p.key.hashCode() ^ p.val.hashCode();
3039	>	}
3040	>	return h;
3041	>	}
3042
3043	<	abstract class HashIterator {
3044	<	int nextSegmentIndex;
3045	<	int nextTableIndex;
3046	<	HashEntry<K,V>[] currentTable;
3047	<	HashEntry<K, V> nextEntry;
3048	<	HashEntry<K, V> lastReturned;
3043	>	/**
3044	>	* Returns a string representation of this map.  The string
3045	>	* representation consists of a list of key-value mappings (in no
3046	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
3047	>	* mappings are separated by the characters {@code ", "} (comma
3048	>	* and space).  Each key-value mapping is rendered as the key
3049	>	* followed by an equals sign ("{@code =}") followed by the
3050	>	* associated value.
3051	>	*
3052	>	* @return a string representation of this map
3053	>	*/
3054	>	public String toString() {
3055	>	Node<K,V>[] t;
3056	>	int f = (t = table) == null ? 0 : t.length;
3057	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
3058	>	StringBuilder sb = new StringBuilder();
3059	>	sb.append('{');
3060	>	Node<K,V> p;
3061	>	if ((p = it.advance()) != null) {
3062	>	for (;;) {
3063	>	K k = (K)p.key;
3064	>	V v = p.val;
3065	>	sb.append(k == this ? "(this Map)" : k);
3066	>	sb.append('=');
3067	>	sb.append(v == this ? "(this Map)" : v);
3068	>	if ((p = it.advance()) == null)
3069	>	break;
3070	>	sb.append(',').append(' ');
3071	>	}
3072	>	}
3073	>	return sb.append('}').toString();
3074	>	}
3075
3076	<	HashIterator() {
3077	<	nextSegmentIndex = segments.length - 1;
3078	<	nextTableIndex = -1;
3079	<	advance();
3076	>	/**
3077	>	* Compares the specified object with this map for equality.
3078	>	* Returns {@code true} if the given object is a map with the same
3079	>	* mappings as this map.  This operation may return misleading
3080	>	* results if either map is concurrently modified during execution
3081	>	* of this method.
3082	>	*
3083	>	* @param o object to be compared for equality with this map
3084	>	* @return {@code true} if the specified object is equal to this map
3085	>	*/
3086	>	public boolean equals(Object o) {
3087	>	if (o != this) {
3088	>	if (!(o instanceof Map))
3089	>	return false;
3090	>	Map<?,?> m = (Map<?,?>) o;
3091	>	Node<K,V>[] t;
3092	>	int f = (t = table) == null ? 0 : t.length;
3093	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
3094	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
3095	>	V val = p.val;
3096	>	Object v = m.get(p.key);
3097	>	if (v == null || (v != val && !v.equals(val)))
3098	>	return false;
3099	>	}
3100	>	for (Map.Entry<?,?> e : m.entrySet()) {
3101	>	Object mk, mv, v;
3102	>	if ((mk = e.getKey()) == null ||
3103	>	(mv = e.getValue()) == null ||
3104	>	(v = internalGet(mk)) == null ||
3105	>	(mv != v && !mv.equals(v)))
3106	>	return false;
3107	>	}
3108	>	}
3109	>	return true;
3110	>	}
3111	>
3112	>	/* ---------------- Serialization Support -------------- */
3113	>
3114	>	/**
3115	>	* Stripped-down version of helper class used in previous version,
3116	>	* declared for the sake of serialization compatibility
3117	>	*/
3118	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
3119	>	private static final long serialVersionUID = 2249069246763182397L;
3120	>	final float loadFactor;
3121	>	Segment(float lf) { this.loadFactor = lf; }
3122	>	}
3123	>
3124	>	/**
3125	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
3126	>	* stream (i.e., serializes it).
3127	>	* @param s the stream
3128	>	* @serialData
3129	>	* the key (Object) and value (Object)
3130	>	* for each key-value mapping, followed by a null pair.
3131	>	* The key-value mappings are emitted in no particular order.
3132	>	*/
3133	>	private void writeObject(java.io.ObjectOutputStream s)
3134	>	throws java.io.IOException {
3135	>	// For serialization compatibility
3136	>	// Emulate segment calculation from previous version of this class
3137	>	int sshift = 0;
3138	>	int ssize = 1;
3139	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
3140	>	++sshift;
3141	>	ssize <<= 1;
3142	>	}
3143	>	int segmentShift = 32 - sshift;
3144	>	int segmentMask = ssize - 1;
3145	>	Segment<K,V>[] segments = (Segment<K,V>[])
3146	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3147	>	for (int i = 0; i < segments.length; ++i)
3148	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
3149	>	s.putFields().put("segments", segments);
3150	>	s.putFields().put("segmentShift", segmentShift);
3151	>	s.putFields().put("segmentMask", segmentMask);
3152	>	s.writeFields();
3153	>
3154	>	Node<K,V>[] t;
3155	>	if ((t = table) != null) {
3156	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
3157	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
3158	>	s.writeObject(p.key);
3159	>	s.writeObject(p.val);
3160	>	}
3161	>	}
3162	>	s.writeObject(null);
3163	>	s.writeObject(null);
3164	>	segments = null; // throw away
3165	>	}
3166	>
3167	>	/**
3168	>	* Reconstitutes the instance from a stream (that is, deserializes it).
3169	>	* @param s the stream
3170	>	*/
3171	>	private void readObject(java.io.ObjectInputStream s)
3172	>	throws java.io.IOException, ClassNotFoundException {
3173	>	s.defaultReadObject();
3174	>
3175	>	// Create all nodes, then place in table once size is known
3176	>	long size = 0L;
3177	>	Node<K,V> p = null;
3178	>	for (;;) {
3179	>	K k = (K) s.readObject();
3180	>	V v = (V) s.readObject();
3181	>	if (k != null && v != null) {
3182	>	int h = spread(k.hashCode());
3183	>	p = new Node<K,V>(h, k, v, p);
3184	>	++size;
3185	>	}
3186	>	else
3187	>	break;
3188	>	}
3189	>	if (p != null) {
3190	>	boolean init = false;
3191	>	int n;
3192	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3193	>	n = MAXIMUM_CAPACITY;
3194	>	else {
3195	>	int sz = (int)size;
3196	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
3197	>	}
3198	>	int sc = sizeCtl;
3199	>	boolean collide = false;
3200	>	if (n > sc &&
3201	>	U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
3202	>	try {
3203	>	if (table == null) {
3204	>	init = true;
3205	>	Node<K,V>[] tab = (Node<K,V>[])new Node[n];
3206	>	int mask = n - 1;
3207	>	while (p != null) {
3208	>	int j = p.hash & mask;
3209	>	Node<K,V> next = p.next;
3210	>	Node<K,V> q = p.next = tabAt(tab, j);
3211	>	setTabAt(tab, j, p);
3212	>	if (!collide && q != null && q.hash == p.hash)
3213	>	collide = true;
3214	>	p = next;
3215	>	}
3216	>	table = tab;
3217	>	addCount(size, -1);
3218	>	sc = n - (n >>> 2);
3219	>	}
3220	>	} finally {
3221	>	sizeCtl = sc;
3222	>	}
3223	>	if (collide) { // rescan and convert to TreeBins
3224	>	Node<K,V>[] tab = table;
3225	>	for (int i = 0; i < tab.length; ++i) {
3226	>	int c = 0;
3227	>	for (Node<K,V> e = tabAt(tab, i); e != null; e = e.next) {
3228	>	if (++c > TREE_THRESHOLD &&
3229	>	(e.key instanceof Comparable)) {
3230	>	replaceWithTreeBin(tab, i, e.key);
3231	>	break;
3232	>	}
3233	>	}
3234	>	}
3235	>	}
3236	>	}
3237	>	if (!init) { // Can only happen if unsafely published.
3238	>	while (p != null) {
3239	>	internalPut((K)p.key, p.val, false);
3240	>	p = p.next;
3241	>	}
3242	>	}
3243	>	}
3244	>	}
3245	>
3246	>	// -------------------------------------------------------
3247	>
3248	>	// Overrides of other default Map methods
3249	>
3250	>	public void forEach(BiConsumer<? super K, ? super V> action) {
3251	>	if (action == null) throw new NullPointerException();
3252	>	Node<K,V>[] t;
3253	>	if ((t = table) != null) {
3254	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
3255	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
3256	>	action.accept((K)p.key, p.val);
3257	>	}
3258	>	}
3259	>	}
3260	>
3261	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
3262	>	if (function == null) throw new NullPointerException();
3263	>	Node<K,V>[] t;
3264	>	if ((t = table) != null) {
3265	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
3266	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
3267	>	K k = (K)p.key;
3268	>	internalPut(k, function.apply(k, p.val), false);
3269	>	}
3270	>	}
3271	>	}
3272	>
3273	>	// -------------------------------------------------------
3274	>
3275	>	// Parallel bulk operations
3276	>
3277	>	/**
3278	>	* Computes initial batch value for bulk tasks. The returned value
3279	>	* is approximately exp2 of the number of times (minus one) to
3280	>	* split task by two before executing leaf action. This value is
3281	>	* faster to compute and more convenient to use as a guide to
3282	>	* splitting than is the depth, since it is used while dividing by
3283	>	* two anyway.
3284	>	*/
3285	>	final int batchFor(long b) {
3286	>	long n;
3287	>	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3288	>	return 0;
3289	>	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3290	>	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3291	>	}
3292	>
3293	>	/**
3294	>	* Performs the given action for each (key, value).
3295	>	*
3296	>	* @param parallelismThreshold the (estimated) number of elements
3297	>	* needed for this operation to be executed in parallel
3298	>	* @param action the action
3299	>	* @since 1.8
3300	>	*/
3301	>	public void forEach(long parallelismThreshold,
3302	>	BiConsumer<? super K,? super V> action) {
3303	>	if (action == null) throw new NullPointerException();
3304	>	new ForEachMappingTask<K,V>
3305	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3306	>	action).invoke();
3307	>	}
3308	>
3309	>	/**
3310	>	* Performs the given action for each non-null transformation
3311	>	* of each (key, value).
3312	>	*
3313	>	* @param parallelismThreshold the (estimated) number of elements
3314	>	* needed for this operation to be executed in parallel
3315	>	* @param transformer a function returning the transformation
3316	>	* for an element, or null if there is no transformation (in
3317	>	* which case the action is not applied)
3318	>	* @param action the action
3319	>	* @since 1.8
3320	>	*/
3321	>	public <U> void forEach(long parallelismThreshold,
3322	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3323	>	Consumer<? super U> action) {
3324	>	if (transformer == null || action == null)
3325	>	throw new NullPointerException();
3326	>	new ForEachTransformedMappingTask<K,V,U>
3327	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3328	>	transformer, action).invoke();
3329	>	}
3330	>
3331	>	/**
3332	>	* Returns a non-null result from applying the given search
3333	>	* function on each (key, value), or null if none.  Upon
3334	>	* success, further element processing is suppressed and the
3335	>	* results of any other parallel invocations of the search
3336	>	* function are ignored.
3337	>	*
3338	>	* @param parallelismThreshold the (estimated) number of elements
3339	>	* needed for this operation to be executed in parallel
3340	>	* @param searchFunction a function returning a non-null
3341	>	* result on success, else null
3342	>	* @return a non-null result from applying the given search
3343	>	* function on each (key, value), or null if none
3344	>	* @since 1.8
3345	>	*/
3346	>	public <U> U search(long parallelismThreshold,
3347	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3348	>	if (searchFunction == null) throw new NullPointerException();
3349	>	return new SearchMappingsTask<K,V,U>
3350	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3351	>	searchFunction, new AtomicReference<U>()).invoke();
3352	>	}
3353	>
3354	>	/**
3355	>	* Returns the result of accumulating the given transformation
3356	>	* of all (key, value) pairs using the given reducer to
3357	>	* combine values, or null if none.
3358	>	*
3359	>	* @param parallelismThreshold the (estimated) number of elements
3360	>	* needed for this operation to be executed in parallel
3361	>	* @param transformer a function returning the transformation
3362	>	* for an element, or null if there is no transformation (in
3363	>	* which case it is not combined)
3364	>	* @param reducer a commutative associative combining function
3365	>	* @return the result of accumulating the given transformation
3366	>	* of all (key, value) pairs
3367	>	* @since 1.8
3368	>	*/
3369	>	public <U> U reduce(long parallelismThreshold,
3370	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3371	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3372	>	if (transformer == null || reducer == null)
3373	>	throw new NullPointerException();
3374	>	return new MapReduceMappingsTask<K,V,U>
3375	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3376	>	null, transformer, reducer).invoke();
3377	>	}
3378	>
3379	>	/**
3380	>	* Returns the result of accumulating the given transformation
3381	>	* of all (key, value) pairs using the given reducer to
3382	>	* combine values, and the given basis as an identity value.
3383	>	*
3384	>	* @param parallelismThreshold the (estimated) number of elements
3385	>	* needed for this operation to be executed in parallel
3386	>	* @param transformer a function returning the transformation
3387	>	* for an element
3388	>	* @param basis the identity (initial default value) for the reduction
3389	>	* @param reducer a commutative associative combining function
3390	>	* @return the result of accumulating the given transformation
3391	>	* of all (key, value) pairs
3392	>	* @since 1.8
3393	>	*/
3394	>	public double reduceToDoubleIn(long parallelismThreshold,
3395	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3396	>	double basis,
3397	>	DoubleBinaryOperator reducer) {
3398	>	if (transformer == null || reducer == null)
3399	>	throw new NullPointerException();
3400	>	return new MapReduceMappingsToDoubleTask<K,V>
3401	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3402	>	null, transformer, basis, reducer).invoke();
3403	>	}
3404	>
3405	>	/**
3406	>	* Returns the result of accumulating the given transformation
3407	>	* of all (key, value) pairs using the given reducer to
3408	>	* combine values, and the given basis as an identity value.
3409	>	*
3410	>	* @param parallelismThreshold the (estimated) number of elements
3411	>	* needed for this operation to be executed in parallel
3412	>	* @param transformer a function returning the transformation
3413	>	* for an element
3414	>	* @param basis the identity (initial default value) for the reduction
3415	>	* @param reducer a commutative associative combining function
3416	>	* @return the result of accumulating the given transformation
3417	>	* of all (key, value) pairs
3418	>	* @since 1.8
3419	>	*/
3420	>	public long reduceToLong(long parallelismThreshold,
3421	>	ToLongBiFunction<? super K, ? super V> transformer,
3422	>	long basis,
3423	>	LongBinaryOperator reducer) {
3424	>	if (transformer == null || reducer == null)
3425	>	throw new NullPointerException();
3426	>	return new MapReduceMappingsToLongTask<K,V>
3427	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3428	>	null, transformer, basis, reducer).invoke();
3429	>	}
3430	>
3431	>	/**
3432	>	* Returns the result of accumulating the given transformation
3433	>	* of all (key, value) pairs using the given reducer to
3434	>	* combine values, and the given basis as an identity value.
3435	>	*
3436	>	* @param parallelismThreshold the (estimated) number of elements
3437	>	* needed for this operation to be executed in parallel
3438	>	* @param transformer a function returning the transformation
3439	>	* for an element
3440	>	* @param basis the identity (initial default value) for the reduction
3441	>	* @param reducer a commutative associative combining function
3442	>	* @return the result of accumulating the given transformation
3443	>	* of all (key, value) pairs
3444	>	* @since 1.8
3445	>	*/
3446	>	public int reduceToInt(long parallelismThreshold,
3447	>	ToIntBiFunction<? super K, ? super V> transformer,
3448	>	int basis,
3449	>	IntBinaryOperator reducer) {
3450	>	if (transformer == null || reducer == null)
3451	>	throw new NullPointerException();
3452	>	return new MapReduceMappingsToIntTask<K,V>
3453	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3454	>	null, transformer, basis, reducer).invoke();
3455	>	}
3456	>
3457	>	/**
3458	>	* Performs the given action for each key.
3459	>	*
3460	>	* @param parallelismThreshold the (estimated) number of elements
3461	>	* needed for this operation to be executed in parallel
3462	>	* @param action the action
3463	>	* @since 1.8
3464	>	*/
3465	>	public void forEachKey(long parallelismThreshold,
3466	>	Consumer<? super K> action) {
3467	>	if (action == null) throw new NullPointerException();
3468	>	new ForEachKeyTask<K,V>
3469	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3470	>	action).invoke();
3471	>	}
3472	>
3473	>	/**
3474	>	* Performs the given action for each non-null transformation
3475	>	* of each key.
3476	>	*
3477	>	* @param parallelismThreshold the (estimated) number of elements
3478	>	* needed for this operation to be executed in parallel
3479	>	* @param transformer a function returning the transformation
3480	>	* for an element, or null if there is no transformation (in
3481	>	* which case the action is not applied)
3482	>	* @param action the action
3483	>	* @since 1.8
3484	>	*/
3485	>	public <U> void forEachKey(long parallelismThreshold,
3486	>	Function<? super K, ? extends U> transformer,
3487	>	Consumer<? super U> action) {
3488	>	if (transformer == null || action == null)
3489	>	throw new NullPointerException();
3490	>	new ForEachTransformedKeyTask<K,V,U>
3491	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3492	>	transformer, action).invoke();
3493	>	}
3494	>
3495	>	/**
3496	>	* Returns a non-null result from applying the given search
3497	>	* function on each key, or null if none. Upon success,
3498	>	* further element processing is suppressed and the results of
3499	>	* any other parallel invocations of the search function are
3500	>	* ignored.
3501	>	*
3502	>	* @param parallelismThreshold the (estimated) number of elements
3503	>	* needed for this operation to be executed in parallel
3504	>	* @param searchFunction a function returning a non-null
3505	>	* result on success, else null
3506	>	* @return a non-null result from applying the given search
3507	>	* function on each key, or null if none
3508	>	* @since 1.8
3509	>	*/
3510	>	public <U> U searchKeys(long parallelismThreshold,
3511	>	Function<? super K, ? extends U> searchFunction) {
3512	>	if (searchFunction == null) throw new NullPointerException();
3513	>	return new SearchKeysTask<K,V,U>
3514	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3515	>	searchFunction, new AtomicReference<U>()).invoke();
3516	>	}
3517	>
3518	>	/**
3519	>	* Returns the result of accumulating all keys using the given
3520	>	* reducer to combine values, or null if none.
3521	>	*
3522	>	* @param parallelismThreshold the (estimated) number of elements
3523	>	* needed for this operation to be executed in parallel
3524	>	* @param reducer a commutative associative combining function
3525	>	* @return the result of accumulating all keys using the given
3526	>	* reducer to combine values, or null if none
3527	>	* @since 1.8
3528	>	*/
3529	>	public K reduceKeys(long parallelismThreshold,
3530	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3531	>	if (reducer == null) throw new NullPointerException();
3532	>	return new ReduceKeysTask<K,V>
3533	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3534	>	null, reducer).invoke();
3535	>	}
3536	>
3537	>	/**
3538	>	* Returns the result of accumulating the given transformation
3539	>	* of all keys using the given reducer to combine values, or
3540	>	* null if none.
3541	>	*
3542	>	* @param parallelismThreshold the (estimated) number of elements
3543	>	* needed for this operation to be executed in parallel
3544	>	* @param transformer a function returning the transformation
3545	>	* for an element, or null if there is no transformation (in
3546	>	* which case it is not combined)
3547	>	* @param reducer a commutative associative combining function
3548	>	* @return the result of accumulating the given transformation
3549	>	* of all keys
3550	>	* @since 1.8
3551	>	*/
3552	>	public <U> U reduceKeys(long parallelismThreshold,
3553	>	Function<? super K, ? extends U> transformer,
3554	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3555	>	if (transformer == null || reducer == null)
3556	>	throw new NullPointerException();
3557	>	return new MapReduceKeysTask<K,V,U>
3558	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3559	>	null, transformer, reducer).invoke();
3560	>	}
3561	>
3562	>	/**
3563	>	* Returns the result of accumulating the given transformation
3564	>	* of all keys using the given reducer to combine values, and
3565	>	* the given basis as an identity value.
3566	>	*
3567	>	* @param parallelismThreshold the (estimated) number of elements
3568	>	* needed for this operation to be executed in parallel
3569	>	* @param transformer a function returning the transformation
3570	>	* for an element
3571	>	* @param basis the identity (initial default value) for the reduction
3572	>	* @param reducer a commutative associative combining function
3573	>	* @return the result of accumulating the given transformation
3574	>	* of all keys
3575	>	* @since 1.8
3576	>	*/
3577	>	public double reduceKeysToDouble(long parallelismThreshold,
3578	>	ToDoubleFunction<? super K> transformer,
3579	>	double basis,
3580	>	DoubleBinaryOperator reducer) {
3581	>	if (transformer == null || reducer == null)
3582	>	throw new NullPointerException();
3583	>	return new MapReduceKeysToDoubleTask<K,V>
3584	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3585	>	null, transformer, basis, reducer).invoke();
3586	>	}
3587	>
3588	>	/**
3589	>	* Returns the result of accumulating the given transformation
3590	>	* of all keys using the given reducer to combine values, and
3591	>	* the given basis as an identity value.
3592	>	*
3593	>	* @param parallelismThreshold the (estimated) number of elements
3594	>	* needed for this operation to be executed in parallel
3595	>	* @param transformer a function returning the transformation
3596	>	* for an element
3597	>	* @param basis the identity (initial default value) for the reduction
3598	>	* @param reducer a commutative associative combining function
3599	>	* @return the result of accumulating the given transformation
3600	>	* of all keys
3601	>	* @since 1.8
3602	>	*/
3603	>	public long reduceKeysToLong(long parallelismThreshold,
3604	>	ToLongFunction<? super K> transformer,
3605	>	long basis,
3606	>	LongBinaryOperator reducer) {
3607	>	if (transformer == null || reducer == null)
3608	>	throw new NullPointerException();
3609	>	return new MapReduceKeysToLongTask<K,V>
3610	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3611	>	null, transformer, basis, reducer).invoke();
3612	>	}
3613	>
3614	>	/**
3615	>	* Returns the result of accumulating the given transformation
3616	>	* of all keys using the given reducer to combine values, and
3617	>	* the given basis as an identity value.
3618	>	*
3619	>	* @param parallelismThreshold the (estimated) number of elements
3620	>	* needed for this operation to be executed in parallel
3621	>	* @param transformer a function returning the transformation
3622	>	* for an element
3623	>	* @param basis the identity (initial default value) for the reduction
3624	>	* @param reducer a commutative associative combining function
3625	>	* @return the result of accumulating the given transformation
3626	>	* of all keys
3627	>	* @since 1.8
3628	>	*/
3629	>	public int reduceKeysToInt(long parallelismThreshold,
3630	>	ToIntFunction<? super K> transformer,
3631	>	int basis,
3632	>	IntBinaryOperator reducer) {
3633	>	if (transformer == null || reducer == null)
3634	>	throw new NullPointerException();
3635	>	return new MapReduceKeysToIntTask<K,V>
3636	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3637	>	null, transformer, basis, reducer).invoke();
3638	>	}
3639	>
3640	>	/**
3641	>	* Performs the given action for each value.
3642	>	*
3643	>	* @param parallelismThreshold the (estimated) number of elements
3644	>	* needed for this operation to be executed in parallel
3645	>	* @param action the action
3646	>	* @since 1.8
3647	>	*/
3648	>	public void forEachValue(long parallelismThreshold,
3649	>	Consumer<? super V> action) {
3650	>	if (action == null)
3651	>	throw new NullPointerException();
3652	>	new ForEachValueTask<K,V>
3653	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3654	>	action).invoke();
3655	>	}
3656	>
3657	>	/**
3658	>	* Performs the given action for each non-null transformation
3659	>	* of each value.
3660	>	*
3661	>	* @param parallelismThreshold the (estimated) number of elements
3662	>	* needed for this operation to be executed in parallel
3663	>	* @param transformer a function returning the transformation
3664	>	* for an element, or null if there is no transformation (in
3665	>	* which case the action is not applied)
3666	>	* @param action the action
3667	>	* @since 1.8
3668	>	*/
3669	>	public <U> void forEachValue(long parallelismThreshold,
3670	>	Function<? super V, ? extends U> transformer,
3671	>	Consumer<? super U> action) {
3672	>	if (transformer == null || action == null)
3673	>	throw new NullPointerException();
3674	>	new ForEachTransformedValueTask<K,V,U>
3675	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3676	>	transformer, action).invoke();
3677	>	}
3678	>
3679	>	/**
3680	>	* Returns a non-null result from applying the given search
3681	>	* function on each value, or null if none.  Upon success,
3682	>	* further element processing is suppressed and the results of
3683	>	* any other parallel invocations of the search function are
3684	>	* ignored.
3685	>	*
3686	>	* @param parallelismThreshold the (estimated) number of elements
3687	>	* needed for this operation to be executed in parallel
3688	>	* @param searchFunction a function returning a non-null
3689	>	* result on success, else null
3690	>	* @return a non-null result from applying the given search
3691	>	* function on each value, or null if none
3692	>	* @since 1.8
3693	>	*/
3694	>	public <U> U searchValues(long parallelismThreshold,
3695	>	Function<? super V, ? extends U> searchFunction) {
3696	>	if (searchFunction == null) throw new NullPointerException();
3697	>	return new SearchValuesTask<K,V,U>
3698	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3699	>	searchFunction, new AtomicReference<U>()).invoke();
3700	>	}
3701	>
3702	>	/**
3703	>	* Returns the result of accumulating all values using the
3704	>	* given reducer to combine values, or null if none.
3705	>	*
3706	>	* @param parallelismThreshold the (estimated) number of elements
3707	>	* needed for this operation to be executed in parallel
3708	>	* @param reducer a commutative associative combining function
3709	>	* @return the result of accumulating all values
3710	>	* @since 1.8
3711	>	*/
3712	>	public V reduceValues(long parallelismThreshold,
3713	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
3714	>	if (reducer == null) throw new NullPointerException();
3715	>	return new ReduceValuesTask<K,V>
3716	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3717	>	null, reducer).invoke();
3718	>	}
3719	>
3720	>	/**
3721	>	* Returns the result of accumulating the given transformation
3722	>	* of all values using the given reducer to combine values, or
3723	>	* null if none.
3724	>	*
3725	>	* @param parallelismThreshold the (estimated) number of elements
3726	>	* needed for this operation to be executed in parallel
3727	>	* @param transformer a function returning the transformation
3728	>	* for an element, or null if there is no transformation (in
3729	>	* which case it is not combined)
3730	>	* @param reducer a commutative associative combining function
3731	>	* @return the result of accumulating the given transformation
3732	>	* of all values
3733	>	* @since 1.8
3734	>	*/
3735	>	public <U> U reduceValues(long parallelismThreshold,
3736	>	Function<? super V, ? extends U> transformer,
3737	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3738	>	if (transformer == null || reducer == null)
3739	>	throw new NullPointerException();
3740	>	return new MapReduceValuesTask<K,V,U>
3741	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3742	>	null, transformer, reducer).invoke();
3743	>	}
3744	>
3745	>	/**
3746	>	* Returns the result of accumulating the given transformation
3747	>	* of all values using the given reducer to combine values,
3748	>	* and the given basis as an identity value.
3749	>	*
3750	>	* @param parallelismThreshold the (estimated) number of elements
3751	>	* needed for this operation to be executed in parallel
3752	>	* @param transformer a function returning the transformation
3753	>	* for an element
3754	>	* @param basis the identity (initial default value) for the reduction
3755	>	* @param reducer a commutative associative combining function
3756	>	* @return the result of accumulating the given transformation
3757	>	* of all values
3758	>	* @since 1.8
3759	>	*/
3760	>	public double reduceValuesToDouble(long parallelismThreshold,
3761	>	ToDoubleFunction<? super V> transformer,
3762	>	double basis,
3763	>	DoubleBinaryOperator reducer) {
3764	>	if (transformer == null || reducer == null)
3765	>	throw new NullPointerException();
3766	>	return new MapReduceValuesToDoubleTask<K,V>
3767	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3768	>	null, transformer, basis, reducer).invoke();
3769	>	}
3770	>
3771	>	/**
3772	>	* Returns the result of accumulating the given transformation
3773	>	* of all values using the given reducer to combine values,
3774	>	* and the given basis as an identity value.
3775	>	*
3776	>	* @param parallelismThreshold the (estimated) number of elements
3777	>	* needed for this operation to be executed in parallel
3778	>	* @param transformer a function returning the transformation
3779	>	* for an element
3780	>	* @param basis the identity (initial default value) for the reduction
3781	>	* @param reducer a commutative associative combining function
3782	>	* @return the result of accumulating the given transformation
3783	>	* of all values
3784	>	* @since 1.8
3785	>	*/
3786	>	public long reduceValuesToLong(long parallelismThreshold,
3787	>	ToLongFunction<? super V> transformer,
3788	>	long basis,
3789	>	LongBinaryOperator reducer) {
3790	>	if (transformer == null || reducer == null)
3791	>	throw new NullPointerException();
3792	>	return new MapReduceValuesToLongTask<K,V>
3793	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3794	>	null, transformer, basis, reducer).invoke();
3795	>	}
3796	>
3797	>	/**
3798	>	* Returns the result of accumulating the given transformation
3799	>	* of all values using the given reducer to combine values,
3800	>	* and the given basis as an identity value.
3801	>	*
3802	>	* @param parallelismThreshold the (estimated) number of elements
3803	>	* needed for this operation to be executed in parallel
3804	>	* @param transformer a function returning the transformation
3805	>	* for an element
3806	>	* @param basis the identity (initial default value) for the reduction
3807	>	* @param reducer a commutative associative combining function
3808	>	* @return the result of accumulating the given transformation
3809	>	* of all values
3810	>	* @since 1.8
3811	>	*/
3812	>	public int reduceValuesToInt(long parallelismThreshold,
3813	>	ToIntFunction<? super V> transformer,
3814	>	int basis,
3815	>	IntBinaryOperator reducer) {
3816	>	if (transformer == null || reducer == null)
3817	>	throw new NullPointerException();
3818	>	return new MapReduceValuesToIntTask<K,V>
3819	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3820	>	null, transformer, basis, reducer).invoke();
3821	>	}
3822	>
3823	>	/**
3824	>	* Performs the given action for each entry.
3825	>	*
3826	>	* @param parallelismThreshold the (estimated) number of elements
3827	>	* needed for this operation to be executed in parallel
3828	>	* @param action the action
3829	>	* @since 1.8
3830	>	*/
3831	>	public void forEachEntry(long parallelismThreshold,
3832	>	Consumer<? super Map.Entry<K,V>> action) {
3833	>	if (action == null) throw new NullPointerException();
3834	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
3835	>	action).invoke();
3836	>	}
3837	>
3838	>	/**
3839	>	* Performs the given action for each non-null transformation
3840	>	* of each entry.
3841	>	*
3842	>	* @param parallelismThreshold the (estimated) number of elements
3843	>	* needed for this operation to be executed in parallel
3844	>	* @param transformer a function returning the transformation
3845	>	* for an element, or null if there is no transformation (in
3846	>	* which case the action is not applied)
3847	>	* @param action the action
3848	>	* @since 1.8
3849	>	*/
3850	>	public <U> void forEachEntry(long parallelismThreshold,
3851	>	Function<Map.Entry<K,V>, ? extends U> transformer,
3852	>	Consumer<? super U> action) {
3853	>	if (transformer == null || action == null)
3854	>	throw new NullPointerException();
3855	>	new ForEachTransformedEntryTask<K,V,U>
3856	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3857	>	transformer, action).invoke();
3858	>	}
3859	>
3860	>	/**
3861	>	* Returns a non-null result from applying the given search
3862	>	* function on each entry, or null if none.  Upon success,
3863	>	* further element processing is suppressed and the results of
3864	>	* any other parallel invocations of the search function are
3865	>	* ignored.
3866	>	*
3867	>	* @param parallelismThreshold the (estimated) number of elements
3868	>	* needed for this operation to be executed in parallel
3869	>	* @param searchFunction a function returning a non-null
3870	>	* result on success, else null
3871	>	* @return a non-null result from applying the given search
3872	>	* function on each entry, or null if none
3873	>	* @since 1.8
3874	>	*/
3875	>	public <U> U searchEntries(long parallelismThreshold,
3876	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
3877	>	if (searchFunction == null) throw new NullPointerException();
3878	>	return new SearchEntriesTask<K,V,U>
3879	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3880	>	searchFunction, new AtomicReference<U>()).invoke();
3881	>	}
3882	>
3883	>	/**
3884	>	* Returns the result of accumulating all entries using the
3885	>	* given reducer to combine values, or null if none.
3886	>	*
3887	>	* @param parallelismThreshold the (estimated) number of elements
3888	>	* needed for this operation to be executed in parallel
3889	>	* @param reducer a commutative associative combining function
3890	>	* @return the result of accumulating all entries
3891	>	* @since 1.8
3892	>	*/
3893	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
3894	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
3895	>	if (reducer == null) throw new NullPointerException();
3896	>	return new ReduceEntriesTask<K,V>
3897	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3898	>	null, reducer).invoke();
3899	>	}
3900	>
3901	>	/**
3902	>	* Returns the result of accumulating the given transformation
3903	>	* of all entries using the given reducer to combine values,
3904	>	* or null if none.
3905	>	*
3906	>	* @param parallelismThreshold the (estimated) number of elements
3907	>	* needed for this operation to be executed in parallel
3908	>	* @param transformer a function returning the transformation
3909	>	* for an element, or null if there is no transformation (in
3910	>	* which case it is not combined)
3911	>	* @param reducer a commutative associative combining function
3912	>	* @return the result of accumulating the given transformation
3913	>	* of all entries
3914	>	* @since 1.8
3915	>	*/
3916	>	public <U> U reduceEntries(long parallelismThreshold,
3917	>	Function<Map.Entry<K,V>, ? extends U> transformer,
3918	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3919	>	if (transformer == null || reducer == null)
3920	>	throw new NullPointerException();
3921	>	return new MapReduceEntriesTask<K,V,U>
3922	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3923	>	null, transformer, reducer).invoke();
3924	>	}
3925	>
3926	>	/**
3927	>	* Returns the result of accumulating the given transformation
3928	>	* of all entries using the given reducer to combine values,
3929	>	* and the given basis as an identity value.
3930	>	*
3931	>	* @param parallelismThreshold the (estimated) number of elements
3932	>	* needed for this operation to be executed in parallel
3933	>	* @param transformer a function returning the transformation
3934	>	* for an element
3935	>	* @param basis the identity (initial default value) for the reduction
3936	>	* @param reducer a commutative associative combining function
3937	>	* @return the result of accumulating the given transformation
3938	>	* of all entries
3939	>	* @since 1.8
3940	>	*/
3941	>	public double reduceEntriesToDouble(long parallelismThreshold,
3942	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
3943	>	double basis,
3944	>	DoubleBinaryOperator reducer) {
3945	>	if (transformer == null || reducer == null)
3946	>	throw new NullPointerException();
3947	>	return new MapReduceEntriesToDoubleTask<K,V>
3948	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3949	>	null, transformer, basis, reducer).invoke();
3950	>	}
3951	>
3952	>	/**
3953	>	* Returns the result of accumulating the given transformation
3954	>	* of all entries using the given reducer to combine values,
3955	>	* and the given basis as an identity value.
3956	>	*
3957	>	* @param parallelismThreshold the (estimated) number of elements
3958	>	* needed for this operation to be executed in parallel
3959	>	* @param transformer a function returning the transformation
3960	>	* for an element
3961	>	* @param basis the identity (initial default value) for the reduction
3962	>	* @param reducer a commutative associative combining function
3963	>	* @return the result of accumulating the given transformation
3964	>	* of all entries
3965	>	* @since 1.8
3966	>	*/
3967	>	public long reduceEntriesToLong(long parallelismThreshold,
3968	>	ToLongFunction<Map.Entry<K,V>> transformer,
3969	>	long basis,
3970	>	LongBinaryOperator reducer) {
3971	>	if (transformer == null || reducer == null)
3972	>	throw new NullPointerException();
3973	>	return new MapReduceEntriesToLongTask<K,V>
3974	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3975	>	null, transformer, basis, reducer).invoke();
3976	>	}
3977	>
3978	>	/**
3979	>	* Returns the result of accumulating the given transformation
3980	>	* of all entries using the given reducer to combine values,
3981	>	* and the given basis as an identity value.
3982	>	*
3983	>	* @param parallelismThreshold the (estimated) number of elements
3984	>	* needed for this operation to be executed in parallel
3985	>	* @param transformer a function returning the transformation
3986	>	* for an element
3987	>	* @param basis the identity (initial default value) for the reduction
3988	>	* @param reducer a commutative associative combining function
3989	>	* @return the result of accumulating the given transformation
3990	>	* of all entries
3991	>	* @since 1.8
3992	>	*/
3993	>	public int reduceEntriesToInt(long parallelismThreshold,
3994	>	ToIntFunction<Map.Entry<K,V>> transformer,
3995	>	int basis,
3996	>	IntBinaryOperator reducer) {
3997	>	if (transformer == null || reducer == null)
3998	>	throw new NullPointerException();
3999	>	return new MapReduceEntriesToIntTask<K,V>
4000	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4001	>	null, transformer, basis, reducer).invoke();
4002	>	}
4003	>
4004	>
4005	>	/* ----------------Views -------------- */
4006	>
4007	>	/**
4008	>	* Base class for views.
4009	>	*/
4010	>	abstract static class CollectionView<K,V,E>
4011	>	implements Collection<E>, java.io.Serializable {
4012	>	private static final long serialVersionUID = 7249069246763182397L;
4013	>	final ConcurrentHashMap<K,V> map;
4014	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4015	>
4016	>	/**
4017	>	* Returns the map backing this view.
4018	>	*
4019	>	* @return the map backing this view
4020	>	*/
4021	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4022	>
4023	>	/**
4024	>	* Removes all of the elements from this view, by removing all
4025	>	* the mappings from the map backing this view.
4026	>	*/
4027	>	public final void clear()      { map.clear(); }
4028	>	public final int size()        { return map.size(); }
4029	>	public final boolean isEmpty() { return map.isEmpty(); }
4030	>
4031	>	// implementations below rely on concrete classes supplying these
4032	>	// abstract methods
4033	>	/**
4034	>	* Returns a "weakly consistent" iterator that will never
4035	>	* throw {@link ConcurrentModificationException}, and
4036	>	* guarantees to traverse elements as they existed upon
4037	>	* construction of the iterator, and may (but is not
4038	>	* guaranteed to) reflect any modifications subsequent to
4039	>	* construction.
4040	>	*/
4041	>	public abstract Iterator<E> iterator();
4042	>	public abstract boolean contains(Object o);
4043	>	public abstract boolean remove(Object o);
4044	>
4045	>	private static final String oomeMsg = "Required array size too large";
4046	>
4047	>	public final Object[] toArray() {
4048	>	long sz = map.mappingCount();
4049	>	if (sz > MAX_ARRAY_SIZE)
4050	>	throw new OutOfMemoryError(oomeMsg);
4051	>	int n = (int)sz;
4052	>	Object[] r = new Object[n];
4053	>	int i = 0;
4054	>	for (E e : this) {
4055	>	if (i == n) {
4056	>	if (n >= MAX_ARRAY_SIZE)
4057	>	throw new OutOfMemoryError(oomeMsg);
4058	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4059	>	n = MAX_ARRAY_SIZE;
4060	>	else
4061	>	n += (n >>> 1) + 1;
4062	>	r = Arrays.copyOf(r, n);
4063	>	}
4064	>	r[i++] = e;
4065	>	}
4066	>	return (i == n) ? r : Arrays.copyOf(r, i);
4067	>	}
4068	>
4069	>	public final <T> T[] toArray(T[] a) {
4070	>	long sz = map.mappingCount();
4071	>	if (sz > MAX_ARRAY_SIZE)
4072	>	throw new OutOfMemoryError(oomeMsg);
4073	>	int m = (int)sz;
4074	>	T[] r = (a.length >= m) ? a :
4075	>	(T[])java.lang.reflect.Array
4076	>	.newInstance(a.getClass().getComponentType(), m);
4077	>	int n = r.length;
4078	>	int i = 0;
4079	>	for (E e : this) {
4080	>	if (i == n) {
4081	>	if (n >= MAX_ARRAY_SIZE)
4082	>	throw new OutOfMemoryError(oomeMsg);
4083	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4084	>	n = MAX_ARRAY_SIZE;
4085	>	else
4086	>	n += (n >>> 1) + 1;
4087	>	r = Arrays.copyOf(r, n);
4088	>	}
4089	>	r[i++] = (T)e;
4090	>	}
4091	>	if (a == r && i < n) {
4092	>	r[i] = null; // null-terminate
4093	>	return r;
4094	>	}
4095	>	return (i == n) ? r : Arrays.copyOf(r, i);
4096		}
4097
4098		/**
4099	<	* Sets nextEntry to first node of next non-empty table
4100	<	* (in backwards order, to simplify checks).
4099	>	* Returns a string representation of this collection.
4100	>	* The string representation consists of the string representations
4101	>	* of the collection's elements in the order they are returned by
4102	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4103	>	* Adjacent elements are separated by the characters {@code ", "}
4104	>	* (comma and space).  Elements are converted to strings as by
4105	>	* {@link String#valueOf(Object)}.
4106	>	*
4107	>	* @return a string representation of this collection
4108		*/
4109	<	final void advance() {
4110	<	for (;;) {
4111	<	if (nextTableIndex >= 0) {
4112	<	if ((nextEntry = entryAt(currentTable,
4113	<	nextTableIndex--)) != null)
4109	>	public final String toString() {
4110	>	StringBuilder sb = new StringBuilder();
4111	>	sb.append('[');
4112	>	Iterator<E> it = iterator();
4113	>	if (it.hasNext()) {
4114	>	for (;;) {
4115	>	Object e = it.next();
4116	>	sb.append(e == this ? "(this Collection)" : e);
4117	>	if (!it.hasNext())
4118		break;
4119	+	sb.append(',').append(' ');
4120		}
4121	<	else if (nextSegmentIndex >= 0) {
4122	<	Segment<K,V> seg = segmentAt(segments, nextSegmentIndex--);
4123	<	if (seg != null && (currentTable = seg.table) != null)
4124	<	nextTableIndex = currentTable.length - 1;
4121	>	}
4122	>	return sb.append(']').toString();
4123	>	}
4124	>
4125	>	public final boolean containsAll(Collection<?> c) {
4126	>	if (c != this) {
4127	>	for (Object e : c) {
4128	>	if (e == null || !contains(e))
4129	>	return false;
4130		}
1250	–	else
1251	–	break;
4131		}
4132	+	return true;
4133		}
4134
4135	<	final HashEntry<K,V> nextEntry() {
4136	<	HashEntry<K,V> e = nextEntry;
4137	<	if (e == null)
4138	<	throw new NoSuchElementException();
4139	<	lastReturned = e; // cannot assign until after null check
4140	<	if ((nextEntry = e.next) == null)
4141	<	advance();
4142	<	return e;
4135	>	public final boolean removeAll(Collection<?> c) {
4136	>	boolean modified = false;
4137	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4138	>	if (c.contains(it.next())) {
4139	>	it.remove();
4140	>	modified = true;
4141	>	}
4142	>	}
4143	>	return modified;
4144		}
4145
4146	<	public final boolean hasNext() { return nextEntry != null; }
4147	<	public final boolean hasMoreElements() { return nextEntry != null; }
4146	>	public final boolean retainAll(Collection<?> c) {
4147	>	boolean modified = false;
4148	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4149	>	if (!c.contains(it.next())) {
4150	>	it.remove();
4151	>	modified = true;
4152	>	}
4153	>	}
4154	>	return modified;
4155	>	}
4156
4157	<	public final void remove() {
4158	<	if (lastReturned == null)
4159	<	throw new IllegalStateException();
4160	<	ConcurrentHashMap.this.remove(lastReturned.key);
4161	<	lastReturned = null;
4157	>	}
4158	>
4159	>	/**
4160	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4161	>	* which additions may optionally be enabled by mapping to a
4162	>	* common value.  This class cannot be directly instantiated.
4163	>	* See {@link #keySet() keySet()},
4164	>	* {@link #keySet(Object) keySet(V)},
4165	>	* {@link #newKeySet() newKeySet()},
4166	>	* {@link #newKeySet(int) newKeySet(int)}.
4167	>	*
4168	>	* @since 1.8
4169	>	*/
4170	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4171	>	implements Set<K>, java.io.Serializable {
4172	>	private static final long serialVersionUID = 7249069246763182397L;
4173	>	private final V value;
4174	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4175	>	super(map);
4176	>	this.value = value;
4177	>	}
4178	>
4179	>	/**
4180	>	* Returns the default mapped value for additions,
4181	>	* or {@code null} if additions are not supported.
4182	>	*
4183	>	* @return the default mapped value for additions, or {@code null}
4184	>	* if not supported
4185	>	*/
4186	>	public V getMappedValue() { return value; }
4187	>
4188	>	/**
4189	>	* {@inheritDoc}
4190	>	* @throws NullPointerException if the specified key is null
4191	>	*/
4192	>	public boolean contains(Object o) { return map.containsKey(o); }
4193	>
4194	>	/**
4195	>	* Removes the key from this map view, by removing the key (and its
4196	>	* corresponding value) from the backing map.  This method does
4197	>	* nothing if the key is not in the map.
4198	>	*
4199	>	* @param  o the key to be removed from the backing map
4200	>	* @return {@code true} if the backing map contained the specified key
4201	>	* @throws NullPointerException if the specified key is null
4202	>	*/
4203	>	public boolean remove(Object o) { return map.remove(o) != null; }
4204	>
4205	>	/**
4206	>	* @return an iterator over the keys of the backing map
4207	>	*/
4208	>	public Iterator<K> iterator() {
4209	>	Node<K,V>[] t;
4210	>	ConcurrentHashMap<K,V> m = map;
4211	>	int f = (t = m.table) == null ? 0 : t.length;
4212	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4213	>	}
4214	>
4215	>	/**
4216	>	* Adds the specified key to this set view by mapping the key to
4217	>	* the default mapped value in the backing map, if defined.
4218	>	*
4219	>	* @param e key to be added
4220	>	* @return {@code true} if this set changed as a result of the call
4221	>	* @throws NullPointerException if the specified key is null
4222	>	* @throws UnsupportedOperationException if no default mapped value
4223	>	* for additions was provided
4224	>	*/
4225	>	public boolean add(K e) {
4226	>	V v;
4227	>	if ((v = value) == null)
4228	>	throw new UnsupportedOperationException();
4229	>	return map.internalPut(e, v, true) == null;
4230	>	}
4231	>
4232	>	/**
4233	>	* Adds all of the elements in the specified collection to this set,
4234	>	* as if by calling {@link #add} on each one.
4235	>	*
4236	>	* @param c the elements to be inserted into this set
4237	>	* @return {@code true} if this set changed as a result of the call
4238	>	* @throws NullPointerException if the collection or any of its
4239	>	* elements are {@code null}
4240	>	* @throws UnsupportedOperationException if no default mapped value
4241	>	* for additions was provided
4242	>	*/
4243	>	public boolean addAll(Collection<? extends K> c) {
4244	>	boolean added = false;
4245	>	V v;
4246	>	if ((v = value) == null)
4247	>	throw new UnsupportedOperationException();
4248	>	for (K e : c) {
4249	>	if (map.internalPut(e, v, true) == null)
4250	>	added = true;
4251	>	}
4252	>	return added;
4253	>	}
4254	>
4255	>	public int hashCode() {
4256	>	int h = 0;
4257	>	for (K e : this)
4258	>	h += e.hashCode();
4259	>	return h;
4260	>	}
4261	>
4262	>	public boolean equals(Object o) {
4263	>	Set<?> c;
4264	>	return ((o instanceof Set) &&
4265	>	((c = (Set<?>)o) == this ||
4266	>	(containsAll(c) && c.containsAll(this))));
4267	>	}
4268	>
4269	>	public Spliterator<K> spliterator() {
4270	>	Node<K,V>[] t;
4271	>	ConcurrentHashMap<K,V> m = map;
4272	>	long n = m.sumCount();
4273	>	int f = (t = m.table) == null ? 0 : t.length;
4274	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4275	>	}
4276	>
4277	>	public void forEach(Consumer<? super K> action) {
4278	>	if (action == null) throw new NullPointerException();
4279	>	Node<K,V>[] t;
4280	>	if ((t = map.table) != null) {
4281	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4282	>	for (Node<K,V> p; (p = it.advance()) != null; )
4283	>	action.accept((K)p.key);
4284	>	}
4285		}
4286		}
4287
4288	<	final class KeyIterator
4289	<	extends HashIterator
4290	<	implements Iterator<K>, Enumeration<K>
4291	<	{
4292	<	public final K next()        { return super.nextEntry().key; }
4293	<	public final K nextElement() { return super.nextEntry().key; }
4294	<	}
4295	<
4296	<	final class ValueIterator
4297	<	extends HashIterator
4298	<	implements Iterator<V>, Enumeration<V>
4299	<	{
4300	<	public final V next()        { return super.nextEntry().value; }
4301	<	public final V nextElement() { return super.nextEntry().value; }
4288	>	/**
4289	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4290	>	* values, in which additions are disabled. This class cannot be
4291	>	* directly instantiated. See {@link #values()}.
4292	>	*/
4293	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4294	>	implements Collection<V>, java.io.Serializable {
4295	>	private static final long serialVersionUID = 2249069246763182397L;
4296	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4297	>	public final boolean contains(Object o) {
4298	>	return map.containsValue(o);
4299	>	}
4300	>
4301	>	public final boolean remove(Object o) {
4302	>	if (o != null) {
4303	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4304	>	if (o.equals(it.next())) {
4305	>	it.remove();
4306	>	return true;
4307	>	}
4308	>	}
4309	>	}
4310	>	return false;
4311	>	}
4312	>
4313	>	public final Iterator<V> iterator() {
4314	>	ConcurrentHashMap<K,V> m = map;
4315	>	Node<K,V>[] t;
4316	>	int f = (t = m.table) == null ? 0 : t.length;
4317	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4318	>	}
4319	>
4320	>	public final boolean add(V e) {
4321	>	throw new UnsupportedOperationException();
4322	>	}
4323	>	public final boolean addAll(Collection<? extends V> c) {
4324	>	throw new UnsupportedOperationException();
4325	>	}
4326	>
4327	>	public Spliterator<V> spliterator() {
4328	>	Node<K,V>[] t;
4329	>	ConcurrentHashMap<K,V> m = map;
4330	>	long n = m.sumCount();
4331	>	int f = (t = m.table) == null ? 0 : t.length;
4332	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4333	>	}
4334	>
4335	>	public void forEach(Consumer<? super V> action) {
4336	>	if (action == null) throw new NullPointerException();
4337	>	Node<K,V>[] t;
4338	>	if ((t = map.table) != null) {
4339	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4340	>	for (Node<K,V> p; (p = it.advance()) != null; )
4341	>	action.accept(p.val);
4342	>	}
4343	>	}
4344		}
4345
4346		/**
4347	<	* Custom Entry class used by EntryIterator.next(), that relays
4348	<	* setValue changes to the underlying map.
4349	<	*/
4350	<	final class WriteThroughEntry
4351	<	extends AbstractMap.SimpleEntry<K,V>
4352	<	{
4353	<	WriteThroughEntry(K k, V v) {
4354	<	super(k,v);
4347	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4348	>	* entries.  This class cannot be directly instantiated. See
4349	>	* {@link #entrySet()}.
4350	>	*/
4351	>	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4352	>	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4353	>	private static final long serialVersionUID = 2249069246763182397L;
4354	>	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4355	>
4356	>	public boolean contains(Object o) {
4357	>	Object k, v, r; Map.Entry<?,?> e;
4358	>	return ((o instanceof Map.Entry) &&
4359	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4360	>	(r = map.get(k)) != null &&
4361	>	(v = e.getValue()) != null &&
4362	>	(v == r || v.equals(r)));
4363	>	}
4364	>
4365	>	public boolean remove(Object o) {
4366	>	Object k, v; Map.Entry<?,?> e;
4367	>	return ((o instanceof Map.Entry) &&
4368	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4369	>	(v = e.getValue()) != null &&
4370	>	map.remove(k, v));
4371		}
4372
4373		/**
4374	<	* Sets our entry's value and writes through to the map. The
1305	<	* value to return is somewhat arbitrary here. Since a
1306	<	* WriteThroughEntry does not necessarily track asynchronous
1307	<	* changes, the most recent "previous" value could be
1308	<	* different from what we return (or could even have been
1309	<	* removed in which case the put will re-establish). We do not
1310	<	* and cannot guarantee more.
4374	>	* @return an iterator over the entries of the backing map
4375		*/
4376	<	public V setValue(V value) {
4377	<	if (value == null) throw new NullPointerException();
4378	<	V v = super.setValue(value);
4379	<	ConcurrentHashMap.this.put(getKey(), value);
4380	<	return v;
4376	>	public Iterator<Map.Entry<K,V>> iterator() {
4377	>	ConcurrentHashMap<K,V> m = map;
4378	>	Node<K,V>[] t;
4379	>	int f = (t = m.table) == null ? 0 : t.length;
4380	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4381	>	}
4382	>
4383	>	public boolean add(Entry<K,V> e) {
4384	>	return map.internalPut(e.getKey(), e.getValue(), false) == null;
4385	>	}
4386	>
4387	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4388	>	boolean added = false;
4389	>	for (Entry<K,V> e : c) {
4390	>	if (add(e))
4391	>	added = true;
4392	>	}
4393	>	return added;
4394	>	}
4395	>
4396	>	public final int hashCode() {
4397	>	int h = 0;
4398	>	Node<K,V>[] t;
4399	>	if ((t = map.table) != null) {
4400	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4401	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4402	>	h += p.hashCode();
4403	>	}
4404	>	}
4405	>	return h;
4406	>	}
4407	>
4408	>	public final boolean equals(Object o) {
4409	>	Set<?> c;
4410	>	return ((o instanceof Set) &&
4411	>	((c = (Set<?>)o) == this ||
4412	>	(containsAll(c) && c.containsAll(this))));
4413	>	}
4414	>
4415	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4416	>	Node<K,V>[] t;
4417	>	ConcurrentHashMap<K,V> m = map;
4418	>	long n = m.sumCount();
4419	>	int f = (t = m.table) == null ? 0 : t.length;
4420	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4421	>	}
4422	>
4423	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4424	>	if (action == null) throw new NullPointerException();
4425	>	Node<K,V>[] t;
4426	>	if ((t = map.table) != null) {
4427	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4428	>	for (Node<K,V> p; (p = it.advance()) != null; )
4429	>	action.accept(new MapEntry<K,V>((K)p.key, p.val, map));
4430	>	}
4431		}
4432	+
4433		}
4434
4435	<	final class EntryIterator
4436	<	extends HashIterator
4437	<	implements Iterator<Entry<K,V>>
4438	<	{
4439	<	public Map.Entry<K,V> next() {
4440	<	HashEntry<K,V> e = super.nextEntry();
4441	<	return new WriteThroughEntry(e.key, e.value);
4435	>	// -------------------------------------------------------
4436	>
4437	>	/**
4438	>	* Base class for bulk tasks. Repeats some fields and code from
4439	>	* class Traverser, because we need to subclass CountedCompleter.
4440	>	*/
4441	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4442	>	Node<K,V>[] tab;        // same as Traverser
4443	>	Node<K,V> next;
4444	>	int index;
4445	>	int baseIndex;
4446	>	int baseLimit;
4447	>	final int baseSize;
4448	>	int batch;              // split control
4449	>
4450	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4451	>	super(par);
4452	>	this.batch = b;
4453	>	this.index = this.baseIndex = i;
4454	>	if ((this.tab = t) == null)
4455	>	this.baseSize = this.baseLimit = 0;
4456	>	else if (par == null)
4457	>	this.baseSize = this.baseLimit = t.length;
4458	>	else {
4459	>	this.baseLimit = f;
4460	>	this.baseSize = par.baseSize;
4461	>	}
4462	>	}
4463	>
4464	>	/**
4465	>	* Same as Traverser version
4466	>	*/
4467	>	final Node<K,V> advance() {
4468	>	Node<K,V> e;
4469	>	if ((e = next) != null)
4470	>	e = e.next;
4471	>	for (;;) {
4472	>	Node<K,V>[] t; int i, n; Object ek;
4473	>	if (e != null)
4474	>	return next = e;
4475	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4476	>	(n = t.length) <= (i = index) || i < 0)
4477	>	return next = null;
4478	>	if ((e = tabAt(t, index)) != null && e.hash < 0) {
4479	>	if ((ek = e.key) instanceof TreeBin)
4480	>	e = ((TreeBin<K,V>)ek).first;
4481	>	else {
4482	>	tab = (Node<K,V>[])ek;
4483	>	e = null;
4484	>	continue;
4485	>	}
4486	>	}
4487	>	if ((index += baseSize) >= n)
4488	>	index = ++baseIndex;
4489	>	}
4490		}
4491		}
4492
4493	<	final class KeySet extends AbstractSet<K> {
4494	<	public Iterator<K> iterator() {
4495	<	return new KeyIterator();
4493	>	/*
4494	>	* Task classes. Coded in a regular but ugly format/style to
4495	>	* simplify checks that each variant differs in the right way from
4496	>	* others. The null screenings exist because compilers cannot tell
4497	>	* that we've already null-checked task arguments, so we force
4498	>	* simplest hoisted bypass to help avoid convoluted traps.
4499	>	*/
4500	>
4501	>	static final class ForEachKeyTask<K,V>
4502	>	extends BulkTask<K,V,Void> {
4503	>	final Consumer<? super K> action;
4504	>	ForEachKeyTask
4505	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4506	>	Consumer<? super K> action) {
4507	>	super(p, b, i, f, t);
4508	>	this.action = action;
4509	>	}
4510	>	public final void compute() {
4511	>	final Consumer<? super K> action;
4512	>	if ((action = this.action) != null) {
4513	>	for (int i = baseIndex, f, h; batch > 0 &&
4514	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4515	>	addToPendingCount(1);
4516	>	new ForEachKeyTask<K,V>
4517	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4518	>	action).fork();
4519	>	}
4520	>	for (Node<K,V> p; (p = advance()) != null;)
4521	>	action.accept((K)p.key);
4522	>	propagateCompletion();
4523	>	}
4524		}
4525	<	public int size() {
4526	<	return ConcurrentHashMap.this.size();
4525	>	}
4526	>
4527	>	static final class ForEachValueTask<K,V>
4528	>	extends BulkTask<K,V,Void> {
4529	>	final Consumer<? super V> action;
4530	>	ForEachValueTask
4531	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4532	>	Consumer<? super V> action) {
4533	>	super(p, b, i, f, t);
4534	>	this.action = action;
4535	>	}
4536	>	public final void compute() {
4537	>	final Consumer<? super V> action;
4538	>	if ((action = this.action) != null) {
4539	>	for (int i = baseIndex, f, h; batch > 0 &&
4540	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4541	>	addToPendingCount(1);
4542	>	new ForEachValueTask<K,V>
4543	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4544	>	action).fork();
4545	>	}
4546	>	for (Node<K,V> p; (p = advance()) != null;)
4547	>	action.accept(p.val);
4548	>	propagateCompletion();
4549	>	}
4550		}
4551	<	public boolean isEmpty() {
4552	<	return ConcurrentHashMap.this.isEmpty();
4551	>	}
4552	>
4553	>	static final class ForEachEntryTask<K,V>
4554	>	extends BulkTask<K,V,Void> {
4555	>	final Consumer<? super Entry<K,V>> action;
4556	>	ForEachEntryTask
4557	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4558	>	Consumer<? super Entry<K,V>> action) {
4559	>	super(p, b, i, f, t);
4560	>	this.action = action;
4561	>	}
4562	>	public final void compute() {
4563	>	final Consumer<? super Entry<K,V>> action;
4564	>	if ((action = this.action) != null) {
4565	>	for (int i = baseIndex, f, h; batch > 0 &&
4566	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4567	>	addToPendingCount(1);
4568	>	new ForEachEntryTask<K,V>
4569	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4570	>	action).fork();
4571	>	}
4572	>	for (Node<K,V> p; (p = advance()) != null; )
4573	>	action.accept(p);
4574	>	propagateCompletion();
4575	>	}
4576		}
4577	<	public boolean contains(Object o) {
4578	<	return ConcurrentHashMap.this.containsKey(o);
4577	>	}
4578	>
4579	>	static final class ForEachMappingTask<K,V>
4580	>	extends BulkTask<K,V,Void> {
4581	>	final BiConsumer<? super K, ? super V> action;
4582	>	ForEachMappingTask
4583	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4584	>	BiConsumer<? super K,? super V> action) {
4585	>	super(p, b, i, f, t);
4586	>	this.action = action;
4587	>	}
4588	>	public final void compute() {
4589	>	final BiConsumer<? super K, ? super V> action;
4590	>	if ((action = this.action) != null) {
4591	>	for (int i = baseIndex, f, h; batch > 0 &&
4592	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4593	>	addToPendingCount(1);
4594	>	new ForEachMappingTask<K,V>
4595	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4596	>	action).fork();
4597	>	}
4598	>	for (Node<K,V> p; (p = advance()) != null; )
4599	>	action.accept((K)p.key, p.val);
4600	>	propagateCompletion();
4601	>	}
4602		}
4603	<	public boolean remove(Object o) {
4604	<	return ConcurrentHashMap.this.remove(o) != null;
4603	>	}
4604	>
4605	>	static final class ForEachTransformedKeyTask<K,V,U>
4606	>	extends BulkTask<K,V,Void> {
4607	>	final Function<? super K, ? extends U> transformer;
4608	>	final Consumer<? super U> action;
4609	>	ForEachTransformedKeyTask
4610	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4611	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
4612	>	super(p, b, i, f, t);
4613	>	this.transformer = transformer; this.action = action;
4614	>	}
4615	>	public final void compute() {
4616	>	final Function<? super K, ? extends U> transformer;
4617	>	final Consumer<? super U> action;
4618	>	if ((transformer = this.transformer) != null &&
4619	>	(action = this.action) != null) {
4620	>	for (int i = baseIndex, f, h; batch > 0 &&
4621	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4622	>	addToPendingCount(1);
4623	>	new ForEachTransformedKeyTask<K,V,U>
4624	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4625	>	transformer, action).fork();
4626	>	}
4627	>	for (Node<K,V> p; (p = advance()) != null; ) {
4628	>	U u;
4629	>	if ((u = transformer.apply((K)p.key)) != null)
4630	>	action.accept(u);
4631	>	}
4632	>	propagateCompletion();
4633	>	}
4634		}
4635	<	public void clear() {
4636	<	ConcurrentHashMap.this.clear();
4635	>	}
4636	>
4637	>	static final class ForEachTransformedValueTask<K,V,U>
4638	>	extends BulkTask<K,V,Void> {
4639	>	final Function<? super V, ? extends U> transformer;
4640	>	final Consumer<? super U> action;
4641	>	ForEachTransformedValueTask
4642	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4643	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
4644	>	super(p, b, i, f, t);
4645	>	this.transformer = transformer; this.action = action;
4646	>	}
4647	>	public final void compute() {
4648	>	final Function<? super V, ? extends U> transformer;
4649	>	final Consumer<? super U> action;
4650	>	if ((transformer = this.transformer) != null &&
4651	>	(action = this.action) != null) {
4652	>	for (int i = baseIndex, f, h; batch > 0 &&
4653	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4654	>	addToPendingCount(1);
4655	>	new ForEachTransformedValueTask<K,V,U>
4656	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4657	>	transformer, action).fork();
4658	>	}
4659	>	for (Node<K,V> p; (p = advance()) != null; ) {
4660	>	U u;
4661	>	if ((u = transformer.apply(p.val)) != null)
4662	>	action.accept(u);
4663	>	}
4664	>	propagateCompletion();
4665	>	}
4666		}
4667		}
4668
4669	<	final class Values extends AbstractCollection<V> {
4670	<	public Iterator<V> iterator() {
4671	<	return new ValueIterator();
4669	>	static final class ForEachTransformedEntryTask<K,V,U>
4670	>	extends BulkTask<K,V,Void> {
4671	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
4672	>	final Consumer<? super U> action;
4673	>	ForEachTransformedEntryTask
4674	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4675	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
4676	>	super(p, b, i, f, t);
4677	>	this.transformer = transformer; this.action = action;
4678	>	}
4679	>	public final void compute() {
4680	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
4681	>	final Consumer<? super U> action;
4682	>	if ((transformer = this.transformer) != null &&
4683	>	(action = this.action) != null) {
4684	>	for (int i = baseIndex, f, h; batch > 0 &&
4685	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4686	>	addToPendingCount(1);
4687	>	new ForEachTransformedEntryTask<K,V,U>
4688	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4689	>	transformer, action).fork();
4690	>	}
4691	>	for (Node<K,V> p; (p = advance()) != null; ) {
4692	>	U u;
4693	>	if ((u = transformer.apply(p)) != null)
4694	>	action.accept(u);
4695	>	}
4696	>	propagateCompletion();
4697	>	}
4698		}
4699	<	public int size() {
4700	<	return ConcurrentHashMap.this.size();
4699	>	}
4700	>
4701	>	static final class ForEachTransformedMappingTask<K,V,U>
4702	>	extends BulkTask<K,V,Void> {
4703	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
4704	>	final Consumer<? super U> action;
4705	>	ForEachTransformedMappingTask
4706	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4707	>	BiFunction<? super K, ? super V, ? extends U> transformer,
4708	>	Consumer<? super U> action) {
4709	>	super(p, b, i, f, t);
4710	>	this.transformer = transformer; this.action = action;
4711	>	}
4712	>	public final void compute() {
4713	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
4714	>	final Consumer<? super U> action;
4715	>	if ((transformer = this.transformer) != null &&
4716	>	(action = this.action) != null) {
4717	>	for (int i = baseIndex, f, h; batch > 0 &&
4718	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4719	>	addToPendingCount(1);
4720	>	new ForEachTransformedMappingTask<K,V,U>
4721	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4722	>	transformer, action).fork();
4723	>	}
4724	>	for (Node<K,V> p; (p = advance()) != null; ) {
4725	>	U u;
4726	>	if ((u = transformer.apply((K)p.key, p.val)) != null)
4727	>	action.accept(u);
4728	>	}
4729	>	propagateCompletion();
4730	>	}
4731	>	}
4732	>	}
4733	>
4734	>	static final class SearchKeysTask<K,V,U>
4735	>	extends BulkTask<K,V,U> {
4736	>	final Function<? super K, ? extends U> searchFunction;
4737	>	final AtomicReference<U> result;
4738	>	SearchKeysTask
4739	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4740	>	Function<? super K, ? extends U> searchFunction,
4741	>	AtomicReference<U> result) {
4742	>	super(p, b, i, f, t);
4743	>	this.searchFunction = searchFunction; this.result = result;
4744	>	}
4745	>	public final U getRawResult() { return result.get(); }
4746	>	public final void compute() {
4747	>	final Function<? super K, ? extends U> searchFunction;
4748	>	final AtomicReference<U> result;
4749	>	if ((searchFunction = this.searchFunction) != null &&
4750	>	(result = this.result) != null) {
4751	>	for (int i = baseIndex, f, h; batch > 0 &&
4752	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4753	>	if (result.get() != null)
4754	>	return;
4755	>	addToPendingCount(1);
4756	>	new SearchKeysTask<K,V,U>
4757	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4758	>	searchFunction, result).fork();
4759	>	}
4760	>	while (result.get() == null) {
4761	>	U u;
4762	>	Node<K,V> p;
4763	>	if ((p = advance()) == null) {
4764	>	propagateCompletion();
4765	>	break;
4766	>	}
4767	>	if ((u = searchFunction.apply((K)p.key)) != null) {
4768	>	if (result.compareAndSet(null, u))
4769	>	quietlyCompleteRoot();
4770	>	break;
4771	>	}
4772	>	}
4773	>	}
4774		}
4775	<	public boolean isEmpty() {
4776	<	return ConcurrentHashMap.this.isEmpty();
4775	>	}
4776	>
4777	>	static final class SearchValuesTask<K,V,U>
4778	>	extends BulkTask<K,V,U> {
4779	>	final Function<? super V, ? extends U> searchFunction;
4780	>	final AtomicReference<U> result;
4781	>	SearchValuesTask
4782	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4783	>	Function<? super V, ? extends U> searchFunction,
4784	>	AtomicReference<U> result) {
4785	>	super(p, b, i, f, t);
4786	>	this.searchFunction = searchFunction; this.result = result;
4787	>	}
4788	>	public final U getRawResult() { return result.get(); }
4789	>	public final void compute() {
4790	>	final Function<? super V, ? extends U> searchFunction;
4791	>	final AtomicReference<U> result;
4792	>	if ((searchFunction = this.searchFunction) != null &&
4793	>	(result = this.result) != null) {
4794	>	for (int i = baseIndex, f, h; batch > 0 &&
4795	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4796	>	if (result.get() != null)
4797	>	return;
4798	>	addToPendingCount(1);
4799	>	new SearchValuesTask<K,V,U>
4800	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4801	>	searchFunction, result).fork();
4802	>	}
4803	>	while (result.get() == null) {
4804	>	U u;
4805	>	Node<K,V> p;
4806	>	if ((p = advance()) == null) {
4807	>	propagateCompletion();
4808	>	break;
4809	>	}
4810	>	if ((u = searchFunction.apply(p.val)) != null) {
4811	>	if (result.compareAndSet(null, u))
4812	>	quietlyCompleteRoot();
4813	>	break;
4814	>	}
4815	>	}
4816	>	}
4817		}
4818	<	public boolean contains(Object o) {
4819	<	return ConcurrentHashMap.this.containsValue(o);
4818	>	}
4819	>
4820	>	static final class SearchEntriesTask<K,V,U>
4821	>	extends BulkTask<K,V,U> {
4822	>	final Function<Entry<K,V>, ? extends U> searchFunction;
4823	>	final AtomicReference<U> result;
4824	>	SearchEntriesTask
4825	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4826	>	Function<Entry<K,V>, ? extends U> searchFunction,
4827	>	AtomicReference<U> result) {
4828	>	super(p, b, i, f, t);
4829	>	this.searchFunction = searchFunction; this.result = result;
4830	>	}
4831	>	public final U getRawResult() { return result.get(); }
4832	>	public final void compute() {
4833	>	final Function<Entry<K,V>, ? extends U> searchFunction;
4834	>	final AtomicReference<U> result;
4835	>	if ((searchFunction = this.searchFunction) != null &&
4836	>	(result = this.result) != null) {
4837	>	for (int i = baseIndex, f, h; batch > 0 &&
4838	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4839	>	if (result.get() != null)
4840	>	return;
4841	>	addToPendingCount(1);
4842	>	new SearchEntriesTask<K,V,U>
4843	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4844	>	searchFunction, result).fork();
4845	>	}
4846	>	while (result.get() == null) {
4847	>	U u;
4848	>	Node<K,V> p;
4849	>	if ((p = advance()) == null) {
4850	>	propagateCompletion();
4851	>	break;
4852	>	}
4853	>	if ((u = searchFunction.apply(p)) != null) {
4854	>	if (result.compareAndSet(null, u))
4855	>	quietlyCompleteRoot();
4856	>	return;
4857	>	}
4858	>	}
4859	>	}
4860		}
4861	<	public void clear() {
4862	<	ConcurrentHashMap.this.clear();
4861	>	}
4862	>
4863	>	static final class SearchMappingsTask<K,V,U>
4864	>	extends BulkTask<K,V,U> {
4865	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
4866	>	final AtomicReference<U> result;
4867	>	SearchMappingsTask
4868	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4869	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
4870	>	AtomicReference<U> result) {
4871	>	super(p, b, i, f, t);
4872	>	this.searchFunction = searchFunction; this.result = result;
4873	>	}
4874	>	public final U getRawResult() { return result.get(); }
4875	>	public final void compute() {
4876	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
4877	>	final AtomicReference<U> result;
4878	>	if ((searchFunction = this.searchFunction) != null &&
4879	>	(result = this.result) != null) {
4880	>	for (int i = baseIndex, f, h; batch > 0 &&
4881	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4882	>	if (result.get() != null)
4883	>	return;
4884	>	addToPendingCount(1);
4885	>	new SearchMappingsTask<K,V,U>
4886	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4887	>	searchFunction, result).fork();
4888	>	}
4889	>	while (result.get() == null) {
4890	>	U u;
4891	>	Node<K,V> p;
4892	>	if ((p = advance()) == null) {
4893	>	propagateCompletion();
4894	>	break;
4895	>	}
4896	>	if ((u = searchFunction.apply((K)p.key, p.val)) != null) {
4897	>	if (result.compareAndSet(null, u))
4898	>	quietlyCompleteRoot();
4899	>	break;
4900	>	}
4901	>	}
4902	>	}
4903		}
4904		}
4905
4906	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4907	<	public Iterator<Map.Entry<K,V>> iterator() {
4908	<	return new EntryIterator();
4906	>	static final class ReduceKeysTask<K,V>
4907	>	extends BulkTask<K,V,K> {
4908	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
4909	>	K result;
4910	>	ReduceKeysTask<K,V> rights, nextRight;
4911	>	ReduceKeysTask
4912	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4913	>	ReduceKeysTask<K,V> nextRight,
4914	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
4915	>	super(p, b, i, f, t); this.nextRight = nextRight;
4916	>	this.reducer = reducer;
4917	>	}
4918	>	public final K getRawResult() { return result; }
4919	>	public final void compute() {
4920	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
4921	>	if ((reducer = this.reducer) != null) {
4922	>	for (int i = baseIndex, f, h; batch > 0 &&
4923	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4924	>	addToPendingCount(1);
4925	>	(rights = new ReduceKeysTask<K,V>
4926	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4927	>	rights, reducer)).fork();
4928	>	}
4929	>	K r = null;
4930	>	for (Node<K,V> p; (p = advance()) != null; ) {
4931	>	K u = (K)p.key;
4932	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
4933	>	}
4934	>	result = r;
4935	>	CountedCompleter<?> c;
4936	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
4937	>	ReduceKeysTask<K,V>
4938	>	t = (ReduceKeysTask<K,V>)c,
4939	>	s = t.rights;
4940	>	while (s != null) {
4941	>	K tr, sr;
4942	>	if ((sr = s.result) != null)
4943	>	t.result = (((tr = t.result) == null) ? sr :
4944	>	reducer.apply(tr, sr));
4945	>	s = t.rights = s.nextRight;
4946	>	}
4947	>	}
4948	>	}
4949		}
4950	<	public boolean contains(Object o) {
4951	<	if (!(o instanceof Map.Entry))
4952	<	return false;
4953	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4954	<	V v = ConcurrentHashMap.this.get(e.getKey());
4955	<	return v != null && v.equals(e.getValue());
4950	>	}
4951	>
4952	>	static final class ReduceValuesTask<K,V>
4953	>	extends BulkTask<K,V,V> {
4954	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
4955	>	V result;
4956	>	ReduceValuesTask<K,V> rights, nextRight;
4957	>	ReduceValuesTask
4958	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4959	>	ReduceValuesTask<K,V> nextRight,
4960	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4961	>	super(p, b, i, f, t); this.nextRight = nextRight;
4962	>	this.reducer = reducer;
4963	>	}
4964	>	public final V getRawResult() { return result; }
4965	>	public final void compute() {
4966	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
4967	>	if ((reducer = this.reducer) != null) {
4968	>	for (int i = baseIndex, f, h; batch > 0 &&
4969	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4970	>	addToPendingCount(1);
4971	>	(rights = new ReduceValuesTask<K,V>
4972	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4973	>	rights, reducer)).fork();
4974	>	}
4975	>	V r = null;
4976	>	for (Node<K,V> p; (p = advance()) != null; ) {
4977	>	V v = p.val;
4978	>	r = (r == null) ? v : reducer.apply(r, v);
4979	>	}
4980	>	result = r;
4981	>	CountedCompleter<?> c;
4982	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
4983	>	ReduceValuesTask<K,V>
4984	>	t = (ReduceValuesTask<K,V>)c,
4985	>	s = t.rights;
4986	>	while (s != null) {
4987	>	V tr, sr;
4988	>	if ((sr = s.result) != null)
4989	>	t.result = (((tr = t.result) == null) ? sr :
4990	>	reducer.apply(tr, sr));
4991	>	s = t.rights = s.nextRight;
4992	>	}
4993	>	}
4994	>	}
4995		}
4996	<	public boolean remove(Object o) {
4997	<	if (!(o instanceof Map.Entry))
4998	<	return false;
4999	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
5000	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
4996	>	}
4997	>
4998	>	static final class ReduceEntriesTask<K,V>
4999	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5000	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5001	>	Map.Entry<K,V> result;
5002	>	ReduceEntriesTask<K,V> rights, nextRight;
5003	>	ReduceEntriesTask
5004	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5005	>	ReduceEntriesTask<K,V> nextRight,
5006	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5007	>	super(p, b, i, f, t); this.nextRight = nextRight;
5008	>	this.reducer = reducer;
5009	>	}
5010	>	public final Map.Entry<K,V> getRawResult() { return result; }
5011	>	public final void compute() {
5012	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5013	>	if ((reducer = this.reducer) != null) {
5014	>	for (int i = baseIndex, f, h; batch > 0 &&
5015	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5016	>	addToPendingCount(1);
5017	>	(rights = new ReduceEntriesTask<K,V>
5018	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5019	>	rights, reducer)).fork();
5020	>	}
5021	>	Map.Entry<K,V> r = null;
5022	>	for (Node<K,V> p; (p = advance()) != null; )
5023	>	r = (r == null) ? p : reducer.apply(r, p);
5024	>	result = r;
5025	>	CountedCompleter<?> c;
5026	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5027	>	ReduceEntriesTask<K,V>
5028	>	t = (ReduceEntriesTask<K,V>)c,
5029	>	s = t.rights;
5030	>	while (s != null) {
5031	>	Map.Entry<K,V> tr, sr;
5032	>	if ((sr = s.result) != null)
5033	>	t.result = (((tr = t.result) == null) ? sr :
5034	>	reducer.apply(tr, sr));
5035	>	s = t.rights = s.nextRight;
5036	>	}
5037	>	}
5038	>	}
5039		}
5040	<	public int size() {
5041	<	return ConcurrentHashMap.this.size();
5040	>	}
5041	>
5042	>	static final class MapReduceKeysTask<K,V,U>
5043	>	extends BulkTask<K,V,U> {
5044	>	final Function<? super K, ? extends U> transformer;
5045	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5046	>	U result;
5047	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5048	>	MapReduceKeysTask
5049	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5050	>	MapReduceKeysTask<K,V,U> nextRight,
5051	>	Function<? super K, ? extends U> transformer,
5052	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5053	>	super(p, b, i, f, t); this.nextRight = nextRight;
5054	>	this.transformer = transformer;
5055	>	this.reducer = reducer;
5056	>	}
5057	>	public final U getRawResult() { return result; }
5058	>	public final void compute() {
5059	>	final Function<? super K, ? extends U> transformer;
5060	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5061	>	if ((transformer = this.transformer) != null &&
5062	>	(reducer = this.reducer) != null) {
5063	>	for (int i = baseIndex, f, h; batch > 0 &&
5064	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5065	>	addToPendingCount(1);
5066	>	(rights = new MapReduceKeysTask<K,V,U>
5067	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5068	>	rights, transformer, reducer)).fork();
5069	>	}
5070	>	U r = null;
5071	>	for (Node<K,V> p; (p = advance()) != null; ) {
5072	>	U u;
5073	>	if ((u = transformer.apply((K)p.key)) != null)
5074	>	r = (r == null) ? u : reducer.apply(r, u);
5075	>	}
5076	>	result = r;
5077	>	CountedCompleter<?> c;
5078	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5079	>	MapReduceKeysTask<K,V,U>
5080	>	t = (MapReduceKeysTask<K,V,U>)c,
5081	>	s = t.rights;
5082	>	while (s != null) {
5083	>	U tr, sr;
5084	>	if ((sr = s.result) != null)
5085	>	t.result = (((tr = t.result) == null) ? sr :
5086	>	reducer.apply(tr, sr));
5087	>	s = t.rights = s.nextRight;
5088	>	}
5089	>	}
5090	>	}
5091		}
5092	<	public boolean isEmpty() {
5093	<	return ConcurrentHashMap.this.isEmpty();
5092	>	}
5093	>
5094	>	static final class MapReduceValuesTask<K,V,U>
5095	>	extends BulkTask<K,V,U> {
5096	>	final Function<? super V, ? extends U> transformer;
5097	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5098	>	U result;
5099	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5100	>	MapReduceValuesTask
5101	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5102	>	MapReduceValuesTask<K,V,U> nextRight,
5103	>	Function<? super V, ? extends U> transformer,
5104	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5105	>	super(p, b, i, f, t); this.nextRight = nextRight;
5106	>	this.transformer = transformer;
5107	>	this.reducer = reducer;
5108	>	}
5109	>	public final U getRawResult() { return result; }
5110	>	public final void compute() {
5111	>	final Function<? super V, ? extends U> transformer;
5112	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5113	>	if ((transformer = this.transformer) != null &&
5114	>	(reducer = this.reducer) != null) {
5115	>	for (int i = baseIndex, f, h; batch > 0 &&
5116	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5117	>	addToPendingCount(1);
5118	>	(rights = new MapReduceValuesTask<K,V,U>
5119	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5120	>	rights, transformer, reducer)).fork();
5121	>	}
5122	>	U r = null;
5123	>	for (Node<K,V> p; (p = advance()) != null; ) {
5124	>	U u;
5125	>	if ((u = transformer.apply(p.val)) != null)
5126	>	r = (r == null) ? u : reducer.apply(r, u);
5127	>	}
5128	>	result = r;
5129	>	CountedCompleter<?> c;
5130	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5131	>	MapReduceValuesTask<K,V,U>
5132	>	t = (MapReduceValuesTask<K,V,U>)c,
5133	>	s = t.rights;
5134	>	while (s != null) {
5135	>	U tr, sr;
5136	>	if ((sr = s.result) != null)
5137	>	t.result = (((tr = t.result) == null) ? sr :
5138	>	reducer.apply(tr, sr));
5139	>	s = t.rights = s.nextRight;
5140	>	}
5141	>	}
5142	>	}
5143		}
5144	<	public void clear() {
5145	<	ConcurrentHashMap.this.clear();
5144	>	}
5145	>
5146	>	static final class MapReduceEntriesTask<K,V,U>
5147	>	extends BulkTask<K,V,U> {
5148	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5149	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5150	>	U result;
5151	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5152	>	MapReduceEntriesTask
5153	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5154	>	MapReduceEntriesTask<K,V,U> nextRight,
5155	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5156	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5157	>	super(p, b, i, f, t); this.nextRight = nextRight;
5158	>	this.transformer = transformer;
5159	>	this.reducer = reducer;
5160	>	}
5161	>	public final U getRawResult() { return result; }
5162	>	public final void compute() {
5163	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5164	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5165	>	if ((transformer = this.transformer) != null &&
5166	>	(reducer = this.reducer) != null) {
5167	>	for (int i = baseIndex, f, h; batch > 0 &&
5168	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5169	>	addToPendingCount(1);
5170	>	(rights = new MapReduceEntriesTask<K,V,U>
5171	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5172	>	rights, transformer, reducer)).fork();
5173	>	}
5174	>	U r = null;
5175	>	for (Node<K,V> p; (p = advance()) != null; ) {
5176	>	U u;
5177	>	if ((u = transformer.apply(p)) != null)
5178	>	r = (r == null) ? u : reducer.apply(r, u);
5179	>	}
5180	>	result = r;
5181	>	CountedCompleter<?> c;
5182	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5183	>	MapReduceEntriesTask<K,V,U>
5184	>	t = (MapReduceEntriesTask<K,V,U>)c,
5185	>	s = t.rights;
5186	>	while (s != null) {
5187	>	U tr, sr;
5188	>	if ((sr = s.result) != null)
5189	>	t.result = (((tr = t.result) == null) ? sr :
5190	>	reducer.apply(tr, sr));
5191	>	s = t.rights = s.nextRight;
5192	>	}
5193	>	}
5194	>	}
5195		}
5196		}
5197
5198	<	/* ---------------- Serialization Support -------------- */
5198	>	static final class MapReduceMappingsTask<K,V,U>
5199	>	extends BulkTask<K,V,U> {
5200	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5201	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5202	>	U result;
5203	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5204	>	MapReduceMappingsTask
5205	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5206	>	MapReduceMappingsTask<K,V,U> nextRight,
5207	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5208	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5209	>	super(p, b, i, f, t); this.nextRight = nextRight;
5210	>	this.transformer = transformer;
5211	>	this.reducer = reducer;
5212	>	}
5213	>	public final U getRawResult() { return result; }
5214	>	public final void compute() {
5215	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5216	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5217	>	if ((transformer = this.transformer) != null &&
5218	>	(reducer = this.reducer) != null) {
5219	>	for (int i = baseIndex, f, h; batch > 0 &&
5220	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5221	>	addToPendingCount(1);
5222	>	(rights = new MapReduceMappingsTask<K,V,U>
5223	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5224	>	rights, transformer, reducer)).fork();
5225	>	}
5226	>	U r = null;
5227	>	for (Node<K,V> p; (p = advance()) != null; ) {
5228	>	U u;
5229	>	if ((u = transformer.apply((K)p.key, p.val)) != null)
5230	>	r = (r == null) ? u : reducer.apply(r, u);
5231	>	}
5232	>	result = r;
5233	>	CountedCompleter<?> c;
5234	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5235	>	MapReduceMappingsTask<K,V,U>
5236	>	t = (MapReduceMappingsTask<K,V,U>)c,
5237	>	s = t.rights;
5238	>	while (s != null) {
5239	>	U tr, sr;
5240	>	if ((sr = s.result) != null)
5241	>	t.result = (((tr = t.result) == null) ? sr :
5242	>	reducer.apply(tr, sr));
5243	>	s = t.rights = s.nextRight;
5244	>	}
5245	>	}
5246	>	}
5247	>	}
5248	>	}
5249
5250	<	/**
5251	<	* Saves the state of the <tt>ConcurrentHashMap</tt> instance to a
5252	<	* stream (i.e., serializes it).
5253	<	* @param s the stream
5254	<	* @serialData
5255	<	* the key (Object) and value (Object)
5256	<	* for each key-value mapping, followed by a null pair.
5257	<	* The key-value mappings are emitted in no particular order.
5258	<	*/
5259	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException {
5260	<	// force all segments for serialization compatibility
5261	<	for (int k = 0; k < segments.length; ++k)
5262	<	ensureSegment(k);
5263	<	s.defaultWriteObject();
5264	<
5265	<	final Segment<K,V>[] segments = this.segments;
5266	<	for (int k = 0; k < segments.length; ++k) {
5267	<	Segment<K,V> seg = segmentAt(segments, k);
5268	<	seg.lock();
5269	<	try {
5270	<	HashEntry<K,V>[] tab = seg.table;
5271	<	for (int i = 0; i < tab.length; ++i) {
5272	<	HashEntry<K,V> e;
5273	<	for (e = entryAt(tab, i); e != null; e = e.next) {
5274	<	s.writeObject(e.key);
5275	<	s.writeObject(e.value);
5250	>	static final class MapReduceKeysToDoubleTask<K,V>
5251	>	extends BulkTask<K,V,Double> {
5252	>	final ToDoubleFunction<? super K> transformer;
5253	>	final DoubleBinaryOperator reducer;
5254	>	final double basis;
5255	>	double result;
5256	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5257	>	MapReduceKeysToDoubleTask
5258	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5259	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5260	>	ToDoubleFunction<? super K> transformer,
5261	>	double basis,
5262	>	DoubleBinaryOperator reducer) {
5263	>	super(p, b, i, f, t); this.nextRight = nextRight;
5264	>	this.transformer = transformer;
5265	>	this.basis = basis; this.reducer = reducer;
5266	>	}
5267	>	public final Double getRawResult() { return result; }
5268	>	public final void compute() {
5269	>	final ToDoubleFunction<? super K> transformer;
5270	>	final DoubleBinaryOperator reducer;
5271	>	if ((transformer = this.transformer) != null &&
5272	>	(reducer = this.reducer) != null) {
5273	>	double r = this.basis;
5274	>	for (int i = baseIndex, f, h; batch > 0 &&
5275	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5276	>	addToPendingCount(1);
5277	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5278	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5279	>	rights, transformer, r, reducer)).fork();
5280	>	}
5281	>	for (Node<K,V> p; (p = advance()) != null; )
5282	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble((K)p.key));
5283	>	result = r;
5284	>	CountedCompleter<?> c;
5285	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5286	>	MapReduceKeysToDoubleTask<K,V>
5287	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5288	>	s = t.rights;
5289	>	while (s != null) {
5290	>	t.result = reducer.applyAsDouble(t.result, s.result);
5291	>	s = t.rights = s.nextRight;
5292		}
5293		}
1427	–	} finally {
1428	–	seg.unlock();
5294		}
5295		}
1431	–	s.writeObject(null);
1432	–	s.writeObject(null);
5296		}
5297
5298	<	/**
5299	<	* Reconstitutes the <tt>ConcurrentHashMap</tt> instance from a
5300	<	* stream (i.e., deserializes it).
5301	<	* @param s the stream
5302	<	*/
5303	<	@SuppressWarnings("unchecked")
5304	<	private void readObject(java.io.ObjectInputStream s)
5305	<	throws IOException, ClassNotFoundException {
5306	<	s.defaultReadObject();
5298	>	static final class MapReduceValuesToDoubleTask<K,V>
5299	>	extends BulkTask<K,V,Double> {
5300	>	final ToDoubleFunction<? super V> transformer;
5301	>	final DoubleBinaryOperator reducer;
5302	>	final double basis;
5303	>	double result;
5304	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5305	>	MapReduceValuesToDoubleTask
5306	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5307	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5308	>	ToDoubleFunction<? super V> transformer,
5309	>	double basis,
5310	>	DoubleBinaryOperator reducer) {
5311	>	super(p, b, i, f, t); this.nextRight = nextRight;
5312	>	this.transformer = transformer;
5313	>	this.basis = basis; this.reducer = reducer;
5314	>	}
5315	>	public final Double getRawResult() { return result; }
5316	>	public final void compute() {
5317	>	final ToDoubleFunction<? super V> transformer;
5318	>	final DoubleBinaryOperator reducer;
5319	>	if ((transformer = this.transformer) != null &&
5320	>	(reducer = this.reducer) != null) {
5321	>	double r = this.basis;
5322	>	for (int i = baseIndex, f, h; batch > 0 &&
5323	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5324	>	addToPendingCount(1);
5325	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5326	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5327	>	rights, transformer, r, reducer)).fork();
5328	>	}
5329	>	for (Node<K,V> p; (p = advance()) != null; )
5330	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5331	>	result = r;
5332	>	CountedCompleter<?> c;
5333	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5334	>	MapReduceValuesToDoubleTask<K,V>
5335	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5336	>	s = t.rights;
5337	>	while (s != null) {
5338	>	t.result = reducer.applyAsDouble(t.result, s.result);
5339	>	s = t.rights = s.nextRight;
5340	>	}
5341	>	}
5342	>	}
5343	>	}
5344	>	}
5345
5346	<	// Re-initialize segments to be minimally sized, and let grow.
5347	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
5348	<	final Segment<K,V>[] segments = this.segments;
5349	<	for (int k = 0; k < segments.length; ++k) {
5350	<	Segment<K,V> seg = segments[k];
5351	<	if (seg != null) {
5352	<	seg.threshold = (int)(cap * seg.loadFactor);
5353	<	seg.table = (HashEntry<K,V>[]) new HashEntry[cap];
5346	>	static final class MapReduceEntriesToDoubleTask<K,V>
5347	>	extends BulkTask<K,V,Double> {
5348	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5349	>	final DoubleBinaryOperator reducer;
5350	>	final double basis;
5351	>	double result;
5352	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5353	>	MapReduceEntriesToDoubleTask
5354	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5355	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5356	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5357	>	double basis,
5358	>	DoubleBinaryOperator reducer) {
5359	>	super(p, b, i, f, t); this.nextRight = nextRight;
5360	>	this.transformer = transformer;
5361	>	this.basis = basis; this.reducer = reducer;
5362	>	}
5363	>	public final Double getRawResult() { return result; }
5364	>	public final void compute() {
5365	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5366	>	final DoubleBinaryOperator reducer;
5367	>	if ((transformer = this.transformer) != null &&
5368	>	(reducer = this.reducer) != null) {
5369	>	double r = this.basis;
5370	>	for (int i = baseIndex, f, h; batch > 0 &&
5371	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5372	>	addToPendingCount(1);
5373	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5374	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5375	>	rights, transformer, r, reducer)).fork();
5376	>	}
5377	>	for (Node<K,V> p; (p = advance()) != null; )
5378	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5379	>	result = r;
5380	>	CountedCompleter<?> c;
5381	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5382	>	MapReduceEntriesToDoubleTask<K,V>
5383	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5384	>	s = t.rights;
5385	>	while (s != null) {
5386	>	t.result = reducer.applyAsDouble(t.result, s.result);
5387	>	s = t.rights = s.nextRight;
5388	>	}
5389	>	}
5390		}
5391		}
5392	+	}
5393
5394	<	// Read the keys and values, and put the mappings in the table
5395	<	for (;;) {
5396	<	K key = (K) s.readObject();
5397	<	V value = (V) s.readObject();
5398	<	if (key == null)
5399	<	break;
5400	<	put(key, value);
5394	>	static final class MapReduceMappingsToDoubleTask<K,V>
5395	>	extends BulkTask<K,V,Double> {
5396	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5397	>	final DoubleBinaryOperator reducer;
5398	>	final double basis;
5399	>	double result;
5400	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5401	>	MapReduceMappingsToDoubleTask
5402	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5403	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5404	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5405	>	double basis,
5406	>	DoubleBinaryOperator reducer) {
5407	>	super(p, b, i, f, t); this.nextRight = nextRight;
5408	>	this.transformer = transformer;
5409	>	this.basis = basis; this.reducer = reducer;
5410	>	}
5411	>	public final Double getRawResult() { return result; }
5412	>	public final void compute() {
5413	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5414	>	final DoubleBinaryOperator reducer;
5415	>	if ((transformer = this.transformer) != null &&
5416	>	(reducer = this.reducer) != null) {
5417	>	double r = this.basis;
5418	>	for (int i = baseIndex, f, h; batch > 0 &&
5419	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5420	>	addToPendingCount(1);
5421	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5422	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5423	>	rights, transformer, r, reducer)).fork();
5424	>	}
5425	>	for (Node<K,V> p; (p = advance()) != null; )
5426	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble((K)p.key, p.val));
5427	>	result = r;
5428	>	CountedCompleter<?> c;
5429	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5430	>	MapReduceMappingsToDoubleTask<K,V>
5431	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5432	>	s = t.rights;
5433	>	while (s != null) {
5434	>	t.result = reducer.applyAsDouble(t.result, s.result);
5435	>	s = t.rights = s.nextRight;
5436	>	}
5437	>	}
5438	>	}
5439	>	}
5440	>	}
5441	>
5442	>	static final class MapReduceKeysToLongTask<K,V>
5443	>	extends BulkTask<K,V,Long> {
5444	>	final ToLongFunction<? super K> transformer;
5445	>	final LongBinaryOperator reducer;
5446	>	final long basis;
5447	>	long result;
5448	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5449	>	MapReduceKeysToLongTask
5450	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5451	>	MapReduceKeysToLongTask<K,V> nextRight,
5452	>	ToLongFunction<? super K> transformer,
5453	>	long basis,
5454	>	LongBinaryOperator reducer) {
5455	>	super(p, b, i, f, t); this.nextRight = nextRight;
5456	>	this.transformer = transformer;
5457	>	this.basis = basis; this.reducer = reducer;
5458	>	}
5459	>	public final Long getRawResult() { return result; }
5460	>	public final void compute() {
5461	>	final ToLongFunction<? super K> transformer;
5462	>	final LongBinaryOperator reducer;
5463	>	if ((transformer = this.transformer) != null &&
5464	>	(reducer = this.reducer) != null) {
5465	>	long r = this.basis;
5466	>	for (int i = baseIndex, f, h; batch > 0 &&
5467	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5468	>	addToPendingCount(1);
5469	>	(rights = new MapReduceKeysToLongTask<K,V>
5470	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5471	>	rights, transformer, r, reducer)).fork();
5472	>	}
5473	>	for (Node<K,V> p; (p = advance()) != null; )
5474	>	r = reducer.applyAsLong(r, transformer.applyAsLong((K)p.key));
5475	>	result = r;
5476	>	CountedCompleter<?> c;
5477	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5478	>	MapReduceKeysToLongTask<K,V>
5479	>	t = (MapReduceKeysToLongTask<K,V>)c,
5480	>	s = t.rights;
5481	>	while (s != null) {
5482	>	t.result = reducer.applyAsLong(t.result, s.result);
5483	>	s = t.rights = s.nextRight;
5484	>	}
5485	>	}
5486	>	}
5487	>	}
5488	>	}
5489	>
5490	>	static final class MapReduceValuesToLongTask<K,V>
5491	>	extends BulkTask<K,V,Long> {
5492	>	final ToLongFunction<? super V> transformer;
5493	>	final LongBinaryOperator reducer;
5494	>	final long basis;
5495	>	long result;
5496	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5497	>	MapReduceValuesToLongTask
5498	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5499	>	MapReduceValuesToLongTask<K,V> nextRight,
5500	>	ToLongFunction<? super V> transformer,
5501	>	long basis,
5502	>	LongBinaryOperator reducer) {
5503	>	super(p, b, i, f, t); this.nextRight = nextRight;
5504	>	this.transformer = transformer;
5505	>	this.basis = basis; this.reducer = reducer;
5506	>	}
5507	>	public final Long getRawResult() { return result; }
5508	>	public final void compute() {
5509	>	final ToLongFunction<? super V> transformer;
5510	>	final LongBinaryOperator reducer;
5511	>	if ((transformer = this.transformer) != null &&
5512	>	(reducer = this.reducer) != null) {
5513	>	long r = this.basis;
5514	>	for (int i = baseIndex, f, h; batch > 0 &&
5515	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5516	>	addToPendingCount(1);
5517	>	(rights = new MapReduceValuesToLongTask<K,V>
5518	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5519	>	rights, transformer, r, reducer)).fork();
5520	>	}
5521	>	for (Node<K,V> p; (p = advance()) != null; )
5522	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
5523	>	result = r;
5524	>	CountedCompleter<?> c;
5525	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5526	>	MapReduceValuesToLongTask<K,V>
5527	>	t = (MapReduceValuesToLongTask<K,V>)c,
5528	>	s = t.rights;
5529	>	while (s != null) {
5530	>	t.result = reducer.applyAsLong(t.result, s.result);
5531	>	s = t.rights = s.nextRight;
5532	>	}
5533	>	}
5534	>	}
5535	>	}
5536	>	}
5537	>
5538	>	static final class MapReduceEntriesToLongTask<K,V>
5539	>	extends BulkTask<K,V,Long> {
5540	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5541	>	final LongBinaryOperator reducer;
5542	>	final long basis;
5543	>	long result;
5544	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
5545	>	MapReduceEntriesToLongTask
5546	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5547	>	MapReduceEntriesToLongTask<K,V> nextRight,
5548	>	ToLongFunction<Map.Entry<K,V>> transformer,
5549	>	long basis,
5550	>	LongBinaryOperator reducer) {
5551	>	super(p, b, i, f, t); this.nextRight = nextRight;
5552	>	this.transformer = transformer;
5553	>	this.basis = basis; this.reducer = reducer;
5554	>	}
5555	>	public final Long getRawResult() { return result; }
5556	>	public final void compute() {
5557	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5558	>	final LongBinaryOperator reducer;
5559	>	if ((transformer = this.transformer) != null &&
5560	>	(reducer = this.reducer) != null) {
5561	>	long r = this.basis;
5562	>	for (int i = baseIndex, f, h; batch > 0 &&
5563	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5564	>	addToPendingCount(1);
5565	>	(rights = new MapReduceEntriesToLongTask<K,V>
5566	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5567	>	rights, transformer, r, reducer)).fork();
5568	>	}
5569	>	for (Node<K,V> p; (p = advance()) != null; )
5570	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
5571	>	result = r;
5572	>	CountedCompleter<?> c;
5573	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5574	>	MapReduceEntriesToLongTask<K,V>
5575	>	t = (MapReduceEntriesToLongTask<K,V>)c,
5576	>	s = t.rights;
5577	>	while (s != null) {
5578	>	t.result = reducer.applyAsLong(t.result, s.result);
5579	>	s = t.rights = s.nextRight;
5580	>	}
5581	>	}
5582	>	}
5583	>	}
5584	>	}
5585	>
5586	>	static final class MapReduceMappingsToLongTask<K,V>
5587	>	extends BulkTask<K,V,Long> {
5588	>	final ToLongBiFunction<? super K, ? super V> transformer;
5589	>	final LongBinaryOperator reducer;
5590	>	final long basis;
5591	>	long result;
5592	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
5593	>	MapReduceMappingsToLongTask
5594	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5595	>	MapReduceMappingsToLongTask<K,V> nextRight,
5596	>	ToLongBiFunction<? super K, ? super V> transformer,
5597	>	long basis,
5598	>	LongBinaryOperator reducer) {
5599	>	super(p, b, i, f, t); this.nextRight = nextRight;
5600	>	this.transformer = transformer;
5601	>	this.basis = basis; this.reducer = reducer;
5602	>	}
5603	>	public final Long getRawResult() { return result; }
5604	>	public final void compute() {
5605	>	final ToLongBiFunction<? super K, ? super V> transformer;
5606	>	final LongBinaryOperator reducer;
5607	>	if ((transformer = this.transformer) != null &&
5608	>	(reducer = this.reducer) != null) {
5609	>	long r = this.basis;
5610	>	for (int i = baseIndex, f, h; batch > 0 &&
5611	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5612	>	addToPendingCount(1);
5613	>	(rights = new MapReduceMappingsToLongTask<K,V>
5614	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5615	>	rights, transformer, r, reducer)).fork();
5616	>	}
5617	>	for (Node<K,V> p; (p = advance()) != null; )
5618	>	r = reducer.applyAsLong(r, transformer.applyAsLong((K)p.key, p.val));
5619	>	result = r;
5620	>	CountedCompleter<?> c;
5621	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5622	>	MapReduceMappingsToLongTask<K,V>
5623	>	t = (MapReduceMappingsToLongTask<K,V>)c,
5624	>	s = t.rights;
5625	>	while (s != null) {
5626	>	t.result = reducer.applyAsLong(t.result, s.result);
5627	>	s = t.rights = s.nextRight;
5628	>	}
5629	>	}
5630	>	}
5631	>	}
5632	>	}
5633	>
5634	>	static final class MapReduceKeysToIntTask<K,V>
5635	>	extends BulkTask<K,V,Integer> {
5636	>	final ToIntFunction<? super K> transformer;
5637	>	final IntBinaryOperator reducer;
5638	>	final int basis;
5639	>	int result;
5640	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
5641	>	MapReduceKeysToIntTask
5642	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5643	>	MapReduceKeysToIntTask<K,V> nextRight,
5644	>	ToIntFunction<? super K> transformer,
5645	>	int basis,
5646	>	IntBinaryOperator reducer) {
5647	>	super(p, b, i, f, t); this.nextRight = nextRight;
5648	>	this.transformer = transformer;
5649	>	this.basis = basis; this.reducer = reducer;
5650	>	}
5651	>	public final Integer getRawResult() { return result; }
5652	>	public final void compute() {
5653	>	final ToIntFunction<? super K> transformer;
5654	>	final IntBinaryOperator reducer;
5655	>	if ((transformer = this.transformer) != null &&
5656	>	(reducer = this.reducer) != null) {
5657	>	int r = this.basis;
5658	>	for (int i = baseIndex, f, h; batch > 0 &&
5659	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5660	>	addToPendingCount(1);
5661	>	(rights = new MapReduceKeysToIntTask<K,V>
5662	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5663	>	rights, transformer, r, reducer)).fork();
5664	>	}
5665	>	for (Node<K,V> p; (p = advance()) != null; )
5666	>	r = reducer.applyAsInt(r, transformer.applyAsInt((K)p.key));
5667	>	result = r;
5668	>	CountedCompleter<?> c;
5669	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5670	>	MapReduceKeysToIntTask<K,V>
5671	>	t = (MapReduceKeysToIntTask<K,V>)c,
5672	>	s = t.rights;
5673	>	while (s != null) {
5674	>	t.result = reducer.applyAsInt(t.result, s.result);
5675	>	s = t.rights = s.nextRight;
5676	>	}
5677	>	}
5678	>	}
5679	>	}
5680	>	}
5681	>
5682	>	static final class MapReduceValuesToIntTask<K,V>
5683	>	extends BulkTask<K,V,Integer> {
5684	>	final ToIntFunction<? super V> transformer;
5685	>	final IntBinaryOperator reducer;
5686	>	final int basis;
5687	>	int result;
5688	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
5689	>	MapReduceValuesToIntTask
5690	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5691	>	MapReduceValuesToIntTask<K,V> nextRight,
5692	>	ToIntFunction<? super V> transformer,
5693	>	int basis,
5694	>	IntBinaryOperator reducer) {
5695	>	super(p, b, i, f, t); this.nextRight = nextRight;
5696	>	this.transformer = transformer;
5697	>	this.basis = basis; this.reducer = reducer;
5698	>	}
5699	>	public final Integer getRawResult() { return result; }
5700	>	public final void compute() {
5701	>	final ToIntFunction<? super V> transformer;
5702	>	final IntBinaryOperator reducer;
5703	>	if ((transformer = this.transformer) != null &&
5704	>	(reducer = this.reducer) != null) {
5705	>	int r = this.basis;
5706	>	for (int i = baseIndex, f, h; batch > 0 &&
5707	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5708	>	addToPendingCount(1);
5709	>	(rights = new MapReduceValuesToIntTask<K,V>
5710	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5711	>	rights, transformer, r, reducer)).fork();
5712	>	}
5713	>	for (Node<K,V> p; (p = advance()) != null; )
5714	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
5715	>	result = r;
5716	>	CountedCompleter<?> c;
5717	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5718	>	MapReduceValuesToIntTask<K,V>
5719	>	t = (MapReduceValuesToIntTask<K,V>)c,
5720	>	s = t.rights;
5721	>	while (s != null) {
5722	>	t.result = reducer.applyAsInt(t.result, s.result);
5723	>	s = t.rights = s.nextRight;
5724	>	}
5725	>	}
5726	>	}
5727	>	}
5728	>	}
5729	>
5730	>	static final class MapReduceEntriesToIntTask<K,V>
5731	>	extends BulkTask<K,V,Integer> {
5732	>	final ToIntFunction<Map.Entry<K,V>> transformer;
5733	>	final IntBinaryOperator reducer;
5734	>	final int basis;
5735	>	int result;
5736	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
5737	>	MapReduceEntriesToIntTask
5738	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5739	>	MapReduceEntriesToIntTask<K,V> nextRight,
5740	>	ToIntFunction<Map.Entry<K,V>> transformer,
5741	>	int basis,
5742	>	IntBinaryOperator reducer) {
5743	>	super(p, b, i, f, t); this.nextRight = nextRight;
5744	>	this.transformer = transformer;
5745	>	this.basis = basis; this.reducer = reducer;
5746	>	}
5747	>	public final Integer getRawResult() { return result; }
5748	>	public final void compute() {
5749	>	final ToIntFunction<Map.Entry<K,V>> transformer;
5750	>	final IntBinaryOperator reducer;
5751	>	if ((transformer = this.transformer) != null &&
5752	>	(reducer = this.reducer) != null) {
5753	>	int r = this.basis;
5754	>	for (int i = baseIndex, f, h; batch > 0 &&
5755	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5756	>	addToPendingCount(1);
5757	>	(rights = new MapReduceEntriesToIntTask<K,V>
5758	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5759	>	rights, transformer, r, reducer)).fork();
5760	>	}
5761	>	for (Node<K,V> p; (p = advance()) != null; )
5762	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
5763	>	result = r;
5764	>	CountedCompleter<?> c;
5765	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5766	>	MapReduceEntriesToIntTask<K,V>
5767	>	t = (MapReduceEntriesToIntTask<K,V>)c,
5768	>	s = t.rights;
5769	>	while (s != null) {
5770	>	t.result = reducer.applyAsInt(t.result, s.result);
5771	>	s = t.rights = s.nextRight;
5772	>	}
5773	>	}
5774	>	}
5775	>	}
5776	>	}
5777	>
5778	>	static final class MapReduceMappingsToIntTask<K,V>
5779	>	extends BulkTask<K,V,Integer> {
5780	>	final ToIntBiFunction<? super K, ? super V> transformer;
5781	>	final IntBinaryOperator reducer;
5782	>	final int basis;
5783	>	int result;
5784	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
5785	>	MapReduceMappingsToIntTask
5786	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5787	>	MapReduceMappingsToIntTask<K,V> nextRight,
5788	>	ToIntBiFunction<? super K, ? super V> transformer,
5789	>	int basis,
5790	>	IntBinaryOperator reducer) {
5791	>	super(p, b, i, f, t); this.nextRight = nextRight;
5792	>	this.transformer = transformer;
5793	>	this.basis = basis; this.reducer = reducer;
5794	>	}
5795	>	public final Integer getRawResult() { return result; }
5796	>	public final void compute() {
5797	>	final ToIntBiFunction<? super K, ? super V> transformer;
5798	>	final IntBinaryOperator reducer;
5799	>	if ((transformer = this.transformer) != null &&
5800	>	(reducer = this.reducer) != null) {
5801	>	int r = this.basis;
5802	>	for (int i = baseIndex, f, h; batch > 0 &&
5803	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5804	>	addToPendingCount(1);
5805	>	(rights = new MapReduceMappingsToIntTask<K,V>
5806	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5807	>	rights, transformer, r, reducer)).fork();
5808	>	}
5809	>	for (Node<K,V> p; (p = advance()) != null; )
5810	>	r = reducer.applyAsInt(r, transformer.applyAsInt((K)p.key, p.val));
5811	>	result = r;
5812	>	CountedCompleter<?> c;
5813	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5814	>	MapReduceMappingsToIntTask<K,V>
5815	>	t = (MapReduceMappingsToIntTask<K,V>)c,
5816	>	s = t.rights;
5817	>	while (s != null) {
5818	>	t.result = reducer.applyAsInt(t.result, s.result);
5819	>	s = t.rights = s.nextRight;
5820	>	}
5821	>	}
5822	>	}
5823		}
5824		}
5825
5826		// Unsafe mechanics
5827	<	private static final sun.misc.Unsafe UNSAFE;
5828	<	private static final long SBASE;
5829	<	private static final int SSHIFT;
5830	<	private static final long TBASE;
5831	<	private static final int TSHIFT;
5827	>	private static final sun.misc.Unsafe U;
5828	>	private static final long SIZECTL;
5829	>	private static final long TRANSFERINDEX;
5830	>	private static final long TRANSFERORIGIN;
5831	>	private static final long BASECOUNT;
5832	>	private static final long CELLSBUSY;
5833	>	private static final long CELLVALUE;
5834	>	private static final long ABASE;
5835	>	private static final int ASHIFT;
5836
5837		static {
1474	–	int ss, ts;
5838		try {
5839	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
5840	<	Class tc = HashEntry[].class;
5841	<	Class sc = Segment[].class;
5842	<	TBASE = UNSAFE.arrayBaseOffset(tc);
5843	<	SBASE = UNSAFE.arrayBaseOffset(sc);
5844	<	ts = UNSAFE.arrayIndexScale(tc);
5845	<	ss = UNSAFE.arrayIndexScale(sc);
5839	>	U = sun.misc.Unsafe.getUnsafe();
5840	>	Class<?> k = ConcurrentHashMap.class;
5841	>	SIZECTL = U.objectFieldOffset
5842	>	(k.getDeclaredField("sizeCtl"));
5843	>	TRANSFERINDEX = U.objectFieldOffset
5844	>	(k.getDeclaredField("transferIndex"));
5845	>	TRANSFERORIGIN = U.objectFieldOffset
5846	>	(k.getDeclaredField("transferOrigin"));
5847	>	BASECOUNT = U.objectFieldOffset
5848	>	(k.getDeclaredField("baseCount"));
5849	>	CELLSBUSY = U.objectFieldOffset
5850	>	(k.getDeclaredField("cellsBusy"));
5851	>	Class<?> ck = Cell.class;
5852	>	CELLVALUE = U.objectFieldOffset
5853	>	(ck.getDeclaredField("value"));
5854	>	Class<?> sc = Node[].class;
5855	>	ABASE = U.arrayBaseOffset(sc);
5856	>	int scale = U.arrayIndexScale(sc);
5857	>	if ((scale & (scale - 1)) != 0)
5858	>	throw new Error("data type scale not a power of two");
5859	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
5860		} catch (Exception e) {
5861		throw new Error(e);
5862		}
1486	–	if ((ss & (ss-1)) != 0 || (ts & (ts-1)) != 0)
1487	–	throw new Error("data type scale not a power of two");
1488	–	SSHIFT = 31 - Integer.numberOfLeadingZeros(ss);
1489	–	TSHIFT = 31 - Integer.numberOfLeadingZeros(ts);
5863		}
1491	–
5864		}

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