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Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.115 by jsr166, Fri Dec 2 14:28:17 2011 UTC vs.
Revision 1.251 by dl, Wed Sep 4 00:02:46 2013 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.lang.reflect.ParameterizedType;
12	+	import java.lang.reflect.Type;
13	+	import java.util.AbstractMap;
14	+	import java.util.Arrays;
15	+	import java.util.Collection;
16	+	import java.util.Comparator;
17	+	import java.util.Enumeration;
18	+	import java.util.HashMap;
19	+	import java.util.Hashtable;
20	+	import java.util.Iterator;
21	+	import java.util.Map;
22	+	import java.util.NoSuchElementException;
23	+	import java.util.Set;
24	+	import java.util.Spliterator;
25	+	import java.util.concurrent.ConcurrentMap;
26	+	import java.util.concurrent.ForkJoinPool;
27	+	import java.util.concurrent.atomic.AtomicReference;
28	+	import java.util.concurrent.locks.LockSupport;
29	+	import java.util.concurrent.locks.ReentrantLock;
30	+	import java.util.function.BiConsumer;
31	+	import java.util.function.BiFunction;
32	+	import java.util.function.BinaryOperator;
33	+	import java.util.function.Consumer;
34	+	import java.util.function.DoubleBinaryOperator;
35	+	import java.util.function.Function;
36	+	import java.util.function.IntBinaryOperator;
37	+	import java.util.function.LongBinaryOperator;
38	+	import java.util.function.ToDoubleBiFunction;
39	+	import java.util.function.ToDoubleFunction;
40	+	import java.util.function.ToIntBiFunction;
41	+	import java.util.function.ToIntFunction;
42	+	import java.util.function.ToLongBiFunction;
43	+	import java.util.function.ToLongFunction;
44	+	import java.util.stream.Stream;
45
46		/**
47		* A hash table supporting full concurrency of retrievals and
48	<	* adjustable expected concurrency for updates. This class obeys the
48	>	* high expected concurrency for updates. This class obeys the
49		* same functional specification as {@link java.util.Hashtable}, and
50		* includes versions of methods corresponding to each method of
51	<	* <tt>Hashtable</tt>. However, even though all operations are
51	>	* {@code Hashtable}. However, even though all operations are
52		* thread-safe, retrieval operations do <em>not</em> entail locking,
53		* and there is <em>not</em> any support for locking the entire table
54		* in a way that prevents all access.  This class is fully
55	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
55	>	* interoperable with {@code Hashtable} in programs that rely on its
56		* thread safety but not on its synchronization details.
57		*
58	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
59	<	* block, so may overlap with update operations (including
60	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
61	<	* of the most recently <em>completed</em> update operations holding
62	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
63	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
64	<	* removal of only some entries.  Similarly, Iterators and
65	<	* Enumerations return elements reflecting the state of the hash table
66	<	* at some point at or since the creation of the iterator/enumeration.
67	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
58	>	* <p>Retrieval operations (including {@code get}) generally do not
59	>	* block, so may overlap with update operations (including {@code put}
60	>	* and {@code remove}). Retrievals reflect the results of the most
61	>	* recently <em>completed</em> update operations holding upon their
62	>	* onset. (More formally, an update operation for a given key bears a
63	>	* <em>happens-before</em> relation with any (non-null) retrieval for
64	>	* that key reporting the updated value.)  For aggregate operations
65	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
66	>	* reflect insertion or removal of only some entries.  Similarly,
67	>	* Iterators, Spliterators and Enumerations return elements reflecting the
68	>	* state of the hash table at some point at or since the creation of the
69	>	* iterator/enumeration.  They do <em>not</em> throw {@link
70	>	* java.util.ConcurrentModificationException ConcurrentModificationException}.
71		* However, iterators are designed to be used by only one thread at a time.
72	+	* Bear in mind that the results of aggregate status methods including
73	+	* {@code size}, {@code isEmpty}, and {@code containsValue} are typically
74	+	* useful only when a map is not undergoing concurrent updates in other threads.
75	+	* Otherwise the results of these methods reflect transient states
76	+	* that may be adequate for monitoring or estimation purposes, but not
77	+	* for program control.
78	+	*
79	+	* <p>The table is dynamically expanded when there are too many
80	+	* collisions (i.e., keys that have distinct hash codes but fall into
81	+	* the same slot modulo the table size), with the expected average
82	+	* effect of maintaining roughly two bins per mapping (corresponding
83	+	* to a 0.75 load factor threshold for resizing). There may be much
84	+	* variance around this average as mappings are added and removed, but
85	+	* overall, this maintains a commonly accepted time/space tradeoff for
86	+	* hash tables.  However, resizing this or any other kind of hash
87	+	* table may be a relatively slow operation. When possible, it is a
88	+	* good idea to provide a size estimate as an optional {@code
89	+	* initialCapacity} constructor argument. An additional optional
90	+	* {@code loadFactor} constructor argument provides a further means of
91	+	* customizing initial table capacity by specifying the table density
92	+	* to be used in calculating the amount of space to allocate for the
93	+	* given number of elements.  Also, for compatibility with previous
94	+	* versions of this class, constructors may optionally specify an
95	+	* expected {@code concurrencyLevel} as an additional hint for
96	+	* internal sizing.  Note that using many keys with exactly the same
97	+	* {@code hashCode()} is a sure way to slow down performance of any
98	+	* hash table. To ameliorate impact, when keys are {@link Comparable},
99	+	* this class may use comparison order among keys to help break ties.
100	+	*
101	+	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
102	+	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
103	+	* (using {@link #keySet(Object)} when only keys are of interest, and the
104	+	* mapped values are (perhaps transiently) not used or all take the
105	+	* same mapping value.
106		*
107	<	* <p> The allowed concurrency among update operations is guided by
108	<	* the optional <tt>concurrencyLevel</tt> constructor argument
109	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
110	<	* table is internally partitioned to try to permit the indicated
111	<	* number of concurrent updates without contention. Because placement
112	<	* in hash tables is essentially random, the actual concurrency will
42	<	* vary.  Ideally, you should choose a value to accommodate as many
43	<	* threads as will ever concurrently modify the table. Using a
44	<	* significantly higher value than you need can waste space and time,
45	<	* and a significantly lower value can lead to thread contention. But
46	<	* overestimates and underestimates within an order of magnitude do
47	<	* not usually have much noticeable impact. A value of one is
48	<	* appropriate when it is known that only one thread will modify and
49	<	* all others will only read. Also, resizing this or any other kind of
50	<	* hash table is a relatively slow operation, so, when possible, it is
51	<	* a good idea to provide estimates of expected table sizes in
52	<	* constructors.
107	>	* <p>A ConcurrentHashMap can be used as scalable frequency map (a
108	>	* form of histogram or multiset) by using {@link
109	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
110	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
111	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
112	>	* {@code freqs.computeIfAbsent(k -> new LongAdder()).increment();}
113		*
114		* <p>This class and its views and iterators implement all of the
115		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
116		* interfaces.
117		*
118	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
119	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
118	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
119	>	* does <em>not</em> allow {@code null} to be used as a key or value.
120	>	*
121	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
122	>	* operations that, unlike most {@link Stream} methods, are designed
123	>	* to be safely, and often sensibly, applied even with maps that are
124	>	* being concurrently updated by other threads; for example, when
125	>	* computing a snapshot summary of the values in a shared registry.
126	>	* There are three kinds of operation, each with four forms, accepting
127	>	* functions with Keys, Values, Entries, and (Key, Value) arguments
128	>	* and/or return values. Because the elements of a ConcurrentHashMap
129	>	* are not ordered in any particular way, and may be processed in
130	>	* different orders in different parallel executions, the correctness
131	>	* of supplied functions should not depend on any ordering, or on any
132	>	* other objects or values that may transiently change while
133	>	* computation is in progress; and except for forEach actions, should
134	>	* ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry}
135	>	* objects do not support method {@code setValue}.
136	>	*
137	>	* <ul>
138	>	* <li> forEach: Perform a given action on each element.
139	>	* A variant form applies a given transformation on each element
140	>	* before performing the action.</li>
141	>	*
142	>	* <li> search: Return the first available non-null result of
143	>	* applying a given function on each element; skipping further
144	>	* search when a result is found.</li>
145	>	*
146	>	* <li> reduce: Accumulate each element.  The supplied reduction
147	>	* function cannot rely on ordering (more formally, it should be
148	>	* both associative and commutative).  There are five variants:
149	>	*
150	>	* <ul>
151	>	*
152	>	* <li> Plain reductions. (There is not a form of this method for
153	>	* (key, value) function arguments since there is no corresponding
154	>	* return type.)</li>
155	>	*
156	>	* <li> Mapped reductions that accumulate the results of a given
157	>	* function applied to each element.</li>
158	>	*
159	>	* <li> Reductions to scalar doubles, longs, and ints, using a
160	>	* given basis value.</li>
161	>	*
162	>	* </ul>
163	>	* </li>
164	>	* </ul>
165	>	*
166	>	* <p>These bulk operations accept a {@code parallelismThreshold}
167	>	* argument. Methods proceed sequentially if the current map size is
168	>	* estimated to be less than the given threshold. Using a value of
169	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
170	>	* of {@code 1} results in maximal parallelism by partitioning into
171	>	* enough subtasks to fully utilize the {@link
172	>	* ForkJoinPool#commonPool()} that is used for all parallel
173	>	* computations. Normally, you would initially choose one of these
174	>	* extreme values, and then measure performance of using in-between
175	>	* values that trade off overhead versus throughput.
176	>	*
177	>	* <p>The concurrency properties of bulk operations follow
178	>	* from those of ConcurrentHashMap: Any non-null result returned
179	>	* from {@code get(key)} and related access methods bears a
180	>	* happens-before relation with the associated insertion or
181	>	* update.  The result of any bulk operation reflects the
182	>	* composition of these per-element relations (but is not
183	>	* necessarily atomic with respect to the map as a whole unless it
184	>	* is somehow known to be quiescent).  Conversely, because keys
185	>	* and values in the map are never null, null serves as a reliable
186	>	* atomic indicator of the current lack of any result.  To
187	>	* maintain this property, null serves as an implicit basis for
188	>	* all non-scalar reduction operations. For the double, long, and
189	>	* int versions, the basis should be one that, when combined with
190	>	* any other value, returns that other value (more formally, it
191	>	* should be the identity element for the reduction). Most common
192	>	* reductions have these properties; for example, computing a sum
193	>	* with basis 0 or a minimum with basis MAX_VALUE.
194	>	*
195	>	* <p>Search and transformation functions provided as arguments
196	>	* should similarly return null to indicate the lack of any result
197	>	* (in which case it is not used). In the case of mapped
198	>	* reductions, this also enables transformations to serve as
199	>	* filters, returning null (or, in the case of primitive
200	>	* specializations, the identity basis) if the element should not
201	>	* be combined. You can create compound transformations and
202	>	* filterings by composing them yourself under this "null means
203	>	* there is nothing there now" rule before using them in search or
204	>	* reduce operations.
205	>	*
206	>	* <p>Methods accepting and/or returning Entry arguments maintain
207	>	* key-value associations. They may be useful for example when
208	>	* finding the key for the greatest value. Note that "plain" Entry
209	>	* arguments can be supplied using {@code new
210	>	* AbstractMap.SimpleEntry(k,v)}.
211	>	*
212	>	* <p>Bulk operations may complete abruptly, throwing an
213	>	* exception encountered in the application of a supplied
214	>	* function. Bear in mind when handling such exceptions that other
215	>	* concurrently executing functions could also have thrown
216	>	* exceptions, or would have done so if the first exception had
217	>	* not occurred.
218	>	*
219	>	* <p>Speedups for parallel compared to sequential forms are common
220	>	* but not guaranteed.  Parallel operations involving brief functions
221	>	* on small maps may execute more slowly than sequential forms if the
222	>	* underlying work to parallelize the computation is more expensive
223	>	* than the computation itself.  Similarly, parallelization may not
224	>	* lead to much actual parallelism if all processors are busy
225	>	* performing unrelated tasks.
226	>	*
227	>	* <p>All arguments to all task methods must be non-null.
228		*
229		* <p>This class is a member of the
230		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
#	Line 67 | Line 235 | import java.io.Serializable;
235		* @param <K> the type of keys maintained by this map
236		* @param <V> the type of mapped values
237		*/
238	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
239	<	implements ConcurrentMap<K, V>, Serializable {
238	>	public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
239	>	implements ConcurrentMap<K,V>, Serializable {
240		private static final long serialVersionUID = 7249069246763182397L;
241
242		/*
243	<	* The basic strategy is to subdivide the table among Segments,
244	<	* each of which itself is a concurrently readable hash table.  To
245	<	* reduce footprint, all but one segments are constructed only
246	<	* when first needed (see ensureSegment). To maintain visibility
247	<	* in the presence of lazy construction, accesses to segments as
248	<	* well as elements of segment's table must use volatile access,
249	<	* which is done via Unsafe within methods segmentAt etc
250	<	* below. These provide the functionality of AtomicReferenceArrays
251	<	* but reduce the levels of indirection. Additionally,
252	<	* volatile-writes of table elements and entry "next" fields
253	<	* within locked operations use the cheaper "lazySet" forms of
254	<	* writes (via putOrderedObject) because these writes are always
255	<	* followed by lock releases that maintain sequential consistency
256	<	* of table updates.
257	<	*
258	<	* Historical note: The previous version of this class relied
259	<	* heavily on "final" fields, which avoided some volatile reads at
260	<	* the expense of a large initial footprint.  Some remnants of
261	<	* that design (including forced construction of segment 0) exist
262	<	* to ensure serialization compatibility.
243	>	* Overview:
244	>	*
245	>	* The primary design goal of this hash table is to maintain
246	>	* concurrent readability (typically method get(), but also
247	>	* iterators and related methods) while minimizing update
248	>	* contention. Secondary goals are to keep space consumption about
249	>	* the same or better than java.util.HashMap, and to support high
250	>	* initial insertion rates on an empty table by many threads.
251	>	*
252	>	* This map usually acts as a binned (bucketed) hash table.  Each
253	>	* key-value mapping is held in a Node.  Most nodes are instances
254	>	* of the basic Node class with hash, key, value, and next
255	>	* fields. However, various subclasses exist: TreeNodes are
256	>	* arranged in balanced trees, not lists.  TreeBins hold the roots
257	>	* of sets of TreeNodes. ForwardingNodes are placed at the heads
258	>	* of bins during resizing. ReservationNodes are used as
259	>	* placeholders while establishing values in computeIfAbsent and
260	>	* related methods.  The types TreeBin, ForwardingNode, and
261	>	* ReservationNode do not hold normal user keys, values, or
262	>	* hashes, and are readily distinguishable during search etc
263	>	* because they have negative hash fields and null key and value
264	>	* fields. (These special nodes are either uncommon or transient,
265	>	* so the impact of carrying around some unused fields is
266	>	* insignificant.)
267	>	*
268	>	* The table is lazily initialized to a power-of-two size upon the
269	>	* first insertion.  Each bin in the table normally contains a
270	>	* list of Nodes (most often, the list has only zero or one Node).
271	>	* Table accesses require volatile/atomic reads, writes, and
272	>	* CASes.  Because there is no other way to arrange this without
273	>	* adding further indirections, we use intrinsics
274	>	* (sun.misc.Unsafe) operations.
275	>	*
276	>	* We use the top (sign) bit of Node hash fields for control
277	>	* purposes -- it is available anyway because of addressing
278	>	* constraints.  Nodes with negative hash fields are specially
279	>	* handled or ignored in map methods.
280	>	*
281	>	* Insertion (via put or its variants) of the first node in an
282	>	* empty bin is performed by just CASing it to the bin.  This is
283	>	* by far the most common case for put operations under most
284	>	* key/hash distributions.  Other update operations (insert,
285	>	* delete, and replace) require locks.  We do not want to waste
286	>	* the space required to associate a distinct lock object with
287	>	* each bin, so instead use the first node of a bin list itself as
288	>	* a lock. Locking support for these locks relies on builtin
289	>	* "synchronized" monitors.
290	>	*
291	>	* Using the first node of a list as a lock does not by itself
292	>	* suffice though: When a node is locked, any update must first
293	>	* validate that it is still the first node after locking it, and
294	>	* retry if not. Because new nodes are always appended to lists,
295	>	* once a node is first in a bin, it remains first until deleted
296	>	* or the bin becomes invalidated (upon resizing).
297	>	*
298	>	* The main disadvantage of per-bin locks is that other update
299	>	* operations on other nodes in a bin list protected by the same
300	>	* lock can stall, for example when user equals() or mapping
301	>	* functions take a long time.  However, statistically, under
302	>	* random hash codes, this is not a common problem.  Ideally, the
303	>	* frequency of nodes in bins follows a Poisson distribution
304	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
305	>	* parameter of about 0.5 on average, given the resizing threshold
306	>	* of 0.75, although with a large variance because of resizing
307	>	* granularity. Ignoring variance, the expected occurrences of
308	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
309	>	* first values are:
310	>	*
311	>	* 0:    0.60653066
312	>	* 1:    0.30326533
313	>	* 2:    0.07581633
314	>	* 3:    0.01263606
315	>	* 4:    0.00157952
316	>	* 5:    0.00015795
317	>	* 6:    0.00001316
318	>	* 7:    0.00000094
319	>	* 8:    0.00000006
320	>	* more: less than 1 in ten million
321	>	*
322	>	* Lock contention probability for two threads accessing distinct
323	>	* elements is roughly 1 / (8 * #elements) under random hashes.
324	>	*
325	>	* Actual hash code distributions encountered in practice
326	>	* sometimes deviate significantly from uniform randomness.  This
327	>	* includes the case when N > (1<<30), so some keys MUST collide.
328	>	* Similarly for dumb or hostile usages in which multiple keys are
329	>	* designed to have identical hash codes or ones that differs only
330	>	* in masked-out high bits. So we use a secondary strategy that
331	>	* applies when the number of nodes in a bin exceeds a
332	>	* threshold. These TreeBins use a balanced tree to hold nodes (a
333	>	* specialized form of red-black trees), bounding search time to
334	>	* O(log N).  Each search step in a TreeBin is at least twice as
335	>	* slow as in a regular list, but given that N cannot exceed
336	>	* (1<<64) (before running out of addresses) this bounds search
337	>	* steps, lock hold times, etc, to reasonable constants (roughly
338	>	* 100 nodes inspected per operation worst case) so long as keys
339	>	* are Comparable (which is very common -- String, Long, etc).
340	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
341	>	* traversal pointers as regular nodes, so can be traversed in
342	>	* iterators in the same way.
343	>	*
344	>	* The table is resized when occupancy exceeds a percentage
345	>	* threshold (nominally, 0.75, but see below).  Any thread
346	>	* noticing an overfull bin may assist in resizing after the
347	>	* initiating thread allocates and sets up the replacement array.
348	>	* However, rather than stalling, these other threads may proceed
349	>	* with insertions etc.  The use of TreeBins shields us from the
350	>	* worst case effects of overfilling while resizes are in
351	>	* progress.  Resizing proceeds by transferring bins, one by one,
352	>	* from the table to the next table. However, threads claim small
353	>	* blocks of indices to transfer (via field transferIndex) before
354	>	* doing so, reducing contention.  Because we are using
355	>	* power-of-two expansion, the elements from each bin must either
356	>	* stay at same index, or move with a power of two offset. We
357	>	* eliminate unnecessary node creation by catching cases where old
358	>	* nodes can be reused because their next fields won't change.  On
359	>	* average, only about one-sixth of them need cloning when a table
360	>	* doubles. The nodes they replace will be garbage collectable as
361	>	* soon as they are no longer referenced by any reader thread that
362	>	* may be in the midst of concurrently traversing table.  Upon
363	>	* transfer, the old table bin contains only a special forwarding
364	>	* node (with hash field "MOVED") that contains the next table as
365	>	* its key. On encountering a forwarding node, access and update
366	>	* operations restart, using the new table.
367	>	*
368	>	* Each bin transfer requires its bin lock, which can stall
369	>	* waiting for locks while resizing. However, because other
370	>	* threads can join in and help resize rather than contend for
371	>	* locks, average aggregate waits become shorter as resizing
372	>	* progresses.  The transfer operation must also ensure that all
373	>	* accessible bins in both the old and new table are usable by any
374	>	* traversal.  This is arranged in part by proceeding from the
375	>	* last bin (table.length - 1) up towards the first.  Upon seeing
376	>	* a forwarding node, traversals (see class Traverser) arrange to
377	>	* move to the new table without revisiting nodes.  To ensure that
378	>	* no intervening nodes are skipped even when moved out of order,
379	>	* a stack (see class TableStack) is created on first encounter of
380	>	* a forwarding node during a traversal, to maintain its place if
381	>	* later processing the current table. The need for these
382	>	* save/restore mechanics is relatively rare, but when one
383	>	* forwarding node is encountered, typically many more will be.
384	>	* So Traversers use a simple caching scheme to avoid creating so
385	>	* many new TableStack nodes. (Thanks to Peter Levart for
386	>	* suggesting use of a stack here.)
387	>	*
388	>	* The traversal scheme also applies to partial traversals of
389	>	* ranges of bins (via an alternate Traverser constructor)
390	>	* to support partitioned aggregate operations.  Also, read-only
391	>	* operations give up if ever forwarded to a null table, which
392	>	* provides support for shutdown-style clearing, which is also not
393	>	* currently implemented.
394	>	*
395	>	* Lazy table initialization minimizes footprint until first use,
396	>	* and also avoids resizings when the first operation is from a
397	>	* putAll, constructor with map argument, or deserialization.
398	>	* These cases attempt to override the initial capacity settings,
399	>	* but harmlessly fail to take effect in cases of races.
400	>	*
401	>	* The element count is maintained using a specialization of
402	>	* LongAdder. We need to incorporate a specialization rather than
403	>	* just use a LongAdder in order to access implicit
404	>	* contention-sensing that leads to creation of multiple
405	>	* CounterCells.  The counter mechanics avoid contention on
406	>	* updates but can encounter cache thrashing if read too
407	>	* frequently during concurrent access. To avoid reading so often,
408	>	* resizing under contention is attempted only upon adding to a
409	>	* bin already holding two or more nodes. Under uniform hash
410	>	* distributions, the probability of this occurring at threshold
411	>	* is around 13%, meaning that only about 1 in 8 puts check
412	>	* threshold (and after resizing, many fewer do so).
413	>	*
414	>	* TreeBins use a special form of comparison for search and
415	>	* related operations (which is the main reason we cannot use
416	>	* existing collections such as TreeMaps). TreeBins contain
417	>	* Comparable elements, but may contain others, as well as
418	>	* elements that are Comparable but not necessarily Comparable for
419	>	* the same T, so we cannot invoke compareTo among them. To handle
420	>	* this, the tree is ordered primarily by hash value, then by
421	>	* Comparable.compareTo order if applicable.  On lookup at a node,
422	>	* if elements are not comparable or compare as 0 then both left
423	>	* and right children may need to be searched in the case of tied
424	>	* hash values. (This corresponds to the full list search that
425	>	* would be necessary if all elements were non-Comparable and had
426	>	* tied hashes.) On insertion, to keep a total ordering (or as
427	>	* close as is required here) across rebalancings, we compare
428	>	* classes and identityHashCodes as tie-breakers. The red-black
429	>	* balancing code is updated from pre-jdk-collections
430	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
431	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
432	>	* Algorithms" (CLR).
433	>	*
434	>	* TreeBins also require an additional locking mechanism.  While
435	>	* list traversal is always possible by readers even during
436	>	* updates, tree traversal is not, mainly because of tree-rotations
437	>	* that may change the root node and/or its linkages.  TreeBins
438	>	* include a simple read-write lock mechanism parasitic on the
439	>	* main bin-synchronization strategy: Structural adjustments
440	>	* associated with an insertion or removal are already bin-locked
441	>	* (and so cannot conflict with other writers) but must wait for
442	>	* ongoing readers to finish. Since there can be only one such
443	>	* waiter, we use a simple scheme using a single "waiter" field to
444	>	* block writers.  However, readers need never block.  If the root
445	>	* lock is held, they proceed along the slow traversal path (via
446	>	* next-pointers) until the lock becomes available or the list is
447	>	* exhausted, whichever comes first. These cases are not fast, but
448	>	* maximize aggregate expected throughput.
449	>	*
450	>	* Maintaining API and serialization compatibility with previous
451	>	* versions of this class introduces several oddities. Mainly: We
452	>	* leave untouched but unused constructor arguments refering to
453	>	* concurrencyLevel. We accept a loadFactor constructor argument,
454	>	* but apply it only to initial table capacity (which is the only
455	>	* time that we can guarantee to honor it.) We also declare an
456	>	* unused "Segment" class that is instantiated in minimal form
457	>	* only when serializing.
458	>	*
459	>	* Also, solely for compatibility with previous versions of this
460	>	* class, it extends AbstractMap, even though all of its methods
461	>	* are overridden, so it is just useless baggage.
462	>	*
463	>	* This file is organized to make things a little easier to follow
464	>	* while reading than they might otherwise: First the main static
465	>	* declarations and utilities, then fields, then main public
466	>	* methods (with a few factorings of multiple public methods into
467	>	* internal ones), then sizing methods, trees, traversers, and
468	>	* bulk operations.
469		*/
470
471		/* ---------------- Constants -------------- */
472
473		/**
474	<	* The default initial capacity for this table,
475	<	* used when not otherwise specified in a constructor.
474	>	* The largest possible table capacity.  This value must be
475	>	* exactly 1<<30 to stay within Java array allocation and indexing
476	>	* bounds for power of two table sizes, and is further required
477	>	* because the top two bits of 32bit hash fields are used for
478	>	* control purposes.
479		*/
480	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
480	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
481
482		/**
483	<	* The default load factor for this table, used when not
484	<	* otherwise specified in a constructor.
483	>	* The default initial table capacity.  Must be a power of 2
484	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
485		*/
486	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
486	>	private static final int DEFAULT_CAPACITY = 16;
487
488		/**
489	<	* The default concurrency level for this table, used when not
490	<	* otherwise specified in a constructor.
489	>	* The largest possible (non-power of two) array size.
490	>	* Needed by toArray and related methods.
491		*/
492	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
492	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
493
494		/**
495	<	* The maximum capacity, used if a higher value is implicitly
496	<	* specified by either of the constructors with arguments.  MUST
120	<	* be a power of two <= 1<<30 to ensure that entries are indexable
121	<	* using ints.
495	>	* The default concurrency level for this table. Unused but
496	>	* defined for compatibility with previous versions of this class.
497		*/
498	<	static final int MAXIMUM_CAPACITY = 1 << 30;
498	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
499
500		/**
501	<	* The minimum capacity for per-segment tables.  Must be a power
502	<	* of two, at least two to avoid immediate resizing on next use
503	<	* after lazy construction.
501	>	* The load factor for this table. Overrides of this value in
502	>	* constructors affect only the initial table capacity.  The
503	>	* actual floating point value isn't normally used -- it is
504	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
505	>	* the associated resizing threshold.
506		*/
507	<	static final int MIN_SEGMENT_TABLE_CAPACITY = 2;
507	>	private static final float LOAD_FACTOR = 0.75f;
508
509		/**
510	<	* The maximum number of segments to allow; used to bound
511	<	* constructor arguments. Must be power of two less than 1 << 24.
510	>	* The bin count threshold for using a tree rather than list for a
511	>	* bin.  Bins are converted to trees when adding an element to a
512	>	* bin with at least this many nodes. The value must be greater
513	>	* than 2, and should be at least 8 to mesh with assumptions in
514	>	* tree removal about conversion back to plain bins upon
515	>	* shrinkage.
516		*/
517	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
517	>	static final int TREEIFY_THRESHOLD = 8;
518
519		/**
520	<	* Number of unsynchronized retries in size and containsValue
521	<	* methods before resorting to locking. This is used to avoid
522	<	* unbounded retries if tables undergo continuous modification
142	<	* which would make it impossible to obtain an accurate result.
520	>	* The bin count threshold for untreeifying a (split) bin during a
521	>	* resize operation. Should be less than TREEIFY_THRESHOLD, and at
522	>	* most 6 to mesh with shrinkage detection under removal.
523		*/
524	<	static final int RETRIES_BEFORE_LOCK = 2;
145	<
146	<	/* ---------------- Fields -------------- */
524	>	static final int UNTREEIFY_THRESHOLD = 6;
525
526		/**
527	<	* Mask value for indexing into segments. The upper bits of a
528	<	* key's hash code are used to choose the segment.
527	>	* The smallest table capacity for which bins may be treeified.
528	>	* (Otherwise the table is resized if too many nodes in a bin.)
529	>	* The value should be at least 4 * TREEIFY_THRESHOLD to avoid
530	>	* conflicts between resizing and treeification thresholds.
531		*/
532	<	final int segmentMask;
532	>	static final int MIN_TREEIFY_CAPACITY = 64;
533
534		/**
535	<	* Shift value for indexing within segments.
535	>	* Minimum number of rebinnings per transfer step. Ranges are
536	>	* subdivided to allow multiple resizer threads.  This value
537	>	* serves as a lower bound to avoid resizers encountering
538	>	* excessive memory contention.  The value should be at least
539	>	* DEFAULT_CAPACITY.
540		*/
541	<	final int segmentShift;
541	>	private static final int MIN_TRANSFER_STRIDE = 16;
542
543	<	/**
544	<	* The segments, each of which is a specialized hash table.
543	>	/*
544	>	* Encodings for Node hash fields. See above for explanation.
545		*/
546	<	final Segment<K,V>[] segments;
547	<
548	<	transient Set<K> keySet;
549	<	transient Set<Map.Entry<K,V>> entrySet;
550	<	transient Collection<V> values;
551	<
552	<	/**
553	<	* ConcurrentHashMap list entry. Note that this is never exported
554	<	* out as a user-visible Map.Entry.
546	>	static final int MOVED     = -1; // hash for forwarding nodes
547	>	static final int TREEBIN   = -2; // hash for roots of trees
548	>	static final int RESERVED  = -3; // hash for transient reservations
549	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
550	>
551	>	/** Number of CPUS, to place bounds on some sizings */
552	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
553	>
554	>	/** For serialization compatibility. */
555	>	private static final ObjectStreamField[] serialPersistentFields = {
556	>	new ObjectStreamField("segments", Segment[].class),
557	>	new ObjectStreamField("segmentMask", Integer.TYPE),
558	>	new ObjectStreamField("segmentShift", Integer.TYPE)
559	>	};
560	>
561	>	/* ---------------- Nodes -------------- */
562	>
563	>	/**
564	>	* Key-value entry.  This class is never exported out as a
565	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
566	>	* MapEntry below), but can be used for read-only traversals used
567	>	* in bulk tasks.  Subclasses of Node with a negative hash field
568	>	* are special, and contain null keys and values (but are never
569	>	* exported).  Otherwise, keys and vals are never null.
570		*/
571	<	static final class HashEntry<K,V> {
571	>	static class Node<K,V> implements Map.Entry<K,V> {
572		final int hash;
573		final K key;
574	<	volatile V value;
575	<	volatile HashEntry<K,V> next;
574	>	volatile V val;
575	>	volatile Node<K,V> next;
576
577	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
577	>	Node(int hash, K key, V val, Node<K,V> next) {
578		this.hash = hash;
579		this.key = key;
580	<	this.value = value;
580	>	this.val = val;
581		this.next = next;
582		}
583
584	+	public final K getKey()       { return key; }
585	+	public final V getValue()     { return val; }
586	+	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
587	+	public final String toString(){ return key + "=" + val; }
588	+	public final V setValue(V value) {
589	+	throw new UnsupportedOperationException();
590	+	}
591	+
592	+	public final boolean equals(Object o) {
593	+	Object k, v, u; Map.Entry<?,?> e;
594	+	return ((o instanceof Map.Entry) &&
595	+	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
596	+	(v = e.getValue()) != null &&
597	+	(k == key || k.equals(key)) &&
598	+	(v == (u = val) || v.equals(u)));
599	+	}
600	+
601		/**
602	<	* Sets next field with volatile write semantics.  (See above
187	<	* about use of putOrderedObject.)
602	>	* Virtualized support for map.get(); overridden in subclasses.
603		*/
604	<	final void setNext(HashEntry<K,V> n) {
605	<	UNSAFE.putOrderedObject(this, nextOffset, n);
604	>	Node<K,V> find(int h, Object k) {
605	>	Node<K,V> e = this;
606	>	if (k != null) {
607	>	do {
608	>	K ek;
609	>	if (e.hash == h &&
610	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
611	>	return e;
612	>	} while ((e = e.next) != null);
613	>	}
614	>	return null;
615		}
616	+	}
617
618	<	// Unsafe mechanics
619	<	static final sun.misc.Unsafe UNSAFE;
620	<	static final long nextOffset;
621	<	static {
622	<	try {
623	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
624	<	Class<?> k = HashEntry.class;
625	<	nextOffset = UNSAFE.objectFieldOffset
626	<	(k.getDeclaredField("next"));
627	<	} catch (Exception e) {
628	<	throw new Error(e);
618	>	/* ---------------- Static utilities -------------- */
619	>
620	>	/**
621	>	* Spreads (XORs) higher bits of hash to lower and also forces top
622	>	* bit to 0. Because the table uses power-of-two masking, sets of
623	>	* hashes that vary only in bits above the current mask will
624	>	* always collide. (Among known examples are sets of Float keys
625	>	* holding consecutive whole numbers in small tables.)  So we
626	>	* apply a transform that spreads the impact of higher bits
627	>	* downward. There is a tradeoff between speed, utility, and
628	>	* quality of bit-spreading. Because many common sets of hashes
629	>	* are already reasonably distributed (so don't benefit from
630	>	* spreading), and because we use trees to handle large sets of
631	>	* collisions in bins, we just XOR some shifted bits in the
632	>	* cheapest possible way to reduce systematic lossage, as well as
633	>	* to incorporate impact of the highest bits that would otherwise
634	>	* never be used in index calculations because of table bounds.
635	>	*/
636	>	static final int spread(int h) {
637	>	return (h ^ (h >>> 16)) & HASH_BITS;
638	>	}
639	>
640	>	/**
641	>	* Returns a power of two table size for the given desired capacity.
642	>	* See Hackers Delight, sec 3.2
643	>	*/
644	>	private static final int tableSizeFor(int c) {
645	>	int n = c - 1;
646	>	n |= n >>> 1;
647	>	n |= n >>> 2;
648	>	n |= n >>> 4;
649	>	n |= n >>> 8;
650	>	n |= n >>> 16;
651	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
652	>	}
653	>
654	>	/**
655	>	* Returns x's Class if it is of the form "class C implements
656	>	* Comparable<C>", else null.
657	>	*/
658	>	static Class<?> comparableClassFor(Object x) {
659	>	if (x instanceof Comparable) {
660	>	Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
661	>	if ((c = x.getClass()) == String.class) // bypass checks
662	>	return c;
663	>	if ((ts = c.getGenericInterfaces()) != null) {
664	>	for (int i = 0; i < ts.length; ++i) {
665	>	if (((t = ts[i]) instanceof ParameterizedType) &&
666	>	((p = (ParameterizedType)t).getRawType() ==
667	>	Comparable.class) &&
668	>	(as = p.getActualTypeArguments()) != null &&
669	>	as.length == 1 && as[0] == c) // type arg is c
670	>	return c;
671	>	}
672		}
673		}
674	+	return null;
675		}
676
677		/**
678	<	* Gets the ith element of given table (if nonnull) with volatile
679	<	* read semantics. Note: This is manually integrated into a few
680	<	* performance-sensitive methods to reduce call overhead.
678	>	* Returns k.compareTo(x) if x matches kc (k's screened comparable
679	>	* class), else 0.
680	>	*/
681	>	@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
682	>	static int compareComparables(Class<?> kc, Object k, Object x) {
683	>	return (x == null || x.getClass() != kc ? 0 :
684	>	((Comparable)k).compareTo(x));
685	>	}
686	>
687	>	/* ---------------- Table element access -------------- */
688	>
689	>	/*
690	>	* Volatile access methods are used for table elements as well as
691	>	* elements of in-progress next table while resizing.  All uses of
692	>	* the tab arguments must be null checked by callers.  All callers
693	>	* also paranoically precheck that tab's length is not zero (or an
694	>	* equivalent check), thus ensuring that any index argument taking
695	>	* the form of a hash value anded with (length - 1) is a valid
696	>	* index.  Note that, to be correct wrt arbitrary concurrency
697	>	* errors by users, these checks must operate on local variables,
698	>	* which accounts for some odd-looking inline assignments below.
699	>	* Note that calls to setTabAt always occur within locked regions,
700	>	* and so in principle require only release ordering, not need
701	>	* full volatile semantics, but are currently coded as volatile
702	>	* writes to be conservative.
703		*/
704	+
705		@SuppressWarnings("unchecked")
706	<	static final <K,V> HashEntry<K,V> entryAt(HashEntry<K,V>[] tab, int i) {
707	<	return (tab == null) ? null :
708	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
709	<	(tab, ((long)i << TSHIFT) + TBASE);
706	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
707	>	return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
708	>	}
709	>
710	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
711	>	Node<K,V> c, Node<K,V> v) {
712	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
713	>	}
714	>
715	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
716	>	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
717		}
718
719	+	/* ---------------- Fields -------------- */
720	+
721	+	/**
722	+	* The array of bins. Lazily initialized upon first insertion.
723	+	* Size is always a power of two. Accessed directly by iterators.
724	+	*/
725	+	transient volatile Node<K,V>[] table;
726	+
727		/**
728	<	* Sets the ith element of given table, with volatile write
222	<	* semantics. (See above about use of putOrderedObject.)
728	>	* The next table to use; non-null only while resizing.
729		*/
730	<	static final <K,V> void setEntryAt(HashEntry<K,V>[] tab, int i,
731	<	HashEntry<K,V> e) {
732	<	UNSAFE.putOrderedObject(tab, ((long)i << TSHIFT) + TBASE, e);
730	>	private transient volatile Node<K,V>[] nextTable;
731	>
732	>	/**
733	>	* Base counter value, used mainly when there is no contention,
734	>	* but also as a fallback during table initialization
735	>	* races. Updated via CAS.
736	>	*/
737	>	private transient volatile long baseCount;
738	>
739	>	/**
740	>	* Table initialization and resizing control.  When negative, the
741	>	* table is being initialized or resized: -1 for initialization,
742	>	* else -(1 + the number of active resizing threads).  Otherwise,
743	>	* when table is null, holds the initial table size to use upon
744	>	* creation, or 0 for default. After initialization, holds the
745	>	* next element count value upon which to resize the table.
746	>	*/
747	>	private transient volatile int sizeCtl;
748	>
749	>	/**
750	>	* The next table index (plus one) to split while resizing.
751	>	*/
752	>	private transient volatile int transferIndex;
753	>
754	>	/**
755	>	* Spinlock (locked via CAS) used when resizing and/or creating CounterCells.
756	>	*/
757	>	private transient volatile int cellsBusy;
758	>
759	>	/**
760	>	* Table of counter cells. When non-null, size is a power of 2.
761	>	*/
762	>	private transient volatile CounterCell[] counterCells;
763	>
764	>	// views
765	>	private transient KeySetView<K,V> keySet;
766	>	private transient ValuesView<K,V> values;
767	>	private transient EntrySetView<K,V> entrySet;
768	>
769	>
770	>	/* ---------------- Public operations -------------- */
771	>
772	>	/**
773	>	* Creates a new, empty map with the default initial table size (16).
774	>	*/
775	>	public ConcurrentHashMap() {
776		}
777
778		/**
779	<	* Applies a supplemental hash function to a given hashCode, which
780	<	* defends against poor quality hash functions.  This is critical
781	<	* because ConcurrentHashMap uses power-of-two length hash tables,
782	<	* that otherwise encounter collisions for hashCodes that do not
783	<	* differ in lower or upper bits.
779	>	* Creates a new, empty map with an initial table size
780	>	* accommodating the specified number of elements without the need
781	>	* to dynamically resize.
782	>	*
783	>	* @param initialCapacity The implementation performs internal
784	>	* sizing to accommodate this many elements.
785	>	* @throws IllegalArgumentException if the initial capacity of
786	>	* elements is negative
787		*/
788	<	private static int hash(int h) {
789	<	// Spread bits to regularize both segment and index locations,
790	<	// using variant of single-word Wang/Jenkins hash.
791	<	h += (h <<  15) ^ 0xffffcd7d;
792	<	h ^= (h >>> 10);
793	<	h += (h <<   3);
794	<	h ^= (h >>>  6);
243	<	h += (h <<   2) + (h << 14);
244	<	return h ^ (h >>> 16);
788	>	public ConcurrentHashMap(int initialCapacity) {
789	>	if (initialCapacity < 0)
790	>	throw new IllegalArgumentException();
791	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
792	>	MAXIMUM_CAPACITY :
793	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
794	>	this.sizeCtl = cap;
795		}
796
797		/**
798	<	* Segments are specialized versions of hash tables.  This
799	<	* subclasses from ReentrantLock opportunistically, just to
800	<	* simplify some locking and avoid separate construction.
798	>	* Creates a new map with the same mappings as the given map.
799	>	*
800	>	* @param m the map
801		*/
802	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
803	<	/*
804	<	* Segments maintain a table of entry lists that are always
805	<	* kept in a consistent state, so can be read (via volatile
256	<	* reads of segments and tables) without locking.  This
257	<	* requires replicating nodes when necessary during table
258	<	* resizing, so the old lists can be traversed by readers
259	<	* still using old version of table.
260	<	*
261	<	* This class defines only mutative methods requiring locking.
262	<	* Except as noted, the methods of this class perform the
263	<	* per-segment versions of ConcurrentHashMap methods.  (Other
264	<	* methods are integrated directly into ConcurrentHashMap
265	<	* methods.) These mutative methods use a form of controlled
266	<	* spinning on contention via methods scanAndLock and
267	<	* scanAndLockForPut. These intersperse tryLocks with
268	<	* traversals to locate nodes.  The main benefit is to absorb
269	<	* cache misses (which are very common for hash tables) while
270	<	* obtaining locks so that traversal is faster once
271	<	* acquired. We do not actually use the found nodes since they
272	<	* must be re-acquired under lock anyway to ensure sequential
273	<	* consistency of updates (and in any case may be undetectably
274	<	* stale), but they will normally be much faster to re-locate.
275	<	* Also, scanAndLockForPut speculatively creates a fresh node
276	<	* to use in put if no node is found.
277	<	*/
802	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
803	>	this.sizeCtl = DEFAULT_CAPACITY;
804	>	putAll(m);
805	>	}
806
807	<	private static final long serialVersionUID = 2249069246763182397L;
807	>	/**
808	>	* Creates a new, empty map with an initial table size based on
809	>	* the given number of elements ({@code initialCapacity}) and
810	>	* initial table density ({@code loadFactor}).
811	>	*
812	>	* @param initialCapacity the initial capacity. The implementation
813	>	* performs internal sizing to accommodate this many elements,
814	>	* given the specified load factor.
815	>	* @param loadFactor the load factor (table density) for
816	>	* establishing the initial table size
817	>	* @throws IllegalArgumentException if the initial capacity of
818	>	* elements is negative or the load factor is nonpositive
819	>	*
820	>	* @since 1.6
821	>	*/
822	>	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
823	>	this(initialCapacity, loadFactor, 1);
824	>	}
825
826	<	/**
827	<	* The maximum number of times to tryLock in a prescan before
828	<	* possibly blocking on acquire in preparation for a locked
829	<	* segment operation. On multiprocessors, using a bounded
830	<	* number of retries maintains cache acquired while locating
831	<	* nodes.
832	<	*/
833	<	static final int MAX_SCAN_RETRIES =
834	<	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
826	>	/**
827	>	* Creates a new, empty map with an initial table size based on
828	>	* the given number of elements ({@code initialCapacity}), table
829	>	* density ({@code loadFactor}), and number of concurrently
830	>	* updating threads ({@code concurrencyLevel}).
831	>	*
832	>	* @param initialCapacity the initial capacity. The implementation
833	>	* performs internal sizing to accommodate this many elements,
834	>	* given the specified load factor.
835	>	* @param loadFactor the load factor (table density) for
836	>	* establishing the initial table size
837	>	* @param concurrencyLevel the estimated number of concurrently
838	>	* updating threads. The implementation may use this value as
839	>	* a sizing hint.
840	>	* @throws IllegalArgumentException if the initial capacity is
841	>	* negative or the load factor or concurrencyLevel are
842	>	* nonpositive
843	>	*/
844	>	public ConcurrentHashMap(int initialCapacity,
845	>	float loadFactor, int concurrencyLevel) {
846	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
847	>	throw new IllegalArgumentException();
848	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
849	>	initialCapacity = concurrencyLevel;   // as estimated threads
850	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
851	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
852	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
853	>	this.sizeCtl = cap;
854	>	}
855
856	<	/**
292	<	* The per-segment table. Elements are accessed via
293	<	* entryAt/setEntryAt providing volatile semantics.
294	<	*/
295	<	transient volatile HashEntry<K,V>[] table;
856	>	// Original (since JDK1.2) Map methods
857
858	<	/**
859	<	* The number of elements. Accessed only either within locks
860	<	* or among other volatile reads that maintain visibility.
861	<	*/
862	<	transient int count;
858	>	/**
859	>	* {@inheritDoc}
860	>	*/
861	>	public int size() {
862	>	long n = sumCount();
863	>	return ((n < 0L) ? 0 :
864	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
865	>	(int)n);
866	>	}
867
868	<	/**
869	<	* The total number of mutative operations in this segment.
870	<	* Even though this may overflows 32 bits, it provides
871	<	* sufficient accuracy for stability checks in CHM isEmpty()
872	<	* and size() methods.  Accessed only either within locks or
873	<	* among other volatile reads that maintain visibility.
309	<	*/
310	<	transient int modCount;
868	>	/**
869	>	* {@inheritDoc}
870	>	*/
871	>	public boolean isEmpty() {
872	>	return sumCount() <= 0L; // ignore transient negative values
873	>	}
874
875	<	/**
876	<	* The table is rehashed when its size exceeds this threshold.
877	<	* (The value of this field is always <tt>(int)(capacity *
878	<	* loadFactor)</tt>.)
879	<	*/
880	<	transient int threshold;
875	>	/**
876	>	* Returns the value to which the specified key is mapped,
877	>	* or {@code null} if this map contains no mapping for the key.
878	>	*
879	>	* <p>More formally, if this map contains a mapping from a key
880	>	* {@code k} to a value {@code v} such that {@code key.equals(k)},
881	>	* then this method returns {@code v}; otherwise it returns
882	>	* {@code null}.  (There can be at most one such mapping.)
883	>	*
884	>	* @throws NullPointerException if the specified key is null
885	>	*/
886	>	public V get(Object key) {
887	>	Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
888	>	int h = spread(key.hashCode());
889	>	if ((tab = table) != null && (n = tab.length) > 0 &&
890	>	(e = tabAt(tab, (n - 1) & h)) != null) {
891	>	if ((eh = e.hash) == h) {
892	>	if ((ek = e.key) == key || (ek != null && key.equals(ek)))
893	>	return e.val;
894	>	}
895	>	else if (eh < 0)
896	>	return (p = e.find(h, key)) != null ? p.val : null;
897	>	while ((e = e.next) != null) {
898	>	if (e.hash == h &&
899	>	((ek = e.key) == key || (ek != null && key.equals(ek))))
900	>	return e.val;
901	>	}
902	>	}
903	>	return null;
904	>	}
905
906	<	/**
907	<	* The load factor for the hash table.  Even though this value
908	<	* is same for all segments, it is replicated to avoid needing
909	<	* links to outer object.
910	<	* @serial
911	<	*/
912	<	final float loadFactor;
906	>	/**
907	>	* Tests if the specified object is a key in this table.
908	>	*
909	>	* @param  key possible key
910	>	* @return {@code true} if and only if the specified object
911	>	*         is a key in this table, as determined by the
912	>	*         {@code equals} method; {@code false} otherwise
913	>	* @throws NullPointerException if the specified key is null
914	>	*/
915	>	public boolean containsKey(Object key) {
916	>	return get(key) != null;
917	>	}
918
919	<	Segment(float lf, int threshold, HashEntry<K,V>[] tab) {
920	<	this.loadFactor = lf;
921	<	this.threshold = threshold;
922	<	this.table = tab;
919	>	/**
920	>	* Returns {@code true} if this map maps one or more keys to the
921	>	* specified value. Note: This method may require a full traversal
922	>	* of the map, and is much slower than method {@code containsKey}.
923	>	*
924	>	* @param value value whose presence in this map is to be tested
925	>	* @return {@code true} if this map maps one or more keys to the
926	>	*         specified value
927	>	* @throws NullPointerException if the specified value is null
928	>	*/
929	>	public boolean containsValue(Object value) {
930	>	if (value == null)
931	>	throw new NullPointerException();
932	>	Node<K,V>[] t;
933	>	if ((t = table) != null) {
934	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
935	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
936	>	V v;
937	>	if ((v = p.val) == value || (v != null && value.equals(v)))
938	>	return true;
939	>	}
940		}
941	+	return false;
942	+	}
943
944	<	final V put(K key, int hash, V value, boolean onlyIfAbsent) {
945	<	HashEntry<K,V> node = tryLock() ? null :
946	<	scanAndLockForPut(key, hash, value);
947	<	V oldValue;
948	<	try {
949	<	HashEntry<K,V>[] tab = table;
950	<	int index = (tab.length - 1) & hash;
951	<	HashEntry<K,V> first = entryAt(tab, index);
952	<	for (HashEntry<K,V> e = first;;) {
953	<	if (e != null) {
954	<	K k;
955	<	if ((k = e.key) == key ||
956	<	(e.hash == hash && key.equals(k))) {
957	<	oldValue = e.value;
958	<	if (!onlyIfAbsent) {
959	<	e.value = value;
960	<	++modCount;
944	>	/**
945	>	* Maps the specified key to the specified value in this table.
946	>	* Neither the key nor the value can be null.
947	>	*
948	>	* <p>The value can be retrieved by calling the {@code get} method
949	>	* with a key that is equal to the original key.
950	>	*
951	>	* @param key key with which the specified value is to be associated
952	>	* @param value value to be associated with the specified key
953	>	* @return the previous value associated with {@code key}, or
954	>	*         {@code null} if there was no mapping for {@code key}
955	>	* @throws NullPointerException if the specified key or value is null
956	>	*/
957	>	public V put(K key, V value) {
958	>	return putVal(key, value, false);
959	>	}
960	>
961	>	/** Implementation for put and putIfAbsent */
962	>	final V putVal(K key, V value, boolean onlyIfAbsent) {
963	>	if (key == null || value == null) throw new NullPointerException();
964	>	int hash = spread(key.hashCode());
965	>	int binCount = 0;
966	>	for (Node<K,V>[] tab = table;;) {
967	>	Node<K,V> f; int n, i, fh;
968	>	if (tab == null || (n = tab.length) == 0)
969	>	tab = initTable();
970	>	else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
971	>	if (casTabAt(tab, i, null,
972	>	new Node<K,V>(hash, key, value, null)))
973	>	break;                   // no lock when adding to empty bin
974	>	}
975	>	else if ((fh = f.hash) == MOVED)
976	>	tab = helpTransfer(tab, f);
977	>	else {
978	>	V oldVal = null;
979	>	synchronized (f) {
980	>	if (tabAt(tab, i) == f) {
981	>	if (fh >= 0) {
982	>	binCount = 1;
983	>	for (Node<K,V> e = f;; ++binCount) {
984	>	K ek;
985	>	if (e.hash == hash &&
986	>	((ek = e.key) == key ||
987	>	(ek != null && key.equals(ek)))) {
988	>	oldVal = e.val;
989	>	if (!onlyIfAbsent)
990	>	e.val = value;
991	>	break;
992	>	}
993	>	Node<K,V> pred = e;
994	>	if ((e = e.next) == null) {
995	>	pred.next = new Node<K,V>(hash, key,
996	>	value, null);
997	>	break;
998	>	}
999	>	}
1000	>	}
1001	>	else if (f instanceof TreeBin) {
1002	>	Node<K,V> p;
1003	>	binCount = 2;
1004	>	if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
1005	>	value)) != null) {
1006	>	oldVal = p.val;
1007	>	if (!onlyIfAbsent)
1008	>	p.val = value;
1009		}
351	–	break;
1010		}
353	–	e = e.next;
354	–	}
355	–	else {
356	–	if (node != null)
357	–	node.setNext(first);
358	–	else
359	–	node = new HashEntry<K,V>(hash, key, value, first);
360	–	int c = count + 1;
361	–	if (c > threshold && tab.length < MAXIMUM_CAPACITY)
362	–	rehash(node);
363	–	else
364	–	setEntryAt(tab, index, node);
365	–	++modCount;
366	–	count = c;
367	–	oldValue = null;
368	–	break;
369	–	}
370	–	}
371	–	} finally {
372	–	unlock();
373	–	}
374	–	return oldValue;
375	–	}
376	–
377	–	/**
378	–	* Doubles size of table and repacks entries, also adding the
379	–	* given node to new table
380	–	*/
381	–	@SuppressWarnings("unchecked")
382	–	private void rehash(HashEntry<K,V> node) {
383	–	/*
384	–	* Reclassify nodes in each list to new table.  Because we
385	–	* are using power-of-two expansion, the elements from
386	–	* each bin must either stay at same index, or move with a
387	–	* power of two offset. We eliminate unnecessary node
388	–	* creation by catching cases where old nodes can be
389	–	* reused because their next fields won't change.
390	–	* Statistically, at the default threshold, only about
391	–	* one-sixth of them need cloning when a table
392	–	* doubles. The nodes they replace will be garbage
393	–	* collectable as soon as they are no longer referenced by
394	–	* any reader thread that may be in the midst of
395	–	* concurrently traversing table. Entry accesses use plain
396	–	* array indexing because they are followed by volatile
397	–	* table write.
398	–	*/
399	–	HashEntry<K,V>[] oldTable = table;
400	–	int oldCapacity = oldTable.length;
401	–	int newCapacity = oldCapacity << 1;
402	–	threshold = (int)(newCapacity * loadFactor);
403	–	HashEntry<K,V>[] newTable =
404	–	(HashEntry<K,V>[]) new HashEntry<?,?>[newCapacity];
405	–	int sizeMask = newCapacity - 1;
406	–	for (int i = 0; i < oldCapacity ; i++) {
407	–	HashEntry<K,V> e = oldTable[i];
408	–	if (e != null) {
409	–	HashEntry<K,V> next = e.next;
410	–	int idx = e.hash & sizeMask;
411	–	if (next == null)   //  Single node on list
412	–	newTable[idx] = e;
413	–	else { // Reuse consecutive sequence at same slot
414	–	HashEntry<K,V> lastRun = e;
415	–	int lastIdx = idx;
416	–	for (HashEntry<K,V> last = next;
417	–	last != null;
418	–	last = last.next) {
419	–	int k = last.hash & sizeMask;
420	–	if (k != lastIdx) {
421	–	lastIdx = k;
422	–	lastRun = last;
423	–	}
424	–	}
425	–	newTable[lastIdx] = lastRun;
426	–	// Clone remaining nodes
427	–	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
428	–	V v = p.value;
429	–	int h = p.hash;
430	–	int k = h & sizeMask;
431	–	HashEntry<K,V> n = newTable[k];
432	–	newTable[k] = new HashEntry<K,V>(h, p.key, v, n);
433	–	}
434	–	}
435	–	}
436	–	}
437	–	int nodeIndex = node.hash & sizeMask; // add the new node
438	–	node.setNext(newTable[nodeIndex]);
439	–	newTable[nodeIndex] = node;
440	–	table = newTable;
441	–	}
442	–
443	–	/**
444	–	* Scans for a node containing given key while trying to
445	–	* acquire lock, creating and returning one if not found. Upon
446	–	* return, guarantees that lock is held. Unlike in most
447	–	* methods, calls to method equals are not screened: Since
448	–	* traversal speed doesn't matter, we might as well help warm
449	–	* up the associated code and accesses as well.
450	–	*
451	–	* @return a new node if key not found, else null
452	–	*/
453	–	private HashEntry<K,V> scanAndLockForPut(K key, int hash, V value) {
454	–	HashEntry<K,V> first = entryForHash(this, hash);
455	–	HashEntry<K,V> e = first;
456	–	HashEntry<K,V> node = null;
457	–	int retries = -1; // negative while locating node
458	–	while (!tryLock()) {
459	–	HashEntry<K,V> f; // to recheck first below
460	–	if (retries < 0) {
461	–	if (e == null) {
462	–	if (node == null) // speculatively create node
463	–	node = new HashEntry<K,V>(hash, key, value, null);
464	–	retries = 0;
1011		}
466	–	else if (key.equals(e.key))
467	–	retries = 0;
468	–	else
469	–	e = e.next;
1012		}
1013	<	else if (++retries > MAX_SCAN_RETRIES) {
1014	<	lock();
1013	>	if (binCount != 0) {
1014	>	if (binCount >= TREEIFY_THRESHOLD)
1015	>	treeifyBin(tab, i);
1016	>	if (oldVal != null)
1017	>	return oldVal;
1018		break;
1019		}
475	–	else if ((retries & 1) == 0 &&
476	–	(f = entryForHash(this, hash)) != first) {
477	–	e = first = f; // re-traverse if entry changed
478	–	retries = -1;
479	–	}
480	–	}
481	–	return node;
482	–	}
483	–
484	–	/**
485	–	* Scans for a node containing the given key while trying to
486	–	* acquire lock for a remove or replace operation. Upon
487	–	* return, guarantees that lock is held.  Note that we must
488	–	* lock even if the key is not found, to ensure sequential
489	–	* consistency of updates.
490	–	*/
491	–	private void scanAndLock(Object key, int hash) {
492	–	// similar to but simpler than scanAndLockForPut
493	–	HashEntry<K,V> first = entryForHash(this, hash);
494	–	HashEntry<K,V> e = first;
495	–	int retries = -1;
496	–	while (!tryLock()) {
497	–	HashEntry<K,V> f;
498	–	if (retries < 0) {
499	–	if (e == null || key.equals(e.key))
500	–	retries = 0;
501	–	else
502	–	e = e.next;
503	–	}
504	–	else if (++retries > MAX_SCAN_RETRIES) {
505	–	lock();
506	–	break;
507	–	}
508	–	else if ((retries & 1) == 0 &&
509	–	(f = entryForHash(this, hash)) != first) {
510	–	e = first = f;
511	–	retries = -1;
512	–	}
1020		}
1021		}
1022	+	addCount(1L, binCount);
1023	+	return null;
1024	+	}
1025
1026	<	/**
1027	<	* Remove; match on key only if value null, else match both.
1028	<	*/
1029	<	final V remove(Object key, int hash, Object value) {
1030	<	if (!tryLock())
1031	<	scanAndLock(key, hash);
1032	<	V oldValue = null;
1033	<	try {
1034	<	HashEntry<K,V>[] tab = table;
1035	<	int index = (tab.length - 1) & hash;
1036	<	HashEntry<K,V> e = entryAt(tab, index);
1037	<	HashEntry<K,V> pred = null;
1038	<	while (e != null) {
1039	<	K k;
1040	<	HashEntry<K,V> next = e.next;
1041	<	if ((k = e.key) == key ||
1042	<	(e.hash == hash && key.equals(k))) {
1043	<	V v = e.value;
1044	<	if (value == null || value == v || value.equals(v)) {
1045	<	if (pred == null)
1046	<	setEntryAt(tab, index, next);
1047	<	else
1048	<	pred.setNext(next);
1049	<	++modCount;
1050	<	--count;
1051	<	oldValue = v;
1026	>	/**
1027	>	* Copies all of the mappings from the specified map to this one.
1028	>	* These mappings replace any mappings that this map had for any of the
1029	>	* keys currently in the specified map.
1030	>	*
1031	>	* @param m mappings to be stored in this map
1032	>	*/
1033	>	public void putAll(Map<? extends K, ? extends V> m) {
1034	>	tryPresize(m.size());
1035	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1036	>	putVal(e.getKey(), e.getValue(), false);
1037	>	}
1038	>
1039	>	/**
1040	>	* Removes the key (and its corresponding value) from this map.
1041	>	* This method does nothing if the key is not in the map.
1042	>	*
1043	>	* @param  key the key that needs to be removed
1044	>	* @return the previous value associated with {@code key}, or
1045	>	*         {@code null} if there was no mapping for {@code key}
1046	>	* @throws NullPointerException if the specified key is null
1047	>	*/
1048	>	public V remove(Object key) {
1049	>	return replaceNode(key, null, null);
1050	>	}
1051	>
1052	>	/**
1053	>	* Implementation for the four public remove/replace methods:
1054	>	* Replaces node value with v, conditional upon match of cv if
1055	>	* non-null.  If resulting value is null, delete.
1056	>	*/
1057	>	final V replaceNode(Object key, V value, Object cv) {
1058	>	int hash = spread(key.hashCode());
1059	>	for (Node<K,V>[] tab = table;;) {
1060	>	Node<K,V> f; int n, i, fh;
1061	>	if (tab == null || (n = tab.length) == 0 ||
1062	>	(f = tabAt(tab, i = (n - 1) & hash)) == null)
1063	>	break;
1064	>	else if ((fh = f.hash) == MOVED)
1065	>	tab = helpTransfer(tab, f);
1066	>	else {
1067	>	V oldVal = null;
1068	>	boolean validated = false;
1069	>	synchronized (f) {
1070	>	if (tabAt(tab, i) == f) {
1071	>	if (fh >= 0) {
1072	>	validated = true;
1073	>	for (Node<K,V> e = f, pred = null;;) {
1074	>	K ek;
1075	>	if (e.hash == hash &&
1076	>	((ek = e.key) == key ||
1077	>	(ek != null && key.equals(ek)))) {
1078	>	V ev = e.val;
1079	>	if (cv == null || cv == ev ||
1080	>	(ev != null && cv.equals(ev))) {
1081	>	oldVal = ev;
1082	>	if (value != null)
1083	>	e.val = value;
1084	>	else if (pred != null)
1085	>	pred.next = e.next;
1086	>	else
1087	>	setTabAt(tab, i, e.next);
1088	>	}
1089	>	break;
1090	>	}
1091	>	pred = e;
1092	>	if ((e = e.next) == null)
1093	>	break;
1094	>	}
1095	>	}
1096	>	else if (f instanceof TreeBin) {
1097	>	validated = true;
1098	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1099	>	TreeNode<K,V> r, p;
1100	>	if ((r = t.root) != null &&
1101	>	(p = r.findTreeNode(hash, key, null)) != null) {
1102	>	V pv = p.val;
1103	>	if (cv == null || cv == pv ||
1104	>	(pv != null && cv.equals(pv))) {
1105	>	oldVal = pv;
1106	>	if (value != null)
1107	>	p.val = value;
1108	>	else if (t.removeTreeNode(p))
1109	>	setTabAt(tab, i, untreeify(t.first));
1110	>	}
1111	>	}
1112		}
543	–	break;
1113		}
545	–	pred = e;
546	–	e = next;
1114		}
1115	<	} finally {
1116	<	unlock();
1117	<	}
1118	<	return oldValue;
1119	<	}
553	<
554	<	final boolean replace(K key, int hash, V oldValue, V newValue) {
555	<	if (!tryLock())
556	<	scanAndLock(key, hash);
557	<	boolean replaced = false;
558	<	try {
559	<	HashEntry<K,V> e;
560	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
561	<	K k;
562	<	if ((k = e.key) == key ||
563	<	(e.hash == hash && key.equals(k))) {
564	<	if (oldValue.equals(e.value)) {
565	<	e.value = newValue;
566	<	++modCount;
567	<	replaced = true;
568	<	}
569	<	break;
1115	>	if (validated) {
1116	>	if (oldVal != null) {
1117	>	if (value == null)
1118	>	addCount(-1L, -1);
1119	>	return oldVal;
1120		}
1121	+	break;
1122		}
572	–	} finally {
573	–	unlock();
1123		}
575	–	return replaced;
1124		}
1125	+	return null;
1126	+	}
1127
1128	<	final V replace(K key, int hash, V value) {
1129	<	if (!tryLock())
1130	<	scanAndLock(key, hash);
1131	<	V oldValue = null;
1132	<	try {
1133	<	HashEntry<K,V> e;
1134	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1135	<	K k;
1136	<	if ((k = e.key) == key ||
1137	<	(e.hash == hash && key.equals(k))) {
1138	<	oldValue = e.value;
1139	<	e.value = value;
1140	<	++modCount;
1141	<	break;
1128	>	/**
1129	>	* Removes all of the mappings from this map.
1130	>	*/
1131	>	public void clear() {
1132	>	long delta = 0L; // negative number of deletions
1133	>	int i = 0;
1134	>	Node<K,V>[] tab = table;
1135	>	while (tab != null && i < tab.length) {
1136	>	int fh;
1137	>	Node<K,V> f = tabAt(tab, i);
1138	>	if (f == null)
1139	>	++i;
1140	>	else if ((fh = f.hash) == MOVED) {
1141	>	tab = helpTransfer(tab, f);
1142	>	i = 0; // restart
1143	>	}
1144	>	else {
1145	>	synchronized (f) {
1146	>	if (tabAt(tab, i) == f) {
1147	>	Node<K,V> p = (fh >= 0 ? f :
1148	>	(f instanceof TreeBin) ?
1149	>	((TreeBin<K,V>)f).first : null);
1150	>	while (p != null) {
1151	>	--delta;
1152	>	p = p.next;
1153	>	}
1154	>	setTabAt(tab, i++, null);
1155		}
1156		}
594	–	} finally {
595	–	unlock();
1157		}
597	–	return oldValue;
1158		}
1159	+	if (delta != 0L)
1160	+	addCount(delta, -1);
1161	+	}
1162
1163	<	final void clear() {
1164	<	lock();
1165	<	try {
1166	<	HashEntry<K,V>[] tab = table;
1167	<	for (int i = 0; i < tab.length ; i++)
1168	<	setEntryAt(tab, i, null);
1169	<	++modCount;
1170	<	count = 0;
1171	<	} finally {
1172	<	unlock();
1173	<	}
1174	<	}
1163	>	/**
1164	>	* Returns a {@link Set} view of the keys contained in this map.
1165	>	* The set is backed by the map, so changes to the map are
1166	>	* reflected in the set, and vice-versa. The set supports element
1167	>	* removal, which removes the corresponding mapping from this map,
1168	>	* via the {@code Iterator.remove}, {@code Set.remove},
1169	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1170	>	* operations.  It does not support the {@code add} or
1171	>	* {@code addAll} operations.
1172	>	*
1173	>	* <p>The view's iterators and spliterators are
1174	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1175	>	*
1176	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1177	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1178	>	*
1179	>	* @return the set view
1180	>	*/
1181	>	public KeySetView<K,V> keySet() {
1182	>	KeySetView<K,V> ks;
1183	>	return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null));
1184	>	}
1185	>
1186	>	/**
1187	>	* Returns a {@link Collection} view of the values contained in this map.
1188	>	* The collection is backed by the map, so changes to the map are
1189	>	* reflected in the collection, and vice-versa.  The collection
1190	>	* supports element removal, which removes the corresponding
1191	>	* mapping from this map, via the {@code Iterator.remove},
1192	>	* {@code Collection.remove}, {@code removeAll},
1193	>	* {@code retainAll}, and {@code clear} operations.  It does not
1194	>	* support the {@code add} or {@code addAll} operations.
1195	>	*
1196	>	* <p>The view's iterators and spliterators are
1197	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1198	>	*
1199	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}
1200	>	* and {@link Spliterator#NONNULL}.
1201	>	*
1202	>	* @return the collection view
1203	>	*/
1204	>	public Collection<V> values() {
1205	>	ValuesView<K,V> vs;
1206	>	return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this));
1207		}
1208
1209	<	// Accessing segments
1209	>	/**
1210	>	* Returns a {@link Set} view of the mappings contained in this map.
1211	>	* The set is backed by the map, so changes to the map are
1212	>	* reflected in the set, and vice-versa.  The set supports element
1213	>	* removal, which removes the corresponding mapping from the map,
1214	>	* via the {@code Iterator.remove}, {@code Set.remove},
1215	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1216	>	* operations.
1217	>	*
1218	>	* <p>The view's iterators and spliterators are
1219	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
1220	>	*
1221	>	* <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT},
1222	>	* {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}.
1223	>	*
1224	>	* @return the set view
1225	>	*/
1226	>	public Set<Map.Entry<K,V>> entrySet() {
1227	>	EntrySetView<K,V> es;
1228	>	return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this));
1229	>	}
1230
1231		/**
1232	<	* Gets the jth element of given segment array (if nonnull) with
1233	<	* volatile element access semantics via Unsafe. (The null check
1234	<	* can trigger harmlessly only during deserialization.) Note:
1235	<	* because each element of segments array is set only once (using
1236	<	* fully ordered writes), some performance-sensitive methods rely
622	<	* on this method only as a recheck upon null reads.
1232	>	* Returns the hash code value for this {@link Map}, i.e.,
1233	>	* the sum of, for each key-value pair in the map,
1234	>	* {@code key.hashCode() ^ value.hashCode()}.
1235	>	*
1236	>	* @return the hash code value for this map
1237		*/
1238	<	@SuppressWarnings("unchecked")
1239	<	static final <K,V> Segment<K,V> segmentAt(Segment<K,V>[] ss, int j) {
1240	<	long u = (j << SSHIFT) + SBASE;
1241	<	return ss == null ? null :
1242	<	(Segment<K,V>) UNSAFE.getObjectVolatile(ss, u);
1238	>	public int hashCode() {
1239	>	int h = 0;
1240	>	Node<K,V>[] t;
1241	>	if ((t = table) != null) {
1242	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1243	>	for (Node<K,V> p; (p = it.advance()) != null; )
1244	>	h += p.key.hashCode() ^ p.val.hashCode();
1245	>	}
1246	>	return h;
1247		}
1248
1249		/**
1250	<	* Returns the segment for the given index, creating it and
1251	<	* recording in segment table (via CAS) if not already present.
1250	>	* Returns a string representation of this map.  The string
1251	>	* representation consists of a list of key-value mappings (in no
1252	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
1253	>	* mappings are separated by the characters {@code ", "} (comma
1254	>	* and space).  Each key-value mapping is rendered as the key
1255	>	* followed by an equals sign ("{@code =}") followed by the
1256	>	* associated value.
1257		*
1258	<	* @param k the index
636	<	* @return the segment
1258	>	* @return a string representation of this map
1259		*/
1260	<	@SuppressWarnings("unchecked")
1261	<	private Segment<K,V> ensureSegment(int k) {
1262	<	final Segment<K,V>[] ss = this.segments;
1263	<	long u = (k << SSHIFT) + SBASE; // raw offset
1264	<	Segment<K,V> seg;
1265	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u)) == null) {
1266	<	Segment<K,V> proto = ss[0]; // use segment 0 as prototype
1267	<	int cap = proto.table.length;
1268	<	float lf = proto.loadFactor;
1269	<	int threshold = (int)(cap * lf);
1270	<	HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry<?,?>[cap];
1271	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
1272	<	== null) { // recheck
1273	<	Segment<K,V> s = new Segment<K,V>(lf, threshold, tab);
1274	<	while ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
1275	<	== null) {
1276	<	if (UNSAFE.compareAndSwapObject(ss, u, null, seg = s))
655	<	break;
656	<	}
1260	>	public String toString() {
1261	>	Node<K,V>[] t;
1262	>	int f = (t = table) == null ? 0 : t.length;
1263	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1264	>	StringBuilder sb = new StringBuilder();
1265	>	sb.append('{');
1266	>	Node<K,V> p;
1267	>	if ((p = it.advance()) != null) {
1268	>	for (;;) {
1269	>	K k = p.key;
1270	>	V v = p.val;
1271	>	sb.append(k == this ? "(this Map)" : k);
1272	>	sb.append('=');
1273	>	sb.append(v == this ? "(this Map)" : v);
1274	>	if ((p = it.advance()) == null)
1275	>	break;
1276	>	sb.append(',').append(' ');
1277		}
1278		}
1279	<	return seg;
1279	>	return sb.append('}').toString();
1280		}
1281
662	–	// Hash-based segment and entry accesses
663	–
1282		/**
1283	<	* Gets the segment for the given hash code.
1283	>	* Compares the specified object with this map for equality.
1284	>	* Returns {@code true} if the given object is a map with the same
1285	>	* mappings as this map.  This operation may return misleading
1286	>	* results if either map is concurrently modified during execution
1287	>	* of this method.
1288	>	*
1289	>	* @param o object to be compared for equality with this map
1290	>	* @return {@code true} if the specified object is equal to this map
1291		*/
1292	<	@SuppressWarnings("unchecked")
1293	<	private Segment<K,V> segmentForHash(int h) {
1294	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
1295	<	return (Segment<K,V>) UNSAFE.getObjectVolatile(segments, u);
1292	>	public boolean equals(Object o) {
1293	>	if (o != this) {
1294	>	if (!(o instanceof Map))
1295	>	return false;
1296	>	Map<?,?> m = (Map<?,?>) o;
1297	>	Node<K,V>[] t;
1298	>	int f = (t = table) == null ? 0 : t.length;
1299	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
1300	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1301	>	V val = p.val;
1302	>	Object v = m.get(p.key);
1303	>	if (v == null || (v != val && !v.equals(val)))
1304	>	return false;
1305	>	}
1306	>	for (Map.Entry<?,?> e : m.entrySet()) {
1307	>	Object mk, mv, v;
1308	>	if ((mk = e.getKey()) == null ||
1309	>	(mv = e.getValue()) == null ||
1310	>	(v = get(mk)) == null ||
1311	>	(mv != v && !mv.equals(v)))
1312	>	return false;
1313	>	}
1314	>	}
1315	>	return true;
1316		}
1317
1318		/**
1319	<	* Gets the table entry for the given segment and hash code.
1319	>	* Stripped-down version of helper class used in previous version,
1320	>	* declared for the sake of serialization compatibility
1321		*/
1322	<	@SuppressWarnings("unchecked")
1323	<	static final <K,V> HashEntry<K,V> entryForHash(Segment<K,V> seg, int h) {
1324	<	HashEntry<K,V>[] tab;
1325	<	return (seg == null || (tab = seg.table) == null) ? null :
680	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
681	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
1322	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
1323	>	private static final long serialVersionUID = 2249069246763182397L;
1324	>	final float loadFactor;
1325	>	Segment(float lf) { this.loadFactor = lf; }
1326		}
1327
684	–	/* ---------------- Public operations -------------- */
685	–
1328		/**
1329	<	* Creates a new, empty map with the specified initial
1330	<	* capacity, load factor and concurrency level.
1331	<	*
1332	<	* @param initialCapacity the initial capacity. The implementation
1333	<	* performs internal sizing to accommodate this many elements.
1334	<	* @param loadFactor  the load factor threshold, used to control resizing.
1335	<	* Resizing may be performed when the average number of elements per
1336	<	* bin exceeds this threshold.
695	<	* @param concurrencyLevel the estimated number of concurrently
696	<	* updating threads. The implementation performs internal sizing
697	<	* to try to accommodate this many threads.
698	<	* @throws IllegalArgumentException if the initial capacity is
699	<	* negative or the load factor or concurrencyLevel are
700	<	* nonpositive.
1329	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
1330	>	* stream (i.e., serializes it).
1331	>	* @param s the stream
1332	>	* @throws java.io.IOException if an I/O error occurs
1333	>	* @serialData
1334	>	* the key (Object) and value (Object)
1335	>	* for each key-value mapping, followed by a null pair.
1336	>	* The key-value mappings are emitted in no particular order.
1337		*/
1338	<	@SuppressWarnings("unchecked")
1339	<	public ConcurrentHashMap(int initialCapacity,
1340	<	float loadFactor, int concurrencyLevel) {
1341	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
706	<	throw new IllegalArgumentException();
707	<	if (concurrencyLevel > MAX_SEGMENTS)
708	<	concurrencyLevel = MAX_SEGMENTS;
709	<	// Find power-of-two sizes best matching arguments
1338	>	private void writeObject(java.io.ObjectOutputStream s)
1339	>	throws java.io.IOException {
1340	>	// For serialization compatibility
1341	>	// Emulate segment calculation from previous version of this class
1342		int sshift = 0;
1343		int ssize = 1;
1344	<	while (ssize < concurrencyLevel) {
1344	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
1345		++sshift;
1346		ssize <<= 1;
1347		}
1348	<	this.segmentShift = 32 - sshift;
1349	<	this.segmentMask = ssize - 1;
1350	<	if (initialCapacity > MAXIMUM_CAPACITY)
1351	<	initialCapacity = MAXIMUM_CAPACITY;
1352	<	int c = initialCapacity / ssize;
1353	<	if (c * ssize < initialCapacity)
1354	<	++c;
1355	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
1356	<	while (cap < c)
1357	<	cap <<= 1;
1358	<	// create segments and segments[0]
1359	<	Segment<K,V> s0 =
1360	<	new Segment<K,V>(loadFactor, (int)(cap * loadFactor),
1361	<	(HashEntry<K,V>[])new HashEntry<?,?>[cap]);
1362	<	Segment<K,V>[] ss = (Segment<K,V>[])new Segment<?,?>[ssize];
1363	<	UNSAFE.putOrderedObject(ss, SBASE, s0); // ordered write of segments[0]
1364	<	this.segments = ss;
1348	>	int segmentShift = 32 - sshift;
1349	>	int segmentMask = ssize - 1;
1350	>	@SuppressWarnings("unchecked")
1351	>	Segment<K,V>[] segments = (Segment<K,V>[])
1352	>	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
1353	>	for (int i = 0; i < segments.length; ++i)
1354	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
1355	>	s.putFields().put("segments", segments);
1356	>	s.putFields().put("segmentShift", segmentShift);
1357	>	s.putFields().put("segmentMask", segmentMask);
1358	>	s.writeFields();
1359	>
1360	>	Node<K,V>[] t;
1361	>	if ((t = table) != null) {
1362	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1363	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1364	>	s.writeObject(p.key);
1365	>	s.writeObject(p.val);
1366	>	}
1367	>	}
1368	>	s.writeObject(null);
1369	>	s.writeObject(null);
1370	>	segments = null; // throw away
1371		}
1372
1373		/**
1374	<	* Creates a new, empty map with the specified initial capacity
1375	<	* and load factor and with the default concurrencyLevel (16).
1376	<	*
1377	<	* @param initialCapacity The implementation performs internal
1378	<	* sizing to accommodate this many elements.
1379	<	* @param loadFactor  the load factor threshold, used to control resizing.
1380	<	* Resizing may be performed when the average number of elements per
1381	<	* bin exceeds this threshold.
1382	<	* @throws IllegalArgumentException if the initial capacity of
1383	<	* elements is negative or the load factor is nonpositive
1374	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1375	>	* @param s the stream
1376	>	* @throws ClassNotFoundException if the class of a serialized object
1377	>	*         could not be found
1378	>	* @throws java.io.IOException if an I/O error occurs
1379	>	*/
1380	>	private void readObject(java.io.ObjectInputStream s)
1381	>	throws java.io.IOException, ClassNotFoundException {
1382	>	/*
1383	>	* To improve performance in typical cases, we create nodes
1384	>	* while reading, then place in table once size is known.
1385	>	* However, we must also validate uniqueness and deal with
1386	>	* overpopulated bins while doing so, which requires
1387	>	* specialized versions of putVal mechanics.
1388	>	*/
1389	>	sizeCtl = -1; // force exclusion for table construction
1390	>	s.defaultReadObject();
1391	>	long size = 0L;
1392	>	Node<K,V> p = null;
1393	>	for (;;) {
1394	>	@SuppressWarnings("unchecked")
1395	>	K k = (K) s.readObject();
1396	>	@SuppressWarnings("unchecked")
1397	>	V v = (V) s.readObject();
1398	>	if (k != null && v != null) {
1399	>	p = new Node<K,V>(spread(k.hashCode()), k, v, p);
1400	>	++size;
1401	>	}
1402	>	else
1403	>	break;
1404	>	}
1405	>	if (size == 0L)
1406	>	sizeCtl = 0;
1407	>	else {
1408	>	int n;
1409	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1410	>	n = MAXIMUM_CAPACITY;
1411	>	else {
1412	>	int sz = (int)size;
1413	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
1414	>	}
1415	>	@SuppressWarnings("unchecked")
1416	>	Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n];
1417	>	int mask = n - 1;
1418	>	long added = 0L;
1419	>	while (p != null) {
1420	>	boolean insertAtFront;
1421	>	Node<K,V> next = p.next, first;
1422	>	int h = p.hash, j = h & mask;
1423	>	if ((first = tabAt(tab, j)) == null)
1424	>	insertAtFront = true;
1425	>	else {
1426	>	K k = p.key;
1427	>	if (first.hash < 0) {
1428	>	TreeBin<K,V> t = (TreeBin<K,V>)first;
1429	>	if (t.putTreeVal(h, k, p.val) == null)
1430	>	++added;
1431	>	insertAtFront = false;
1432	>	}
1433	>	else {
1434	>	int binCount = 0;
1435	>	insertAtFront = true;
1436	>	Node<K,V> q; K qk;
1437	>	for (q = first; q != null; q = q.next) {
1438	>	if (q.hash == h &&
1439	>	((qk = q.key) == k ||
1440	>	(qk != null && k.equals(qk)))) {
1441	>	insertAtFront = false;
1442	>	break;
1443	>	}
1444	>	++binCount;
1445	>	}
1446	>	if (insertAtFront && binCount >= TREEIFY_THRESHOLD) {
1447	>	insertAtFront = false;
1448	>	++added;
1449	>	p.next = first;
1450	>	TreeNode<K,V> hd = null, tl = null;
1451	>	for (q = p; q != null; q = q.next) {
1452	>	TreeNode<K,V> t = new TreeNode<K,V>
1453	>	(q.hash, q.key, q.val, null, null);
1454	>	if ((t.prev = tl) == null)
1455	>	hd = t;
1456	>	else
1457	>	tl.next = t;
1458	>	tl = t;
1459	>	}
1460	>	setTabAt(tab, j, new TreeBin<K,V>(hd));
1461	>	}
1462	>	}
1463	>	}
1464	>	if (insertAtFront) {
1465	>	++added;
1466	>	p.next = first;
1467	>	setTabAt(tab, j, p);
1468	>	}
1469	>	p = next;
1470	>	}
1471	>	table = tab;
1472	>	sizeCtl = n - (n >>> 2);
1473	>	baseCount = added;
1474	>	}
1475	>	}
1476	>
1477	>	// ConcurrentMap methods
1478	>
1479	>	/**
1480	>	* {@inheritDoc}
1481		*
1482	<	* @since 1.6
1482	>	* @return the previous value associated with the specified key,
1483	>	*         or {@code null} if there was no mapping for the key
1484	>	* @throws NullPointerException if the specified key or value is null
1485		*/
1486	<	public ConcurrentHashMap(int initialCapacity, float loadFactor) {
1487	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
1486	>	public V putIfAbsent(K key, V value) {
1487	>	return putVal(key, value, true);
1488		}
1489
1490		/**
1491	<	* Creates a new, empty map with the specified initial capacity,
755	<	* and with default load factor (0.75) and concurrencyLevel (16).
1491	>	* {@inheritDoc}
1492		*
1493	<	* @param initialCapacity the initial capacity. The implementation
758	<	* performs internal sizing to accommodate this many elements.
759	<	* @throws IllegalArgumentException if the initial capacity of
760	<	* elements is negative.
1493	>	* @throws NullPointerException if the specified key is null
1494		*/
1495	<	public ConcurrentHashMap(int initialCapacity) {
1496	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1495	>	public boolean remove(Object key, Object value) {
1496	>	if (key == null)
1497	>	throw new NullPointerException();
1498	>	return value != null && replaceNode(key, null, value) != null;
1499		}
1500
1501		/**
1502	<	* Creates a new, empty map with a default initial capacity (16),
1503	<	* load factor (0.75) and concurrencyLevel (16).
1502	>	* {@inheritDoc}
1503	>	*
1504	>	* @throws NullPointerException if any of the arguments are null
1505		*/
1506	<	public ConcurrentHashMap() {
1507	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1506	>	public boolean replace(K key, V oldValue, V newValue) {
1507	>	if (key == null || oldValue == null || newValue == null)
1508	>	throw new NullPointerException();
1509	>	return replaceNode(key, newValue, oldValue) != null;
1510		}
1511
1512		/**
1513	<	* Creates a new map with the same mappings as the given map.
776	<	* The map is created with a capacity of 1.5 times the number
777	<	* of mappings in the given map or 16 (whichever is greater),
778	<	* and a default load factor (0.75) and concurrencyLevel (16).
1513	>	* {@inheritDoc}
1514		*
1515	<	* @param m the map
1515	>	* @return the previous value associated with the specified key,
1516	>	*         or {@code null} if there was no mapping for the key
1517	>	* @throws NullPointerException if the specified key or value is null
1518		*/
1519	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
1520	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
1521	<	DEFAULT_INITIAL_CAPACITY),
1522	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
786	<	putAll(m);
1519	>	public V replace(K key, V value) {
1520	>	if (key == null || value == null)
1521	>	throw new NullPointerException();
1522	>	return replaceNode(key, value, null);
1523		}
1524
1525	+	// Overrides of JDK8+ Map extension method defaults
1526	+
1527		/**
1528	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
1528	>	* Returns the value to which the specified key is mapped, or the
1529	>	* given default value if this map contains no mapping for the
1530	>	* key.
1531		*
1532	<	* @return <tt>true</tt> if this map contains no key-value mappings
1532	>	* @param key the key whose associated value is to be returned
1533	>	* @param defaultValue the value to return if this map contains
1534	>	* no mapping for the given key
1535	>	* @return the mapping for the key, if present; else the default value
1536	>	* @throws NullPointerException if the specified key is null
1537		*/
1538	<	public boolean isEmpty() {
1539	<	/*
1540	<	* Sum per-segment modCounts to avoid mis-reporting when
1541	<	* elements are concurrently added and removed in one segment
1542	<	* while checking another, in which case the table was never
1543	<	* actually empty at any point. (The sum ensures accuracy up
1544	<	* through at least 1<<31 per-segment modifications before
1545	<	* recheck.)  Methods size() and containsValue() use similar
1546	<	* constructions for stability checks.
1547	<	*/
1548	<	long sum = 0L;
1549	<	final Segment<K,V>[] segments = this.segments;
806	<	for (int j = 0; j < segments.length; ++j) {
807	<	Segment<K,V> seg = segmentAt(segments, j);
808	<	if (seg != null) {
809	<	if (seg.count != 0)
810	<	return false;
811	<	sum += seg.modCount;
1538	>	public V getOrDefault(Object key, V defaultValue) {
1539	>	V v;
1540	>	return (v = get(key)) == null ? defaultValue : v;
1541	>	}
1542	>
1543	>	public void forEach(BiConsumer<? super K, ? super V> action) {
1544	>	if (action == null) throw new NullPointerException();
1545	>	Node<K,V>[] t;
1546	>	if ((t = table) != null) {
1547	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1548	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1549	>	action.accept(p.key, p.val);
1550		}
1551		}
1552	<	if (sum != 0L) { // recheck unless no modifications
1553	<	for (int j = 0; j < segments.length; ++j) {
1554	<	Segment<K,V> seg = segmentAt(segments, j);
1555	<	if (seg != null) {
1556	<	if (seg.count != 0)
1557	<	return false;
1558	<	sum -= seg.modCount;
1552	>	}
1553	>
1554	>	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1555	>	if (function == null) throw new NullPointerException();
1556	>	Node<K,V>[] t;
1557	>	if ((t = table) != null) {
1558	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
1559	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
1560	>	V oldValue = p.val;
1561	>	for (K key = p.key;;) {
1562	>	V newValue = function.apply(key, oldValue);
1563	>	if (newValue == null)
1564	>	throw new NullPointerException();
1565	>	if (replaceNode(key, newValue, oldValue) != null ||
1566	>	(oldValue = get(key)) == null)
1567	>	break;
1568		}
1569		}
823	–	if (sum != 0L)
824	–	return false;
1570		}
826	–	return true;
1571		}
1572
1573		/**
1574	<	* Returns the number of key-value mappings in this map.  If the
1575	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
1576	<	* <tt>Integer.MAX_VALUE</tt>.
1574	>	* If the specified key is not already associated with a value,
1575	>	* attempts to compute its value using the given mapping function
1576	>	* and enters it into this map unless {@code null}.  The entire
1577	>	* method invocation is performed atomically, so the function is
1578	>	* applied at most once per key.  Some attempted update operations
1579	>	* on this map by other threads may be blocked while computation
1580	>	* is in progress, so the computation should be short and simple,
1581	>	* and must not attempt to update any other mappings of this map.
1582		*
1583	<	* @return the number of key-value mappings in this map
1583	>	* @param key key with which the specified value is to be associated
1584	>	* @param mappingFunction the function to compute a value
1585	>	* @return the current (existing or computed) value associated with
1586	>	*         the specified key, or null if the computed value is null
1587	>	* @throws NullPointerException if the specified key or mappingFunction
1588	>	*         is null
1589	>	* @throws IllegalStateException if the computation detectably
1590	>	*         attempts a recursive update to this map that would
1591	>	*         otherwise never complete
1592	>	* @throws RuntimeException or Error if the mappingFunction does so,
1593	>	*         in which case the mapping is left unestablished
1594		*/
1595	<	public int size() {
1596	<	// Try a few times to get accurate count. On failure due to
1597	<	// continuous async changes in table, resort to locking.
1598	<	final Segment<K,V>[] segments = this.segments;
1599	<	final int segmentCount = segments.length;
1600	<
1601	<	long previousSum = 0L;
1602	<	for (int retries = -1; retries < RETRIES_BEFORE_LOCK; retries++) {
1603	<	long sum = 0L;    // sum of modCounts
1604	<	long size = 0L;
1605	<	for (int i = 0; i < segmentCount; i++) {
1606	<	Segment<K,V> segment = segmentAt(segments, i);
1607	<	if (segment != null) {
1608	<	sum += segment.modCount;
1609	<	size += segment.count;
1610	<	}
1611	<	}
1612	<	if (sum == previousSum)
1613	<	return ((size >>> 31) == 0) ? (int) size : Integer.MAX_VALUE;
1614	<	previousSum = sum;
1595	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
1596	>	if (key == null || mappingFunction == null)
1597	>	throw new NullPointerException();
1598	>	int h = spread(key.hashCode());
1599	>	V val = null;
1600	>	int binCount = 0;
1601	>	for (Node<K,V>[] tab = table;;) {
1602	>	Node<K,V> f; int n, i, fh;
1603	>	if (tab == null || (n = tab.length) == 0)
1604	>	tab = initTable();
1605	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1606	>	Node<K,V> r = new ReservationNode<K,V>();
1607	>	synchronized (r) {
1608	>	if (casTabAt(tab, i, null, r)) {
1609	>	binCount = 1;
1610	>	Node<K,V> node = null;
1611	>	try {
1612	>	if ((val = mappingFunction.apply(key)) != null)
1613	>	node = new Node<K,V>(h, key, val, null);
1614	>	} finally {
1615	>	setTabAt(tab, i, node);
1616	>	}
1617	>	}
1618	>	}
1619	>	if (binCount != 0)
1620	>	break;
1621	>	}
1622	>	else if ((fh = f.hash) == MOVED)
1623	>	tab = helpTransfer(tab, f);
1624	>	else {
1625	>	boolean added = false;
1626	>	synchronized (f) {
1627	>	if (tabAt(tab, i) == f) {
1628	>	if (fh >= 0) {
1629	>	binCount = 1;
1630	>	for (Node<K,V> e = f;; ++binCount) {
1631	>	K ek; V ev;
1632	>	if (e.hash == h &&
1633	>	((ek = e.key) == key ||
1634	>	(ek != null && key.equals(ek)))) {
1635	>	val = e.val;
1636	>	break;
1637	>	}
1638	>	Node<K,V> pred = e;
1639	>	if ((e = e.next) == null) {
1640	>	if ((val = mappingFunction.apply(key)) != null) {
1641	>	added = true;
1642	>	pred.next = new Node<K,V>(h, key, val, null);
1643	>	}
1644	>	break;
1645	>	}
1646	>	}
1647	>	}
1648	>	else if (f instanceof TreeBin) {
1649	>	binCount = 2;
1650	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1651	>	TreeNode<K,V> r, p;
1652	>	if ((r = t.root) != null &&
1653	>	(p = r.findTreeNode(h, key, null)) != null)
1654	>	val = p.val;
1655	>	else if ((val = mappingFunction.apply(key)) != null) {
1656	>	added = true;
1657	>	t.putTreeVal(h, key, val);
1658	>	}
1659	>	}
1660	>	}
1661	>	}
1662	>	if (binCount != 0) {
1663	>	if (binCount >= TREEIFY_THRESHOLD)
1664	>	treeifyBin(tab, i);
1665	>	if (!added)
1666	>	return val;
1667	>	break;
1668	>	}
1669	>	}
1670		}
1671	<
1672	<	long size = 0L;
1673	<	for (int i = 0; i < segmentCount; i++) {
860	<	Segment<K,V> segment = ensureSegment(i);
861	<	segment.lock();
862	<	size += segment.count;
863	<	}
864	<	for (int i = 0; i < segmentCount; i++)
865	<	segments[i].unlock();
866	<	return ((size >>> 31) == 0) ? (int) size : Integer.MAX_VALUE;
1671	>	if (val != null)
1672	>	addCount(1L, binCount);
1673	>	return val;
1674		}
1675
1676		/**
1677	<	* Returns the value to which the specified key is mapped,
1678	<	* or {@code null} if this map contains no mapping for the key.
1677	>	* If the value for the specified key is present, attempts to
1678	>	* compute a new mapping given the key and its current mapped
1679	>	* value.  The entire method invocation is performed atomically.
1680	>	* Some attempted update operations on this map by other threads
1681	>	* may be blocked while computation is in progress, so the
1682	>	* computation should be short and simple, and must not attempt to
1683	>	* update any other mappings of this map.
1684		*
1685	<	* <p>More formally, if this map contains a mapping from a key
1686	<	* {@code k} to a value {@code v} such that {@code key.equals(k)},
1687	<	* then this method returns {@code v}; otherwise it returns
1688	<	* {@code null}.  (There can be at most one such mapping.)
1689	<	*
1690	<	* @throws NullPointerException if the specified key is null
1685	>	* @param key key with which a value may be associated
1686	>	* @param remappingFunction the function to compute a value
1687	>	* @return the new value associated with the specified key, or null if none
1688	>	* @throws NullPointerException if the specified key or remappingFunction
1689	>	*         is null
1690	>	* @throws IllegalStateException if the computation detectably
1691	>	*         attempts a recursive update to this map that would
1692	>	*         otherwise never complete
1693	>	* @throws RuntimeException or Error if the remappingFunction does so,
1694	>	*         in which case the mapping is unchanged
1695		*/
1696	<	@SuppressWarnings("unchecked")
1697	<	public V get(Object key) {
1698	<	Segment<K,V> s; // manually integrate access methods to reduce overhead
1699	<	HashEntry<K,V>[] tab;
1700	<	int h = hash(key.hashCode());
1701	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
1702	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
1703	<	(tab = s.table) != null) {
1704	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
1705	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
1706	<	e != null; e = e.next) {
1707	<	K k;
1708	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
1709	<	return e.value;
1696	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1697	>	if (key == null || remappingFunction == null)
1698	>	throw new NullPointerException();
1699	>	int h = spread(key.hashCode());
1700	>	V val = null;
1701	>	int delta = 0;
1702	>	int binCount = 0;
1703	>	for (Node<K,V>[] tab = table;;) {
1704	>	Node<K,V> f; int n, i, fh;
1705	>	if (tab == null || (n = tab.length) == 0)
1706	>	tab = initTable();
1707	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null)
1708	>	break;
1709	>	else if ((fh = f.hash) == MOVED)
1710	>	tab = helpTransfer(tab, f);
1711	>	else {
1712	>	synchronized (f) {
1713	>	if (tabAt(tab, i) == f) {
1714	>	if (fh >= 0) {
1715	>	binCount = 1;
1716	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1717	>	K ek;
1718	>	if (e.hash == h &&
1719	>	((ek = e.key) == key ||
1720	>	(ek != null && key.equals(ek)))) {
1721	>	val = remappingFunction.apply(key, e.val);
1722	>	if (val != null)
1723	>	e.val = val;
1724	>	else {
1725	>	delta = -1;
1726	>	Node<K,V> en = e.next;
1727	>	if (pred != null)
1728	>	pred.next = en;
1729	>	else
1730	>	setTabAt(tab, i, en);
1731	>	}
1732	>	break;
1733	>	}
1734	>	pred = e;
1735	>	if ((e = e.next) == null)
1736	>	break;
1737	>	}
1738	>	}
1739	>	else if (f instanceof TreeBin) {
1740	>	binCount = 2;
1741	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1742	>	TreeNode<K,V> r, p;
1743	>	if ((r = t.root) != null &&
1744	>	(p = r.findTreeNode(h, key, null)) != null) {
1745	>	val = remappingFunction.apply(key, p.val);
1746	>	if (val != null)
1747	>	p.val = val;
1748	>	else {
1749	>	delta = -1;
1750	>	if (t.removeTreeNode(p))
1751	>	setTabAt(tab, i, untreeify(t.first));
1752	>	}
1753	>	}
1754	>	}
1755	>	}
1756	>	}
1757	>	if (binCount != 0)
1758	>	break;
1759		}
1760		}
1761	<	return null;
1761	>	if (delta != 0)
1762	>	addCount((long)delta, binCount);
1763	>	return val;
1764		}
1765
1766		/**
1767	<	* Tests if the specified object is a key in this table.
1767	>	* Attempts to compute a mapping for the specified key and its
1768	>	* current mapped value (or {@code null} if there is no current
1769	>	* mapping). The entire method invocation is performed atomically.
1770	>	* Some attempted update operations on this map by other threads
1771	>	* may be blocked while computation is in progress, so the
1772	>	* computation should be short and simple, and must not attempt to
1773	>	* update any other mappings of this Map.
1774		*
1775	<	* @param  key   possible key
1776	<	* @return <tt>true</tt> if and only if the specified object
1777	<	*         is a key in this table, as determined by the
1778	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
1779	<	* @throws NullPointerException if the specified key is null
1780	<	*/
1781	<	@SuppressWarnings("unchecked")
1782	<	public boolean containsKey(Object key) {
1783	<	Segment<K,V> s; // same as get() except no need for volatile value read
1784	<	HashEntry<K,V>[] tab;
1785	<	int h = hash(key.hashCode());
1786	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
1787	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
1788	<	(tab = s.table) != null) {
1789	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
1790	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
1791	<	e != null; e = e.next) {
1792	<	K k;
1793	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
1794	<	return true;
1775	>	* @param key key with which the specified value is to be associated
1776	>	* @param remappingFunction the function to compute a value
1777	>	* @return the new value associated with the specified key, or null if none
1778	>	* @throws NullPointerException if the specified key or remappingFunction
1779	>	*         is null
1780	>	* @throws IllegalStateException if the computation detectably
1781	>	*         attempts a recursive update to this map that would
1782	>	*         otherwise never complete
1783	>	* @throws RuntimeException or Error if the remappingFunction does so,
1784	>	*         in which case the mapping is unchanged
1785	>	*/
1786	>	public V compute(K key,
1787	>	BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1788	>	if (key == null || remappingFunction == null)
1789	>	throw new NullPointerException();
1790	>	int h = spread(key.hashCode());
1791	>	V val = null;
1792	>	int delta = 0;
1793	>	int binCount = 0;
1794	>	for (Node<K,V>[] tab = table;;) {
1795	>	Node<K,V> f; int n, i, fh;
1796	>	if (tab == null || (n = tab.length) == 0)
1797	>	tab = initTable();
1798	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1799	>	Node<K,V> r = new ReservationNode<K,V>();
1800	>	synchronized (r) {
1801	>	if (casTabAt(tab, i, null, r)) {
1802	>	binCount = 1;
1803	>	Node<K,V> node = null;
1804	>	try {
1805	>	if ((val = remappingFunction.apply(key, null)) != null) {
1806	>	delta = 1;
1807	>	node = new Node<K,V>(h, key, val, null);
1808	>	}
1809	>	} finally {
1810	>	setTabAt(tab, i, node);
1811	>	}
1812	>	}
1813	>	}
1814	>	if (binCount != 0)
1815	>	break;
1816	>	}
1817	>	else if ((fh = f.hash) == MOVED)
1818	>	tab = helpTransfer(tab, f);
1819	>	else {
1820	>	synchronized (f) {
1821	>	if (tabAt(tab, i) == f) {
1822	>	if (fh >= 0) {
1823	>	binCount = 1;
1824	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1825	>	K ek;
1826	>	if (e.hash == h &&
1827	>	((ek = e.key) == key ||
1828	>	(ek != null && key.equals(ek)))) {
1829	>	val = remappingFunction.apply(key, e.val);
1830	>	if (val != null)
1831	>	e.val = val;
1832	>	else {
1833	>	delta = -1;
1834	>	Node<K,V> en = e.next;
1835	>	if (pred != null)
1836	>	pred.next = en;
1837	>	else
1838	>	setTabAt(tab, i, en);
1839	>	}
1840	>	break;
1841	>	}
1842	>	pred = e;
1843	>	if ((e = e.next) == null) {
1844	>	val = remappingFunction.apply(key, null);
1845	>	if (val != null) {
1846	>	delta = 1;
1847	>	pred.next =
1848	>	new Node<K,V>(h, key, val, null);
1849	>	}
1850	>	break;
1851	>	}
1852	>	}
1853	>	}
1854	>	else if (f instanceof TreeBin) {
1855	>	binCount = 1;
1856	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1857	>	TreeNode<K,V> r, p;
1858	>	if ((r = t.root) != null)
1859	>	p = r.findTreeNode(h, key, null);
1860	>	else
1861	>	p = null;
1862	>	V pv = (p == null) ? null : p.val;
1863	>	val = remappingFunction.apply(key, pv);
1864	>	if (val != null) {
1865	>	if (p != null)
1866	>	p.val = val;
1867	>	else {
1868	>	delta = 1;
1869	>	t.putTreeVal(h, key, val);
1870	>	}
1871	>	}
1872	>	else if (p != null) {
1873	>	delta = -1;
1874	>	if (t.removeTreeNode(p))
1875	>	setTabAt(tab, i, untreeify(t.first));
1876	>	}
1877	>	}
1878	>	}
1879	>	}
1880	>	if (binCount != 0) {
1881	>	if (binCount >= TREEIFY_THRESHOLD)
1882	>	treeifyBin(tab, i);
1883	>	break;
1884	>	}
1885		}
1886		}
1887	<	return false;
1887	>	if (delta != 0)
1888	>	addCount((long)delta, binCount);
1889	>	return val;
1890		}
1891
1892		/**
1893	<	* Returns <tt>true</tt> if this map maps one or more keys to the
1894	<	* specified value. Note: This method requires a full internal
1895	<	* traversal of the hash table, and so is much slower than
1896	<	* method <tt>containsKey</tt>.
1893	>	* If the specified key is not already associated with a
1894	>	* (non-null) value, associates it with the given value.
1895	>	* Otherwise, replaces the value with the results of the given
1896	>	* remapping function, or removes if {@code null}. The entire
1897	>	* method invocation is performed atomically.  Some attempted
1898	>	* update operations on this map by other threads may be blocked
1899	>	* while computation is in progress, so the computation should be
1900	>	* short and simple, and must not attempt to update any other
1901	>	* mappings of this Map.
1902		*
1903	<	* @param value value whose presence in this map is to be tested
1904	<	* @return <tt>true</tt> if this map maps one or more keys to the
1905	<	*         specified value
1906	<	* @throws NullPointerException if the specified value is null
1903	>	* @param key key with which the specified value is to be associated
1904	>	* @param value the value to use if absent
1905	>	* @param remappingFunction the function to recompute a value if present
1906	>	* @return the new value associated with the specified key, or null if none
1907	>	* @throws NullPointerException if the specified key or the
1908	>	*         remappingFunction is null
1909	>	* @throws RuntimeException or Error if the remappingFunction does so,
1910	>	*         in which case the mapping is unchanged
1911		*/
1912	<	public boolean containsValue(Object value) {
1913	<	// Same idea as size()
940	<	if (value == null)
1912	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1913	>	if (key == null || value == null || remappingFunction == null)
1914		throw new NullPointerException();
1915	<	final Segment<K,V>[] segments = this.segments;
1916	<	long previousSum = 0L;
1917	<	int lockCount = 0;
1918	<	try {
1919	<	for (int retries = -1; ; retries++) {
1920	<	long sum = 0L;    // sum of modCounts
1921	<	for (int j = 0; j < segments.length; j++) {
1922	<	Segment<K,V> segment;
1923	<	if (retries == RETRIES_BEFORE_LOCK) {
1924	<	segment = ensureSegment(j);
1925	<	segment.lock();
1926	<	lockCount++;
1927	<	} else {
1928	<	segment = segmentAt(segments, j);
1929	<	if (segment == null)
1930	<	continue;
1931	<	}
1932	<	HashEntry<K,V>[] tab = segment.table;
1933	<	if (tab != null) {
1934	<	for (int i = 0 ; i < tab.length; i++) {
1935	<	HashEntry<K,V> e;
1936	<	for (e = entryAt(tab, i); e != null; e = e.next) {
1937	<	V v = e.value;
1938	<	if (v != null && value.equals(v))
1939	<	return true;
1915	>	int h = spread(key.hashCode());
1916	>	V val = null;
1917	>	int delta = 0;
1918	>	int binCount = 0;
1919	>	for (Node<K,V>[] tab = table;;) {
1920	>	Node<K,V> f; int n, i, fh;
1921	>	if (tab == null || (n = tab.length) == 0)
1922	>	tab = initTable();
1923	>	else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
1924	>	if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) {
1925	>	delta = 1;
1926	>	val = value;
1927	>	break;
1928	>	}
1929	>	}
1930	>	else if ((fh = f.hash) == MOVED)
1931	>	tab = helpTransfer(tab, f);
1932	>	else {
1933	>	synchronized (f) {
1934	>	if (tabAt(tab, i) == f) {
1935	>	if (fh >= 0) {
1936	>	binCount = 1;
1937	>	for (Node<K,V> e = f, pred = null;; ++binCount) {
1938	>	K ek;
1939	>	if (e.hash == h &&
1940	>	((ek = e.key) == key ||
1941	>	(ek != null && key.equals(ek)))) {
1942	>	val = remappingFunction.apply(e.val, value);
1943	>	if (val != null)
1944	>	e.val = val;
1945	>	else {
1946	>	delta = -1;
1947	>	Node<K,V> en = e.next;
1948	>	if (pred != null)
1949	>	pred.next = en;
1950	>	else
1951	>	setTabAt(tab, i, en);
1952	>	}
1953	>	break;
1954	>	}
1955	>	pred = e;
1956	>	if ((e = e.next) == null) {
1957	>	delta = 1;
1958	>	val = value;
1959	>	pred.next =
1960	>	new Node<K,V>(h, key, val, null);
1961	>	break;
1962	>	}
1963	>	}
1964	>	}
1965	>	else if (f instanceof TreeBin) {
1966	>	binCount = 2;
1967	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
1968	>	TreeNode<K,V> r = t.root;
1969	>	TreeNode<K,V> p = (r == null) ? null :
1970	>	r.findTreeNode(h, key, null);
1971	>	val = (p == null) ? value :
1972	>	remappingFunction.apply(p.val, value);
1973	>	if (val != null) {
1974	>	if (p != null)
1975	>	p.val = val;
1976	>	else {
1977	>	delta = 1;
1978	>	t.putTreeVal(h, key, val);
1979	>	}
1980	>	}
1981	>	else if (p != null) {
1982	>	delta = -1;
1983	>	if (t.removeTreeNode(p))
1984	>	setTabAt(tab, i, untreeify(t.first));
1985		}
1986		}
969	–	sum += segment.modCount;
1987		}
1988		}
1989	<	if ((retries >= 0 && sum == previousSum) || lockCount > 0)
1990	<	return false;
1991	<	previousSum = sum;
1989	>	if (binCount != 0) {
1990	>	if (binCount >= TREEIFY_THRESHOLD)
1991	>	treeifyBin(tab, i);
1992	>	break;
1993	>	}
1994		}
976	–	} finally {
977	–	for (int j = 0; j < lockCount; j++)
978	–	segments[j].unlock();
1995		}
1996	+	if (delta != 0)
1997	+	addCount((long)delta, binCount);
1998	+	return val;
1999		}
2000
2001	+	// Hashtable legacy methods
2002	+
2003		/**
2004		* Legacy method testing if some key maps into the specified value
2005	<	* in this table.  This method is identical in functionality to
2006	<	* {@link #containsValue}, and exists solely to ensure
2005	>	* in this table.
2006	>	*
2007	>	* @deprecated This method is identical in functionality to
2008	>	* {@link #containsValue(Object)}, and exists solely to ensure
2009		* full compatibility with class {@link java.util.Hashtable},
2010		* which supported this method prior to introduction of the
2011		* Java Collections framework.
2012		*
2013		* @param  value a value to search for
2014	<	* @return <tt>true</tt> if and only if some key maps to the
2015	<	*         <tt>value</tt> argument in this table as
2016	<	*         determined by the <tt>equals</tt> method;
2017	<	*         <tt>false</tt> otherwise
2014	>	* @return {@code true} if and only if some key maps to the
2015	>	*         {@code value} argument in this table as
2016	>	*         determined by the {@code equals} method;
2017	>	*         {@code false} otherwise
2018		* @throws NullPointerException if the specified value is null
2019		*/
2020	+	@Deprecated
2021		public boolean contains(Object value) {
2022		return containsValue(value);
2023		}
2024
2025		/**
2026	<	* Maps the specified key to the specified value in this table.
1003	<	* Neither the key nor the value can be null.
1004	<	*
1005	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
1006	<	* with a key that is equal to the original key.
2026	>	* Returns an enumeration of the keys in this table.
2027		*
2028	<	* @param key key with which the specified value is to be associated
2029	<	* @param value value to be associated with the specified key
1010	<	* @return the previous value associated with <tt>key</tt>, or
1011	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
1012	<	* @throws NullPointerException if the specified key or value is null
2028	>	* @return an enumeration of the keys in this table
2029	>	* @see #keySet()
2030		*/
2031	<	@SuppressWarnings("unchecked")
2032	<	public V put(K key, V value) {
2033	<	Segment<K,V> s;
2034	<	if (value == null)
1018	<	throw new NullPointerException();
1019	<	int hash = hash(key.hashCode());
1020	<	int j = (hash >>> segmentShift) & segmentMask;
1021	<	if ((s = (Segment<K,V>)UNSAFE.getObject          // nonvolatile; recheck
1022	<	(segments, (j << SSHIFT) + SBASE)) == null) //  in ensureSegment
1023	<	s = ensureSegment(j);
1024	<	return s.put(key, hash, value, false);
2031	>	public Enumeration<K> keys() {
2032	>	Node<K,V>[] t;
2033	>	int f = (t = table) == null ? 0 : t.length;
2034	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2035		}
2036
2037		/**
2038	<	* {@inheritDoc}
2038	>	* Returns an enumeration of the values in this table.
2039		*
2040	<	* @return the previous value associated with the specified key,
2041	<	*         or <tt>null</tt> if there was no mapping for the key
1032	<	* @throws NullPointerException if the specified key or value is null
2040	>	* @return an enumeration of the values in this table
2041	>	* @see #values()
2042		*/
2043	<	@SuppressWarnings("unchecked")
2044	<	public V putIfAbsent(K key, V value) {
2045	<	Segment<K,V> s;
2046	<	if (value == null)
1038	<	throw new NullPointerException();
1039	<	int hash = hash(key.hashCode());
1040	<	int j = (hash >>> segmentShift) & segmentMask;
1041	<	if ((s = (Segment<K,V>)UNSAFE.getObject
1042	<	(segments, (j << SSHIFT) + SBASE)) == null)
1043	<	s = ensureSegment(j);
1044	<	return s.put(key, hash, value, true);
2043	>	public Enumeration<V> elements() {
2044	>	Node<K,V>[] t;
2045	>	int f = (t = table) == null ? 0 : t.length;
2046	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2047		}
2048
2049	+	// ConcurrentHashMap-only methods
2050	+
2051		/**
2052	<	* Copies all of the mappings from the specified map to this one.
2053	<	* These mappings replace any mappings that this map had for any of the
2054	<	* keys currently in the specified map.
2052	>	* Returns the number of mappings. This method should be used
2053	>	* instead of {@link #size} because a ConcurrentHashMap may
2054	>	* contain more mappings than can be represented as an int. The
2055	>	* value returned is an estimate; the actual count may differ if
2056	>	* there are concurrent insertions or removals.
2057		*
2058	<	* @param m mappings to be stored in this map
2058	>	* @return the number of mappings
2059	>	* @since 1.8
2060		*/
2061	<	public void putAll(Map<? extends K, ? extends V> m) {
2062	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
2063	<	put(e.getKey(), e.getValue());
2061	>	public long mappingCount() {
2062	>	long n = sumCount();
2063	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2064		}
2065
2066		/**
2067	<	* Removes the key (and its corresponding value) from this map.
2068	<	* This method does nothing if the key is not in the map.
2067	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2068	>	* from the given type to {@code Boolean.TRUE}.
2069		*
2070	<	* @param  key the key that needs to be removed
2071	<	* @return the previous value associated with <tt>key</tt>, or
2072	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
1066	<	* @throws NullPointerException if the specified key is null
2070	>	* @param <K> the element type of the returned set
2071	>	* @return the new set
2072	>	* @since 1.8
2073		*/
2074	<	public V remove(Object key) {
2075	<	int hash = hash(key.hashCode());
2076	<	Segment<K,V> s = segmentForHash(hash);
1071	<	return s == null ? null : s.remove(key, hash, null);
2074	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2075	>	return new KeySetView<K,Boolean>
2076	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2077		}
2078
2079		/**
2080	<	* {@inheritDoc}
2080	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2081	>	* from the given type to {@code Boolean.TRUE}.
2082		*
2083	<	* @throws NullPointerException if the specified key is null
2083	>	* @param initialCapacity The implementation performs internal
2084	>	* sizing to accommodate this many elements.
2085	>	* @param <K> the element type of the returned set
2086	>	* @return the new set
2087	>	* @throws IllegalArgumentException if the initial capacity of
2088	>	* elements is negative
2089	>	* @since 1.8
2090		*/
2091	<	public boolean remove(Object key, Object value) {
2092	<	int hash = hash(key.hashCode());
2093	<	Segment<K,V> s;
1082	<	return value != null && (s = segmentForHash(hash)) != null &&
1083	<	s.remove(key, hash, value) != null;
2091	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2092	>	return new KeySetView<K,Boolean>
2093	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2094		}
2095
2096		/**
2097	<	* {@inheritDoc}
2097	>	* Returns a {@link Set} view of the keys in this map, using the
2098	>	* given common mapped value for any additions (i.e., {@link
2099	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2100	>	* This is of course only appropriate if it is acceptable to use
2101	>	* the same value for all additions from this view.
2102		*
2103	<	* @throws NullPointerException if any of the arguments are null
2103	>	* @param mappedValue the mapped value to use for any additions
2104	>	* @return the set view
2105	>	* @throws NullPointerException if the mappedValue is null
2106		*/
2107	<	public boolean replace(K key, V oldValue, V newValue) {
2108	<	int hash = hash(key.hashCode());
1093	<	if (oldValue == null || newValue == null)
2107	>	public KeySetView<K,V> keySet(V mappedValue) {
2108	>	if (mappedValue == null)
2109		throw new NullPointerException();
2110	<	Segment<K,V> s = segmentForHash(hash);
1096	<	return s != null && s.replace(key, hash, oldValue, newValue);
2110	>	return new KeySetView<K,V>(this, mappedValue);
2111		}
2112
2113	+	/* ---------------- Special Nodes -------------- */
2114	+
2115		/**
2116	<	* {@inheritDoc}
1101	<	*
1102	<	* @return the previous value associated with the specified key,
1103	<	*         or <tt>null</tt> if there was no mapping for the key
1104	<	* @throws NullPointerException if the specified key or value is null
2116	>	* A node inserted at head of bins during transfer operations.
2117		*/
2118	<	public V replace(K key, V value) {
2119	<	int hash = hash(key.hashCode());
2120	<	if (value == null)
2121	<	throw new NullPointerException();
2122	<	Segment<K,V> s = segmentForHash(hash);
2123	<	return s == null ? null : s.replace(key, hash, value);
2118	>	static final class ForwardingNode<K,V> extends Node<K,V> {
2119	>	final Node<K,V>[] nextTable;
2120	>	ForwardingNode(Node<K,V>[] tab) {
2121	>	super(MOVED, null, null, null);
2122	>	this.nextTable = tab;
2123	>	}
2124	>
2125	>	Node<K,V> find(int h, Object k) {
2126	>	// loop to avoid arbitrarily deep recursion on forwarding nodes
2127	>	outer: for (Node<K,V>[] tab = nextTable;;) {
2128	>	Node<K,V> e; int n;
2129	>	if (k == null || tab == null || (n = tab.length) == 0 ||
2130	>	(e = tabAt(tab, (n - 1) & h)) == null)
2131	>	return null;
2132	>	for (;;) {
2133	>	int eh; K ek;
2134	>	if ((eh = e.hash) == h &&
2135	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2136	>	return e;
2137	>	if (eh < 0) {
2138	>	if (e instanceof ForwardingNode) {
2139	>	tab = ((ForwardingNode<K,V>)e).nextTable;
2140	>	continue outer;
2141	>	}
2142	>	else
2143	>	return e.find(h, k);
2144	>	}
2145	>	if ((e = e.next) == null)
2146	>	return null;
2147	>	}
2148	>	}
2149	>	}
2150		}
2151
2152		/**
2153	<	* Removes all of the mappings from this map.
2153	>	* A place-holder node used in computeIfAbsent and compute
2154		*/
2155	<	public void clear() {
2156	<	final Segment<K,V>[] segments = this.segments;
2157	<	for (int j = 0; j < segments.length; ++j) {
2158	<	Segment<K,V> s = segmentAt(segments, j);
2159	<	if (s != null)
2160	<	s.clear();
2155	>	static final class ReservationNode<K,V> extends Node<K,V> {
2156	>	ReservationNode() {
2157	>	super(RESERVED, null, null, null);
2158	>	}
2159	>
2160	>	Node<K,V> find(int h, Object k) {
2161	>	return null;
2162		}
2163		}
2164
2165	+	/* ---------------- Table Initialization and Resizing -------------- */
2166	+
2167		/**
2168	<	* Returns a {@link Set} view of the keys contained in this map.
2169	<	* The set is backed by the map, so changes to the map are
2170	<	* reflected in the set, and vice-versa.  The set supports element
2171	<	* removal, which removes the corresponding mapping from this map,
2172	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2173	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2174	<	* operations.  It does not support the <tt>add</tt> or
2175	<	* <tt>addAll</tt> operations.
2176	<	*
2177	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2178	<	* that will never throw {@link ConcurrentModificationException},
2179	<	* and guarantees to traverse elements as they existed upon
2180	<	* construction of the iterator, and may (but is not guaranteed to)
2181	<	* reflect any modifications subsequent to construction.
2182	<	*/
2183	<	public Set<K> keySet() {
2184	<	Set<K> ks = keySet;
2185	<	return (ks != null) ? ks : (keySet = new KeySet());
2168	>	* Initializes table, using the size recorded in sizeCtl.
2169	>	*/
2170	>	private final Node<K,V>[] initTable() {
2171	>	Node<K,V>[] tab; int sc;
2172	>	while ((tab = table) == null || tab.length == 0) {
2173	>	if ((sc = sizeCtl) < 0)
2174	>	Thread.yield(); // lost initialization race; just spin
2175	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2176	>	try {
2177	>	if ((tab = table) == null || tab.length == 0) {
2178	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
2179	>	@SuppressWarnings("unchecked")
2180	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2181	>	table = tab = nt;
2182	>	sc = n - (n >>> 2);
2183	>	}
2184	>	} finally {
2185	>	sizeCtl = sc;
2186	>	}
2187	>	break;
2188	>	}
2189	>	}
2190	>	return tab;
2191		}
2192
2193		/**
2194	<	* Returns a {@link Collection} view of the values contained in this map.
2195	<	* The collection is backed by the map, so changes to the map are
2196	<	* reflected in the collection, and vice-versa.  The collection
2197	<	* supports element removal, which removes the corresponding
2198	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
2199	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
2200	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
2201	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
1156	<	*
1157	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1158	<	* that will never throw {@link ConcurrentModificationException},
1159	<	* and guarantees to traverse elements as they existed upon
1160	<	* construction of the iterator, and may (but is not guaranteed to)
1161	<	* reflect any modifications subsequent to construction.
2194	>	* Adds to count, and if table is too small and not already
2195	>	* resizing, initiates transfer. If already resizing, helps
2196	>	* perform transfer if work is available.  Rechecks occupancy
2197	>	* after a transfer to see if another resize is already needed
2198	>	* because resizings are lagging additions.
2199	>	*
2200	>	* @param x the count to add
2201	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
2202		*/
2203	<	public Collection<V> values() {
2204	<	Collection<V> vs = values;
2205	<	return (vs != null) ? vs : (values = new Values());
2203	>	private final void addCount(long x, int check) {
2204	>	CounterCell[] as; long b, s;
2205	>	if ((as = counterCells) != null ||
2206	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
2207	>	CounterCell a; long v; int m;
2208	>	boolean uncontended = true;
2209	>	if (as == null || (m = as.length - 1) < 0 ||
2210	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
2211	>	!(uncontended =
2212	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
2213	>	fullAddCount(x, uncontended);
2214	>	return;
2215	>	}
2216	>	if (check <= 1)
2217	>	return;
2218	>	s = sumCount();
2219	>	}
2220	>	if (check >= 0) {
2221	>	Node<K,V>[] tab, nt; int sc;
2222	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
2223	>	tab.length < MAXIMUM_CAPACITY) {
2224	>	if (sc < 0) {
2225	>	if (sc == -1 || transferIndex <= 0 ||
2226	>	(nt = nextTable) == null)
2227	>	break;
2228	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
2229	>	transfer(tab, nt);
2230	>	}
2231	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
2232	>	transfer(tab, null);
2233	>	s = sumCount();
2234	>	}
2235	>	}
2236		}
2237
2238		/**
2239	<	* Returns a {@link Set} view of the mappings contained in this map.
1170	<	* The set is backed by the map, so changes to the map are
1171	<	* reflected in the set, and vice-versa.  The set supports element
1172	<	* removal, which removes the corresponding mapping from the map,
1173	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
1174	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
1175	<	* operations.  It does not support the <tt>add</tt> or
1176	<	* <tt>addAll</tt> operations.
1177	<	*
1178	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
1179	<	* that will never throw {@link ConcurrentModificationException},
1180	<	* and guarantees to traverse elements as they existed upon
1181	<	* construction of the iterator, and may (but is not guaranteed to)
1182	<	* reflect any modifications subsequent to construction.
2239	>	* Helps transfer if a resize is in progress.
2240		*/
2241	<	public Set<Map.Entry<K,V>> entrySet() {
2242	<	Set<Map.Entry<K,V>> es = entrySet;
2243	<	return (es != null) ? es : (entrySet = new EntrySet());
2241	>	final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) {
2242	>	Node<K,V>[] nextTab; int sc;
2243	>	if ((f instanceof ForwardingNode) &&
2244	>	(nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) {
2245	>	while (transferIndex > 0 && nextTab == nextTable &&
2246	>	(sc = sizeCtl) < -1) {
2247	>	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1)) {
2248	>	transfer(tab, nextTab);
2249	>	break;
2250	>	}
2251	>	}
2252	>	return nextTab;
2253	>	}
2254	>	return table;
2255		}
2256
2257		/**
2258	<	* Returns an enumeration of the keys in this table.
2258	>	* Tries to presize table to accommodate the given number of elements.
2259		*
2260	<	* @return an enumeration of the keys in this table
1193	<	* @see #keySet()
2260	>	* @param size number of elements (doesn't need to be perfectly accurate)
2261		*/
2262	<	public Enumeration<K> keys() {
2263	<	return new KeyIterator();
2262	>	private final void tryPresize(int size) {
2263	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
2264	>	tableSizeFor(size + (size >>> 1) + 1);
2265	>	int sc;
2266	>	while ((sc = sizeCtl) >= 0) {
2267	>	Node<K,V>[] tab = table; int n;
2268	>	if (tab == null || (n = tab.length) == 0) {
2269	>	n = (sc > c) ? sc : c;
2270	>	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
2271	>	try {
2272	>	if (table == tab) {
2273	>	@SuppressWarnings("unchecked")
2274	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n];
2275	>	table = nt;
2276	>	sc = n - (n >>> 2);
2277	>	}
2278	>	} finally {
2279	>	sizeCtl = sc;
2280	>	}
2281	>	}
2282	>	}
2283	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
2284	>	break;
2285	>	else if (tab == table &&
2286	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
2287	>	transfer(tab, null);
2288	>	}
2289		}
2290
2291		/**
2292	<	* Returns an enumeration of the values in this table.
2293	<	*
1202	<	* @return an enumeration of the values in this table
1203	<	* @see #values()
2292	>	* Moves and/or copies the nodes in each bin to new table. See
2293	>	* above for explanation.
2294		*/
2295	<	public Enumeration<V> elements() {
2296	<	return new ValueIterator();
2295	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
2296	>	int n = tab.length, stride;
2297	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
2298	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
2299	>	if (nextTab == null) {            // initiating
2300	>	try {
2301	>	@SuppressWarnings("unchecked")
2302	>	Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1];
2303	>	nextTab = nt;
2304	>	} catch (Throwable ex) {      // try to cope with OOME
2305	>	sizeCtl = Integer.MAX_VALUE;
2306	>	return;
2307	>	}
2308	>	nextTable = nextTab;
2309	>	transferIndex = n;
2310	>	}
2311	>	int nextn = nextTab.length;
2312	>	ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab);
2313	>	boolean advance = true;
2314	>	boolean finishing = false; // to ensure sweep before committing nextTab
2315	>	for (int i = 0, bound = 0;;) {
2316	>	Node<K,V> f; int fh;
2317	>	while (advance) {
2318	>	int nextIndex, nextBound;
2319	>	if (--i >= bound || finishing)
2320	>	advance = false;
2321	>	else if ((nextIndex = transferIndex) <= 0) {
2322	>	i = -1;
2323	>	advance = false;
2324	>	}
2325	>	else if (U.compareAndSwapInt
2326	>	(this, TRANSFERINDEX, nextIndex,
2327	>	nextBound = (nextIndex > stride ?
2328	>	nextIndex - stride : 0))) {
2329	>	bound = nextBound;
2330	>	i = nextIndex - 1;
2331	>	advance = false;
2332	>	}
2333	>	}
2334	>	if (i < 0 || i >= n || i + n >= nextn) {
2335	>	int sc;
2336	>	if (finishing) {
2337	>	nextTable = null;
2338	>	table = nextTab;
2339	>	sizeCtl = (n << 1) - (n >>> 1);
2340	>	return;
2341	>	}
2342	>	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
2343	>	if (sc != -1)
2344	>	return;
2345	>	finishing = advance = true;
2346	>	i = n; // recheck before commit
2347	>	}
2348	>	}
2349	>	else if ((f = tabAt(tab, i)) == null)
2350	>	advance = casTabAt(tab, i, null, fwd);
2351	>	else if ((fh = f.hash) == MOVED)
2352	>	advance = true; // already processed
2353	>	else {
2354	>	synchronized (f) {
2355	>	if (tabAt(tab, i) == f) {
2356	>	Node<K,V> ln, hn;
2357	>	if (fh >= 0) {
2358	>	int runBit = fh & n;
2359	>	Node<K,V> lastRun = f;
2360	>	for (Node<K,V> p = f.next; p != null; p = p.next) {
2361	>	int b = p.hash & n;
2362	>	if (b != runBit) {
2363	>	runBit = b;
2364	>	lastRun = p;
2365	>	}
2366	>	}
2367	>	if (runBit == 0) {
2368	>	ln = lastRun;
2369	>	hn = null;
2370	>	}
2371	>	else {
2372	>	hn = lastRun;
2373	>	ln = null;
2374	>	}
2375	>	for (Node<K,V> p = f; p != lastRun; p = p.next) {
2376	>	int ph = p.hash; K pk = p.key; V pv = p.val;
2377	>	if ((ph & n) == 0)
2378	>	ln = new Node<K,V>(ph, pk, pv, ln);
2379	>	else
2380	>	hn = new Node<K,V>(ph, pk, pv, hn);
2381	>	}
2382	>	setTabAt(nextTab, i, ln);
2383	>	setTabAt(nextTab, i + n, hn);
2384	>	setTabAt(tab, i, fwd);
2385	>	advance = true;
2386	>	}
2387	>	else if (f instanceof TreeBin) {
2388	>	TreeBin<K,V> t = (TreeBin<K,V>)f;
2389	>	TreeNode<K,V> lo = null, loTail = null;
2390	>	TreeNode<K,V> hi = null, hiTail = null;
2391	>	int lc = 0, hc = 0;
2392	>	for (Node<K,V> e = t.first; e != null; e = e.next) {
2393	>	int h = e.hash;
2394	>	TreeNode<K,V> p = new TreeNode<K,V>
2395	>	(h, e.key, e.val, null, null);
2396	>	if ((h & n) == 0) {
2397	>	if ((p.prev = loTail) == null)
2398	>	lo = p;
2399	>	else
2400	>	loTail.next = p;
2401	>	loTail = p;
2402	>	++lc;
2403	>	}
2404	>	else {
2405	>	if ((p.prev = hiTail) == null)
2406	>	hi = p;
2407	>	else
2408	>	hiTail.next = p;
2409	>	hiTail = p;
2410	>	++hc;
2411	>	}
2412	>	}
2413	>	ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) :
2414	>	(hc != 0) ? new TreeBin<K,V>(lo) : t;
2415	>	hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) :
2416	>	(lc != 0) ? new TreeBin<K,V>(hi) : t;
2417	>	setTabAt(nextTab, i, ln);
2418	>	setTabAt(nextTab, i + n, hn);
2419	>	setTabAt(tab, i, fwd);
2420	>	advance = true;
2421	>	}
2422	>	}
2423	>	}
2424	>	}
2425	>	}
2426		}
2427
2428	<	/* ---------------- Iterator Support -------------- */
2428	>	/* ---------------- Counter support -------------- */
2429
2430	<	abstract class HashIterator {
2431	<	int nextSegmentIndex;
2432	<	int nextTableIndex;
2433	<	HashEntry<K,V>[] currentTable;
2434	<	HashEntry<K, V> nextEntry;
2435	<	HashEntry<K, V> lastReturned;
2430	>	/**
2431	>	* A padded cell for distributing counts.  Adapted from LongAdder
2432	>	* and Striped64.  See their internal docs for explanation.
2433	>	*/
2434	>	@sun.misc.Contended static final class CounterCell {
2435	>	volatile long value;
2436	>	CounterCell(long x) { value = x; }
2437	>	}
2438
2439	<	HashIterator() {
2440	<	nextSegmentIndex = segments.length - 1;
2441	<	nextTableIndex = -1;
2442	<	advance();
2439	>	final long sumCount() {
2440	>	CounterCell[] as = counterCells; CounterCell a;
2441	>	long sum = baseCount;
2442	>	if (as != null) {
2443	>	for (int i = 0; i < as.length; ++i) {
2444	>	if ((a = as[i]) != null)
2445	>	sum += a.value;
2446	>	}
2447	>	}
2448	>	return sum;
2449	>	}
2450	>
2451	>	// See LongAdder version for explanation
2452	>	private final void fullAddCount(long x, boolean wasUncontended) {
2453	>	int h;
2454	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2455	>	ThreadLocalRandom.localInit();      // force initialization
2456	>	h = ThreadLocalRandom.getProbe();
2457	>	wasUncontended = true;
2458	>	}
2459	>	boolean collide = false;                // True if last slot nonempty
2460	>	for (;;) {
2461	>	CounterCell[] as; CounterCell a; int n; long v;
2462	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2463	>	if ((a = as[(n - 1) & h]) == null) {
2464	>	if (cellsBusy == 0) {            // Try to attach new Cell
2465	>	CounterCell r = new CounterCell(x); // Optimistic create
2466	>	if (cellsBusy == 0 &&
2467	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2468	>	boolean created = false;
2469	>	try {               // Recheck under lock
2470	>	CounterCell[] rs; int m, j;
2471	>	if ((rs = counterCells) != null &&
2472	>	(m = rs.length) > 0 &&
2473	>	rs[j = (m - 1) & h] == null) {
2474	>	rs[j] = r;
2475	>	created = true;
2476	>	}
2477	>	} finally {
2478	>	cellsBusy = 0;
2479	>	}
2480	>	if (created)
2481	>	break;
2482	>	continue;           // Slot is now non-empty
2483	>	}
2484	>	}
2485	>	collide = false;
2486	>	}
2487	>	else if (!wasUncontended)       // CAS already known to fail
2488	>	wasUncontended = true;      // Continue after rehash
2489	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2490	>	break;
2491	>	else if (counterCells != as || n >= NCPU)
2492	>	collide = false;            // At max size or stale
2493	>	else if (!collide)
2494	>	collide = true;
2495	>	else if (cellsBusy == 0 &&
2496	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2497	>	try {
2498	>	if (counterCells == as) {// Expand table unless stale
2499	>	CounterCell[] rs = new CounterCell[n << 1];
2500	>	for (int i = 0; i < n; ++i)
2501	>	rs[i] = as[i];
2502	>	counterCells = rs;
2503	>	}
2504	>	} finally {
2505	>	cellsBusy = 0;
2506	>	}
2507	>	collide = false;
2508	>	continue;                   // Retry with expanded table
2509	>	}
2510	>	h = ThreadLocalRandom.advanceProbe(h);
2511	>	}
2512	>	else if (cellsBusy == 0 && counterCells == as &&
2513	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2514	>	boolean init = false;
2515	>	try {                           // Initialize table
2516	>	if (counterCells == as) {
2517	>	CounterCell[] rs = new CounterCell[2];
2518	>	rs[h & 1] = new CounterCell(x);
2519	>	counterCells = rs;
2520	>	init = true;
2521	>	}
2522	>	} finally {
2523	>	cellsBusy = 0;
2524	>	}
2525	>	if (init)
2526	>	break;
2527	>	}
2528	>	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2529	>	break;                          // Fall back on using base
2530	>	}
2531	>	}
2532	>
2533	>	/* ---------------- Conversion from/to TreeBins -------------- */
2534	>
2535	>	/**
2536	>	* Replaces all linked nodes in bin at given index unless table is
2537	>	* too small, in which case resizes instead.
2538	>	*/
2539	>	private final void treeifyBin(Node<K,V>[] tab, int index) {
2540	>	Node<K,V> b; int n, sc;
2541	>	if (tab != null) {
2542	>	if ((n = tab.length) < MIN_TREEIFY_CAPACITY) {
2543	>	if (tab == table && (sc = sizeCtl) >= 0 &&
2544	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
2545	>	transfer(tab, null);
2546	>	}
2547	>	else if ((b = tabAt(tab, index)) != null && b.hash >= 0) {
2548	>	synchronized (b) {
2549	>	if (tabAt(tab, index) == b) {
2550	>	TreeNode<K,V> hd = null, tl = null;
2551	>	for (Node<K,V> e = b; e != null; e = e.next) {
2552	>	TreeNode<K,V> p =
2553	>	new TreeNode<K,V>(e.hash, e.key, e.val,
2554	>	null, null);
2555	>	if ((p.prev = tl) == null)
2556	>	hd = p;
2557	>	else
2558	>	tl.next = p;
2559	>	tl = p;
2560	>	}
2561	>	setTabAt(tab, index, new TreeBin<K,V>(hd));
2562	>	}
2563	>	}
2564	>	}
2565	>	}
2566	>	}
2567	>
2568	>	/**
2569	>	* Returns a list on non-TreeNodes replacing those in given list.
2570	>	*/
2571	>	static <K,V> Node<K,V> untreeify(Node<K,V> b) {
2572	>	Node<K,V> hd = null, tl = null;
2573	>	for (Node<K,V> q = b; q != null; q = q.next) {
2574	>	Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null);
2575	>	if (tl == null)
2576	>	hd = p;
2577	>	else
2578	>	tl.next = p;
2579	>	tl = p;
2580	>	}
2581	>	return hd;
2582	>	}
2583	>
2584	>	/* ---------------- TreeNodes -------------- */
2585	>
2586	>	/**
2587	>	* Nodes for use in TreeBins
2588	>	*/
2589	>	static final class TreeNode<K,V> extends Node<K,V> {
2590	>	TreeNode<K,V> parent;  // red-black tree links
2591	>	TreeNode<K,V> left;
2592	>	TreeNode<K,V> right;
2593	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
2594	>	boolean red;
2595	>
2596	>	TreeNode(int hash, K key, V val, Node<K,V> next,
2597	>	TreeNode<K,V> parent) {
2598	>	super(hash, key, val, next);
2599	>	this.parent = parent;
2600	>	}
2601	>
2602	>	Node<K,V> find(int h, Object k) {
2603	>	return findTreeNode(h, k, null);
2604		}
2605
2606		/**
2607	<	* Sets nextEntry to first node of next non-empty table
2608	<	* (in backwards order, to simplify checks).
2607	>	* Returns the TreeNode (or null if not found) for the given key
2608	>	* starting at given root.
2609		*/
2610	<	final void advance() {
2611	<	for (;;) {
2612	<	if (nextTableIndex >= 0) {
2613	<	if ((nextEntry = entryAt(currentTable,
2614	<	nextTableIndex--)) != null)
2615	<	break;
2610	>	final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) {
2611	>	if (k != null) {
2612	>	TreeNode<K,V> p = this;
2613	>	do  {
2614	>	int ph, dir; K pk; TreeNode<K,V> q;
2615	>	TreeNode<K,V> pl = p.left, pr = p.right;
2616	>	if ((ph = p.hash) > h)
2617	>	p = pl;
2618	>	else if (ph < h)
2619	>	p = pr;
2620	>	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2621	>	return p;
2622	>	else if (pl == null)
2623	>	p = pr;
2624	>	else if (pr == null)
2625	>	p = pl;
2626	>	else if ((kc != null ||
2627	>	(kc = comparableClassFor(k)) != null) &&
2628	>	(dir = compareComparables(kc, k, pk)) != 0)
2629	>	p = (dir < 0) ? pl : pr;
2630	>	else if ((q = pr.findTreeNode(h, k, kc)) != null)
2631	>	return q;
2632	>	else
2633	>	p = pl;
2634	>	} while (p != null);
2635	>	}
2636	>	return null;
2637	>	}
2638	>	}
2639	>
2640	>	/* ---------------- TreeBins -------------- */
2641	>
2642	>	/**
2643	>	* TreeNodes used at the heads of bins. TreeBins do not hold user
2644	>	* keys or values, but instead point to list of TreeNodes and
2645	>	* their root. They also maintain a parasitic read-write lock
2646	>	* forcing writers (who hold bin lock) to wait for readers (who do
2647	>	* not) to complete before tree restructuring operations.
2648	>	*/
2649	>	static final class TreeBin<K,V> extends Node<K,V> {
2650	>	TreeNode<K,V> root;
2651	>	volatile TreeNode<K,V> first;
2652	>	volatile Thread waiter;
2653	>	volatile int lockState;
2654	>	// values for lockState
2655	>	static final int WRITER = 1; // set while holding write lock
2656	>	static final int WAITER = 2; // set when waiting for write lock
2657	>	static final int READER = 4; // increment value for setting read lock
2658	>
2659	>	/**
2660	>	* Tie-breaking utility for ordering insertions when equal
2661	>	* hashCodes and non-comparable. We don't require a total
2662	>	* order, just a consistent insertion rule to maintain
2663	>	* equivalence across rebalancings. Tie-breaking further than
2664	>	* necessary simplifies testing a bit.
2665	>	*/
2666	>	static int tieBreakOrder(Object a, Object b) {
2667	>	int d;
2668	>	if (a == null || b == null ||
2669	>	(d = a.getClass().getName().
2670	>	compareTo(b.getClass().getName())) == 0)
2671	>	d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
2672	>	-1 : 1);
2673	>	return d;
2674	>	}
2675	>
2676	>	/**
2677	>	* Creates bin with initial set of nodes headed by b.
2678	>	*/
2679	>	TreeBin(TreeNode<K,V> b) {
2680	>	super(TREEBIN, null, null, null);
2681	>	this.first = b;
2682	>	TreeNode<K,V> r = null;
2683	>	for (TreeNode<K,V> x = b, next; x != null; x = next) {
2684	>	next = (TreeNode<K,V>)x.next;
2685	>	x.left = x.right = null;
2686	>	if (r == null) {
2687	>	x.parent = null;
2688	>	x.red = false;
2689	>	r = x;
2690		}
2691	<	else if (nextSegmentIndex >= 0) {
2692	<	Segment<K,V> seg = segmentAt(segments, nextSegmentIndex--);
2693	<	if (seg != null && (currentTable = seg.table) != null)
2694	<	nextTableIndex = currentTable.length - 1;
2691	>	else {
2692	>	K k = x.key;
2693	>	int h = x.hash;
2694	>	Class<?> kc = null;
2695	>	for (TreeNode<K,V> p = r;;) {
2696	>	int dir, ph;
2697	>	K pk = p.key;
2698	>	if ((ph = p.hash) > h)
2699	>	dir = -1;
2700	>	else if (ph < h)
2701	>	dir = 1;
2702	>	else if ((kc == null &&
2703	>	(kc = comparableClassFor(k)) == null) ||
2704	>	(dir = compareComparables(kc, k, pk)) == 0)
2705	>	dir = tieBreakOrder(k, pk);
2706	>	TreeNode<K,V> xp = p;
2707	>	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2708	>	x.parent = xp;
2709	>	if (dir <= 0)
2710	>	xp.left = x;
2711	>	else
2712	>	xp.right = x;
2713	>	r = balanceInsertion(r, x);
2714	>	break;
2715	>	}
2716	>	}
2717		}
2718	<	else
2718	>	}
2719	>	this.root = r;
2720	>	assert checkInvariants(root);
2721	>	}
2722	>
2723	>	/**
2724	>	* Acquires write lock for tree restructuring.
2725	>	*/
2726	>	private final void lockRoot() {
2727	>	if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER))
2728	>	contendedLock(); // offload to separate method
2729	>	}
2730	>
2731	>	/**
2732	>	* Releases write lock for tree restructuring.
2733	>	*/
2734	>	private final void unlockRoot() {
2735	>	lockState = 0;
2736	>	}
2737	>
2738	>	/**
2739	>	* Possibly blocks awaiting root lock.
2740	>	*/
2741	>	private final void contendedLock() {
2742	>	boolean waiting = false;
2743	>	for (int s;;) {
2744	>	if (((s = lockState) & WRITER) == 0) {
2745	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) {
2746	>	if (waiting)
2747	>	waiter = null;
2748	>	return;
2749	>	}
2750	>	}
2751	>	else if ((s & WAITER) == 0) {
2752	>	if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) {
2753	>	waiting = true;
2754	>	waiter = Thread.currentThread();
2755	>	}
2756	>	}
2757	>	else if (waiting)
2758	>	LockSupport.park(this);
2759	>	}
2760	>	}
2761	>
2762	>	/**
2763	>	* Returns matching node or null if none. Tries to search
2764	>	* using tree comparisons from root, but continues linear
2765	>	* search when lock not available.
2766	>	*/
2767	>	final Node<K,V> find(int h, Object k) {
2768	>	if (k != null) {
2769	>	for (Node<K,V> e = first; e != null; e = e.next) {
2770	>	int s; K ek;
2771	>	if (((s = lockState) & (WAITER|WRITER)) != 0) {
2772	>	if (e.hash == h &&
2773	>	((ek = e.key) == k || (ek != null && k.equals(ek))))
2774	>	return e;
2775	>	}
2776	>	else if (U.compareAndSwapInt(this, LOCKSTATE, s,
2777	>	s + READER)) {
2778	>	TreeNode<K,V> r, p;
2779	>	try {
2780	>	p = ((r = root) == null ? null :
2781	>	r.findTreeNode(h, k, null));
2782	>	} finally {
2783	>	Thread w;
2784	>	if (U.getAndAddInt(this, LOCKSTATE, -READER) ==
2785	>	(READER|WAITER) && (w = waiter) != null)
2786	>	LockSupport.unpark(w);
2787	>	}
2788	>	return p;
2789	>	}
2790	>	}
2791	>	}
2792	>	return null;
2793	>	}
2794	>
2795	>	/**
2796	>	* Finds or adds a node.
2797	>	* @return null if added
2798	>	*/
2799	>	final TreeNode<K,V> putTreeVal(int h, K k, V v) {
2800	>	Class<?> kc = null;
2801	>	boolean searched = false;
2802	>	for (TreeNode<K,V> p = root;;) {
2803	>	int dir, ph; K pk;
2804	>	if (p == null) {
2805	>	first = root = new TreeNode<K,V>(h, k, v, null, null);
2806		break;
2807	+	}
2808	+	else if ((ph = p.hash) > h)
2809	+	dir = -1;
2810	+	else if (ph < h)
2811	+	dir = 1;
2812	+	else if ((pk = p.key) == k || (pk != null && k.equals(pk)))
2813	+	return p;
2814	+	else if ((kc == null &&
2815	+	(kc = comparableClassFor(k)) == null) ||
2816	+	(dir = compareComparables(kc, k, pk)) == 0) {
2817	+	if (!searched) {
2818	+	TreeNode<K,V> q, ch;
2819	+	searched = true;
2820	+	if (((ch = p.left) != null &&
2821	+	(q = ch.findTreeNode(h, k, kc)) != null) ||
2822	+	((ch = p.right) != null &&
2823	+	(q = ch.findTreeNode(h, k, kc)) != null))
2824	+	return q;
2825	+	}
2826	+	dir = tieBreakOrder(k, pk);
2827	+	}
2828	+
2829	+	TreeNode<K,V> xp = p;
2830	+	if ((p = (dir <= 0) ? p.left : p.right) == null) {
2831	+	TreeNode<K,V> x, f = first;
2832	+	first = x = new TreeNode<K,V>(h, k, v, f, xp);
2833	+	if (f != null)
2834	+	f.prev = x;
2835	+	if (dir <= 0)
2836	+	xp.left = x;
2837	+	else
2838	+	xp.right = x;
2839	+	if (!xp.red)
2840	+	x.red = true;
2841	+	else {
2842	+	lockRoot();
2843	+	try {
2844	+	root = balanceInsertion(root, x);
2845	+	} finally {
2846	+	unlockRoot();
2847	+	}
2848	+	}
2849	+	break;
2850	+	}
2851		}
2852	+	assert checkInvariants(root);
2853	+	return null;
2854		}
2855
2856	<	final HashEntry<K,V> nextEntry() {
2857	<	HashEntry<K,V> e = nextEntry;
2858	<	if (e == null)
2859	<	throw new NoSuchElementException();
2860	<	lastReturned = e; // cannot assign until after null check
2861	<	if ((nextEntry = e.next) == null)
2862	<	advance();
2863	<	return e;
2856	>	/**
2857	>	* Removes the given node, that must be present before this
2858	>	* call.  This is messier than typical red-black deletion code
2859	>	* because we cannot swap the contents of an interior node
2860	>	* with a leaf successor that is pinned by "next" pointers
2861	>	* that are accessible independently of lock. So instead we
2862	>	* swap the tree linkages.
2863	>	*
2864	>	* @return true if now too small, so should be untreeified
2865	>	*/
2866	>	final boolean removeTreeNode(TreeNode<K,V> p) {
2867	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
2868	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
2869	>	TreeNode<K,V> r, rl;
2870	>	if (pred == null)
2871	>	first = next;
2872	>	else
2873	>	pred.next = next;
2874	>	if (next != null)
2875	>	next.prev = pred;
2876	>	if (first == null) {
2877	>	root = null;
2878	>	return true;
2879	>	}
2880	>	if ((r = root) == null || r.right == null || // too small
2881	>	(rl = r.left) == null || rl.left == null)
2882	>	return true;
2883	>	lockRoot();
2884	>	try {
2885	>	TreeNode<K,V> replacement;
2886	>	TreeNode<K,V> pl = p.left;
2887	>	TreeNode<K,V> pr = p.right;
2888	>	if (pl != null && pr != null) {
2889	>	TreeNode<K,V> s = pr, sl;
2890	>	while ((sl = s.left) != null) // find successor
2891	>	s = sl;
2892	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2893	>	TreeNode<K,V> sr = s.right;
2894	>	TreeNode<K,V> pp = p.parent;
2895	>	if (s == pr) { // p was s's direct parent
2896	>	p.parent = s;
2897	>	s.right = p;
2898	>	}
2899	>	else {
2900	>	TreeNode<K,V> sp = s.parent;
2901	>	if ((p.parent = sp) != null) {
2902	>	if (s == sp.left)
2903	>	sp.left = p;
2904	>	else
2905	>	sp.right = p;
2906	>	}
2907	>	if ((s.right = pr) != null)
2908	>	pr.parent = s;
2909	>	}
2910	>	p.left = null;
2911	>	if ((p.right = sr) != null)
2912	>	sr.parent = p;
2913	>	if ((s.left = pl) != null)
2914	>	pl.parent = s;
2915	>	if ((s.parent = pp) == null)
2916	>	r = s;
2917	>	else if (p == pp.left)
2918	>	pp.left = s;
2919	>	else
2920	>	pp.right = s;
2921	>	if (sr != null)
2922	>	replacement = sr;
2923	>	else
2924	>	replacement = p;
2925	>	}
2926	>	else if (pl != null)
2927	>	replacement = pl;
2928	>	else if (pr != null)
2929	>	replacement = pr;
2930	>	else
2931	>	replacement = p;
2932	>	if (replacement != p) {
2933	>	TreeNode<K,V> pp = replacement.parent = p.parent;
2934	>	if (pp == null)
2935	>	r = replacement;
2936	>	else if (p == pp.left)
2937	>	pp.left = replacement;
2938	>	else
2939	>	pp.right = replacement;
2940	>	p.left = p.right = p.parent = null;
2941	>	}
2942	>
2943	>	root = (p.red) ? r : balanceDeletion(r, replacement);
2944	>
2945	>	if (p == replacement) {  // detach pointers
2946	>	TreeNode<K,V> pp;
2947	>	if ((pp = p.parent) != null) {
2948	>	if (p == pp.left)
2949	>	pp.left = null;
2950	>	else if (p == pp.right)
2951	>	pp.right = null;
2952	>	p.parent = null;
2953	>	}
2954	>	}
2955	>	} finally {
2956	>	unlockRoot();
2957	>	}
2958	>	assert checkInvariants(root);
2959	>	return false;
2960	>	}
2961	>
2962	>	/* ------------------------------------------------------------ */
2963	>	// Red-black tree methods, all adapted from CLR
2964	>
2965	>	static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
2966	>	TreeNode<K,V> p) {
2967	>	TreeNode<K,V> r, pp, rl;
2968	>	if (p != null && (r = p.right) != null) {
2969	>	if ((rl = p.right = r.left) != null)
2970	>	rl.parent = p;
2971	>	if ((pp = r.parent = p.parent) == null)
2972	>	(root = r).red = false;
2973	>	else if (pp.left == p)
2974	>	pp.left = r;
2975	>	else
2976	>	pp.right = r;
2977	>	r.left = p;
2978	>	p.parent = r;
2979	>	}
2980	>	return root;
2981	>	}
2982	>
2983	>	static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
2984	>	TreeNode<K,V> p) {
2985	>	TreeNode<K,V> l, pp, lr;
2986	>	if (p != null && (l = p.left) != null) {
2987	>	if ((lr = p.left = l.right) != null)
2988	>	lr.parent = p;
2989	>	if ((pp = l.parent = p.parent) == null)
2990	>	(root = l).red = false;
2991	>	else if (pp.right == p)
2992	>	pp.right = l;
2993	>	else
2994	>	pp.left = l;
2995	>	l.right = p;
2996	>	p.parent = l;
2997	>	}
2998	>	return root;
2999		}
3000
3001	<	public final boolean hasNext() { return nextEntry != null; }
3002	<	public final boolean hasMoreElements() { return nextEntry != null; }
3001	>	static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
3002	>	TreeNode<K,V> x) {
3003	>	x.red = true;
3004	>	for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
3005	>	if ((xp = x.parent) == null) {
3006	>	x.red = false;
3007	>	return x;
3008	>	}
3009	>	else if (!xp.red || (xpp = xp.parent) == null)
3010	>	return root;
3011	>	if (xp == (xppl = xpp.left)) {
3012	>	if ((xppr = xpp.right) != null && xppr.red) {
3013	>	xppr.red = false;
3014	>	xp.red = false;
3015	>	xpp.red = true;
3016	>	x = xpp;
3017	>	}
3018	>	else {
3019	>	if (x == xp.right) {
3020	>	root = rotateLeft(root, x = xp);
3021	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3022	>	}
3023	>	if (xp != null) {
3024	>	xp.red = false;
3025	>	if (xpp != null) {
3026	>	xpp.red = true;
3027	>	root = rotateRight(root, xpp);
3028	>	}
3029	>	}
3030	>	}
3031	>	}
3032	>	else {
3033	>	if (xppl != null && xppl.red) {
3034	>	xppl.red = false;
3035	>	xp.red = false;
3036	>	xpp.red = true;
3037	>	x = xpp;
3038	>	}
3039	>	else {
3040	>	if (x == xp.left) {
3041	>	root = rotateRight(root, x = xp);
3042	>	xpp = (xp = x.parent) == null ? null : xp.parent;
3043	>	}
3044	>	if (xp != null) {
3045	>	xp.red = false;
3046	>	if (xpp != null) {
3047	>	xpp.red = true;
3048	>	root = rotateLeft(root, xpp);
3049	>	}
3050	>	}
3051	>	}
3052	>	}
3053	>	}
3054	>	}
3055	>
3056	>	static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
3057	>	TreeNode<K,V> x) {
3058	>	for (TreeNode<K,V> xp, xpl, xpr;;)  {
3059	>	if (x == null || x == root)
3060	>	return root;
3061	>	else if ((xp = x.parent) == null) {
3062	>	x.red = false;
3063	>	return x;
3064	>	}
3065	>	else if (x.red) {
3066	>	x.red = false;
3067	>	return root;
3068	>	}
3069	>	else if ((xpl = xp.left) == x) {
3070	>	if ((xpr = xp.right) != null && xpr.red) {
3071	>	xpr.red = false;
3072	>	xp.red = true;
3073	>	root = rotateLeft(root, xp);
3074	>	xpr = (xp = x.parent) == null ? null : xp.right;
3075	>	}
3076	>	if (xpr == null)
3077	>	x = xp;
3078	>	else {
3079	>	TreeNode<K,V> sl = xpr.left, sr = xpr.right;
3080	>	if ((sr == null || !sr.red) &&
3081	>	(sl == null || !sl.red)) {
3082	>	xpr.red = true;
3083	>	x = xp;
3084	>	}
3085	>	else {
3086	>	if (sr == null || !sr.red) {
3087	>	if (sl != null)
3088	>	sl.red = false;
3089	>	xpr.red = true;
3090	>	root = rotateRight(root, xpr);
3091	>	xpr = (xp = x.parent) == null ?
3092	>	null : xp.right;
3093	>	}
3094	>	if (xpr != null) {
3095	>	xpr.red = (xp == null) ? false : xp.red;
3096	>	if ((sr = xpr.right) != null)
3097	>	sr.red = false;
3098	>	}
3099	>	if (xp != null) {
3100	>	xp.red = false;
3101	>	root = rotateLeft(root, xp);
3102	>	}
3103	>	x = root;
3104	>	}
3105	>	}
3106	>	}
3107	>	else { // symmetric
3108	>	if (xpl != null && xpl.red) {
3109	>	xpl.red = false;
3110	>	xp.red = true;
3111	>	root = rotateRight(root, xp);
3112	>	xpl = (xp = x.parent) == null ? null : xp.left;
3113	>	}
3114	>	if (xpl == null)
3115	>	x = xp;
3116	>	else {
3117	>	TreeNode<K,V> sl = xpl.left, sr = xpl.right;
3118	>	if ((sl == null || !sl.red) &&
3119	>	(sr == null || !sr.red)) {
3120	>	xpl.red = true;
3121	>	x = xp;
3122	>	}
3123	>	else {
3124	>	if (sl == null || !sl.red) {
3125	>	if (sr != null)
3126	>	sr.red = false;
3127	>	xpl.red = true;
3128	>	root = rotateLeft(root, xpl);
3129	>	xpl = (xp = x.parent) == null ?
3130	>	null : xp.left;
3131	>	}
3132	>	if (xpl != null) {
3133	>	xpl.red = (xp == null) ? false : xp.red;
3134	>	if ((sl = xpl.left) != null)
3135	>	sl.red = false;
3136	>	}
3137	>	if (xp != null) {
3138	>	xp.red = false;
3139	>	root = rotateRight(root, xp);
3140	>	}
3141	>	x = root;
3142	>	}
3143	>	}
3144	>	}
3145	>	}
3146	>	}
3147	>
3148	>	/**
3149	>	* Recursive invariant check
3150	>	*/
3151	>	static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
3152	>	TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
3153	>	tb = t.prev, tn = (TreeNode<K,V>)t.next;
3154	>	if (tb != null && tb.next != t)
3155	>	return false;
3156	>	if (tn != null && tn.prev != t)
3157	>	return false;
3158	>	if (tp != null && t != tp.left && t != tp.right)
3159	>	return false;
3160	>	if (tl != null && (tl.parent != t || tl.hash > t.hash))
3161	>	return false;
3162	>	if (tr != null && (tr.parent != t || tr.hash < t.hash))
3163	>	return false;
3164	>	if (t.red && tl != null && tl.red && tr != null && tr.red)
3165	>	return false;
3166	>	if (tl != null && !checkInvariants(tl))
3167	>	return false;
3168	>	if (tr != null && !checkInvariants(tr))
3169	>	return false;
3170	>	return true;
3171	>	}
3172	>
3173	>	private static final sun.misc.Unsafe U;
3174	>	private static final long LOCKSTATE;
3175	>	static {
3176	>	try {
3177	>	U = sun.misc.Unsafe.getUnsafe();
3178	>	Class<?> k = TreeBin.class;
3179	>	LOCKSTATE = U.objectFieldOffset
3180	>	(k.getDeclaredField("lockState"));
3181	>	} catch (Exception e) {
3182	>	throw new Error(e);
3183	>	}
3184	>	}
3185	>	}
3186	>
3187	>	/* ----------------Table Traversal -------------- */
3188	>
3189	>	/**
3190	>	* Records the table, its length, and current traversal index for a
3191	>	* traverser that must process a region of a forwarded table before
3192	>	* proceeding with current table.
3193	>	*/
3194	>	static final class TableStack<K,V> {
3195	>	int length;
3196	>	int index;
3197	>	Node<K,V>[] tab;
3198	>	TableStack<K,V> next;
3199	>	}
3200	>
3201	>	/**
3202	>	* Encapsulates traversal for methods such as containsValue; also
3203	>	* serves as a base class for other iterators and spliterators.
3204	>	*
3205	>	* Method advance visits once each still-valid node that was
3206	>	* reachable upon iterator construction. It might miss some that
3207	>	* were added to a bin after the bin was visited, which is OK wrt
3208	>	* consistency guarantees. Maintaining this property in the face
3209	>	* of possible ongoing resizes requires a fair amount of
3210	>	* bookkeeping state that is difficult to optimize away amidst
3211	>	* volatile accesses.  Even so, traversal maintains reasonable
3212	>	* throughput.
3213	>	*
3214	>	* Normally, iteration proceeds bin-by-bin traversing lists.
3215	>	* However, if the table has been resized, then all future steps
3216	>	* must traverse both the bin at the current index as well as at
3217	>	* (index + baseSize); and so on for further resizings. To
3218	>	* paranoically cope with potential sharing by users of iterators
3219	>	* across threads, iteration terminates if a bounds checks fails
3220	>	* for a table read.
3221	>	*/
3222	>	static class Traverser<K,V> {
3223	>	Node<K,V>[] tab;        // current table; updated if resized
3224	>	Node<K,V> next;         // the next entry to use
3225	>	TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes
3226	>	int index;              // index of bin to use next
3227	>	int baseIndex;          // current index of initial table
3228	>	int baseLimit;          // index bound for initial table
3229	>	final int baseSize;     // initial table size
3230	>
3231	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
3232	>	this.tab = tab;
3233	>	this.baseSize = size;
3234	>	this.baseIndex = this.index = index;
3235	>	this.baseLimit = limit;
3236	>	this.next = null;
3237	>	}
3238	>
3239	>	/**
3240	>	* Advances if possible, returning next valid node, or null if none.
3241	>	*/
3242	>	final Node<K,V> advance() {
3243	>	Node<K,V> e;
3244	>	if ((e = next) != null)
3245	>	e = e.next;
3246	>	for (;;) {
3247	>	Node<K,V>[] t; int i, n;  // must use locals in checks
3248	>	if (e != null)
3249	>	return next = e;
3250	>	if (baseIndex >= baseLimit || (t = tab) == null ||
3251	>	(n = t.length) <= (i = index) || i < 0)
3252	>	return next = null;
3253	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
3254	>	if (e instanceof ForwardingNode) {
3255	>	tab = ((ForwardingNode<K,V>)e).nextTable;
3256	>	e = null;
3257	>	pushState(t, i, n);
3258	>	continue;
3259	>	}
3260	>	else if (e instanceof TreeBin)
3261	>	e = ((TreeBin<K,V>)e).first;
3262	>	else
3263	>	e = null;
3264	>	}
3265	>	if (stack != null)
3266	>	recoverState(n);
3267	>	else if ((index = i + baseSize) >= n)
3268	>	index = ++baseIndex; // visit upper slots if present
3269	>	}
3270	>	}
3271	>
3272	>	/**
3273	>	* Saves traversal state upon encountering a forwarding node.
3274	>	*/
3275	>	private void pushState(Node<K,V>[] t, int i, int n) {
3276	>	TableStack<K,V> s = spare;  // reuse if possible
3277	>	if (s != null)
3278	>	spare = s.next;
3279	>	else
3280	>	s = new TableStack<K,V>();
3281	>	s.tab = t;
3282	>	s.length = n;
3283	>	s.index = i;
3284	>	s.next = stack;
3285	>	stack = s;
3286	>	}
3287	>
3288	>	/**
3289	>	* Possibly pops traversal state.
3290	>	*
3291	>	* @param n length of current table
3292	>	*/
3293	>	private void recoverState(int n) {
3294	>	TableStack<K,V> s; int len;
3295	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
3296	>	n = len;
3297	>	index = s.index;
3298	>	tab = s.tab;
3299	>	s.tab = null;
3300	>	TableStack<K,V> next = s.next;
3301	>	s.next = spare; // save for reuse
3302	>	stack = next;
3303	>	spare = s;
3304	>	}
3305	>	if (s == null && (index += baseSize) >= n)
3306	>	index = ++baseIndex;
3307	>	}
3308	>	}
3309	>
3310	>	/**
3311	>	* Base of key, value, and entry Iterators. Adds fields to
3312	>	* Traverser to support iterator.remove.
3313	>	*/
3314	>	static class BaseIterator<K,V> extends Traverser<K,V> {
3315	>	final ConcurrentHashMap<K,V> map;
3316	>	Node<K,V> lastReturned;
3317	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
3318	>	ConcurrentHashMap<K,V> map) {
3319	>	super(tab, size, index, limit);
3320	>	this.map = map;
3321	>	advance();
3322	>	}
3323	>
3324	>	public final boolean hasNext() { return next != null; }
3325	>	public final boolean hasMoreElements() { return next != null; }
3326
3327		public final void remove() {
3328	<	if (lastReturned == null)
3328	>	Node<K,V> p;
3329	>	if ((p = lastReturned) == null)
3330		throw new IllegalStateException();
1261	–	ConcurrentHashMap.this.remove(lastReturned.key);
3331		lastReturned = null;
3332	+	map.replaceNode(p.key, null, null);
3333		}
3334		}
3335
3336	<	final class KeyIterator
3337	<	extends HashIterator
3338	<	implements Iterator<K>, Enumeration<K>
3339	<	{
3340	<	public final K next()        { return super.nextEntry().key; }
3341	<	public final K nextElement() { return super.nextEntry().key; }
3336	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
3337	>	implements Iterator<K>, Enumeration<K> {
3338	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
3339	>	ConcurrentHashMap<K,V> map) {
3340	>	super(tab, index, size, limit, map);
3341	>	}
3342	>
3343	>	public final K next() {
3344	>	Node<K,V> p;
3345	>	if ((p = next) == null)
3346	>	throw new NoSuchElementException();
3347	>	K k = p.key;
3348	>	lastReturned = p;
3349	>	advance();
3350	>	return k;
3351	>	}
3352	>
3353	>	public final K nextElement() { return next(); }
3354		}
3355
3356	<	final class ValueIterator
3357	<	extends HashIterator
3358	<	implements Iterator<V>, Enumeration<V>
3359	<	{
3360	<	public final V next()        { return super.nextEntry().value; }
3361	<	public final V nextElement() { return super.nextEntry().value; }
3356	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
3357	>	implements Iterator<V>, Enumeration<V> {
3358	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
3359	>	ConcurrentHashMap<K,V> map) {
3360	>	super(tab, index, size, limit, map);
3361	>	}
3362	>
3363	>	public final V next() {
3364	>	Node<K,V> p;
3365	>	if ((p = next) == null)
3366	>	throw new NoSuchElementException();
3367	>	V v = p.val;
3368	>	lastReturned = p;
3369	>	advance();
3370	>	return v;
3371	>	}
3372	>
3373	>	public final V nextElement() { return next(); }
3374	>	}
3375	>
3376	>	static final class EntryIterator<K,V> extends BaseIterator<K,V>
3377	>	implements Iterator<Map.Entry<K,V>> {
3378	>	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
3379	>	ConcurrentHashMap<K,V> map) {
3380	>	super(tab, index, size, limit, map);
3381	>	}
3382	>
3383	>	public final Map.Entry<K,V> next() {
3384	>	Node<K,V> p;
3385	>	if ((p = next) == null)
3386	>	throw new NoSuchElementException();
3387	>	K k = p.key;
3388	>	V v = p.val;
3389	>	lastReturned = p;
3390	>	advance();
3391	>	return new MapEntry<K,V>(k, v, map);
3392	>	}
3393		}
3394
3395		/**
3396	<	* Custom Entry class used by EntryIterator.next(), that relays
1284	<	* setValue changes to the underlying map.
3396	>	* Exported Entry for EntryIterator
3397		*/
3398	<	final class WriteThroughEntry
3399	<	extends AbstractMap.SimpleEntry<K,V>
3400	<	{
3401	<	static final long serialVersionUID = 7249069246763182397L;
3402	<
3403	<	WriteThroughEntry(K k, V v) {
3404	<	super(k,v);
3398	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
3399	>	final K key; // non-null
3400	>	V val;       // non-null
3401	>	final ConcurrentHashMap<K,V> map;
3402	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
3403	>	this.key = key;
3404	>	this.val = val;
3405	>	this.map = map;
3406	>	}
3407	>	public K getKey()        { return key; }
3408	>	public V getValue()      { return val; }
3409	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
3410	>	public String toString() { return key + "=" + val; }
3411	>
3412	>	public boolean equals(Object o) {
3413	>	Object k, v; Map.Entry<?,?> e;
3414	>	return ((o instanceof Map.Entry) &&
3415	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3416	>	(v = e.getValue()) != null &&
3417	>	(k == key || k.equals(key)) &&
3418	>	(v == val || v.equals(val)));
3419		}
3420
3421		/**
3422		* Sets our entry's value and writes through to the map. The
3423	<	* value to return is somewhat arbitrary here. Since a
3424	<	* WriteThroughEntry does not necessarily track asynchronous
3425	<	* changes, the most recent "previous" value could be
3426	<	* different from what we return (or could even have been
3427	<	* removed in which case the put will re-establish). We do not
1302	<	* and cannot guarantee more.
3423	>	* value to return is somewhat arbitrary here. Since we do not
3424	>	* necessarily track asynchronous changes, the most recent
3425	>	* "previous" value could be different from what we return (or
3426	>	* could even have been removed, in which case the put will
3427	>	* re-establish). We do not and cannot guarantee more.
3428		*/
3429		public V setValue(V value) {
3430		if (value == null) throw new NullPointerException();
3431	<	V v = super.setValue(value);
3432	<	ConcurrentHashMap.this.put(getKey(), value);
3431	>	V v = val;
3432	>	val = value;
3433	>	map.put(key, value);
3434		return v;
3435		}
3436		}
3437
3438	<	final class EntryIterator
3439	<	extends HashIterator
3440	<	implements Iterator<Entry<K,V>>
3441	<	{
3442	<	public Map.Entry<K,V> next() {
3443	<	HashEntry<K,V> e = super.nextEntry();
3444	<	return new WriteThroughEntry(e.key, e.value);
3438	>	static final class KeySpliterator<K,V> extends Traverser<K,V>
3439	>	implements Spliterator<K> {
3440	>	long est;               // size estimate
3441	>	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3442	>	long est) {
3443	>	super(tab, size, index, limit);
3444	>	this.est = est;
3445	>	}
3446	>
3447	>	public Spliterator<K> trySplit() {
3448	>	int i, f, h;
3449	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3450	>	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
3451	>	f, est >>>= 1);
3452	>	}
3453	>
3454	>	public void forEachRemaining(Consumer<? super K> action) {
3455	>	if (action == null) throw new NullPointerException();
3456	>	for (Node<K,V> p; (p = advance()) != null;)
3457	>	action.accept(p.key);
3458	>	}
3459	>
3460	>	public boolean tryAdvance(Consumer<? super K> action) {
3461	>	if (action == null) throw new NullPointerException();
3462	>	Node<K,V> p;
3463	>	if ((p = advance()) == null)
3464	>	return false;
3465	>	action.accept(p.key);
3466	>	return true;
3467	>	}
3468	>
3469	>	public long estimateSize() { return est; }
3470	>
3471	>	public int characteristics() {
3472	>	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3473	>	Spliterator.NONNULL;
3474		}
3475		}
3476
3477	<	final class KeySet extends AbstractSet<K> {
3478	<	public Iterator<K> iterator() {
3479	<	return new KeyIterator();
3477	>	static final class ValueSpliterator<K,V> extends Traverser<K,V>
3478	>	implements Spliterator<V> {
3479	>	long est;               // size estimate
3480	>	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
3481	>	long est) {
3482	>	super(tab, size, index, limit);
3483	>	this.est = est;
3484	>	}
3485	>
3486	>	public Spliterator<V> trySplit() {
3487	>	int i, f, h;
3488	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3489	>	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
3490	>	f, est >>>= 1);
3491		}
3492	<	public int size() {
3493	<	return ConcurrentHashMap.this.size();
3492	>
3493	>	public void forEachRemaining(Consumer<? super V> action) {
3494	>	if (action == null) throw new NullPointerException();
3495	>	for (Node<K,V> p; (p = advance()) != null;)
3496	>	action.accept(p.val);
3497		}
3498	<	public boolean isEmpty() {
3499	<	return ConcurrentHashMap.this.isEmpty();
3498	>
3499	>	public boolean tryAdvance(Consumer<? super V> action) {
3500	>	if (action == null) throw new NullPointerException();
3501	>	Node<K,V> p;
3502	>	if ((p = advance()) == null)
3503	>	return false;
3504	>	action.accept(p.val);
3505	>	return true;
3506		}
3507	<	public boolean contains(Object o) {
3508	<	return ConcurrentHashMap.this.containsKey(o);
3507	>
3508	>	public long estimateSize() { return est; }
3509	>
3510	>	public int characteristics() {
3511	>	return Spliterator.CONCURRENT | Spliterator.NONNULL;
3512		}
3513	<	public boolean remove(Object o) {
3514	<	return ConcurrentHashMap.this.remove(o) != null;
3513	>	}
3514	>
3515	>	static final class EntrySpliterator<K,V> extends Traverser<K,V>
3516	>	implements Spliterator<Map.Entry<K,V>> {
3517	>	final ConcurrentHashMap<K,V> map; // To export MapEntry
3518	>	long est;               // size estimate
3519	>	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
3520	>	long est, ConcurrentHashMap<K,V> map) {
3521	>	super(tab, size, index, limit);
3522	>	this.map = map;
3523	>	this.est = est;
3524		}
3525	<	public void clear() {
3526	<	ConcurrentHashMap.this.clear();
3525	>
3526	>	public Spliterator<Map.Entry<K,V>> trySplit() {
3527	>	int i, f, h;
3528	>	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
3529	>	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
3530	>	f, est >>>= 1, map);
3531		}
3532	+
3533	+	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
3534	+	if (action == null) throw new NullPointerException();
3535	+	for (Node<K,V> p; (p = advance()) != null; )
3536	+	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3537	+	}
3538	+
3539	+	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
3540	+	if (action == null) throw new NullPointerException();
3541	+	Node<K,V> p;
3542	+	if ((p = advance()) == null)
3543	+	return false;
3544	+	action.accept(new MapEntry<K,V>(p.key, p.val, map));
3545	+	return true;
3546	+	}
3547	+
3548	+	public long estimateSize() { return est; }
3549	+
3550	+	public int characteristics() {
3551	+	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
3552	+	Spliterator.NONNULL;
3553	+	}
3554	+	}
3555	+
3556	+	// Parallel bulk operations
3557	+
3558	+	/**
3559	+	* Computes initial batch value for bulk tasks. The returned value
3560	+	* is approximately exp2 of the number of times (minus one) to
3561	+	* split task by two before executing leaf action. This value is
3562	+	* faster to compute and more convenient to use as a guide to
3563	+	* splitting than is the depth, since it is used while dividing by
3564	+	* two anyway.
3565	+	*/
3566	+	final int batchFor(long b) {
3567	+	long n;
3568	+	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3569	+	return 0;
3570	+	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3571	+	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3572		}
3573
3574	<	final class Values extends AbstractCollection<V> {
3575	<	public Iterator<V> iterator() {
3576	<	return new ValueIterator();
3574	>	/**
3575	>	* Performs the given action for each (key, value).
3576	>	*
3577	>	* @param parallelismThreshold the (estimated) number of elements
3578	>	* needed for this operation to be executed in parallel
3579	>	* @param action the action
3580	>	* @since 1.8
3581	>	*/
3582	>	public void forEach(long parallelismThreshold,
3583	>	BiConsumer<? super K,? super V> action) {
3584	>	if (action == null) throw new NullPointerException();
3585	>	new ForEachMappingTask<K,V>
3586	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3587	>	action).invoke();
3588	>	}
3589	>
3590	>	/**
3591	>	* Performs the given action for each non-null transformation
3592	>	* of each (key, value).
3593	>	*
3594	>	* @param parallelismThreshold the (estimated) number of elements
3595	>	* needed for this operation to be executed in parallel
3596	>	* @param transformer a function returning the transformation
3597	>	* for an element, or null if there is no transformation (in
3598	>	* which case the action is not applied)
3599	>	* @param action the action
3600	>	* @param <U> the return type of the transformer
3601	>	* @since 1.8
3602	>	*/
3603	>	public <U> void forEach(long parallelismThreshold,
3604	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3605	>	Consumer<? super U> action) {
3606	>	if (transformer == null || action == null)
3607	>	throw new NullPointerException();
3608	>	new ForEachTransformedMappingTask<K,V,U>
3609	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3610	>	transformer, action).invoke();
3611	>	}
3612	>
3613	>	/**
3614	>	* Returns a non-null result from applying the given search
3615	>	* function on each (key, value), or null if none.  Upon
3616	>	* success, further element processing is suppressed and the
3617	>	* results of any other parallel invocations of the search
3618	>	* function are ignored.
3619	>	*
3620	>	* @param parallelismThreshold the (estimated) number of elements
3621	>	* needed for this operation to be executed in parallel
3622	>	* @param searchFunction a function returning a non-null
3623	>	* result on success, else null
3624	>	* @param <U> the return type of the search function
3625	>	* @return a non-null result from applying the given search
3626	>	* function on each (key, value), or null if none
3627	>	* @since 1.8
3628	>	*/
3629	>	public <U> U search(long parallelismThreshold,
3630	>	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3631	>	if (searchFunction == null) throw new NullPointerException();
3632	>	return new SearchMappingsTask<K,V,U>
3633	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3634	>	searchFunction, new AtomicReference<U>()).invoke();
3635	>	}
3636	>
3637	>	/**
3638	>	* Returns the result of accumulating the given transformation
3639	>	* of all (key, value) pairs using the given reducer to
3640	>	* combine values, or null if none.
3641	>	*
3642	>	* @param parallelismThreshold the (estimated) number of elements
3643	>	* needed for this operation to be executed in parallel
3644	>	* @param transformer a function returning the transformation
3645	>	* for an element, or null if there is no transformation (in
3646	>	* which case it is not combined)
3647	>	* @param reducer a commutative associative combining function
3648	>	* @param <U> the return type of the transformer
3649	>	* @return the result of accumulating the given transformation
3650	>	* of all (key, value) pairs
3651	>	* @since 1.8
3652	>	*/
3653	>	public <U> U reduce(long parallelismThreshold,
3654	>	BiFunction<? super K, ? super V, ? extends U> transformer,
3655	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3656	>	if (transformer == null || reducer == null)
3657	>	throw new NullPointerException();
3658	>	return new MapReduceMappingsTask<K,V,U>
3659	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3660	>	null, transformer, reducer).invoke();
3661	>	}
3662	>
3663	>	/**
3664	>	* Returns the result of accumulating the given transformation
3665	>	* of all (key, value) pairs using the given reducer to
3666	>	* combine values, and the given basis as an identity value.
3667	>	*
3668	>	* @param parallelismThreshold the (estimated) number of elements
3669	>	* needed for this operation to be executed in parallel
3670	>	* @param transformer a function returning the transformation
3671	>	* for an element
3672	>	* @param basis the identity (initial default value) for the reduction
3673	>	* @param reducer a commutative associative combining function
3674	>	* @return the result of accumulating the given transformation
3675	>	* of all (key, value) pairs
3676	>	* @since 1.8
3677	>	*/
3678	>	public double reduceToDouble(long parallelismThreshold,
3679	>	ToDoubleBiFunction<? super K, ? super V> transformer,
3680	>	double basis,
3681	>	DoubleBinaryOperator reducer) {
3682	>	if (transformer == null || reducer == null)
3683	>	throw new NullPointerException();
3684	>	return new MapReduceMappingsToDoubleTask<K,V>
3685	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3686	>	null, transformer, basis, reducer).invoke();
3687	>	}
3688	>
3689	>	/**
3690	>	* Returns the result of accumulating the given transformation
3691	>	* of all (key, value) pairs using the given reducer to
3692	>	* combine values, and the given basis as an identity value.
3693	>	*
3694	>	* @param parallelismThreshold the (estimated) number of elements
3695	>	* needed for this operation to be executed in parallel
3696	>	* @param transformer a function returning the transformation
3697	>	* for an element
3698	>	* @param basis the identity (initial default value) for the reduction
3699	>	* @param reducer a commutative associative combining function
3700	>	* @return the result of accumulating the given transformation
3701	>	* of all (key, value) pairs
3702	>	* @since 1.8
3703	>	*/
3704	>	public long reduceToLong(long parallelismThreshold,
3705	>	ToLongBiFunction<? super K, ? super V> transformer,
3706	>	long basis,
3707	>	LongBinaryOperator reducer) {
3708	>	if (transformer == null || reducer == null)
3709	>	throw new NullPointerException();
3710	>	return new MapReduceMappingsToLongTask<K,V>
3711	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3712	>	null, transformer, basis, reducer).invoke();
3713	>	}
3714	>
3715	>	/**
3716	>	* Returns the result of accumulating the given transformation
3717	>	* of all (key, value) pairs using the given reducer to
3718	>	* combine values, and the given basis as an identity value.
3719	>	*
3720	>	* @param parallelismThreshold the (estimated) number of elements
3721	>	* needed for this operation to be executed in parallel
3722	>	* @param transformer a function returning the transformation
3723	>	* for an element
3724	>	* @param basis the identity (initial default value) for the reduction
3725	>	* @param reducer a commutative associative combining function
3726	>	* @return the result of accumulating the given transformation
3727	>	* of all (key, value) pairs
3728	>	* @since 1.8
3729	>	*/
3730	>	public int reduceToInt(long parallelismThreshold,
3731	>	ToIntBiFunction<? super K, ? super V> transformer,
3732	>	int basis,
3733	>	IntBinaryOperator reducer) {
3734	>	if (transformer == null || reducer == null)
3735	>	throw new NullPointerException();
3736	>	return new MapReduceMappingsToIntTask<K,V>
3737	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3738	>	null, transformer, basis, reducer).invoke();
3739	>	}
3740	>
3741	>	/**
3742	>	* Performs the given action for each key.
3743	>	*
3744	>	* @param parallelismThreshold the (estimated) number of elements
3745	>	* needed for this operation to be executed in parallel
3746	>	* @param action the action
3747	>	* @since 1.8
3748	>	*/
3749	>	public void forEachKey(long parallelismThreshold,
3750	>	Consumer<? super K> action) {
3751	>	if (action == null) throw new NullPointerException();
3752	>	new ForEachKeyTask<K,V>
3753	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3754	>	action).invoke();
3755	>	}
3756	>
3757	>	/**
3758	>	* Performs the given action for each non-null transformation
3759	>	* of each key.
3760	>	*
3761	>	* @param parallelismThreshold the (estimated) number of elements
3762	>	* needed for this operation to be executed in parallel
3763	>	* @param transformer a function returning the transformation
3764	>	* for an element, or null if there is no transformation (in
3765	>	* which case the action is not applied)
3766	>	* @param action the action
3767	>	* @param <U> the return type of the transformer
3768	>	* @since 1.8
3769	>	*/
3770	>	public <U> void forEachKey(long parallelismThreshold,
3771	>	Function<? super K, ? extends U> transformer,
3772	>	Consumer<? super U> action) {
3773	>	if (transformer == null || action == null)
3774	>	throw new NullPointerException();
3775	>	new ForEachTransformedKeyTask<K,V,U>
3776	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3777	>	transformer, action).invoke();
3778	>	}
3779	>
3780	>	/**
3781	>	* Returns a non-null result from applying the given search
3782	>	* function on each key, or null if none. Upon success,
3783	>	* further element processing is suppressed and the results of
3784	>	* any other parallel invocations of the search function are
3785	>	* ignored.
3786	>	*
3787	>	* @param parallelismThreshold the (estimated) number of elements
3788	>	* needed for this operation to be executed in parallel
3789	>	* @param searchFunction a function returning a non-null
3790	>	* result on success, else null
3791	>	* @param <U> the return type of the search function
3792	>	* @return a non-null result from applying the given search
3793	>	* function on each key, or null if none
3794	>	* @since 1.8
3795	>	*/
3796	>	public <U> U searchKeys(long parallelismThreshold,
3797	>	Function<? super K, ? extends U> searchFunction) {
3798	>	if (searchFunction == null) throw new NullPointerException();
3799	>	return new SearchKeysTask<K,V,U>
3800	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3801	>	searchFunction, new AtomicReference<U>()).invoke();
3802	>	}
3803	>
3804	>	/**
3805	>	* Returns the result of accumulating all keys using the given
3806	>	* reducer to combine values, or null if none.
3807	>	*
3808	>	* @param parallelismThreshold the (estimated) number of elements
3809	>	* needed for this operation to be executed in parallel
3810	>	* @param reducer a commutative associative combining function
3811	>	* @return the result of accumulating all keys using the given
3812	>	* reducer to combine values, or null if none
3813	>	* @since 1.8
3814	>	*/
3815	>	public K reduceKeys(long parallelismThreshold,
3816	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
3817	>	if (reducer == null) throw new NullPointerException();
3818	>	return new ReduceKeysTask<K,V>
3819	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3820	>	null, reducer).invoke();
3821	>	}
3822	>
3823	>	/**
3824	>	* Returns the result of accumulating the given transformation
3825	>	* of all keys using the given reducer to combine values, or
3826	>	* null if none.
3827	>	*
3828	>	* @param parallelismThreshold the (estimated) number of elements
3829	>	* needed for this operation to be executed in parallel
3830	>	* @param transformer a function returning the transformation
3831	>	* for an element, or null if there is no transformation (in
3832	>	* which case it is not combined)
3833	>	* @param reducer a commutative associative combining function
3834	>	* @param <U> the return type of the transformer
3835	>	* @return the result of accumulating the given transformation
3836	>	* of all keys
3837	>	* @since 1.8
3838	>	*/
3839	>	public <U> U reduceKeys(long parallelismThreshold,
3840	>	Function<? super K, ? extends U> transformer,
3841	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
3842	>	if (transformer == null || reducer == null)
3843	>	throw new NullPointerException();
3844	>	return new MapReduceKeysTask<K,V,U>
3845	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3846	>	null, transformer, reducer).invoke();
3847	>	}
3848	>
3849	>	/**
3850	>	* Returns the result of accumulating the given transformation
3851	>	* of all keys using the given reducer to combine values, and
3852	>	* the given basis as an identity value.
3853	>	*
3854	>	* @param parallelismThreshold the (estimated) number of elements
3855	>	* needed for this operation to be executed in parallel
3856	>	* @param transformer a function returning the transformation
3857	>	* for an element
3858	>	* @param basis the identity (initial default value) for the reduction
3859	>	* @param reducer a commutative associative combining function
3860	>	* @return the result of accumulating the given transformation
3861	>	* of all keys
3862	>	* @since 1.8
3863	>	*/
3864	>	public double reduceKeysToDouble(long parallelismThreshold,
3865	>	ToDoubleFunction<? super K> transformer,
3866	>	double basis,
3867	>	DoubleBinaryOperator reducer) {
3868	>	if (transformer == null || reducer == null)
3869	>	throw new NullPointerException();
3870	>	return new MapReduceKeysToDoubleTask<K,V>
3871	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3872	>	null, transformer, basis, reducer).invoke();
3873	>	}
3874	>
3875	>	/**
3876	>	* Returns the result of accumulating the given transformation
3877	>	* of all keys using the given reducer to combine values, and
3878	>	* the given basis as an identity value.
3879	>	*
3880	>	* @param parallelismThreshold the (estimated) number of elements
3881	>	* needed for this operation to be executed in parallel
3882	>	* @param transformer a function returning the transformation
3883	>	* for an element
3884	>	* @param basis the identity (initial default value) for the reduction
3885	>	* @param reducer a commutative associative combining function
3886	>	* @return the result of accumulating the given transformation
3887	>	* of all keys
3888	>	* @since 1.8
3889	>	*/
3890	>	public long reduceKeysToLong(long parallelismThreshold,
3891	>	ToLongFunction<? super K> transformer,
3892	>	long basis,
3893	>	LongBinaryOperator reducer) {
3894	>	if (transformer == null || reducer == null)
3895	>	throw new NullPointerException();
3896	>	return new MapReduceKeysToLongTask<K,V>
3897	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3898	>	null, transformer, basis, reducer).invoke();
3899	>	}
3900	>
3901	>	/**
3902	>	* Returns the result of accumulating the given transformation
3903	>	* of all keys using the given reducer to combine values, and
3904	>	* the given basis as an identity value.
3905	>	*
3906	>	* @param parallelismThreshold the (estimated) number of elements
3907	>	* needed for this operation to be executed in parallel
3908	>	* @param transformer a function returning the transformation
3909	>	* for an element
3910	>	* @param basis the identity (initial default value) for the reduction
3911	>	* @param reducer a commutative associative combining function
3912	>	* @return the result of accumulating the given transformation
3913	>	* of all keys
3914	>	* @since 1.8
3915	>	*/
3916	>	public int reduceKeysToInt(long parallelismThreshold,
3917	>	ToIntFunction<? super K> transformer,
3918	>	int basis,
3919	>	IntBinaryOperator reducer) {
3920	>	if (transformer == null || reducer == null)
3921	>	throw new NullPointerException();
3922	>	return new MapReduceKeysToIntTask<K,V>
3923	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3924	>	null, transformer, basis, reducer).invoke();
3925	>	}
3926	>
3927	>	/**
3928	>	* Performs the given action for each value.
3929	>	*
3930	>	* @param parallelismThreshold the (estimated) number of elements
3931	>	* needed for this operation to be executed in parallel
3932	>	* @param action the action
3933	>	* @since 1.8
3934	>	*/
3935	>	public void forEachValue(long parallelismThreshold,
3936	>	Consumer<? super V> action) {
3937	>	if (action == null)
3938	>	throw new NullPointerException();
3939	>	new ForEachValueTask<K,V>
3940	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3941	>	action).invoke();
3942	>	}
3943	>
3944	>	/**
3945	>	* Performs the given action for each non-null transformation
3946	>	* of each value.
3947	>	*
3948	>	* @param parallelismThreshold the (estimated) number of elements
3949	>	* needed for this operation to be executed in parallel
3950	>	* @param transformer a function returning the transformation
3951	>	* for an element, or null if there is no transformation (in
3952	>	* which case the action is not applied)
3953	>	* @param action the action
3954	>	* @param <U> the return type of the transformer
3955	>	* @since 1.8
3956	>	*/
3957	>	public <U> void forEachValue(long parallelismThreshold,
3958	>	Function<? super V, ? extends U> transformer,
3959	>	Consumer<? super U> action) {
3960	>	if (transformer == null || action == null)
3961	>	throw new NullPointerException();
3962	>	new ForEachTransformedValueTask<K,V,U>
3963	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3964	>	transformer, action).invoke();
3965	>	}
3966	>
3967	>	/**
3968	>	* Returns a non-null result from applying the given search
3969	>	* function on each value, or null if none.  Upon success,
3970	>	* further element processing is suppressed and the results of
3971	>	* any other parallel invocations of the search function are
3972	>	* ignored.
3973	>	*
3974	>	* @param parallelismThreshold the (estimated) number of elements
3975	>	* needed for this operation to be executed in parallel
3976	>	* @param searchFunction a function returning a non-null
3977	>	* result on success, else null
3978	>	* @param <U> the return type of the search function
3979	>	* @return a non-null result from applying the given search
3980	>	* function on each value, or null if none
3981	>	* @since 1.8
3982	>	*/
3983	>	public <U> U searchValues(long parallelismThreshold,
3984	>	Function<? super V, ? extends U> searchFunction) {
3985	>	if (searchFunction == null) throw new NullPointerException();
3986	>	return new SearchValuesTask<K,V,U>
3987	>	(null, batchFor(parallelismThreshold), 0, 0, table,
3988	>	searchFunction, new AtomicReference<U>()).invoke();
3989	>	}
3990	>
3991	>	/**
3992	>	* Returns the result of accumulating all values using the
3993	>	* given reducer to combine values, or null if none.
3994	>	*
3995	>	* @param parallelismThreshold the (estimated) number of elements
3996	>	* needed for this operation to be executed in parallel
3997	>	* @param reducer a commutative associative combining function
3998	>	* @return the result of accumulating all values
3999	>	* @since 1.8
4000	>	*/
4001	>	public V reduceValues(long parallelismThreshold,
4002	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4003	>	if (reducer == null) throw new NullPointerException();
4004	>	return new ReduceValuesTask<K,V>
4005	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4006	>	null, reducer).invoke();
4007	>	}
4008	>
4009	>	/**
4010	>	* Returns the result of accumulating the given transformation
4011	>	* of all values using the given reducer to combine values, or
4012	>	* null if none.
4013	>	*
4014	>	* @param parallelismThreshold the (estimated) number of elements
4015	>	* needed for this operation to be executed in parallel
4016	>	* @param transformer a function returning the transformation
4017	>	* for an element, or null if there is no transformation (in
4018	>	* which case it is not combined)
4019	>	* @param reducer a commutative associative combining function
4020	>	* @param <U> the return type of the transformer
4021	>	* @return the result of accumulating the given transformation
4022	>	* of all values
4023	>	* @since 1.8
4024	>	*/
4025	>	public <U> U reduceValues(long parallelismThreshold,
4026	>	Function<? super V, ? extends U> transformer,
4027	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4028	>	if (transformer == null || reducer == null)
4029	>	throw new NullPointerException();
4030	>	return new MapReduceValuesTask<K,V,U>
4031	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4032	>	null, transformer, reducer).invoke();
4033	>	}
4034	>
4035	>	/**
4036	>	* Returns the result of accumulating the given transformation
4037	>	* of all values using the given reducer to combine values,
4038	>	* and the given basis as an identity value.
4039	>	*
4040	>	* @param parallelismThreshold the (estimated) number of elements
4041	>	* needed for this operation to be executed in parallel
4042	>	* @param transformer a function returning the transformation
4043	>	* for an element
4044	>	* @param basis the identity (initial default value) for the reduction
4045	>	* @param reducer a commutative associative combining function
4046	>	* @return the result of accumulating the given transformation
4047	>	* of all values
4048	>	* @since 1.8
4049	>	*/
4050	>	public double reduceValuesToDouble(long parallelismThreshold,
4051	>	ToDoubleFunction<? super V> transformer,
4052	>	double basis,
4053	>	DoubleBinaryOperator reducer) {
4054	>	if (transformer == null || reducer == null)
4055	>	throw new NullPointerException();
4056	>	return new MapReduceValuesToDoubleTask<K,V>
4057	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4058	>	null, transformer, basis, reducer).invoke();
4059	>	}
4060	>
4061	>	/**
4062	>	* Returns the result of accumulating the given transformation
4063	>	* of all values using the given reducer to combine values,
4064	>	* and the given basis as an identity value.
4065	>	*
4066	>	* @param parallelismThreshold the (estimated) number of elements
4067	>	* needed for this operation to be executed in parallel
4068	>	* @param transformer a function returning the transformation
4069	>	* for an element
4070	>	* @param basis the identity (initial default value) for the reduction
4071	>	* @param reducer a commutative associative combining function
4072	>	* @return the result of accumulating the given transformation
4073	>	* of all values
4074	>	* @since 1.8
4075	>	*/
4076	>	public long reduceValuesToLong(long parallelismThreshold,
4077	>	ToLongFunction<? super V> transformer,
4078	>	long basis,
4079	>	LongBinaryOperator reducer) {
4080	>	if (transformer == null || reducer == null)
4081	>	throw new NullPointerException();
4082	>	return new MapReduceValuesToLongTask<K,V>
4083	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4084	>	null, transformer, basis, reducer).invoke();
4085	>	}
4086	>
4087	>	/**
4088	>	* Returns the result of accumulating the given transformation
4089	>	* of all values using the given reducer to combine values,
4090	>	* and the given basis as an identity value.
4091	>	*
4092	>	* @param parallelismThreshold the (estimated) number of elements
4093	>	* needed for this operation to be executed in parallel
4094	>	* @param transformer a function returning the transformation
4095	>	* for an element
4096	>	* @param basis the identity (initial default value) for the reduction
4097	>	* @param reducer a commutative associative combining function
4098	>	* @return the result of accumulating the given transformation
4099	>	* of all values
4100	>	* @since 1.8
4101	>	*/
4102	>	public int reduceValuesToInt(long parallelismThreshold,
4103	>	ToIntFunction<? super V> transformer,
4104	>	int basis,
4105	>	IntBinaryOperator reducer) {
4106	>	if (transformer == null || reducer == null)
4107	>	throw new NullPointerException();
4108	>	return new MapReduceValuesToIntTask<K,V>
4109	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4110	>	null, transformer, basis, reducer).invoke();
4111	>	}
4112	>
4113	>	/**
4114	>	* Performs the given action for each entry.
4115	>	*
4116	>	* @param parallelismThreshold the (estimated) number of elements
4117	>	* needed for this operation to be executed in parallel
4118	>	* @param action the action
4119	>	* @since 1.8
4120	>	*/
4121	>	public void forEachEntry(long parallelismThreshold,
4122	>	Consumer<? super Map.Entry<K,V>> action) {
4123	>	if (action == null) throw new NullPointerException();
4124	>	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
4125	>	action).invoke();
4126	>	}
4127	>
4128	>	/**
4129	>	* Performs the given action for each non-null transformation
4130	>	* of each entry.
4131	>	*
4132	>	* @param parallelismThreshold the (estimated) number of elements
4133	>	* needed for this operation to be executed in parallel
4134	>	* @param transformer a function returning the transformation
4135	>	* for an element, or null if there is no transformation (in
4136	>	* which case the action is not applied)
4137	>	* @param action the action
4138	>	* @param <U> the return type of the transformer
4139	>	* @since 1.8
4140	>	*/
4141	>	public <U> void forEachEntry(long parallelismThreshold,
4142	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4143	>	Consumer<? super U> action) {
4144	>	if (transformer == null || action == null)
4145	>	throw new NullPointerException();
4146	>	new ForEachTransformedEntryTask<K,V,U>
4147	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4148	>	transformer, action).invoke();
4149	>	}
4150	>
4151	>	/**
4152	>	* Returns a non-null result from applying the given search
4153	>	* function on each entry, or null if none.  Upon success,
4154	>	* further element processing is suppressed and the results of
4155	>	* any other parallel invocations of the search function are
4156	>	* ignored.
4157	>	*
4158	>	* @param parallelismThreshold the (estimated) number of elements
4159	>	* needed for this operation to be executed in parallel
4160	>	* @param searchFunction a function returning a non-null
4161	>	* result on success, else null
4162	>	* @param <U> the return type of the search function
4163	>	* @return a non-null result from applying the given search
4164	>	* function on each entry, or null if none
4165	>	* @since 1.8
4166	>	*/
4167	>	public <U> U searchEntries(long parallelismThreshold,
4168	>	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
4169	>	if (searchFunction == null) throw new NullPointerException();
4170	>	return new SearchEntriesTask<K,V,U>
4171	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4172	>	searchFunction, new AtomicReference<U>()).invoke();
4173	>	}
4174	>
4175	>	/**
4176	>	* Returns the result of accumulating all entries using the
4177	>	* given reducer to combine values, or null if none.
4178	>	*
4179	>	* @param parallelismThreshold the (estimated) number of elements
4180	>	* needed for this operation to be executed in parallel
4181	>	* @param reducer a commutative associative combining function
4182	>	* @return the result of accumulating all entries
4183	>	* @since 1.8
4184	>	*/
4185	>	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
4186	>	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4187	>	if (reducer == null) throw new NullPointerException();
4188	>	return new ReduceEntriesTask<K,V>
4189	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4190	>	null, reducer).invoke();
4191	>	}
4192	>
4193	>	/**
4194	>	* Returns the result of accumulating the given transformation
4195	>	* of all entries using the given reducer to combine values,
4196	>	* or null if none.
4197	>	*
4198	>	* @param parallelismThreshold the (estimated) number of elements
4199	>	* needed for this operation to be executed in parallel
4200	>	* @param transformer a function returning the transformation
4201	>	* for an element, or null if there is no transformation (in
4202	>	* which case it is not combined)
4203	>	* @param reducer a commutative associative combining function
4204	>	* @param <U> the return type of the transformer
4205	>	* @return the result of accumulating the given transformation
4206	>	* of all entries
4207	>	* @since 1.8
4208	>	*/
4209	>	public <U> U reduceEntries(long parallelismThreshold,
4210	>	Function<Map.Entry<K,V>, ? extends U> transformer,
4211	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4212	>	if (transformer == null || reducer == null)
4213	>	throw new NullPointerException();
4214	>	return new MapReduceEntriesTask<K,V,U>
4215	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4216	>	null, transformer, reducer).invoke();
4217	>	}
4218	>
4219	>	/**
4220	>	* Returns the result of accumulating the given transformation
4221	>	* of all entries using the given reducer to combine values,
4222	>	* and the given basis as an identity value.
4223	>	*
4224	>	* @param parallelismThreshold the (estimated) number of elements
4225	>	* needed for this operation to be executed in parallel
4226	>	* @param transformer a function returning the transformation
4227	>	* for an element
4228	>	* @param basis the identity (initial default value) for the reduction
4229	>	* @param reducer a commutative associative combining function
4230	>	* @return the result of accumulating the given transformation
4231	>	* of all entries
4232	>	* @since 1.8
4233	>	*/
4234	>	public double reduceEntriesToDouble(long parallelismThreshold,
4235	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
4236	>	double basis,
4237	>	DoubleBinaryOperator reducer) {
4238	>	if (transformer == null || reducer == null)
4239	>	throw new NullPointerException();
4240	>	return new MapReduceEntriesToDoubleTask<K,V>
4241	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4242	>	null, transformer, basis, reducer).invoke();
4243	>	}
4244	>
4245	>	/**
4246	>	* Returns the result of accumulating the given transformation
4247	>	* of all entries using the given reducer to combine values,
4248	>	* and the given basis as an identity value.
4249	>	*
4250	>	* @param parallelismThreshold the (estimated) number of elements
4251	>	* needed for this operation to be executed in parallel
4252	>	* @param transformer a function returning the transformation
4253	>	* for an element
4254	>	* @param basis the identity (initial default value) for the reduction
4255	>	* @param reducer a commutative associative combining function
4256	>	* @return the result of accumulating the given transformation
4257	>	* of all entries
4258	>	* @since 1.8
4259	>	*/
4260	>	public long reduceEntriesToLong(long parallelismThreshold,
4261	>	ToLongFunction<Map.Entry<K,V>> transformer,
4262	>	long basis,
4263	>	LongBinaryOperator reducer) {
4264	>	if (transformer == null || reducer == null)
4265	>	throw new NullPointerException();
4266	>	return new MapReduceEntriesToLongTask<K,V>
4267	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4268	>	null, transformer, basis, reducer).invoke();
4269	>	}
4270	>
4271	>	/**
4272	>	* Returns the result of accumulating the given transformation
4273	>	* of all entries using the given reducer to combine values,
4274	>	* and the given basis as an identity value.
4275	>	*
4276	>	* @param parallelismThreshold the (estimated) number of elements
4277	>	* needed for this operation to be executed in parallel
4278	>	* @param transformer a function returning the transformation
4279	>	* for an element
4280	>	* @param basis the identity (initial default value) for the reduction
4281	>	* @param reducer a commutative associative combining function
4282	>	* @return the result of accumulating the given transformation
4283	>	* of all entries
4284	>	* @since 1.8
4285	>	*/
4286	>	public int reduceEntriesToInt(long parallelismThreshold,
4287	>	ToIntFunction<Map.Entry<K,V>> transformer,
4288	>	int basis,
4289	>	IntBinaryOperator reducer) {
4290	>	if (transformer == null || reducer == null)
4291	>	throw new NullPointerException();
4292	>	return new MapReduceEntriesToIntTask<K,V>
4293	>	(null, batchFor(parallelismThreshold), 0, 0, table,
4294	>	null, transformer, basis, reducer).invoke();
4295	>	}
4296	>
4297	>
4298	>	/* ----------------Views -------------- */
4299	>
4300	>	/**
4301	>	* Base class for views.
4302	>	*/
4303	>	abstract static class CollectionView<K,V,E>
4304	>	implements Collection<E>, java.io.Serializable {
4305	>	private static final long serialVersionUID = 7249069246763182397L;
4306	>	final ConcurrentHashMap<K,V> map;
4307	>	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
4308	>
4309	>	/**
4310	>	* Returns the map backing this view.
4311	>	*
4312	>	* @return the map backing this view
4313	>	*/
4314	>	public ConcurrentHashMap<K,V> getMap() { return map; }
4315	>
4316	>	/**
4317	>	* Removes all of the elements from this view, by removing all
4318	>	* the mappings from the map backing this view.
4319	>	*/
4320	>	public final void clear()      { map.clear(); }
4321	>	public final int size()        { return map.size(); }
4322	>	public final boolean isEmpty() { return map.isEmpty(); }
4323	>
4324	>	// implementations below rely on concrete classes supplying these
4325	>	// abstract methods
4326	>	/**
4327	>	* Returns an iterator over the elements in this collection.
4328	>	*
4329	>	* <p>The returned iterator is
4330	>	* <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>.
4331	>	*
4332	>	* @return an iterator over the elements in this collection
4333	>	*/
4334	>	public abstract Iterator<E> iterator();
4335	>	public abstract boolean contains(Object o);
4336	>	public abstract boolean remove(Object o);
4337	>
4338	>	private static final String oomeMsg = "Required array size too large";
4339	>
4340	>	public final Object[] toArray() {
4341	>	long sz = map.mappingCount();
4342	>	if (sz > MAX_ARRAY_SIZE)
4343	>	throw new OutOfMemoryError(oomeMsg);
4344	>	int n = (int)sz;
4345	>	Object[] r = new Object[n];
4346	>	int i = 0;
4347	>	for (E e : this) {
4348	>	if (i == n) {
4349	>	if (n >= MAX_ARRAY_SIZE)
4350	>	throw new OutOfMemoryError(oomeMsg);
4351	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4352	>	n = MAX_ARRAY_SIZE;
4353	>	else
4354	>	n += (n >>> 1) + 1;
4355	>	r = Arrays.copyOf(r, n);
4356	>	}
4357	>	r[i++] = e;
4358	>	}
4359	>	return (i == n) ? r : Arrays.copyOf(r, i);
4360		}
4361	<	public int size() {
4362	<	return ConcurrentHashMap.this.size();
4361	>
4362	>	@SuppressWarnings("unchecked")
4363	>	public final <T> T[] toArray(T[] a) {
4364	>	long sz = map.mappingCount();
4365	>	if (sz > MAX_ARRAY_SIZE)
4366	>	throw new OutOfMemoryError(oomeMsg);
4367	>	int m = (int)sz;
4368	>	T[] r = (a.length >= m) ? a :
4369	>	(T[])java.lang.reflect.Array
4370	>	.newInstance(a.getClass().getComponentType(), m);
4371	>	int n = r.length;
4372	>	int i = 0;
4373	>	for (E e : this) {
4374	>	if (i == n) {
4375	>	if (n >= MAX_ARRAY_SIZE)
4376	>	throw new OutOfMemoryError(oomeMsg);
4377	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4378	>	n = MAX_ARRAY_SIZE;
4379	>	else
4380	>	n += (n >>> 1) + 1;
4381	>	r = Arrays.copyOf(r, n);
4382	>	}
4383	>	r[i++] = (T)e;
4384	>	}
4385	>	if (a == r && i < n) {
4386	>	r[i] = null; // null-terminate
4387	>	return r;
4388	>	}
4389	>	return (i == n) ? r : Arrays.copyOf(r, i);
4390		}
4391	<	public boolean isEmpty() {
4392	<	return ConcurrentHashMap.this.isEmpty();
4391	>
4392	>	/**
4393	>	* Returns a string representation of this collection.
4394	>	* The string representation consists of the string representations
4395	>	* of the collection's elements in the order they are returned by
4396	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4397	>	* Adjacent elements are separated by the characters {@code ", "}
4398	>	* (comma and space).  Elements are converted to strings as by
4399	>	* {@link String#valueOf(Object)}.
4400	>	*
4401	>	* @return a string representation of this collection
4402	>	*/
4403	>	public final String toString() {
4404	>	StringBuilder sb = new StringBuilder();
4405	>	sb.append('[');
4406	>	Iterator<E> it = iterator();
4407	>	if (it.hasNext()) {
4408	>	for (;;) {
4409	>	Object e = it.next();
4410	>	sb.append(e == this ? "(this Collection)" : e);
4411	>	if (!it.hasNext())
4412	>	break;
4413	>	sb.append(',').append(' ');
4414	>	}
4415	>	}
4416	>	return sb.append(']').toString();
4417		}
4418	<	public boolean contains(Object o) {
4419	<	return ConcurrentHashMap.this.containsValue(o);
4418	>
4419	>	public final boolean containsAll(Collection<?> c) {
4420	>	if (c != this) {
4421	>	for (Object e : c) {
4422	>	if (e == null || !contains(e))
4423	>	return false;
4424	>	}
4425	>	}
4426	>	return true;
4427		}
4428	<	public void clear() {
4429	<	ConcurrentHashMap.this.clear();
4428	>
4429	>	public final boolean removeAll(Collection<?> c) {
4430	>	if (c == null) throw new NullPointerException();
4431	>	boolean modified = false;
4432	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4433	>	if (c.contains(it.next())) {
4434	>	it.remove();
4435	>	modified = true;
4436	>	}
4437	>	}
4438	>	return modified;
4439	>	}
4440	>
4441	>	public final boolean retainAll(Collection<?> c) {
4442	>	if (c == null) throw new NullPointerException();
4443	>	boolean modified = false;
4444	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4445	>	if (!c.contains(it.next())) {
4446	>	it.remove();
4447	>	modified = true;
4448	>	}
4449	>	}
4450	>	return modified;
4451		}
4452	+
4453		}
4454
4455	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4456	<	public Iterator<Map.Entry<K,V>> iterator() {
4457	<	return new EntryIterator();
4455	>	/**
4456	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4457	>	* which additions may optionally be enabled by mapping to a
4458	>	* common value.  This class cannot be directly instantiated.
4459	>	* See {@link #keySet() keySet()},
4460	>	* {@link #keySet(Object) keySet(V)},
4461	>	* {@link #newKeySet() newKeySet()},
4462	>	* {@link #newKeySet(int) newKeySet(int)}.
4463	>	*
4464	>	* @since 1.8
4465	>	*/
4466	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4467	>	implements Set<K>, java.io.Serializable {
4468	>	private static final long serialVersionUID = 7249069246763182397L;
4469	>	private final V value;
4470	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4471	>	super(map);
4472	>	this.value = value;
4473	>	}
4474	>
4475	>	/**
4476	>	* Returns the default mapped value for additions,
4477	>	* or {@code null} if additions are not supported.
4478	>	*
4479	>	* @return the default mapped value for additions, or {@code null}
4480	>	* if not supported
4481	>	*/
4482	>	public V getMappedValue() { return value; }
4483	>
4484	>	/**
4485	>	* {@inheritDoc}
4486	>	* @throws NullPointerException if the specified key is null
4487	>	*/
4488	>	public boolean contains(Object o) { return map.containsKey(o); }
4489	>
4490	>	/**
4491	>	* Removes the key from this map view, by removing the key (and its
4492	>	* corresponding value) from the backing map.  This method does
4493	>	* nothing if the key is not in the map.
4494	>	*
4495	>	* @param  o the key to be removed from the backing map
4496	>	* @return {@code true} if the backing map contained the specified key
4497	>	* @throws NullPointerException if the specified key is null
4498	>	*/
4499	>	public boolean remove(Object o) { return map.remove(o) != null; }
4500	>
4501	>	/**
4502	>	* @return an iterator over the keys of the backing map
4503	>	*/
4504	>	public Iterator<K> iterator() {
4505	>	Node<K,V>[] t;
4506	>	ConcurrentHashMap<K,V> m = map;
4507	>	int f = (t = m.table) == null ? 0 : t.length;
4508	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4509	>	}
4510	>
4511	>	/**
4512	>	* Adds the specified key to this set view by mapping the key to
4513	>	* the default mapped value in the backing map, if defined.
4514	>	*
4515	>	* @param e key to be added
4516	>	* @return {@code true} if this set changed as a result of the call
4517	>	* @throws NullPointerException if the specified key is null
4518	>	* @throws UnsupportedOperationException if no default mapped value
4519	>	* for additions was provided
4520	>	*/
4521	>	public boolean add(K e) {
4522	>	V v;
4523	>	if ((v = value) == null)
4524	>	throw new UnsupportedOperationException();
4525	>	return map.putVal(e, v, true) == null;
4526	>	}
4527	>
4528	>	/**
4529	>	* Adds all of the elements in the specified collection to this set,
4530	>	* as if by calling {@link #add} on each one.
4531	>	*
4532	>	* @param c the elements to be inserted into this set
4533	>	* @return {@code true} if this set changed as a result of the call
4534	>	* @throws NullPointerException if the collection or any of its
4535	>	* elements are {@code null}
4536	>	* @throws UnsupportedOperationException if no default mapped value
4537	>	* for additions was provided
4538	>	*/
4539	>	public boolean addAll(Collection<? extends K> c) {
4540	>	boolean added = false;
4541	>	V v;
4542	>	if ((v = value) == null)
4543	>	throw new UnsupportedOperationException();
4544	>	for (K e : c) {
4545	>	if (map.putVal(e, v, true) == null)
4546	>	added = true;
4547	>	}
4548	>	return added;
4549	>	}
4550	>
4551	>	public int hashCode() {
4552	>	int h = 0;
4553	>	for (K e : this)
4554	>	h += e.hashCode();
4555	>	return h;
4556	>	}
4557	>
4558	>	public boolean equals(Object o) {
4559	>	Set<?> c;
4560	>	return ((o instanceof Set) &&
4561	>	((c = (Set<?>)o) == this ||
4562	>	(containsAll(c) && c.containsAll(this))));
4563	>	}
4564	>
4565	>	public Spliterator<K> spliterator() {
4566	>	Node<K,V>[] t;
4567	>	ConcurrentHashMap<K,V> m = map;
4568	>	long n = m.sumCount();
4569	>	int f = (t = m.table) == null ? 0 : t.length;
4570	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4571	>	}
4572	>
4573	>	public void forEach(Consumer<? super K> action) {
4574	>	if (action == null) throw new NullPointerException();
4575	>	Node<K,V>[] t;
4576	>	if ((t = map.table) != null) {
4577	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4578	>	for (Node<K,V> p; (p = it.advance()) != null; )
4579	>	action.accept(p.key);
4580	>	}
4581	>	}
4582	>	}
4583	>
4584	>	/**
4585	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4586	>	* values, in which additions are disabled. This class cannot be
4587	>	* directly instantiated. See {@link #values()}.
4588	>	*/
4589	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4590	>	implements Collection<V>, java.io.Serializable {
4591	>	private static final long serialVersionUID = 2249069246763182397L;
4592	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4593	>	public final boolean contains(Object o) {
4594	>	return map.containsValue(o);
4595	>	}
4596	>
4597	>	public final boolean remove(Object o) {
4598	>	if (o != null) {
4599	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4600	>	if (o.equals(it.next())) {
4601	>	it.remove();
4602	>	return true;
4603	>	}
4604	>	}
4605	>	}
4606	>	return false;
4607	>	}
4608	>
4609	>	public final Iterator<V> iterator() {
4610	>	ConcurrentHashMap<K,V> m = map;
4611	>	Node<K,V>[] t;
4612	>	int f = (t = m.table) == null ? 0 : t.length;
4613	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4614	>	}
4615	>
4616	>	public final boolean add(V e) {
4617	>	throw new UnsupportedOperationException();
4618	>	}
4619	>	public final boolean addAll(Collection<? extends V> c) {
4620	>	throw new UnsupportedOperationException();
4621		}
4622	+
4623	+	public Spliterator<V> spliterator() {
4624	+	Node<K,V>[] t;
4625	+	ConcurrentHashMap<K,V> m = map;
4626	+	long n = m.sumCount();
4627	+	int f = (t = m.table) == null ? 0 : t.length;
4628	+	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4629	+	}
4630	+
4631	+	public void forEach(Consumer<? super V> action) {
4632	+	if (action == null) throw new NullPointerException();
4633	+	Node<K,V>[] t;
4634	+	if ((t = map.table) != null) {
4635	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4636	+	for (Node<K,V> p; (p = it.advance()) != null; )
4637	+	action.accept(p.val);
4638	+	}
4639	+	}
4640	+	}
4641	+
4642	+	/**
4643	+	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4644	+	* entries.  This class cannot be directly instantiated. See
4645	+	* {@link #entrySet()}.
4646	+	*/
4647	+	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4648	+	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4649	+	private static final long serialVersionUID = 2249069246763182397L;
4650	+	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4651	+
4652		public boolean contains(Object o) {
4653	<	if (!(o instanceof Map.Entry))
4654	<	return false;
4655	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4656	<	V v = ConcurrentHashMap.this.get(e.getKey());
4657	<	return v != null && v.equals(e.getValue());
4653	>	Object k, v, r; Map.Entry<?,?> e;
4654	>	return ((o instanceof Map.Entry) &&
4655	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4656	>	(r = map.get(k)) != null &&
4657	>	(v = e.getValue()) != null &&
4658	>	(v == r || v.equals(r)));
4659		}
4660	+
4661		public boolean remove(Object o) {
4662	<	if (!(o instanceof Map.Entry))
4663	<	return false;
4664	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4665	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
4662	>	Object k, v; Map.Entry<?,?> e;
4663	>	return ((o instanceof Map.Entry) &&
4664	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4665	>	(v = e.getValue()) != null &&
4666	>	map.remove(k, v));
4667		}
4668	<	public int size() {
4669	<	return ConcurrentHashMap.this.size();
4668	>
4669	>	/**
4670	>	* @return an iterator over the entries of the backing map
4671	>	*/
4672	>	public Iterator<Map.Entry<K,V>> iterator() {
4673	>	ConcurrentHashMap<K,V> m = map;
4674	>	Node<K,V>[] t;
4675	>	int f = (t = m.table) == null ? 0 : t.length;
4676	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4677	>	}
4678	>
4679	>	public boolean add(Entry<K,V> e) {
4680	>	return map.putVal(e.getKey(), e.getValue(), false) == null;
4681	>	}
4682	>
4683	>	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4684	>	boolean added = false;
4685	>	for (Entry<K,V> e : c) {
4686	>	if (add(e))
4687	>	added = true;
4688	>	}
4689	>	return added;
4690		}
4691	<	public boolean isEmpty() {
4692	<	return ConcurrentHashMap.this.isEmpty();
4691	>
4692	>	public final int hashCode() {
4693	>	int h = 0;
4694	>	Node<K,V>[] t;
4695	>	if ((t = map.table) != null) {
4696	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4697	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
4698	>	h += p.hashCode();
4699	>	}
4700	>	}
4701	>	return h;
4702		}
4703	<	public void clear() {
4704	<	ConcurrentHashMap.this.clear();
4703	>
4704	>	public final boolean equals(Object o) {
4705	>	Set<?> c;
4706	>	return ((o instanceof Set) &&
4707	>	((c = (Set<?>)o) == this ||
4708	>	(containsAll(c) && c.containsAll(this))));
4709	>	}
4710	>
4711	>	public Spliterator<Map.Entry<K,V>> spliterator() {
4712	>	Node<K,V>[] t;
4713	>	ConcurrentHashMap<K,V> m = map;
4714	>	long n = m.sumCount();
4715	>	int f = (t = m.table) == null ? 0 : t.length;
4716	>	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4717	>	}
4718	>
4719	>	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4720	>	if (action == null) throw new NullPointerException();
4721	>	Node<K,V>[] t;
4722	>	if ((t = map.table) != null) {
4723	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4724	>	for (Node<K,V> p; (p = it.advance()) != null; )
4725	>	action.accept(new MapEntry<K,V>(p.key, p.val, map));
4726	>	}
4727		}
4728	+
4729		}
4730
4731	<	/* ---------------- Serialization Support -------------- */
4731	>	// -------------------------------------------------------
4732
4733		/**
4734	<	* Saves the state of the <tt>ConcurrentHashMap</tt> instance to a
4735	<	* 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.
4734	>	* Base class for bulk tasks. Repeats some fields and code from
4735	>	* class Traverser, because we need to subclass CountedCompleter.
4736		*/
4737	<	private void writeObject(java.io.ObjectOutputStream s)
4738	<	throws java.io.IOException {
4739	<	// force all segments for serialization compatibility
4740	<	for (int k = 0; k < segments.length; ++k)
4741	<	ensureSegment(k);
4742	<	s.defaultWriteObject();
4743	<
4744	<	final Segment<K,V>[] segments = this.segments;
4745	<	for (int k = 0; k < segments.length; ++k) {
4746	<	Segment<K,V> seg = segmentAt(segments, k);
4747	<	seg.lock();
4748	<	try {
4749	<	HashEntry<K,V>[] tab = seg.table;
4750	<	for (int i = 0; i < tab.length; ++i) {
4751	<	HashEntry<K,V> e;
4752	<	for (e = entryAt(tab, i); e != null; e = e.next) {
4753	<	s.writeObject(e.key);
4754	<	s.writeObject(e.value);
4737	>	@SuppressWarnings("serial")
4738	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4739	>	Node<K,V>[] tab;        // same as Traverser
4740	>	Node<K,V> next;
4741	>	TableStack<K,V> stack, spare;
4742	>	int index;
4743	>	int baseIndex;
4744	>	int baseLimit;
4745	>	final int baseSize;
4746	>	int batch;              // split control
4747	>
4748	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4749	>	super(par);
4750	>	this.batch = b;
4751	>	this.index = this.baseIndex = i;
4752	>	if ((this.tab = t) == null)
4753	>	this.baseSize = this.baseLimit = 0;
4754	>	else if (par == null)
4755	>	this.baseSize = this.baseLimit = t.length;
4756	>	else {
4757	>	this.baseLimit = f;
4758	>	this.baseSize = par.baseSize;
4759	>	}
4760	>	}
4761	>
4762	>	/**
4763	>	* Same as Traverser version
4764	>	*/
4765	>	final Node<K,V> advance() {
4766	>	Node<K,V> e;
4767	>	if ((e = next) != null)
4768	>	e = e.next;
4769	>	for (;;) {
4770	>	Node<K,V>[] t; int i, n;
4771	>	if (e != null)
4772	>	return next = e;
4773	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4774	>	(n = t.length) <= (i = index) || i < 0)
4775	>	return next = null;
4776	>	if ((e = tabAt(t, i)) != null && e.hash < 0) {
4777	>	if (e instanceof ForwardingNode) {
4778	>	tab = ((ForwardingNode<K,V>)e).nextTable;
4779	>	e = null;
4780	>	pushState(t, i, n);
4781	>	continue;
4782		}
4783	+	else if (e instanceof TreeBin)
4784	+	e = ((TreeBin<K,V>)e).first;
4785	+	else
4786	+	e = null;
4787		}
4788	<	} finally {
4789	<	seg.unlock();
4788	>	if (stack != null)
4789	>	recoverState(n);
4790	>	else if ((index = i + baseSize) >= n)
4791	>	index = ++baseIndex;
4792		}
4793		}
4794	<	s.writeObject(null);
4795	<	s.writeObject(null);
4794	>
4795	>	private void pushState(Node<K,V>[] t, int i, int n) {
4796	>	TableStack<K,V> s = spare;
4797	>	if (s != null)
4798	>	spare = s.next;
4799	>	else
4800	>	s = new TableStack<K,V>();
4801	>	s.tab = t;
4802	>	s.length = n;
4803	>	s.index = i;
4804	>	s.next = stack;
4805	>	stack = s;
4806	>	}
4807	>
4808	>	private void recoverState(int n) {
4809	>	TableStack<K,V> s; int len;
4810	>	while ((s = stack) != null && (index += (len = s.length)) >= n) {
4811	>	n = len;
4812	>	index = s.index;
4813	>	tab = s.tab;
4814	>	s.tab = null;
4815	>	TableStack<K,V> next = s.next;
4816	>	s.next = spare; // save for reuse
4817	>	stack = next;
4818	>	spare = s;
4819	>	}
4820	>	if (s == null && (index += baseSize) >= n)
4821	>	index = ++baseIndex;
4822	>	}
4823		}
4824
4825	<	/**
4826	<	* Reconstitutes the <tt>ConcurrentHashMap</tt> instance from a
4827	<	* stream (i.e., deserializes it).
4828	<	* @param s the stream
4829	<	*/
4830	<	@SuppressWarnings("unchecked")
4831	<	private void readObject(java.io.ObjectInputStream s)
4832	<	throws java.io.IOException, ClassNotFoundException {
4833	<	s.defaultReadObject();
4825	>	/*
4826	>	* Task classes. Coded in a regular but ugly format/style to
4827	>	* simplify checks that each variant differs in the right way from
4828	>	* others. The null screenings exist because compilers cannot tell
4829	>	* that we've already null-checked task arguments, so we force
4830	>	* simplest hoisted bypass to help avoid convoluted traps.
4831	>	*/
4832	>	@SuppressWarnings("serial")
4833	>	static final class ForEachKeyTask<K,V>
4834	>	extends BulkTask<K,V,Void> {
4835	>	final Consumer<? super K> action;
4836	>	ForEachKeyTask
4837	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4838	>	Consumer<? super K> action) {
4839	>	super(p, b, i, f, t);
4840	>	this.action = action;
4841	>	}
4842	>	public final void compute() {
4843	>	final Consumer<? super K> action;
4844	>	if ((action = this.action) != null) {
4845	>	for (int i = baseIndex, f, h; batch > 0 &&
4846	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4847	>	addToPendingCount(1);
4848	>	new ForEachKeyTask<K,V>
4849	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4850	>	action).fork();
4851	>	}
4852	>	for (Node<K,V> p; (p = advance()) != null;)
4853	>	action.accept(p.key);
4854	>	propagateCompletion();
4855	>	}
4856	>	}
4857	>	}
4858
4859	<	// Re-initialize segments to be minimally sized, and let grow.
4860	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
4861	<	final Segment<K,V>[] segments = this.segments;
4862	<	for (int k = 0; k < segments.length; ++k) {
4863	<	Segment<K,V> seg = segments[k];
4864	<	if (seg != null) {
4865	<	seg.threshold = (int)(cap * seg.loadFactor);
4866	<	seg.table = (HashEntry<K,V>[]) new HashEntry<?,?>[cap];
4859	>	@SuppressWarnings("serial")
4860	>	static final class ForEachValueTask<K,V>
4861	>	extends BulkTask<K,V,Void> {
4862	>	final Consumer<? super V> action;
4863	>	ForEachValueTask
4864	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4865	>	Consumer<? super V> action) {
4866	>	super(p, b, i, f, t);
4867	>	this.action = action;
4868	>	}
4869	>	public final void compute() {
4870	>	final Consumer<? super V> action;
4871	>	if ((action = this.action) != null) {
4872	>	for (int i = baseIndex, f, h; batch > 0 &&
4873	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4874	>	addToPendingCount(1);
4875	>	new ForEachValueTask<K,V>
4876	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4877	>	action).fork();
4878	>	}
4879	>	for (Node<K,V> p; (p = advance()) != null;)
4880	>	action.accept(p.val);
4881	>	propagateCompletion();
4882		}
4883		}
4884	+	}
4885
4886	<	// Read the keys and values, and put the mappings in the table
4887	<	for (;;) {
4888	<	K key = (K) s.readObject();
4889	<	V value = (V) s.readObject();
4890	<	if (key == null)
4891	<	break;
4892	<	put(key, value);
4886	>	@SuppressWarnings("serial")
4887	>	static final class ForEachEntryTask<K,V>
4888	>	extends BulkTask<K,V,Void> {
4889	>	final Consumer<? super Entry<K,V>> action;
4890	>	ForEachEntryTask
4891	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4892	>	Consumer<? super Entry<K,V>> action) {
4893	>	super(p, b, i, f, t);
4894	>	this.action = action;
4895	>	}
4896	>	public final void compute() {
4897	>	final Consumer<? super Entry<K,V>> action;
4898	>	if ((action = this.action) != null) {
4899	>	for (int i = baseIndex, f, h; batch > 0 &&
4900	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4901	>	addToPendingCount(1);
4902	>	new ForEachEntryTask<K,V>
4903	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4904	>	action).fork();
4905	>	}
4906	>	for (Node<K,V> p; (p = advance()) != null; )
4907	>	action.accept(p);
4908	>	propagateCompletion();
4909	>	}
4910	>	}
4911	>	}
4912	>
4913	>	@SuppressWarnings("serial")
4914	>	static final class ForEachMappingTask<K,V>
4915	>	extends BulkTask<K,V,Void> {
4916	>	final BiConsumer<? super K, ? super V> action;
4917	>	ForEachMappingTask
4918	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4919	>	BiConsumer<? super K,? super V> action) {
4920	>	super(p, b, i, f, t);
4921	>	this.action = action;
4922	>	}
4923	>	public final void compute() {
4924	>	final BiConsumer<? super K, ? super V> action;
4925	>	if ((action = this.action) != null) {
4926	>	for (int i = baseIndex, f, h; batch > 0 &&
4927	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4928	>	addToPendingCount(1);
4929	>	new ForEachMappingTask<K,V>
4930	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4931	>	action).fork();
4932	>	}
4933	>	for (Node<K,V> p; (p = advance()) != null; )
4934	>	action.accept(p.key, p.val);
4935	>	propagateCompletion();
4936	>	}
4937	>	}
4938	>	}
4939	>
4940	>	@SuppressWarnings("serial")
4941	>	static final class ForEachTransformedKeyTask<K,V,U>
4942	>	extends BulkTask<K,V,Void> {
4943	>	final Function<? super K, ? extends U> transformer;
4944	>	final Consumer<? super U> action;
4945	>	ForEachTransformedKeyTask
4946	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4947	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
4948	>	super(p, b, i, f, t);
4949	>	this.transformer = transformer; this.action = action;
4950	>	}
4951	>	public final void compute() {
4952	>	final Function<? super K, ? extends U> transformer;
4953	>	final Consumer<? super U> action;
4954	>	if ((transformer = this.transformer) != null &&
4955	>	(action = this.action) != null) {
4956	>	for (int i = baseIndex, f, h; batch > 0 &&
4957	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4958	>	addToPendingCount(1);
4959	>	new ForEachTransformedKeyTask<K,V,U>
4960	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4961	>	transformer, action).fork();
4962	>	}
4963	>	for (Node<K,V> p; (p = advance()) != null; ) {
4964	>	U u;
4965	>	if ((u = transformer.apply(p.key)) != null)
4966	>	action.accept(u);
4967	>	}
4968	>	propagateCompletion();
4969	>	}
4970	>	}
4971	>	}
4972	>
4973	>	@SuppressWarnings("serial")
4974	>	static final class ForEachTransformedValueTask<K,V,U>
4975	>	extends BulkTask<K,V,Void> {
4976	>	final Function<? super V, ? extends U> transformer;
4977	>	final Consumer<? super U> action;
4978	>	ForEachTransformedValueTask
4979	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4980	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
4981	>	super(p, b, i, f, t);
4982	>	this.transformer = transformer; this.action = action;
4983	>	}
4984	>	public final void compute() {
4985	>	final Function<? super V, ? extends U> transformer;
4986	>	final Consumer<? super U> action;
4987	>	if ((transformer = this.transformer) != null &&
4988	>	(action = this.action) != null) {
4989	>	for (int i = baseIndex, f, h; batch > 0 &&
4990	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4991	>	addToPendingCount(1);
4992	>	new ForEachTransformedValueTask<K,V,U>
4993	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4994	>	transformer, action).fork();
4995	>	}
4996	>	for (Node<K,V> p; (p = advance()) != null; ) {
4997	>	U u;
4998	>	if ((u = transformer.apply(p.val)) != null)
4999	>	action.accept(u);
5000	>	}
5001	>	propagateCompletion();
5002	>	}
5003	>	}
5004	>	}
5005	>
5006	>	@SuppressWarnings("serial")
5007	>	static final class ForEachTransformedEntryTask<K,V,U>
5008	>	extends BulkTask<K,V,Void> {
5009	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5010	>	final Consumer<? super U> action;
5011	>	ForEachTransformedEntryTask
5012	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5013	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
5014	>	super(p, b, i, f, t);
5015	>	this.transformer = transformer; this.action = action;
5016	>	}
5017	>	public final void compute() {
5018	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5019	>	final Consumer<? super U> action;
5020	>	if ((transformer = this.transformer) != null &&
5021	>	(action = this.action) != null) {
5022	>	for (int i = baseIndex, f, h; batch > 0 &&
5023	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5024	>	addToPendingCount(1);
5025	>	new ForEachTransformedEntryTask<K,V,U>
5026	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5027	>	transformer, action).fork();
5028	>	}
5029	>	for (Node<K,V> p; (p = advance()) != null; ) {
5030	>	U u;
5031	>	if ((u = transformer.apply(p)) != null)
5032	>	action.accept(u);
5033	>	}
5034	>	propagateCompletion();
5035	>	}
5036	>	}
5037	>	}
5038	>
5039	>	@SuppressWarnings("serial")
5040	>	static final class ForEachTransformedMappingTask<K,V,U>
5041	>	extends BulkTask<K,V,Void> {
5042	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5043	>	final Consumer<? super U> action;
5044	>	ForEachTransformedMappingTask
5045	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5046	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5047	>	Consumer<? super U> action) {
5048	>	super(p, b, i, f, t);
5049	>	this.transformer = transformer; this.action = action;
5050	>	}
5051	>	public final void compute() {
5052	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5053	>	final Consumer<? super U> action;
5054	>	if ((transformer = this.transformer) != null &&
5055	>	(action = this.action) != null) {
5056	>	for (int i = baseIndex, f, h; batch > 0 &&
5057	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5058	>	addToPendingCount(1);
5059	>	new ForEachTransformedMappingTask<K,V,U>
5060	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5061	>	transformer, action).fork();
5062	>	}
5063	>	for (Node<K,V> p; (p = advance()) != null; ) {
5064	>	U u;
5065	>	if ((u = transformer.apply(p.key, p.val)) != null)
5066	>	action.accept(u);
5067	>	}
5068	>	propagateCompletion();
5069	>	}
5070	>	}
5071	>	}
5072	>
5073	>	@SuppressWarnings("serial")
5074	>	static final class SearchKeysTask<K,V,U>
5075	>	extends BulkTask<K,V,U> {
5076	>	final Function<? super K, ? extends U> searchFunction;
5077	>	final AtomicReference<U> result;
5078	>	SearchKeysTask
5079	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5080	>	Function<? super K, ? extends U> searchFunction,
5081	>	AtomicReference<U> result) {
5082	>	super(p, b, i, f, t);
5083	>	this.searchFunction = searchFunction; this.result = result;
5084	>	}
5085	>	public final U getRawResult() { return result.get(); }
5086	>	public final void compute() {
5087	>	final Function<? super K, ? extends U> searchFunction;
5088	>	final AtomicReference<U> result;
5089	>	if ((searchFunction = this.searchFunction) != null &&
5090	>	(result = this.result) != null) {
5091	>	for (int i = baseIndex, f, h; batch > 0 &&
5092	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5093	>	if (result.get() != null)
5094	>	return;
5095	>	addToPendingCount(1);
5096	>	new SearchKeysTask<K,V,U>
5097	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5098	>	searchFunction, result).fork();
5099	>	}
5100	>	while (result.get() == null) {
5101	>	U u;
5102	>	Node<K,V> p;
5103	>	if ((p = advance()) == null) {
5104	>	propagateCompletion();
5105	>	break;
5106	>	}
5107	>	if ((u = searchFunction.apply(p.key)) != null) {
5108	>	if (result.compareAndSet(null, u))
5109	>	quietlyCompleteRoot();
5110	>	break;
5111	>	}
5112	>	}
5113	>	}
5114	>	}
5115	>	}
5116	>
5117	>	@SuppressWarnings("serial")
5118	>	static final class SearchValuesTask<K,V,U>
5119	>	extends BulkTask<K,V,U> {
5120	>	final Function<? super V, ? extends U> searchFunction;
5121	>	final AtomicReference<U> result;
5122	>	SearchValuesTask
5123	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5124	>	Function<? super V, ? extends U> searchFunction,
5125	>	AtomicReference<U> result) {
5126	>	super(p, b, i, f, t);
5127	>	this.searchFunction = searchFunction; this.result = result;
5128	>	}
5129	>	public final U getRawResult() { return result.get(); }
5130	>	public final void compute() {
5131	>	final Function<? super V, ? extends U> searchFunction;
5132	>	final AtomicReference<U> result;
5133	>	if ((searchFunction = this.searchFunction) != null &&
5134	>	(result = this.result) != null) {
5135	>	for (int i = baseIndex, f, h; batch > 0 &&
5136	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5137	>	if (result.get() != null)
5138	>	return;
5139	>	addToPendingCount(1);
5140	>	new SearchValuesTask<K,V,U>
5141	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5142	>	searchFunction, result).fork();
5143	>	}
5144	>	while (result.get() == null) {
5145	>	U u;
5146	>	Node<K,V> p;
5147	>	if ((p = advance()) == null) {
5148	>	propagateCompletion();
5149	>	break;
5150	>	}
5151	>	if ((u = searchFunction.apply(p.val)) != null) {
5152	>	if (result.compareAndSet(null, u))
5153	>	quietlyCompleteRoot();
5154	>	break;
5155	>	}
5156	>	}
5157	>	}
5158	>	}
5159	>	}
5160	>
5161	>	@SuppressWarnings("serial")
5162	>	static final class SearchEntriesTask<K,V,U>
5163	>	extends BulkTask<K,V,U> {
5164	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5165	>	final AtomicReference<U> result;
5166	>	SearchEntriesTask
5167	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5168	>	Function<Entry<K,V>, ? extends U> searchFunction,
5169	>	AtomicReference<U> result) {
5170	>	super(p, b, i, f, t);
5171	>	this.searchFunction = searchFunction; this.result = result;
5172	>	}
5173	>	public final U getRawResult() { return result.get(); }
5174	>	public final void compute() {
5175	>	final Function<Entry<K,V>, ? extends U> searchFunction;
5176	>	final AtomicReference<U> result;
5177	>	if ((searchFunction = this.searchFunction) != null &&
5178	>	(result = this.result) != null) {
5179	>	for (int i = baseIndex, f, h; batch > 0 &&
5180	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5181	>	if (result.get() != null)
5182	>	return;
5183	>	addToPendingCount(1);
5184	>	new SearchEntriesTask<K,V,U>
5185	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5186	>	searchFunction, result).fork();
5187	>	}
5188	>	while (result.get() == null) {
5189	>	U u;
5190	>	Node<K,V> p;
5191	>	if ((p = advance()) == null) {
5192	>	propagateCompletion();
5193	>	break;
5194	>	}
5195	>	if ((u = searchFunction.apply(p)) != null) {
5196	>	if (result.compareAndSet(null, u))
5197	>	quietlyCompleteRoot();
5198	>	return;
5199	>	}
5200	>	}
5201	>	}
5202	>	}
5203	>	}
5204	>
5205	>	@SuppressWarnings("serial")
5206	>	static final class SearchMappingsTask<K,V,U>
5207	>	extends BulkTask<K,V,U> {
5208	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5209	>	final AtomicReference<U> result;
5210	>	SearchMappingsTask
5211	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5212	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
5213	>	AtomicReference<U> result) {
5214	>	super(p, b, i, f, t);
5215	>	this.searchFunction = searchFunction; this.result = result;
5216	>	}
5217	>	public final U getRawResult() { return result.get(); }
5218	>	public final void compute() {
5219	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
5220	>	final AtomicReference<U> result;
5221	>	if ((searchFunction = this.searchFunction) != null &&
5222	>	(result = this.result) != null) {
5223	>	for (int i = baseIndex, f, h; batch > 0 &&
5224	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5225	>	if (result.get() != null)
5226	>	return;
5227	>	addToPendingCount(1);
5228	>	new SearchMappingsTask<K,V,U>
5229	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5230	>	searchFunction, result).fork();
5231	>	}
5232	>	while (result.get() == null) {
5233	>	U u;
5234	>	Node<K,V> p;
5235	>	if ((p = advance()) == null) {
5236	>	propagateCompletion();
5237	>	break;
5238	>	}
5239	>	if ((u = searchFunction.apply(p.key, p.val)) != null) {
5240	>	if (result.compareAndSet(null, u))
5241	>	quietlyCompleteRoot();
5242	>	break;
5243	>	}
5244	>	}
5245	>	}
5246	>	}
5247	>	}
5248	>
5249	>	@SuppressWarnings("serial")
5250	>	static final class ReduceKeysTask<K,V>
5251	>	extends BulkTask<K,V,K> {
5252	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5253	>	K result;
5254	>	ReduceKeysTask<K,V> rights, nextRight;
5255	>	ReduceKeysTask
5256	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5257	>	ReduceKeysTask<K,V> nextRight,
5258	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
5259	>	super(p, b, i, f, t); this.nextRight = nextRight;
5260	>	this.reducer = reducer;
5261	>	}
5262	>	public final K getRawResult() { return result; }
5263	>	public final void compute() {
5264	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
5265	>	if ((reducer = this.reducer) != null) {
5266	>	for (int i = baseIndex, f, h; batch > 0 &&
5267	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5268	>	addToPendingCount(1);
5269	>	(rights = new ReduceKeysTask<K,V>
5270	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5271	>	rights, reducer)).fork();
5272	>	}
5273	>	K r = null;
5274	>	for (Node<K,V> p; (p = advance()) != null; ) {
5275	>	K u = p.key;
5276	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
5277	>	}
5278	>	result = r;
5279	>	CountedCompleter<?> c;
5280	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5281	>	@SuppressWarnings("unchecked")
5282	>	ReduceKeysTask<K,V>
5283	>	t = (ReduceKeysTask<K,V>)c,
5284	>	s = t.rights;
5285	>	while (s != null) {
5286	>	K tr, sr;
5287	>	if ((sr = s.result) != null)
5288	>	t.result = (((tr = t.result) == null) ? sr :
5289	>	reducer.apply(tr, sr));
5290	>	s = t.rights = s.nextRight;
5291	>	}
5292	>	}
5293	>	}
5294	>	}
5295	>	}
5296	>
5297	>	@SuppressWarnings("serial")
5298	>	static final class ReduceValuesTask<K,V>
5299	>	extends BulkTask<K,V,V> {
5300	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5301	>	V result;
5302	>	ReduceValuesTask<K,V> rights, nextRight;
5303	>	ReduceValuesTask
5304	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5305	>	ReduceValuesTask<K,V> nextRight,
5306	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
5307	>	super(p, b, i, f, t); this.nextRight = nextRight;
5308	>	this.reducer = reducer;
5309	>	}
5310	>	public final V getRawResult() { return result; }
5311	>	public final void compute() {
5312	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
5313	>	if ((reducer = this.reducer) != null) {
5314	>	for (int i = baseIndex, f, h; batch > 0 &&
5315	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5316	>	addToPendingCount(1);
5317	>	(rights = new ReduceValuesTask<K,V>
5318	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5319	>	rights, reducer)).fork();
5320	>	}
5321	>	V r = null;
5322	>	for (Node<K,V> p; (p = advance()) != null; ) {
5323	>	V v = p.val;
5324	>	r = (r == null) ? v : reducer.apply(r, v);
5325	>	}
5326	>	result = r;
5327	>	CountedCompleter<?> c;
5328	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5329	>	@SuppressWarnings("unchecked")
5330	>	ReduceValuesTask<K,V>
5331	>	t = (ReduceValuesTask<K,V>)c,
5332	>	s = t.rights;
5333	>	while (s != null) {
5334	>	V tr, sr;
5335	>	if ((sr = s.result) != null)
5336	>	t.result = (((tr = t.result) == null) ? sr :
5337	>	reducer.apply(tr, sr));
5338	>	s = t.rights = s.nextRight;
5339	>	}
5340	>	}
5341	>	}
5342	>	}
5343	>	}
5344	>
5345	>	@SuppressWarnings("serial")
5346	>	static final class ReduceEntriesTask<K,V>
5347	>	extends BulkTask<K,V,Map.Entry<K,V>> {
5348	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5349	>	Map.Entry<K,V> result;
5350	>	ReduceEntriesTask<K,V> rights, nextRight;
5351	>	ReduceEntriesTask
5352	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5353	>	ReduceEntriesTask<K,V> nextRight,
5354	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
5355	>	super(p, b, i, f, t); this.nextRight = nextRight;
5356	>	this.reducer = reducer;
5357	>	}
5358	>	public final Map.Entry<K,V> getRawResult() { return result; }
5359	>	public final void compute() {
5360	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
5361	>	if ((reducer = this.reducer) != null) {
5362	>	for (int i = baseIndex, f, h; batch > 0 &&
5363	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5364	>	addToPendingCount(1);
5365	>	(rights = new ReduceEntriesTask<K,V>
5366	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5367	>	rights, reducer)).fork();
5368	>	}
5369	>	Map.Entry<K,V> r = null;
5370	>	for (Node<K,V> p; (p = advance()) != null; )
5371	>	r = (r == null) ? p : reducer.apply(r, p);
5372	>	result = r;
5373	>	CountedCompleter<?> c;
5374	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5375	>	@SuppressWarnings("unchecked")
5376	>	ReduceEntriesTask<K,V>
5377	>	t = (ReduceEntriesTask<K,V>)c,
5378	>	s = t.rights;
5379	>	while (s != null) {
5380	>	Map.Entry<K,V> tr, sr;
5381	>	if ((sr = s.result) != null)
5382	>	t.result = (((tr = t.result) == null) ? sr :
5383	>	reducer.apply(tr, sr));
5384	>	s = t.rights = s.nextRight;
5385	>	}
5386	>	}
5387	>	}
5388	>	}
5389	>	}
5390	>
5391	>	@SuppressWarnings("serial")
5392	>	static final class MapReduceKeysTask<K,V,U>
5393	>	extends BulkTask<K,V,U> {
5394	>	final Function<? super K, ? extends U> transformer;
5395	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5396	>	U result;
5397	>	MapReduceKeysTask<K,V,U> rights, nextRight;
5398	>	MapReduceKeysTask
5399	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5400	>	MapReduceKeysTask<K,V,U> nextRight,
5401	>	Function<? super K, ? extends U> transformer,
5402	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5403	>	super(p, b, i, f, t); this.nextRight = nextRight;
5404	>	this.transformer = transformer;
5405	>	this.reducer = reducer;
5406	>	}
5407	>	public final U getRawResult() { return result; }
5408	>	public final void compute() {
5409	>	final Function<? super K, ? extends U> transformer;
5410	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5411	>	if ((transformer = this.transformer) != null &&
5412	>	(reducer = this.reducer) != null) {
5413	>	for (int i = baseIndex, f, h; batch > 0 &&
5414	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5415	>	addToPendingCount(1);
5416	>	(rights = new MapReduceKeysTask<K,V,U>
5417	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5418	>	rights, transformer, reducer)).fork();
5419	>	}
5420	>	U r = null;
5421	>	for (Node<K,V> p; (p = advance()) != null; ) {
5422	>	U u;
5423	>	if ((u = transformer.apply(p.key)) != null)
5424	>	r = (r == null) ? u : reducer.apply(r, u);
5425	>	}
5426	>	result = r;
5427	>	CountedCompleter<?> c;
5428	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5429	>	@SuppressWarnings("unchecked")
5430	>	MapReduceKeysTask<K,V,U>
5431	>	t = (MapReduceKeysTask<K,V,U>)c,
5432	>	s = t.rights;
5433	>	while (s != null) {
5434	>	U tr, sr;
5435	>	if ((sr = s.result) != null)
5436	>	t.result = (((tr = t.result) == null) ? sr :
5437	>	reducer.apply(tr, sr));
5438	>	s = t.rights = s.nextRight;
5439	>	}
5440	>	}
5441	>	}
5442	>	}
5443	>	}
5444	>
5445	>	@SuppressWarnings("serial")
5446	>	static final class MapReduceValuesTask<K,V,U>
5447	>	extends BulkTask<K,V,U> {
5448	>	final Function<? super V, ? extends U> transformer;
5449	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5450	>	U result;
5451	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5452	>	MapReduceValuesTask
5453	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5454	>	MapReduceValuesTask<K,V,U> nextRight,
5455	>	Function<? super V, ? extends U> transformer,
5456	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5457	>	super(p, b, i, f, t); this.nextRight = nextRight;
5458	>	this.transformer = transformer;
5459	>	this.reducer = reducer;
5460	>	}
5461	>	public final U getRawResult() { return result; }
5462	>	public final void compute() {
5463	>	final Function<? super V, ? extends U> transformer;
5464	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5465	>	if ((transformer = this.transformer) != null &&
5466	>	(reducer = this.reducer) != null) {
5467	>	for (int i = baseIndex, f, h; batch > 0 &&
5468	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5469	>	addToPendingCount(1);
5470	>	(rights = new MapReduceValuesTask<K,V,U>
5471	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5472	>	rights, transformer, reducer)).fork();
5473	>	}
5474	>	U r = null;
5475	>	for (Node<K,V> p; (p = advance()) != null; ) {
5476	>	U u;
5477	>	if ((u = transformer.apply(p.val)) != null)
5478	>	r = (r == null) ? u : reducer.apply(r, u);
5479	>	}
5480	>	result = r;
5481	>	CountedCompleter<?> c;
5482	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5483	>	@SuppressWarnings("unchecked")
5484	>	MapReduceValuesTask<K,V,U>
5485	>	t = (MapReduceValuesTask<K,V,U>)c,
5486	>	s = t.rights;
5487	>	while (s != null) {
5488	>	U tr, sr;
5489	>	if ((sr = s.result) != null)
5490	>	t.result = (((tr = t.result) == null) ? sr :
5491	>	reducer.apply(tr, sr));
5492	>	s = t.rights = s.nextRight;
5493	>	}
5494	>	}
5495	>	}
5496	>	}
5497	>	}
5498	>
5499	>	@SuppressWarnings("serial")
5500	>	static final class MapReduceEntriesTask<K,V,U>
5501	>	extends BulkTask<K,V,U> {
5502	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5503	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5504	>	U result;
5505	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5506	>	MapReduceEntriesTask
5507	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5508	>	MapReduceEntriesTask<K,V,U> nextRight,
5509	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5510	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5511	>	super(p, b, i, f, t); this.nextRight = nextRight;
5512	>	this.transformer = transformer;
5513	>	this.reducer = reducer;
5514	>	}
5515	>	public final U getRawResult() { return result; }
5516	>	public final void compute() {
5517	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5518	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5519	>	if ((transformer = this.transformer) != null &&
5520	>	(reducer = this.reducer) != null) {
5521	>	for (int i = baseIndex, f, h; batch > 0 &&
5522	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5523	>	addToPendingCount(1);
5524	>	(rights = new MapReduceEntriesTask<K,V,U>
5525	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5526	>	rights, transformer, reducer)).fork();
5527	>	}
5528	>	U r = null;
5529	>	for (Node<K,V> p; (p = advance()) != null; ) {
5530	>	U u;
5531	>	if ((u = transformer.apply(p)) != null)
5532	>	r = (r == null) ? u : reducer.apply(r, u);
5533	>	}
5534	>	result = r;
5535	>	CountedCompleter<?> c;
5536	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5537	>	@SuppressWarnings("unchecked")
5538	>	MapReduceEntriesTask<K,V,U>
5539	>	t = (MapReduceEntriesTask<K,V,U>)c,
5540	>	s = t.rights;
5541	>	while (s != null) {
5542	>	U tr, sr;
5543	>	if ((sr = s.result) != null)
5544	>	t.result = (((tr = t.result) == null) ? sr :
5545	>	reducer.apply(tr, sr));
5546	>	s = t.rights = s.nextRight;
5547	>	}
5548	>	}
5549	>	}
5550	>	}
5551	>	}
5552	>
5553	>	@SuppressWarnings("serial")
5554	>	static final class MapReduceMappingsTask<K,V,U>
5555	>	extends BulkTask<K,V,U> {
5556	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5557	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5558	>	U result;
5559	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5560	>	MapReduceMappingsTask
5561	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5562	>	MapReduceMappingsTask<K,V,U> nextRight,
5563	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5564	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5565	>	super(p, b, i, f, t); this.nextRight = nextRight;
5566	>	this.transformer = transformer;
5567	>	this.reducer = reducer;
5568	>	}
5569	>	public final U getRawResult() { return result; }
5570	>	public final void compute() {
5571	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5572	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5573	>	if ((transformer = this.transformer) != null &&
5574	>	(reducer = this.reducer) != null) {
5575	>	for (int i = baseIndex, f, h; batch > 0 &&
5576	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5577	>	addToPendingCount(1);
5578	>	(rights = new MapReduceMappingsTask<K,V,U>
5579	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5580	>	rights, transformer, reducer)).fork();
5581	>	}
5582	>	U r = null;
5583	>	for (Node<K,V> p; (p = advance()) != null; ) {
5584	>	U u;
5585	>	if ((u = transformer.apply(p.key, p.val)) != null)
5586	>	r = (r == null) ? u : reducer.apply(r, u);
5587	>	}
5588	>	result = r;
5589	>	CountedCompleter<?> c;
5590	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5591	>	@SuppressWarnings("unchecked")
5592	>	MapReduceMappingsTask<K,V,U>
5593	>	t = (MapReduceMappingsTask<K,V,U>)c,
5594	>	s = t.rights;
5595	>	while (s != null) {
5596	>	U tr, sr;
5597	>	if ((sr = s.result) != null)
5598	>	t.result = (((tr = t.result) == null) ? sr :
5599	>	reducer.apply(tr, sr));
5600	>	s = t.rights = s.nextRight;
5601	>	}
5602	>	}
5603	>	}
5604	>	}
5605	>	}
5606	>
5607	>	@SuppressWarnings("serial")
5608	>	static final class MapReduceKeysToDoubleTask<K,V>
5609	>	extends BulkTask<K,V,Double> {
5610	>	final ToDoubleFunction<? super K> transformer;
5611	>	final DoubleBinaryOperator reducer;
5612	>	final double basis;
5613	>	double result;
5614	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5615	>	MapReduceKeysToDoubleTask
5616	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5617	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5618	>	ToDoubleFunction<? super K> transformer,
5619	>	double basis,
5620	>	DoubleBinaryOperator reducer) {
5621	>	super(p, b, i, f, t); this.nextRight = nextRight;
5622	>	this.transformer = transformer;
5623	>	this.basis = basis; this.reducer = reducer;
5624	>	}
5625	>	public final Double getRawResult() { return result; }
5626	>	public final void compute() {
5627	>	final ToDoubleFunction<? super K> transformer;
5628	>	final DoubleBinaryOperator reducer;
5629	>	if ((transformer = this.transformer) != null &&
5630	>	(reducer = this.reducer) != null) {
5631	>	double r = this.basis;
5632	>	for (int i = baseIndex, f, h; batch > 0 &&
5633	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5634	>	addToPendingCount(1);
5635	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5636	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5637	>	rights, transformer, r, reducer)).fork();
5638	>	}
5639	>	for (Node<K,V> p; (p = advance()) != null; )
5640	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key));
5641	>	result = r;
5642	>	CountedCompleter<?> c;
5643	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5644	>	@SuppressWarnings("unchecked")
5645	>	MapReduceKeysToDoubleTask<K,V>
5646	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5647	>	s = t.rights;
5648	>	while (s != null) {
5649	>	t.result = reducer.applyAsDouble(t.result, s.result);
5650	>	s = t.rights = s.nextRight;
5651	>	}
5652	>	}
5653	>	}
5654	>	}
5655	>	}
5656	>
5657	>	@SuppressWarnings("serial")
5658	>	static final class MapReduceValuesToDoubleTask<K,V>
5659	>	extends BulkTask<K,V,Double> {
5660	>	final ToDoubleFunction<? super V> transformer;
5661	>	final DoubleBinaryOperator reducer;
5662	>	final double basis;
5663	>	double result;
5664	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5665	>	MapReduceValuesToDoubleTask
5666	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5667	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5668	>	ToDoubleFunction<? super V> transformer,
5669	>	double basis,
5670	>	DoubleBinaryOperator reducer) {
5671	>	super(p, b, i, f, t); this.nextRight = nextRight;
5672	>	this.transformer = transformer;
5673	>	this.basis = basis; this.reducer = reducer;
5674	>	}
5675	>	public final Double getRawResult() { return result; }
5676	>	public final void compute() {
5677	>	final ToDoubleFunction<? super V> transformer;
5678	>	final DoubleBinaryOperator reducer;
5679	>	if ((transformer = this.transformer) != null &&
5680	>	(reducer = this.reducer) != null) {
5681	>	double r = this.basis;
5682	>	for (int i = baseIndex, f, h; batch > 0 &&
5683	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5684	>	addToPendingCount(1);
5685	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5686	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5687	>	rights, transformer, r, reducer)).fork();
5688	>	}
5689	>	for (Node<K,V> p; (p = advance()) != null; )
5690	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5691	>	result = r;
5692	>	CountedCompleter<?> c;
5693	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5694	>	@SuppressWarnings("unchecked")
5695	>	MapReduceValuesToDoubleTask<K,V>
5696	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5697	>	s = t.rights;
5698	>	while (s != null) {
5699	>	t.result = reducer.applyAsDouble(t.result, s.result);
5700	>	s = t.rights = s.nextRight;
5701	>	}
5702	>	}
5703	>	}
5704	>	}
5705	>	}
5706	>
5707	>	@SuppressWarnings("serial")
5708	>	static final class MapReduceEntriesToDoubleTask<K,V>
5709	>	extends BulkTask<K,V,Double> {
5710	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5711	>	final DoubleBinaryOperator reducer;
5712	>	final double basis;
5713	>	double result;
5714	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5715	>	MapReduceEntriesToDoubleTask
5716	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5717	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5718	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5719	>	double basis,
5720	>	DoubleBinaryOperator reducer) {
5721	>	super(p, b, i, f, t); this.nextRight = nextRight;
5722	>	this.transformer = transformer;
5723	>	this.basis = basis; this.reducer = reducer;
5724	>	}
5725	>	public final Double getRawResult() { return result; }
5726	>	public final void compute() {
5727	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5728	>	final DoubleBinaryOperator reducer;
5729	>	if ((transformer = this.transformer) != null &&
5730	>	(reducer = this.reducer) != null) {
5731	>	double r = this.basis;
5732	>	for (int i = baseIndex, f, h; batch > 0 &&
5733	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5734	>	addToPendingCount(1);
5735	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5736	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5737	>	rights, transformer, r, reducer)).fork();
5738	>	}
5739	>	for (Node<K,V> p; (p = advance()) != null; )
5740	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5741	>	result = r;
5742	>	CountedCompleter<?> c;
5743	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5744	>	@SuppressWarnings("unchecked")
5745	>	MapReduceEntriesToDoubleTask<K,V>
5746	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5747	>	s = t.rights;
5748	>	while (s != null) {
5749	>	t.result = reducer.applyAsDouble(t.result, s.result);
5750	>	s = t.rights = s.nextRight;
5751	>	}
5752	>	}
5753	>	}
5754	>	}
5755	>	}
5756	>
5757	>	@SuppressWarnings("serial")
5758	>	static final class MapReduceMappingsToDoubleTask<K,V>
5759	>	extends BulkTask<K,V,Double> {
5760	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5761	>	final DoubleBinaryOperator reducer;
5762	>	final double basis;
5763	>	double result;
5764	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5765	>	MapReduceMappingsToDoubleTask
5766	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5767	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5768	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5769	>	double basis,
5770	>	DoubleBinaryOperator reducer) {
5771	>	super(p, b, i, f, t); this.nextRight = nextRight;
5772	>	this.transformer = transformer;
5773	>	this.basis = basis; this.reducer = reducer;
5774	>	}
5775	>	public final Double getRawResult() { return result; }
5776	>	public final void compute() {
5777	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5778	>	final DoubleBinaryOperator reducer;
5779	>	if ((transformer = this.transformer) != null &&
5780	>	(reducer = this.reducer) != null) {
5781	>	double r = this.basis;
5782	>	for (int i = baseIndex, f, h; batch > 0 &&
5783	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5784	>	addToPendingCount(1);
5785	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5786	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5787	>	rights, transformer, r, reducer)).fork();
5788	>	}
5789	>	for (Node<K,V> p; (p = advance()) != null; )
5790	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val));
5791	>	result = r;
5792	>	CountedCompleter<?> c;
5793	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5794	>	@SuppressWarnings("unchecked")
5795	>	MapReduceMappingsToDoubleTask<K,V>
5796	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5797	>	s = t.rights;
5798	>	while (s != null) {
5799	>	t.result = reducer.applyAsDouble(t.result, s.result);
5800	>	s = t.rights = s.nextRight;
5801	>	}
5802	>	}
5803	>	}
5804	>	}
5805	>	}
5806	>
5807	>	@SuppressWarnings("serial")
5808	>	static final class MapReduceKeysToLongTask<K,V>
5809	>	extends BulkTask<K,V,Long> {
5810	>	final ToLongFunction<? super K> transformer;
5811	>	final LongBinaryOperator reducer;
5812	>	final long basis;
5813	>	long result;
5814	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5815	>	MapReduceKeysToLongTask
5816	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5817	>	MapReduceKeysToLongTask<K,V> nextRight,
5818	>	ToLongFunction<? super K> transformer,
5819	>	long basis,
5820	>	LongBinaryOperator reducer) {
5821	>	super(p, b, i, f, t); this.nextRight = nextRight;
5822	>	this.transformer = transformer;
5823	>	this.basis = basis; this.reducer = reducer;
5824	>	}
5825	>	public final Long getRawResult() { return result; }
5826	>	public final void compute() {
5827	>	final ToLongFunction<? super K> transformer;
5828	>	final LongBinaryOperator reducer;
5829	>	if ((transformer = this.transformer) != null &&
5830	>	(reducer = this.reducer) != null) {
5831	>	long r = this.basis;
5832	>	for (int i = baseIndex, f, h; batch > 0 &&
5833	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5834	>	addToPendingCount(1);
5835	>	(rights = new MapReduceKeysToLongTask<K,V>
5836	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5837	>	rights, transformer, r, reducer)).fork();
5838	>	}
5839	>	for (Node<K,V> p; (p = advance()) != null; )
5840	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key));
5841	>	result = r;
5842	>	CountedCompleter<?> c;
5843	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5844	>	@SuppressWarnings("unchecked")
5845	>	MapReduceKeysToLongTask<K,V>
5846	>	t = (MapReduceKeysToLongTask<K,V>)c,
5847	>	s = t.rights;
5848	>	while (s != null) {
5849	>	t.result = reducer.applyAsLong(t.result, s.result);
5850	>	s = t.rights = s.nextRight;
5851	>	}
5852	>	}
5853	>	}
5854	>	}
5855	>	}
5856	>
5857	>	@SuppressWarnings("serial")
5858	>	static final class MapReduceValuesToLongTask<K,V>
5859	>	extends BulkTask<K,V,Long> {
5860	>	final ToLongFunction<? super V> transformer;
5861	>	final LongBinaryOperator reducer;
5862	>	final long basis;
5863	>	long result;
5864	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5865	>	MapReduceValuesToLongTask
5866	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5867	>	MapReduceValuesToLongTask<K,V> nextRight,
5868	>	ToLongFunction<? super V> transformer,
5869	>	long basis,
5870	>	LongBinaryOperator reducer) {
5871	>	super(p, b, i, f, t); this.nextRight = nextRight;
5872	>	this.transformer = transformer;
5873	>	this.basis = basis; this.reducer = reducer;
5874	>	}
5875	>	public final Long getRawResult() { return result; }
5876	>	public final void compute() {
5877	>	final ToLongFunction<? super V> transformer;
5878	>	final LongBinaryOperator reducer;
5879	>	if ((transformer = this.transformer) != null &&
5880	>	(reducer = this.reducer) != null) {
5881	>	long r = this.basis;
5882	>	for (int i = baseIndex, f, h; batch > 0 &&
5883	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5884	>	addToPendingCount(1);
5885	>	(rights = new MapReduceValuesToLongTask<K,V>
5886	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5887	>	rights, transformer, r, reducer)).fork();
5888	>	}
5889	>	for (Node<K,V> p; (p = advance()) != null; )
5890	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
5891	>	result = r;
5892	>	CountedCompleter<?> c;
5893	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5894	>	@SuppressWarnings("unchecked")
5895	>	MapReduceValuesToLongTask<K,V>
5896	>	t = (MapReduceValuesToLongTask<K,V>)c,
5897	>	s = t.rights;
5898	>	while (s != null) {
5899	>	t.result = reducer.applyAsLong(t.result, s.result);
5900	>	s = t.rights = s.nextRight;
5901	>	}
5902	>	}
5903	>	}
5904	>	}
5905	>	}
5906	>
5907	>	@SuppressWarnings("serial")
5908	>	static final class MapReduceEntriesToLongTask<K,V>
5909	>	extends BulkTask<K,V,Long> {
5910	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5911	>	final LongBinaryOperator reducer;
5912	>	final long basis;
5913	>	long result;
5914	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
5915	>	MapReduceEntriesToLongTask
5916	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5917	>	MapReduceEntriesToLongTask<K,V> nextRight,
5918	>	ToLongFunction<Map.Entry<K,V>> transformer,
5919	>	long basis,
5920	>	LongBinaryOperator reducer) {
5921	>	super(p, b, i, f, t); this.nextRight = nextRight;
5922	>	this.transformer = transformer;
5923	>	this.basis = basis; this.reducer = reducer;
5924	>	}
5925	>	public final Long getRawResult() { return result; }
5926	>	public final void compute() {
5927	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5928	>	final LongBinaryOperator reducer;
5929	>	if ((transformer = this.transformer) != null &&
5930	>	(reducer = this.reducer) != null) {
5931	>	long r = this.basis;
5932	>	for (int i = baseIndex, f, h; batch > 0 &&
5933	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5934	>	addToPendingCount(1);
5935	>	(rights = new MapReduceEntriesToLongTask<K,V>
5936	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5937	>	rights, transformer, r, reducer)).fork();
5938	>	}
5939	>	for (Node<K,V> p; (p = advance()) != null; )
5940	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
5941	>	result = r;
5942	>	CountedCompleter<?> c;
5943	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5944	>	@SuppressWarnings("unchecked")
5945	>	MapReduceEntriesToLongTask<K,V>
5946	>	t = (MapReduceEntriesToLongTask<K,V>)c,
5947	>	s = t.rights;
5948	>	while (s != null) {
5949	>	t.result = reducer.applyAsLong(t.result, s.result);
5950	>	s = t.rights = s.nextRight;
5951	>	}
5952	>	}
5953	>	}
5954	>	}
5955	>	}
5956	>
5957	>	@SuppressWarnings("serial")
5958	>	static final class MapReduceMappingsToLongTask<K,V>
5959	>	extends BulkTask<K,V,Long> {
5960	>	final ToLongBiFunction<? super K, ? super V> transformer;
5961	>	final LongBinaryOperator reducer;
5962	>	final long basis;
5963	>	long result;
5964	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
5965	>	MapReduceMappingsToLongTask
5966	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5967	>	MapReduceMappingsToLongTask<K,V> nextRight,
5968	>	ToLongBiFunction<? super K, ? super V> transformer,
5969	>	long basis,
5970	>	LongBinaryOperator reducer) {
5971	>	super(p, b, i, f, t); this.nextRight = nextRight;
5972	>	this.transformer = transformer;
5973	>	this.basis = basis; this.reducer = reducer;
5974	>	}
5975	>	public final Long getRawResult() { return result; }
5976	>	public final void compute() {
5977	>	final ToLongBiFunction<? super K, ? super V> transformer;
5978	>	final LongBinaryOperator reducer;
5979	>	if ((transformer = this.transformer) != null &&
5980	>	(reducer = this.reducer) != null) {
5981	>	long r = this.basis;
5982	>	for (int i = baseIndex, f, h; batch > 0 &&
5983	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5984	>	addToPendingCount(1);
5985	>	(rights = new MapReduceMappingsToLongTask<K,V>
5986	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5987	>	rights, transformer, r, reducer)).fork();
5988	>	}
5989	>	for (Node<K,V> p; (p = advance()) != null; )
5990	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val));
5991	>	result = r;
5992	>	CountedCompleter<?> c;
5993	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5994	>	@SuppressWarnings("unchecked")
5995	>	MapReduceMappingsToLongTask<K,V>
5996	>	t = (MapReduceMappingsToLongTask<K,V>)c,
5997	>	s = t.rights;
5998	>	while (s != null) {
5999	>	t.result = reducer.applyAsLong(t.result, s.result);
6000	>	s = t.rights = s.nextRight;
6001	>	}
6002	>	}
6003	>	}
6004	>	}
6005	>	}
6006	>
6007	>	@SuppressWarnings("serial")
6008	>	static final class MapReduceKeysToIntTask<K,V>
6009	>	extends BulkTask<K,V,Integer> {
6010	>	final ToIntFunction<? super K> transformer;
6011	>	final IntBinaryOperator reducer;
6012	>	final int basis;
6013	>	int result;
6014	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
6015	>	MapReduceKeysToIntTask
6016	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6017	>	MapReduceKeysToIntTask<K,V> nextRight,
6018	>	ToIntFunction<? super K> transformer,
6019	>	int basis,
6020	>	IntBinaryOperator reducer) {
6021	>	super(p, b, i, f, t); this.nextRight = nextRight;
6022	>	this.transformer = transformer;
6023	>	this.basis = basis; this.reducer = reducer;
6024	>	}
6025	>	public final Integer getRawResult() { return result; }
6026	>	public final void compute() {
6027	>	final ToIntFunction<? super K> transformer;
6028	>	final IntBinaryOperator reducer;
6029	>	if ((transformer = this.transformer) != null &&
6030	>	(reducer = this.reducer) != null) {
6031	>	int r = this.basis;
6032	>	for (int i = baseIndex, f, h; batch > 0 &&
6033	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6034	>	addToPendingCount(1);
6035	>	(rights = new MapReduceKeysToIntTask<K,V>
6036	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6037	>	rights, transformer, r, reducer)).fork();
6038	>	}
6039	>	for (Node<K,V> p; (p = advance()) != null; )
6040	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key));
6041	>	result = r;
6042	>	CountedCompleter<?> c;
6043	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6044	>	@SuppressWarnings("unchecked")
6045	>	MapReduceKeysToIntTask<K,V>
6046	>	t = (MapReduceKeysToIntTask<K,V>)c,
6047	>	s = t.rights;
6048	>	while (s != null) {
6049	>	t.result = reducer.applyAsInt(t.result, s.result);
6050	>	s = t.rights = s.nextRight;
6051	>	}
6052	>	}
6053	>	}
6054	>	}
6055	>	}
6056	>
6057	>	@SuppressWarnings("serial")
6058	>	static final class MapReduceValuesToIntTask<K,V>
6059	>	extends BulkTask<K,V,Integer> {
6060	>	final ToIntFunction<? super V> transformer;
6061	>	final IntBinaryOperator reducer;
6062	>	final int basis;
6063	>	int result;
6064	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
6065	>	MapReduceValuesToIntTask
6066	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6067	>	MapReduceValuesToIntTask<K,V> nextRight,
6068	>	ToIntFunction<? super V> transformer,
6069	>	int basis,
6070	>	IntBinaryOperator reducer) {
6071	>	super(p, b, i, f, t); this.nextRight = nextRight;
6072	>	this.transformer = transformer;
6073	>	this.basis = basis; this.reducer = reducer;
6074	>	}
6075	>	public final Integer getRawResult() { return result; }
6076	>	public final void compute() {
6077	>	final ToIntFunction<? super V> transformer;
6078	>	final IntBinaryOperator reducer;
6079	>	if ((transformer = this.transformer) != null &&
6080	>	(reducer = this.reducer) != null) {
6081	>	int r = this.basis;
6082	>	for (int i = baseIndex, f, h; batch > 0 &&
6083	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6084	>	addToPendingCount(1);
6085	>	(rights = new MapReduceValuesToIntTask<K,V>
6086	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6087	>	rights, transformer, r, reducer)).fork();
6088	>	}
6089	>	for (Node<K,V> p; (p = advance()) != null; )
6090	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
6091	>	result = r;
6092	>	CountedCompleter<?> c;
6093	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6094	>	@SuppressWarnings("unchecked")
6095	>	MapReduceValuesToIntTask<K,V>
6096	>	t = (MapReduceValuesToIntTask<K,V>)c,
6097	>	s = t.rights;
6098	>	while (s != null) {
6099	>	t.result = reducer.applyAsInt(t.result, s.result);
6100	>	s = t.rights = s.nextRight;
6101	>	}
6102	>	}
6103	>	}
6104	>	}
6105	>	}
6106	>
6107	>	@SuppressWarnings("serial")
6108	>	static final class MapReduceEntriesToIntTask<K,V>
6109	>	extends BulkTask<K,V,Integer> {
6110	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6111	>	final IntBinaryOperator reducer;
6112	>	final int basis;
6113	>	int result;
6114	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
6115	>	MapReduceEntriesToIntTask
6116	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6117	>	MapReduceEntriesToIntTask<K,V> nextRight,
6118	>	ToIntFunction<Map.Entry<K,V>> transformer,
6119	>	int basis,
6120	>	IntBinaryOperator reducer) {
6121	>	super(p, b, i, f, t); this.nextRight = nextRight;
6122	>	this.transformer = transformer;
6123	>	this.basis = basis; this.reducer = reducer;
6124	>	}
6125	>	public final Integer getRawResult() { return result; }
6126	>	public final void compute() {
6127	>	final ToIntFunction<Map.Entry<K,V>> transformer;
6128	>	final IntBinaryOperator reducer;
6129	>	if ((transformer = this.transformer) != null &&
6130	>	(reducer = this.reducer) != null) {
6131	>	int r = this.basis;
6132	>	for (int i = baseIndex, f, h; batch > 0 &&
6133	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6134	>	addToPendingCount(1);
6135	>	(rights = new MapReduceEntriesToIntTask<K,V>
6136	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6137	>	rights, transformer, r, reducer)).fork();
6138	>	}
6139	>	for (Node<K,V> p; (p = advance()) != null; )
6140	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
6141	>	result = r;
6142	>	CountedCompleter<?> c;
6143	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6144	>	@SuppressWarnings("unchecked")
6145	>	MapReduceEntriesToIntTask<K,V>
6146	>	t = (MapReduceEntriesToIntTask<K,V>)c,
6147	>	s = t.rights;
6148	>	while (s != null) {
6149	>	t.result = reducer.applyAsInt(t.result, s.result);
6150	>	s = t.rights = s.nextRight;
6151	>	}
6152	>	}
6153	>	}
6154	>	}
6155	>	}
6156	>
6157	>	@SuppressWarnings("serial")
6158	>	static final class MapReduceMappingsToIntTask<K,V>
6159	>	extends BulkTask<K,V,Integer> {
6160	>	final ToIntBiFunction<? super K, ? super V> transformer;
6161	>	final IntBinaryOperator reducer;
6162	>	final int basis;
6163	>	int result;
6164	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
6165	>	MapReduceMappingsToIntTask
6166	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
6167	>	MapReduceMappingsToIntTask<K,V> nextRight,
6168	>	ToIntBiFunction<? super K, ? super V> transformer,
6169	>	int basis,
6170	>	IntBinaryOperator reducer) {
6171	>	super(p, b, i, f, t); this.nextRight = nextRight;
6172	>	this.transformer = transformer;
6173	>	this.basis = basis; this.reducer = reducer;
6174	>	}
6175	>	public final Integer getRawResult() { return result; }
6176	>	public final void compute() {
6177	>	final ToIntBiFunction<? super K, ? super V> transformer;
6178	>	final IntBinaryOperator reducer;
6179	>	if ((transformer = this.transformer) != null &&
6180	>	(reducer = this.reducer) != null) {
6181	>	int r = this.basis;
6182	>	for (int i = baseIndex, f, h; batch > 0 &&
6183	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
6184	>	addToPendingCount(1);
6185	>	(rights = new MapReduceMappingsToIntTask<K,V>
6186	>	(this, batch >>>= 1, baseLimit = h, f, tab,
6187	>	rights, transformer, r, reducer)).fork();
6188	>	}
6189	>	for (Node<K,V> p; (p = advance()) != null; )
6190	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val));
6191	>	result = r;
6192	>	CountedCompleter<?> c;
6193	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
6194	>	@SuppressWarnings("unchecked")
6195	>	MapReduceMappingsToIntTask<K,V>
6196	>	t = (MapReduceMappingsToIntTask<K,V>)c,
6197	>	s = t.rights;
6198	>	while (s != null) {
6199	>	t.result = reducer.applyAsInt(t.result, s.result);
6200	>	s = t.rights = s.nextRight;
6201	>	}
6202	>	}
6203	>	}
6204		}
6205		}
6206
6207		// Unsafe mechanics
6208	<	private static final sun.misc.Unsafe UNSAFE;
6209	<	private static final long SBASE;
6210	<	private static final int SSHIFT;
6211	<	private static final long TBASE;
6212	<	private static final int TSHIFT;
6208	>	private static final sun.misc.Unsafe U;
6209	>	private static final long SIZECTL;
6210	>	private static final long TRANSFERINDEX;
6211	>	private static final long BASECOUNT;
6212	>	private static final long CELLSBUSY;
6213	>	private static final long CELLVALUE;
6214	>	private static final long ABASE;
6215	>	private static final int ASHIFT;
6216
6217		static {
1467	–	int ss, ts;
6218		try {
6219	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
6220	<	Class<?> tc = HashEntry[].class;
6221	<	Class<?> sc = Segment[].class;
6222	<	TBASE = UNSAFE.arrayBaseOffset(tc);
6223	<	SBASE = UNSAFE.arrayBaseOffset(sc);
6224	<	ts = UNSAFE.arrayIndexScale(tc);
6225	<	ss = UNSAFE.arrayIndexScale(sc);
6219	>	U = sun.misc.Unsafe.getUnsafe();
6220	>	Class<?> k = ConcurrentHashMap.class;
6221	>	SIZECTL = U.objectFieldOffset
6222	>	(k.getDeclaredField("sizeCtl"));
6223	>	TRANSFERINDEX = U.objectFieldOffset
6224	>	(k.getDeclaredField("transferIndex"));
6225	>	BASECOUNT = U.objectFieldOffset
6226	>	(k.getDeclaredField("baseCount"));
6227	>	CELLSBUSY = U.objectFieldOffset
6228	>	(k.getDeclaredField("cellsBusy"));
6229	>	Class<?> ck = CounterCell.class;
6230	>	CELLVALUE = U.objectFieldOffset
6231	>	(ck.getDeclaredField("value"));
6232	>	Class<?> ak = Node[].class;
6233	>	ABASE = U.arrayBaseOffset(ak);
6234	>	int scale = U.arrayIndexScale(ak);
6235	>	if ((scale & (scale - 1)) != 0)
6236	>	throw new Error("data type scale not a power of two");
6237	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
6238		} catch (Exception e) {
6239		throw new Error(e);
6240		}
1479	–	if ((ss & (ss-1)) != 0 || (ts & (ts-1)) != 0)
1480	–	throw new Error("data type scale not a power of two");
1481	–	SSHIFT = 31 - Integer.numberOfLeadingZeros(ss);
1482	–	TSHIFT = 31 - Integer.numberOfLeadingZeros(ts);
6241		}
1484	–
6242		}

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