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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.112 by jsr166, Fri Jun 3 02:28:05 2011 UTC vs.
Revision 1.268 by jsr166, Wed Mar 4 00:22:30 2015 UTC

#	Line 5 | Line 5
5		*/
6
7		package java.util.concurrent;
8	<	import java.util.concurrent.locks.*;
9	<	import java.util.*;
8	>
9	>	import java.io.ObjectStreamField;
10		import java.io.Serializable;
11	<	import java.io.IOException;
12	<	import java.io.ObjectInputStream;
13	<	import java.io.ObjectOutputStream;
11	>	import java.lang.reflect.ParameterizedType;
12	>	import java.lang.reflect.Type;
13	>	import java.util.AbstractMap;
14	>	import java.util.Arrays;
15	>	import java.util.Collection;
16	>	import java.util.Enumeration;
17	>	import java.util.HashMap;
18	>	import java.util.Hashtable;
19	>	import java.util.Iterator;
20	>	import java.util.Map;
21	>	import java.util.NoSuchElementException;
22	>	import java.util.Set;
23	>	import java.util.Spliterator;
24	>	import java.util.concurrent.atomic.AtomicReference;
25	>	import java.util.concurrent.locks.LockSupport;
26	>	import java.util.concurrent.locks.ReentrantLock;
27	>	import java.util.function.BiConsumer;
28	>	import java.util.function.BiFunction;
29	>	import java.util.function.Consumer;
30	>	import java.util.function.DoubleBinaryOperator;
31	>	import java.util.function.Function;
32	>	import java.util.function.IntBinaryOperator;
33	>	import java.util.function.LongBinaryOperator;
34	>	import java.util.function.ToDoubleBiFunction;
35	>	import java.util.function.ToDoubleFunction;
36	>	import java.util.function.ToIntBiFunction;
37	>	import java.util.function.ToIntFunction;
38	>	import java.util.function.ToLongBiFunction;
39	>	import java.util.function.ToLongFunction;
40	>	import java.util.stream.Stream;
41
42		/**
43		* A hash table supporting full concurrency of retrievals and
44	<	* adjustable expected concurrency for updates. This class obeys the
44	>	* high expected concurrency for updates. This class obeys the
45		* same functional specification as {@link java.util.Hashtable}, and
46		* includes versions of methods corresponding to each method of
47	<	* <tt>Hashtable</tt>. However, even though all operations are
47	>	* {@code Hashtable}. However, even though all operations are
48		* thread-safe, retrieval operations do <em>not</em> entail locking,
49		* and there is <em>not</em> any support for locking the entire table
50		* in a way that prevents all access.  This class is fully
51	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
51	>	* interoperable with {@code Hashtable} in programs that rely on its
52		* thread safety but not on its synchronization details.
53		*
54	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
55	<	* block, so may overlap with update operations (including
56	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
57	<	* of the most recently <em>completed</em> update operations holding
58	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
59	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
60	<	* removal of only some entries.  Similarly, Iterators and
61	<	* Enumerations return elements reflecting the state of the hash table
62	<	* at some point at or since the creation of the iterator/enumeration.
63	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
54	>	* <p>Retrieval operations (including {@code get}) generally do not
55	>	* block, so may overlap with update operations (including {@code put}
56	>	* and {@code remove}). Retrievals reflect the results of the most
57	>	* recently <em>completed</em> update operations holding upon their
58	>	* onset. (More formally, an update operation for a given key bears a
59	>	* <em>happens-before</em> relation with any (non-null) retrieval for
60	>	* that key reporting the updated value.)  For aggregate operations
61	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
62	>	* reflect insertion or removal of only some entries.  Similarly,
63	>	* Iterators, Spliterators and Enumerations return elements reflecting the
64	>	* state of the hash table at some point at or since the creation of the
65	>	* iterator/enumeration.  They do <em>not</em> throw {@link
66	>	* java.util.ConcurrentModificationException ConcurrentModificationException}.
67		* However, iterators are designed to be used by only one thread at a time.
68	+	* Bear in mind that the results of aggregate status methods including
69	+	* {@code size}, {@code isEmpty}, and {@code containsValue} are typically
70	+	* useful only when a map is not undergoing concurrent updates in other threads.
71	+	* Otherwise the results of these methods reflect transient states
72	+	* that may be adequate for monitoring or estimation purposes, but not
73	+	* for program control.
74	+	*
75	+	* <p>The table is dynamically expanded when there are too many
76	+	* collisions (i.e., keys that have distinct hash codes but fall into
77	+	* the same slot modulo the table size), with the expected average
78	+	* effect of maintaining roughly two bins per mapping (corresponding
79	+	* to a 0.75 load factor threshold for resizing). There may be much
80	+	* variance around this average as mappings are added and removed, but
81	+	* overall, this maintains a commonly accepted time/space tradeoff for
82	+	* hash tables.  However, resizing this or any other kind of hash
83	+	* table may be a relatively slow operation. When possible, it is a
84	+	* good idea to provide a size estimate as an optional {@code
85	+	* initialCapacity} constructor argument. An additional optional
86	+	* {@code loadFactor} constructor argument provides a further means of
87	+	* customizing initial table capacity by specifying the table density
88	+	* to be used in calculating the amount of space to allocate for the
89	+	* given number of elements.  Also, for compatibility with previous
90	+	* versions of this class, constructors may optionally specify an
91	+	* expected {@code concurrencyLevel} as an additional hint for
92	+	* internal sizing.  Note that using many keys with exactly the same
93	+	* {@code hashCode()} is a sure way to slow down performance of any
94	+	* hash table. To ameliorate impact, when keys are {@link Comparable},
95	+	* this class may use comparison order among keys to help break ties.
96	+	*
97	+	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
98	+	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
99	+	* (using {@link #keySet(Object)} when only keys are of interest, and the
100	+	* mapped values are (perhaps transiently) not used or all take the
101	+	* same mapping value.
102		*
103	<	* <p> The allowed concurrency among update operations is guided by
104	<	* the optional <tt>concurrencyLevel</tt> constructor argument
105	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
106	<	* table is internally partitioned to try to permit the indicated
107	<	* number of concurrent updates without contention. Because placement
108	<	* in hash tables is essentially random, the actual concurrency will
45	<	* vary.  Ideally, you should choose a value to accommodate as many
46	<	* threads as will ever concurrently modify the table. Using a
47	<	* significantly higher value than you need can waste space and time,
48	<	* and a significantly lower value can lead to thread contention. But
49	<	* overestimates and underestimates within an order of magnitude do
50	<	* not usually have much noticeable impact. A value of one is
51	<	* appropriate when it is known that only one thread will modify and
52	<	* all others will only read. Also, resizing this or any other kind of
53	<	* hash table is a relatively slow operation, so, when possible, it is
54	<	* a good idea to provide estimates of expected table sizes in
55	<	* constructors.
103	>	* <p>A ConcurrentHashMap can be used as a scalable frequency map (a
104	>	* form of histogram or multiset) by using {@link
105	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
106	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
107	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
108	>	* {@code freqs.computeIfAbsent(key, k -> new LongAdder()).increment();}
109		*
110		* <p>This class and its views and iterators implement all of the
111		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
112		* interfaces.
113		*
114	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
115	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
114	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
115	>	* does <em>not</em> allow {@code null} to be used as a key or value.
116	>	*
117	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
118	>	* operations that, unlike most {@link Stream} methods, are designed
119	>	* to be safely, and often sensibly, applied even with maps that are
120	>	* being concurrently updated by other threads; for example, when
121	>	* computing a snapshot summary of the values in a shared registry.
122	>	* There are three kinds of operation, each with four forms, accepting
123	>	* functions with Keys, Values, Entries, and (Key, Value) arguments
124	>	* and/or return values. Because the elements of a ConcurrentHashMap
125	>	* are not ordered in any particular way, and may be processed in
126	>	* different orders in different parallel executions, the correctness
127	>	* of supplied functions should not depend on any ordering, or on any
128	>	* other objects or values that may transiently change while
129	>	* computation is in progress; and except for forEach actions, should
130	>	* ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry}
131	>	* objects do not support method {@code setValue}.
132	>	*
133	>	* <ul>
134	>	* <li> forEach: Perform a given action on each element.
135	>	* A variant form applies a given transformation on each element
136	>	* before performing the action.</li>
137	>	*
138	>	* <li> search: Return the first available non-null result of
139	>	* applying a given function on each element; skipping further
140	>	* search when a result is found.</li>
141	>	*
142	>	* <li> reduce: Accumulate each element.  The supplied reduction
143	>	* function cannot rely on ordering (more formally, it should be
144	>	* both associative and commutative).  There are five variants:
145	>	*
146	>	* <ul>
147	>	*
148	>	* <li> Plain reductions. (There is not a form of this method for
149	>	* (key, value) function arguments since there is no corresponding
150	>	* return type.)</li>
151	>	*
152	>	* <li> Mapped reductions that accumulate the results of a given
153	>	* function applied to each element.</li>
154	>	*
155	>	* <li> Reductions to scalar doubles, longs, and ints, using a
156	>	* given basis value.</li>
157	>	*
158	>	* </ul>
159	>	* </li>
160	>	* </ul>
161	>	*
162	>	* <p>These bulk operations accept a {@code parallelismThreshold}
163	>	* argument. Methods proceed sequentially if the current map size is
164	>	* estimated to be less than the given threshold. Using a value of
165	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
166	>	* of {@code 1} results in maximal parallelism by partitioning into
167	>	* enough subtasks to fully utilize the {@link
168	>	* ForkJoinPool#commonPool()} that is used for all parallel
169	>	* computations. Normally, you would initially choose one of these
170	>	* extreme values, and then measure performance of using in-between
171	>	* values that trade off overhead versus throughput.
172	>	*
173	>	* <p>The concurrency properties of bulk operations follow
174	>	* from those of ConcurrentHashMap: Any non-null result returned
175	>	* from {@code get(key)} and related access methods bears a
176	>	* happens-before relation with the associated insertion or
177	>	* update.  The result of any bulk operation reflects the
178	>	* composition of these per-element relations (but is not
179	>	* necessarily atomic with respect to the map as a whole unless it
180	>	* is somehow known to be quiescent).  Conversely, because keys
181	>	* and values in the map are never null, null serves as a reliable
182	>	* atomic indicator of the current lack of any result.  To
183	>	* maintain this property, null serves as an implicit basis for
184	>	* all non-scalar reduction operations. For the double, long, and
185	>	* int versions, the basis should be one that, when combined with
186	>	* any other value, returns that other value (more formally, it
187	>	* should be the identity element for the reduction). Most common
188	>	* reductions have these properties; for example, computing a sum
189	>	* with basis 0 or a minimum with basis MAX_VALUE.
190	>	*
191	>	* <p>Search and transformation functions provided as arguments
192	>	* should similarly return null to indicate the lack of any result
193	>	* (in which case it is not used). In the case of mapped
194	>	* reductions, this also enables transformations to serve as
195	>	* filters, returning null (or, in the case of primitive
196	>	* specializations, the identity basis) if the element should not
197	>	* be combined. You can create compound transformations and
198	>	* filterings by composing them yourself under this "null means
199	>	* there is nothing there now" rule before using them in search or
200	>	* reduce operations.
201	>	*
202	>	* <p>Methods accepting and/or returning Entry arguments maintain
203	>	* key-value associations. They may be useful for example when
204	>	* finding the key for the greatest value. Note that "plain" Entry
205	>	* arguments can be supplied using {@code new
206	>	* AbstractMap.SimpleEntry(k,v)}.
207	>	*
208	>	* <p>Bulk operations may complete abruptly, throwing an
209	>	* exception encountered in the application of a supplied
210	>	* function. Bear in mind when handling such exceptions that other
211	>	* concurrently executing functions could also have thrown
212	>	* exceptions, or would have done so if the first exception had
213	>	* not occurred.
214	>	*
215	>	* <p>Speedups for parallel compared to sequential forms are common
216	>	* but not guaranteed.  Parallel operations involving brief functions
217	>	* on small maps may execute more slowly than sequential forms if the
218	>	* underlying work to parallelize the computation is more expensive
219	>	* than the computation itself.  Similarly, parallelization may not
220	>	* lead to much actual parallelism if all processors are busy
221	>	* performing unrelated tasks.
222	>	*
223	>	* <p>All arguments to all task methods must be non-null.
224		*
225		* <p>This class is a member of the
226		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
#	Line 70 | Line 231 | import java.io.ObjectOutputStream;
231		* @param <K> the type of keys maintained by this map
232		* @param <V> the type of mapped values
233		*/
234	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
235	<	implements ConcurrentMap<K, V>, Serializable {
234	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
235	>	implements ConcurrentMap<K,V>, Serializable {
236		private static final long serialVersionUID = 7249069246763182397L;
237
238		/*
239	<	* The basic strategy is to subdivide the table among Segments,
240	<	* each of which itself is a concurrently readable hash table.  To
241	<	* reduce footprint, all but one segments are constructed only
242	<	* when first needed (see ensureSegment). To maintain visibility
243	<	* in the presence of lazy construction, accesses to segments as
244	<	* well as elements of segment's table must use volatile access,
245	<	* which is done via Unsafe within methods segmentAt etc
246	<	* below. These provide the functionality of AtomicReferenceArrays
247	<	* but reduce the levels of indirection. Additionally,
248	<	* volatile-writes of table elements and entry "next" fields
249	<	* within locked operations use the cheaper "lazySet" forms of
250	<	* writes (via putOrderedObject) because these writes are always
251	<	* followed by lock releases that maintain sequential consistency
252	<	* of table updates.
253	<	*
254	<	* Historical note: The previous version of this class relied
255	<	* heavily on "final" fields, which avoided some volatile reads at
256	<	* the expense of a large initial footprint.  Some remnants of
257	<	* that design (including forced construction of segment 0) exist
258	<	* to ensure serialization compatibility.
239	>	* Overview:
240	>	*
241	>	* The primary design goal of this hash table is to maintain
242	>	* concurrent readability (typically method get(), but also
243	>	* iterators and related methods) while minimizing update
244	>	* contention. Secondary goals are to keep space consumption about
245	>	* the same or better than java.util.HashMap, and to support high
246	>	* initial insertion rates on an empty table by many threads.
247	>	*
248	>	* This map usually acts as a binned (bucketed) hash table.  Each
249	>	* key-value mapping is held in a Node.  Most nodes are instances
250	>	* of the basic Node class with hash, key, value, and next
251	>	* fields. However, various subclasses exist: TreeNodes are
252	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
253	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
254	>	* of bins during resizing. ReservationNodes are used as
255	>	* placeholders while establishing values in computeIfAbsent and
256	>	* related methods.  The types TreeBin, ForwardingNode, and
257	>	* ReservationNode do not hold normal user keys, values, or
258	>	* hashes, and are readily distinguishable during search etc
259	>	* because they have negative hash fields and null key and value
260	>	* fields. (These special nodes are either uncommon or transient,
261	>	* so the impact of carrying around some unused fields is
262	>	* insignificant.)
263	>	*
264	>	* The table is lazily initialized to a power-of-two size upon the
265	>	* first insertion.  Each bin in the table normally contains a
266	>	* list of Nodes (most often, the list has only zero or one Node).
267	>	* Table accesses require volatile/atomic reads, writes, and
268	>	* CASes.  Because there is no other way to arrange this without
269	>	* adding further indirections, we use intrinsics
270	>	* (sun.misc.Unsafe) operations.
271	>	*
272	>	* We use the top (sign) bit of Node hash fields for control
273	>	* purposes -- it is available anyway because of addressing
274	>	* constraints.  Nodes with negative hash fields are specially
275	>	* handled or ignored in map methods.
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 or ones that differs only
326	>	* in masked-out high bits. So we use a secondary strategy that
327	>	* applies when the number of nodes in a bin exceeds a
328	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
329	>	* specialized form of red-black trees), bounding search time to
330	>	* O(log N).  Each search step in a TreeBin is at least twice as
331	>	* slow as in a regular list, but given that N cannot exceed
332	>	* (1<<64) (before running out of addresses) this bounds search
333	>	* steps, lock hold times, etc, to reasonable constants (roughly
334	>	* 100 nodes inspected per operation worst case) so long as keys
335	>	* are Comparable (which is very common -- String, Long, etc).
336	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
337	>	* traversal pointers as regular nodes, so can be traversed in
338	>	* iterators in the same way.
339	>	*
340	>	* The table is resized when occupancy exceeds a percentage
341	>	* threshold (nominally, 0.75, but see below).  Any thread
342	>	* noticing an overfull bin may assist in resizing after the
343	>	* initiating thread allocates and sets up the replacement array.
344	>	* However, rather than stalling, these other threads may proceed
345	>	* with insertions etc.  The use of TreeBins shields us from the
346	>	* worst case effects of overfilling while resizes are in
347	>	* progress.  Resizing proceeds by transferring bins, one by one,
348	>	* from the table to the next table. However, threads claim small
349	>	* blocks of indices to transfer (via field transferIndex) before
350	>	* doing so, reducing contention.  A generation stamp in field
351	>	* sizeCtl ensures that resizings do not overlap. Because we are
352	>	* using power-of-two expansion, the elements from each bin must
353	>	* either stay at same index, or move with a power of two
354	>	* offset. We eliminate unnecessary node creation by catching
355	>	* cases where old nodes can be reused because their next fields
356	>	* won't change.  On average, only about one-sixth of them need
357	>	* cloning when a table doubles. The nodes they replace will be
358	>	* garbage collectable as soon as they are no longer referenced by
359	>	* any reader thread that may be in the midst of concurrently
360	>	* traversing table.  Upon transfer, the old table bin contains
361	>	* only a special forwarding node (with hash field "MOVED") that
362	>	* contains the next table as its key. On encountering a
363	>	* forwarding node, access and update operations restart, using
364	>	* the new table.
365	>	*
366	>	* Each bin transfer requires its bin lock, which can stall
367	>	* waiting for locks while resizing. However, because other
368	>	* threads can join in and help resize rather than contend for
369	>	* locks, average aggregate waits become shorter as resizing
370	>	* progresses.  The transfer operation must also ensure that all
371	>	* accessible bins in both the old and new table are usable by any
372	>	* traversal.  This is arranged in part by proceeding from the
373	>	* last bin (table.length - 1) up towards the first.  Upon seeing
374	>	* a forwarding node, traversals (see class Traverser) arrange to
375	>	* move to the new table without revisiting nodes.  To ensure that
376	>	* no intervening nodes are skipped even when moved out of order,
377	>	* a stack (see class TableStack) is created on first encounter of
378	>	* a forwarding node during a traversal, to maintain its place if
379	>	* later processing the current table. The need for these
380	>	* save/restore mechanics is relatively rare, but when one
381	>	* forwarding node is encountered, typically many more will be.
382	>	* So Traversers use a simple caching scheme to avoid creating so
383	>	* many new TableStack nodes. (Thanks to Peter Levart for
384	>	* suggesting use of a stack here.)
385	>	*
386	>	* The traversal scheme also applies to partial traversals of
387	>	* ranges of bins (via an alternate Traverser constructor)
388	>	* to support partitioned aggregate operations.  Also, read-only
389	>	* operations give up if ever forwarded to a null table, which
390	>	* provides support for shutdown-style clearing, which is also not
391	>	* currently implemented.
392	>	*
393	>	* Lazy table initialization minimizes footprint until first use,
394	>	* and also avoids resizings when the first operation is from a
395	>	* putAll, constructor with map argument, or deserialization.
396	>	* These cases attempt to override the initial capacity settings,
397	>	* but harmlessly fail to take effect in cases of races.
398	>	*
399	>	* The element count is maintained using a specialization of
400	>	* LongAdder. We need to incorporate a specialization rather than
401	>	* just use a LongAdder in order to access implicit
402	>	* contention-sensing that leads to creation of multiple
403	>	* CounterCells.  The counter mechanics avoid contention on
404	>	* updates but can encounter cache thrashing if read too
405	>	* frequently during concurrent access. To avoid reading so often,
406	>	* resizing under contention is attempted only upon adding to a
407	>	* bin already holding two or more nodes. Under uniform hash
408	>	* distributions, the probability of this occurring at threshold
409	>	* is around 13%, meaning that only about 1 in 8 puts check
410	>	* threshold (and after resizing, many fewer do so).
411	>	*
412	>	* TreeBins use a special form of comparison for search and
413	>	* related operations (which is the main reason we cannot use
414	>	* existing collections such as TreeMaps). TreeBins contain
415	>	* Comparable elements, but may contain others, as well as
416	>	* elements that are Comparable but not necessarily Comparable for
417	>	* the same T, so we cannot invoke compareTo among them. To handle
418	>	* this, the tree is ordered primarily by hash value, then by
419	>	* Comparable.compareTo order if applicable.  On lookup at a node,
420	>	* if elements are not comparable or compare as 0 then both left
421	>	* and right children may need to be searched in the case of tied
422	>	* hash values. (This corresponds to the full list search that
423	>	* would be necessary if all elements were non-Comparable and had
424	>	* tied hashes.) On insertion, to keep a total ordering (or as
425	>	* close as is required here) across rebalancings, we compare
426	>	* classes and identityHashCodes as tie-breakers. The red-black
427	>	* balancing code is updated from pre-jdk-collections
428	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
429	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
430	>	* Algorithms" (CLR).
431	>	*
432	>	* TreeBins also require an additional locking mechanism.  While
433	>	* list traversal is always possible by readers even during
434	>	* updates, tree traversal is not, mainly because of tree-rotations
435	>	* that may change the root node and/or its linkages.  TreeBins
436	>	* include a simple read-write lock mechanism parasitic on the
437	>	* main bin-synchronization strategy: Structural adjustments
438	>	* associated with an insertion or removal are already bin-locked
439	>	* (and so cannot conflict with other writers) but must wait for
440	>	* ongoing readers to finish. Since there can be only one such
441	>	* waiter, we use a simple scheme using a single "waiter" field to
442	>	* block writers.  However, readers need never block.  If the root
443	>	* lock is held, they proceed along the slow traversal path (via
444	>	* next-pointers) until the lock becomes available or the list is
445	>	* exhausted, whichever comes first. These cases are not fast, but
446	>	* maximize aggregate expected throughput.
447	>	*
448	>	* Maintaining API and serialization compatibility with previous
449	>	* versions of this class introduces several oddities. Mainly: We
450	>	* leave untouched but unused constructor arguments refering to
451	>	* concurrencyLevel. We accept a loadFactor constructor argument,
452	>	* but apply it only to initial table capacity (which is the only
453	>	* time that we can guarantee to honor it.) We also declare an
454	>	* unused "Segment" class that is instantiated in minimal form
455	>	* only when serializing.
456	>	*
457	>	* Also, solely for compatibility with previous versions of this
458	>	* class, it extends AbstractMap, even though all of its methods
459	>	* are overridden, so it is just useless baggage.
460	>	*
461	>	* This file is organized to make things a little easier to follow
462	>	* while reading than they might otherwise: First the main static
463	>	* declarations and utilities, then fields, then main public
464	>	* methods (with a few factorings of multiple public methods into
465	>	* internal ones), then sizing methods, trees, traversers, and
466	>	* bulk operations.
467		*/
468
469		/* ---------------- Constants -------------- */
470
471		/**
472	<	* The default initial capacity for this table,
473	<	* used when not otherwise specified in a constructor.
472	>	* The largest possible table capacity.  This value must be
473	>	* exactly 1<<30 to stay within Java array allocation and indexing
474	>	* bounds for power of two table sizes, and is further required
475	>	* because the top two bits of 32bit hash fields are used for
476	>	* control purposes.
477		*/
478	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
478	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
479
480		/**
481	<	* The default load factor for this table, used when not
482	<	* otherwise specified in a constructor.
481	>	* The default initial table capacity.  Must be a power of 2
482	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
483		*/
484	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
484	>	private static final int DEFAULT_CAPACITY = 16;
485
486		/**
487	<	* The default concurrency level for this table, used when not
488	<	* otherwise specified in a constructor.
487	>	* The largest possible (non-power of two) array size.
488	>	* Needed by toArray and related methods.
489		*/
490	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
490	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
491
492		/**
493	<	* The maximum capacity, used if a higher value is implicitly
494	<	* 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.
493	>	* The default concurrency level for this table. Unused but
494	>	* defined for compatibility with previous versions of this class.
495		*/
496	<	static final int MAXIMUM_CAPACITY = 1 << 30;
496	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
497
498		/**
499	<	* The minimum capacity for per-segment tables.  Must be a power
500	<	* of two, at least two to avoid immediate resizing on next use
501	<	* after lazy construction.
499	>	* The load factor for this table. Overrides of this value in
500	>	* constructors affect only the initial table capacity.  The
501	>	* actual floating point value isn't normally used -- it is
502	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
503	>	* the associated resizing threshold.
504		*/
505	<	static final int MIN_SEGMENT_TABLE_CAPACITY = 2;
505	>	private static final float LOAD_FACTOR = 0.75f;
506
507		/**
508	<	* The maximum number of segments to allow; used to bound
509	<	* constructor arguments. Must be power of two less than 1 << 24.
508	>	* The bin count threshold for using a tree rather than list for a
509	>	* bin.  Bins are converted to trees when adding an element to a
510	>	* bin with at least this many nodes. The value must be greater
511	>	* than 2, and should be at least 8 to mesh with assumptions in
512	>	* tree removal about conversion back to plain bins upon
513	>	* shrinkage.
514		*/
515	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
515	>	static final int TREEIFY_THRESHOLD = 8;
516
517		/**
518	<	* Number of unsynchronized retries in size and containsValue
519	<	* methods before resorting to locking. This is used to avoid
520	<	* unbounded retries if tables undergo continuous modification
145	<	* which would make it impossible to obtain an accurate result.
518	>	* The bin count threshold for untreeifying a (split) bin during a
519	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
520	>	* most 6 to mesh with shrinkage detection under removal.
521		*/
522	<	static final int RETRIES_BEFORE_LOCK = 2;
148	<
149	<	/* ---------------- Fields -------------- */
522	>	static final int UNTREEIFY_THRESHOLD = 6;
523
524		/**
525	<	* Mask value for indexing into segments. The upper bits of a
526	<	* key's hash code are used to choose the segment.
525	>	* The smallest table capacity for which bins may be treeified.
526	>	* (Otherwise the table is resized if too many nodes in a bin.)
527	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
528	>	* conflicts between resizing and treeification thresholds.
529		*/
530	<	final int segmentMask;
530	>	static final int MIN_TREEIFY_CAPACITY = 64;
531
532		/**
533	<	* Shift value for indexing within segments.
533	>	* Minimum number of rebinnings per transfer step. Ranges are
534	>	* subdivided to allow multiple resizer threads.  This value
535	>	* serves as a lower bound to avoid resizers encountering
536	>	* excessive memory contention.  The value should be at least
537	>	* DEFAULT_CAPACITY.
538		*/
539	<	final int segmentShift;
539	>	private static final int MIN_TRANSFER_STRIDE = 16;
540
541		/**
542	<	* The segments, each of which is a specialized hash table.
542	>	* The number of bits used for generation stamp in sizeCtl.
543	>	* Must be at least 6 for 32bit arrays.
544		*/
545	<	final Segment<K,V>[] segments;
545	>	private static int RESIZE_STAMP_BITS = 16;
546
547	<	transient Set<K> keySet;
548	<	transient Set<Map.Entry<K,V>> entrySet;
549	<	transient Collection<V> values;
547	>	/**
548	>	* The maximum number of threads that can help resize.
549	>	* Must fit in 32 - RESIZE_STAMP_BITS bits.
550	>	*/
551	>	private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
552
553		/**
554	<	* ConcurrentHashMap list entry. Note that this is never exported
555	<	* out as a user-visible Map.Entry.
554	>	* The bit shift for recording size stamp in sizeCtl.
555	>	*/
556	>	private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
557	>
558	>	/*
559	>	* Encodings for Node hash fields. See above for explanation.
560	>	*/
561	>	static final int MOVED     = -1; // hash for forwarding nodes
562	>	static final int TREEBIN   = -2; // hash for roots of trees
563	>	static final int RESERVED  = -3; // hash for transient reservations
564	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
565	>
566	>	/** Number of CPUS, to place bounds on some sizings */
567	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
568	>
569	>	/** For serialization compatibility. */
570	>	private static final ObjectStreamField[] serialPersistentFields = {
571	>	new ObjectStreamField("segments", Segment[].class),
572	>	new ObjectStreamField("segmentMask", Integer.TYPE),
573	>	new ObjectStreamField("segmentShift", Integer.TYPE)
574	>	};
575	>
576	>	/* ---------------- Nodes -------------- */
577	>
578	>	/**
579	>	* Key-value entry.  This class is never exported out as a
580	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
581	>	* MapEntry below), but can be used for read-only traversals used
582	>	* in bulk tasks.  Subclasses of Node with a negative hash field
583	>	* are special, and contain null keys and values (but are never
584	>	* exported).  Otherwise, keys and vals are never null.
585		*/
586	<	static final class HashEntry<K,V> {
586	>	static class Node<K,V> implements Map.Entry<K,V> {
587		final int hash;
588		final K key;
589	<	volatile V value;
590	<	volatile HashEntry<K,V> next;
589	>	volatile V val;
590	>	volatile Node<K,V> next;
591
592	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
592	>	Node(int hash, K key, V val, Node<K,V> next) {
593		this.hash = hash;
594		this.key = key;
595	<	this.value = value;
595	>	this.val = val;
596		this.next = next;
597		}
598
599	+	public final K getKey()     { return key; }
600	+	public final V getValue()   { return val; }
601	+	public final int hashCode() { return key.hashCode() ^ val.hashCode(); }
602	+	public final String toString() {
603	+	return Helpers.mapEntryToString(key, val);
604	+	}
605	+	public final V setValue(V value) {
606	+	throw new UnsupportedOperationException();
607	+	}
608	+
609	+	public final boolean equals(Object o) {
610	+	Object k, v, u; Map.Entry<?,?> e;
611	+	return ((o instanceof Map.Entry) &&
612	+	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
613	+	(v = e.getValue()) != null &&
614	+	(k == key || k.equals(key)) &&
615	+	(v == (u = val) || v.equals(u)));
616	+	}
617	+
618		/**
619	<	* Sets next field with volatile write semantics.  (See above
190	<	* about use of putOrderedObject.)
619	>	* Virtualized support for map.get(); overridden in subclasses.
620		*/
621	<	final void setNext(HashEntry<K,V> n) {
622	<	UNSAFE.putOrderedObject(this, nextOffset, n);
621	>	Node<K,V> find(int h, Object k) {
622	>	Node<K,V> e = this;
623	>	if (k != null) {
624	>	do {
625	>	K ek;
626	>	if (e.hash == h &&
627	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
628	>	return e;
629	>	} while ((e = e.next) != null);
630	>	}
631	>	return null;
632		}
633	+	}
634
635	<	// Unsafe mechanics
636	<	static final sun.misc.Unsafe UNSAFE;
637	<	static final long nextOffset;
638	<	static {
639	<	try {
640	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
641	<	Class<?> k = HashEntry.class;
642	<	nextOffset = UNSAFE.objectFieldOffset
643	<	(k.getDeclaredField("next"));
644	<	} catch (Exception e) {
645	<	throw new Error(e);
635	>	/* ---------------- Static utilities -------------- */
636	>
637	>	/**
638	>	* Spreads (XORs) higher bits of hash to lower and also forces top
639	>	* bit to 0. Because the table uses power-of-two masking, sets of
640	>	* hashes that vary only in bits above the current mask will
641	>	* always collide. (Among known examples are sets of Float keys
642	>	* holding consecutive whole numbers in small tables.)  So we
643	>	* apply a transform that spreads the impact of higher bits
644	>	* downward. There is a tradeoff between speed, utility, and
645	>	* quality of bit-spreading. Because many common sets of hashes
646	>	* are already reasonably distributed (so don't benefit from
647	>	* spreading), and because we use trees to handle large sets of
648	>	* collisions in bins, we just XOR some shifted bits in the
649	>	* cheapest possible way to reduce systematic lossage, as well as
650	>	* to incorporate impact of the highest bits that would otherwise
651	>	* never be used in index calculations because of table bounds.
652	>	*/
653	>	static final int spread(int h) {
654	>	return (h ^ (h >>> 16)) & HASH_BITS;
655	>	}
656	>
657	>	/**
658	>	* Returns a power of two table size for the given desired capacity.
659	>	* See Hackers Delight, sec 3.2
660	>	*/
661	>	private static final int tableSizeFor(int c) {
662	>	int n = c - 1;
663	>	n |= n >>> 1;
664	>	n |= n >>> 2;
665	>	n |= n >>> 4;
666	>	n |= n >>> 8;
667	>	n |= n >>> 16;
668	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
669	>	}
670	>
671	>	/**
672	>	* Returns x's Class if it is of the form "class C implements
673	>	* Comparable<C>", else null.
674	>	*/
675	>	static Class<?> comparableClassFor(Object x) {
676	>	if (x instanceof Comparable) {
677	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
678	>	if ((c = x.getClass()) == String.class) // bypass checks
679	>	return c;
680	>	if ((ts = c.getGenericInterfaces()) != null) {
681	>	for (int i = 0; i < ts.length; ++i) {
682	>	if (((t = ts[i]) instanceof ParameterizedType) &&
683	>	((p = (ParameterizedType)t).getRawType() ==
684	>	Comparable.class) &&
685	>	(as = p.getActualTypeArguments()) != null &&
686	>	as.length == 1 && as[0] == c) // type arg is c
687	>	return c;
688	>	}
689		}
690		}
691	+	return null;
692		}
693
694		/**
695	<	* Gets the ith element of given table (if nonnull) with volatile
696	<	* read semantics. Note: This is manually integrated into a few
697	<	* performance-sensitive methods to reduce call overhead.
695	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
696	>	* class), else 0.
697	>	*/
698	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
699	>	static int compareComparables(Class<?> kc, Object k, Object x) {
700	>	return (x == null || x.getClass() != kc ? 0 :
701	>	((Comparable)k).compareTo(x));
702	>	}
703	>
704	>	/* ---------------- Table element access -------------- */
705	>
706	>	/*
707	>	* Volatile access methods are used for table elements as well as
708	>	* elements of in-progress next table while resizing.  All uses of
709	>	* the tab arguments must be null checked by callers.  All callers
710	>	* also paranoically precheck that tab's length is not zero (or an
711	>	* equivalent check), thus ensuring that any index argument taking
712	>	* the form of a hash value anded with (length - 1) is a valid
713	>	* index.  Note that, to be correct wrt arbitrary concurrency
714	>	* errors by users, these checks must operate on local variables,
715	>	* which accounts for some odd-looking inline assignments below.
716	>	* Note that calls to setTabAt always occur within locked regions,
717	>	* and so in principle require only release ordering, not
718	>	* full volatile semantics, but are currently coded as volatile
719	>	* writes to be conservative.
720		*/
721	+
722		@SuppressWarnings("unchecked")
723	<	static final <K,V> HashEntry<K,V> entryAt(HashEntry<K,V>[] tab, int i) {
724	<	return (tab == null) ? null :
725	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
726	<	(tab, ((long)i << TSHIFT) + TBASE);
723	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
724	>	return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
725	>	}
726	>
727	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
728	>	Node<K,V> c, Node<K,V> v) {
729	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
730		}
731
732	+	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
733	+	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
734	+	}
735	+
736	+	/* ---------------- Fields -------------- */
737	+
738	+	/**
739	+	* The array of bins. Lazily initialized upon first insertion.
740	+	* Size is always a power of two. Accessed directly by iterators.
741	+	*/
742	+	transient volatile Node<K,V>[] table;
743	+
744	+	/**
745	+	* The next table to use; non-null only while resizing.
746	+	*/
747	+	private transient volatile Node<K,V>[] nextTable;
748	+
749	+	/**
750	+	* Base counter value, used mainly when there is no contention,
751	+	* but also as a fallback during table initialization
752	+	* races. Updated via CAS.
753	+	*/
754	+	private transient volatile long baseCount;
755	+
756	+	/**
757	+	* Table initialization and resizing control.  When negative, the
758	+	* table is being initialized or resized: -1 for initialization,
759	+	* else -(1 + the number of active resizing threads).  Otherwise,
760	+	* when table is null, holds the initial table size to use upon
761	+	* creation, or 0 for default. After initialization, holds the
762	+	* next element count value upon which to resize the table.
763	+	*/
764	+	private transient volatile int sizeCtl;
765	+
766	+	/**
767	+	* The next table index (plus one) to split while resizing.
768	+	*/
769	+	private transient volatile int transferIndex;
770	+
771	+	/**
772	+	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
773	+	*/
774	+	private transient volatile int cellsBusy;
775	+
776	+	/**
777	+	* Table of counter cells. When non-null, size is a power of 2.
778	+	*/
779	+	private transient volatile CounterCell[] counterCells;
780	+
781	+	// views
782	+	private transient KeySetView<K,V> keySet;
783	+	private transient ValuesView<K,V> values;
784	+	private transient EntrySetView<K,V> entrySet;
785	+
786	+
787	+	/* ---------------- Public operations -------------- */
788	+
789		/**
790	<	* Sets the ith element of given table, with volatile write
225	<	* semantics. (See above about use of putOrderedObject.)
790	>	* Creates a new, empty map with the default initial table size (16).
791		*/
792	<	static final <K,V> void setEntryAt(HashEntry<K,V>[] tab, int i,
228	<	HashEntry<K,V> e) {
229	<	UNSAFE.putOrderedObject(tab, ((long)i << TSHIFT) + TBASE, e);
792	>	public ConcurrentHashMap() {
793		}
794
795		/**
796	<	* Applies a supplemental hash function to a given hashCode, which
797	<	* defends against poor quality hash functions.  This is critical
798	<	* because ConcurrentHashMap uses power-of-two length hash tables,
799	<	* that otherwise encounter collisions for hashCodes that do not
800	<	* differ in lower or upper bits.
796	>	* Creates a new, empty map with an initial table size
797	>	* accommodating the specified number of elements without the need
798	>	* to dynamically resize.
799	>	*
800	>	* @param initialCapacity The implementation performs internal
801	>	* sizing to accommodate this many elements.
802	>	* @throws IllegalArgumentException if the initial capacity of
803	>	* elements is negative
804		*/
805	<	private static int hash(int h) {
806	<	// Spread bits to regularize both segment and index locations,
807	<	// using variant of single-word Wang/Jenkins hash.
808	<	h += (h <<  15) ^ 0xffffcd7d;
809	<	h ^= (h >>> 10);
810	<	h += (h <<   3);
811	<	h ^= (h >>>  6);
246	<	h += (h <<   2) + (h << 14);
247	<	return h ^ (h >>> 16);
805	>	public ConcurrentHashMap(int initialCapacity) {
806	>	if (initialCapacity < 0)
807	>	throw new IllegalArgumentException();
808	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
809	>	MAXIMUM_CAPACITY :
810	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
811	>	this.sizeCtl = cap;
812		}
813
814		/**
815	<	* Segments are specialized versions of hash tables.  This
816	<	* subclasses from ReentrantLock opportunistically, just to
817	<	* simplify some locking and avoid separate construction.
815	>	* Creates a new map with the same mappings as the given map.
816	>	*
817	>	* @param m the map
818		*/
819	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
820	<	/*
821	<	* Segments maintain a table of entry lists that are always
822	<	* 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	<	*/
819	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
820	>	this.sizeCtl = DEFAULT_CAPACITY;
821	>	putAll(m);
822	>	}
823
824	<	private static final long serialVersionUID = 2249069246763182397L;
824	>	/**
825	>	* Creates a new, empty map with an initial table size based on
826	>	* the given number of elements ({@code initialCapacity}) and
827	>	* initial table density ({@code loadFactor}).
828	>	*
829	>	* @param initialCapacity the initial capacity. The implementation
830	>	* performs internal sizing to accommodate this many elements,
831	>	* given the specified load factor.
832	>	* @param loadFactor the load factor (table density) for
833	>	* establishing the initial table size
834	>	* @throws IllegalArgumentException if the initial capacity of
835	>	* elements is negative or the load factor is nonpositive
836	>	*
837	>	* @since 1.6
838	>	*/
839	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
840	>	this(initialCapacity, loadFactor, 1);
841	>	}
842
843	<	/**
844	<	* The maximum number of times to tryLock in a prescan before
845	<	* possibly blocking on acquire in preparation for a locked
846	<	* segment operation. On multiprocessors, using a bounded
847	<	* number of retries maintains cache acquired while locating
848	<	* nodes.
849	<	*/
850	<	static final int MAX_SCAN_RETRIES =
851	<	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
843	>	/**
844	>	* Creates a new, empty map with an initial table size based on
845	>	* the given number of elements ({@code initialCapacity}), table
846	>	* density ({@code loadFactor}), and number of concurrently
847	>	* updating threads ({@code concurrencyLevel}).
848	>	*
849	>	* @param initialCapacity the initial capacity. The implementation
850	>	* performs internal sizing to accommodate this many elements,
851	>	* given the specified load factor.
852	>	* @param loadFactor the load factor (table density) for
853	>	* establishing the initial table size
854	>	* @param concurrencyLevel the estimated number of concurrently
855	>	* updating threads. The implementation may use this value as
856	>	* a sizing hint.
857	>	* @throws IllegalArgumentException if the initial capacity is
858	>	* negative or the load factor or concurrencyLevel are
859	>	* nonpositive
860	>	*/
861	>	public ConcurrentHashMap(int initialCapacity,
862	>	float loadFactor, int concurrencyLevel) {
863	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
864	>	throw new IllegalArgumentException();
865	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
866	>	initialCapacity = concurrencyLevel;   // as estimated threads
867	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
868	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
869	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
870	>	this.sizeCtl = cap;
871	>	}
872
873	<	/**
295	<	* The per-segment table. Elements are accessed via
296	<	* entryAt/setEntryAt providing volatile semantics.
297	<	*/
298	<	transient volatile HashEntry<K,V>[] table;
873	>	// Original (since JDK1.2) Map methods
874
875	<	/**
876	<	* The number of elements. Accessed only either within locks
877	<	* or among other volatile reads that maintain visibility.
878	<	*/
879	<	transient int count;
875	>	/**
876	>	* {@inheritDoc}
877	>	*/
878	>	public int size() {
879	>	long n = sumCount();
880	>	return ((n < 0L) ? 0 :
881	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
882	>	(int)n);
883	>	}
884
885	<	/**
886	<	* The total number of mutative operations in this segment.
887	<	* Even though this may overflows 32 bits, it provides
888	<	* sufficient accuracy for stability checks in CHM isEmpty()
889	<	* and size() methods.  Accessed only either within locks or
890	<	* among other volatile reads that maintain visibility.
312	<	*/
313	<	transient int modCount;
885	>	/**
886	>	* {@inheritDoc}
887	>	*/
888	>	public boolean isEmpty() {
889	>	return sumCount() <= 0L; // ignore transient negative values
890	>	}
891
892	<	/**
893	<	* The table is rehashed when its size exceeds this threshold.
894	<	* (The value of this field is always <tt>(int)(capacity *
895	<	* loadFactor)</tt>.)
896	<	*/
897	<	transient int threshold;
892	>	/**
893	>	* Returns the value to which the specified key is mapped,
894	>	* or {@code null} if this map contains no mapping for the key.
895	>	*
896	>	* <p>More formally, if this map contains a mapping from a key
897	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
898	>	* then this method returns {@code v}; otherwise it returns
899	>	* {@code null}.  (There can be at most one such mapping.)
900	>	*
901	>	* @throws NullPointerException if the specified key is null
902	>	*/
903	>	public V get(Object key) {
904	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
905	>	int h = spread(key.hashCode());
906	>	if ((tab = table) != null && (n = tab.length) > 0 &&
907	>	(e = tabAt(tab, (n - 1) & h)) != null) {
908	>	if ((eh = e.hash) == h) {
909	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
910	>	return e.val;
911	>	}
912	>	else if (eh < 0)
913	>	return (p = e.find(h, key)) != null ? p.val : null;
914	>	while ((e = e.next) != null) {
915	>	if (e.hash == h &&
916	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
917	>	return e.val;
918	>	}
919	>	}
920	>	return null;
921	>	}
922
923	<	/**
924	<	* The load factor for the hash table.  Even though this value
925	<	* is same for all segments, it is replicated to avoid needing
926	<	* links to outer object.
927	<	* @serial
928	<	*/
929	<	final float loadFactor;
923	>	/**
924	>	* Tests if the specified object is a key in this table.
925	>	*
926	>	* @param  key possible key
927	>	* @return {@code true} if and only if the specified object
928	>	*         is a key in this table, as determined by the
929	>	*         {@code equals} method; {@code false} otherwise
930	>	* @throws NullPointerException if the specified key is null
931	>	*/
932	>	public boolean containsKey(Object key) {
933	>	return get(key) != null;
934	>	}
935
936	<	Segment(float lf, int threshold, HashEntry<K,V>[] tab) {
937	<	this.loadFactor = lf;
938	<	this.threshold = threshold;
939	<	this.table = tab;
936	>	/**
937	>	* Returns {@code true} if this map maps one or more keys to the
938	>	* specified value. Note: This method may require a full traversal
939	>	* of the map, and is much slower than method {@code containsKey}.
940	>	*
941	>	* @param value value whose presence in this map is to be tested
942	>	* @return {@code true} if this map maps one or more keys to the
943	>	*         specified value
944	>	* @throws NullPointerException if the specified value is null
945	>	*/
946	>	public boolean containsValue(Object value) {
947	>	if (value == null)
948	>	throw new NullPointerException();
949	>	Node<K,V>[] t;
950	>	if ((t = table) != null) {
951	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
952	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
953	>	V v;
954	>	if ((v = p.val) == value || (v != null && value.equals(v)))
955	>	return true;
956	>	}
957		}
958	+	return false;
959	+	}
960
961	<	final V put(K key, int hash, V value, boolean onlyIfAbsent) {
962	<	HashEntry<K,V> node = tryLock() ? null :
963	<	scanAndLockForPut(key, hash, value);
964	<	V oldValue;
965	<	try {
966	<	HashEntry<K,V>[] tab = table;
967	<	int index = (tab.length - 1) & hash;
968	<	HashEntry<K,V> first = entryAt(tab, index);
969	<	for (HashEntry<K,V> e = first;;) {
970	<	if (e != null) {
971	<	K k;
972	<	if ((k = e.key) == key ||
973	<	(e.hash == hash && key.equals(k))) {
974	<	oldValue = e.value;
975	<	if (!onlyIfAbsent) {
976	<	e.value = value;
977	<	++modCount;
961	>	/**
962	>	* Maps the specified key to the specified value in this table.
963	>	* Neither the key nor the value can be null.
964	>	*
965	>	* <p>The value can be retrieved by calling the {@code get} method
966	>	* with a key that is equal to the original key.
967	>	*
968	>	* @param key key with which the specified value is to be associated
969	>	* @param value value to be associated with the specified key
970	>	* @return the previous value associated with {@code key}, or
971	>	*         {@code null} if there was no mapping for {@code key}
972	>	* @throws NullPointerException if the specified key or value is null
973	>	*/
974	>	public V put(K key, V value) {
975	>	return putVal(key, value, false);
976	>	}
977	>
978	>	/** Implementation for put and putIfAbsent */
979	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
980	>	if (key == null || value == null) throw new NullPointerException();
981	>	int hash = spread(key.hashCode());
982	>	int binCount = 0;
983	>	for (Node<K,V>[] tab = table;;) {
984	>	Node<K,V> f; int n, i, fh;
985	>	if (tab == null || (n = tab.length) == 0)
986	>	tab = initTable();
987	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
988	>	if (casTabAt(tab, i, null,
989	>	new Node<K,V>(hash, key, value, null)))
990	>	break;                   // no lock when adding to empty bin
991	>	}
992	>	else if ((fh = f.hash) == MOVED)
993	>	tab = helpTransfer(tab, f);
994	>	else {
995	>	V oldVal = null;
996	>	synchronized (f) {
997	>	if (tabAt(tab, i) == f) {
998	>	if (fh >= 0) {
999	>	binCount = 1;
1000	>	for (Node<K,V> e = f;; ++binCount) {
1001	>	K ek;
1002	>	if (e.hash == hash &&
1003	>	((ek = e.key) == key ||
1004	>	(ek != null && key.equals(ek)))) {
1005	>	oldVal = e.val;
1006	>	if (!onlyIfAbsent)
1007	>	e.val = value;
1008	>	break;
1009	>	}
1010	>	Node<K,V> pred = e;
1011	>	if ((e = e.next) == null) {
1012	>	pred.next = new Node<K,V>(hash, key,
1013	>	value, null);
1014	>	break;
1015	>	}
1016		}
354	–	break;
1017		}
1018	<	e = e.next;
1019	<	}
1020	<	else {
1021	<	if (node != null)
1022	<	node.setNext(first);
1023	<	else
1024	<	node = new HashEntry<K,V>(hash, key, value, first);
1025	<	int c = count + 1;
1026	<	if (c > threshold && tab.length < MAXIMUM_CAPACITY)
1027	<	rehash(node);
1028	<	else
1029	<	setEntryAt(tab, index, node);
368	<	++modCount;
369	<	count = c;
370	<	oldValue = null;
371	<	break;
372	<	}
373	<	}
374	<	} finally {
375	<	unlock();
376	<	}
377	<	return oldValue;
378	<	}
379	<
380	<	/**
381	<	* Doubles size of table and repacks entries, also adding the
382	<	* given node to new table
383	<	*/
384	<	@SuppressWarnings("unchecked")
385	<	private void rehash(HashEntry<K,V> node) {
386	<	/*
387	<	* Reclassify nodes in each list to new table.  Because we
388	<	* are using power-of-two expansion, the elements from
389	<	* each bin must either stay at same index, or move with a
390	<	* power of two offset. We eliminate unnecessary node
391	<	* creation by catching cases where old nodes can be
392	<	* reused because their next fields won't change.
393	<	* Statistically, at the default threshold, only about
394	<	* one-sixth of them need cloning when a table
395	<	* doubles. The nodes they replace will be garbage
396	<	* collectable as soon as they are no longer referenced by
397	<	* any reader thread that may be in the midst of
398	<	* concurrently traversing table. Entry accesses use plain
399	<	* array indexing because they are followed by volatile
400	<	* table write.
401	<	*/
402	<	HashEntry<K,V>[] oldTable = table;
403	<	int oldCapacity = oldTable.length;
404	<	int newCapacity = oldCapacity << 1;
405	<	threshold = (int)(newCapacity * loadFactor);
406	<	HashEntry<K,V>[] newTable =
407	<	(HashEntry<K,V>[]) new HashEntry<?,?>[newCapacity];
408	<	int sizeMask = newCapacity - 1;
409	<	for (int i = 0; i < oldCapacity ; i++) {
410	<	HashEntry<K,V> e = oldTable[i];
411	<	if (e != null) {
412	<	HashEntry<K,V> next = e.next;
413	<	int idx = e.hash & sizeMask;
414	<	if (next == null)   //  Single node on list
415	<	newTable[idx] = e;
416	<	else { // Reuse consecutive sequence at same slot
417	<	HashEntry<K,V> lastRun = e;
418	<	int lastIdx = idx;
419	<	for (HashEntry<K,V> last = next;
420	<	last != null;
421	<	last = last.next) {
422	<	int k = last.hash & sizeMask;
423	<	if (k != lastIdx) {
424	<	lastIdx = k;
425	<	lastRun = last;
426	<	}
427	<	}
428	<	newTable[lastIdx] = lastRun;
429	<	// Clone remaining nodes
430	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
431	<	V v = p.value;
432	<	int h = p.hash;
433	<	int k = h & sizeMask;
434	<	HashEntry<K,V> n = newTable[k];
435	<	newTable[k] = new HashEntry<K,V>(h, p.key, v, n);
436	<	}
437	<	}
438	<	}
439	<	}
440	<	int nodeIndex = node.hash & sizeMask; // add the new node
441	<	node.setNext(newTable[nodeIndex]);
442	<	newTable[nodeIndex] = node;
443	<	table = newTable;
444	<	}
445	<
446	<	/**
447	<	* Scans for a node containing given key while trying to
448	<	* acquire lock, creating and returning one if not found. Upon
449	<	* return, guarantees that lock is held. Unlike in most
450	<	* methods, calls to method equals are not screened: Since
451	<	* traversal speed doesn't matter, we might as well help warm
452	<	* up the associated code and accesses as well.
453	<	*
454	<	* @return a new node if key not found, else null
455	<	*/
456	<	private HashEntry<K,V> scanAndLockForPut(K key, int hash, V value) {
457	<	HashEntry<K,V> first = entryForHash(this, hash);
458	<	HashEntry<K,V> e = first;
459	<	HashEntry<K,V> node = null;
460	<	int retries = -1; // negative while locating node
461	<	while (!tryLock()) {
462	<	HashEntry<K,V> f; // to recheck first below
463	<	if (retries < 0) {
464	<	if (e == null) {
465	<	if (node == null) // speculatively create node
466	<	node = new HashEntry<K,V>(hash, key, value, null);
467	<	retries = 0;
1018	>	else if (f instanceof TreeBin) {
1019	>	Node<K,V> p;
1020	>	binCount = 2;
1021	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1022	>	value)) != null) {
1023	>	oldVal = p.val;
1024	>	if (!onlyIfAbsent)
1025	>	p.val = value;
1026	>	}
1027	>	}
1028	>	else if (f instanceof ReservationNode)
1029	>	throw new IllegalStateException("Recursive update");
1030		}
469	–	else if (key.equals(e.key))
470	–	retries = 0;
471	–	else
472	–	e = e.next;
1031		}
1032	<	else if (++retries > MAX_SCAN_RETRIES) {
1033	<	lock();
1032	>	if (binCount != 0) {
1033	>	if (binCount >= TREEIFY_THRESHOLD)
1034	>	treeifyBin(tab, i);
1035	>	if (oldVal != null)
1036	>	return oldVal;
1037		break;
1038		}
478	–	else if ((retries & 1) == 0 &&
479	–	(f = entryForHash(this, hash)) != first) {
480	–	e = first = f; // re-traverse if entry changed
481	–	retries = -1;
482	–	}
483	–	}
484	–	return node;
485	–	}
486	–
487	–	/**
488	–	* Scans for a node containing the given key while trying to
489	–	* acquire lock for a remove or replace operation. Upon
490	–	* return, guarantees that lock is held.  Note that we must
491	–	* lock even if the key is not found, to ensure sequential
492	–	* consistency of updates.
493	–	*/
494	–	private void scanAndLock(Object key, int hash) {
495	–	// similar to but simpler than scanAndLockForPut
496	–	HashEntry<K,V> first = entryForHash(this, hash);
497	–	HashEntry<K,V> e = first;
498	–	int retries = -1;
499	–	while (!tryLock()) {
500	–	HashEntry<K,V> f;
501	–	if (retries < 0) {
502	–	if (e == null || key.equals(e.key))
503	–	retries = 0;
504	–	else
505	–	e = e.next;
506	–	}
507	–	else if (++retries > MAX_SCAN_RETRIES) {
508	–	lock();
509	–	break;
510	–	}
511	–	else if ((retries & 1) == 0 &&
512	–	(f = entryForHash(this, hash)) != first) {
513	–	e = first = f;
514	–	retries = -1;
515	–	}
1039		}
1040		}
1041	+	addCount(1L, binCount);
1042	+	return null;
1043	+	}
1044
1045	<	/**
1046	<	* Remove; match on key only if value null, else match both.
1047	<	*/
1048	<	final V remove(Object key, int hash, Object value) {
1049	<	if (!tryLock())
1050	<	scanAndLock(key, hash);
1051	<	V oldValue = null;
1052	<	try {
1053	<	HashEntry<K,V>[] tab = table;
1054	<	int index = (tab.length - 1) & hash;
1055	<	HashEntry<K,V> e = entryAt(tab, index);
1056	<	HashEntry<K,V> pred = null;
1057	<	while (e != null) {
1058	<	K k;
1059	<	HashEntry<K,V> next = e.next;
1060	<	if ((k = e.key) == key ||
1061	<	(e.hash == hash && key.equals(k))) {
1062	<	V v = e.value;
1063	<	if (value == null || value == v || value.equals(v)) {
1064	<	if (pred == null)
1065	<	setEntryAt(tab, index, next);
1066	<	else
1067	<	pred.setNext(next);
1068	<	++modCount;
1069	<	--count;
1070	<	oldValue = v;
1045	>	/**
1046	>	* Copies all of the mappings from the specified map to this one.
1047	>	* These mappings replace any mappings that this map had for any of the
1048	>	* keys currently in the specified map.
1049	>	*
1050	>	* @param m mappings to be stored in this map
1051	>	*/
1052	>	public void putAll(Map<? extends K, ? extends V> m) {
1053	>	tryPresize(m.size());
1054	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1055	>	putVal(e.getKey(), e.getValue(), false);
1056	>	}
1057	>
1058	>	/**
1059	>	* Removes the key (and its corresponding value) from this map.
1060	>	* This method does nothing if the key is not in the map.
1061	>	*
1062	>	* @param  key the key that needs to be removed
1063	>	* @return the previous value associated with {@code key}, or
1064	>	*         {@code null} if there was no mapping for {@code key}
1065	>	* @throws NullPointerException if the specified key is null
1066	>	*/
1067	>	public V remove(Object key) {
1068	>	return replaceNode(key, null, null);
1069	>	}
1070	>
1071	>	/**
1072	>	* Implementation for the four public remove/replace methods:
1073	>	* Replaces node value with v, conditional upon match of cv if
1074	>	* non-null.  If resulting value is null, delete.
1075	>	*/
1076	>	final V replaceNode(Object key, V value, Object cv) {
1077	>	int hash = spread(key.hashCode());
1078	>	for (Node<K,V>[] tab = table;;) {
1079	>	Node<K,V> f; int n, i, fh;
1080	>	if (tab == null || (n = tab.length) == 0 ||
1081	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1082	>	break;
1083	>	else if ((fh = f.hash) == MOVED)
1084	>	tab = helpTransfer(tab, f);
1085	>	else {
1086	>	V oldVal = null;
1087	>	boolean validated = false;
1088	>	synchronized (f) {
1089	>	if (tabAt(tab, i) == f) {
1090	>	if (fh >= 0) {
1091	>	validated = true;
1092	>	for (Node<K,V> e = f, pred = null;;) {
1093	>	K ek;
1094	>	if (e.hash == hash &&
1095	>	((ek = e.key) == key ||
1096	>	(ek != null && key.equals(ek)))) {
1097	>	V ev = e.val;
1098	>	if (cv == null || cv == ev ||
1099	>	(ev != null && cv.equals(ev))) {
1100	>	oldVal = ev;
1101	>	if (value != null)
1102	>	e.val = value;
1103	>	else if (pred != null)
1104	>	pred.next = e.next;
1105	>	else
1106	>	setTabAt(tab, i, e.next);
1107	>	}
1108	>	break;
1109	>	}
1110	>	pred = e;
1111	>	if ((e = e.next) == null)
1112	>	break;
1113	>	}
1114		}
1115	<	break;
1115	>	else if (f instanceof TreeBin) {
1116	>	validated = true;
1117	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1118	>	TreeNode<K,V> r, p;
1119	>	if ((r = t.root) != null &&
1120	>	(p = r.findTreeNode(hash, key, null)) != null) {
1121	>	V pv = p.val;
1122	>	if (cv == null || cv == pv ||
1123	>	(pv != null && cv.equals(pv))) {
1124	>	oldVal = pv;
1125	>	if (value != null)
1126	>	p.val = value;
1127	>	else if (t.removeTreeNode(p))
1128	>	setTabAt(tab, i, untreeify(t.first));
1129	>	}
1130	>	}
1131	>	}
1132	>	else if (f instanceof ReservationNode)
1133	>	throw new IllegalStateException("Recursive update");
1134		}
548	–	pred = e;
549	–	e = next;
1135		}
1136	<	} finally {
1137	<	unlock();
1138	<	}
1139	<	return oldValue;
1140	<	}
556	<
557	<	final boolean replace(K key, int hash, V oldValue, V newValue) {
558	<	if (!tryLock())
559	<	scanAndLock(key, hash);
560	<	boolean replaced = false;
561	<	try {
562	<	HashEntry<K,V> e;
563	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
564	<	K k;
565	<	if ((k = e.key) == key ||
566	<	(e.hash == hash && key.equals(k))) {
567	<	if (oldValue.equals(e.value)) {
568	<	e.value = newValue;
569	<	++modCount;
570	<	replaced = true;
571	<	}
572	<	break;
1136	>	if (validated) {
1137	>	if (oldVal != null) {
1138	>	if (value == null)
1139	>	addCount(-1L, -1);
1140	>	return oldVal;
1141		}
1142	+	break;
1143		}
575	–	} finally {
576	–	unlock();
1144		}
578	–	return replaced;
1145		}
1146	+	return null;
1147	+	}
1148
1149	<	final V replace(K key, int hash, V value) {
1150	<	if (!tryLock())
1151	<	scanAndLock(key, hash);
1152	<	V oldValue = null;
1153	<	try {
1154	<	HashEntry<K,V> e;
1155	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1156	<	K k;
1157	<	if ((k = e.key) == key ||
1158	<	(e.hash == hash && key.equals(k))) {
1159	<	oldValue = e.value;
1160	<	e.value = value;
1161	<	++modCount;
1162	<	break;
1149	>	/**
1150	>	* Removes all of the mappings from this map.
1151	>	*/
1152	>	public void clear() {
1153	>	long delta = 0L; // negative number of deletions
1154	>	int i = 0;
1155	>	Node<K,V>[] tab = table;
1156	>	while (tab != null && i < tab.length) {
1157	>	int fh;
1158	>	Node<K,V> f = tabAt(tab, i);
1159	>	if (f == null)
1160	>	++i;
1161	>	else if ((fh = f.hash) == MOVED) {
1162	>	tab = helpTransfer(tab, f);
1163	>	i = 0; // restart
1164	>	}
1165	>	else {
1166	>	synchronized (f) {
1167	>	if (tabAt(tab, i) == f) {
1168	>	Node<K,V> p = (fh >= 0 ? f :
1169	>	(f instanceof TreeBin) ?
1170	>	((TreeBin<K,V>)f).first : null);
1171	>	while (p != null) {
1172	>	--delta;
1173	>	p = p.next;
1174	>	}
1175	>	setTabAt(tab, i++, null);
1176		}
1177		}
597	–	} finally {
598	–	unlock();
1178		}
600	–	return oldValue;
1179		}
1180	+	if (delta != 0L)
1181	+	addCount(delta, -1);
1182	+	}
1183
1184	<	final void clear() {
1185	<	lock();
1186	<	try {
1187	<	HashEntry<K,V>[] tab = table;
1188	<	for (int i = 0; i < tab.length ; i++)
1189	<	setEntryAt(tab, i, null);
1190	<	++modCount;
1191	<	count = 0;
1192	<	} finally {
1193	<	unlock();
1194	<	}
1195	<	}
1184	>	/**
1185	>	* Returns a {@link Set} view of the keys contained in this map.
1186	>	* The set is backed by the map, so changes to the map are
1187	>	* reflected in the set, and vice-versa. The set supports element
1188	>	* removal, which removes the corresponding mapping from this map,
1189	>	* via the {@code Iterator.remove}, {@code Set.remove},
1190	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1191	>	* operations.  It does not support the {@code add} or
1192	>	* {@code addAll} operations.
1193	>	*
1194	>	* <p>The view's iterators and spliterators are
1195	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1196	>	*
1197	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1198	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1199	>	*
1200	>	* @return the set view
1201	>	*/
1202	>	public KeySetView<K,V> keySet() {
1203	>	KeySetView<K,V> ks;
1204	>	return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null));
1205	>	}
1206	>
1207	>	/**
1208	>	* Returns a {@link Collection} view of the values contained in this map.
1209	>	* The collection is backed by the map, so changes to the map are
1210	>	* reflected in the collection, and vice-versa.  The collection
1211	>	* supports element removal, which removes the corresponding
1212	>	* mapping from this map, via the {@code Iterator.remove},
1213	>	* {@code Collection.remove}, {@code removeAll},
1214	>	* {@code retainAll}, and {@code clear} operations.  It does not
1215	>	* support the {@code add} or {@code addAll} operations.
1216	>	*
1217	>	* <p>The view's iterators and spliterators are
1218	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1219	>	*
1220	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1221	>	* and {@link Spliterator#NONNULL}.
1222	>	*
1223	>	* @return the collection view
1224	>	*/
1225	>	public Collection<V> values() {
1226	>	ValuesView<K,V> vs;
1227	>	return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this));
1228		}
1229
1230	<	// Accessing segments
1230	>	/**
1231	>	* Returns a {@link Set} view of the mappings contained in this map.
1232	>	* The set is backed by the map, so changes to the map are
1233	>	* reflected in the set, and vice-versa.  The set supports element
1234	>	* removal, which removes the corresponding mapping from the map,
1235	>	* via the {@code Iterator.remove}, {@code Set.remove},
1236	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1237	>	* operations.
1238	>	*
1239	>	* <p>The view's iterators and spliterators are
1240	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1241	>	*
1242	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1243	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1244	>	*
1245	>	* @return the set view
1246	>	*/
1247	>	public Set<Map.Entry<K,V>> entrySet() {
1248	>	EntrySetView<K,V> es;
1249	>	return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this));
1250	>	}
1251
1252		/**
1253	<	* Gets the jth element of given segment array (if nonnull) with
1254	<	* volatile element access semantics via Unsafe. (The null check
1255	<	* can trigger harmlessly only during deserialization.) Note:
1256	<	* because each element of segments array is set only once (using
1257	<	* fully ordered writes), some performance-sensitive methods rely
625	<	* on this method only as a recheck upon null reads.
1253	>	* Returns the hash code value for this {@link Map}, i.e.,
1254	>	* the sum of, for each key-value pair in the map,
1255	>	* {@code key.hashCode() ^ value.hashCode()}.
1256	>	*
1257	>	* @return the hash code value for this map
1258		*/
1259	<	@SuppressWarnings("unchecked")
1260	<	static final <K,V> Segment<K,V> segmentAt(Segment<K,V>[] ss, int j) {
1261	<	long u = (j << SSHIFT) + SBASE;
1262	<	return ss == null ? null :
1263	<	(Segment<K,V>) UNSAFE.getObjectVolatile(ss, u);
1259	>	public int hashCode() {
1260	>	int h = 0;
1261	>	Node<K,V>[] t;
1262	>	if ((t = table) != null) {
1263	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1264	>	for (Node<K,V> p; (p = it.advance()) != null; )
1265	>	h += p.key.hashCode() ^ p.val.hashCode();
1266	>	}
1267	>	return h;
1268		}
1269
1270		/**
1271	<	* Returns the segment for the given index, creating it and
1272	<	* recording in segment table (via CAS) if not already present.
1271	>	* Returns a string representation of this map.  The string
1272	>	* representation consists of a list of key-value mappings (in no
1273	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1274	>	* mappings are separated by the characters {@code ", "} (comma
1275	>	* and space).  Each key-value mapping is rendered as the key
1276	>	* followed by an equals sign ("{@code =}") followed by the
1277	>	* associated value.
1278		*
1279	<	* @param k the index
639	<	* @return the segment
1279	>	* @return a string representation of this map
1280		*/
1281	<	@SuppressWarnings("unchecked")
1282	<	private Segment<K,V> ensureSegment(int k) {
1283	<	final Segment<K,V>[] ss = this.segments;
1284	<	long u = (k << SSHIFT) + SBASE; // raw offset
1285	<	Segment<K,V> seg;
1286	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u)) == null) {
1287	<	Segment<K,V> proto = ss[0]; // use segment 0 as prototype
1288	<	int cap = proto.table.length;
1289	<	float lf = proto.loadFactor;
1290	<	int threshold = (int)(cap * lf);
1291	<	HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry<?,?>[cap];
1292	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
1293	<	== null) { // recheck
1294	<	Segment<K,V> s = new Segment<K,V>(lf, threshold, tab);
1295	<	while ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
1296	<	== null) {
1297	<	if (UNSAFE.compareAndSwapObject(ss, u, null, seg = s))
658	<	break;
659	<	}
1281	>	public String toString() {
1282	>	Node<K,V>[] t;
1283	>	int f = (t = table) == null ? 0 : t.length;
1284	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1285	>	StringBuilder sb = new StringBuilder();
1286	>	sb.append('{');
1287	>	Node<K,V> p;
1288	>	if ((p = it.advance()) != null) {
1289	>	for (;;) {
1290	>	K k = p.key;
1291	>	V v = p.val;
1292	>	sb.append(k == this ? "(this Map)" : k);
1293	>	sb.append('=');
1294	>	sb.append(v == this ? "(this Map)" : v);
1295	>	if ((p = it.advance()) == null)
1296	>	break;
1297	>	sb.append(',').append(' ');
1298		}
1299		}
1300	<	return seg;
1300	>	return sb.append('}').toString();
1301		}
1302
665	–	// Hash-based segment and entry accesses
666	–
1303		/**
1304	<	* Gets the segment for the given hash code.
1304	>	* Compares the specified object with this map for equality.
1305	>	* Returns {@code true} if the given object is a map with the same
1306	>	* mappings as this map.  This operation may return misleading
1307	>	* results if either map is concurrently modified during execution
1308	>	* of this method.
1309	>	*
1310	>	* @param o object to be compared for equality with this map
1311	>	* @return {@code true} if the specified object is equal to this map
1312		*/
1313	<	@SuppressWarnings("unchecked")
1314	<	private Segment<K,V> segmentForHash(int h) {
1315	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
1316	<	return (Segment<K,V>) UNSAFE.getObjectVolatile(segments, u);
1313	>	public boolean equals(Object o) {
1314	>	if (o != this) {
1315	>	if (!(o instanceof Map))
1316	>	return false;
1317	>	Map<?,?> m = (Map<?,?>) o;
1318	>	Node<K,V>[] t;
1319	>	int f = (t = table) == null ? 0 : t.length;
1320	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1321	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1322	>	V val = p.val;
1323	>	Object v = m.get(p.key);
1324	>	if (v == null || (v != val && !v.equals(val)))
1325	>	return false;
1326	>	}
1327	>	for (Map.Entry<?,?> e : m.entrySet()) {
1328	>	Object mk, mv, v;
1329	>	if ((mk = e.getKey()) == null ||
1330	>	(mv = e.getValue()) == null ||
1331	>	(v = get(mk)) == null ||
1332	>	(mv != v && !mv.equals(v)))
1333	>	return false;
1334	>	}
1335	>	}
1336	>	return true;
1337		}
1338
1339		/**
1340	<	* Gets the table entry for the given segment and hash code.
1340	>	* Stripped-down version of helper class used in previous version,
1341	>	* declared for the sake of serialization compatibility
1342		*/
1343	<	@SuppressWarnings("unchecked")
1344	<	static final <K,V> HashEntry<K,V> entryForHash(Segment<K,V> seg, int h) {
1345	<	HashEntry<K,V>[] tab;
1346	<	return (seg == null || (tab = seg.table) == null) ? null :
683	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
684	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
1343	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1344	>	private static final long serialVersionUID = 2249069246763182397L;
1345	>	final float loadFactor;
1346	>	Segment(float lf) { this.loadFactor = lf; }
1347		}
1348
687	–	/* ---------------- Public operations -------------- */
688	–
1349		/**
1350	<	* Creates a new, empty map with the specified initial
1351	<	* capacity, load factor and concurrency level.
1352	<	*
1353	<	* @param initialCapacity the initial capacity. The implementation
1354	<	* performs internal sizing to accommodate this many elements.
1355	<	* @param loadFactor  the load factor threshold, used to control resizing.
1356	<	* Resizing may be performed when the average number of elements per
1357	<	* 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.
1350	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
1351	>	* stream (i.e., serializes it).
1352	>	* @param s the stream
1353	>	* @throws java.io.IOException if an I/O error occurs
1354	>	* @serialData
1355	>	* the key (Object) and value (Object)
1356	>	* for each key-value mapping, followed by a null pair.
1357	>	* The key-value mappings are emitted in no particular order.
1358		*/
1359	<	@SuppressWarnings("unchecked")
1360	<	public ConcurrentHashMap(int initialCapacity,
1361	<	float loadFactor, int concurrencyLevel) {
1362	<	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
1359	>	private void writeObject(java.io.ObjectOutputStream s)
1360	>	throws java.io.IOException {
1361	>	// For serialization compatibility
1362	>	// Emulate segment calculation from previous version of this class
1363		int sshift = 0;
1364		int ssize = 1;
1365	<	while (ssize < concurrencyLevel) {
1365	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1366		++sshift;
1367		ssize <<= 1;
1368		}
1369	<	this.segmentShift = 32 - sshift;
1370	<	this.segmentMask = ssize - 1;
1371	<	if (initialCapacity > MAXIMUM_CAPACITY)
1372	<	initialCapacity = MAXIMUM_CAPACITY;
1373	<	int c = initialCapacity / ssize;
1374	<	if (c * ssize < initialCapacity)
1375	<	++c;
1376	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
1377	<	while (cap < c)
1378	<	cap <<= 1;
1379	<	// create segments and segments[0]
1380	<	Segment<K,V> s0 =
1381	<	new Segment<K,V>(loadFactor, (int)(cap * loadFactor),
1382	<	(HashEntry<K,V>[])new HashEntry<?,?>[cap]);
1383	<	Segment<K,V>[] ss = (Segment<K,V>[])new Segment<?,?>[ssize];
1384	<	UNSAFE.putOrderedObject(ss, SBASE, s0); // ordered write of segments[0]
1385	<	this.segments = ss;
1369	>	int segmentShift = 32 - sshift;
1370	>	int segmentMask = ssize - 1;
1371	>	@SuppressWarnings("unchecked")
1372	>	Segment<K,V>[] segments = (Segment<K,V>[])
1373	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1374	>	for (int i = 0; i < segments.length; ++i)
1375	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1376	>	s.putFields().put("segments", segments);
1377	>	s.putFields().put("segmentShift", segmentShift);
1378	>	s.putFields().put("segmentMask", segmentMask);
1379	>	s.writeFields();
1380	>
1381	>	Node<K,V>[] t;
1382	>	if ((t = table) != null) {
1383	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1384	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1385	>	s.writeObject(p.key);
1386	>	s.writeObject(p.val);
1387	>	}
1388	>	}
1389	>	s.writeObject(null);
1390	>	s.writeObject(null);
1391	>	segments = null; // throw away
1392		}
1393
1394		/**
1395	<	* Creates a new, empty map with the specified initial capacity
1396	<	* and load factor and with the default concurrencyLevel (16).
1397	<	*
1398	<	* @param initialCapacity The implementation performs internal
1399	<	* sizing to accommodate this many elements.
1400	<	* @param loadFactor  the load factor threshold, used to control resizing.
1401	<	* Resizing may be performed when the average number of elements per
1402	<	* bin exceeds this threshold.
1403	<	* @throws IllegalArgumentException if the initial capacity of
1404	<	* elements is negative or the load factor is nonpositive
1395	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1396	>	* @param s the stream
1397	>	* @throws ClassNotFoundException if the class of a serialized object
1398	>	*         could not be found
1399	>	* @throws java.io.IOException if an I/O error occurs
1400	>	*/
1401	>	private void readObject(java.io.ObjectInputStream s)
1402	>	throws java.io.IOException, ClassNotFoundException {
1403	>	/*
1404	>	* To improve performance in typical cases, we create nodes
1405	>	* while reading, then place in table once size is known.
1406	>	* However, we must also validate uniqueness and deal with
1407	>	* overpopulated bins while doing so, which requires
1408	>	* specialized versions of putVal mechanics.
1409	>	*/
1410	>	sizeCtl = -1; // force exclusion for table construction
1411	>	s.defaultReadObject();
1412	>	long size = 0L;
1413	>	Node<K,V> p = null;
1414	>	for (;;) {
1415	>	@SuppressWarnings("unchecked")
1416	>	K k = (K) s.readObject();
1417	>	@SuppressWarnings("unchecked")
1418	>	V v = (V) s.readObject();
1419	>	if (k != null && v != null) {
1420	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1421	>	++size;
1422	>	}
1423	>	else
1424	>	break;
1425	>	}
1426	>	if (size == 0L)
1427	>	sizeCtl = 0;
1428	>	else {
1429	>	int n;
1430	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1431	>	n = MAXIMUM_CAPACITY;
1432	>	else {
1433	>	int sz = (int)size;
1434	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
1435	>	}
1436	>	@SuppressWarnings("unchecked")
1437	>	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1438	>	int mask = n - 1;
1439	>	long added = 0L;
1440	>	while (p != null) {
1441	>	boolean insertAtFront;
1442	>	Node<K,V> next = p.next, first;
1443	>	int h = p.hash, j = h & mask;
1444	>	if ((first = tabAt(tab, j)) == null)
1445	>	insertAtFront = true;
1446	>	else {
1447	>	K k = p.key;
1448	>	if (first.hash < 0) {
1449	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1450	>	if (t.putTreeVal(h, k, p.val) == null)
1451	>	++added;
1452	>	insertAtFront = false;
1453	>	}
1454	>	else {
1455	>	int binCount = 0;
1456	>	insertAtFront = true;
1457	>	Node<K,V> q; K qk;
1458	>	for (q = first; q != null; q = q.next) {
1459	>	if (q.hash == h &&
1460	>	((qk = q.key) == k ||
1461	>	(qk != null && k.equals(qk)))) {
1462	>	insertAtFront = false;
1463	>	break;
1464	>	}
1465	>	++binCount;
1466	>	}
1467	>	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1468	>	insertAtFront = false;
1469	>	++added;
1470	>	p.next = first;
1471	>	TreeNode<K,V> hd = null, tl = null;
1472	>	for (q = p; q != null; q = q.next) {
1473	>	TreeNode<K,V> t = new TreeNode<K,V>
1474	>	(q.hash, q.key, q.val, null, null);
1475	>	if ((t.prev = tl) == null)
1476	>	hd = t;
1477	>	else
1478	>	tl.next = t;
1479	>	tl = t;
1480	>	}
1481	>	setTabAt(tab, j, new TreeBin<K,V>(hd));
1482	>	}
1483	>	}
1484	>	}
1485	>	if (insertAtFront) {
1486	>	++added;
1487	>	p.next = first;
1488	>	setTabAt(tab, j, p);
1489	>	}
1490	>	p = next;
1491	>	}
1492	>	table = tab;
1493	>	sizeCtl = n - (n >>> 2);
1494	>	baseCount = added;
1495	>	}
1496	>	}
1497	>
1498	>	// ConcurrentMap methods
1499	>
1500	>	/**
1501	>	* {@inheritDoc}
1502		*
1503	<	* @since 1.6
1503	>	* @return the previous value associated with the specified key,
1504	>	*         or {@code null} if there was no mapping for the key
1505	>	* @throws NullPointerException if the specified key or value is null
1506		*/
1507	<	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
1508	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
1507	>	public V putIfAbsent(K key, V value) {
1508	>	return putVal(key, value, true);
1509		}
1510
1511		/**
1512	<	* Creates a new, empty map with the specified initial capacity,
758	<	* and with default load factor (0.75) and concurrencyLevel (16).
1512	>	* {@inheritDoc}
1513		*
1514	<	* @param initialCapacity the initial capacity. The implementation
761	<	* performs internal sizing to accommodate this many elements.
762	<	* @throws IllegalArgumentException if the initial capacity of
763	<	* elements is negative.
1514	>	* @throws NullPointerException if the specified key is null
1515		*/
1516	<	public ConcurrentHashMap(int initialCapacity) {
1517	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1516	>	public boolean remove(Object key, Object value) {
1517	>	if (key == null)
1518	>	throw new NullPointerException();
1519	>	return value != null && replaceNode(key, null, value) != null;
1520		}
1521
1522		/**
1523	<	* Creates a new, empty map with a default initial capacity (16),
1524	<	* load factor (0.75) and concurrencyLevel (16).
1523	>	* {@inheritDoc}
1524	>	*
1525	>	* @throws NullPointerException if any of the arguments are null
1526		*/
1527	<	public ConcurrentHashMap() {
1528	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1527	>	public boolean replace(K key, V oldValue, V newValue) {
1528	>	if (key == null || oldValue == null || newValue == null)
1529	>	throw new NullPointerException();
1530	>	return replaceNode(key, newValue, oldValue) != null;
1531		}
1532
1533		/**
1534	<	* Creates a new map with the same mappings as the given map.
779	<	* 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).
1534	>	* {@inheritDoc}
1535		*
1536	<	* @param m the map
1536	>	* @return the previous value associated with the specified key,
1537	>	*         or {@code null} if there was no mapping for the key
1538	>	* @throws NullPointerException if the specified key or value is null
1539		*/
1540	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
1541	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
1542	<	DEFAULT_INITIAL_CAPACITY),
1543	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
789	<	putAll(m);
1540	>	public V replace(K key, V value) {
1541	>	if (key == null || value == null)
1542	>	throw new NullPointerException();
1543	>	return replaceNode(key, value, null);
1544		}
1545
1546	+	// Overrides of JDK8+ Map extension method defaults
1547	+
1548		/**
1549	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
1549	>	* Returns the value to which the specified key is mapped, or the
1550	>	* given default value if this map contains no mapping for the
1551	>	* key.
1552		*
1553	<	* @return <tt>true</tt> if this map contains no key-value mappings
1553	>	* @param key the key whose associated value is to be returned
1554	>	* @param defaultValue the value to return if this map contains
1555	>	* no mapping for the given key
1556	>	* @return the mapping for the key, if present; else the default value
1557	>	* @throws NullPointerException if the specified key is null
1558		*/
1559	<	public boolean isEmpty() {
1560	<	/*
1561	<	* Sum per-segment modCounts to avoid mis-reporting when
1562	<	* elements are concurrently added and removed in one segment
1563	<	* while checking another, in which case the table was never
1564	<	* actually empty at any point. (The sum ensures accuracy up
1565	<	* through at least 1<<31 per-segment modifications before
1566	<	* recheck.)  Methods size() and containsValue() use similar
1567	<	* constructions for stability checks.
1568	<	*/
1569	<	long sum = 0L;
1570	<	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;
1559	>	public V getOrDefault(Object key, V defaultValue) {
1560	>	V v;
1561	>	return (v = get(key)) == null ? defaultValue : v;
1562	>	}
1563	>
1564	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1565	>	if (action == null) throw new NullPointerException();
1566	>	Node<K,V>[] t;
1567	>	if ((t = table) != null) {
1568	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1569	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1570	>	action.accept(p.key, p.val);
1571		}
1572		}
1573	<	if (sum != 0L) { // recheck unless no modifications
1574	<	for (int j = 0; j < segments.length; ++j) {
1575	<	Segment<K,V> seg = segmentAt(segments, j);
1576	<	if (seg != null) {
1577	<	if (seg.count != 0)
1578	<	return false;
1579	<	sum -= seg.modCount;
1573	>	}
1574	>
1575	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1576	>	if (function == null) throw new NullPointerException();
1577	>	Node<K,V>[] t;
1578	>	if ((t = table) != null) {
1579	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1580	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1581	>	V oldValue = p.val;
1582	>	for (K key = p.key;;) {
1583	>	V newValue = function.apply(key, oldValue);
1584	>	if (newValue == null)
1585	>	throw new NullPointerException();
1586	>	if (replaceNode(key, newValue, oldValue) != null ||
1587	>	(oldValue = get(key)) == null)
1588	>	break;
1589		}
1590		}
826	–	if (sum != 0L)
827	–	return false;
1591		}
829	–	return true;
1592		}
1593
1594		/**
1595	<	* Returns the number of key-value mappings in this map.  If the
1596	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
1597	<	* <tt>Integer.MAX_VALUE</tt>.
1595	>	* If the specified key is not already associated with a value,
1596	>	* attempts to compute its value using the given mapping function
1597	>	* and enters it into this map unless {@code null}.  The entire
1598	>	* method invocation is performed atomically, so the function is
1599	>	* applied at most once per key.  Some attempted update operations
1600	>	* on this map by other threads may be blocked while computation
1601	>	* is in progress, so the computation should be short and simple,
1602	>	* and must not attempt to update any other mappings of this map.
1603		*
1604	<	* @return the number of key-value mappings in this map
1604	>	* @param key key with which the specified value is to be associated
1605	>	* @param mappingFunction the function to compute a value
1606	>	* @return the current (existing or computed) value associated with
1607	>	*         the specified key, or null if the computed value is null
1608	>	* @throws NullPointerException if the specified key or mappingFunction
1609	>	*         is null
1610	>	* @throws IllegalStateException if the computation detectably
1611	>	*         attempts a recursive update to this map that would
1612	>	*         otherwise never complete
1613	>	* @throws RuntimeException or Error if the mappingFunction does so,
1614	>	*         in which case the mapping is left unestablished
1615		*/
1616	<	public int size() {
1617	<	// Try a few times to get accurate count. On failure due to
1618	<	// continuous async changes in table, resort to locking.
1619	<	final Segment<K,V>[] segments = this.segments;
1620	<	final int segmentCount = segments.length;
1621	<
1622	<	long previousSum = 0L;
1623	<	for (int retries = -1; retries < RETRIES_BEFORE_LOCK; retries++) {
1624	<	long sum = 0L;    // sum of modCounts
1625	<	long size = 0L;
1626	<	for (int i = 0; i < segmentCount; i++) {
1627	<	Segment<K,V> segment = segmentAt(segments, i);
1628	<	if (segment != null) {
1629	<	sum += segment.modCount;
1630	<	size += segment.count;
1631	<	}
1632	<	}
1633	<	if (sum == previousSum)
1634	<	return ((size >>> 31) == 0) ? (int) size : Integer.MAX_VALUE;
1635	<	previousSum = sum;
1616	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1617	>	if (key == null || mappingFunction == null)
1618	>	throw new NullPointerException();
1619	>	int h = spread(key.hashCode());
1620	>	V val = null;
1621	>	int binCount = 0;
1622	>	for (Node<K,V>[] tab = table;;) {
1623	>	Node<K,V> f; int n, i, fh;
1624	>	if (tab == null || (n = tab.length) == 0)
1625	>	tab = initTable();
1626	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1627	>	Node<K,V> r = new ReservationNode<K,V>();
1628	>	synchronized (r) {
1629	>	if (casTabAt(tab, i, null, r)) {
1630	>	binCount = 1;
1631	>	Node<K,V> node = null;
1632	>	try {
1633	>	if ((val = mappingFunction.apply(key)) != null)
1634	>	node = new Node<K,V>(h, key, val, null);
1635	>	} finally {
1636	>	setTabAt(tab, i, node);
1637	>	}
1638	>	}
1639	>	}
1640	>	if (binCount != 0)
1641	>	break;
1642	>	}
1643	>	else if ((fh = f.hash) == MOVED)
1644	>	tab = helpTransfer(tab, f);
1645	>	else {
1646	>	boolean added = false;
1647	>	synchronized (f) {
1648	>	if (tabAt(tab, i) == f) {
1649	>	if (fh >= 0) {
1650	>	binCount = 1;
1651	>	for (Node<K,V> e = f;; ++binCount) {
1652	>	K ek;
1653	>	if (e.hash == h &&
1654	>	((ek = e.key) == key ||
1655	>	(ek != null && key.equals(ek)))) {
1656	>	val = e.val;
1657	>	break;
1658	>	}
1659	>	Node<K,V> pred = e;
1660	>	if ((e = e.next) == null) {
1661	>	if ((val = mappingFunction.apply(key)) != null) {
1662	>	if (pred.next != null)
1663	>	throw new IllegalStateException("Recursive update");
1664	>	added = true;
1665	>	pred.next = new Node<K,V>(h, key, val, null);
1666	>	}
1667	>	break;
1668	>	}
1669	>	}
1670	>	}
1671	>	else if (f instanceof TreeBin) {
1672	>	binCount = 2;
1673	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1674	>	TreeNode<K,V> r, p;
1675	>	if ((r = t.root) != null &&
1676	>	(p = r.findTreeNode(h, key, null)) != null)
1677	>	val = p.val;
1678	>	else if ((val = mappingFunction.apply(key)) != null) {
1679	>	added = true;
1680	>	t.putTreeVal(h, key, val);
1681	>	}
1682	>	}
1683	>	else if (f instanceof ReservationNode)
1684	>	throw new IllegalStateException("Recursive update");
1685	>	}
1686	>	}
1687	>	if (binCount != 0) {
1688	>	if (binCount >= TREEIFY_THRESHOLD)
1689	>	treeifyBin(tab, i);
1690	>	if (!added)
1691	>	return val;
1692	>	break;
1693	>	}
1694	>	}
1695		}
1696	<
1697	<	long size = 0L;
1698	<	for (int i = 0; i < segmentCount; i++) {
863	<	Segment<K,V> segment = ensureSegment(i);
864	<	segment.lock();
865	<	size += segment.count;
866	<	}
867	<	for (int i = 0; i < segmentCount; i++)
868	<	segments[i].unlock();
869	<	return ((size >>> 31) == 0) ? (int) size : Integer.MAX_VALUE;
1696	>	if (val != null)
1697	>	addCount(1L, binCount);
1698	>	return val;
1699		}
1700
1701		/**
1702	<	* Returns the value to which the specified key is mapped,
1703	<	* or {@code null} if this map contains no mapping for the key.
1704	<	*
1705	<	* <p>More formally, if this map contains a mapping from a key
1706	<	* {@code k} to a value {@code v} such that {@code key.equals(k)},
1707	<	* then this method returns {@code v}; otherwise it returns
1708	<	* {@code null}.  (There can be at most one such mapping.)
1702	>	* If the value for the specified key is present, attempts to
1703	>	* compute a new mapping given the key and its current mapped
1704	>	* value.  The entire method invocation is performed atomically.
1705	>	* Some attempted update operations on this map by other threads
1706	>	* may be blocked while computation is in progress, so the
1707	>	* computation should be short and simple, and must not attempt to
1708	>	* update any other mappings of this map.
1709		*
1710	<	* @throws NullPointerException if the specified key is null
1710	>	* @param key key with which a value may be associated
1711	>	* @param remappingFunction the function to compute a value
1712	>	* @return the new value associated with the specified key, or null if none
1713	>	* @throws NullPointerException if the specified key or remappingFunction
1714	>	*         is null
1715	>	* @throws IllegalStateException if the computation detectably
1716	>	*         attempts a recursive update to this map that would
1717	>	*         otherwise never complete
1718	>	* @throws RuntimeException or Error if the remappingFunction does so,
1719	>	*         in which case the mapping is unchanged
1720		*/
1721	<	public V get(Object key) {
1722	<	Segment<K,V> s; // manually integrate access methods to reduce overhead
1723	<	HashEntry<K,V>[] tab;
1724	<	int h = hash(key.hashCode());
1725	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
1726	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
1727	<	(tab = s.table) != null) {
1728	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
1729	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
1730	<	e != null; e = e.next) {
1731	<	K k;
1732	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
1733	<	return e.value;
1721	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1722	>	if (key == null || remappingFunction == null)
1723	>	throw new NullPointerException();
1724	>	int h = spread(key.hashCode());
1725	>	V val = null;
1726	>	int delta = 0;
1727	>	int binCount = 0;
1728	>	for (Node<K,V>[] tab = table;;) {
1729	>	Node<K,V> f; int n, i, fh;
1730	>	if (tab == null || (n = tab.length) == 0)
1731	>	tab = initTable();
1732	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1733	>	break;
1734	>	else if ((fh = f.hash) == MOVED)
1735	>	tab = helpTransfer(tab, f);
1736	>	else {
1737	>	synchronized (f) {
1738	>	if (tabAt(tab, i) == f) {
1739	>	if (fh >= 0) {
1740	>	binCount = 1;
1741	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1742	>	K ek;
1743	>	if (e.hash == h &&
1744	>	((ek = e.key) == key ||
1745	>	(ek != null && key.equals(ek)))) {
1746	>	val = remappingFunction.apply(key, e.val);
1747	>	if (val != null)
1748	>	e.val = val;
1749	>	else {
1750	>	delta = -1;
1751	>	Node<K,V> en = e.next;
1752	>	if (pred != null)
1753	>	pred.next = en;
1754	>	else
1755	>	setTabAt(tab, i, en);
1756	>	}
1757	>	break;
1758	>	}
1759	>	pred = e;
1760	>	if ((e = e.next) == null)
1761	>	break;
1762	>	}
1763	>	}
1764	>	else if (f instanceof TreeBin) {
1765	>	binCount = 2;
1766	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1767	>	TreeNode<K,V> r, p;
1768	>	if ((r = t.root) != null &&
1769	>	(p = r.findTreeNode(h, key, null)) != null) {
1770	>	val = remappingFunction.apply(key, p.val);
1771	>	if (val != null)
1772	>	p.val = val;
1773	>	else {
1774	>	delta = -1;
1775	>	if (t.removeTreeNode(p))
1776	>	setTabAt(tab, i, untreeify(t.first));
1777	>	}
1778	>	}
1779	>	}
1780	>	else if (f instanceof ReservationNode)
1781	>	throw new IllegalStateException("Recursive update");
1782	>	}
1783	>	}
1784	>	if (binCount != 0)
1785	>	break;
1786		}
1787		}
1788	<	return null;
1788	>	if (delta != 0)
1789	>	addCount((long)delta, binCount);
1790	>	return val;
1791		}
1792
1793		/**
1794	<	* Tests if the specified object is a key in this table.
1794	>	* Attempts to compute a mapping for the specified key and its
1795	>	* current mapped value (or {@code null} if there is no current
1796	>	* mapping). The entire method invocation is performed atomically.
1797	>	* Some attempted update operations on this map by other threads
1798	>	* may be blocked while computation is in progress, so the
1799	>	* computation should be short and simple, and must not attempt to
1800	>	* update any other mappings of this Map.
1801		*
1802	<	* @param  key   possible key
1803	<	* @return <tt>true</tt> if and only if the specified object
1804	<	*         is a key in this table, as determined by the
1805	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
1806	<	* @throws NullPointerException if the specified key is null
1807	<	*/
1808	<	@SuppressWarnings("unchecked")
1809	<	public boolean containsKey(Object key) {
1810	<	Segment<K,V> s; // same as get() except no need for volatile value read
1811	<	HashEntry<K,V>[] tab;
1812	<	int h = hash(key.hashCode());
1813	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
1814	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
1815	<	(tab = s.table) != null) {
1816	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
1817	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
1818	<	e != null; e = e.next) {
1819	<	K k;
1820	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
1821	<	return true;
1802	>	* @param key key with which the specified value is to be associated
1803	>	* @param remappingFunction the function to compute a value
1804	>	* @return the new value associated with the specified key, or null if none
1805	>	* @throws NullPointerException if the specified key or remappingFunction
1806	>	*         is null
1807	>	* @throws IllegalStateException if the computation detectably
1808	>	*         attempts a recursive update to this map that would
1809	>	*         otherwise never complete
1810	>	* @throws RuntimeException or Error if the remappingFunction does so,
1811	>	*         in which case the mapping is unchanged
1812	>	*/
1813	>	public V compute(K key,
1814	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1815	>	if (key == null || remappingFunction == null)
1816	>	throw new NullPointerException();
1817	>	int h = spread(key.hashCode());
1818	>	V val = null;
1819	>	int delta = 0;
1820	>	int binCount = 0;
1821	>	for (Node<K,V>[] tab = table;;) {
1822	>	Node<K,V> f; int n, i, fh;
1823	>	if (tab == null || (n = tab.length) == 0)
1824	>	tab = initTable();
1825	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1826	>	Node<K,V> r = new ReservationNode<K,V>();
1827	>	synchronized (r) {
1828	>	if (casTabAt(tab, i, null, r)) {
1829	>	binCount = 1;
1830	>	Node<K,V> node = null;
1831	>	try {
1832	>	if ((val = remappingFunction.apply(key, null)) != null) {
1833	>	delta = 1;
1834	>	node = new Node<K,V>(h, key, val, null);
1835	>	}
1836	>	} finally {
1837	>	setTabAt(tab, i, node);
1838	>	}
1839	>	}
1840	>	}
1841	>	if (binCount != 0)
1842	>	break;
1843	>	}
1844	>	else if ((fh = f.hash) == MOVED)
1845	>	tab = helpTransfer(tab, f);
1846	>	else {
1847	>	synchronized (f) {
1848	>	if (tabAt(tab, i) == f) {
1849	>	if (fh >= 0) {
1850	>	binCount = 1;
1851	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1852	>	K ek;
1853	>	if (e.hash == h &&
1854	>	((ek = e.key) == key ||
1855	>	(ek != null && key.equals(ek)))) {
1856	>	val = remappingFunction.apply(key, e.val);
1857	>	if (val != null)
1858	>	e.val = val;
1859	>	else {
1860	>	delta = -1;
1861	>	Node<K,V> en = e.next;
1862	>	if (pred != null)
1863	>	pred.next = en;
1864	>	else
1865	>	setTabAt(tab, i, en);
1866	>	}
1867	>	break;
1868	>	}
1869	>	pred = e;
1870	>	if ((e = e.next) == null) {
1871	>	val = remappingFunction.apply(key, null);
1872	>	if (val != null) {
1873	>	if (pred.next != null)
1874	>	throw new IllegalStateException("Recursive update");
1875	>	delta = 1;
1876	>	pred.next =
1877	>	new Node<K,V>(h, key, val, null);
1878	>	}
1879	>	break;
1880	>	}
1881	>	}
1882	>	}
1883	>	else if (f instanceof TreeBin) {
1884	>	binCount = 1;
1885	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1886	>	TreeNode<K,V> r, p;
1887	>	if ((r = t.root) != null)
1888	>	p = r.findTreeNode(h, key, null);
1889	>	else
1890	>	p = null;
1891	>	V pv = (p == null) ? null : p.val;
1892	>	val = remappingFunction.apply(key, pv);
1893	>	if (val != null) {
1894	>	if (p != null)
1895	>	p.val = val;
1896	>	else {
1897	>	delta = 1;
1898	>	t.putTreeVal(h, key, val);
1899	>	}
1900	>	}
1901	>	else if (p != null) {
1902	>	delta = -1;
1903	>	if (t.removeTreeNode(p))
1904	>	setTabAt(tab, i, untreeify(t.first));
1905	>	}
1906	>	}
1907	>	else if (f instanceof ReservationNode)
1908	>	throw new IllegalStateException("Recursive update");
1909	>	}
1910	>	}
1911	>	if (binCount != 0) {
1912	>	if (binCount >= TREEIFY_THRESHOLD)
1913	>	treeifyBin(tab, i);
1914	>	break;
1915	>	}
1916		}
1917		}
1918	<	return false;
1918	>	if (delta != 0)
1919	>	addCount((long)delta, binCount);
1920	>	return val;
1921		}
1922
1923		/**
1924	<	* Returns <tt>true</tt> if this map maps one or more keys to the
1925	<	* specified value. Note: This method requires a full internal
1926	<	* traversal of the hash table, and so is much slower than
1927	<	* method <tt>containsKey</tt>.
1924	>	* If the specified key is not already associated with a
1925	>	* (non-null) value, associates it with the given value.
1926	>	* Otherwise, replaces the value with the results of the given
1927	>	* remapping function, or removes if {@code null}. The entire
1928	>	* method invocation is performed atomically.  Some attempted
1929	>	* update operations on this map by other threads may be blocked
1930	>	* while computation is in progress, so the computation should be
1931	>	* short and simple, and must not attempt to update any other
1932	>	* mappings of this Map.
1933		*
1934	<	* @param value value whose presence in this map is to be tested
1935	<	* @return <tt>true</tt> if this map maps one or more keys to the
1936	<	*         specified value
1937	<	* @throws NullPointerException if the specified value is null
1934	>	* @param key key with which the specified value is to be associated
1935	>	* @param value the value to use if absent
1936	>	* @param remappingFunction the function to recompute a value if present
1937	>	* @return the new value associated with the specified key, or null if none
1938	>	* @throws NullPointerException if the specified key or the
1939	>	*         remappingFunction is null
1940	>	* @throws RuntimeException or Error if the remappingFunction does so,
1941	>	*         in which case the mapping is unchanged
1942		*/
1943	<	public boolean containsValue(Object value) {
1944	<	// Same idea as size()
942	<	if (value == null)
1943	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1944	>	if (key == null || value == null || remappingFunction == null)
1945		throw new NullPointerException();
1946	<	final Segment<K,V>[] segments = this.segments;
1947	<	long previousSum = 0L;
1948	<	int lockCount = 0;
1949	<	try {
1950	<	for (int retries = -1; ; retries++) {
1951	<	long sum = 0L;    // sum of modCounts
1952	<	for (int j = 0; j < segments.length; j++) {
1953	<	Segment<K,V> segment;
1954	<	if (retries == RETRIES_BEFORE_LOCK) {
1955	<	segment = ensureSegment(j);
1956	<	segment.lock();
1957	<	lockCount++;
1958	<	} else {
1959	<	segment = segmentAt(segments, j);
1960	<	if (segment == null)
1961	<	continue;
1962	<	}
1963	<	HashEntry<K,V>[] tab = segment.table;
1964	<	if (tab != null) {
1965	<	for (int i = 0 ; i < tab.length; i++) {
1966	<	HashEntry<K,V> e;
1967	<	for (e = entryAt(tab, i); e != null; e = e.next) {
1968	<	V v = e.value;
1969	<	if (v != null && value.equals(v))
1970	<	return true;
1946	>	int h = spread(key.hashCode());
1947	>	V val = null;
1948	>	int delta = 0;
1949	>	int binCount = 0;
1950	>	for (Node<K,V>[] tab = table;;) {
1951	>	Node<K,V> f; int n, i, fh;
1952	>	if (tab == null || (n = tab.length) == 0)
1953	>	tab = initTable();
1954	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1955	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) {
1956	>	delta = 1;
1957	>	val = value;
1958	>	break;
1959	>	}
1960	>	}
1961	>	else if ((fh = f.hash) == MOVED)
1962	>	tab = helpTransfer(tab, f);
1963	>	else {
1964	>	synchronized (f) {
1965	>	if (tabAt(tab, i) == f) {
1966	>	if (fh >= 0) {
1967	>	binCount = 1;
1968	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1969	>	K ek;
1970	>	if (e.hash == h &&
1971	>	((ek = e.key) == key ||
1972	>	(ek != null && key.equals(ek)))) {
1973	>	val = remappingFunction.apply(e.val, value);
1974	>	if (val != null)
1975	>	e.val = val;
1976	>	else {
1977	>	delta = -1;
1978	>	Node<K,V> en = e.next;
1979	>	if (pred != null)
1980	>	pred.next = en;
1981	>	else
1982	>	setTabAt(tab, i, en);
1983	>	}
1984	>	break;
1985	>	}
1986	>	pred = e;
1987	>	if ((e = e.next) == null) {
1988	>	delta = 1;
1989	>	val = value;
1990	>	pred.next =
1991	>	new Node<K,V>(h, key, val, null);
1992	>	break;
1993	>	}
1994	>	}
1995	>	}
1996	>	else if (f instanceof TreeBin) {
1997	>	binCount = 2;
1998	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1999	>	TreeNode<K,V> r = t.root;
2000	>	TreeNode<K,V> p = (r == null) ? null :
2001	>	r.findTreeNode(h, key, null);
2002	>	val = (p == null) ? value :
2003	>	remappingFunction.apply(p.val, value);
2004	>	if (val != null) {
2005	>	if (p != null)
2006	>	p.val = val;
2007	>	else {
2008	>	delta = 1;
2009	>	t.putTreeVal(h, key, val);
2010	>	}
2011	>	}
2012	>	else if (p != null) {
2013	>	delta = -1;
2014	>	if (t.removeTreeNode(p))
2015	>	setTabAt(tab, i, untreeify(t.first));
2016		}
2017		}
2018	<	sum += segment.modCount;
2018	>	else if (f instanceof ReservationNode)
2019	>	throw new IllegalStateException("Recursive update");
2020		}
2021		}
2022	<	if ((retries >= 0 && sum == previousSum) || lockCount > 0)
2023	<	return false;
2024	<	previousSum = sum;
2022	>	if (binCount != 0) {
2023	>	if (binCount >= TREEIFY_THRESHOLD)
2024	>	treeifyBin(tab, i);
2025	>	break;
2026	>	}
2027		}
978	–	} finally {
979	–	for (int j = 0; j < lockCount; j++)
980	–	segments[j].unlock();
2028		}
2029	+	if (delta != 0)
2030	+	addCount((long)delta, binCount);
2031	+	return val;
2032		}
2033
2034	+	// Hashtable legacy methods
2035	+
2036		/**
2037		* Legacy method testing if some key maps into the specified value
2038	<	* in this table.  This method is identical in functionality to
2039	<	* {@link #containsValue}, and exists solely to ensure
2038	>	* in this table.
2039	>	*
2040	>	* @deprecated This method is identical in functionality to
2041	>	* {@link #containsValue(Object)}, and exists solely to ensure
2042		* full compatibility with class {@link java.util.Hashtable},
2043		* which supported this method prior to introduction of the
2044		* Java Collections framework.
2045		*
2046		* @param  value a value to search for
2047	<	* @return <tt>true</tt> if and only if some key maps to the
2048	<	*         <tt>value</tt> argument in this table as
2049	<	*         determined by the <tt>equals</tt> method;
2050	<	*         <tt>false</tt> otherwise
2047	>	* @return {@code true} if and only if some key maps to the
2048	>	*         {@code value} argument in this table as
2049	>	*         determined by the {@code equals} method;
2050	>	*         {@code false} otherwise
2051		* @throws NullPointerException if the specified value is null
2052		*/
2053	+	@Deprecated
2054		public boolean contains(Object value) {
2055		return containsValue(value);
2056		}
2057
2058		/**
2059	<	* Maps the specified key to the specified value in this table.
1005	<	* Neither the key nor the value can be null.
1006	<	*
1007	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
1008	<	* with a key that is equal to the original key.
2059	>	* Returns an enumeration of the keys in this table.
2060		*
2061	<	* @param key key with which the specified value is to be associated
2062	<	* @param value value to be associated with the specified key
1012	<	* @return the previous value associated with <tt>key</tt>, or
1013	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
1014	<	* @throws NullPointerException if the specified key or value is null
2061	>	* @return an enumeration of the keys in this table
2062	>	* @see #keySet()
2063		*/
2064	<	@SuppressWarnings("unchecked")
2065	<	public V put(K key, V value) {
2066	<	Segment<K,V> s;
2067	<	if (value == null)
1020	<	throw new NullPointerException();
1021	<	int hash = hash(key.hashCode());
1022	<	int j = (hash >>> segmentShift) & segmentMask;
1023	<	if ((s = (Segment<K,V>)UNSAFE.getObject          // nonvolatile; recheck
1024	<	(segments, (j << SSHIFT) + SBASE)) == null) //  in ensureSegment
1025	<	s = ensureSegment(j);
1026	<	return s.put(key, hash, value, false);
2064	>	public Enumeration<K> keys() {
2065	>	Node<K,V>[] t;
2066	>	int f = (t = table) == null ? 0 : t.length;
2067	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2068		}
2069
2070		/**
2071	<	* {@inheritDoc}
2071	>	* Returns an enumeration of the values in this table.
2072		*
2073	<	* @return the previous value associated with the specified key,
2074	<	*         or <tt>null</tt> if there was no mapping for the key
1034	<	* @throws NullPointerException if the specified key or value is null
2073	>	* @return an enumeration of the values in this table
2074	>	* @see #values()
2075		*/
2076	<	@SuppressWarnings("unchecked")
2077	<	public V putIfAbsent(K key, V value) {
2078	<	Segment<K,V> s;
2079	<	if (value == null)
1040	<	throw new NullPointerException();
1041	<	int hash = hash(key.hashCode());
1042	<	int j = (hash >>> segmentShift) & segmentMask;
1043	<	if ((s = (Segment<K,V>)UNSAFE.getObject
1044	<	(segments, (j << SSHIFT) + SBASE)) == null)
1045	<	s = ensureSegment(j);
1046	<	return s.put(key, hash, value, true);
2076	>	public Enumeration<V> elements() {
2077	>	Node<K,V>[] t;
2078	>	int f = (t = table) == null ? 0 : t.length;
2079	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2080		}
2081
2082	+	// ConcurrentHashMap-only methods
2083	+
2084		/**
2085	<	* Copies all of the mappings from the specified map to this one.
2086	<	* These mappings replace any mappings that this map had for any of the
2087	<	* keys currently in the specified map.
2085	>	* Returns the number of mappings. This method should be used
2086	>	* instead of {@link #size} because a ConcurrentHashMap may
2087	>	* contain more mappings than can be represented as an int. The
2088	>	* value returned is an estimate; the actual count may differ if
2089	>	* there are concurrent insertions or removals.
2090		*
2091	<	* @param m mappings to be stored in this map
2091	>	* @return the number of mappings
2092	>	* @since 1.8
2093		*/
2094	<	public void putAll(Map<? extends K, ? extends V> m) {
2095	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
2096	<	put(e.getKey(), e.getValue());
2094	>	public long mappingCount() {
2095	>	long n = sumCount();
2096	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2097		}
2098
2099		/**
2100	<	* Removes the key (and its corresponding value) from this map.
2101	<	* This method does nothing if the key is not in the map.
2100	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2101	>	* from the given type to {@code Boolean.TRUE}.
2102		*
2103	<	* @param  key the key that needs to be removed
2104	<	* @return the previous value associated with <tt>key</tt>, or
2105	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
1068	<	* @throws NullPointerException if the specified key is null
2103	>	* @param <K> the element type of the returned set
2104	>	* @return the new set
2105	>	* @since 1.8
2106		*/
2107	<	public V remove(Object key) {
2108	<	int hash = hash(key.hashCode());
2109	<	Segment<K,V> s = segmentForHash(hash);
1073	<	return s == null ? null : s.remove(key, hash, null);
2107	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2108	>	return new KeySetView<K,Boolean>
2109	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2110		}
2111
2112		/**
2113	<	* {@inheritDoc}
2113	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2114	>	* from the given type to {@code Boolean.TRUE}.
2115		*
2116	<	* @throws NullPointerException if the specified key is null
2116	>	* @param initialCapacity The implementation performs internal
2117	>	* sizing to accommodate this many elements.
2118	>	* @param <K> the element type of the returned set
2119	>	* @return the new set
2120	>	* @throws IllegalArgumentException if the initial capacity of
2121	>	* elements is negative
2122	>	* @since 1.8
2123		*/
2124	<	public boolean remove(Object key, Object value) {
2125	<	int hash = hash(key.hashCode());
2126	<	Segment<K,V> s;
1084	<	return value != null && (s = segmentForHash(hash)) != null &&
1085	<	s.remove(key, hash, value) != null;
2124	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2125	>	return new KeySetView<K,Boolean>
2126	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2127		}
2128
2129		/**
2130	<	* {@inheritDoc}
2130	>	* Returns a {@link Set} view of the keys in this map, using the
2131	>	* given common mapped value for any additions (i.e., {@link
2132	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2133	>	* This is of course only appropriate if it is acceptable to use
2134	>	* the same value for all additions from this view.
2135		*
2136	<	* @throws NullPointerException if any of the arguments are null
2136	>	* @param mappedValue the mapped value to use for any additions
2137	>	* @return the set view
2138	>	* @throws NullPointerException if the mappedValue is null
2139		*/
2140	<	public boolean replace(K key, V oldValue, V newValue) {
2141	<	int hash = hash(key.hashCode());
1095	<	if (oldValue == null || newValue == null)
2140	>	public KeySetView<K,V> keySet(V mappedValue) {
2141	>	if (mappedValue == null)
2142		throw new NullPointerException();
2143	<	Segment<K,V> s = segmentForHash(hash);
1098	<	return s != null && s.replace(key, hash, oldValue, newValue);
2143	>	return new KeySetView<K,V>(this, mappedValue);
2144		}
2145
2146	+	/* ---------------- Special Nodes -------------- */
2147	+
2148		/**
2149	<	* {@inheritDoc}
1103	<	*
1104	<	* @return the previous value associated with the specified key,
1105	<	*         or <tt>null</tt> if there was no mapping for the key
1106	<	* @throws NullPointerException if the specified key or value is null
2149	>	* A node inserted at head of bins during transfer operations.
2150		*/
2151	<	public V replace(K key, V value) {
2152	<	int hash = hash(key.hashCode());
2153	<	if (value == null)
2154	<	throw new NullPointerException();
2155	<	Segment<K,V> s = segmentForHash(hash);
2156	<	return s == null ? null : s.replace(key, hash, value);
2151	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2152	>	final Node<K,V>[] nextTable;
2153	>	ForwardingNode(Node<K,V>[] tab) {
2154	>	super(MOVED, null, null, null);
2155	>	this.nextTable = tab;
2156	>	}
2157	>
2158	>	Node<K,V> find(int h, Object k) {
2159	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2160	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2161	>	Node<K,V> e; int n;
2162	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2163	>	(e = tabAt(tab, (n - 1) & h)) == null)
2164	>	return null;
2165	>	for (;;) {
2166	>	int eh; K ek;
2167	>	if ((eh = e.hash) == h &&
2168	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2169	>	return e;
2170	>	if (eh < 0) {
2171	>	if (e instanceof ForwardingNode) {
2172	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2173	>	continue outer;
2174	>	}
2175	>	else
2176	>	return e.find(h, k);
2177	>	}
2178	>	if ((e = e.next) == null)
2179	>	return null;
2180	>	}
2181	>	}
2182	>	}
2183		}
2184
2185		/**
2186	<	* Removes all of the mappings from this map.
2186	>	* A place-holder node used in computeIfAbsent and compute
2187		*/
2188	<	public void clear() {
2189	<	final Segment<K,V>[] segments = this.segments;
2190	<	for (int j = 0; j < segments.length; ++j) {
2191	<	Segment<K,V> s = segmentAt(segments, j);
2192	<	if (s != null)
2193	<	s.clear();
2188	>	static final class ReservationNode<K,V> extends Node<K,V> {
2189	>	ReservationNode() {
2190	>	super(RESERVED, null, null, null);
2191	>	}
2192	>
2193	>	Node<K,V> find(int h, Object k) {
2194	>	return null;
2195		}
2196		}
2197
2198	+	/* ---------------- Table Initialization and Resizing -------------- */
2199	+
2200		/**
2201	<	* Returns a {@link Set} view of the keys contained in this map.
2202	<	* The set is backed by the map, so changes to the map are
2203	<	* reflected in the set, and vice-versa.  The set supports element
2204	<	* removal, which removes the corresponding mapping from this map,
2205	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
1134	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
1135	<	* operations.  It does not support the <tt>add</tt> or
1136	<	* <tt>addAll</tt> operations.
1137	<	*
1138	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1139	<	* that will never throw {@link ConcurrentModificationException},
1140	<	* and guarantees to traverse elements as they existed upon
1141	<	* construction of the iterator, and may (but is not guaranteed to)
1142	<	* reflect any modifications subsequent to construction.
1143	<	*/
1144	<	public Set<K> keySet() {
1145	<	Set<K> ks = keySet;
1146	<	return (ks != null) ? ks : (keySet = new KeySet());
2201	>	* Returns the stamp bits for resizing a table of size n.
2202	>	* Must be negative when shifted left by RESIZE_STAMP_SHIFT.
2203	>	*/
2204	>	static final int resizeStamp(int n) {
2205	>	return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1));
2206		}
2207
2208		/**
2209	<	* Returns a {@link Collection} view of the values contained in this map.
1151	<	* The collection is backed by the map, so changes to the map are
1152	<	* reflected in the collection, and vice-versa.  The collection
1153	<	* supports element removal, which removes the corresponding
1154	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
1155	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
1156	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
1157	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
1158	<	*
1159	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1160	<	* that will never throw {@link ConcurrentModificationException},
1161	<	* and guarantees to traverse elements as they existed upon
1162	<	* construction of the iterator, and may (but is not guaranteed to)
1163	<	* reflect any modifications subsequent to construction.
2209	>	* Initializes table, using the size recorded in sizeCtl.
2210		*/
2211	<	public Collection<V> values() {
2212	<	Collection<V> vs = values;
2213	<	return (vs != null) ? vs : (values = new Values());
2211	>	private final Node<K,V>[] initTable() {
2212	>	Node<K,V>[] tab; int sc;
2213	>	while ((tab = table) == null || tab.length == 0) {
2214	>	if ((sc = sizeCtl) < 0)
2215	>	Thread.yield(); // lost initialization race; just spin
2216	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2217	>	try {
2218	>	if ((tab = table) == null || tab.length == 0) {
2219	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2220	>	@SuppressWarnings("unchecked")
2221	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2222	>	table = tab = nt;
2223	>	sc = n - (n >>> 2);
2224	>	}
2225	>	} finally {
2226	>	sizeCtl = sc;
2227	>	}
2228	>	break;
2229	>	}
2230	>	}
2231	>	return tab;
2232		}
2233
2234		/**
2235	<	* Returns a {@link Set} view of the mappings contained in this map.
2236	<	* The set is backed by the map, so changes to the map are
2237	<	* reflected in the set, and vice-versa.  The set supports element
2238	<	* removal, which removes the corresponding mapping from the map,
2239	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2240	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2241	<	* operations.  It does not support the <tt>add</tt> or
2242	<	* <tt>addAll</tt> operations.
1179	<	*
1180	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1181	<	* that will never throw {@link ConcurrentModificationException},
1182	<	* and guarantees to traverse elements as they existed upon
1183	<	* construction of the iterator, and may (but is not guaranteed to)
1184	<	* reflect any modifications subsequent to construction.
2235	>	* Adds to count, and if table is too small and not already
2236	>	* resizing, initiates transfer. If already resizing, helps
2237	>	* perform transfer if work is available.  Rechecks occupancy
2238	>	* after a transfer to see if another resize is already needed
2239	>	* because resizings are lagging additions.
2240	>	*
2241	>	* @param x the count to add
2242	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2243		*/
2244	<	public Set<Map.Entry<K,V>> entrySet() {
2245	<	Set<Map.Entry<K,V>> es = entrySet;
2246	<	return (es != null) ? es : (entrySet = new EntrySet());
2244	>	private final void addCount(long x, int check) {
2245	>	CounterCell[] as; long b, s;
2246	>	if ((as = counterCells) != null ||
2247	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2248	>	CounterCell a; long v; int m;
2249	>	boolean uncontended = true;
2250	>	if (as == null || (m = as.length - 1) < 0 ||
2251	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2252	>	!(uncontended =
2253	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2254	>	fullAddCount(x, uncontended);
2255	>	return;
2256	>	}
2257	>	if (check <= 1)
2258	>	return;
2259	>	s = sumCount();
2260	>	}
2261	>	if (check >= 0) {
2262	>	Node<K,V>[] tab, nt; int n, sc;
2263	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2264	>	(n = tab.length) < MAXIMUM_CAPACITY) {
2265	>	int rs = resizeStamp(n);
2266	>	if (sc < 0) {
2267	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2268	>	sc == rs + MAX_RESIZERS || (nt = nextTable) == null ||
2269	>	transferIndex <= 0)
2270	>	break;
2271	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1))
2272	>	transfer(tab, nt);
2273	>	}
2274	>	else if (U.compareAndSwapInt(this, SIZECTL, sc,
2275	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2276	>	transfer(tab, null);
2277	>	s = sumCount();
2278	>	}
2279	>	}
2280		}
2281
2282		/**
2283	<	* Returns an enumeration of the keys in this table.
1193	<	*
1194	<	* @return an enumeration of the keys in this table
1195	<	* @see #keySet()
2283	>	* Helps transfer if a resize is in progress.
2284		*/
2285	<	public Enumeration<K> keys() {
2286	<	return new KeyIterator();
2285	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2286	>	Node<K,V>[] nextTab; int sc;
2287	>	if (tab != null && (f instanceof ForwardingNode) &&
2288	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2289	>	int rs = resizeStamp(tab.length);
2290	>	while (nextTab == nextTable && table == tab &&
2291	>	(sc = sizeCtl) < 0) {
2292	>	if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 ||
2293	>	sc == rs + MAX_RESIZERS || transferIndex <= 0)
2294	>	break;
2295	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) {
2296	>	transfer(tab, nextTab);
2297	>	break;
2298	>	}
2299	>	}
2300	>	return nextTab;
2301	>	}
2302	>	return table;
2303		}
2304
2305		/**
2306	<	* Returns an enumeration of the values in this table.
2306	>	* Tries to presize table to accommodate the given number of elements.
2307		*
2308	<	* @return an enumeration of the values in this table
1205	<	* @see #values()
2308	>	* @param size number of elements (doesn't need to be perfectly accurate)
2309		*/
2310	<	public Enumeration<V> elements() {
2311	<	return new ValueIterator();
2310	>	private final void tryPresize(int size) {
2311	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2312	>	tableSizeFor(size + (size >>> 1) + 1);
2313	>	int sc;
2314	>	while ((sc = sizeCtl) >= 0) {
2315	>	Node<K,V>[] tab = table; int n;
2316	>	if (tab == null || (n = tab.length) == 0) {
2317	>	n = (sc > c) ? sc : c;
2318	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2319	>	try {
2320	>	if (table == tab) {
2321	>	@SuppressWarnings("unchecked")
2322	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2323	>	table = nt;
2324	>	sc = n - (n >>> 2);
2325	>	}
2326	>	} finally {
2327	>	sizeCtl = sc;
2328	>	}
2329	>	}
2330	>	}
2331	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2332	>	break;
2333	>	else if (tab == table) {
2334	>	int rs = resizeStamp(n);
2335	>	if (U.compareAndSwapInt(this, SIZECTL, sc,
2336	>	(rs << RESIZE_STAMP_SHIFT) + 2))
2337	>	transfer(tab, null);
2338	>	}
2339	>	}
2340		}
2341
2342	<	/* ---------------- Iterator Support -------------- */
2342	>	/**
2343	>	* Moves and/or copies the nodes in each bin to new table. See
2344	>	* above for explanation.
2345	>	*/
2346	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2347	>	int n = tab.length, stride;
2348	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2349	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2350	>	if (nextTab == null) {            // initiating
2351	>	try {
2352	>	@SuppressWarnings("unchecked")
2353	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2354	>	nextTab = nt;
2355	>	} catch (Throwable ex) {      // try to cope with OOME
2356	>	sizeCtl = Integer.MAX_VALUE;
2357	>	return;
2358	>	}
2359	>	nextTable = nextTab;
2360	>	transferIndex = n;
2361	>	}
2362	>	int nextn = nextTab.length;
2363	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2364	>	boolean advance = true;
2365	>	boolean finishing = false; // to ensure sweep before committing nextTab
2366	>	for (int i = 0, bound = 0;;) {
2367	>	Node<K,V> f; int fh;
2368	>	while (advance) {
2369	>	int nextIndex, nextBound;
2370	>	if (--i >= bound || finishing)
2371	>	advance = false;
2372	>	else if ((nextIndex = transferIndex) <= 0) {
2373	>	i = -1;
2374	>	advance = false;
2375	>	}
2376	>	else if (U.compareAndSwapInt
2377	>	(this, TRANSFERINDEX, nextIndex,
2378	>	nextBound = (nextIndex > stride ?
2379	>	nextIndex - stride : 0))) {
2380	>	bound = nextBound;
2381	>	i = nextIndex - 1;
2382	>	advance = false;
2383	>	}
2384	>	}
2385	>	if (i < 0 || i >= n || i + n >= nextn) {
2386	>	int sc;
2387	>	if (finishing) {
2388	>	nextTable = null;
2389	>	table = nextTab;
2390	>	sizeCtl = (n << 1) - (n >>> 1);
2391	>	return;
2392	>	}
2393	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) {
2394	>	if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT)
2395	>	return;
2396	>	finishing = advance = true;
2397	>	i = n; // recheck before commit
2398	>	}
2399	>	}
2400	>	else if ((f = tabAt(tab, i)) == null)
2401	>	advance = casTabAt(tab, i, null, fwd);
2402	>	else if ((fh = f.hash) == MOVED)
2403	>	advance = true; // already processed
2404	>	else {
2405	>	synchronized (f) {
2406	>	if (tabAt(tab, i) == f) {
2407	>	Node<K,V> ln, hn;
2408	>	if (fh >= 0) {
2409	>	int runBit = fh & n;
2410	>	Node<K,V> lastRun = f;
2411	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2412	>	int b = p.hash & n;
2413	>	if (b != runBit) {
2414	>	runBit = b;
2415	>	lastRun = p;
2416	>	}
2417	>	}
2418	>	if (runBit == 0) {
2419	>	ln = lastRun;
2420	>	hn = null;
2421	>	}
2422	>	else {
2423	>	hn = lastRun;
2424	>	ln = null;
2425	>	}
2426	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2427	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2428	>	if ((ph & n) == 0)
2429	>	ln = new Node<K,V>(ph, pk, pv, ln);
2430	>	else
2431	>	hn = new Node<K,V>(ph, pk, pv, hn);
2432	>	}
2433	>	setTabAt(nextTab, i, ln);
2434	>	setTabAt(nextTab, i + n, hn);
2435	>	setTabAt(tab, i, fwd);
2436	>	advance = true;
2437	>	}
2438	>	else if (f instanceof TreeBin) {
2439	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2440	>	TreeNode<K,V> lo = null, loTail = null;
2441	>	TreeNode<K,V> hi = null, hiTail = null;
2442	>	int lc = 0, hc = 0;
2443	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2444	>	int h = e.hash;
2445	>	TreeNode<K,V> p = new TreeNode<K,V>
2446	>	(h, e.key, e.val, null, null);
2447	>	if ((h & n) == 0) {
2448	>	if ((p.prev = loTail) == null)
2449	>	lo = p;
2450	>	else
2451	>	loTail.next = p;
2452	>	loTail = p;
2453	>	++lc;
2454	>	}
2455	>	else {
2456	>	if ((p.prev = hiTail) == null)
2457	>	hi = p;
2458	>	else
2459	>	hiTail.next = p;
2460	>	hiTail = p;
2461	>	++hc;
2462	>	}
2463	>	}
2464	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2465	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2466	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2467	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2468	>	setTabAt(nextTab, i, ln);
2469	>	setTabAt(nextTab, i + n, hn);
2470	>	setTabAt(tab, i, fwd);
2471	>	advance = true;
2472	>	}
2473	>	}
2474	>	}
2475	>	}
2476	>	}
2477	>	}
2478
2479	<	abstract class HashIterator {
1214	<	int nextSegmentIndex;
1215	<	int nextTableIndex;
1216	<	HashEntry<K,V>[] currentTable;
1217	<	HashEntry<K, V> nextEntry;
1218	<	HashEntry<K, V> lastReturned;
2479	>	/* ---------------- Counter support -------------- */
2480
2481	<	HashIterator() {
2482	<	nextSegmentIndex = segments.length - 1;
2483	<	nextTableIndex = -1;
2484	<	advance();
2481	>	/**
2482	>	* A padded cell for distributing counts.  Adapted from LongAdder
2483	>	* and Striped64.  See their internal docs for explanation.
2484	>	*/
2485	>	@sun.misc.Contended static final class CounterCell {
2486	>	volatile long value;
2487	>	CounterCell(long x) { value = x; }
2488	>	}
2489	>
2490	>	final long sumCount() {
2491	>	CounterCell[] as = counterCells; CounterCell a;
2492	>	long sum = baseCount;
2493	>	if (as != null) {
2494	>	for (int i = 0; i < as.length; ++i) {
2495	>	if ((a = as[i]) != null)
2496	>	sum += a.value;
2497	>	}
2498	>	}
2499	>	return sum;
2500	>	}
2501	>
2502	>	// See LongAdder version for explanation
2503	>	private final void fullAddCount(long x, boolean wasUncontended) {
2504	>	int h;
2505	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2506	>	ThreadLocalRandom.localInit();      // force initialization
2507	>	h = ThreadLocalRandom.getProbe();
2508	>	wasUncontended = true;
2509	>	}
2510	>	boolean collide = false;                // True if last slot nonempty
2511	>	for (;;) {
2512	>	CounterCell[] as; CounterCell a; int n; long v;
2513	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2514	>	if ((a = as[(n - 1) & h]) == null) {
2515	>	if (cellsBusy == 0) {            // Try to attach new Cell
2516	>	CounterCell r = new CounterCell(x); // Optimistic create
2517	>	if (cellsBusy == 0 &&
2518	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2519	>	boolean created = false;
2520	>	try {               // Recheck under lock
2521	>	CounterCell[] rs; int m, j;
2522	>	if ((rs = counterCells) != null &&
2523	>	(m = rs.length) > 0 &&
2524	>	rs[j = (m - 1) & h] == null) {
2525	>	rs[j] = r;
2526	>	created = true;
2527	>	}
2528	>	} finally {
2529	>	cellsBusy = 0;
2530	>	}
2531	>	if (created)
2532	>	break;
2533	>	continue;           // Slot is now non-empty
2534	>	}
2535	>	}
2536	>	collide = false;
2537	>	}
2538	>	else if (!wasUncontended)       // CAS already known to fail
2539	>	wasUncontended = true;      // Continue after rehash
2540	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2541	>	break;
2542	>	else if (counterCells != as || n >= NCPU)
2543	>	collide = false;            // At max size or stale
2544	>	else if (!collide)
2545	>	collide = true;
2546	>	else if (cellsBusy == 0 &&
2547	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2548	>	try {
2549	>	if (counterCells == as) {// Expand table unless stale
2550	>	CounterCell[] rs = new CounterCell[n << 1];
2551	>	for (int i = 0; i < n; ++i)
2552	>	rs[i] = as[i];
2553	>	counterCells = rs;
2554	>	}
2555	>	} finally {
2556	>	cellsBusy = 0;
2557	>	}
2558	>	collide = false;
2559	>	continue;                   // Retry with expanded table
2560	>	}
2561	>	h = ThreadLocalRandom.advanceProbe(h);
2562	>	}
2563	>	else if (cellsBusy == 0 && counterCells == as &&
2564	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2565	>	boolean init = false;
2566	>	try {                           // Initialize table
2567	>	if (counterCells == as) {
2568	>	CounterCell[] rs = new CounterCell[2];
2569	>	rs[h & 1] = new CounterCell(x);
2570	>	counterCells = rs;
2571	>	init = true;
2572	>	}
2573	>	} finally {
2574	>	cellsBusy = 0;
2575	>	}
2576	>	if (init)
2577	>	break;
2578	>	}
2579	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2580	>	break;                          // Fall back on using base
2581	>	}
2582	>	}
2583	>
2584	>	/* ---------------- Conversion from/to TreeBins -------------- */
2585	>
2586	>	/**
2587	>	* Replaces all linked nodes in bin at given index unless table is
2588	>	* too small, in which case resizes instead.
2589	>	*/
2590	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2591	>	Node<K,V> b; int n;
2592	>	if (tab != null) {
2593	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY)
2594	>	tryPresize(n << 1);
2595	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2596	>	synchronized (b) {
2597	>	if (tabAt(tab, index) == b) {
2598	>	TreeNode<K,V> hd = null, tl = null;
2599	>	for (Node<K,V> e = b; e != null; e = e.next) {
2600	>	TreeNode<K,V> p =
2601	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2602	>	null, null);
2603	>	if ((p.prev = tl) == null)
2604	>	hd = p;
2605	>	else
2606	>	tl.next = p;
2607	>	tl = p;
2608	>	}
2609	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2610	>	}
2611	>	}
2612	>	}
2613	>	}
2614	>	}
2615	>
2616	>	/**
2617	>	* Returns a list on non-TreeNodes replacing those in given list.
2618	>	*/
2619	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2620	>	Node<K,V> hd = null, tl = null;
2621	>	for (Node<K,V> q = b; q != null; q = q.next) {
2622	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null);
2623	>	if (tl == null)
2624	>	hd = p;
2625	>	else
2626	>	tl.next = p;
2627	>	tl = p;
2628	>	}
2629	>	return hd;
2630	>	}
2631	>
2632	>	/* ---------------- TreeNodes -------------- */
2633	>
2634	>	/**
2635	>	* Nodes for use in TreeBins
2636	>	*/
2637	>	static final class TreeNode<K,V> extends Node<K,V> {
2638	>	TreeNode<K,V> parent;  // red-black tree links
2639	>	TreeNode<K,V> left;
2640	>	TreeNode<K,V> right;
2641	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2642	>	boolean red;
2643	>
2644	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2645	>	TreeNode<K,V> parent) {
2646	>	super(hash, key, val, next);
2647	>	this.parent = parent;
2648	>	}
2649	>
2650	>	Node<K,V> find(int h, Object k) {
2651	>	return findTreeNode(h, k, null);
2652		}
2653
2654		/**
2655	<	* Sets nextEntry to first node of next non-empty table
2656	<	* (in backwards order, to simplify checks).
2655	>	* Returns the TreeNode (or null if not found) for the given key
2656	>	* starting at given root.
2657		*/
2658	<	final void advance() {
2659	<	for (;;) {
2660	<	if (nextTableIndex >= 0) {
2661	<	if ((nextEntry = entryAt(currentTable,
2662	<	nextTableIndex--)) != null)
2663	<	break;
2658	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2659	>	if (k != null) {
2660	>	TreeNode<K,V> p = this;
2661	>	do {
2662	>	int ph, dir; K pk; TreeNode<K,V> q;
2663	>	TreeNode<K,V> pl = p.left, pr = p.right;
2664	>	if ((ph = p.hash) > h)
2665	>	p = pl;
2666	>	else if (ph < h)
2667	>	p = pr;
2668	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2669	>	return p;
2670	>	else if (pl == null)
2671	>	p = pr;
2672	>	else if (pr == null)
2673	>	p = pl;
2674	>	else if ((kc != null ||
2675	>	(kc = comparableClassFor(k)) != null) &&
2676	>	(dir = compareComparables(kc, k, pk)) != 0)
2677	>	p = (dir < 0) ? pl : pr;
2678	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2679	>	return q;
2680	>	else
2681	>	p = pl;
2682	>	} while (p != null);
2683	>	}
2684	>	return null;
2685	>	}
2686	>	}
2687	>
2688	>	/* ---------------- TreeBins -------------- */
2689	>
2690	>	/**
2691	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2692	>	* keys or values, but instead point to list of TreeNodes and
2693	>	* their root. They also maintain a parasitic read-write lock
2694	>	* forcing writers (who hold bin lock) to wait for readers (who do
2695	>	* not) to complete before tree restructuring operations.
2696	>	*/
2697	>	static final class TreeBin<K,V> extends Node<K,V> {
2698	>	TreeNode<K,V> root;
2699	>	volatile TreeNode<K,V> first;
2700	>	volatile Thread waiter;
2701	>	volatile int lockState;
2702	>	// values for lockState
2703	>	static final int WRITER = 1; // set while holding write lock
2704	>	static final int WAITER = 2; // set when waiting for write lock
2705	>	static final int READER = 4; // increment value for setting read lock
2706	>
2707	>	/**
2708	>	* Tie-breaking utility for ordering insertions when equal
2709	>	* hashCodes and non-comparable. We don't require a total
2710	>	* order, just a consistent insertion rule to maintain
2711	>	* equivalence across rebalancings. Tie-breaking further than
2712	>	* necessary simplifies testing a bit.
2713	>	*/
2714	>	static int tieBreakOrder(Object a, Object b) {
2715	>	int d;
2716	>	if (a == null || b == null ||
2717	>	(d = a.getClass().getName().
2718	>	compareTo(b.getClass().getName())) == 0)
2719	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2720	>	-1 : 1);
2721	>	return d;
2722	>	}
2723	>
2724	>	/**
2725	>	* Creates bin with initial set of nodes headed by b.
2726	>	*/
2727	>	TreeBin(TreeNode<K,V> b) {
2728	>	super(TREEBIN, null, null, null);
2729	>	this.first = b;
2730	>	TreeNode<K,V> r = null;
2731	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2732	>	next = (TreeNode<K,V>)x.next;
2733	>	x.left = x.right = null;
2734	>	if (r == null) {
2735	>	x.parent = null;
2736	>	x.red = false;
2737	>	r = x;
2738		}
2739	<	else if (nextSegmentIndex >= 0) {
2740	<	Segment<K,V> seg = segmentAt(segments, nextSegmentIndex--);
2741	<	if (seg != null && (currentTable = seg.table) != null)
2742	<	nextTableIndex = currentTable.length - 1;
2739	>	else {
2740	>	K k = x.key;
2741	>	int h = x.hash;
2742	>	Class<?> kc = null;
2743	>	for (TreeNode<K,V> p = r;;) {
2744	>	int dir, ph;
2745	>	K pk = p.key;
2746	>	if ((ph = p.hash) > h)
2747	>	dir = -1;
2748	>	else if (ph < h)
2749	>	dir = 1;
2750	>	else if ((kc == null &&
2751	>	(kc = comparableClassFor(k)) == null) ||
2752	>	(dir = compareComparables(kc, k, pk)) == 0)
2753	>	dir = tieBreakOrder(k, pk);
2754	>	TreeNode<K,V> xp = p;
2755	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2756	>	x.parent = xp;
2757	>	if (dir <= 0)
2758	>	xp.left = x;
2759	>	else
2760	>	xp.right = x;
2761	>	r = balanceInsertion(r, x);
2762	>	break;
2763	>	}
2764	>	}
2765		}
2766	<	else
2766	>	}
2767	>	this.root = r;
2768	>	assert checkInvariants(root);
2769	>	}
2770	>
2771	>	/**
2772	>	* Acquires write lock for tree restructuring.
2773	>	*/
2774	>	private final void lockRoot() {
2775	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2776	>	contendedLock(); // offload to separate method
2777	>	}
2778	>
2779	>	/**
2780	>	* Releases write lock for tree restructuring.
2781	>	*/
2782	>	private final void unlockRoot() {
2783	>	lockState = 0;
2784	>	}
2785	>
2786	>	/**
2787	>	* Possibly blocks awaiting root lock.
2788	>	*/
2789	>	private final void contendedLock() {
2790	>	boolean waiting = false;
2791	>	for (int s;;) {
2792	>	if (((s = lockState) & ~WAITER) == 0) {
2793	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2794	>	if (waiting)
2795	>	waiter = null;
2796	>	return;
2797	>	}
2798	>	}
2799	>	else if ((s & WAITER) == 0) {
2800	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2801	>	waiting = true;
2802	>	waiter = Thread.currentThread();
2803	>	}
2804	>	}
2805	>	else if (waiting)
2806	>	LockSupport.park(this);
2807	>	}
2808	>	}
2809	>
2810	>	/**
2811	>	* Returns matching node or null if none. Tries to search
2812	>	* using tree comparisons from root, but continues linear
2813	>	* search when lock not available.
2814	>	*/
2815	>	final Node<K,V> find(int h, Object k) {
2816	>	if (k != null) {
2817	>	for (Node<K,V> e = first; e != null; ) {
2818	>	int s; K ek;
2819	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2820	>	if (e.hash == h &&
2821	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2822	>	return e;
2823	>	e = e.next;
2824	>	}
2825	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2826	>	s + READER)) {
2827	>	TreeNode<K,V> r, p;
2828	>	try {
2829	>	p = ((r = root) == null ? null :
2830	>	r.findTreeNode(h, k, null));
2831	>	} finally {
2832	>	Thread w;
2833	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2834	>	(READER|WAITER) && (w = waiter) != null)
2835	>	LockSupport.unpark(w);
2836	>	}
2837	>	return p;
2838	>	}
2839	>	}
2840	>	}
2841	>	return null;
2842	>	}
2843	>
2844	>	/**
2845	>	* Finds or adds a node.
2846	>	* @return null if added
2847	>	*/
2848	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2849	>	Class<?> kc = null;
2850	>	boolean searched = false;
2851	>	for (TreeNode<K,V> p = root;;) {
2852	>	int dir, ph; K pk;
2853	>	if (p == null) {
2854	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2855		break;
2856	+	}
2857	+	else if ((ph = p.hash) > h)
2858	+	dir = -1;
2859	+	else if (ph < h)
2860	+	dir = 1;
2861	+	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2862	+	return p;
2863	+	else if ((kc == null &&
2864	+	(kc = comparableClassFor(k)) == null) ||
2865	+	(dir = compareComparables(kc, k, pk)) == 0) {
2866	+	if (!searched) {
2867	+	TreeNode<K,V> q, ch;
2868	+	searched = true;
2869	+	if (((ch = p.left) != null &&
2870	+	(q = ch.findTreeNode(h, k, kc)) != null) ||
2871	+	((ch = p.right) != null &&
2872	+	(q = ch.findTreeNode(h, k, kc)) != null))
2873	+	return q;
2874	+	}
2875	+	dir = tieBreakOrder(k, pk);
2876	+	}
2877	+
2878	+	TreeNode<K,V> xp = p;
2879	+	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2880	+	TreeNode<K,V> x, f = first;
2881	+	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2882	+	if (f != null)
2883	+	f.prev = x;
2884	+	if (dir <= 0)
2885	+	xp.left = x;
2886	+	else
2887	+	xp.right = x;
2888	+	if (!xp.red)
2889	+	x.red = true;
2890	+	else {
2891	+	lockRoot();
2892	+	try {
2893	+	root = balanceInsertion(root, x);
2894	+	} finally {
2895	+	unlockRoot();
2896	+	}
2897	+	}
2898	+	break;
2899	+	}
2900		}
2901	+	assert checkInvariants(root);
2902	+	return null;
2903		}
2904
2905	<	final HashEntry<K,V> nextEntry() {
2906	<	HashEntry<K,V> e = nextEntry;
2907	<	if (e == null)
2908	<	throw new NoSuchElementException();
2909	<	lastReturned = e; // cannot assign until after null check
2910	<	if ((nextEntry = e.next) == null)
2911	<	advance();
2912	<	return e;
2905	>	/**
2906	>	* Removes the given node, that must be present before this
2907	>	* call.  This is messier than typical red-black deletion code
2908	>	* because we cannot swap the contents of an interior node
2909	>	* with a leaf successor that is pinned by "next" pointers
2910	>	* that are accessible independently of lock. So instead we
2911	>	* swap the tree linkages.
2912	>	*
2913	>	* @return true if now too small, so should be untreeified
2914	>	*/
2915	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2916	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2917	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2918	>	TreeNode<K,V> r, rl;
2919	>	if (pred == null)
2920	>	first = next;
2921	>	else
2922	>	pred.next = next;
2923	>	if (next != null)
2924	>	next.prev = pred;
2925	>	if (first == null) {
2926	>	root = null;
2927	>	return true;
2928	>	}
2929	>	if ((r = root) == null || r.right == null || // too small
2930	>	(rl = r.left) == null || rl.left == null)
2931	>	return true;
2932	>	lockRoot();
2933	>	try {
2934	>	TreeNode<K,V> replacement;
2935	>	TreeNode<K,V> pl = p.left;
2936	>	TreeNode<K,V> pr = p.right;
2937	>	if (pl != null && pr != null) {
2938	>	TreeNode<K,V> s = pr, sl;
2939	>	while ((sl = s.left) != null) // find successor
2940	>	s = sl;
2941	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2942	>	TreeNode<K,V> sr = s.right;
2943	>	TreeNode<K,V> pp = p.parent;
2944	>	if (s == pr) { // p was s's direct parent
2945	>	p.parent = s;
2946	>	s.right = p;
2947	>	}
2948	>	else {
2949	>	TreeNode<K,V> sp = s.parent;
2950	>	if ((p.parent = sp) != null) {
2951	>	if (s == sp.left)
2952	>	sp.left = p;
2953	>	else
2954	>	sp.right = p;
2955	>	}
2956	>	if ((s.right = pr) != null)
2957	>	pr.parent = s;
2958	>	}
2959	>	p.left = null;
2960	>	if ((p.right = sr) != null)
2961	>	sr.parent = p;
2962	>	if ((s.left = pl) != null)
2963	>	pl.parent = s;
2964	>	if ((s.parent = pp) == null)
2965	>	r = s;
2966	>	else if (p == pp.left)
2967	>	pp.left = s;
2968	>	else
2969	>	pp.right = s;
2970	>	if (sr != null)
2971	>	replacement = sr;
2972	>	else
2973	>	replacement = p;
2974	>	}
2975	>	else if (pl != null)
2976	>	replacement = pl;
2977	>	else if (pr != null)
2978	>	replacement = pr;
2979	>	else
2980	>	replacement = p;
2981	>	if (replacement != p) {
2982	>	TreeNode<K,V> pp = replacement.parent = p.parent;
2983	>	if (pp == null)
2984	>	r = replacement;
2985	>	else if (p == pp.left)
2986	>	pp.left = replacement;
2987	>	else
2988	>	pp.right = replacement;
2989	>	p.left = p.right = p.parent = null;
2990	>	}
2991	>
2992	>	root = (p.red) ? r : balanceDeletion(r, replacement);
2993	>
2994	>	if (p == replacement) {  // detach pointers
2995	>	TreeNode<K,V> pp;
2996	>	if ((pp = p.parent) != null) {
2997	>	if (p == pp.left)
2998	>	pp.left = null;
2999	>	else if (p == pp.right)
3000	>	pp.right = null;
3001	>	p.parent = null;
3002	>	}
3003	>	}
3004	>	} finally {
3005	>	unlockRoot();
3006	>	}
3007	>	assert checkInvariants(root);
3008	>	return false;
3009	>	}
3010	>
3011	>	/* ------------------------------------------------------------ */
3012	>	// Red-black tree methods, all adapted from CLR
3013	>
3014	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
3015	>	TreeNode<K,V> p) {
3016	>	TreeNode<K,V> r, pp, rl;
3017	>	if (p != null && (r = p.right) != null) {
3018	>	if ((rl = p.right = r.left) != null)
3019	>	rl.parent = p;
3020	>	if ((pp = r.parent = p.parent) == null)
3021	>	(root = r).red = false;
3022	>	else if (pp.left == p)
3023	>	pp.left = r;
3024	>	else
3025	>	pp.right = r;
3026	>	r.left = p;
3027	>	p.parent = r;
3028	>	}
3029	>	return root;
3030	>	}
3031	>
3032	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
3033	>	TreeNode<K,V> p) {
3034	>	TreeNode<K,V> l, pp, lr;
3035	>	if (p != null && (l = p.left) != null) {
3036	>	if ((lr = p.left = l.right) != null)
3037	>	lr.parent = p;
3038	>	if ((pp = l.parent = p.parent) == null)
3039	>	(root = l).red = false;
3040	>	else if (pp.right == p)
3041	>	pp.right = l;
3042	>	else
3043	>	pp.left = l;
3044	>	l.right = p;
3045	>	p.parent = l;
3046	>	}
3047	>	return root;
3048	>	}
3049	>
3050	>	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3051	>	TreeNode<K,V> x) {
3052	>	x.red = true;
3053	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3054	>	if ((xp = x.parent) == null) {
3055	>	x.red = false;
3056	>	return x;
3057	>	}
3058	>	else if (!xp.red || (xpp = xp.parent) == null)
3059	>	return root;
3060	>	if (xp == (xppl = xpp.left)) {
3061	>	if ((xppr = xpp.right) != null && xppr.red) {
3062	>	xppr.red = false;
3063	>	xp.red = false;
3064	>	xpp.red = true;
3065	>	x = xpp;
3066	>	}
3067	>	else {
3068	>	if (x == xp.right) {
3069	>	root = rotateLeft(root, x = xp);
3070	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3071	>	}
3072	>	if (xp != null) {
3073	>	xp.red = false;
3074	>	if (xpp != null) {
3075	>	xpp.red = true;
3076	>	root = rotateRight(root, xpp);
3077	>	}
3078	>	}
3079	>	}
3080	>	}
3081	>	else {
3082	>	if (xppl != null && xppl.red) {
3083	>	xppl.red = false;
3084	>	xp.red = false;
3085	>	xpp.red = true;
3086	>	x = xpp;
3087	>	}
3088	>	else {
3089	>	if (x == xp.left) {
3090	>	root = rotateRight(root, x = xp);
3091	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3092	>	}
3093	>	if (xp != null) {
3094	>	xp.red = false;
3095	>	if (xpp != null) {
3096	>	xpp.red = true;
3097	>	root = rotateLeft(root, xpp);
3098	>	}
3099	>	}
3100	>	}
3101	>	}
3102	>	}
3103	>	}
3104	>
3105	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3106	>	TreeNode<K,V> x) {
3107	>	for (TreeNode<K,V> xp, xpl, xpr;;) {
3108	>	if (x == null || x == root)
3109	>	return root;
3110	>	else if ((xp = x.parent) == null) {
3111	>	x.red = false;
3112	>	return x;
3113	>	}
3114	>	else if (x.red) {
3115	>	x.red = false;
3116	>	return root;
3117	>	}
3118	>	else if ((xpl = xp.left) == x) {
3119	>	if ((xpr = xp.right) != null && xpr.red) {
3120	>	xpr.red = false;
3121	>	xp.red = true;
3122	>	root = rotateLeft(root, xp);
3123	>	xpr = (xp = x.parent) == null ? null : xp.right;
3124	>	}
3125	>	if (xpr == null)
3126	>	x = xp;
3127	>	else {
3128	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3129	>	if ((sr == null || !sr.red) &&
3130	>	(sl == null || !sl.red)) {
3131	>	xpr.red = true;
3132	>	x = xp;
3133	>	}
3134	>	else {
3135	>	if (sr == null || !sr.red) {
3136	>	if (sl != null)
3137	>	sl.red = false;
3138	>	xpr.red = true;
3139	>	root = rotateRight(root, xpr);
3140	>	xpr = (xp = x.parent) == null ?
3141	>	null : xp.right;
3142	>	}
3143	>	if (xpr != null) {
3144	>	xpr.red = (xp == null) ? false : xp.red;
3145	>	if ((sr = xpr.right) != null)
3146	>	sr.red = false;
3147	>	}
3148	>	if (xp != null) {
3149	>	xp.red = false;
3150	>	root = rotateLeft(root, xp);
3151	>	}
3152	>	x = root;
3153	>	}
3154	>	}
3155	>	}
3156	>	else { // symmetric
3157	>	if (xpl != null && xpl.red) {
3158	>	xpl.red = false;
3159	>	xp.red = true;
3160	>	root = rotateRight(root, xp);
3161	>	xpl = (xp = x.parent) == null ? null : xp.left;
3162	>	}
3163	>	if (xpl == null)
3164	>	x = xp;
3165	>	else {
3166	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3167	>	if ((sl == null || !sl.red) &&
3168	>	(sr == null || !sr.red)) {
3169	>	xpl.red = true;
3170	>	x = xp;
3171	>	}
3172	>	else {
3173	>	if (sl == null || !sl.red) {
3174	>	if (sr != null)
3175	>	sr.red = false;
3176	>	xpl.red = true;
3177	>	root = rotateLeft(root, xpl);
3178	>	xpl = (xp = x.parent) == null ?
3179	>	null : xp.left;
3180	>	}
3181	>	if (xpl != null) {
3182	>	xpl.red = (xp == null) ? false : xp.red;
3183	>	if ((sl = xpl.left) != null)
3184	>	sl.red = false;
3185	>	}
3186	>	if (xp != null) {
3187	>	xp.red = false;
3188	>	root = rotateRight(root, xp);
3189	>	}
3190	>	x = root;
3191	>	}
3192	>	}
3193	>	}
3194	>	}
3195		}
3196
3197	<	public final boolean hasNext() { return nextEntry != null; }
3198	<	public final boolean hasMoreElements() { return nextEntry != null; }
3197	>	/**
3198	>	* Recursive invariant check
3199	>	*/
3200	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3201	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3202	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3203	>	if (tb != null && tb.next != t)
3204	>	return false;
3205	>	if (tn != null && tn.prev != t)
3206	>	return false;
3207	>	if (tp != null && t != tp.left && t != tp.right)
3208	>	return false;
3209	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3210	>	return false;
3211	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3212	>	return false;
3213	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3214	>	return false;
3215	>	if (tl != null && !checkInvariants(tl))
3216	>	return false;
3217	>	if (tr != null && !checkInvariants(tr))
3218	>	return false;
3219	>	return true;
3220	>	}
3221	>
3222	>	private static final sun.misc.Unsafe U = sun.misc.Unsafe.getUnsafe();
3223	>	private static final long LOCKSTATE;
3224	>	static {
3225	>	try {
3226	>	LOCKSTATE = U.objectFieldOffset
3227	>	(TreeBin.class.getDeclaredField("lockState"));
3228	>	} catch (ReflectiveOperationException e) {
3229	>	throw new Error(e);
3230	>	}
3231	>	}
3232	>	}
3233	>
3234	>	/* ----------------Table Traversal -------------- */
3235	>
3236	>	/**
3237	>	* Records the table, its length, and current traversal index for a
3238	>	* traverser that must process a region of a forwarded table before
3239	>	* proceeding with current table.
3240	>	*/
3241	>	static final class TableStack<K,V> {
3242	>	int length;
3243	>	int index;
3244	>	Node<K,V>[] tab;
3245	>	TableStack<K,V> next;
3246	>	}
3247	>
3248	>	/**
3249	>	* Encapsulates traversal for methods such as containsValue; also
3250	>	* serves as a base class for other iterators and spliterators.
3251	>	*
3252	>	* Method advance visits once each still-valid node that was
3253	>	* reachable upon iterator construction. It might miss some that
3254	>	* were added to a bin after the bin was visited, which is OK wrt
3255	>	* consistency guarantees. Maintaining this property in the face
3256	>	* of possible ongoing resizes requires a fair amount of
3257	>	* bookkeeping state that is difficult to optimize away amidst
3258	>	* volatile accesses.  Even so, traversal maintains reasonable
3259	>	* throughput.
3260	>	*
3261	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3262	>	* However, if the table has been resized, then all future steps
3263	>	* must traverse both the bin at the current index as well as at
3264	>	* (index + baseSize); and so on for further resizings. To
3265	>	* paranoically cope with potential sharing by users of iterators
3266	>	* across threads, iteration terminates if a bounds checks fails
3267	>	* for a table read.
3268	>	*/
3269	>	static class Traverser<K,V> {
3270	>	Node<K,V>[] tab;        // current table; updated if resized
3271	>	Node<K,V> next;         // the next entry to use
3272	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3273	>	int index;              // index of bin to use next
3274	>	int baseIndex;          // current index of initial table
3275	>	int baseLimit;          // index bound for initial table
3276	>	final int baseSize;     // initial table size
3277	>
3278	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3279	>	this.tab = tab;
3280	>	this.baseSize = size;
3281	>	this.baseIndex = this.index = index;
3282	>	this.baseLimit = limit;
3283	>	this.next = null;
3284	>	}
3285	>
3286	>	/**
3287	>	* Advances if possible, returning next valid node, or null if none.
3288	>	*/
3289	>	final Node<K,V> advance() {
3290	>	Node<K,V> e;
3291	>	if ((e = next) != null)
3292	>	e = e.next;
3293	>	for (;;) {
3294	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3295	>	if (e != null)
3296	>	return next = e;
3297	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3298	>	(n = t.length) <= (i = index) || i < 0)
3299	>	return next = null;
3300	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3301	>	if (e instanceof ForwardingNode) {
3302	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3303	>	e = null;
3304	>	pushState(t, i, n);
3305	>	continue;
3306	>	}
3307	>	else if (e instanceof TreeBin)
3308	>	e = ((TreeBin<K,V>)e).first;
3309	>	else
3310	>	e = null;
3311	>	}
3312	>	if (stack != null)
3313	>	recoverState(n);
3314	>	else if ((index = i + baseSize) >= n)
3315	>	index = ++baseIndex; // visit upper slots if present
3316	>	}
3317	>	}
3318	>
3319	>	/**
3320	>	* Saves traversal state upon encountering a forwarding node.
3321	>	*/
3322	>	private void pushState(Node<K,V>[] t, int i, int n) {
3323	>	TableStack<K,V> s = spare;  // reuse if possible
3324	>	if (s != null)
3325	>	spare = s.next;
3326	>	else
3327	>	s = new TableStack<K,V>();
3328	>	s.tab = t;
3329	>	s.length = n;
3330	>	s.index = i;
3331	>	s.next = stack;
3332	>	stack = s;
3333	>	}
3334	>
3335	>	/**
3336	>	* Possibly pops traversal state.
3337	>	*
3338	>	* @param n length of current table
3339	>	*/
3340	>	private void recoverState(int n) {
3341	>	TableStack<K,V> s; int len;
3342	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3343	>	n = len;
3344	>	index = s.index;
3345	>	tab = s.tab;
3346	>	s.tab = null;
3347	>	TableStack<K,V> next = s.next;
3348	>	s.next = spare; // save for reuse
3349	>	stack = next;
3350	>	spare = s;
3351	>	}
3352	>	if (s == null && (index += baseSize) >= n)
3353	>	index = ++baseIndex;
3354	>	}
3355	>	}
3356	>
3357	>	/**
3358	>	* Base of key, value, and entry Iterators. Adds fields to
3359	>	* Traverser to support iterator.remove.
3360	>	*/
3361	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3362	>	final ConcurrentHashMap<K,V> map;
3363	>	Node<K,V> lastReturned;
3364	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3365	>	ConcurrentHashMap<K,V> map) {
3366	>	super(tab, size, index, limit);
3367	>	this.map = map;
3368	>	advance();
3369	>	}
3370	>
3371	>	public final boolean hasNext() { return next != null; }
3372	>	public final boolean hasMoreElements() { return next != null; }
3373
3374		public final void remove() {
3375	<	if (lastReturned == null)
3375	>	Node<K,V> p;
3376	>	if ((p = lastReturned) == null)
3377		throw new IllegalStateException();
1263	–	ConcurrentHashMap.this.remove(lastReturned.key);
3378		lastReturned = null;
3379	+	map.replaceNode(p.key, null, null);
3380		}
3381		}
3382
3383	<	final class KeyIterator
3384	<	extends HashIterator
3385	<	implements Iterator<K>, Enumeration<K>
3386	<	{
3387	<	public final K next()        { return super.nextEntry().key; }
3388	<	public final K nextElement() { return super.nextEntry().key; }
3389	<	}
3390	<
3391	<	final class ValueIterator
3392	<	extends HashIterator
3393	<	implements Iterator<V>, Enumeration<V>
3394	<	{
3395	<	public final V next()        { return super.nextEntry().value; }
3396	<	public final V nextElement() { return super.nextEntry().value; }
3383	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3384	>	implements Iterator<K>, Enumeration<K> {
3385	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3386	>	ConcurrentHashMap<K,V> map) {
3387	>	super(tab, index, size, limit, map);
3388	>	}
3389	>
3390	>	public final K next() {
3391	>	Node<K,V> p;
3392	>	if ((p = next) == null)
3393	>	throw new NoSuchElementException();
3394	>	K k = p.key;
3395	>	lastReturned = p;
3396	>	advance();
3397	>	return k;
3398	>	}
3399	>
3400	>	public final K nextElement() { return next(); }
3401	>	}
3402	>
3403	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3404	>	implements Iterator<V>, Enumeration<V> {
3405	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3406	>	ConcurrentHashMap<K,V> map) {
3407	>	super(tab, index, size, limit, map);
3408	>	}
3409	>
3410	>	public final V next() {
3411	>	Node<K,V> p;
3412	>	if ((p = next) == null)
3413	>	throw new NoSuchElementException();
3414	>	V v = p.val;
3415	>	lastReturned = p;
3416	>	advance();
3417	>	return v;
3418	>	}
3419	>
3420	>	public final V nextElement() { return next(); }
3421	>	}
3422	>
3423	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3424	>	implements Iterator<Map.Entry<K,V>> {
3425	>	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3426	>	ConcurrentHashMap<K,V> map) {
3427	>	super(tab, index, size, limit, map);
3428	>	}
3429	>
3430	>	public final Map.Entry<K,V> next() {
3431	>	Node<K,V> p;
3432	>	if ((p = next) == null)
3433	>	throw new NoSuchElementException();
3434	>	K k = p.key;
3435	>	V v = p.val;
3436	>	lastReturned = p;
3437	>	advance();
3438	>	return new MapEntry<K,V>(k, v, map);
3439	>	}
3440		}
3441
3442		/**
3443	<	* Custom Entry class used by EntryIterator.next(), that relays
3444	<	* setValue changes to the underlying map.
3445	<	*/
3446	<	final class WriteThroughEntry
3447	<	extends AbstractMap.SimpleEntry<K,V>
3448	<	{
3449	<	WriteThroughEntry(K k, V v) {
3450	<	super(k,v);
3443	>	* Exported Entry for EntryIterator
3444	>	*/
3445	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3446	>	final K key; // non-null
3447	>	V val;       // non-null
3448	>	final ConcurrentHashMap<K,V> map;
3449	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3450	>	this.key = key;
3451	>	this.val = val;
3452	>	this.map = map;
3453	>	}
3454	>	public K getKey()        { return key; }
3455	>	public V getValue()      { return val; }
3456	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3457	>	public String toString() {
3458	>	return Helpers.mapEntryToString(key, val);
3459	>	}
3460	>
3461	>	public boolean equals(Object o) {
3462	>	Object k, v; Map.Entry<?,?> e;
3463	>	return ((o instanceof Map.Entry) &&
3464	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3465	>	(v = e.getValue()) != null &&
3466	>	(k == key || k.equals(key)) &&
3467	>	(v == val || v.equals(val)));
3468		}
3469
3470		/**
3471		* Sets our entry's value and writes through to the map. The
3472	<	* value to return is somewhat arbitrary here. Since a
3473	<	* WriteThroughEntry does not necessarily track asynchronous
3474	<	* changes, the most recent "previous" value could be
3475	<	* different from what we return (or could even have been
3476	<	* removed in which case the put will re-establish). We do not
1302	<	* and cannot guarantee more.
3472	>	* value to return is somewhat arbitrary here. Since we do not
3473	>	* necessarily track asynchronous changes, the most recent
3474	>	* "previous" value could be different from what we return (or
3475	>	* could even have been removed, in which case the put will
3476	>	* re-establish). We do not and cannot guarantee more.
3477		*/
3478		public V setValue(V value) {
3479		if (value == null) throw new NullPointerException();
3480	<	V v = super.setValue(value);
3481	<	ConcurrentHashMap.this.put(getKey(), value);
3480	>	V v = val;
3481	>	val = value;
3482	>	map.put(key, value);
3483		return v;
3484		}
3485		}
3486
3487	<	final class EntryIterator
3488	<	extends HashIterator
3489	<	implements Iterator<Entry<K,V>>
3490	<	{
3491	<	public Map.Entry<K,V> next() {
3492	<	HashEntry<K,V> e = super.nextEntry();
3493	<	return new WriteThroughEntry(e.key, e.value);
3487	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3488	>	implements Spliterator<K> {
3489	>	long est;               // size estimate
3490	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3491	>	long est) {
3492	>	super(tab, size, index, limit);
3493	>	this.est = est;
3494	>	}
3495	>
3496	>	public Spliterator<K> trySplit() {
3497	>	int i, f, h;
3498	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3499	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3500	>	f, est >>>= 1);
3501	>	}
3502	>
3503	>	public void forEachRemaining(Consumer<? super K> action) {
3504	>	if (action == null) throw new NullPointerException();
3505	>	for (Node<K,V> p; (p = advance()) != null;)
3506	>	action.accept(p.key);
3507	>	}
3508	>
3509	>	public boolean tryAdvance(Consumer<? super K> action) {
3510	>	if (action == null) throw new NullPointerException();
3511	>	Node<K,V> p;
3512	>	if ((p = advance()) == null)
3513	>	return false;
3514	>	action.accept(p.key);
3515	>	return true;
3516	>	}
3517	>
3518	>	public long estimateSize() { return est; }
3519	>
3520	>	public int characteristics() {
3521	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3522	>	Spliterator.NONNULL;
3523		}
3524		}
3525
3526	<	final class KeySet extends AbstractSet<K> {
3527	<	public Iterator<K> iterator() {
3528	<	return new KeyIterator();
3526	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3527	>	implements Spliterator<V> {
3528	>	long est;               // size estimate
3529	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3530	>	long est) {
3531	>	super(tab, size, index, limit);
3532	>	this.est = est;
3533		}
3534	<	public int size() {
3535	<	return ConcurrentHashMap.this.size();
3534	>
3535	>	public Spliterator<V> trySplit() {
3536	>	int i, f, h;
3537	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3538	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3539	>	f, est >>>= 1);
3540		}
3541	<	public boolean isEmpty() {
3542	<	return ConcurrentHashMap.this.isEmpty();
3541	>
3542	>	public void forEachRemaining(Consumer<? super V> action) {
3543	>	if (action == null) throw new NullPointerException();
3544	>	for (Node<K,V> p; (p = advance()) != null;)
3545	>	action.accept(p.val);
3546		}
3547	<	public boolean contains(Object o) {
3548	<	return ConcurrentHashMap.this.containsKey(o);
3547	>
3548	>	public boolean tryAdvance(Consumer<? super V> action) {
3549	>	if (action == null) throw new NullPointerException();
3550	>	Node<K,V> p;
3551	>	if ((p = advance()) == null)
3552	>	return false;
3553	>	action.accept(p.val);
3554	>	return true;
3555		}
3556	<	public boolean remove(Object o) {
3557	<	return ConcurrentHashMap.this.remove(o) != null;
3556	>
3557	>	public long estimateSize() { return est; }
3558	>
3559	>	public int characteristics() {
3560	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3561		}
3562	<	public void clear() {
3563	<	ConcurrentHashMap.this.clear();
3562	>	}
3563	>
3564	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3565	>	implements Spliterator<Map.Entry<K,V>> {
3566	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3567	>	long est;               // size estimate
3568	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3569	>	long est, ConcurrentHashMap<K,V> map) {
3570	>	super(tab, size, index, limit);
3571	>	this.map = map;
3572	>	this.est = est;
3573		}
3574	+
3575	+	public Spliterator<Map.Entry<K,V>> trySplit() {
3576	+	int i, f, h;
3577	+	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3578	+	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3579	+	f, est >>>= 1, map);
3580	+	}
3581	+
3582	+	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3583	+	if (action == null) throw new NullPointerException();
3584	+	for (Node<K,V> p; (p = advance()) != null; )
3585	+	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3586	+	}
3587	+
3588	+	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3589	+	if (action == null) throw new NullPointerException();
3590	+	Node<K,V> p;
3591	+	if ((p = advance()) == null)
3592	+	return false;
3593	+	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3594	+	return true;
3595	+	}
3596	+
3597	+	public long estimateSize() { return est; }
3598	+
3599	+	public int characteristics() {
3600	+	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3601	+	Spliterator.NONNULL;
3602	+	}
3603	+	}
3604	+
3605	+	// Parallel bulk operations
3606	+
3607	+	/**
3608	+	* Computes initial batch value for bulk tasks. The returned value
3609	+	* is approximately exp2 of the number of times (minus one) to
3610	+	* split task by two before executing leaf action. This value is
3611	+	* faster to compute and more convenient to use as a guide to
3612	+	* splitting than is the depth, since it is used while dividing by
3613	+	* two anyway.
3614	+	*/
3615	+	final int batchFor(long b) {
3616	+	long n;
3617	+	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3618	+	return 0;
3619	+	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3620	+	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3621	+	}
3622	+
3623	+	/**
3624	+	* Performs the given action for each (key, value).
3625	+	*
3626	+	* @param parallelismThreshold the (estimated) number of elements
3627	+	* needed for this operation to be executed in parallel
3628	+	* @param action the action
3629	+	* @since 1.8
3630	+	*/
3631	+	public void forEach(long parallelismThreshold,
3632	+	BiConsumer<? super K,? super V> action) {
3633	+	if (action == null) throw new NullPointerException();
3634	+	new ForEachMappingTask<K,V>
3635	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3636	+	action).invoke();
3637	+	}
3638	+
3639	+	/**
3640	+	* Performs the given action for each non-null transformation
3641	+	* of each (key, value).
3642	+	*
3643	+	* @param parallelismThreshold the (estimated) number of elements
3644	+	* needed for this operation to be executed in parallel
3645	+	* @param transformer a function returning the transformation
3646	+	* for an element, or null if there is no transformation (in
3647	+	* which case the action is not applied)
3648	+	* @param action the action
3649	+	* @param <U> the return type of the transformer
3650	+	* @since 1.8
3651	+	*/
3652	+	public <U> void forEach(long parallelismThreshold,
3653	+	BiFunction<? super K, ? super V, ? extends U> transformer,
3654	+	Consumer<? super U> action) {
3655	+	if (transformer == null || action == null)
3656	+	throw new NullPointerException();
3657	+	new ForEachTransformedMappingTask<K,V,U>
3658	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3659	+	transformer, action).invoke();
3660	+	}
3661	+
3662	+	/**
3663	+	* Returns a non-null result from applying the given search
3664	+	* function on each (key, value), or null if none.  Upon
3665	+	* success, further element processing is suppressed and the
3666	+	* results of any other parallel invocations of the search
3667	+	* function are ignored.
3668	+	*
3669	+	* @param parallelismThreshold the (estimated) number of elements
3670	+	* needed for this operation to be executed in parallel
3671	+	* @param searchFunction a function returning a non-null
3672	+	* result on success, else null
3673	+	* @param <U> the return type of the search function
3674	+	* @return a non-null result from applying the given search
3675	+	* function on each (key, value), or null if none
3676	+	* @since 1.8
3677	+	*/
3678	+	public <U> U search(long parallelismThreshold,
3679	+	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3680	+	if (searchFunction == null) throw new NullPointerException();
3681	+	return new SearchMappingsTask<K,V,U>
3682	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3683	+	searchFunction, new AtomicReference<U>()).invoke();
3684	+	}
3685	+
3686	+	/**
3687	+	* Returns the result of accumulating the given transformation
3688	+	* of all (key, value) pairs using the given reducer to
3689	+	* combine values, or null if none.
3690	+	*
3691	+	* @param parallelismThreshold the (estimated) number of elements
3692	+	* needed for this operation to be executed in parallel
3693	+	* @param transformer a function returning the transformation
3694	+	* for an element, or null if there is no transformation (in
3695	+	* which case it is not combined)
3696	+	* @param reducer a commutative associative combining function
3697	+	* @param <U> the return type of the transformer
3698	+	* @return the result of accumulating the given transformation
3699	+	* of all (key, value) pairs
3700	+	* @since 1.8
3701	+	*/
3702	+	public <U> U reduce(long parallelismThreshold,
3703	+	BiFunction<? super K, ? super V, ? extends U> transformer,
3704	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
3705	+	if (transformer == null || reducer == null)
3706	+	throw new NullPointerException();
3707	+	return new MapReduceMappingsTask<K,V,U>
3708	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3709	+	null, transformer, reducer).invoke();
3710	+	}
3711	+
3712	+	/**
3713	+	* Returns the result of accumulating the given transformation
3714	+	* of all (key, value) pairs using the given reducer to
3715	+	* combine values, and the given basis as an identity value.
3716	+	*
3717	+	* @param parallelismThreshold the (estimated) number of elements
3718	+	* needed for this operation to be executed in parallel
3719	+	* @param transformer a function returning the transformation
3720	+	* for an element
3721	+	* @param basis the identity (initial default value) for the reduction
3722	+	* @param reducer a commutative associative combining function
3723	+	* @return the result of accumulating the given transformation
3724	+	* of all (key, value) pairs
3725	+	* @since 1.8
3726	+	*/
3727	+	public double reduceToDouble(long parallelismThreshold,
3728	+	ToDoubleBiFunction<? super K, ? super V> transformer,
3729	+	double basis,
3730	+	DoubleBinaryOperator reducer) {
3731	+	if (transformer == null || reducer == null)
3732	+	throw new NullPointerException();
3733	+	return new MapReduceMappingsToDoubleTask<K,V>
3734	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3735	+	null, transformer, basis, reducer).invoke();
3736	+	}
3737	+
3738	+	/**
3739	+	* Returns the result of accumulating the given transformation
3740	+	* of all (key, value) pairs using the given reducer to
3741	+	* combine values, and the given basis as an identity value.
3742	+	*
3743	+	* @param parallelismThreshold the (estimated) number of elements
3744	+	* needed for this operation to be executed in parallel
3745	+	* @param transformer a function returning the transformation
3746	+	* for an element
3747	+	* @param basis the identity (initial default value) for the reduction
3748	+	* @param reducer a commutative associative combining function
3749	+	* @return the result of accumulating the given transformation
3750	+	* of all (key, value) pairs
3751	+	* @since 1.8
3752	+	*/
3753	+	public long reduceToLong(long parallelismThreshold,
3754	+	ToLongBiFunction<? super K, ? super V> transformer,
3755	+	long basis,
3756	+	LongBinaryOperator reducer) {
3757	+	if (transformer == null || reducer == null)
3758	+	throw new NullPointerException();
3759	+	return new MapReduceMappingsToLongTask<K,V>
3760	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3761	+	null, transformer, basis, reducer).invoke();
3762	+	}
3763	+
3764	+	/**
3765	+	* Returns the result of accumulating the given transformation
3766	+	* of all (key, value) pairs using the given reducer to
3767	+	* combine values, and the given basis as an identity value.
3768	+	*
3769	+	* @param parallelismThreshold the (estimated) number of elements
3770	+	* needed for this operation to be executed in parallel
3771	+	* @param transformer a function returning the transformation
3772	+	* for an element
3773	+	* @param basis the identity (initial default value) for the reduction
3774	+	* @param reducer a commutative associative combining function
3775	+	* @return the result of accumulating the given transformation
3776	+	* of all (key, value) pairs
3777	+	* @since 1.8
3778	+	*/
3779	+	public int reduceToInt(long parallelismThreshold,
3780	+	ToIntBiFunction<? super K, ? super V> transformer,
3781	+	int basis,
3782	+	IntBinaryOperator reducer) {
3783	+	if (transformer == null || reducer == null)
3784	+	throw new NullPointerException();
3785	+	return new MapReduceMappingsToIntTask<K,V>
3786	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3787	+	null, transformer, basis, reducer).invoke();
3788	+	}
3789	+
3790	+	/**
3791	+	* Performs the given action for each key.
3792	+	*
3793	+	* @param parallelismThreshold the (estimated) number of elements
3794	+	* needed for this operation to be executed in parallel
3795	+	* @param action the action
3796	+	* @since 1.8
3797	+	*/
3798	+	public void forEachKey(long parallelismThreshold,
3799	+	Consumer<? super K> action) {
3800	+	if (action == null) throw new NullPointerException();
3801	+	new ForEachKeyTask<K,V>
3802	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3803	+	action).invoke();
3804	+	}
3805	+
3806	+	/**
3807	+	* Performs the given action for each non-null transformation
3808	+	* of each key.
3809	+	*
3810	+	* @param parallelismThreshold the (estimated) number of elements
3811	+	* needed for this operation to be executed in parallel
3812	+	* @param transformer a function returning the transformation
3813	+	* for an element, or null if there is no transformation (in
3814	+	* which case the action is not applied)
3815	+	* @param action the action
3816	+	* @param <U> the return type of the transformer
3817	+	* @since 1.8
3818	+	*/
3819	+	public <U> void forEachKey(long parallelismThreshold,
3820	+	Function<? super K, ? extends U> transformer,
3821	+	Consumer<? super U> action) {
3822	+	if (transformer == null || action == null)
3823	+	throw new NullPointerException();
3824	+	new ForEachTransformedKeyTask<K,V,U>
3825	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3826	+	transformer, action).invoke();
3827	+	}
3828	+
3829	+	/**
3830	+	* Returns a non-null result from applying the given search
3831	+	* function on each key, or null if none. Upon success,
3832	+	* further element processing is suppressed and the results of
3833	+	* any other parallel invocations of the search function are
3834	+	* ignored.
3835	+	*
3836	+	* @param parallelismThreshold the (estimated) number of elements
3837	+	* needed for this operation to be executed in parallel
3838	+	* @param searchFunction a function returning a non-null
3839	+	* result on success, else null
3840	+	* @param <U> the return type of the search function
3841	+	* @return a non-null result from applying the given search
3842	+	* function on each key, or null if none
3843	+	* @since 1.8
3844	+	*/
3845	+	public <U> U searchKeys(long parallelismThreshold,
3846	+	Function<? super K, ? extends U> searchFunction) {
3847	+	if (searchFunction == null) throw new NullPointerException();
3848	+	return new SearchKeysTask<K,V,U>
3849	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3850	+	searchFunction, new AtomicReference<U>()).invoke();
3851	+	}
3852	+
3853	+	/**
3854	+	* Returns the result of accumulating all keys using the given
3855	+	* reducer to combine values, or null if none.
3856	+	*
3857	+	* @param parallelismThreshold the (estimated) number of elements
3858	+	* needed for this operation to be executed in parallel
3859	+	* @param reducer a commutative associative combining function
3860	+	* @return the result of accumulating all keys using the given
3861	+	* reducer to combine values, or null if none
3862	+	* @since 1.8
3863	+	*/
3864	+	public K reduceKeys(long parallelismThreshold,
3865	+	BiFunction<? super K, ? super K, ? extends K> reducer) {
3866	+	if (reducer == null) throw new NullPointerException();
3867	+	return new ReduceKeysTask<K,V>
3868	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3869	+	null, reducer).invoke();
3870	+	}
3871	+
3872	+	/**
3873	+	* Returns the result of accumulating the given transformation
3874	+	* of all keys using the given reducer to combine values, or
3875	+	* null if none.
3876	+	*
3877	+	* @param parallelismThreshold the (estimated) number of elements
3878	+	* needed for this operation to be executed in parallel
3879	+	* @param transformer a function returning the transformation
3880	+	* for an element, or null if there is no transformation (in
3881	+	* which case it is not combined)
3882	+	* @param reducer a commutative associative combining function
3883	+	* @param <U> the return type of the transformer
3884	+	* @return the result of accumulating the given transformation
3885	+	* of all keys
3886	+	* @since 1.8
3887	+	*/
3888	+	public <U> U reduceKeys(long parallelismThreshold,
3889	+	Function<? super K, ? extends U> transformer,
3890	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
3891	+	if (transformer == null || reducer == null)
3892	+	throw new NullPointerException();
3893	+	return new MapReduceKeysTask<K,V,U>
3894	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3895	+	null, transformer, reducer).invoke();
3896		}
3897
3898	<	final class Values extends AbstractCollection<V> {
3899	<	public Iterator<V> iterator() {
3900	<	return new ValueIterator();
3898	>	/**
3899	>	* Returns the result of accumulating the given transformation
3900	>	* of all keys using the given reducer to combine values, and
3901	>	* the given basis as an identity value.
3902	>	*
3903	>	* @param parallelismThreshold the (estimated) number of elements
3904	>	* needed for this operation to be executed in parallel
3905	>	* @param transformer a function returning the transformation
3906	>	* for an element
3907	>	* @param basis the identity (initial default value) for the reduction
3908	>	* @param reducer a commutative associative combining function
3909	>	* @return the result of accumulating the given transformation
3910	>	* of all keys
3911	>	* @since 1.8
3912	>	*/
3913	>	public double reduceKeysToDouble(long parallelismThreshold,
3914	>	ToDoubleFunction<? super K> transformer,
3915	>	double basis,
3916	>	DoubleBinaryOperator reducer) {
3917	>	if (transformer == null || reducer == null)
3918	>	throw new NullPointerException();
3919	>	return new MapReduceKeysToDoubleTask<K,V>
3920	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3921	>	null, transformer, basis, reducer).invoke();
3922	>	}
3923	>
3924	>	/**
3925	>	* Returns the result of accumulating the given transformation
3926	>	* of all keys using the given reducer to combine values, and
3927	>	* the given basis as an identity value.
3928	>	*
3929	>	* @param parallelismThreshold the (estimated) number of elements
3930	>	* needed for this operation to be executed in parallel
3931	>	* @param transformer a function returning the transformation
3932	>	* for an element
3933	>	* @param basis the identity (initial default value) for the reduction
3934	>	* @param reducer a commutative associative combining function
3935	>	* @return the result of accumulating the given transformation
3936	>	* of all keys
3937	>	* @since 1.8
3938	>	*/
3939	>	public long reduceKeysToLong(long parallelismThreshold,
3940	>	ToLongFunction<? super K> transformer,
3941	>	long basis,
3942	>	LongBinaryOperator reducer) {
3943	>	if (transformer == null || reducer == null)
3944	>	throw new NullPointerException();
3945	>	return new MapReduceKeysToLongTask<K,V>
3946	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3947	>	null, transformer, basis, reducer).invoke();
3948	>	}
3949	>
3950	>	/**
3951	>	* Returns the result of accumulating the given transformation
3952	>	* of all keys using the given reducer to combine values, and
3953	>	* the given basis as an identity value.
3954	>	*
3955	>	* @param parallelismThreshold the (estimated) number of elements
3956	>	* needed for this operation to be executed in parallel
3957	>	* @param transformer a function returning the transformation
3958	>	* for an element
3959	>	* @param basis the identity (initial default value) for the reduction
3960	>	* @param reducer a commutative associative combining function
3961	>	* @return the result of accumulating the given transformation
3962	>	* of all keys
3963	>	* @since 1.8
3964	>	*/
3965	>	public int reduceKeysToInt(long parallelismThreshold,
3966	>	ToIntFunction<? super K> transformer,
3967	>	int basis,
3968	>	IntBinaryOperator reducer) {
3969	>	if (transformer == null || reducer == null)
3970	>	throw new NullPointerException();
3971	>	return new MapReduceKeysToIntTask<K,V>
3972	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3973	>	null, transformer, basis, reducer).invoke();
3974	>	}
3975	>
3976	>	/**
3977	>	* Performs the given action for each value.
3978	>	*
3979	>	* @param parallelismThreshold the (estimated) number of elements
3980	>	* needed for this operation to be executed in parallel
3981	>	* @param action the action
3982	>	* @since 1.8
3983	>	*/
3984	>	public void forEachValue(long parallelismThreshold,
3985	>	Consumer<? super V> action) {
3986	>	if (action == null)
3987	>	throw new NullPointerException();
3988	>	new ForEachValueTask<K,V>
3989	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3990	>	action).invoke();
3991	>	}
3992	>
3993	>	/**
3994	>	* Performs the given action for each non-null transformation
3995	>	* of each value.
3996	>	*
3997	>	* @param parallelismThreshold the (estimated) number of elements
3998	>	* needed for this operation to be executed in parallel
3999	>	* @param transformer a function returning the transformation
4000	>	* for an element, or null if there is no transformation (in
4001	>	* which case the action is not applied)
4002	>	* @param action the action
4003	>	* @param <U> the return type of the transformer
4004	>	* @since 1.8
4005	>	*/
4006	>	public <U> void forEachValue(long parallelismThreshold,
4007	>	Function<? super V, ? extends U> transformer,
4008	>	Consumer<? super U> action) {
4009	>	if (transformer == null || action == null)
4010	>	throw new NullPointerException();
4011	>	new ForEachTransformedValueTask<K,V,U>
4012	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4013	>	transformer, action).invoke();
4014	>	}
4015	>
4016	>	/**
4017	>	* Returns a non-null result from applying the given search
4018	>	* function on each value, or null if none.  Upon success,
4019	>	* further element processing is suppressed and the results of
4020	>	* any other parallel invocations of the search function are
4021	>	* ignored.
4022	>	*
4023	>	* @param parallelismThreshold the (estimated) number of elements
4024	>	* needed for this operation to be executed in parallel
4025	>	* @param searchFunction a function returning a non-null
4026	>	* result on success, else null
4027	>	* @param <U> the return type of the search function
4028	>	* @return a non-null result from applying the given search
4029	>	* function on each value, or null if none
4030	>	* @since 1.8
4031	>	*/
4032	>	public <U> U searchValues(long parallelismThreshold,
4033	>	Function<? super V, ? extends U> searchFunction) {
4034	>	if (searchFunction == null) throw new NullPointerException();
4035	>	return new SearchValuesTask<K,V,U>
4036	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4037	>	searchFunction, new AtomicReference<U>()).invoke();
4038	>	}
4039	>
4040	>	/**
4041	>	* Returns the result of accumulating all values using the
4042	>	* given reducer to combine values, or null if none.
4043	>	*
4044	>	* @param parallelismThreshold the (estimated) number of elements
4045	>	* needed for this operation to be executed in parallel
4046	>	* @param reducer a commutative associative combining function
4047	>	* @return the result of accumulating all values
4048	>	* @since 1.8
4049	>	*/
4050	>	public V reduceValues(long parallelismThreshold,
4051	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4052	>	if (reducer == null) throw new NullPointerException();
4053	>	return new ReduceValuesTask<K,V>
4054	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4055	>	null, reducer).invoke();
4056	>	}
4057	>
4058	>	/**
4059	>	* Returns the result of accumulating the given transformation
4060	>	* of all values using the given reducer to combine values, or
4061	>	* null if none.
4062	>	*
4063	>	* @param parallelismThreshold the (estimated) number of elements
4064	>	* needed for this operation to be executed in parallel
4065	>	* @param transformer a function returning the transformation
4066	>	* for an element, or null if there is no transformation (in
4067	>	* which case it is not combined)
4068	>	* @param reducer a commutative associative combining function
4069	>	* @param <U> the return type of the transformer
4070	>	* @return the result of accumulating the given transformation
4071	>	* of all values
4072	>	* @since 1.8
4073	>	*/
4074	>	public <U> U reduceValues(long parallelismThreshold,
4075	>	Function<? super V, ? extends U> transformer,
4076	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4077	>	if (transformer == null || reducer == null)
4078	>	throw new NullPointerException();
4079	>	return new MapReduceValuesTask<K,V,U>
4080	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4081	>	null, transformer, reducer).invoke();
4082	>	}
4083	>
4084	>	/**
4085	>	* Returns the result of accumulating the given transformation
4086	>	* of all values using the given reducer to combine values,
4087	>	* and the given basis as an identity value.
4088	>	*
4089	>	* @param parallelismThreshold the (estimated) number of elements
4090	>	* needed for this operation to be executed in parallel
4091	>	* @param transformer a function returning the transformation
4092	>	* for an element
4093	>	* @param basis the identity (initial default value) for the reduction
4094	>	* @param reducer a commutative associative combining function
4095	>	* @return the result of accumulating the given transformation
4096	>	* of all values
4097	>	* @since 1.8
4098	>	*/
4099	>	public double reduceValuesToDouble(long parallelismThreshold,
4100	>	ToDoubleFunction<? super V> transformer,
4101	>	double basis,
4102	>	DoubleBinaryOperator reducer) {
4103	>	if (transformer == null || reducer == null)
4104	>	throw new NullPointerException();
4105	>	return new MapReduceValuesToDoubleTask<K,V>
4106	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4107	>	null, transformer, basis, reducer).invoke();
4108	>	}
4109	>
4110	>	/**
4111	>	* Returns the result of accumulating the given transformation
4112	>	* of all values using the given reducer to combine values,
4113	>	* and the given basis as an identity value.
4114	>	*
4115	>	* @param parallelismThreshold the (estimated) number of elements
4116	>	* needed for this operation to be executed in parallel
4117	>	* @param transformer a function returning the transformation
4118	>	* for an element
4119	>	* @param basis the identity (initial default value) for the reduction
4120	>	* @param reducer a commutative associative combining function
4121	>	* @return the result of accumulating the given transformation
4122	>	* of all values
4123	>	* @since 1.8
4124	>	*/
4125	>	public long reduceValuesToLong(long parallelismThreshold,
4126	>	ToLongFunction<? super V> transformer,
4127	>	long basis,
4128	>	LongBinaryOperator reducer) {
4129	>	if (transformer == null || reducer == null)
4130	>	throw new NullPointerException();
4131	>	return new MapReduceValuesToLongTask<K,V>
4132	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4133	>	null, transformer, basis, reducer).invoke();
4134	>	}
4135	>
4136	>	/**
4137	>	* Returns the result of accumulating the given transformation
4138	>	* of all values using the given reducer to combine values,
4139	>	* and the given basis as an identity value.
4140	>	*
4141	>	* @param parallelismThreshold the (estimated) number of elements
4142	>	* needed for this operation to be executed in parallel
4143	>	* @param transformer a function returning the transformation
4144	>	* for an element
4145	>	* @param basis the identity (initial default value) for the reduction
4146	>	* @param reducer a commutative associative combining function
4147	>	* @return the result of accumulating the given transformation
4148	>	* of all values
4149	>	* @since 1.8
4150	>	*/
4151	>	public int reduceValuesToInt(long parallelismThreshold,
4152	>	ToIntFunction<? super V> transformer,
4153	>	int basis,
4154	>	IntBinaryOperator reducer) {
4155	>	if (transformer == null || reducer == null)
4156	>	throw new NullPointerException();
4157	>	return new MapReduceValuesToIntTask<K,V>
4158	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4159	>	null, transformer, basis, reducer).invoke();
4160	>	}
4161	>
4162	>	/**
4163	>	* Performs the given action for each entry.
4164	>	*
4165	>	* @param parallelismThreshold the (estimated) number of elements
4166	>	* needed for this operation to be executed in parallel
4167	>	* @param action the action
4168	>	* @since 1.8
4169	>	*/
4170	>	public void forEachEntry(long parallelismThreshold,
4171	>	Consumer<? super Map.Entry<K,V>> action) {
4172	>	if (action == null) throw new NullPointerException();
4173	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4174	>	action).invoke();
4175	>	}
4176	>
4177	>	/**
4178	>	* Performs the given action for each non-null transformation
4179	>	* of each entry.
4180	>	*
4181	>	* @param parallelismThreshold the (estimated) number of elements
4182	>	* needed for this operation to be executed in parallel
4183	>	* @param transformer a function returning the transformation
4184	>	* for an element, or null if there is no transformation (in
4185	>	* which case the action is not applied)
4186	>	* @param action the action
4187	>	* @param <U> the return type of the transformer
4188	>	* @since 1.8
4189	>	*/
4190	>	public <U> void forEachEntry(long parallelismThreshold,
4191	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4192	>	Consumer<? super U> action) {
4193	>	if (transformer == null || action == null)
4194	>	throw new NullPointerException();
4195	>	new ForEachTransformedEntryTask<K,V,U>
4196	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4197	>	transformer, action).invoke();
4198	>	}
4199	>
4200	>	/**
4201	>	* Returns a non-null result from applying the given search
4202	>	* function on each entry, or null if none.  Upon success,
4203	>	* further element processing is suppressed and the results of
4204	>	* any other parallel invocations of the search function are
4205	>	* ignored.
4206	>	*
4207	>	* @param parallelismThreshold the (estimated) number of elements
4208	>	* needed for this operation to be executed in parallel
4209	>	* @param searchFunction a function returning a non-null
4210	>	* result on success, else null
4211	>	* @param <U> the return type of the search function
4212	>	* @return a non-null result from applying the given search
4213	>	* function on each entry, or null if none
4214	>	* @since 1.8
4215	>	*/
4216	>	public <U> U searchEntries(long parallelismThreshold,
4217	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4218	>	if (searchFunction == null) throw new NullPointerException();
4219	>	return new SearchEntriesTask<K,V,U>
4220	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4221	>	searchFunction, new AtomicReference<U>()).invoke();
4222	>	}
4223	>
4224	>	/**
4225	>	* Returns the result of accumulating all entries using the
4226	>	* given reducer to combine values, or null if none.
4227	>	*
4228	>	* @param parallelismThreshold the (estimated) number of elements
4229	>	* needed for this operation to be executed in parallel
4230	>	* @param reducer a commutative associative combining function
4231	>	* @return the result of accumulating all entries
4232	>	* @since 1.8
4233	>	*/
4234	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4235	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4236	>	if (reducer == null) throw new NullPointerException();
4237	>	return new ReduceEntriesTask<K,V>
4238	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4239	>	null, reducer).invoke();
4240	>	}
4241	>
4242	>	/**
4243	>	* Returns the result of accumulating the given transformation
4244	>	* of all entries using the given reducer to combine values,
4245	>	* or null if none.
4246	>	*
4247	>	* @param parallelismThreshold the (estimated) number of elements
4248	>	* needed for this operation to be executed in parallel
4249	>	* @param transformer a function returning the transformation
4250	>	* for an element, or null if there is no transformation (in
4251	>	* which case it is not combined)
4252	>	* @param reducer a commutative associative combining function
4253	>	* @param <U> the return type of the transformer
4254	>	* @return the result of accumulating the given transformation
4255	>	* of all entries
4256	>	* @since 1.8
4257	>	*/
4258	>	public <U> U reduceEntries(long parallelismThreshold,
4259	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4260	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4261	>	if (transformer == null || reducer == null)
4262	>	throw new NullPointerException();
4263	>	return new MapReduceEntriesTask<K,V,U>
4264	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4265	>	null, transformer, reducer).invoke();
4266	>	}
4267	>
4268	>	/**
4269	>	* Returns the result of accumulating the given transformation
4270	>	* of all entries using the given reducer to combine values,
4271	>	* and the given basis as an identity value.
4272	>	*
4273	>	* @param parallelismThreshold the (estimated) number of elements
4274	>	* needed for this operation to be executed in parallel
4275	>	* @param transformer a function returning the transformation
4276	>	* for an element
4277	>	* @param basis the identity (initial default value) for the reduction
4278	>	* @param reducer a commutative associative combining function
4279	>	* @return the result of accumulating the given transformation
4280	>	* of all entries
4281	>	* @since 1.8
4282	>	*/
4283	>	public double reduceEntriesToDouble(long parallelismThreshold,
4284	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4285	>	double basis,
4286	>	DoubleBinaryOperator reducer) {
4287	>	if (transformer == null || reducer == null)
4288	>	throw new NullPointerException();
4289	>	return new MapReduceEntriesToDoubleTask<K,V>
4290	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4291	>	null, transformer, basis, reducer).invoke();
4292	>	}
4293	>
4294	>	/**
4295	>	* Returns the result of accumulating the given transformation
4296	>	* of all entries using the given reducer to combine values,
4297	>	* and the given basis as an identity value.
4298	>	*
4299	>	* @param parallelismThreshold the (estimated) number of elements
4300	>	* needed for this operation to be executed in parallel
4301	>	* @param transformer a function returning the transformation
4302	>	* for an element
4303	>	* @param basis the identity (initial default value) for the reduction
4304	>	* @param reducer a commutative associative combining function
4305	>	* @return the result of accumulating the given transformation
4306	>	* of all entries
4307	>	* @since 1.8
4308	>	*/
4309	>	public long reduceEntriesToLong(long parallelismThreshold,
4310	>	ToLongFunction<Map.Entry<K,V>> transformer,
4311	>	long basis,
4312	>	LongBinaryOperator reducer) {
4313	>	if (transformer == null || reducer == null)
4314	>	throw new NullPointerException();
4315	>	return new MapReduceEntriesToLongTask<K,V>
4316	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4317	>	null, transformer, basis, reducer).invoke();
4318	>	}
4319	>
4320	>	/**
4321	>	* Returns the result of accumulating the given transformation
4322	>	* of all entries using the given reducer to combine values,
4323	>	* and the given basis as an identity value.
4324	>	*
4325	>	* @param parallelismThreshold the (estimated) number of elements
4326	>	* needed for this operation to be executed in parallel
4327	>	* @param transformer a function returning the transformation
4328	>	* for an element
4329	>	* @param basis the identity (initial default value) for the reduction
4330	>	* @param reducer a commutative associative combining function
4331	>	* @return the result of accumulating the given transformation
4332	>	* of all entries
4333	>	* @since 1.8
4334	>	*/
4335	>	public int reduceEntriesToInt(long parallelismThreshold,
4336	>	ToIntFunction<Map.Entry<K,V>> transformer,
4337	>	int basis,
4338	>	IntBinaryOperator reducer) {
4339	>	if (transformer == null || reducer == null)
4340	>	throw new NullPointerException();
4341	>	return new MapReduceEntriesToIntTask<K,V>
4342	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4343	>	null, transformer, basis, reducer).invoke();
4344	>	}
4345	>
4346	>
4347	>	/* ----------------Views -------------- */
4348	>
4349	>	/**
4350	>	* Base class for views.
4351	>	*/
4352	>	abstract static class CollectionView<K,V,E>
4353	>	implements Collection<E>, java.io.Serializable {
4354	>	private static final long serialVersionUID = 7249069246763182397L;
4355	>	final ConcurrentHashMap<K,V> map;
4356	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4357	>
4358	>	/**
4359	>	* Returns the map backing this view.
4360	>	*
4361	>	* @return the map backing this view
4362	>	*/
4363	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4364	>
4365	>	/**
4366	>	* Removes all of the elements from this view, by removing all
4367	>	* the mappings from the map backing this view.
4368	>	*/
4369	>	public final void clear()      { map.clear(); }
4370	>	public final int size()        { return map.size(); }
4371	>	public final boolean isEmpty() { return map.isEmpty(); }
4372	>
4373	>	// implementations below rely on concrete classes supplying these
4374	>	// abstract methods
4375	>	/**
4376	>	* Returns an iterator over the elements in this collection.
4377	>	*
4378	>	* <p>The returned iterator is
4379	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4380	>	*
4381	>	* @return an iterator over the elements in this collection
4382	>	*/
4383	>	public abstract Iterator<E> iterator();
4384	>	public abstract boolean contains(Object o);
4385	>	public abstract boolean remove(Object o);
4386	>
4387	>	private static final String oomeMsg = "Required array size too large";
4388	>
4389	>	public final Object[] toArray() {
4390	>	long sz = map.mappingCount();
4391	>	if (sz > MAX_ARRAY_SIZE)
4392	>	throw new OutOfMemoryError(oomeMsg);
4393	>	int n = (int)sz;
4394	>	Object[] r = new Object[n];
4395	>	int i = 0;
4396	>	for (E e : this) {
4397	>	if (i == n) {
4398	>	if (n >= MAX_ARRAY_SIZE)
4399	>	throw new OutOfMemoryError(oomeMsg);
4400	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4401	>	n = MAX_ARRAY_SIZE;
4402	>	else
4403	>	n += (n >>> 1) + 1;
4404	>	r = Arrays.copyOf(r, n);
4405	>	}
4406	>	r[i++] = e;
4407	>	}
4408	>	return (i == n) ? r : Arrays.copyOf(r, i);
4409		}
4410	<	public int size() {
4411	<	return ConcurrentHashMap.this.size();
4410	>
4411	>	@SuppressWarnings("unchecked")
4412	>	public final <T> T[] toArray(T[] a) {
4413	>	long sz = map.mappingCount();
4414	>	if (sz > MAX_ARRAY_SIZE)
4415	>	throw new OutOfMemoryError(oomeMsg);
4416	>	int m = (int)sz;
4417	>	T[] r = (a.length >= m) ? a :
4418	>	(T[])java.lang.reflect.Array
4419	>	.newInstance(a.getClass().getComponentType(), m);
4420	>	int n = r.length;
4421	>	int i = 0;
4422	>	for (E e : this) {
4423	>	if (i == n) {
4424	>	if (n >= MAX_ARRAY_SIZE)
4425	>	throw new OutOfMemoryError(oomeMsg);
4426	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4427	>	n = MAX_ARRAY_SIZE;
4428	>	else
4429	>	n += (n >>> 1) + 1;
4430	>	r = Arrays.copyOf(r, n);
4431	>	}
4432	>	r[i++] = (T)e;
4433	>	}
4434	>	if (a == r && i < n) {
4435	>	r[i] = null; // null-terminate
4436	>	return r;
4437	>	}
4438	>	return (i == n) ? r : Arrays.copyOf(r, i);
4439		}
4440	<	public boolean isEmpty() {
4441	<	return ConcurrentHashMap.this.isEmpty();
4440	>
4441	>	/**
4442	>	* Returns a string representation of this collection.
4443	>	* The string representation consists of the string representations
4444	>	* of the collection's elements in the order they are returned by
4445	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4446	>	* Adjacent elements are separated by the characters {@code ", "}
4447	>	* (comma and space).  Elements are converted to strings as by
4448	>	* {@link String#valueOf(Object)}.
4449	>	*
4450	>	* @return a string representation of this collection
4451	>	*/
4452	>	public final String toString() {
4453	>	StringBuilder sb = new StringBuilder();
4454	>	sb.append('[');
4455	>	Iterator<E> it = iterator();
4456	>	if (it.hasNext()) {
4457	>	for (;;) {
4458	>	Object e = it.next();
4459	>	sb.append(e == this ? "(this Collection)" : e);
4460	>	if (!it.hasNext())
4461	>	break;
4462	>	sb.append(',').append(' ');
4463	>	}
4464	>	}
4465	>	return sb.append(']').toString();
4466		}
4467	<	public boolean contains(Object o) {
4468	<	return ConcurrentHashMap.this.containsValue(o);
4467	>
4468	>	public final boolean containsAll(Collection<?> c) {
4469	>	if (c != this) {
4470	>	for (Object e : c) {
4471	>	if (e == null || !contains(e))
4472	>	return false;
4473	>	}
4474	>	}
4475	>	return true;
4476		}
4477	<	public void clear() {
4478	<	ConcurrentHashMap.this.clear();
4477	>
4478	>	public final boolean removeAll(Collection<?> c) {
4479	>	if (c == null) throw new NullPointerException();
4480	>	boolean modified = false;
4481	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4482	>	if (c.contains(it.next())) {
4483	>	it.remove();
4484	>	modified = true;
4485	>	}
4486	>	}
4487	>	return modified;
4488		}
4489	+
4490	+	public final boolean retainAll(Collection<?> c) {
4491	+	if (c == null) throw new NullPointerException();
4492	+	boolean modified = false;
4493	+	for (Iterator<E> it = iterator(); it.hasNext();) {
4494	+	if (!c.contains(it.next())) {
4495	+	it.remove();
4496	+	modified = true;
4497	+	}
4498	+	}
4499	+	return modified;
4500	+	}
4501	+
4502		}
4503
4504	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4505	<	public Iterator<Map.Entry<K,V>> iterator() {
4506	<	return new EntryIterator();
4504	>	/**
4505	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4506	>	* which additions may optionally be enabled by mapping to a
4507	>	* common value.  This class cannot be directly instantiated.
4508	>	* See {@link #keySet() keySet()},
4509	>	* {@link #keySet(Object) keySet(V)},
4510	>	* {@link #newKeySet() newKeySet()},
4511	>	* {@link #newKeySet(int) newKeySet(int)}.
4512	>	*
4513	>	* @since 1.8
4514	>	*/
4515	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4516	>	implements Set<K>, java.io.Serializable {
4517	>	private static final long serialVersionUID = 7249069246763182397L;
4518	>	private final V value;
4519	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4520	>	super(map);
4521	>	this.value = value;
4522	>	}
4523	>
4524	>	/**
4525	>	* Returns the default mapped value for additions,
4526	>	* or {@code null} if additions are not supported.
4527	>	*
4528	>	* @return the default mapped value for additions, or {@code null}
4529	>	* if not supported
4530	>	*/
4531	>	public V getMappedValue() { return value; }
4532	>
4533	>	/**
4534	>	* {@inheritDoc}
4535	>	* @throws NullPointerException if the specified key is null
4536	>	*/
4537	>	public boolean contains(Object o) { return map.containsKey(o); }
4538	>
4539	>	/**
4540	>	* Removes the key from this map view, by removing the key (and its
4541	>	* corresponding value) from the backing map.  This method does
4542	>	* nothing if the key is not in the map.
4543	>	*
4544	>	* @param  o the key to be removed from the backing map
4545	>	* @return {@code true} if the backing map contained the specified key
4546	>	* @throws NullPointerException if the specified key is null
4547	>	*/
4548	>	public boolean remove(Object o) { return map.remove(o) != null; }
4549	>
4550	>	/**
4551	>	* @return an iterator over the keys of the backing map
4552	>	*/
4553	>	public Iterator<K> iterator() {
4554	>	Node<K,V>[] t;
4555	>	ConcurrentHashMap<K,V> m = map;
4556	>	int f = (t = m.table) == null ? 0 : t.length;
4557	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4558	>	}
4559	>
4560	>	/**
4561	>	* Adds the specified key to this set view by mapping the key to
4562	>	* the default mapped value in the backing map, if defined.
4563	>	*
4564	>	* @param e key to be added
4565	>	* @return {@code true} if this set changed as a result of the call
4566	>	* @throws NullPointerException if the specified key is null
4567	>	* @throws UnsupportedOperationException if no default mapped value
4568	>	* for additions was provided
4569	>	*/
4570	>	public boolean add(K e) {
4571	>	V v;
4572	>	if ((v = value) == null)
4573	>	throw new UnsupportedOperationException();
4574	>	return map.putVal(e, v, true) == null;
4575		}
4576	+
4577	+	/**
4578	+	* Adds all of the elements in the specified collection to this set,
4579	+	* as if by calling {@link #add} on each one.
4580	+	*
4581	+	* @param c the elements to be inserted into this set
4582	+	* @return {@code true} if this set changed as a result of the call
4583	+	* @throws NullPointerException if the collection or any of its
4584	+	* elements are {@code null}
4585	+	* @throws UnsupportedOperationException if no default mapped value
4586	+	* for additions was provided
4587	+	*/
4588	+	public boolean addAll(Collection<? extends K> c) {
4589	+	boolean added = false;
4590	+	V v;
4591	+	if ((v = value) == null)
4592	+	throw new UnsupportedOperationException();
4593	+	for (K e : c) {
4594	+	if (map.putVal(e, v, true) == null)
4595	+	added = true;
4596	+	}
4597	+	return added;
4598	+	}
4599	+
4600	+	public int hashCode() {
4601	+	int h = 0;
4602	+	for (K e : this)
4603	+	h += e.hashCode();
4604	+	return h;
4605	+	}
4606	+
4607	+	public boolean equals(Object o) {
4608	+	Set<?> c;
4609	+	return ((o instanceof Set) &&
4610	+	((c = (Set<?>)o) == this ||
4611	+	(containsAll(c) && c.containsAll(this))));
4612	+	}
4613	+
4614	+	public Spliterator<K> spliterator() {
4615	+	Node<K,V>[] t;
4616	+	ConcurrentHashMap<K,V> m = map;
4617	+	long n = m.sumCount();
4618	+	int f = (t = m.table) == null ? 0 : t.length;
4619	+	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4620	+	}
4621	+
4622	+	public void forEach(Consumer<? super K> action) {
4623	+	if (action == null) throw new NullPointerException();
4624	+	Node<K,V>[] t;
4625	+	if ((t = map.table) != null) {
4626	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4627	+	for (Node<K,V> p; (p = it.advance()) != null; )
4628	+	action.accept(p.key);
4629	+	}
4630	+	}
4631	+	}
4632	+
4633	+	/**
4634	+	* A view of a ConcurrentHashMap as a {@link Collection} of
4635	+	* values, in which additions are disabled. This class cannot be
4636	+	* directly instantiated. See {@link #values()}.
4637	+	*/
4638	+	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4639	+	implements Collection<V>, java.io.Serializable {
4640	+	private static final long serialVersionUID = 2249069246763182397L;
4641	+	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4642	+	public final boolean contains(Object o) {
4643	+	return map.containsValue(o);
4644	+	}
4645	+
4646	+	public final boolean remove(Object o) {
4647	+	if (o != null) {
4648	+	for (Iterator<V> it = iterator(); it.hasNext();) {
4649	+	if (o.equals(it.next())) {
4650	+	it.remove();
4651	+	return true;
4652	+	}
4653	+	}
4654	+	}
4655	+	return false;
4656	+	}
4657	+
4658	+	public final Iterator<V> iterator() {
4659	+	ConcurrentHashMap<K,V> m = map;
4660	+	Node<K,V>[] t;
4661	+	int f = (t = m.table) == null ? 0 : t.length;
4662	+	return new ValueIterator<K,V>(t, f, 0, f, m);
4663	+	}
4664	+
4665	+	public final boolean add(V e) {
4666	+	throw new UnsupportedOperationException();
4667	+	}
4668	+	public final boolean addAll(Collection<? extends V> c) {
4669	+	throw new UnsupportedOperationException();
4670	+	}
4671	+
4672	+	public Spliterator<V> spliterator() {
4673	+	Node<K,V>[] t;
4674	+	ConcurrentHashMap<K,V> m = map;
4675	+	long n = m.sumCount();
4676	+	int f = (t = m.table) == null ? 0 : t.length;
4677	+	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4678	+	}
4679	+
4680	+	public void forEach(Consumer<? super V> action) {
4681	+	if (action == null) throw new NullPointerException();
4682	+	Node<K,V>[] t;
4683	+	if ((t = map.table) != null) {
4684	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4685	+	for (Node<K,V> p; (p = it.advance()) != null; )
4686	+	action.accept(p.val);
4687	+	}
4688	+	}
4689	+	}
4690	+
4691	+	/**
4692	+	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4693	+	* entries.  This class cannot be directly instantiated. See
4694	+	* {@link #entrySet()}.
4695	+	*/
4696	+	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4697	+	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4698	+	private static final long serialVersionUID = 2249069246763182397L;
4699	+	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4700	+
4701		public boolean contains(Object o) {
4702	<	if (!(o instanceof Map.Entry))
4703	<	return false;
4704	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4705	<	V v = ConcurrentHashMap.this.get(e.getKey());
4706	<	return v != null && v.equals(e.getValue());
4702	>	Object k, v, r; Map.Entry<?,?> e;
4703	>	return ((o instanceof Map.Entry) &&
4704	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4705	>	(r = map.get(k)) != null &&
4706	>	(v = e.getValue()) != null &&
4707	>	(v == r || v.equals(r)));
4708		}
4709	+
4710		public boolean remove(Object o) {
4711	<	if (!(o instanceof Map.Entry))
4712	<	return false;
4713	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4714	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
4711	>	Object k, v; Map.Entry<?,?> e;
4712	>	return ((o instanceof Map.Entry) &&
4713	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4714	>	(v = e.getValue()) != null &&
4715	>	map.remove(k, v));
4716	>	}
4717	>
4718	>	/**
4719	>	* @return an iterator over the entries of the backing map
4720	>	*/
4721	>	public Iterator<Map.Entry<K,V>> iterator() {
4722	>	ConcurrentHashMap<K,V> m = map;
4723	>	Node<K,V>[] t;
4724	>	int f = (t = m.table) == null ? 0 : t.length;
4725	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4726	>	}
4727	>
4728	>	public boolean add(Entry<K,V> e) {
4729	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4730		}
4731	<	public int size() {
4732	<	return ConcurrentHashMap.this.size();
4731	>
4732	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4733	>	boolean added = false;
4734	>	for (Entry<K,V> e : c) {
4735	>	if (add(e))
4736	>	added = true;
4737	>	}
4738	>	return added;
4739		}
4740	<	public boolean isEmpty() {
4741	<	return ConcurrentHashMap.this.isEmpty();
4740	>
4741	>	public final int hashCode() {
4742	>	int h = 0;
4743	>	Node<K,V>[] t;
4744	>	if ((t = map.table) != null) {
4745	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4746	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4747	>	h += p.hashCode();
4748	>	}
4749	>	}
4750	>	return h;
4751		}
4752	<	public void clear() {
4753	<	ConcurrentHashMap.this.clear();
4752	>
4753	>	public final boolean equals(Object o) {
4754	>	Set<?> c;
4755	>	return ((o instanceof Set) &&
4756	>	((c = (Set<?>)o) == this ||
4757	>	(containsAll(c) && c.containsAll(this))));
4758	>	}
4759	>
4760	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4761	>	Node<K,V>[] t;
4762	>	ConcurrentHashMap<K,V> m = map;
4763	>	long n = m.sumCount();
4764	>	int f = (t = m.table) == null ? 0 : t.length;
4765	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4766	>	}
4767	>
4768	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4769	>	if (action == null) throw new NullPointerException();
4770	>	Node<K,V>[] t;
4771	>	if ((t = map.table) != null) {
4772	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4773	>	for (Node<K,V> p; (p = it.advance()) != null; )
4774	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4775	>	}
4776		}
4777	+
4778		}
4779
4780	<	/* ---------------- Serialization Support -------------- */
4780	>	// -------------------------------------------------------
4781
4782		/**
4783	<	* Saves the state of the <tt>ConcurrentHashMap</tt> instance to a
4784	<	* stream (i.e., serializes it).
1394	<	* @param s the stream
1395	<	* @serialData
1396	<	* the key (Object) and value (Object)
1397	<	* for each key-value mapping, followed by a null pair.
1398	<	* The key-value mappings are emitted in no particular order.
4783	>	* Base class for bulk tasks. Repeats some fields and code from
4784	>	* class Traverser, because we need to subclass CountedCompleter.
4785		*/
4786	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException {
4787	<	// force all segments for serialization compatibility
4788	<	for (int k = 0; k < segments.length; ++k)
4789	<	ensureSegment(k);
4790	<	s.defaultWriteObject();
4791	<
4792	<	final Segment<K,V>[] segments = this.segments;
4793	<	for (int k = 0; k < segments.length; ++k) {
4794	<	Segment<K,V> seg = segmentAt(segments, k);
4795	<	seg.lock();
4796	<	try {
4797	<	HashEntry<K,V>[] tab = seg.table;
4798	<	for (int i = 0; i < tab.length; ++i) {
4799	<	HashEntry<K,V> e;
4800	<	for (e = entryAt(tab, i); e != null; e = e.next) {
4801	<	s.writeObject(e.key);
4802	<	s.writeObject(e.value);
4786	>	@SuppressWarnings("serial")
4787	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4788	>	Node<K,V>[] tab;        // same as Traverser
4789	>	Node<K,V> next;
4790	>	TableStack<K,V> stack, spare;
4791	>	int index;
4792	>	int baseIndex;
4793	>	int baseLimit;
4794	>	final int baseSize;
4795	>	int batch;              // split control
4796	>
4797	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4798	>	super(par);
4799	>	this.batch = b;
4800	>	this.index = this.baseIndex = i;
4801	>	if ((this.tab = t) == null)
4802	>	this.baseSize = this.baseLimit = 0;
4803	>	else if (par == null)
4804	>	this.baseSize = this.baseLimit = t.length;
4805	>	else {
4806	>	this.baseLimit = f;
4807	>	this.baseSize = par.baseSize;
4808	>	}
4809	>	}
4810	>
4811	>	/**
4812	>	* Same as Traverser version
4813	>	*/
4814	>	final Node<K,V> advance() {
4815	>	Node<K,V> e;
4816	>	if ((e = next) != null)
4817	>	e = e.next;
4818	>	for (;;) {
4819	>	Node<K,V>[] t; int i, n;
4820	>	if (e != null)
4821	>	return next = e;
4822	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4823	>	(n = t.length) <= (i = index) || i < 0)
4824	>	return next = null;
4825	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4826	>	if (e instanceof ForwardingNode) {
4827	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4828	>	e = null;
4829	>	pushState(t, i, n);
4830	>	continue;
4831		}
4832	+	else if (e instanceof TreeBin)
4833	+	e = ((TreeBin<K,V>)e).first;
4834	+	else
4835	+	e = null;
4836		}
4837	<	} finally {
4838	<	seg.unlock();
4837	>	if (stack != null)
4838	>	recoverState(n);
4839	>	else if ((index = i + baseSize) >= n)
4840	>	index = ++baseIndex;
4841		}
4842		}
4843	<	s.writeObject(null);
4844	<	s.writeObject(null);
4843	>
4844	>	private void pushState(Node<K,V>[] t, int i, int n) {
4845	>	TableStack<K,V> s = spare;
4846	>	if (s != null)
4847	>	spare = s.next;
4848	>	else
4849	>	s = new TableStack<K,V>();
4850	>	s.tab = t;
4851	>	s.length = n;
4852	>	s.index = i;
4853	>	s.next = stack;
4854	>	stack = s;
4855	>	}
4856	>
4857	>	private void recoverState(int n) {
4858	>	TableStack<K,V> s; int len;
4859	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4860	>	n = len;
4861	>	index = s.index;
4862	>	tab = s.tab;
4863	>	s.tab = null;
4864	>	TableStack<K,V> next = s.next;
4865	>	s.next = spare; // save for reuse
4866	>	stack = next;
4867	>	spare = s;
4868	>	}
4869	>	if (s == null && (index += baseSize) >= n)
4870	>	index = ++baseIndex;
4871	>	}
4872		}
4873
4874	<	/**
4875	<	* Reconstitutes the <tt>ConcurrentHashMap</tt> instance from a
4876	<	* stream (i.e., deserializes it).
4877	<	* @param s the stream
4878	<	*/
4879	<	@SuppressWarnings("unchecked")
4880	<	private void readObject(java.io.ObjectInputStream s)
4881	<	throws IOException, ClassNotFoundException {
4882	<	s.defaultReadObject();
4874	>	/*
4875	>	* Task classes. Coded in a regular but ugly format/style to
4876	>	* simplify checks that each variant differs in the right way from
4877	>	* others. The null screenings exist because compilers cannot tell
4878	>	* that we've already null-checked task arguments, so we force
4879	>	* simplest hoisted bypass to help avoid convoluted traps.
4880	>	*/
4881	>	@SuppressWarnings("serial")
4882	>	static final class ForEachKeyTask<K,V>
4883	>	extends BulkTask<K,V,Void> {
4884	>	final Consumer<? super K> action;
4885	>	ForEachKeyTask
4886	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4887	>	Consumer<? super K> action) {
4888	>	super(p, b, i, f, t);
4889	>	this.action = action;
4890	>	}
4891	>	public final void compute() {
4892	>	final Consumer<? super K> action;
4893	>	if ((action = this.action) != null) {
4894	>	for (int i = baseIndex, f, h; batch > 0 &&
4895	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4896	>	addToPendingCount(1);
4897	>	new ForEachKeyTask<K,V>
4898	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4899	>	action).fork();
4900	>	}
4901	>	for (Node<K,V> p; (p = advance()) != null;)
4902	>	action.accept(p.key);
4903	>	propagateCompletion();
4904	>	}
4905	>	}
4906	>	}
4907
4908	<	// Re-initialize segments to be minimally sized, and let grow.
4909	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
4910	<	final Segment<K,V>[] segments = this.segments;
4911	<	for (int k = 0; k < segments.length; ++k) {
4912	<	Segment<K,V> seg = segments[k];
4913	<	if (seg != null) {
4914	<	seg.threshold = (int)(cap * seg.loadFactor);
4915	<	seg.table = (HashEntry<K,V>[]) new HashEntry<?,?>[cap];
4908	>	@SuppressWarnings("serial")
4909	>	static final class ForEachValueTask<K,V>
4910	>	extends BulkTask<K,V,Void> {
4911	>	final Consumer<? super V> action;
4912	>	ForEachValueTask
4913	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4914	>	Consumer<? super V> action) {
4915	>	super(p, b, i, f, t);
4916	>	this.action = action;
4917	>	}
4918	>	public final void compute() {
4919	>	final Consumer<? super V> action;
4920	>	if ((action = this.action) != null) {
4921	>	for (int i = baseIndex, f, h; batch > 0 &&
4922	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4923	>	addToPendingCount(1);
4924	>	new ForEachValueTask<K,V>
4925	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4926	>	action).fork();
4927	>	}
4928	>	for (Node<K,V> p; (p = advance()) != null;)
4929	>	action.accept(p.val);
4930	>	propagateCompletion();
4931		}
4932		}
4933	+	}
4934
4935	<	// Read the keys and values, and put the mappings in the table
4936	<	for (;;) {
4937	<	K key = (K) s.readObject();
4938	<	V value = (V) s.readObject();
4939	<	if (key == null)
4940	<	break;
4941	<	put(key, value);
4935	>	@SuppressWarnings("serial")
4936	>	static final class ForEachEntryTask<K,V>
4937	>	extends BulkTask<K,V,Void> {
4938	>	final Consumer<? super Entry<K,V>> action;
4939	>	ForEachEntryTask
4940	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4941	>	Consumer<? super Entry<K,V>> action) {
4942	>	super(p, b, i, f, t);
4943	>	this.action = action;
4944	>	}
4945	>	public final void compute() {
4946	>	final Consumer<? super Entry<K,V>> action;
4947	>	if ((action = this.action) != null) {
4948	>	for (int i = baseIndex, f, h; batch > 0 &&
4949	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4950	>	addToPendingCount(1);
4951	>	new ForEachEntryTask<K,V>
4952	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4953	>	action).fork();
4954	>	}
4955	>	for (Node<K,V> p; (p = advance()) != null; )
4956	>	action.accept(p);
4957	>	propagateCompletion();
4958	>	}
4959	>	}
4960	>	}
4961	>
4962	>	@SuppressWarnings("serial")
4963	>	static final class ForEachMappingTask<K,V>
4964	>	extends BulkTask<K,V,Void> {
4965	>	final BiConsumer<? super K, ? super V> action;
4966	>	ForEachMappingTask
4967	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4968	>	BiConsumer<? super K,? super V> action) {
4969	>	super(p, b, i, f, t);
4970	>	this.action = action;
4971	>	}
4972	>	public final void compute() {
4973	>	final BiConsumer<? super K, ? super V> action;
4974	>	if ((action = this.action) != null) {
4975	>	for (int i = baseIndex, f, h; batch > 0 &&
4976	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4977	>	addToPendingCount(1);
4978	>	new ForEachMappingTask<K,V>
4979	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4980	>	action).fork();
4981	>	}
4982	>	for (Node<K,V> p; (p = advance()) != null; )
4983	>	action.accept(p.key, p.val);
4984	>	propagateCompletion();
4985	>	}
4986	>	}
4987	>	}
4988	>
4989	>	@SuppressWarnings("serial")
4990	>	static final class ForEachTransformedKeyTask<K,V,U>
4991	>	extends BulkTask<K,V,Void> {
4992	>	final Function<? super K, ? extends U> transformer;
4993	>	final Consumer<? super U> action;
4994	>	ForEachTransformedKeyTask
4995	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4996	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
4997	>	super(p, b, i, f, t);
4998	>	this.transformer = transformer; this.action = action;
4999	>	}
5000	>	public final void compute() {
5001	>	final Function<? super K, ? extends U> transformer;
5002	>	final Consumer<? super U> action;
5003	>	if ((transformer = this.transformer) != null &&
5004	>	(action = this.action) != null) {
5005	>	for (int i = baseIndex, f, h; batch > 0 &&
5006	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5007	>	addToPendingCount(1);
5008	>	new ForEachTransformedKeyTask<K,V,U>
5009	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5010	>	transformer, action).fork();
5011	>	}
5012	>	for (Node<K,V> p; (p = advance()) != null; ) {
5013	>	U u;
5014	>	if ((u = transformer.apply(p.key)) != null)
5015	>	action.accept(u);
5016	>	}
5017	>	propagateCompletion();
5018	>	}
5019	>	}
5020	>	}
5021	>
5022	>	@SuppressWarnings("serial")
5023	>	static final class ForEachTransformedValueTask<K,V,U>
5024	>	extends BulkTask<K,V,Void> {
5025	>	final Function<? super V, ? extends U> transformer;
5026	>	final Consumer<? super U> action;
5027	>	ForEachTransformedValueTask
5028	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5029	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
5030	>	super(p, b, i, f, t);
5031	>	this.transformer = transformer; this.action = action;
5032	>	}
5033	>	public final void compute() {
5034	>	final Function<? super V, ? extends U> transformer;
5035	>	final Consumer<? super U> action;
5036	>	if ((transformer = this.transformer) != null &&
5037	>	(action = this.action) != null) {
5038	>	for (int i = baseIndex, f, h; batch > 0 &&
5039	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5040	>	addToPendingCount(1);
5041	>	new ForEachTransformedValueTask<K,V,U>
5042	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5043	>	transformer, action).fork();
5044	>	}
5045	>	for (Node<K,V> p; (p = advance()) != null; ) {
5046	>	U u;
5047	>	if ((u = transformer.apply(p.val)) != null)
5048	>	action.accept(u);
5049	>	}
5050	>	propagateCompletion();
5051	>	}
5052	>	}
5053	>	}
5054	>
5055	>	@SuppressWarnings("serial")
5056	>	static final class ForEachTransformedEntryTask<K,V,U>
5057	>	extends BulkTask<K,V,Void> {
5058	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5059	>	final Consumer<? super U> action;
5060	>	ForEachTransformedEntryTask
5061	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5062	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5063	>	super(p, b, i, f, t);
5064	>	this.transformer = transformer; this.action = action;
5065	>	}
5066	>	public final void compute() {
5067	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5068	>	final Consumer<? super U> action;
5069	>	if ((transformer = this.transformer) != null &&
5070	>	(action = this.action) != null) {
5071	>	for (int i = baseIndex, f, h; batch > 0 &&
5072	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5073	>	addToPendingCount(1);
5074	>	new ForEachTransformedEntryTask<K,V,U>
5075	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5076	>	transformer, action).fork();
5077	>	}
5078	>	for (Node<K,V> p; (p = advance()) != null; ) {
5079	>	U u;
5080	>	if ((u = transformer.apply(p)) != null)
5081	>	action.accept(u);
5082	>	}
5083	>	propagateCompletion();
5084	>	}
5085	>	}
5086	>	}
5087	>
5088	>	@SuppressWarnings("serial")
5089	>	static final class ForEachTransformedMappingTask<K,V,U>
5090	>	extends BulkTask<K,V,Void> {
5091	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5092	>	final Consumer<? super U> action;
5093	>	ForEachTransformedMappingTask
5094	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5095	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5096	>	Consumer<? super U> action) {
5097	>	super(p, b, i, f, t);
5098	>	this.transformer = transformer; this.action = action;
5099	>	}
5100	>	public final void compute() {
5101	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5102	>	final Consumer<? super U> action;
5103	>	if ((transformer = this.transformer) != null &&
5104	>	(action = this.action) != null) {
5105	>	for (int i = baseIndex, f, h; batch > 0 &&
5106	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5107	>	addToPendingCount(1);
5108	>	new ForEachTransformedMappingTask<K,V,U>
5109	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5110	>	transformer, action).fork();
5111	>	}
5112	>	for (Node<K,V> p; (p = advance()) != null; ) {
5113	>	U u;
5114	>	if ((u = transformer.apply(p.key, p.val)) != null)
5115	>	action.accept(u);
5116	>	}
5117	>	propagateCompletion();
5118	>	}
5119	>	}
5120	>	}
5121	>
5122	>	@SuppressWarnings("serial")
5123	>	static final class SearchKeysTask<K,V,U>
5124	>	extends BulkTask<K,V,U> {
5125	>	final Function<? super K, ? extends U> searchFunction;
5126	>	final AtomicReference<U> result;
5127	>	SearchKeysTask
5128	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5129	>	Function<? super K, ? extends U> searchFunction,
5130	>	AtomicReference<U> result) {
5131	>	super(p, b, i, f, t);
5132	>	this.searchFunction = searchFunction; this.result = result;
5133	>	}
5134	>	public final U getRawResult() { return result.get(); }
5135	>	public final void compute() {
5136	>	final Function<? super K, ? extends U> searchFunction;
5137	>	final AtomicReference<U> result;
5138	>	if ((searchFunction = this.searchFunction) != null &&
5139	>	(result = this.result) != null) {
5140	>	for (int i = baseIndex, f, h; batch > 0 &&
5141	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5142	>	if (result.get() != null)
5143	>	return;
5144	>	addToPendingCount(1);
5145	>	new SearchKeysTask<K,V,U>
5146	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5147	>	searchFunction, result).fork();
5148	>	}
5149	>	while (result.get() == null) {
5150	>	U u;
5151	>	Node<K,V> p;
5152	>	if ((p = advance()) == null) {
5153	>	propagateCompletion();
5154	>	break;
5155	>	}
5156	>	if ((u = searchFunction.apply(p.key)) != null) {
5157	>	if (result.compareAndSet(null, u))
5158	>	quietlyCompleteRoot();
5159	>	break;
5160	>	}
5161	>	}
5162	>	}
5163	>	}
5164	>	}
5165	>
5166	>	@SuppressWarnings("serial")
5167	>	static final class SearchValuesTask<K,V,U>
5168	>	extends BulkTask<K,V,U> {
5169	>	final Function<? super V, ? extends U> searchFunction;
5170	>	final AtomicReference<U> result;
5171	>	SearchValuesTask
5172	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5173	>	Function<? super V, ? extends U> searchFunction,
5174	>	AtomicReference<U> result) {
5175	>	super(p, b, i, f, t);
5176	>	this.searchFunction = searchFunction; this.result = result;
5177	>	}
5178	>	public final U getRawResult() { return result.get(); }
5179	>	public final void compute() {
5180	>	final Function<? super V, ? extends U> searchFunction;
5181	>	final AtomicReference<U> result;
5182	>	if ((searchFunction = this.searchFunction) != null &&
5183	>	(result = this.result) != null) {
5184	>	for (int i = baseIndex, f, h; batch > 0 &&
5185	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5186	>	if (result.get() != null)
5187	>	return;
5188	>	addToPendingCount(1);
5189	>	new SearchValuesTask<K,V,U>
5190	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5191	>	searchFunction, result).fork();
5192	>	}
5193	>	while (result.get() == null) {
5194	>	U u;
5195	>	Node<K,V> p;
5196	>	if ((p = advance()) == null) {
5197	>	propagateCompletion();
5198	>	break;
5199	>	}
5200	>	if ((u = searchFunction.apply(p.val)) != null) {
5201	>	if (result.compareAndSet(null, u))
5202	>	quietlyCompleteRoot();
5203	>	break;
5204	>	}
5205	>	}
5206	>	}
5207	>	}
5208	>	}
5209	>
5210	>	@SuppressWarnings("serial")
5211	>	static final class SearchEntriesTask<K,V,U>
5212	>	extends BulkTask<K,V,U> {
5213	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5214	>	final AtomicReference<U> result;
5215	>	SearchEntriesTask
5216	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5217	>	Function<Entry<K,V>, ? extends U> searchFunction,
5218	>	AtomicReference<U> result) {
5219	>	super(p, b, i, f, t);
5220	>	this.searchFunction = searchFunction; this.result = result;
5221	>	}
5222	>	public final U getRawResult() { return result.get(); }
5223	>	public final void compute() {
5224	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5225	>	final AtomicReference<U> result;
5226	>	if ((searchFunction = this.searchFunction) != null &&
5227	>	(result = this.result) != null) {
5228	>	for (int i = baseIndex, f, h; batch > 0 &&
5229	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5230	>	if (result.get() != null)
5231	>	return;
5232	>	addToPendingCount(1);
5233	>	new SearchEntriesTask<K,V,U>
5234	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5235	>	searchFunction, result).fork();
5236	>	}
5237	>	while (result.get() == null) {
5238	>	U u;
5239	>	Node<K,V> p;
5240	>	if ((p = advance()) == null) {
5241	>	propagateCompletion();
5242	>	break;
5243	>	}
5244	>	if ((u = searchFunction.apply(p)) != null) {
5245	>	if (result.compareAndSet(null, u))
5246	>	quietlyCompleteRoot();
5247	>	return;
5248	>	}
5249	>	}
5250	>	}
5251	>	}
5252	>	}
5253	>
5254	>	@SuppressWarnings("serial")
5255	>	static final class SearchMappingsTask<K,V,U>
5256	>	extends BulkTask<K,V,U> {
5257	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5258	>	final AtomicReference<U> result;
5259	>	SearchMappingsTask
5260	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5261	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5262	>	AtomicReference<U> result) {
5263	>	super(p, b, i, f, t);
5264	>	this.searchFunction = searchFunction; this.result = result;
5265	>	}
5266	>	public final U getRawResult() { return result.get(); }
5267	>	public final void compute() {
5268	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5269	>	final AtomicReference<U> result;
5270	>	if ((searchFunction = this.searchFunction) != null &&
5271	>	(result = this.result) != null) {
5272	>	for (int i = baseIndex, f, h; batch > 0 &&
5273	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5274	>	if (result.get() != null)
5275	>	return;
5276	>	addToPendingCount(1);
5277	>	new SearchMappingsTask<K,V,U>
5278	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5279	>	searchFunction, result).fork();
5280	>	}
5281	>	while (result.get() == null) {
5282	>	U u;
5283	>	Node<K,V> p;
5284	>	if ((p = advance()) == null) {
5285	>	propagateCompletion();
5286	>	break;
5287	>	}
5288	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5289	>	if (result.compareAndSet(null, u))
5290	>	quietlyCompleteRoot();
5291	>	break;
5292	>	}
5293	>	}
5294	>	}
5295	>	}
5296	>	}
5297	>
5298	>	@SuppressWarnings("serial")
5299	>	static final class ReduceKeysTask<K,V>
5300	>	extends BulkTask<K,V,K> {
5301	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5302	>	K result;
5303	>	ReduceKeysTask<K,V> rights, nextRight;
5304	>	ReduceKeysTask
5305	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5306	>	ReduceKeysTask<K,V> nextRight,
5307	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5308	>	super(p, b, i, f, t); this.nextRight = nextRight;
5309	>	this.reducer = reducer;
5310	>	}
5311	>	public final K getRawResult() { return result; }
5312	>	public final void compute() {
5313	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5314	>	if ((reducer = this.reducer) != null) {
5315	>	for (int i = baseIndex, f, h; batch > 0 &&
5316	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5317	>	addToPendingCount(1);
5318	>	(rights = new ReduceKeysTask<K,V>
5319	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5320	>	rights, reducer)).fork();
5321	>	}
5322	>	K r = null;
5323	>	for (Node<K,V> p; (p = advance()) != null; ) {
5324	>	K u = p.key;
5325	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5326	>	}
5327	>	result = r;
5328	>	CountedCompleter<?> c;
5329	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5330	>	@SuppressWarnings("unchecked")
5331	>	ReduceKeysTask<K,V>
5332	>	t = (ReduceKeysTask<K,V>)c,
5333	>	s = t.rights;
5334	>	while (s != null) {
5335	>	K tr, sr;
5336	>	if ((sr = s.result) != null)
5337	>	t.result = (((tr = t.result) == null) ? sr :
5338	>	reducer.apply(tr, sr));
5339	>	s = t.rights = s.nextRight;
5340	>	}
5341	>	}
5342	>	}
5343	>	}
5344	>	}
5345	>
5346	>	@SuppressWarnings("serial")
5347	>	static final class ReduceValuesTask<K,V>
5348	>	extends BulkTask<K,V,V> {
5349	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5350	>	V result;
5351	>	ReduceValuesTask<K,V> rights, nextRight;
5352	>	ReduceValuesTask
5353	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5354	>	ReduceValuesTask<K,V> nextRight,
5355	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5356	>	super(p, b, i, f, t); this.nextRight = nextRight;
5357	>	this.reducer = reducer;
5358	>	}
5359	>	public final V getRawResult() { return result; }
5360	>	public final void compute() {
5361	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5362	>	if ((reducer = this.reducer) != null) {
5363	>	for (int i = baseIndex, f, h; batch > 0 &&
5364	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5365	>	addToPendingCount(1);
5366	>	(rights = new ReduceValuesTask<K,V>
5367	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5368	>	rights, reducer)).fork();
5369	>	}
5370	>	V r = null;
5371	>	for (Node<K,V> p; (p = advance()) != null; ) {
5372	>	V v = p.val;
5373	>	r = (r == null) ? v : reducer.apply(r, v);
5374	>	}
5375	>	result = r;
5376	>	CountedCompleter<?> c;
5377	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5378	>	@SuppressWarnings("unchecked")
5379	>	ReduceValuesTask<K,V>
5380	>	t = (ReduceValuesTask<K,V>)c,
5381	>	s = t.rights;
5382	>	while (s != null) {
5383	>	V tr, sr;
5384	>	if ((sr = s.result) != null)
5385	>	t.result = (((tr = t.result) == null) ? sr :
5386	>	reducer.apply(tr, sr));
5387	>	s = t.rights = s.nextRight;
5388	>	}
5389	>	}
5390	>	}
5391	>	}
5392	>	}
5393	>
5394	>	@SuppressWarnings("serial")
5395	>	static final class ReduceEntriesTask<K,V>
5396	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5397	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5398	>	Map.Entry<K,V> result;
5399	>	ReduceEntriesTask<K,V> rights, nextRight;
5400	>	ReduceEntriesTask
5401	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5402	>	ReduceEntriesTask<K,V> nextRight,
5403	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5404	>	super(p, b, i, f, t); this.nextRight = nextRight;
5405	>	this.reducer = reducer;
5406	>	}
5407	>	public final Map.Entry<K,V> getRawResult() { return result; }
5408	>	public final void compute() {
5409	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5410	>	if ((reducer = this.reducer) != null) {
5411	>	for (int i = baseIndex, f, h; batch > 0 &&
5412	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5413	>	addToPendingCount(1);
5414	>	(rights = new ReduceEntriesTask<K,V>
5415	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5416	>	rights, reducer)).fork();
5417	>	}
5418	>	Map.Entry<K,V> r = null;
5419	>	for (Node<K,V> p; (p = advance()) != null; )
5420	>	r = (r == null) ? p : reducer.apply(r, p);
5421	>	result = r;
5422	>	CountedCompleter<?> c;
5423	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5424	>	@SuppressWarnings("unchecked")
5425	>	ReduceEntriesTask<K,V>
5426	>	t = (ReduceEntriesTask<K,V>)c,
5427	>	s = t.rights;
5428	>	while (s != null) {
5429	>	Map.Entry<K,V> tr, sr;
5430	>	if ((sr = s.result) != null)
5431	>	t.result = (((tr = t.result) == null) ? sr :
5432	>	reducer.apply(tr, sr));
5433	>	s = t.rights = s.nextRight;
5434	>	}
5435	>	}
5436	>	}
5437	>	}
5438	>	}
5439	>
5440	>	@SuppressWarnings("serial")
5441	>	static final class MapReduceKeysTask<K,V,U>
5442	>	extends BulkTask<K,V,U> {
5443	>	final Function<? super K, ? extends U> transformer;
5444	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5445	>	U result;
5446	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5447	>	MapReduceKeysTask
5448	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5449	>	MapReduceKeysTask<K,V,U> nextRight,
5450	>	Function<? super K, ? extends U> transformer,
5451	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5452	>	super(p, b, i, f, t); this.nextRight = nextRight;
5453	>	this.transformer = transformer;
5454	>	this.reducer = reducer;
5455	>	}
5456	>	public final U getRawResult() { return result; }
5457	>	public final void compute() {
5458	>	final Function<? super K, ? extends U> transformer;
5459	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5460	>	if ((transformer = this.transformer) != null &&
5461	>	(reducer = this.reducer) != null) {
5462	>	for (int i = baseIndex, f, h; batch > 0 &&
5463	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5464	>	addToPendingCount(1);
5465	>	(rights = new MapReduceKeysTask<K,V,U>
5466	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5467	>	rights, transformer, reducer)).fork();
5468	>	}
5469	>	U r = null;
5470	>	for (Node<K,V> p; (p = advance()) != null; ) {
5471	>	U u;
5472	>	if ((u = transformer.apply(p.key)) != null)
5473	>	r = (r == null) ? u : reducer.apply(r, u);
5474	>	}
5475	>	result = r;
5476	>	CountedCompleter<?> c;
5477	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5478	>	@SuppressWarnings("unchecked")
5479	>	MapReduceKeysTask<K,V,U>
5480	>	t = (MapReduceKeysTask<K,V,U>)c,
5481	>	s = t.rights;
5482	>	while (s != null) {
5483	>	U tr, sr;
5484	>	if ((sr = s.result) != null)
5485	>	t.result = (((tr = t.result) == null) ? sr :
5486	>	reducer.apply(tr, sr));
5487	>	s = t.rights = s.nextRight;
5488	>	}
5489	>	}
5490	>	}
5491	>	}
5492	>	}
5493	>
5494	>	@SuppressWarnings("serial")
5495	>	static final class MapReduceValuesTask<K,V,U>
5496	>	extends BulkTask<K,V,U> {
5497	>	final Function<? super V, ? extends U> transformer;
5498	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5499	>	U result;
5500	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5501	>	MapReduceValuesTask
5502	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5503	>	MapReduceValuesTask<K,V,U> nextRight,
5504	>	Function<? super V, ? extends U> transformer,
5505	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5506	>	super(p, b, i, f, t); this.nextRight = nextRight;
5507	>	this.transformer = transformer;
5508	>	this.reducer = reducer;
5509	>	}
5510	>	public final U getRawResult() { return result; }
5511	>	public final void compute() {
5512	>	final Function<? super V, ? extends U> transformer;
5513	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5514	>	if ((transformer = this.transformer) != null &&
5515	>	(reducer = this.reducer) != null) {
5516	>	for (int i = baseIndex, f, h; batch > 0 &&
5517	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5518	>	addToPendingCount(1);
5519	>	(rights = new MapReduceValuesTask<K,V,U>
5520	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5521	>	rights, transformer, reducer)).fork();
5522	>	}
5523	>	U r = null;
5524	>	for (Node<K,V> p; (p = advance()) != null; ) {
5525	>	U u;
5526	>	if ((u = transformer.apply(p.val)) != null)
5527	>	r = (r == null) ? u : reducer.apply(r, u);
5528	>	}
5529	>	result = r;
5530	>	CountedCompleter<?> c;
5531	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5532	>	@SuppressWarnings("unchecked")
5533	>	MapReduceValuesTask<K,V,U>
5534	>	t = (MapReduceValuesTask<K,V,U>)c,
5535	>	s = t.rights;
5536	>	while (s != null) {
5537	>	U tr, sr;
5538	>	if ((sr = s.result) != null)
5539	>	t.result = (((tr = t.result) == null) ? sr :
5540	>	reducer.apply(tr, sr));
5541	>	s = t.rights = s.nextRight;
5542	>	}
5543	>	}
5544	>	}
5545	>	}
5546	>	}
5547	>
5548	>	@SuppressWarnings("serial")
5549	>	static final class MapReduceEntriesTask<K,V,U>
5550	>	extends BulkTask<K,V,U> {
5551	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5552	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5553	>	U result;
5554	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5555	>	MapReduceEntriesTask
5556	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5557	>	MapReduceEntriesTask<K,V,U> nextRight,
5558	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5559	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5560	>	super(p, b, i, f, t); this.nextRight = nextRight;
5561	>	this.transformer = transformer;
5562	>	this.reducer = reducer;
5563	>	}
5564	>	public final U getRawResult() { return result; }
5565	>	public final void compute() {
5566	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5567	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5568	>	if ((transformer = this.transformer) != null &&
5569	>	(reducer = this.reducer) != null) {
5570	>	for (int i = baseIndex, f, h; batch > 0 &&
5571	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5572	>	addToPendingCount(1);
5573	>	(rights = new MapReduceEntriesTask<K,V,U>
5574	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5575	>	rights, transformer, reducer)).fork();
5576	>	}
5577	>	U r = null;
5578	>	for (Node<K,V> p; (p = advance()) != null; ) {
5579	>	U u;
5580	>	if ((u = transformer.apply(p)) != null)
5581	>	r = (r == null) ? u : reducer.apply(r, u);
5582	>	}
5583	>	result = r;
5584	>	CountedCompleter<?> c;
5585	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5586	>	@SuppressWarnings("unchecked")
5587	>	MapReduceEntriesTask<K,V,U>
5588	>	t = (MapReduceEntriesTask<K,V,U>)c,
5589	>	s = t.rights;
5590	>	while (s != null) {
5591	>	U tr, sr;
5592	>	if ((sr = s.result) != null)
5593	>	t.result = (((tr = t.result) == null) ? sr :
5594	>	reducer.apply(tr, sr));
5595	>	s = t.rights = s.nextRight;
5596	>	}
5597	>	}
5598	>	}
5599	>	}
5600	>	}
5601	>
5602	>	@SuppressWarnings("serial")
5603	>	static final class MapReduceMappingsTask<K,V,U>
5604	>	extends BulkTask<K,V,U> {
5605	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5606	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5607	>	U result;
5608	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5609	>	MapReduceMappingsTask
5610	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5611	>	MapReduceMappingsTask<K,V,U> nextRight,
5612	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5613	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5614	>	super(p, b, i, f, t); this.nextRight = nextRight;
5615	>	this.transformer = transformer;
5616	>	this.reducer = reducer;
5617	>	}
5618	>	public final U getRawResult() { return result; }
5619	>	public final void compute() {
5620	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5621	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5622	>	if ((transformer = this.transformer) != null &&
5623	>	(reducer = this.reducer) != null) {
5624	>	for (int i = baseIndex, f, h; batch > 0 &&
5625	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5626	>	addToPendingCount(1);
5627	>	(rights = new MapReduceMappingsTask<K,V,U>
5628	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5629	>	rights, transformer, reducer)).fork();
5630	>	}
5631	>	U r = null;
5632	>	for (Node<K,V> p; (p = advance()) != null; ) {
5633	>	U u;
5634	>	if ((u = transformer.apply(p.key, p.val)) != null)
5635	>	r = (r == null) ? u : reducer.apply(r, u);
5636	>	}
5637	>	result = r;
5638	>	CountedCompleter<?> c;
5639	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5640	>	@SuppressWarnings("unchecked")
5641	>	MapReduceMappingsTask<K,V,U>
5642	>	t = (MapReduceMappingsTask<K,V,U>)c,
5643	>	s = t.rights;
5644	>	while (s != null) {
5645	>	U tr, sr;
5646	>	if ((sr = s.result) != null)
5647	>	t.result = (((tr = t.result) == null) ? sr :
5648	>	reducer.apply(tr, sr));
5649	>	s = t.rights = s.nextRight;
5650	>	}
5651	>	}
5652	>	}
5653	>	}
5654	>	}
5655	>
5656	>	@SuppressWarnings("serial")
5657	>	static final class MapReduceKeysToDoubleTask<K,V>
5658	>	extends BulkTask<K,V,Double> {
5659	>	final ToDoubleFunction<? super K> transformer;
5660	>	final DoubleBinaryOperator reducer;
5661	>	final double basis;
5662	>	double result;
5663	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5664	>	MapReduceKeysToDoubleTask
5665	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5666	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5667	>	ToDoubleFunction<? super K> transformer,
5668	>	double basis,
5669	>	DoubleBinaryOperator reducer) {
5670	>	super(p, b, i, f, t); this.nextRight = nextRight;
5671	>	this.transformer = transformer;
5672	>	this.basis = basis; this.reducer = reducer;
5673	>	}
5674	>	public final Double getRawResult() { return result; }
5675	>	public final void compute() {
5676	>	final ToDoubleFunction<? super K> transformer;
5677	>	final DoubleBinaryOperator reducer;
5678	>	if ((transformer = this.transformer) != null &&
5679	>	(reducer = this.reducer) != null) {
5680	>	double r = this.basis;
5681	>	for (int i = baseIndex, f, h; batch > 0 &&
5682	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5683	>	addToPendingCount(1);
5684	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5685	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5686	>	rights, transformer, r, reducer)).fork();
5687	>	}
5688	>	for (Node<K,V> p; (p = advance()) != null; )
5689	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5690	>	result = r;
5691	>	CountedCompleter<?> c;
5692	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5693	>	@SuppressWarnings("unchecked")
5694	>	MapReduceKeysToDoubleTask<K,V>
5695	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5696	>	s = t.rights;
5697	>	while (s != null) {
5698	>	t.result = reducer.applyAsDouble(t.result, s.result);
5699	>	s = t.rights = s.nextRight;
5700	>	}
5701	>	}
5702	>	}
5703	>	}
5704	>	}
5705	>
5706	>	@SuppressWarnings("serial")
5707	>	static final class MapReduceValuesToDoubleTask<K,V>
5708	>	extends BulkTask<K,V,Double> {
5709	>	final ToDoubleFunction<? super V> transformer;
5710	>	final DoubleBinaryOperator reducer;
5711	>	final double basis;
5712	>	double result;
5713	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5714	>	MapReduceValuesToDoubleTask
5715	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5716	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5717	>	ToDoubleFunction<? super V> transformer,
5718	>	double basis,
5719	>	DoubleBinaryOperator reducer) {
5720	>	super(p, b, i, f, t); this.nextRight = nextRight;
5721	>	this.transformer = transformer;
5722	>	this.basis = basis; this.reducer = reducer;
5723	>	}
5724	>	public final Double getRawResult() { return result; }
5725	>	public final void compute() {
5726	>	final ToDoubleFunction<? super V> transformer;
5727	>	final DoubleBinaryOperator reducer;
5728	>	if ((transformer = this.transformer) != null &&
5729	>	(reducer = this.reducer) != null) {
5730	>	double r = this.basis;
5731	>	for (int i = baseIndex, f, h; batch > 0 &&
5732	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5733	>	addToPendingCount(1);
5734	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5735	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5736	>	rights, transformer, r, reducer)).fork();
5737	>	}
5738	>	for (Node<K,V> p; (p = advance()) != null; )
5739	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5740	>	result = r;
5741	>	CountedCompleter<?> c;
5742	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5743	>	@SuppressWarnings("unchecked")
5744	>	MapReduceValuesToDoubleTask<K,V>
5745	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5746	>	s = t.rights;
5747	>	while (s != null) {
5748	>	t.result = reducer.applyAsDouble(t.result, s.result);
5749	>	s = t.rights = s.nextRight;
5750	>	}
5751	>	}
5752	>	}
5753	>	}
5754	>	}
5755	>
5756	>	@SuppressWarnings("serial")
5757	>	static final class MapReduceEntriesToDoubleTask<K,V>
5758	>	extends BulkTask<K,V,Double> {
5759	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5760	>	final DoubleBinaryOperator reducer;
5761	>	final double basis;
5762	>	double result;
5763	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5764	>	MapReduceEntriesToDoubleTask
5765	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5766	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5767	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5768	>	double basis,
5769	>	DoubleBinaryOperator reducer) {
5770	>	super(p, b, i, f, t); this.nextRight = nextRight;
5771	>	this.transformer = transformer;
5772	>	this.basis = basis; this.reducer = reducer;
5773	>	}
5774	>	public final Double getRawResult() { return result; }
5775	>	public final void compute() {
5776	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5777	>	final DoubleBinaryOperator reducer;
5778	>	if ((transformer = this.transformer) != null &&
5779	>	(reducer = this.reducer) != null) {
5780	>	double r = this.basis;
5781	>	for (int i = baseIndex, f, h; batch > 0 &&
5782	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5783	>	addToPendingCount(1);
5784	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5785	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5786	>	rights, transformer, r, reducer)).fork();
5787	>	}
5788	>	for (Node<K,V> p; (p = advance()) != null; )
5789	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5790	>	result = r;
5791	>	CountedCompleter<?> c;
5792	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5793	>	@SuppressWarnings("unchecked")
5794	>	MapReduceEntriesToDoubleTask<K,V>
5795	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5796	>	s = t.rights;
5797	>	while (s != null) {
5798	>	t.result = reducer.applyAsDouble(t.result, s.result);
5799	>	s = t.rights = s.nextRight;
5800	>	}
5801	>	}
5802	>	}
5803	>	}
5804	>	}
5805	>
5806	>	@SuppressWarnings("serial")
5807	>	static final class MapReduceMappingsToDoubleTask<K,V>
5808	>	extends BulkTask<K,V,Double> {
5809	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5810	>	final DoubleBinaryOperator reducer;
5811	>	final double basis;
5812	>	double result;
5813	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5814	>	MapReduceMappingsToDoubleTask
5815	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5816	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5817	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5818	>	double basis,
5819	>	DoubleBinaryOperator reducer) {
5820	>	super(p, b, i, f, t); this.nextRight = nextRight;
5821	>	this.transformer = transformer;
5822	>	this.basis = basis; this.reducer = reducer;
5823	>	}
5824	>	public final Double getRawResult() { return result; }
5825	>	public final void compute() {
5826	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5827	>	final DoubleBinaryOperator reducer;
5828	>	if ((transformer = this.transformer) != null &&
5829	>	(reducer = this.reducer) != null) {
5830	>	double r = this.basis;
5831	>	for (int i = baseIndex, f, h; batch > 0 &&
5832	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5833	>	addToPendingCount(1);
5834	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5835	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5836	>	rights, transformer, r, reducer)).fork();
5837	>	}
5838	>	for (Node<K,V> p; (p = advance()) != null; )
5839	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5840	>	result = r;
5841	>	CountedCompleter<?> c;
5842	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5843	>	@SuppressWarnings("unchecked")
5844	>	MapReduceMappingsToDoubleTask<K,V>
5845	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5846	>	s = t.rights;
5847	>	while (s != null) {
5848	>	t.result = reducer.applyAsDouble(t.result, s.result);
5849	>	s = t.rights = s.nextRight;
5850	>	}
5851	>	}
5852	>	}
5853	>	}
5854	>	}
5855	>
5856	>	@SuppressWarnings("serial")
5857	>	static final class MapReduceKeysToLongTask<K,V>
5858	>	extends BulkTask<K,V,Long> {
5859	>	final ToLongFunction<? super K> transformer;
5860	>	final LongBinaryOperator reducer;
5861	>	final long basis;
5862	>	long result;
5863	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5864	>	MapReduceKeysToLongTask
5865	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5866	>	MapReduceKeysToLongTask<K,V> nextRight,
5867	>	ToLongFunction<? super K> transformer,
5868	>	long basis,
5869	>	LongBinaryOperator reducer) {
5870	>	super(p, b, i, f, t); this.nextRight = nextRight;
5871	>	this.transformer = transformer;
5872	>	this.basis = basis; this.reducer = reducer;
5873	>	}
5874	>	public final Long getRawResult() { return result; }
5875	>	public final void compute() {
5876	>	final ToLongFunction<? super K> transformer;
5877	>	final LongBinaryOperator reducer;
5878	>	if ((transformer = this.transformer) != null &&
5879	>	(reducer = this.reducer) != null) {
5880	>	long r = this.basis;
5881	>	for (int i = baseIndex, f, h; batch > 0 &&
5882	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5883	>	addToPendingCount(1);
5884	>	(rights = new MapReduceKeysToLongTask<K,V>
5885	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5886	>	rights, transformer, r, reducer)).fork();
5887	>	}
5888	>	for (Node<K,V> p; (p = advance()) != null; )
5889	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5890	>	result = r;
5891	>	CountedCompleter<?> c;
5892	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5893	>	@SuppressWarnings("unchecked")
5894	>	MapReduceKeysToLongTask<K,V>
5895	>	t = (MapReduceKeysToLongTask<K,V>)c,
5896	>	s = t.rights;
5897	>	while (s != null) {
5898	>	t.result = reducer.applyAsLong(t.result, s.result);
5899	>	s = t.rights = s.nextRight;
5900	>	}
5901	>	}
5902	>	}
5903	>	}
5904	>	}
5905	>
5906	>	@SuppressWarnings("serial")
5907	>	static final class MapReduceValuesToLongTask<K,V>
5908	>	extends BulkTask<K,V,Long> {
5909	>	final ToLongFunction<? super V> transformer;
5910	>	final LongBinaryOperator reducer;
5911	>	final long basis;
5912	>	long result;
5913	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5914	>	MapReduceValuesToLongTask
5915	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5916	>	MapReduceValuesToLongTask<K,V> nextRight,
5917	>	ToLongFunction<? super V> transformer,
5918	>	long basis,
5919	>	LongBinaryOperator reducer) {
5920	>	super(p, b, i, f, t); this.nextRight = nextRight;
5921	>	this.transformer = transformer;
5922	>	this.basis = basis; this.reducer = reducer;
5923	>	}
5924	>	public final Long getRawResult() { return result; }
5925	>	public final void compute() {
5926	>	final ToLongFunction<? super V> transformer;
5927	>	final LongBinaryOperator reducer;
5928	>	if ((transformer = this.transformer) != null &&
5929	>	(reducer = this.reducer) != null) {
5930	>	long r = this.basis;
5931	>	for (int i = baseIndex, f, h; batch > 0 &&
5932	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5933	>	addToPendingCount(1);
5934	>	(rights = new MapReduceValuesToLongTask<K,V>
5935	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5936	>	rights, transformer, r, reducer)).fork();
5937	>	}
5938	>	for (Node<K,V> p; (p = advance()) != null; )
5939	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
5940	>	result = r;
5941	>	CountedCompleter<?> c;
5942	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5943	>	@SuppressWarnings("unchecked")
5944	>	MapReduceValuesToLongTask<K,V>
5945	>	t = (MapReduceValuesToLongTask<K,V>)c,
5946	>	s = t.rights;
5947	>	while (s != null) {
5948	>	t.result = reducer.applyAsLong(t.result, s.result);
5949	>	s = t.rights = s.nextRight;
5950	>	}
5951	>	}
5952	>	}
5953	>	}
5954	>	}
5955	>
5956	>	@SuppressWarnings("serial")
5957	>	static final class MapReduceEntriesToLongTask<K,V>
5958	>	extends BulkTask<K,V,Long> {
5959	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5960	>	final LongBinaryOperator reducer;
5961	>	final long basis;
5962	>	long result;
5963	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
5964	>	MapReduceEntriesToLongTask
5965	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5966	>	MapReduceEntriesToLongTask<K,V> nextRight,
5967	>	ToLongFunction<Map.Entry<K,V>> transformer,
5968	>	long basis,
5969	>	LongBinaryOperator reducer) {
5970	>	super(p, b, i, f, t); this.nextRight = nextRight;
5971	>	this.transformer = transformer;
5972	>	this.basis = basis; this.reducer = reducer;
5973	>	}
5974	>	public final Long getRawResult() { return result; }
5975	>	public final void compute() {
5976	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5977	>	final LongBinaryOperator reducer;
5978	>	if ((transformer = this.transformer) != null &&
5979	>	(reducer = this.reducer) != null) {
5980	>	long r = this.basis;
5981	>	for (int i = baseIndex, f, h; batch > 0 &&
5982	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5983	>	addToPendingCount(1);
5984	>	(rights = new MapReduceEntriesToLongTask<K,V>
5985	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5986	>	rights, transformer, r, reducer)).fork();
5987	>	}
5988	>	for (Node<K,V> p; (p = advance()) != null; )
5989	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
5990	>	result = r;
5991	>	CountedCompleter<?> c;
5992	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5993	>	@SuppressWarnings("unchecked")
5994	>	MapReduceEntriesToLongTask<K,V>
5995	>	t = (MapReduceEntriesToLongTask<K,V>)c,
5996	>	s = t.rights;
5997	>	while (s != null) {
5998	>	t.result = reducer.applyAsLong(t.result, s.result);
5999	>	s = t.rights = s.nextRight;
6000	>	}
6001	>	}
6002	>	}
6003	>	}
6004	>	}
6005	>
6006	>	@SuppressWarnings("serial")
6007	>	static final class MapReduceMappingsToLongTask<K,V>
6008	>	extends BulkTask<K,V,Long> {
6009	>	final ToLongBiFunction<? super K, ? super V> transformer;
6010	>	final LongBinaryOperator reducer;
6011	>	final long basis;
6012	>	long result;
6013	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
6014	>	MapReduceMappingsToLongTask
6015	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6016	>	MapReduceMappingsToLongTask<K,V> nextRight,
6017	>	ToLongBiFunction<? super K, ? super V> transformer,
6018	>	long basis,
6019	>	LongBinaryOperator reducer) {
6020	>	super(p, b, i, f, t); this.nextRight = nextRight;
6021	>	this.transformer = transformer;
6022	>	this.basis = basis; this.reducer = reducer;
6023	>	}
6024	>	public final Long getRawResult() { return result; }
6025	>	public final void compute() {
6026	>	final ToLongBiFunction<? super K, ? super V> transformer;
6027	>	final LongBinaryOperator reducer;
6028	>	if ((transformer = this.transformer) != null &&
6029	>	(reducer = this.reducer) != null) {
6030	>	long r = this.basis;
6031	>	for (int i = baseIndex, f, h; batch > 0 &&
6032	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6033	>	addToPendingCount(1);
6034	>	(rights = new MapReduceMappingsToLongTask<K,V>
6035	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6036	>	rights, transformer, r, reducer)).fork();
6037	>	}
6038	>	for (Node<K,V> p; (p = advance()) != null; )
6039	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
6040	>	result = r;
6041	>	CountedCompleter<?> c;
6042	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6043	>	@SuppressWarnings("unchecked")
6044	>	MapReduceMappingsToLongTask<K,V>
6045	>	t = (MapReduceMappingsToLongTask<K,V>)c,
6046	>	s = t.rights;
6047	>	while (s != null) {
6048	>	t.result = reducer.applyAsLong(t.result, s.result);
6049	>	s = t.rights = s.nextRight;
6050	>	}
6051	>	}
6052	>	}
6053	>	}
6054	>	}
6055	>
6056	>	@SuppressWarnings("serial")
6057	>	static final class MapReduceKeysToIntTask<K,V>
6058	>	extends BulkTask<K,V,Integer> {
6059	>	final ToIntFunction<? super K> transformer;
6060	>	final IntBinaryOperator reducer;
6061	>	final int basis;
6062	>	int result;
6063	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6064	>	MapReduceKeysToIntTask
6065	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6066	>	MapReduceKeysToIntTask<K,V> nextRight,
6067	>	ToIntFunction<? super K> transformer,
6068	>	int basis,
6069	>	IntBinaryOperator reducer) {
6070	>	super(p, b, i, f, t); this.nextRight = nextRight;
6071	>	this.transformer = transformer;
6072	>	this.basis = basis; this.reducer = reducer;
6073	>	}
6074	>	public final Integer getRawResult() { return result; }
6075	>	public final void compute() {
6076	>	final ToIntFunction<? super K> transformer;
6077	>	final IntBinaryOperator reducer;
6078	>	if ((transformer = this.transformer) != null &&
6079	>	(reducer = this.reducer) != null) {
6080	>	int r = this.basis;
6081	>	for (int i = baseIndex, f, h; batch > 0 &&
6082	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6083	>	addToPendingCount(1);
6084	>	(rights = new MapReduceKeysToIntTask<K,V>
6085	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6086	>	rights, transformer, r, reducer)).fork();
6087	>	}
6088	>	for (Node<K,V> p; (p = advance()) != null; )
6089	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6090	>	result = r;
6091	>	CountedCompleter<?> c;
6092	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6093	>	@SuppressWarnings("unchecked")
6094	>	MapReduceKeysToIntTask<K,V>
6095	>	t = (MapReduceKeysToIntTask<K,V>)c,
6096	>	s = t.rights;
6097	>	while (s != null) {
6098	>	t.result = reducer.applyAsInt(t.result, s.result);
6099	>	s = t.rights = s.nextRight;
6100	>	}
6101	>	}
6102	>	}
6103	>	}
6104	>	}
6105	>
6106	>	@SuppressWarnings("serial")
6107	>	static final class MapReduceValuesToIntTask<K,V>
6108	>	extends BulkTask<K,V,Integer> {
6109	>	final ToIntFunction<? super V> transformer;
6110	>	final IntBinaryOperator reducer;
6111	>	final int basis;
6112	>	int result;
6113	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6114	>	MapReduceValuesToIntTask
6115	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6116	>	MapReduceValuesToIntTask<K,V> nextRight,
6117	>	ToIntFunction<? super V> transformer,
6118	>	int basis,
6119	>	IntBinaryOperator reducer) {
6120	>	super(p, b, i, f, t); this.nextRight = nextRight;
6121	>	this.transformer = transformer;
6122	>	this.basis = basis; this.reducer = reducer;
6123	>	}
6124	>	public final Integer getRawResult() { return result; }
6125	>	public final void compute() {
6126	>	final ToIntFunction<? super V> transformer;
6127	>	final IntBinaryOperator reducer;
6128	>	if ((transformer = this.transformer) != null &&
6129	>	(reducer = this.reducer) != null) {
6130	>	int r = this.basis;
6131	>	for (int i = baseIndex, f, h; batch > 0 &&
6132	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6133	>	addToPendingCount(1);
6134	>	(rights = new MapReduceValuesToIntTask<K,V>
6135	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6136	>	rights, transformer, r, reducer)).fork();
6137	>	}
6138	>	for (Node<K,V> p; (p = advance()) != null; )
6139	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6140	>	result = r;
6141	>	CountedCompleter<?> c;
6142	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6143	>	@SuppressWarnings("unchecked")
6144	>	MapReduceValuesToIntTask<K,V>
6145	>	t = (MapReduceValuesToIntTask<K,V>)c,
6146	>	s = t.rights;
6147	>	while (s != null) {
6148	>	t.result = reducer.applyAsInt(t.result, s.result);
6149	>	s = t.rights = s.nextRight;
6150	>	}
6151	>	}
6152	>	}
6153	>	}
6154	>	}
6155	>
6156	>	@SuppressWarnings("serial")
6157	>	static final class MapReduceEntriesToIntTask<K,V>
6158	>	extends BulkTask<K,V,Integer> {
6159	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6160	>	final IntBinaryOperator reducer;
6161	>	final int basis;
6162	>	int result;
6163	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6164	>	MapReduceEntriesToIntTask
6165	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6166	>	MapReduceEntriesToIntTask<K,V> nextRight,
6167	>	ToIntFunction<Map.Entry<K,V>> transformer,
6168	>	int basis,
6169	>	IntBinaryOperator reducer) {
6170	>	super(p, b, i, f, t); this.nextRight = nextRight;
6171	>	this.transformer = transformer;
6172	>	this.basis = basis; this.reducer = reducer;
6173	>	}
6174	>	public final Integer getRawResult() { return result; }
6175	>	public final void compute() {
6176	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6177	>	final IntBinaryOperator reducer;
6178	>	if ((transformer = this.transformer) != null &&
6179	>	(reducer = this.reducer) != null) {
6180	>	int r = this.basis;
6181	>	for (int i = baseIndex, f, h; batch > 0 &&
6182	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6183	>	addToPendingCount(1);
6184	>	(rights = new MapReduceEntriesToIntTask<K,V>
6185	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6186	>	rights, transformer, r, reducer)).fork();
6187	>	}
6188	>	for (Node<K,V> p; (p = advance()) != null; )
6189	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6190	>	result = r;
6191	>	CountedCompleter<?> c;
6192	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6193	>	@SuppressWarnings("unchecked")
6194	>	MapReduceEntriesToIntTask<K,V>
6195	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6196	>	s = t.rights;
6197	>	while (s != null) {
6198	>	t.result = reducer.applyAsInt(t.result, s.result);
6199	>	s = t.rights = s.nextRight;
6200	>	}
6201	>	}
6202	>	}
6203	>	}
6204	>	}
6205	>
6206	>	@SuppressWarnings("serial")
6207	>	static final class MapReduceMappingsToIntTask<K,V>
6208	>	extends BulkTask<K,V,Integer> {
6209	>	final ToIntBiFunction<? super K, ? super V> transformer;
6210	>	final IntBinaryOperator reducer;
6211	>	final int basis;
6212	>	int result;
6213	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6214	>	MapReduceMappingsToIntTask
6215	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6216	>	MapReduceMappingsToIntTask<K,V> nextRight,
6217	>	ToIntBiFunction<? super K, ? super V> transformer,
6218	>	int basis,
6219	>	IntBinaryOperator reducer) {
6220	>	super(p, b, i, f, t); this.nextRight = nextRight;
6221	>	this.transformer = transformer;
6222	>	this.basis = basis; this.reducer = reducer;
6223	>	}
6224	>	public final Integer getRawResult() { return result; }
6225	>	public final void compute() {
6226	>	final ToIntBiFunction<? super K, ? super V> transformer;
6227	>	final IntBinaryOperator reducer;
6228	>	if ((transformer = this.transformer) != null &&
6229	>	(reducer = this.reducer) != null) {
6230	>	int r = this.basis;
6231	>	for (int i = baseIndex, f, h; batch > 0 &&
6232	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6233	>	addToPendingCount(1);
6234	>	(rights = new MapReduceMappingsToIntTask<K,V>
6235	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6236	>	rights, transformer, r, reducer)).fork();
6237	>	}
6238	>	for (Node<K,V> p; (p = advance()) != null; )
6239	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6240	>	result = r;
6241	>	CountedCompleter<?> c;
6242	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6243	>	@SuppressWarnings("unchecked")
6244	>	MapReduceMappingsToIntTask<K,V>
6245	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6246	>	s = t.rights;
6247	>	while (s != null) {
6248	>	t.result = reducer.applyAsInt(t.result, s.result);
6249	>	s = t.rights = s.nextRight;
6250	>	}
6251	>	}
6252	>	}
6253		}
6254		}
6255
6256		// Unsafe mechanics
6257	<	private static final sun.misc.Unsafe UNSAFE;
6258	<	private static final long SBASE;
6259	<	private static final int SSHIFT;
6260	<	private static final long TBASE;
6261	<	private static final int TSHIFT;
6257	>	private static final sun.misc.Unsafe U = sun.misc.Unsafe.getUnsafe();
6258	>	private static final long SIZECTL;
6259	>	private static final long TRANSFERINDEX;
6260	>	private static final long BASECOUNT;
6261	>	private static final long CELLSBUSY;
6262	>	private static final long CELLVALUE;
6263	>	private static final int ABASE;
6264	>	private static final int ASHIFT;
6265
6266		static {
1466	–	int ss, ts;
6267		try {
6268	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
6269	<	Class<?> tc = HashEntry[].class;
6270	<	Class<?> sc = Segment[].class;
6271	<	TBASE = UNSAFE.arrayBaseOffset(tc);
6272	<	SBASE = UNSAFE.arrayBaseOffset(sc);
6273	<	ts = UNSAFE.arrayIndexScale(tc);
6274	<	ss = UNSAFE.arrayIndexScale(sc);
6275	<	} catch (Exception e) {
6268	>	SIZECTL = U.objectFieldOffset
6269	>	(ConcurrentHashMap.class.getDeclaredField("sizeCtl"));
6270	>	TRANSFERINDEX = U.objectFieldOffset
6271	>	(ConcurrentHashMap.class.getDeclaredField("transferIndex"));
6272	>	BASECOUNT = U.objectFieldOffset
6273	>	(ConcurrentHashMap.class.getDeclaredField("baseCount"));
6274	>	CELLSBUSY = U.objectFieldOffset
6275	>	(ConcurrentHashMap.class.getDeclaredField("cellsBusy"));
6276	>
6277	>	CELLVALUE = U.objectFieldOffset
6278	>	(CounterCell.class.getDeclaredField("value"));
6279	>
6280	>	ABASE = U.arrayBaseOffset(Node[].class);
6281	>	int scale = U.arrayIndexScale(Node[].class);
6282	>	if ((scale & (scale - 1)) != 0)
6283	>	throw new Error("array index scale not a power of two");
6284	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6285	>	} catch (ReflectiveOperationException e) {
6286		throw new Error(e);
6287		}
1478	–	if ((ss & (ss-1)) != 0 || (ts & (ts-1)) != 0)
1479	–	throw new Error("data type scale not a power of two");
1480	–	SSHIFT = 31 - Integer.numberOfLeadingZeros(ss);
1481	–	TSHIFT = 31 - Integer.numberOfLeadingZeros(ts);
6288		}
1483	–
6289		}

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