ViewVC Help

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

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

Comparing jsr166/src/main/java/util/concurrent/ConcurrentHashMap.java (file contents):
Revision 1.110 by jsr166, Wed Apr 27 14:06:30 2011 UTC vs.
Revision 1.215 by dl, Wed May 22 20:42:30 2013 UTC

#	Line 5 | Line 5
5		*/
6
7		package java.util.concurrent;
8	–	import java.util.concurrent.locks.*;
9	–	import java.util.*;
8		import java.io.Serializable;
9	<	import java.io.IOException;
10	<	import java.io.ObjectInputStream;
11	<	import java.io.ObjectOutputStream;
9	>	import java.io.ObjectStreamField;
10	>	import java.lang.reflect.ParameterizedType;
11	>	import java.lang.reflect.Type;
12	>	import java.util.Arrays;
13	>	import java.util.Collection;
14	>	import java.util.Comparator;
15	>	import java.util.ConcurrentModificationException;
16	>	import java.util.Enumeration;
17	>	import java.util.HashMap;
18	>	import java.util.Hashtable;
19	>	import java.util.Iterator;
20	>	import java.util.Map;
21	>	import java.util.NoSuchElementException;
22	>	import java.util.Set;
23	>	import java.util.Spliterator;
24	>	import java.util.concurrent.ConcurrentMap;
25	>	import java.util.concurrent.ForkJoinPool;
26	>	import java.util.concurrent.atomic.AtomicReference;
27	>	import java.util.concurrent.locks.ReentrantLock;
28	>	import java.util.concurrent.locks.StampedLock;
29	>	import java.util.function.BiConsumer;
30	>	import java.util.function.BiFunction;
31	>	import java.util.function.BinaryOperator;
32	>	import java.util.function.Consumer;
33	>	import java.util.function.DoubleBinaryOperator;
34	>	import java.util.function.Function;
35	>	import java.util.function.IntBinaryOperator;
36	>	import java.util.function.LongBinaryOperator;
37	>	import java.util.function.ToDoubleBiFunction;
38	>	import java.util.function.ToDoubleFunction;
39	>	import java.util.function.ToIntBiFunction;
40	>	import java.util.function.ToIntFunction;
41	>	import java.util.function.ToLongBiFunction;
42	>	import java.util.function.ToLongFunction;
43	>	import java.util.stream.Stream;
44
45		/**
46		* A hash table supporting full concurrency of retrievals and
47	<	* adjustable expected concurrency for updates. This class obeys the
47	>	* high expected concurrency for updates. This class obeys the
48		* same functional specification as {@link java.util.Hashtable}, and
49		* includes versions of methods corresponding to each method of
50	<	* <tt>Hashtable</tt>. However, even though all operations are
50	>	* {@code Hashtable}. However, even though all operations are
51		* thread-safe, retrieval operations do <em>not</em> entail locking,
52		* and there is <em>not</em> any support for locking the entire table
53		* in a way that prevents all access.  This class is fully
54	<	* interoperable with <tt>Hashtable</tt> in programs that rely on its
54	>	* interoperable with {@code Hashtable} in programs that rely on its
55		* thread safety but not on its synchronization details.
56		*
57	<	* <p> Retrieval operations (including <tt>get</tt>) generally do not
58	<	* block, so may overlap with update operations (including
59	<	* <tt>put</tt> and <tt>remove</tt>). Retrievals reflect the results
60	<	* of the most recently <em>completed</em> update operations holding
61	<	* upon their onset.  For aggregate operations such as <tt>putAll</tt>
62	<	* and <tt>clear</tt>, concurrent retrievals may reflect insertion or
63	<	* removal of only some entries.  Similarly, Iterators and
64	<	* Enumerations return elements reflecting the state of the hash table
65	<	* at some point at or since the creation of the iterator/enumeration.
66	<	* They do <em>not</em> throw {@link ConcurrentModificationException}.
67	<	* However, iterators are designed to be used by only one thread at a time.
68	<	*
69	<	* <p> The allowed concurrency among update operations is guided by
70	<	* the optional <tt>concurrencyLevel</tt> constructor argument
71	<	* (default <tt>16</tt>), which is used as a hint for internal sizing.  The
72	<	* table is internally partitioned to try to permit the indicated
73	<	* number of concurrent updates without contention. Because placement
74	<	* in hash tables is essentially random, the actual concurrency will
75	<	* vary.  Ideally, you should choose a value to accommodate as many
76	<	* threads as will ever concurrently modify the table. Using a
77	<	* significantly higher value than you need can waste space and time,
78	<	* and a significantly lower value can lead to thread contention. But
79	<	* overestimates and underestimates within an order of magnitude do
80	<	* not usually have much noticeable impact. A value of one is
81	<	* appropriate when it is known that only one thread will modify and
82	<	* all others will only read. Also, resizing this or any other kind of
83	<	* hash table is a relatively slow operation, so, when possible, it is
84	<	* a good idea to provide estimates of expected table sizes in
85	<	* constructors.
57	>	* <p>Retrieval operations (including {@code get}) generally do not
58	>	* block, so may overlap with update operations (including {@code put}
59	>	* and {@code remove}). Retrievals reflect the results of the most
60	>	* recently <em>completed</em> update operations holding upon their
61	>	* onset. (More formally, an update operation for a given key bears a
62	>	* <em>happens-before</em> relation with any (non-null) retrieval for
63	>	* that key reporting the updated value.)  For aggregate operations
64	>	* such as {@code putAll} and {@code clear}, concurrent retrievals may
65	>	* reflect insertion or removal of only some entries.  Similarly,
66	>	* Iterators and Enumerations return elements reflecting the state of
67	>	* the hash table at some point at or since the creation of the
68	>	* iterator/enumeration.  They do <em>not</em> throw {@link
69	>	* ConcurrentModificationException}.  However, iterators are designed
70	>	* to be used by only one thread at a time.  Bear in mind that the
71	>	* results of aggregate status methods including {@code size}, {@code
72	>	* isEmpty}, and {@code containsValue} are typically useful only when
73	>	* a map is not undergoing concurrent updates in other threads.
74	>	* Otherwise the results of these methods reflect transient states
75	>	* that may be adequate for monitoring or estimation purposes, but not
76	>	* for program control.
77	>	*
78	>	* <p>The table is dynamically expanded when there are too many
79	>	* collisions (i.e., keys that have distinct hash codes but fall into
80	>	* the same slot modulo the table size), with the expected average
81	>	* effect of maintaining roughly two bins per mapping (corresponding
82	>	* to a 0.75 load factor threshold for resizing). There may be much
83	>	* variance around this average as mappings are added and removed, but
84	>	* overall, this maintains a commonly accepted time/space tradeoff for
85	>	* hash tables.  However, resizing this or any other kind of hash
86	>	* table may be a relatively slow operation. When possible, it is a
87	>	* good idea to provide a size estimate as an optional {@code
88	>	* initialCapacity} constructor argument. An additional optional
89	>	* {@code loadFactor} constructor argument provides a further means of
90	>	* customizing initial table capacity by specifying the table density
91	>	* to be used in calculating the amount of space to allocate for the
92	>	* given number of elements.  Also, for compatibility with previous
93	>	* versions of this class, constructors may optionally specify an
94	>	* expected {@code concurrencyLevel} as an additional hint for
95	>	* internal sizing.  Note that using many keys with exactly the same
96	>	* {@code hashCode()} is a sure way to slow down performance of any
97	>	* hash table. To ameliorate impact, when keys are {@link Comparable},
98	>	* this class may use comparison order among keys to help break ties.
99	>	*
100	>	* <p>A {@link Set} projection of a ConcurrentHashMap may be created
101	>	* (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed
102	>	* (using {@link #keySet(Object)} when only keys are of interest, and the
103	>	* mapped values are (perhaps transiently) not used or all take the
104	>	* same mapping value.
105	>	*
106	>	* <p>A ConcurrentHashMap can be used as scalable frequency map (a
107	>	* form of histogram or multiset) by using {@link
108	>	* java.util.concurrent.atomic.LongAdder} values and initializing via
109	>	* {@link #computeIfAbsent computeIfAbsent}. For example, to add a count
110	>	* to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use
111	>	* {@code freqs.computeIfAbsent(k -> new LongAdder()).increment();}
112		*
113		* <p>This class and its views and iterators implement all of the
114		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
115		* interfaces.
116		*
117	<	* <p> Like {@link Hashtable} but unlike {@link HashMap}, this class
118	<	* does <em>not</em> allow <tt>null</tt> to be used as a key or value.
117	>	* <p>Like {@link Hashtable} but unlike {@link HashMap}, this class
118	>	* does <em>not</em> allow {@code null} to be used as a key or value.
119	>	*
120	>	* <p>ConcurrentHashMaps support a set of sequential and parallel bulk
121	>	* operations that, unlike most {@link Stream} methods, are designed
122	>	* to be safely, and often sensibly, applied even with maps that are
123	>	* being concurrently updated by other threads; for example, when
124	>	* computing a snapshot summary of the values in a shared registry.
125	>	* There are three kinds of operation, each with four forms, accepting
126	>	* functions with Keys, Values, Entries, and (Key, Value) arguments
127	>	* and/or return values. Because the elements of a ConcurrentHashMap
128	>	* are not ordered in any particular way, and may be processed in
129	>	* different orders in different parallel executions, the correctness
130	>	* of supplied functions should not depend on any ordering, or on any
131	>	* other objects or values that may transiently change while
132	>	* computation is in progress; and except for forEach actions, should
133	>	* ideally be side-effect-free. Bulk operations on {@link Map.Entry}
134	>	* objects do not support method {@code setValue}.
135	>	*
136	>	* <ul>
137	>	* <li> forEach: Perform a given action on each element.
138	>	* A variant form applies a given transformation on each element
139	>	* before performing the action.</li>
140	>	*
141	>	* <li> search: Return the first available non-null result of
142	>	* applying a given function on each element; skipping further
143	>	* search when a result is found.</li>
144	>	*
145	>	* <li> reduce: Accumulate each element.  The supplied reduction
146	>	* function cannot rely on ordering (more formally, it should be
147	>	* both associative and commutative).  There are five variants:
148	>	*
149	>	* <ul>
150	>	*
151	>	* <li> Plain reductions. (There is not a form of this method for
152	>	* (key, value) function arguments since there is no corresponding
153	>	* return type.)</li>
154	>	*
155	>	* <li> Mapped reductions that accumulate the results of a given
156	>	* function applied to each element.</li>
157	>	*
158	>	* <li> Reductions to scalar doubles, longs, and ints, using a
159	>	* given basis value.</li>
160	>	*
161	>	* </ul>
162	>	* </li>
163	>	* </ul>
164	>	*
165	>	* <p>These bulk operations accept a {@code parallelismThreshold}
166	>	* argument. Methods proceed sequentially if the current map size is
167	>	* estimated to be less than the given threshold. Using a value of
168	>	* {@code Long.MAX_VALUE} suppresses all parallelism.  Using a value
169	>	* of {@code 1} results in maximal parallelism.  In-between values can
170	>	* be used to trade off overhead versus throughput. Parallel forms use
171	>	* the {@link ForkJoinPool#commonPool()}.
172	>	*
173	>	* <p>The concurrency properties of bulk operations follow
174	>	* from those of ConcurrentHashMap: Any non-null result returned
175	>	* from {@code get(key)} and related access methods bears a
176	>	* happens-before relation with the associated insertion or
177	>	* update.  The result of any bulk operation reflects the
178	>	* composition of these per-element relations (but is not
179	>	* necessarily atomic with respect to the map as a whole unless it
180	>	* is somehow known to be quiescent).  Conversely, because keys
181	>	* and values in the map are never null, null serves as a reliable
182	>	* atomic indicator of the current lack of any result.  To
183	>	* maintain this property, null serves as an implicit basis for
184	>	* all non-scalar reduction operations. For the double, long, and
185	>	* int versions, the basis should be one that, when combined with
186	>	* any other value, returns that other value (more formally, it
187	>	* should be the identity element for the reduction). Most common
188	>	* reductions have these properties; for example, computing a sum
189	>	* with basis 0 or a minimum with basis MAX_VALUE.
190	>	*
191	>	* <p>Search and transformation functions provided as arguments
192	>	* should similarly return null to indicate the lack of any result
193	>	* (in which case it is not used). In the case of mapped
194	>	* reductions, this also enables transformations to serve as
195	>	* filters, returning null (or, in the case of primitive
196	>	* specializations, the identity basis) if the element should not
197	>	* be combined. You can create compound transformations and
198	>	* filterings by composing them yourself under this "null means
199	>	* there is nothing there now" rule before using them in search or
200	>	* reduce operations.
201	>	*
202	>	* <p>Methods accepting and/or returning Entry arguments maintain
203	>	* key-value associations. They may be useful for example when
204	>	* finding the key for the greatest value. Note that "plain" Entry
205	>	* arguments can be supplied using {@code new
206	>	* AbstractMap.SimpleEntry(k,v)}.
207	>	*
208	>	* <p>Bulk operations may complete abruptly, throwing an
209	>	* exception encountered in the application of a supplied
210	>	* function. Bear in mind when handling such exceptions that other
211	>	* concurrently executing functions could also have thrown
212	>	* exceptions, or would have done so if the first exception had
213	>	* not occurred.
214	>	*
215	>	* <p>Speedups for parallel compared to sequential forms are common
216	>	* but not guaranteed.  Parallel operations involving brief functions
217	>	* on small maps may execute more slowly than sequential forms if the
218	>	* underlying work to parallelize the computation is more expensive
219	>	* than the computation itself.  Similarly, parallelization may not
220	>	* lead to much actual parallelism if all processors are busy
221	>	* performing unrelated tasks.
222	>	*
223	>	* <p>All arguments to all task methods must be non-null.
224		*
225		* <p>This class is a member of the
226		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
#	Line 70 | Line 231 | import java.io.ObjectOutputStream;
231		* @param <K> the type of keys maintained by this map
232		* @param <V> the type of mapped values
233		*/
234	<	public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
235	<	implements ConcurrentMap<K, V>, Serializable {
234	>	@SuppressWarnings({"unchecked", "rawtypes", "serial"})
235	>	public class ConcurrentHashMap<K,V> implements ConcurrentMap<K,V>, Serializable {
236		private static final long serialVersionUID = 7249069246763182397L;
237
238		/*
239	<	* The basic strategy is to subdivide the table among Segments,
240	<	* each of which itself is a concurrently readable hash table.  To
241	<	* reduce footprint, all but one segments are constructed only
242	<	* when first needed (see ensureSegment). To maintain visibility
243	<	* in the presence of lazy construction, accesses to segments as
244	<	* well as elements of segment's table must use volatile access,
245	<	* which is done via Unsafe within methods segmentAt etc
246	<	* below. These provide the functionality of AtomicReferenceArrays
247	<	* but reduce the levels of indirection. Additionally,
248	<	* volatile-writes of table elements and entry "next" fields
249	<	* within locked operations use the cheaper "lazySet" forms of
250	<	* writes (via putOrderedObject) because these writes are always
251	<	* followed by lock releases that maintain sequential consistency
252	<	* of table updates.
253	<	*
254	<	* Historical note: The previous version of this class relied
255	<	* heavily on "final" fields, which avoided some volatile reads at
256	<	* the expense of a large initial footprint.  Some remnants of
257	<	* that design (including forced construction of segment 0) exist
258	<	* to ensure serialization compatibility.
239	>	* Overview:
240	>	*
241	>	* The primary design goal of this hash table is to maintain
242	>	* concurrent readability (typically method get(), but also
243	>	* iterators and related methods) while minimizing update
244	>	* contention. Secondary goals are to keep space consumption about
245	>	* the same or better than java.util.HashMap, and to support high
246	>	* initial insertion rates on an empty table by many threads.
247	>	*
248	>	* Each key-value mapping is held in a Node.  Because Node key
249	>	* fields can contain special values, they are defined using plain
250	>	* Object types (not type "K"). This leads to a lot of explicit
251	>	* casting (and the use of class-wide warning suppressions).  It
252	>	* also allows some of the public methods to be factored into a
253	>	* smaller number of internal methods (although sadly not so for
254	>	* the five variants of put-related operations). The
255	>	* validation-based approach explained below leads to a lot of
256	>	* code sprawl because retry-control precludes factoring into
257	>	* smaller methods.
258	>	*
259	>	* The table is lazily initialized to a power-of-two size upon the
260	>	* first insertion.  Each bin in the table normally contains a
261	>	* list of Nodes (most often, the list has only zero or one Node).
262	>	* Table accesses require volatile/atomic reads, writes, and
263	>	* CASes.  Because there is no other way to arrange this without
264	>	* adding further indirections, we use intrinsics
265	>	* (sun.misc.Unsafe) operations.
266	>	*
267	>	* We use the top (sign) bit of Node hash fields for control
268	>	* purposes -- it is available anyway because of addressing
269	>	* constraints.  Nodes with negative hash fields are forwarding
270	>	* nodes to either TreeBins or resized tables.  The lower 31 bits
271	>	* of each normal Node's hash field contain a transformation of
272	>	* the key's hash code.
273	>	*
274	>	* Insertion (via put or its variants) of the first node in an
275	>	* empty bin is performed by just CASing it to the bin.  This is
276	>	* by far the most common case for put operations under most
277	>	* key/hash distributions.  Other update operations (insert,
278	>	* delete, and replace) require locks.  We do not want to waste
279	>	* the space required to associate a distinct lock object with
280	>	* each bin, so instead use the first node of a bin list itself as
281	>	* a lock. Locking support for these locks relies on builtin
282	>	* "synchronized" monitors.
283	>	*
284	>	* Using the first node of a list as a lock does not by itself
285	>	* suffice though: When a node is locked, any update must first
286	>	* validate that it is still the first node after locking it, and
287	>	* retry if not. Because new nodes are always appended to lists,
288	>	* once a node is first in a bin, it remains first until deleted
289	>	* or the bin becomes invalidated (upon resizing).
290	>	*
291	>	* The main disadvantage of per-bin locks is that other update
292	>	* operations on other nodes in a bin list protected by the same
293	>	* lock can stall, for example when user equals() or mapping
294	>	* functions take a long time.  However, statistically, under
295	>	* random hash codes, this is not a common problem.  Ideally, the
296	>	* frequency of nodes in bins follows a Poisson distribution
297	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
298	>	* parameter of about 0.5 on average, given the resizing threshold
299	>	* of 0.75, although with a large variance because of resizing
300	>	* granularity. Ignoring variance, the expected occurrences of
301	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
302	>	* first values are:
303	>	*
304	>	* 0:    0.60653066
305	>	* 1:    0.30326533
306	>	* 2:    0.07581633
307	>	* 3:    0.01263606
308	>	* 4:    0.00157952
309	>	* 5:    0.00015795
310	>	* 6:    0.00001316
311	>	* 7:    0.00000094
312	>	* 8:    0.00000006
313	>	* more: less than 1 in ten million
314	>	*
315	>	* Lock contention probability for two threads accessing distinct
316	>	* elements is roughly 1 / (8 * #elements) under random hashes.
317	>	*
318	>	* Actual hash code distributions encountered in practice
319	>	* sometimes deviate significantly from uniform randomness.  This
320	>	* includes the case when N > (1<<30), so some keys MUST collide.
321	>	* Similarly for dumb or hostile usages in which multiple keys are
322	>	* designed to have identical hash codes. Also, although we guard
323	>	* against the worst effects of this (see method spread), sets of
324	>	* hashes may differ only in bits that do not impact their bin
325	>	* index for a given power-of-two mask.  So we use a secondary
326	>	* strategy that applies when the number of nodes in a bin exceeds
327	>	* a threshold, and at least one of the keys implements
328	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
329	>	* (a specialized form of red-black trees), bounding search time
330	>	* to O(log N).  Each search step in a TreeBin is at least twice as
331	>	* slow as in a regular list, but given that N cannot exceed
332	>	* (1<<64) (before running out of addresses) this bounds search
333	>	* steps, lock hold times, etc, to reasonable constants (roughly
334	>	* 100 nodes inspected per operation worst case) so long as keys
335	>	* are Comparable (which is very common -- String, Long, etc).
336	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
337	>	* traversal pointers as regular nodes, so can be traversed in
338	>	* iterators in the same way.
339	>	*
340	>	* The table is resized when occupancy exceeds a percentage
341	>	* threshold (nominally, 0.75, but see below).  Any thread
342	>	* noticing an overfull bin may assist in resizing after the
343	>	* initiating thread allocates and sets up the replacement
344	>	* array. However, rather than stalling, these other threads may
345	>	* proceed with insertions etc.  The use of TreeBins shields us
346	>	* from the worst case effects of overfilling while resizes are in
347	>	* progress.  Resizing proceeds by transferring bins, one by one,
348	>	* from the table to the next table. To enable concurrency, the
349	>	* next table must be (incrementally) prefilled with place-holders
350	>	* serving as reverse forwarders to the old table.  Because we are
351	>	* using power-of-two expansion, the elements from each bin must
352	>	* either stay at same index, or move with a power of two
353	>	* offset. We eliminate unnecessary node creation by catching
354	>	* cases where old nodes can be reused because their next fields
355	>	* won't change.  On average, only about one-sixth of them need
356	>	* cloning when a table doubles. The nodes they replace will be
357	>	* garbage collectable as soon as they are no longer referenced by
358	>	* any reader thread that may be in the midst of concurrently
359	>	* traversing table.  Upon transfer, the old table bin contains
360	>	* only a special forwarding node (with hash field "MOVED") that
361	>	* contains the next table as its key. On encountering a
362	>	* forwarding node, access and update operations restart, using
363	>	* the new table.
364	>	*
365	>	* Each bin transfer requires its bin lock, which can stall
366	>	* waiting for locks while resizing. However, because other
367	>	* threads can join in and help resize rather than contend for
368	>	* locks, average aggregate waits become shorter as resizing
369	>	* progresses.  The transfer operation must also ensure that all
370	>	* accessible bins in both the old and new table are usable by any
371	>	* traversal.  This is arranged by proceeding from the last bin
372	>	* (table.length - 1) up towards the first.  Upon seeing a
373	>	* forwarding node, traversals (see class Traverser) arrange to
374	>	* move to the new table without revisiting nodes.  However, to
375	>	* ensure that no intervening nodes are skipped, bin splitting can
376	>	* only begin after the associated reverse-forwarders are in
377	>	* place.
378	>	*
379	>	* The traversal scheme also applies to partial traversals of
380	>	* ranges of bins (via an alternate Traverser constructor)
381	>	* to support partitioned aggregate operations.  Also, read-only
382	>	* operations give up if ever forwarded to a null table, which
383	>	* provides support for shutdown-style clearing, which is also not
384	>	* currently implemented.
385	>	*
386	>	* Lazy table initialization minimizes footprint until first use,
387	>	* and also avoids resizings when the first operation is from a
388	>	* putAll, constructor with map argument, or deserialization.
389	>	* These cases attempt to override the initial capacity settings,
390	>	* but harmlessly fail to take effect in cases of races.
391	>	*
392	>	* The element count is maintained using a specialization of
393	>	* LongAdder. We need to incorporate a specialization rather than
394	>	* just use a LongAdder in order to access implicit
395	>	* contention-sensing that leads to creation of multiple
396	>	* Cells.  The counter mechanics avoid contention on
397	>	* updates but can encounter cache thrashing if read too
398	>	* frequently during concurrent access. To avoid reading so often,
399	>	* resizing under contention is attempted only upon adding to a
400	>	* bin already holding two or more nodes. Under uniform hash
401	>	* distributions, the probability of this occurring at threshold
402	>	* is around 13%, meaning that only about 1 in 8 puts check
403	>	* threshold (and after resizing, many fewer do so). The bulk
404	>	* putAll operation further reduces contention by only committing
405	>	* count updates upon these size checks.
406	>	*
407	>	* Maintaining API and serialization compatibility with previous
408	>	* versions of this class introduces several oddities. Mainly: We
409	>	* leave untouched but unused constructor arguments refering to
410	>	* concurrencyLevel. We accept a loadFactor constructor argument,
411	>	* but apply it only to initial table capacity (which is the only
412	>	* time that we can guarantee to honor it.) We also declare an
413	>	* unused "Segment" class that is instantiated in minimal form
414	>	* only when serializing.
415		*/
416
417		/* ---------------- Constants -------------- */
418
419		/**
420	<	* The default initial capacity for this table,
421	<	* used when not otherwise specified in a constructor.
420	>	* The largest possible table capacity.  This value must be
421	>	* exactly 1<<30 to stay within Java array allocation and indexing
422	>	* bounds for power of two table sizes, and is further required
423	>	* because the top two bits of 32bit hash fields are used for
424	>	* control purposes.
425		*/
426	<	static final int DEFAULT_INITIAL_CAPACITY = 16;
426	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
427
428		/**
429	<	* The default load factor for this table, used when not
430	<	* otherwise specified in a constructor.
429	>	* The default initial table capacity.  Must be a power of 2
430	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
431		*/
432	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
432	>	private static final int DEFAULT_CAPACITY = 16;
433
434		/**
435	<	* The default concurrency level for this table, used when not
436	<	* otherwise specified in a constructor.
435	>	* The largest possible (non-power of two) array size.
436	>	* Needed by toArray and related methods.
437		*/
438	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
438	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
439
440		/**
441	<	* The maximum capacity, used if a higher value is implicitly
442	<	* specified by either of the constructors with arguments.  MUST
123	<	* be a power of two <= 1<<30 to ensure that entries are indexable
124	<	* using ints.
441	>	* The default concurrency level for this table. Unused but
442	>	* defined for compatibility with previous versions of this class.
443		*/
444	<	static final int MAXIMUM_CAPACITY = 1 << 30;
444	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
445
446		/**
447	<	* The minimum capacity for per-segment tables.  Must be a power
448	<	* of two, at least two to avoid immediate resizing on next use
449	<	* after lazy construction.
447	>	* The load factor for this table. Overrides of this value in
448	>	* constructors affect only the initial table capacity.  The
449	>	* actual floating point value isn't normally used -- it is
450	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
451	>	* the associated resizing threshold.
452		*/
453	<	static final int MIN_SEGMENT_TABLE_CAPACITY = 2;
453	>	private static final float LOAD_FACTOR = 0.75f;
454
455		/**
456	<	* The maximum number of segments to allow; used to bound
457	<	* constructor arguments. Must be power of two less than 1 << 24.
456	>	* The bin count threshold for using a tree rather than list for a
457	>	* bin.  The value reflects the approximate break-even point for
458	>	* using tree-based operations.
459		*/
460	<	static final int MAX_SEGMENTS = 1 << 16; // slightly conservative
460	>	private static final int TREE_THRESHOLD = 8;
461
462		/**
463	<	* Number of unsynchronized retries in size and containsValue
464	<	* methods before resorting to locking. This is used to avoid
465	<	* unbounded retries if tables undergo continuous modification
466	<	* which would make it impossible to obtain an accurate result.
463	>	* Minimum number of rebinnings per transfer step. Ranges are
464	>	* subdivided to allow multiple resizer threads.  This value
465	>	* serves as a lower bound to avoid resizers encountering
466	>	* excessive memory contention.  The value should be at least
467	>	* DEFAULT_CAPACITY.
468		*/
469	<	static final int RETRIES_BEFORE_LOCK = 2;
469	>	private static final int MIN_TRANSFER_STRIDE = 16;
470	>
471	>	/*
472	>	* Encodings for Node hash fields. See above for explanation.
473	>	*/
474	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
475	>	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
476	>
477	>	/** Number of CPUS, to place bounds on some sizings */
478	>	static final int NCPU = Runtime.getRuntime().availableProcessors();
479	>
480	>	/** For serialization compatibility. */
481	>	private static final ObjectStreamField[] serialPersistentFields = {
482	>	new ObjectStreamField("segments", Segment[].class),
483	>	new ObjectStreamField("segmentMask", Integer.TYPE),
484	>	new ObjectStreamField("segmentShift", Integer.TYPE)
485	>	};
486	>
487	>	/**
488	>	* A padded cell for distributing counts.  Adapted from LongAdder
489	>	* and Striped64.  See their internal docs for explanation.
490	>	*/
491	>	@sun.misc.Contended static final class Cell {
492	>	volatile long value;
493	>	Cell(long x) { value = x; }
494	>	}
495
496		/* ---------------- Fields -------------- */
497
498		/**
499	<	* Mask value for indexing into segments. The upper bits of a
500	<	* key's hash code are used to choose the segment.
499	>	* The array of bins. Lazily initialized upon first insertion.
500	>	* Size is always a power of two. Accessed directly by iterators.
501	>	*/
502	>	transient volatile Node<K,V>[] table;
503	>
504	>	/**
505	>	* The next table to use; non-null only while resizing.
506	>	*/
507	>	private transient volatile Node<K,V>[] nextTable;
508	>
509	>	/**
510	>	* Base counter value, used mainly when there is no contention,
511	>	* but also as a fallback during table initialization
512	>	* races. Updated via CAS.
513	>	*/
514	>	private transient volatile long baseCount;
515	>
516	>	/**
517	>	* Table initialization and resizing control.  When negative, the
518	>	* table is being initialized or resized: -1 for initialization,
519	>	* else -(1 + the number of active resizing threads).  Otherwise,
520	>	* when table is null, holds the initial table size to use upon
521	>	* creation, or 0 for default. After initialization, holds the
522	>	* next element count value upon which to resize the table.
523	>	*/
524	>	private transient volatile int sizeCtl;
525	>
526	>	/**
527	>	* The next table index (plus one) to split while resizing.
528	>	*/
529	>	private transient volatile int transferIndex;
530	>
531	>	/**
532	>	* The least available table index to split while resizing.
533		*/
534	<	final int segmentMask;
534	>	private transient volatile int transferOrigin;
535
536		/**
537	<	* Shift value for indexing within segments.
537	>	* Spinlock (locked via CAS) used when resizing and/or creating Cells.
538		*/
539	<	final int segmentShift;
539	>	private transient volatile int cellsBusy;
540
541		/**
542	<	* The segments, each of which is a specialized hash table.
542	>	* Table of counter cells. When non-null, size is a power of 2.
543	>	*/
544	>	private transient volatile Cell[] counterCells;
545	>
546	>	// views
547	>	private transient KeySetView<K,V> keySet;
548	>	private transient ValuesView<K,V> values;
549	>	private transient EntrySetView<K,V> entrySet;
550	>
551	>	/* ---------------- Table element access -------------- */
552	>
553	>	/*
554	>	* Volatile access methods are used for table elements as well as
555	>	* elements of in-progress next table while resizing.  Uses are
556	>	* null checked by callers, and implicitly bounds-checked, relying
557	>	* on the invariants that tab arrays have non-zero size, and all
558	>	* indices are masked with (tab.length - 1) which is never
559	>	* negative and always less than length. Note that, to be correct
560	>	* wrt arbitrary concurrency errors by users, bounds checks must
561	>	* operate on local variables, which accounts for some odd-looking
562	>	* inline assignments below.
563		*/
165	–	final Segment<K,V>[] segments;
564
565	<	transient Set<K> keySet;
566	<	transient Set<Map.Entry<K,V>> entrySet;
567	<	transient Collection<V> values;
565	>	static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) {
566	>	return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE);
567	>	}
568	>
569	>	static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i,
570	>	Node<K,V> c, Node<K,V> v) {
571	>	return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v);
572	>	}
573	>
574	>	static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) {
575	>	U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v);
576	>	}
577	>
578	>	/* ---------------- Nodes -------------- */
579
580		/**
581	<	* ConcurrentHashMap list entry. Note that this is never exported
582	<	* out as a user-visible Map.Entry.
581	>	* Key-value entry.  This class is never exported out as a
582	>	* user-mutable Map.Entry (i.e., one supporting setValue; see
583	>	* MapEntry below), but can be used for read-only traversals used
584	>	* in bulk tasks.  Nodes with a hash field of MOVED are special,
585	>	* and do not contain user keys or values (and are never
586	>	* exported).  Otherwise, keys and vals are never null.
587		*/
588	<	static final class HashEntry<K,V> {
588	>	static class Node<K,V> implements Map.Entry<K,V> {
589		final int hash;
590	<	final K key;
591	<	volatile V value;
592	<	volatile HashEntry<K,V> next;
590	>	final Object key;
591	>	volatile V val;
592	>	Node<K,V> next;
593
594	<	HashEntry(int hash, K key, V value, HashEntry<K,V> next) {
594	>	Node(int hash, Object key, V val, Node<K,V> next) {
595		this.hash = hash;
596		this.key = key;
597	<	this.value = value;
597	>	this.val = val;
598		this.next = next;
599		}
600
601	<	/**
602	<	* Sets next field with volatile write semantics.  (See above
603	<	* about use of putOrderedObject.)
604	<	*/
605	<	final void setNext(HashEntry<K,V> n) {
606	<	UNSAFE.putOrderedObject(this, nextOffset, n);
601	>	public final K getKey()       { return (K)key; }
602	>	public final V getValue()     { return val; }
603	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
604	>	public final String toString(){ return key + "=" + val; }
605	>	public final V setValue(V value) {
606	>	throw new UnsupportedOperationException();
607		}
608
609	<	// Unsafe mechanics
610	<	static final sun.misc.Unsafe UNSAFE;
611	<	static final long nextOffset;
612	<	static {
613	<	try {
614	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
615	<	Class k = HashEntry.class;
203	<	nextOffset = UNSAFE.objectFieldOffset
204	<	(k.getDeclaredField("next"));
205	<	} catch (Exception e) {
206	<	throw new Error(e);
207	<	}
609	>	public final boolean equals(Object o) {
610	>	Object k, v, u; Map.Entry<?,?> e;
611	>	return ((o instanceof Map.Entry) &&
612	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
613	>	(v = e.getValue()) != null &&
614	>	(k == key || k.equals(key)) &&
615	>	(v == (u = val) || v.equals(u)));
616		}
617		}
618
619		/**
620	<	* Gets the ith element of given table (if nonnull) with volatile
213	<	* read semantics. Note: This is manually integrated into a few
214	<	* performance-sensitive methods to reduce call overhead.
620	>	* Exported Entry for EntryIterator
621		*/
622	<	@SuppressWarnings("unchecked")
623	<	static final <K,V> HashEntry<K,V> entryAt(HashEntry<K,V>[] tab, int i) {
624	<	return (tab == null) ? null :
625	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
626	<	(tab, ((long)i << TSHIFT) + TBASE);
622	>	static final class MapEntry<K,V> implements Map.Entry<K,V> {
623	>	final K key; // non-null
624	>	V val;       // non-null
625	>	final ConcurrentHashMap<K,V> map;
626	>	MapEntry(K key, V val, ConcurrentHashMap<K,V> map) {
627	>	this.key = key;
628	>	this.val = val;
629	>	this.map = map;
630	>	}
631	>	public K getKey()        { return key; }
632	>	public V getValue()      { return val; }
633	>	public int hashCode()    { return key.hashCode() ^ val.hashCode(); }
634	>	public String toString() { return key + "=" + val; }
635	>
636	>	public boolean equals(Object o) {
637	>	Object k, v; Map.Entry<?,?> e;
638	>	return ((o instanceof Map.Entry) &&
639	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
640	>	(v = e.getValue()) != null &&
641	>	(k == key || k.equals(key)) &&
642	>	(v == val || v.equals(val)));
643	>	}
644	>
645	>	/**
646	>	* Sets our entry's value and writes through to the map. The
647	>	* value to return is somewhat arbitrary here. Since we do not
648	>	* necessarily track asynchronous changes, the most recent
649	>	* "previous" value could be different from what we return (or
650	>	* could even have been removed, in which case the put will
651	>	* re-establish). We do not and cannot guarantee more.
652	>	*/
653	>	public V setValue(V value) {
654	>	if (value == null) throw new NullPointerException();
655	>	V v = val;
656	>	val = value;
657	>	map.put(key, value);
658	>	return v;
659	>	}
660		}
661
662	+
663	+	/* ---------------- TreeBins -------------- */
664	+
665		/**
666	<	* Sets the ith element of given table, with volatile write
225	<	* semantics. (See above about use of putOrderedObject.)
666	>	* Nodes for use in TreeBins
667		*/
668	<	static final <K,V> void setEntryAt(HashEntry<K,V>[] tab, int i,
669	<	HashEntry<K,V> e) {
670	<	UNSAFE.putOrderedObject(tab, ((long)i << TSHIFT) + TBASE, e);
668	>	static final class TreeNode<K,V> extends Node<K,V> {
669	>	TreeNode<K,V> parent;  // red-black tree links
670	>	TreeNode<K,V> left;
671	>	TreeNode<K,V> right;
672	>	TreeNode<K,V> prev;    // needed to unlink next upon deletion
673	>	boolean red;
674	>
675	>	TreeNode(int hash, Object key, V val, Node<K,V> next,
676	>	TreeNode<K,V> parent) {
677	>	super(hash, key, val, next);
678	>	this.parent = parent;
679	>	}
680		}
681
682		/**
683	<	* Applies a supplemental hash function to a given hashCode, which
684	<	* defends against poor quality hash functions.  This is critical
685	<	* because ConcurrentHashMap uses power-of-two length hash tables,
686	<	* that otherwise encounter collisions for hashCodes that do not
687	<	* differ in lower or upper bits.
688	<	*/
689	<	private static int hash(int h) {
690	<	// Spread bits to regularize both segment and index locations,
691	<	// using variant of single-word Wang/Jenkins hash.
692	<	h += (h <<  15) ^ 0xffffcd7d;
693	<	h ^= (h >>> 10);
694	<	h += (h <<   3);
695	<	h ^= (h >>>  6);
696	<	h += (h <<   2) + (h << 14);
697	<	return h ^ (h >>> 16);
683	>	* Returns a Class for the given object of the form "class C
684	>	* implements Comparable<C>", if one exists, else null.  See below
685	>	* for explanation.
686	>	*/
687	>	static Class<?> comparableClassFor(Object x) {
688	>	Class<?> c, s, cmpc; Type[] ts, as; Type t; ParameterizedType p;
689	>	if ((c = x.getClass()) == String.class) // bypass checks
690	>	return c;
691	>	if ((cmpc = Comparable.class).isAssignableFrom(c)) {
692	>	while (cmpc.isAssignableFrom(s = c.getSuperclass()))
693	>	c = s; // find topmost comparable class
694	>	if ((ts = c.getGenericInterfaces()) != null) {
695	>	for (int i = 0; i < ts.length; ++i) {
696	>	if (((t = ts[i]) instanceof ParameterizedType) &&
697	>	((p = (ParameterizedType)t).getRawType() == cmpc) &&
698	>	(as = p.getActualTypeArguments()) != null &&
699	>	as.length == 1 && as[0] == c) // type arg is c
700	>	return c;
701	>	}
702	>	}
703	>	}
704	>	return null;
705		}
706
707		/**
708	<	* Segments are specialized versions of hash tables.  This
709	<	* subclasses from ReentrantLock opportunistically, just to
710	<	* simplify some locking and avoid separate construction.
708	>	* A specialized form of red-black tree for use in bins
709	>	* whose size exceeds a threshold.
710	>	*
711	>	* TreeBins use a special form of comparison for search and
712	>	* related operations (which is the main reason we cannot use
713	>	* existing collections such as TreeMaps). TreeBins contain
714	>	* Comparable elements, but may contain others, as well as
715	>	* elements that are Comparable but not necessarily Comparable
716	>	* for the same T, so we cannot invoke compareTo among them. To
717	>	* handle this, the tree is ordered primarily by hash value, then
718	>	* by Comparable.compareTo order if applicable.  On lookup at a
719	>	* node, if elements are not comparable or compare as 0 then both
720	>	* left and right children may need to be searched in the case of
721	>	* tied hash values. (This corresponds to the full list search
722	>	* that would be necessary if all elements were non-Comparable and
723	>	* had tied hashes.)  The red-black balancing code is updated from
724	>	* pre-jdk-collections
725	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
726	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
727	>	* Algorithms" (CLR).
728	>	*
729	>	* TreeBins also maintain a separate locking discipline than
730	>	* regular bins. Because they are forwarded via special MOVED
731	>	* nodes at bin heads (which can never change once established),
732	>	* we cannot use those nodes as locks. Instead, TreeBin extends
733	>	* StampedLock to support a form of read-write lock. For update
734	>	* operations and table validation, the exclusive form of lock
735	>	* behaves in the same way as bin-head locks. However, lookups use
736	>	* shared read-lock mechanics to allow multiple readers in the
737	>	* absence of writers.  Additionally, these lookups do not ever
738	>	* block: While the lock is not available, they proceed along the
739	>	* slow traversal path (via next-pointers) until the lock becomes
740	>	* available or the list is exhausted, whichever comes
741	>	* first. These cases are not fast, but maximize aggregate
742	>	* expected throughput.
743		*/
744	<	static final class Segment<K,V> extends ReentrantLock implements Serializable {
256	<	/*
257	<	* Segments maintain a table of entry lists that are always
258	<	* kept in a consistent state, so can be read (via volatile
259	<	* reads of segments and tables) without locking.  This
260	<	* requires replicating nodes when necessary during table
261	<	* resizing, so the old lists can be traversed by readers
262	<	* still using old version of table.
263	<	*
264	<	* This class defines only mutative methods requiring locking.
265	<	* Except as noted, the methods of this class perform the
266	<	* per-segment versions of ConcurrentHashMap methods.  (Other
267	<	* methods are integrated directly into ConcurrentHashMap
268	<	* methods.) These mutative methods use a form of controlled
269	<	* spinning on contention via methods scanAndLock and
270	<	* scanAndLockForPut. These intersperse tryLocks with
271	<	* traversals to locate nodes.  The main benefit is to absorb
272	<	* cache misses (which are very common for hash tables) while
273	<	* obtaining locks so that traversal is faster once
274	<	* acquired. We do not actually use the found nodes since they
275	<	* must be re-acquired under lock anyway to ensure sequential
276	<	* consistency of updates (and in any case may be undetectably
277	<	* stale), but they will normally be much faster to re-locate.
278	<	* Also, scanAndLockForPut speculatively creates a fresh node
279	<	* to use in put if no node is found.
280	<	*/
281	<
744	>	static final class TreeBin<K,V> extends StampedLock {
745		private static final long serialVersionUID = 2249069246763182397L;
746	+	transient TreeNode<K,V> root;  // root of tree
747	+	transient TreeNode<K,V> first; // head of next-pointer list
748
749	<	/**
750	<	* The maximum number of times to tryLock in a prescan before
751	<	* possibly blocking on acquire in preparation for a locked
752	<	* segment operation. On multiprocessors, using a bounded
753	<	* number of retries maintains cache acquired while locating
754	<	* nodes.
755	<	*/
756	<	static final int MAX_SCAN_RETRIES =
757	<	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
749	>	/** From CLR */
750	>	private void rotateLeft(TreeNode<K,V> p) {
751	>	if (p != null) {
752	>	TreeNode<K,V> r = p.right, pp, rl;
753	>	if ((rl = p.right = r.left) != null)
754	>	rl.parent = p;
755	>	if ((pp = r.parent = p.parent) == null)
756	>	root = r;
757	>	else if (pp.left == p)
758	>	pp.left = r;
759	>	else
760	>	pp.right = r;
761	>	r.left = p;
762	>	p.parent = r;
763	>	}
764	>	}
765
766	<	/**
767	<	* The per-segment table. Elements are accessed via
768	<	* entryAt/setEntryAt providing volatile semantics.
769	<	*/
770	<	transient volatile HashEntry<K,V>[] table;
766	>	/** From CLR */
767	>	private void rotateRight(TreeNode<K,V> p) {
768	>	if (p != null) {
769	>	TreeNode<K,V> l = p.left, pp, lr;
770	>	if ((lr = p.left = l.right) != null)
771	>	lr.parent = p;
772	>	if ((pp = l.parent = p.parent) == null)
773	>	root = l;
774	>	else if (pp.right == p)
775	>	pp.right = l;
776	>	else
777	>	pp.left = l;
778	>	l.right = p;
779	>	p.parent = l;
780	>	}
781	>	}
782
783		/**
784	<	* The number of elements. Accessed only either within locks
785	<	* or among other volatile reads that maintain visibility.
784	>	* Returns the TreeNode (or null if not found) for the given key
785	>	* starting at given root.
786		*/
787	<	transient int count;
787	>	final TreeNode<K,V> getTreeNode(int h, Object k, TreeNode<K,V> p,
788	>	Class<?> cc) {
789	>	while (p != null) {
790	>	int dir, ph; Object pk;
791	>	if ((ph = p.hash) != h)
792	>	dir = (h < ph) ? -1 : 1;
793	>	else if ((pk = p.key) == k || k.equals(pk))
794	>	return p;
795	>	else if (cc == null || comparableClassFor(pk) != cc ||
796	>	(dir = ((Comparable<Object>)k).compareTo(pk)) == 0) {
797	>	TreeNode<K,V> r, pr; // check both sides
798	>	if ((pr = p.right) != null && h >= pr.hash &&
799	>	(r = getTreeNode(h, k, pr, cc)) != null)
800	>	return r;
801	>	else // continue left
802	>	dir = -1;
803	>	}
804	>	p = (dir > 0) ? p.right : p.left;
805	>	}
806	>	return null;
807	>	}
808
809		/**
810	<	* The total number of mutative operations in this segment.
811	<	* Even though this may overflows 32 bits, it provides
812	<	* sufficient accuracy for stability checks in CHM isEmpty()
310	<	* and size() methods.  Accessed only either within locks or
311	<	* among other volatile reads that maintain visibility.
810	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
811	>	* read-lock to call getTreeNode, but during failure to get
812	>	* lock, searches along next links.
813		*/
814	<	transient int modCount;
814	>	final V getValue(int h, Object k) {
815	>	Class<?> cc = comparableClassFor(k);
816	>	Node<K,V> r = null;
817	>	for (Node<K,V> e = first; e != null; e = e.next) {
818	>	long s;
819	>	if ((s = tryReadLock()) != 0L) {
820	>	try {
821	>	r = getTreeNode(h, k, root, cc);
822	>	} finally {
823	>	unlockRead(s);
824	>	}
825	>	break;
826	>	}
827	>	else if (e.hash == h && k.equals(e.key)) {
828	>	r = e;
829	>	break;
830	>	}
831	>	}
832	>	return r == null ? null : r.val;
833	>	}
834
835		/**
836	<	* The table is rehashed when its size exceeds this threshold.
837	<	* (The value of this field is always <tt>(int)(capacity *
318	<	* loadFactor)</tt>.)
836	>	* Finds or adds a node.
837	>	* @return null if added
838		*/
839	<	transient int threshold;
839	>	final TreeNode<K,V> putTreeNode(int h, Object k, V v) {
840	>	Class<?> cc = comparableClassFor(k);
841	>	TreeNode<K,V> pp = root, p = null;
842	>	int dir = 0;
843	>	while (pp != null) { // find existing node or leaf to insert at
844	>	int ph; Object pk;
845	>	p = pp;
846	>	if ((ph = p.hash) != h)
847	>	dir = (h < ph) ? -1 : 1;
848	>	else if ((pk = p.key) == k || k.equals(pk))
849	>	return p;
850	>	else if (cc == null || comparableClassFor(pk) != cc ||
851	>	(dir = ((Comparable<Object>)k).compareTo(pk)) == 0) {
852	>	TreeNode<K,V> r, pr;
853	>	if ((pr = p.right) != null && h >= pr.hash &&
854	>	(r = getTreeNode(h, k, pr, cc)) != null)
855	>	return r;
856	>	else // continue left
857	>	dir = -1;
858	>	}
859	>	pp = (dir > 0) ? p.right : p.left;
860	>	}
861	>
862	>	TreeNode<K,V> f = first;
863	>	TreeNode<K,V> x = first = new TreeNode<K,V>(h, k, v, f, p);
864	>	if (p == null)
865	>	root = x;
866	>	else { // attach and rebalance; adapted from CLR
867	>	TreeNode<K,V> xp, xpp;
868	>	if (f != null)
869	>	f.prev = x;
870	>	if (dir <= 0)
871	>	p.left = x;
872	>	else
873	>	p.right = x;
874	>	x.red = true;
875	>	while (x != null && (xp = x.parent) != null && xp.red &&
876	>	(xpp = xp.parent) != null) {
877	>	TreeNode<K,V> xppl = xpp.left;
878	>	if (xp == xppl) {
879	>	TreeNode<K,V> y = xpp.right;
880	>	if (y != null && y.red) {
881	>	y.red = false;
882	>	xp.red = false;
883	>	xpp.red = true;
884	>	x = xpp;
885	>	}
886	>	else {
887	>	if (x == xp.right) {
888	>	rotateLeft(x = xp);
889	>	xpp = (xp = x.parent) == null ? null : xp.parent;
890	>	}
891	>	if (xp != null) {
892	>	xp.red = false;
893	>	if (xpp != null) {
894	>	xpp.red = true;
895	>	rotateRight(xpp);
896	>	}
897	>	}
898	>	}
899	>	}
900	>	else {
901	>	TreeNode<K,V> y = xppl;
902	>	if (y != null && y.red) {
903	>	y.red = false;
904	>	xp.red = false;
905	>	xpp.red = true;
906	>	x = xpp;
907	>	}
908	>	else {
909	>	if (x == xp.left) {
910	>	rotateRight(x = xp);
911	>	xpp = (xp = x.parent) == null ? null : xp.parent;
912	>	}
913	>	if (xp != null) {
914	>	xp.red = false;
915	>	if (xpp != null) {
916	>	xpp.red = true;
917	>	rotateLeft(xpp);
918	>	}
919	>	}
920	>	}
921	>	}
922	>	}
923	>	TreeNode<K,V> r = root;
924	>	if (r != null && r.red)
925	>	r.red = false;
926	>	}
927	>	return null;
928	>	}
929
930		/**
931	<	* The load factor for the hash table.  Even though this value
932	<	* is same for all segments, it is replicated to avoid needing
933	<	* links to outer object.
934	<	* @serial
931	>	* Removes the given node, that must be present before this
932	>	* call.  This is messier than typical red-black deletion code
933	>	* because we cannot swap the contents of an interior node
934	>	* with a leaf successor that is pinned by "next" pointers
935	>	* that are accessible independently of lock. So instead we
936	>	* swap the tree linkages.
937		*/
938	<	final float loadFactor;
938	>	final void deleteTreeNode(TreeNode<K,V> p) {
939	>	TreeNode<K,V> next = (TreeNode<K,V>)p.next;
940	>	TreeNode<K,V> pred = p.prev;  // unlink traversal pointers
941	>	if (pred == null)
942	>	first = next;
943	>	else
944	>	pred.next = next;
945	>	if (next != null)
946	>	next.prev = pred;
947	>	TreeNode<K,V> replacement;
948	>	TreeNode<K,V> pl = p.left;
949	>	TreeNode<K,V> pr = p.right;
950	>	if (pl != null && pr != null) {
951	>	TreeNode<K,V> s = pr, sl;
952	>	while ((sl = s.left) != null) // find successor
953	>	s = sl;
954	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
955	>	TreeNode<K,V> sr = s.right;
956	>	TreeNode<K,V> pp = p.parent;
957	>	if (s == pr) { // p was s's direct parent
958	>	p.parent = s;
959	>	s.right = p;
960	>	}
961	>	else {
962	>	TreeNode<K,V> sp = s.parent;
963	>	if ((p.parent = sp) != null) {
964	>	if (s == sp.left)
965	>	sp.left = p;
966	>	else
967	>	sp.right = p;
968	>	}
969	>	if ((s.right = pr) != null)
970	>	pr.parent = s;
971	>	}
972	>	p.left = null;
973	>	if ((p.right = sr) != null)
974	>	sr.parent = p;
975	>	if ((s.left = pl) != null)
976	>	pl.parent = s;
977	>	if ((s.parent = pp) == null)
978	>	root = s;
979	>	else if (p == pp.left)
980	>	pp.left = s;
981	>	else
982	>	pp.right = s;
983	>	replacement = sr;
984	>	}
985	>	else
986	>	replacement = (pl != null) ? pl : pr;
987	>	TreeNode<K,V> pp = p.parent;
988	>	if (replacement == null) {
989	>	if (pp == null) {
990	>	root = null;
991	>	return;
992	>	}
993	>	replacement = p;
994	>	}
995	>	else {
996	>	replacement.parent = pp;
997	>	if (pp == null)
998	>	root = replacement;
999	>	else if (p == pp.left)
1000	>	pp.left = replacement;
1001	>	else
1002	>	pp.right = replacement;
1003	>	p.left = p.right = p.parent = null;
1004	>	}
1005	>	if (!p.red) { // rebalance, from CLR
1006	>	TreeNode<K,V> x = replacement;
1007	>	while (x != null) {
1008	>	TreeNode<K,V> xp, xpl;
1009	>	if (x.red || (xp = x.parent) == null) {
1010	>	x.red = false;
1011	>	break;
1012	>	}
1013	>	if (x == (xpl = xp.left)) {
1014	>	TreeNode<K,V> sib = xp.right;
1015	>	if (sib != null && sib.red) {
1016	>	sib.red = false;
1017	>	xp.red = true;
1018	>	rotateLeft(xp);
1019	>	sib = (xp = x.parent) == null ? null : xp.right;
1020	>	}
1021	>	if (sib == null)
1022	>	x = xp;
1023	>	else {
1024	>	TreeNode<K,V> sl = sib.left, sr = sib.right;
1025	>	if ((sr == null || !sr.red) &&
1026	>	(sl == null || !sl.red)) {
1027	>	sib.red = true;
1028	>	x = xp;
1029	>	}
1030	>	else {
1031	>	if (sr == null || !sr.red) {
1032	>	if (sl != null)
1033	>	sl.red = false;
1034	>	sib.red = true;
1035	>	rotateRight(sib);
1036	>	sib = (xp = x.parent) == null ?
1037	>	null : xp.right;
1038	>	}
1039	>	if (sib != null) {
1040	>	sib.red = (xp == null) ? false : xp.red;
1041	>	if ((sr = sib.right) != null)
1042	>	sr.red = false;
1043	>	}
1044	>	if (xp != null) {
1045	>	xp.red = false;
1046	>	rotateLeft(xp);
1047	>	}
1048	>	x = root;
1049	>	}
1050	>	}
1051	>	}
1052	>	else { // symmetric
1053	>	TreeNode<K,V> sib = xpl;
1054	>	if (sib != null && sib.red) {
1055	>	sib.red = false;
1056	>	xp.red = true;
1057	>	rotateRight(xp);
1058	>	sib = (xp = x.parent) == null ? null : xp.left;
1059	>	}
1060	>	if (sib == null)
1061	>	x = xp;
1062	>	else {
1063	>	TreeNode<K,V> sl = sib.left, sr = sib.right;
1064	>	if ((sl == null || !sl.red) &&
1065	>	(sr == null || !sr.red)) {
1066	>	sib.red = true;
1067	>	x = xp;
1068	>	}
1069	>	else {
1070	>	if (sl == null || !sl.red) {
1071	>	if (sr != null)
1072	>	sr.red = false;
1073	>	sib.red = true;
1074	>	rotateLeft(sib);
1075	>	sib = (xp = x.parent) == null ?
1076	>	null : xp.left;
1077	>	}
1078	>	if (sib != null) {
1079	>	sib.red = (xp == null) ? false : xp.red;
1080	>	if ((sl = sib.left) != null)
1081	>	sl.red = false;
1082	>	}
1083	>	if (xp != null) {
1084	>	xp.red = false;
1085	>	rotateRight(xp);
1086	>	}
1087	>	x = root;
1088	>	}
1089	>	}
1090	>	}
1091	>	}
1092	>	}
1093	>	if (p == replacement && (pp = p.parent) != null) {
1094	>	if (p == pp.left) // detach pointers
1095	>	pp.left = null;
1096	>	else if (p == pp.right)
1097	>	pp.right = null;
1098	>	p.parent = null;
1099	>	}
1100	>	}
1101	>	}
1102
1103	<	Segment(float lf, int threshold, HashEntry<K,V>[] tab) {
1104	<	this.loadFactor = lf;
1105	<	this.threshold = threshold;
1106	<	this.table = tab;
1103	>	/* ---------------- Collision reduction methods -------------- */
1104	>
1105	>	/**
1106	>	* Spreads higher bits to lower, and also forces top bit to 0.
1107	>	* Because the table uses power-of-two masking, sets of hashes
1108	>	* that vary only in bits above the current mask will always
1109	>	* collide. (Among known examples are sets of Float keys holding
1110	>	* consecutive whole numbers in small tables.)  To counter this,
1111	>	* we apply a transform that spreads the impact of higher bits
1112	>	* downward. There is a tradeoff between speed, utility, and
1113	>	* quality of bit-spreading. Because many common sets of hashes
1114	>	* are already reasonably distributed across bits (so don't benefit
1115	>	* from spreading), and because we use trees to handle large sets
1116	>	* of collisions in bins, we don't need excessively high quality.
1117	>	*/
1118	>	private static final int spread(int h) {
1119	>	h ^= (h >>> 18) ^ (h >>> 12);
1120	>	return (h ^ (h >>> 10)) & HASH_BITS;
1121	>	}
1122	>
1123	>	/**
1124	>	* Replaces a list bin with a tree bin if key is comparable.  Call
1125	>	* only when locked.
1126	>	*/
1127	>	private final void replaceWithTreeBin(Node<K,V>[] tab, int index, Object key) {
1128	>	if (tab != null && comparableClassFor(key) != null) {
1129	>	TreeBin<K,V> t = new TreeBin<K,V>();
1130	>	for (Node<K,V> e = tabAt(tab, index); e != null; e = e.next)
1131	>	t.putTreeNode(e.hash, e.key, e.val);
1132	>	setTabAt(tab, index, new Node<K,V>(MOVED, t, null, null));
1133		}
1134	+	}
1135
1136	<	final V put(K key, int hash, V value, boolean onlyIfAbsent) {
1137	<	HashEntry<K,V> node = tryLock() ? null :
1138	<	scanAndLockForPut(key, hash, value);
1139	<	V oldValue;
1140	<	try {
1141	<	HashEntry<K,V>[] tab = table;
1142	<	int index = (tab.length - 1) & hash;
1143	<	HashEntry<K,V> first = entryAt(tab, index);
1144	<	for (HashEntry<K,V> e = first;;) {
1145	<	if (e != null) {
1146	<	K k;
1147	<	if ((k = e.key) == key ||
1148	<	(e.hash == hash && key.equals(k))) {
1149	<	oldValue = e.value;
1150	<	if (!onlyIfAbsent) {
1151	<	e.value = value;
1152	<	++modCount;
1136	>	/* ---------------- Internal access and update methods -------------- */
1137	>
1138	>	/** Implementation for get and containsKey */
1139	>	private final V internalGet(Object k) {
1140	>	int h = spread(k.hashCode());
1141	>	V v = null;
1142	>	Node<K,V>[] tab; Node<K,V> e;
1143	>	if ((tab = table) != null &&
1144	>	(e = tabAt(tab, (tab.length - 1) & h)) != null) {
1145	>	for (;;) {
1146	>	int eh; Object ek;
1147	>	if ((eh = e.hash) < 0) {
1148	>	if ((ek = e.key) instanceof TreeBin) { // search TreeBin
1149	>	v = ((TreeBin<K,V>)ek).getValue(h, k);
1150	>	break;
1151	>	}
1152	>	else if (!(ek instanceof Node[]) ||    // try new table
1153	>	(e = tabAt(tab = (Node<K,V>[])ek,
1154	>	(tab.length - 1) & h)) == null)
1155	>	break;
1156	>	}
1157	>	else if (eh == h && ((ek = e.key) == k || k.equals(ek))) {
1158	>	v = e.val;
1159	>	break;
1160	>	}
1161	>	else if ((e = e.next) == null)
1162	>	break;
1163	>	}
1164	>	}
1165	>	return v;
1166	>	}
1167	>
1168	>	/**
1169	>	* Implementation for the four public remove/replace methods:
1170	>	* Replaces node value with v, conditional upon match of cv if
1171	>	* non-null.  If resulting value is null, delete.
1172	>	*/
1173	>	private final V internalReplace(Object k, V v, Object cv) {
1174	>	int h = spread(k.hashCode());
1175	>	V oldVal = null;
1176	>	for (Node<K,V>[] tab = table;;) {
1177	>	Node<K,V> f; int i, fh; Object fk;
1178	>	if (tab == null ||
1179	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1180	>	break;
1181	>	else if ((fh = f.hash) < 0) {
1182	>	if ((fk = f.key) instanceof TreeBin) {
1183	>	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1184	>	long stamp = t.writeLock();
1185	>	boolean validated = false;
1186	>	boolean deleted = false;
1187	>	try {
1188	>	if (tabAt(tab, i) == f) {
1189	>	validated = true;
1190	>	Class<?> cc = comparableClassFor(k);
1191	>	TreeNode<K,V> p = t.getTreeNode(h, k, t.root, cc);
1192	>	if (p != null) {
1193	>	V pv = p.val;
1194	>	if (cv == null || cv == pv || cv.equals(pv)) {
1195	>	oldVal = pv;
1196	>	if (v != null)
1197	>	p.val = v;
1198	>	else {
1199	>	deleted = true;
1200	>	t.deleteTreeNode(p);
1201	>	}
1202	>	}
1203		}
354	–	break;
1204		}
1205	<	e = e.next;
1205	>	} finally {
1206	>	t.unlockWrite(stamp);
1207		}
1208	<	else {
1209	<	if (node != null)
1210	<	node.setNext(first);
361	<	else
362	<	node = new HashEntry<K,V>(hash, key, value, first);
363	<	int c = count + 1;
364	<	if (c > threshold && tab.length < MAXIMUM_CAPACITY)
365	<	rehash(node);
366	<	else
367	<	setEntryAt(tab, index, node);
368	<	++modCount;
369	<	count = c;
370	<	oldValue = null;
1208	>	if (validated) {
1209	>	if (deleted)
1210	>	addCount(-1L, -1);
1211		break;
1212		}
1213		}
1214	<	} finally {
1215	<	unlock();
1214	>	else
1215	>	tab = (Node<K,V>[])fk;
1216	>	}
1217	>	else {
1218	>	boolean validated = false;
1219	>	boolean deleted = false;
1220	>	synchronized (f) {
1221	>	if (tabAt(tab, i) == f) {
1222	>	validated = true;
1223	>	for (Node<K,V> e = f, pred = null;;) {
1224	>	Object ek;
1225	>	if (e.hash == h &&
1226	>	((ek = e.key) == k || k.equals(ek))) {
1227	>	V ev = e.val;
1228	>	if (cv == null || cv == ev || cv.equals(ev)) {
1229	>	oldVal = ev;
1230	>	if (v != null)
1231	>	e.val = v;
1232	>	else {
1233	>	deleted = true;
1234	>	Node<K,V> en = e.next;
1235	>	if (pred != null)
1236	>	pred.next = en;
1237	>	else
1238	>	setTabAt(tab, i, en);
1239	>	}
1240	>	}
1241	>	break;
1242	>	}
1243	>	pred = e;
1244	>	if ((e = e.next) == null)
1245	>	break;
1246	>	}
1247	>	}
1248	>	}
1249	>	if (validated) {
1250	>	if (deleted)
1251	>	addCount(-1L, -1);
1252	>	break;
1253	>	}
1254		}
377	–	return oldValue;
1255		}
1256	+	return oldVal;
1257	+	}
1258
1259	<	/**
1260	<	* Doubles size of table and repacks entries, also adding the
1261	<	* given node to new table
1262	<	*/
1263	<	@SuppressWarnings("unchecked")
1264	<	private void rehash(HashEntry<K,V> node) {
1265	<	/*
1266	<	* Reclassify nodes in each list to new table.  Because we
1267	<	* are using power-of-two expansion, the elements from
1268	<	* each bin must either stay at same index, or move with a
1269	<	* power of two offset. We eliminate unnecessary node
1270	<	* creation by catching cases where old nodes can be
1271	<	* reused because their next fields won't change.
1272	<	* Statistically, at the default threshold, only about
1273	<	* one-sixth of them need cloning when a table
1274	<	* doubles. The nodes they replace will be garbage
1275	<	* collectable as soon as they are no longer referenced by
1276	<	* any reader thread that may be in the midst of
1277	<	* concurrently traversing table. Entry accesses use plain
1278	<	* array indexing because they are followed by volatile
1279	<	* table write.
1280	<	*/
1281	<	HashEntry<K,V>[] oldTable = table;
1282	<	int oldCapacity = oldTable.length;
1283	<	int newCapacity = oldCapacity << 1;
1284	<	threshold = (int)(newCapacity * loadFactor);
1285	<	HashEntry<K,V>[] newTable =
1286	<	(HashEntry<K,V>[]) new HashEntry[newCapacity];
1287	<	int sizeMask = newCapacity - 1;
1288	<	for (int i = 0; i < oldCapacity ; i++) {
1289	<	HashEntry<K,V> e = oldTable[i];
1290	<	if (e != null) {
1291	<	HashEntry<K,V> next = e.next;
1292	<	int idx = e.hash & sizeMask;
1293	<	if (next == null)   //  Single node on list
1294	<	newTable[idx] = e;
1295	<	else { // Reuse consecutive sequence at same slot
1296	<	HashEntry<K,V> lastRun = e;
1297	<	int lastIdx = idx;
1298	<	for (HashEntry<K,V> last = next;
1299	<	last != null;
1300	<	last = last.next) {
1301	<	int k = last.hash & sizeMask;
1302	<	if (k != lastIdx) {
1303	<	lastIdx = k;
425	<	lastRun = last;
426	<	}
427	<	}
428	<	newTable[lastIdx] = lastRun;
429	<	// Clone remaining nodes
430	<	for (HashEntry<K,V> p = e; p != lastRun; p = p.next) {
431	<	V v = p.value;
432	<	int h = p.hash;
433	<	int k = h & sizeMask;
434	<	HashEntry<K,V> n = newTable[k];
435	<	newTable[k] = new HashEntry<K,V>(h, p.key, v, n);
1259	>	/*
1260	>	* Internal versions of insertion methods
1261	>	* All have the same basic structure as the first (internalPut):
1262	>	*  1. If table uninitialized, create
1263	>	*  2. If bin empty, try to CAS new node
1264	>	*  3. If bin stale, use new table
1265	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1266	>	*  5. Lock and validate; if valid, scan and add or update
1267	>	*
1268	>	* The putAll method differs mainly in attempting to pre-allocate
1269	>	* enough table space, and also more lazily performs count updates
1270	>	* and checks.
1271	>	*
1272	>	* Most of the function-accepting methods can't be factored nicely
1273	>	* because they require different functional forms, so instead
1274	>	* sprawl out similar mechanics.
1275	>	*/
1276	>
1277	>	/** Implementation for put and putIfAbsent */
1278	>	private final V internalPut(K k, V v, boolean onlyIfAbsent) {
1279	>	if (k == null || v == null) throw new NullPointerException();
1280	>	int h = spread(k.hashCode());
1281	>	int len = 0;
1282	>	for (Node<K,V>[] tab = table;;) {
1283	>	int i, fh; Node<K,V> f; Object fk;
1284	>	if (tab == null)
1285	>	tab = initTable();
1286	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1287	>	if (casTabAt(tab, i, null, new Node<K,V>(h, k, v, null)))
1288	>	break;                   // no lock when adding to empty bin
1289	>	}
1290	>	else if ((fh = f.hash) < 0) {
1291	>	if ((fk = f.key) instanceof TreeBin) {
1292	>	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1293	>	long stamp = t.writeLock();
1294	>	V oldVal = null;
1295	>	try {
1296	>	if (tabAt(tab, i) == f) {
1297	>	len = 2;
1298	>	TreeNode<K,V> p = t.putTreeNode(h, k, v);
1299	>	if (p != null) {
1300	>	oldVal = p.val;
1301	>	if (!onlyIfAbsent)
1302	>	p.val = v;
1303	>	}
1304		}
1305	+	} finally {
1306	+	t.unlockWrite(stamp);
1307	+	}
1308	+	if (len != 0) {
1309	+	if (oldVal != null)
1310	+	return oldVal;
1311	+	break;
1312		}
1313		}
1314	+	else
1315	+	tab = (Node<K,V>[])fk;
1316	+	}
1317	+	else {
1318	+	V oldVal = null;
1319	+	synchronized (f) {
1320	+	if (tabAt(tab, i) == f) {
1321	+	len = 1;
1322	+	for (Node<K,V> e = f;; ++len) {
1323	+	Object ek;
1324	+	if (e.hash == h &&
1325	+	((ek = e.key) == k || k.equals(ek))) {
1326	+	oldVal = e.val;
1327	+	if (!onlyIfAbsent)
1328	+	e.val = v;
1329	+	break;
1330	+	}
1331	+	Node<K,V> last = e;
1332	+	if ((e = e.next) == null) {
1333	+	last.next = new Node<K,V>(h, k, v, null);
1334	+	if (len > TREE_THRESHOLD)
1335	+	replaceWithTreeBin(tab, i, k);
1336	+	break;
1337	+	}
1338	+	}
1339	+	}
1340	+	}
1341	+	if (len != 0) {
1342	+	if (oldVal != null)
1343	+	return oldVal;
1344	+	break;
1345	+	}
1346		}
440	–	int nodeIndex = node.hash & sizeMask; // add the new node
441	–	node.setNext(newTable[nodeIndex]);
442	–	newTable[nodeIndex] = node;
443	–	table = newTable;
1347		}
1348	+	addCount(1L, len);
1349	+	return null;
1350	+	}
1351
1352	<	/**
1353	<	* Scans for a node containing given key while trying to
1354	<	* acquire lock, creating and returning one if not found. Upon
1355	<	* return, guarantees that lock is held. Unlike in most
1356	<	* methods, calls to method equals are not screened: Since
1357	<	* traversal speed doesn't matter, we might as well help warm
1358	<	* up the associated code and accesses as well.
1359	<	*
1360	<	* @return a new node if key not found, else null
1361	<	*/
1362	<	private HashEntry<K,V> scanAndLockForPut(K key, int hash, V value) {
1363	<	HashEntry<K,V> first = entryForHash(this, hash);
1364	<	HashEntry<K,V> e = first;
1365	<	HashEntry<K,V> node = null;
1366	<	int retries = -1; // negative while locating node
1367	<	while (!tryLock()) {
1368	<	HashEntry<K,V> f; // to recheck first below
1369	<	if (retries < 0) {
1370	<	if (e == null) {
1371	<	if (node == null) // speculatively create node
1372	<	node = new HashEntry<K,V>(hash, key, value, null);
1373	<	retries = 0;
1352	>	/** Implementation for computeIfAbsent */
1353	>	private final V internalComputeIfAbsent(K k, Function<? super K, ? extends V> mf) {
1354	>	if (k == null || mf == null)
1355	>	throw new NullPointerException();
1356	>	int h = spread(k.hashCode());
1357	>	V val = null;
1358	>	int len = 0;
1359	>	for (Node<K,V>[] tab = table;;) {
1360	>	Node<K,V> f; int i; Object fk;
1361	>	if (tab == null)
1362	>	tab = initTable();
1363	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1364	>	Node<K,V> node = new Node<K,V>(h, k, null, null);
1365	>	synchronized (node) {
1366	>	if (casTabAt(tab, i, null, node)) {
1367	>	len = 1;
1368	>	try {
1369	>	if ((val = mf.apply(k)) != null)
1370	>	node.val = val;
1371	>	} finally {
1372	>	if (val == null)
1373	>	setTabAt(tab, i, null);
1374	>	}
1375		}
469	–	else if (key.equals(e.key))
470	–	retries = 0;
471	–	else
472	–	e = e.next;
1376		}
1377	<	else if (++retries > MAX_SCAN_RETRIES) {
475	<	lock();
1377	>	if (len != 0)
1378		break;
1379	+	}
1380	+	else if (f.hash < 0) {
1381	+	if ((fk = f.key) instanceof TreeBin) {
1382	+	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1383	+	long stamp = t.writeLock();
1384	+	boolean added = false;
1385	+	try {
1386	+	if (tabAt(tab, i) == f) {
1387	+	len = 2;
1388	+	Class<?> cc = comparableClassFor(k);
1389	+	TreeNode<K,V> p = t.getTreeNode(h, k, t.root, cc);
1390	+	if (p != null)
1391	+	val = p.val;
1392	+	else if ((val = mf.apply(k)) != null) {
1393	+	added = true;
1394	+	t.putTreeNode(h, k, val);
1395	+	}
1396	+	}
1397	+	} finally {
1398	+	t.unlockWrite(stamp);
1399	+	}
1400	+	if (len != 0) {
1401	+	if (!added)
1402	+	return val;
1403	+	break;
1404	+	}
1405	+	}
1406	+	else
1407	+	tab = (Node<K,V>[])fk;
1408	+	}
1409	+	else {
1410	+	boolean added = false;
1411	+	synchronized (f) {
1412	+	if (tabAt(tab, i) == f) {
1413	+	len = 1;
1414	+	for (Node<K,V> e = f;; ++len) {
1415	+	Object ek; V ev;
1416	+	if (e.hash == h &&
1417	+	((ek = e.key) == k || k.equals(ek))) {
1418	+	val = e.val;
1419	+	break;
1420	+	}
1421	+	Node<K,V> last = e;
1422	+	if ((e = e.next) == null) {
1423	+	if ((val = mf.apply(k)) != null) {
1424	+	added = true;
1425	+	last.next = new Node<K,V>(h, k, val, null);
1426	+	if (len > TREE_THRESHOLD)
1427	+	replaceWithTreeBin(tab, i, k);
1428	+	}
1429	+	break;
1430	+	}
1431	+	}
1432	+	}
1433		}
1434	<	else if ((retries & 1) == 0 &&
1435	<	(f = entryForHash(this, hash)) != first) {
1436	<	e = first = f; // re-traverse if entry changed
1437	<	retries = -1;
1434	>	if (len != 0) {
1435	>	if (!added)
1436	>	return val;
1437	>	break;
1438		}
1439		}
484	–	return node;
1440		}
1441	+	if (val != null)
1442	+	addCount(1L, len);
1443	+	return val;
1444	+	}
1445
1446	<	/**
1447	<	* Scans for a node containing the given key while trying to
1448	<	* acquire lock for a remove or replace operation. Upon
1449	<	* return, guarantees that lock is held.  Note that we must
1450	<	* lock even if the key is not found, to ensure sequential
1451	<	* consistency of updates.
1452	<	*/
1453	<	private void scanAndLock(Object key, int hash) {
1454	<	// similar to but simpler than scanAndLockForPut
1455	<	HashEntry<K,V> first = entryForHash(this, hash);
1456	<	HashEntry<K,V> e = first;
1457	<	int retries = -1;
1458	<	while (!tryLock()) {
1459	<	HashEntry<K,V> f;
1460	<	if (retries < 0) {
1461	<	if (e == null || key.equals(e.key))
1462	<	retries = 0;
1463	<	else
1464	<	e = e.next;
1446	>	/** Implementation for compute */
1447	>	private final V internalCompute(K k, boolean onlyIfPresent,
1448	>	BiFunction<? super K, ? super V, ? extends V> mf) {
1449	>	if (k == null || mf == null)
1450	>	throw new NullPointerException();
1451	>	int h = spread(k.hashCode());
1452	>	V val = null;
1453	>	int delta = 0;
1454	>	int len = 0;
1455	>	for (Node<K,V>[] tab = table;;) {
1456	>	Node<K,V> f; int i, fh; Object fk;
1457	>	if (tab == null)
1458	>	tab = initTable();
1459	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1460	>	if (onlyIfPresent)
1461	>	break;
1462	>	Node<K,V> node = new Node<K,V>(h, k, null, null);
1463	>	synchronized (node) {
1464	>	if (casTabAt(tab, i, null, node)) {
1465	>	try {
1466	>	len = 1;
1467	>	if ((val = mf.apply(k, null)) != null) {
1468	>	node.val = val;
1469	>	delta = 1;
1470	>	}
1471	>	} finally {
1472	>	if (delta == 0)
1473	>	setTabAt(tab, i, null);
1474	>	}
1475	>	}
1476		}
1477	<	else if (++retries > MAX_SCAN_RETRIES) {
508	<	lock();
1477	>	if (len != 0)
1478		break;
1479	+	}
1480	+	else if ((fh = f.hash) < 0) {
1481	+	if ((fk = f.key) instanceof TreeBin) {
1482	+	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1483	+	long stamp = t.writeLock();
1484	+	try {
1485	+	if (tabAt(tab, i) == f) {
1486	+	len = 2;
1487	+	Class<?> cc = comparableClassFor(k);
1488	+	TreeNode<K,V> p = t.getTreeNode(h, k, t.root, cc);
1489	+	if (p != null || !onlyIfPresent) {
1490	+	V pv = (p == null) ? null : p.val;
1491	+	if ((val = mf.apply(k, pv)) != null) {
1492	+	if (p != null)
1493	+	p.val = val;
1494	+	else {
1495	+	delta = 1;
1496	+	t.putTreeNode(h, k, val);
1497	+	}
1498	+	}
1499	+	else if (p != null) {
1500	+	delta = -1;
1501	+	t.deleteTreeNode(p);
1502	+	}
1503	+	}
1504	+	}
1505	+	} finally {
1506	+	t.unlockWrite(stamp);
1507	+	}
1508	+	if (len != 0)
1509	+	break;
1510		}
1511	<	else if ((retries & 1) == 0 &&
1512	<	(f = entryForHash(this, hash)) != first) {
1513	<	e = first = f;
1514	<	retries = -1;
1511	>	else
1512	>	tab = (Node<K,V>[])fk;
1513	>	}
1514	>	else {
1515	>	synchronized (f) {
1516	>	if (tabAt(tab, i) == f) {
1517	>	len = 1;
1518	>	for (Node<K,V> e = f, pred = null;; ++len) {
1519	>	Object ek;
1520	>	if (e.hash == h &&
1521	>	((ek = e.key) == k || k.equals(ek))) {
1522	>	val = mf.apply(k, e.val);
1523	>	if (val != null)
1524	>	e.val = val;
1525	>	else {
1526	>	delta = -1;
1527	>	Node<K,V> en = e.next;
1528	>	if (pred != null)
1529	>	pred.next = en;
1530	>	else
1531	>	setTabAt(tab, i, en);
1532	>	}
1533	>	break;
1534	>	}
1535	>	pred = e;
1536	>	if ((e = e.next) == null) {
1537	>	if (!onlyIfPresent &&
1538	>	(val = mf.apply(k, null)) != null) {
1539	>	pred.next = new Node<K,V>(h, k, val, null);
1540	>	delta = 1;
1541	>	if (len > TREE_THRESHOLD)
1542	>	replaceWithTreeBin(tab, i, k);
1543	>	}
1544	>	break;
1545	>	}
1546	>	}
1547	>	}
1548		}
1549	+	if (len != 0)
1550	+	break;
1551		}
1552		}
1553	+	if (delta != 0)
1554	+	addCount((long)delta, len);
1555	+	return val;
1556	+	}
1557
1558	<	/**
1559	<	* Remove; match on key only if value null, else match both.
1560	<	*/
1561	<	final V remove(Object key, int hash, Object value) {
1562	<	if (!tryLock())
1563	<	scanAndLock(key, hash);
1564	<	V oldValue = null;
1565	<	try {
1566	<	HashEntry<K,V>[] tab = table;
1567	<	int index = (tab.length - 1) & hash;
1568	<	HashEntry<K,V> e = entryAt(tab, index);
1569	<	HashEntry<K,V> pred = null;
1570	<	while (e != null) {
1571	<	K k;
1572	<	HashEntry<K,V> next = e.next;
1573	<	if ((k = e.key) == key ||
1574	<	(e.hash == hash && key.equals(k))) {
1575	<	V v = e.value;
1576	<	if (value == null || value == v || value.equals(v)) {
1577	<	if (pred == null)
1578	<	setEntryAt(tab, index, next);
1579	<	else
1580	<	pred.setNext(next);
1581	<	++modCount;
1582	<	--count;
1583	<	oldValue = v;
1558	>	/** Implementation for merge */
1559	>	private final V internalMerge(K k, V v,
1560	>	BiFunction<? super V, ? super V, ? extends V> mf) {
1561	>	if (k == null || v == null || mf == null)
1562	>	throw new NullPointerException();
1563	>	int h = spread(k.hashCode());
1564	>	V val = null;
1565	>	int delta = 0;
1566	>	int len = 0;
1567	>	for (Node<K,V>[] tab = table;;) {
1568	>	int i; Node<K,V> f; Object fk;
1569	>	if (tab == null)
1570	>	tab = initTable();
1571	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1572	>	if (casTabAt(tab, i, null, new Node<K,V>(h, k, v, null))) {
1573	>	delta = 1;
1574	>	val = v;
1575	>	break;
1576	>	}
1577	>	}
1578	>	else if (f.hash < 0) {
1579	>	if ((fk = f.key) instanceof TreeBin) {
1580	>	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1581	>	long stamp = t.writeLock();
1582	>	try {
1583	>	if (tabAt(tab, i) == f) {
1584	>	len = 2;
1585	>	Class<?> cc = comparableClassFor(k);
1586	>	TreeNode<K,V> p = t.getTreeNode(h, k, t.root, cc);
1587	>	val = (p == null) ? v : mf.apply(p.val, v);
1588	>	if (val != null) {
1589	>	if (p != null)
1590	>	p.val = val;
1591	>	else {
1592	>	delta = 1;
1593	>	t.putTreeNode(h, k, val);
1594	>	}
1595	>	}
1596	>	else if (p != null) {
1597	>	delta = -1;
1598	>	t.deleteTreeNode(p);
1599	>	}
1600		}
1601	+	} finally {
1602	+	t.unlockWrite(stamp);
1603	+	}
1604	+	if (len != 0)
1605		break;
1606	+	}
1607	+	else
1608	+	tab = (Node<K,V>[])fk;
1609	+	}
1610	+	else {
1611	+	synchronized (f) {
1612	+	if (tabAt(tab, i) == f) {
1613	+	len = 1;
1614	+	for (Node<K,V> e = f, pred = null;; ++len) {
1615	+	Object ek;
1616	+	if (e.hash == h &&
1617	+	((ek = e.key) == k || k.equals(ek))) {
1618	+	val = mf.apply(e.val, v);
1619	+	if (val != null)
1620	+	e.val = val;
1621	+	else {
1622	+	delta = -1;
1623	+	Node<K,V> en = e.next;
1624	+	if (pred != null)
1625	+	pred.next = en;
1626	+	else
1627	+	setTabAt(tab, i, en);
1628	+	}
1629	+	break;
1630	+	}
1631	+	pred = e;
1632	+	if ((e = e.next) == null) {
1633	+	delta = 1;
1634	+	val = v;
1635	+	pred.next = new Node<K,V>(h, k, val, null);
1636	+	if (len > TREE_THRESHOLD)
1637	+	replaceWithTreeBin(tab, i, k);
1638	+	break;
1639	+	}
1640	+	}
1641		}
548	–	pred = e;
549	–	e = next;
1642		}
1643	<	} finally {
1644	<	unlock();
1643	>	if (len != 0)
1644	>	break;
1645		}
554	–	return oldValue;
1646		}
1647	+	if (delta != 0)
1648	+	addCount((long)delta, len);
1649	+	return val;
1650	+	}
1651	+
1652	+	/** Implementation for putAll */
1653	+	private final void internalPutAll(Map<? extends K, ? extends V> m) {
1654	+	tryPresize(m.size());
1655	+	long delta = 0L;     // number of uncommitted additions
1656	+	boolean npe = false; // to throw exception on exit for nulls
1657	+	try {                // to clean up counts on other exceptions
1658	+	for (Map.Entry<?, ? extends V> entry : m.entrySet()) {
1659	+	Object k; V v;
1660	+	if (entry == null || (k = entry.getKey()) == null ||
1661	+	(v = entry.getValue()) == null) {
1662	+	npe = true;
1663	+	break;
1664	+	}
1665	+	int h = spread(k.hashCode());
1666	+	for (Node<K,V>[] tab = table;;) {
1667	+	int i; Node<K,V> f; int fh; Object fk;
1668	+	if (tab == null)
1669	+	tab = initTable();
1670	+	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1671	+	if (casTabAt(tab, i, null, new Node<K,V>(h, k, v, null))) {
1672	+	++delta;
1673	+	break;
1674	+	}
1675	+	}
1676	+	else if ((fh = f.hash) < 0) {
1677	+	if ((fk = f.key) instanceof TreeBin) {
1678	+	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1679	+	long stamp = t.writeLock();
1680	+	boolean validated = false;
1681	+	try {
1682	+	if (tabAt(tab, i) == f) {
1683	+	validated = true;
1684	+	Class<?> cc = comparableClassFor(k);
1685	+	TreeNode<K,V> p = t.getTreeNode(h, k,
1686	+	t.root, cc);
1687	+	if (p != null)
1688	+	p.val = v;
1689	+	else {
1690	+	++delta;
1691	+	t.putTreeNode(h, k, v);
1692	+	}
1693	+	}
1694	+	} finally {
1695	+	t.unlockWrite(stamp);
1696	+	}
1697	+	if (validated)
1698	+	break;
1699	+	}
1700	+	else
1701	+	tab = (Node<K,V>[])fk;
1702	+	}
1703	+	else {
1704	+	int len = 0;
1705	+	synchronized (f) {
1706	+	if (tabAt(tab, i) == f) {
1707	+	len = 1;
1708	+	for (Node<K,V> e = f;; ++len) {
1709	+	Object ek;
1710	+	if (e.hash == h &&
1711	+	((ek = e.key) == k || k.equals(ek))) {
1712	+	e.val = v;
1713	+	break;
1714	+	}
1715	+	Node<K,V> last = e;
1716	+	if ((e = e.next) == null) {
1717	+	++delta;
1718	+	last.next = new Node<K,V>(h, k, v, null);
1719	+	if (len > TREE_THRESHOLD)
1720	+	replaceWithTreeBin(tab, i, k);
1721	+	break;
1722	+	}
1723	+	}
1724	+	}
1725	+	}
1726	+	if (len != 0) {
1727	+	if (len > 1) {
1728	+	addCount(delta, len);
1729	+	delta = 0L;
1730	+	}
1731	+	break;
1732	+	}
1733	+	}
1734	+	}
1735	+	}
1736	+	} finally {
1737	+	if (delta != 0L)
1738	+	addCount(delta, 2);
1739	+	}
1740	+	if (npe)
1741	+	throw new NullPointerException();
1742	+	}
1743
1744	<	final boolean replace(K key, int hash, V oldValue, V newValue) {
1745	<	if (!tryLock())
1746	<	scanAndLock(key, hash);
1747	<	boolean replaced = false;
1748	<	try {
1749	<	HashEntry<K,V> e;
1750	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1751	<	K k;
1752	<	if ((k = e.key) == key ||
1753	<	(e.hash == hash && key.equals(k))) {
1754	<	if (oldValue.equals(e.value)) {
1755	<	e.value = newValue;
1756	<	++modCount;
1757	<	replaced = true;
1744	>	/**
1745	>	* Implementation for clear. Steps through each bin, removing all
1746	>	* nodes.
1747	>	*/
1748	>	private final void internalClear() {
1749	>	long delta = 0L; // negative number of deletions
1750	>	int i = 0;
1751	>	Node<K,V>[] tab = table;
1752	>	while (tab != null && i < tab.length) {
1753	>	Node<K,V> f = tabAt(tab, i);
1754	>	if (f == null)
1755	>	++i;
1756	>	else if (f.hash < 0) {
1757	>	Object fk;
1758	>	if ((fk = f.key) instanceof TreeBin) {
1759	>	TreeBin<K,V> t = (TreeBin<K,V>)fk;
1760	>	long stamp = t.writeLock();
1761	>	try {
1762	>	if (tabAt(tab, i) == f) {
1763	>	for (Node<K,V> p = t.first; p != null; p = p.next)
1764	>	--delta;
1765	>	t.first = null;
1766	>	t.root = null;
1767	>	++i;
1768		}
1769	<	break;
1769	>	} finally {
1770	>	t.unlockWrite(stamp);
1771	>	}
1772	>	}
1773	>	else
1774	>	tab = (Node<K,V>[])fk;
1775	>	}
1776	>	else {
1777	>	synchronized (f) {
1778	>	if (tabAt(tab, i) == f) {
1779	>	for (Node<K,V> e = f; e != null; e = e.next)
1780	>	--delta;
1781	>	setTabAt(tab, i, null);
1782	>	++i;
1783		}
1784		}
575	–	} finally {
576	–	unlock();
1785		}
578	–	return replaced;
1786		}
1787	+	if (delta != 0L)
1788	+	addCount(delta, -1);
1789	+	}
1790
1791	<	final V replace(K key, int hash, V value) {
1792	<	if (!tryLock())
1793	<	scanAndLock(key, hash);
1794	<	V oldValue = null;
1795	<	try {
1796	<	HashEntry<K,V> e;
1797	<	for (e = entryForHash(this, hash); e != null; e = e.next) {
1798	<	K k;
1799	<	if ((k = e.key) == key ||
1800	<	(e.hash == hash && key.equals(k))) {
1801	<	oldValue = e.value;
1802	<	e.value = value;
1803	<	++modCount;
1791	>	/* ---------------- Table Initialization and Resizing -------------- */
1792	>
1793	>	/**
1794	>	* Returns a power of two table size for the given desired capacity.
1795	>	* See Hackers Delight, sec 3.2
1796	>	*/
1797	>	private static final int tableSizeFor(int c) {
1798	>	int n = c - 1;
1799	>	n |= n >>> 1;
1800	>	n |= n >>> 2;
1801	>	n |= n >>> 4;
1802	>	n |= n >>> 8;
1803	>	n |= n >>> 16;
1804	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1805	>	}
1806	>
1807	>	/**
1808	>	* Initializes table, using the size recorded in sizeCtl.
1809	>	*/
1810	>	private final Node<K,V>[] initTable() {
1811	>	Node<K,V>[] tab; int sc;
1812	>	while ((tab = table) == null) {
1813	>	if ((sc = sizeCtl) < 0)
1814	>	Thread.yield(); // lost initialization race; just spin
1815	>	else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1816	>	try {
1817	>	if ((tab = table) == null) {
1818	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1819	>	table = tab = (Node<K,V>[])new Node[n];
1820	>	sc = n - (n >>> 2);
1821	>	}
1822	>	} finally {
1823	>	sizeCtl = sc;
1824	>	}
1825	>	break;
1826	>	}
1827	>	}
1828	>	return tab;
1829	>	}
1830	>
1831	>	/**
1832	>	* Adds to count, and if table is too small and not already
1833	>	* resizing, initiates transfer. If already resizing, helps
1834	>	* perform transfer if work is available.  Rechecks occupancy
1835	>	* after a transfer to see if another resize is already needed
1836	>	* because resizings are lagging additions.
1837	>	*
1838	>	* @param x the count to add
1839	>	* @param check if <0, don't check resize, if <= 1 only check if uncontended
1840	>	*/
1841	>	private final void addCount(long x, int check) {
1842	>	Cell[] as; long b, s;
1843	>	if ((as = counterCells) != null ||
1844	>	!U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
1845	>	Cell a; long v; int m;
1846	>	boolean uncontended = true;
1847	>	if (as == null || (m = as.length - 1) < 0 ||
1848	>	(a = as[ThreadLocalRandom.getProbe() & m]) == null ||
1849	>	!(uncontended =
1850	>	U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
1851	>	fullAddCount(x, uncontended);
1852	>	return;
1853	>	}
1854	>	if (check <= 1)
1855	>	return;
1856	>	s = sumCount();
1857	>	}
1858	>	if (check >= 0) {
1859	>	Node<K,V>[] tab, nt; int sc;
1860	>	while (s >= (long)(sc = sizeCtl) && (tab = table) != null &&
1861	>	tab.length < MAXIMUM_CAPACITY) {
1862	>	if (sc < 0) {
1863	>	if (sc == -1 || transferIndex <= transferOrigin ||
1864	>	(nt = nextTable) == null)
1865		break;
1866	+	if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
1867	+	transfer(tab, nt);
1868	+	}
1869	+	else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
1870	+	transfer(tab, null);
1871	+	s = sumCount();
1872	+	}
1873	+	}
1874	+	}
1875	+
1876	+	/**
1877	+	* Tries to presize table to accommodate the given number of elements.
1878	+	*
1879	+	* @param size number of elements (doesn't need to be perfectly accurate)
1880	+	*/
1881	+	private final void tryPresize(int size) {
1882	+	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1883	+	tableSizeFor(size + (size >>> 1) + 1);
1884	+	int sc;
1885	+	while ((sc = sizeCtl) >= 0) {
1886	+	Node<K,V>[] tab = table; int n;
1887	+	if (tab == null || (n = tab.length) == 0) {
1888	+	n = (sc > c) ? sc : c;
1889	+	if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
1890	+	try {
1891	+	if (table == tab) {
1892	+	table = (Node<K,V>[])new Node[n];
1893	+	sc = n - (n >>> 2);
1894	+	}
1895	+	} finally {
1896	+	sizeCtl = sc;
1897		}
1898		}
597	–	} finally {
598	–	unlock();
1899		}
1900	<	return oldValue;
1900	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1901	>	break;
1902	>	else if (tab == table &&
1903	>	U.compareAndSwapInt(this, SIZECTL, sc, -2))
1904	>	transfer(tab, null);
1905		}
1906	+	}
1907
1908	<	final void clear() {
1909	<	lock();
1908	>	/**
1909	>	* Moves and/or copies the nodes in each bin to new table. See
1910	>	* above for explanation.
1911	>	*/
1912	>	private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) {
1913	>	int n = tab.length, stride;
1914	>	if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
1915	>	stride = MIN_TRANSFER_STRIDE; // subdivide range
1916	>	if (nextTab == null) {            // initiating
1917		try {
1918	<	HashEntry<K,V>[] tab = table;
1919	<	for (int i = 0; i < tab.length ; i++)
1920	<	setEntryAt(tab, i, null);
1921	<	++modCount;
1922	<	count = 0;
1923	<	} finally {
1924	<	unlock();
1918	>	nextTab = (Node<K,V>[])new Node[n << 1];
1919	>	} catch (Throwable ex) {      // try to cope with OOME
1920	>	sizeCtl = Integer.MAX_VALUE;
1921	>	return;
1922	>	}
1923	>	nextTable = nextTab;
1924	>	transferOrigin = n;
1925	>	transferIndex = n;
1926	>	Node<K,V> rev = new Node<K,V>(MOVED, tab, null, null);
1927	>	for (int k = n; k > 0;) {    // progressively reveal ready slots
1928	>	int nextk = (k > stride) ? k - stride : 0;
1929	>	for (int m = nextk; m < k; ++m)
1930	>	nextTab[m] = rev;
1931	>	for (int m = n + nextk; m < n + k; ++m)
1932	>	nextTab[m] = rev;
1933	>	U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
1934		}
1935		}
1936	+	int nextn = nextTab.length;
1937	+	Node<K,V> fwd = new Node<K,V>(MOVED, nextTab, null, null);
1938	+	boolean advance = true;
1939	+	for (int i = 0, bound = 0;;) {
1940	+	int nextIndex, nextBound; Node<K,V> f; Object fk;
1941	+	while (advance) {
1942	+	if (--i >= bound)
1943	+	advance = false;
1944	+	else if ((nextIndex = transferIndex) <= transferOrigin) {
1945	+	i = -1;
1946	+	advance = false;
1947	+	}
1948	+	else if (U.compareAndSwapInt
1949	+	(this, TRANSFERINDEX, nextIndex,
1950	+	nextBound = (nextIndex > stride ?
1951	+	nextIndex - stride : 0))) {
1952	+	bound = nextBound;
1953	+	i = nextIndex - 1;
1954	+	advance = false;
1955	+	}
1956	+	}
1957	+	if (i < 0 || i >= n || i + n >= nextn) {
1958	+	for (int sc;;) {
1959	+	if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
1960	+	if (sc == -1) {
1961	+	nextTable = null;
1962	+	table = nextTab;
1963	+	sizeCtl = (n << 1) - (n >>> 1);
1964	+	}
1965	+	return;
1966	+	}
1967	+	}
1968	+	}
1969	+	else if ((f = tabAt(tab, i)) == null) {
1970	+	if (casTabAt(tab, i, null, fwd)) {
1971	+	setTabAt(nextTab, i, null);
1972	+	setTabAt(nextTab, i + n, null);
1973	+	advance = true;
1974	+	}
1975	+	}
1976	+	else if (f.hash >= 0) {
1977	+	synchronized (f) {
1978	+	if (tabAt(tab, i) == f) {
1979	+	int runBit = f.hash & n;
1980	+	Node<K,V> lastRun = f, lo = null, hi = null;
1981	+	for (Node<K,V> p = f.next; p != null; p = p.next) {
1982	+	int b = p.hash & n;
1983	+	if (b != runBit) {
1984	+	runBit = b;
1985	+	lastRun = p;
1986	+	}
1987	+	}
1988	+	if (runBit == 0)
1989	+	lo = lastRun;
1990	+	else
1991	+	hi = lastRun;
1992	+	for (Node<K,V> p = f; p != lastRun; p = p.next) {
1993	+	int ph = p.hash; Object pk = p.key; V pv = p.val;
1994	+	if ((ph & n) == 0)
1995	+	lo = new Node<K,V>(ph, pk, pv, lo);
1996	+	else
1997	+	hi = new Node<K,V>(ph, pk, pv, hi);
1998	+	}
1999	+	setTabAt(nextTab, i, lo);
2000	+	setTabAt(nextTab, i + n, hi);
2001	+	setTabAt(tab, i, fwd);
2002	+	advance = true;
2003	+	}
2004	+	}
2005	+	}
2006	+	else if ((fk = f.key) instanceof TreeBin) {
2007	+	TreeBin<K,V> t = (TreeBin<K,V>)fk;
2008	+	long stamp = t.writeLock();
2009	+	try {
2010	+	if (tabAt(tab, i) == f) {
2011	+	TreeNode<K,V> root;
2012	+	Node<K,V> ln = null, hn = null;
2013	+	if ((root = t.root) != null) {
2014	+	Node<K,V> e, p; TreeNode<K,V> lr, rr; int lh;
2015	+	TreeBin<K,V> lt = null, ht = null;
2016	+	for (lr = root; lr.left != null; lr = lr.left);
2017	+	for (rr = root; rr.right != null; rr = rr.right);
2018	+	if ((lh = lr.hash) == rr.hash) { // move entire tree
2019	+	if ((lh & n) == 0)
2020	+	lt = t;
2021	+	else
2022	+	ht = t;
2023	+	}
2024	+	else {
2025	+	lt = new TreeBin<K,V>();
2026	+	ht = new TreeBin<K,V>();
2027	+	int lc = 0, hc = 0;
2028	+	for (e = t.first; e != null; e = e.next) {
2029	+	int h = e.hash;
2030	+	Object k = e.key; V v = e.val;
2031	+	if ((h & n) == 0) {
2032	+	++lc;
2033	+	lt.putTreeNode(h, k, v);
2034	+	}
2035	+	else {
2036	+	++hc;
2037	+	ht.putTreeNode(h, k, v);
2038	+	}
2039	+	}
2040	+	if (lc < TREE_THRESHOLD) { // throw away
2041	+	for (p = lt.first; p != null; p = p.next)
2042	+	ln = new Node<K,V>(p.hash, p.key,
2043	+	p.val, ln);
2044	+	lt = null;
2045	+	}
2046	+	if (hc < TREE_THRESHOLD) {
2047	+	for (p = ht.first; p != null; p = p.next)
2048	+	hn = new Node<K,V>(p.hash, p.key,
2049	+	p.val, hn);
2050	+	ht = null;
2051	+	}
2052	+	}
2053	+	if (ln == null && lt != null)
2054	+	ln = new Node<K,V>(MOVED, lt, null, null);
2055	+	if (hn == null && ht != null)
2056	+	hn = new Node<K,V>(MOVED, ht, null, null);
2057	+	}
2058	+	setTabAt(nextTab, i, ln);
2059	+	setTabAt(nextTab, i + n, hn);
2060	+	setTabAt(tab, i, fwd);
2061	+	advance = true;
2062	+	}
2063	+	} finally {
2064	+	t.unlockWrite(stamp);
2065	+	}
2066	+	}
2067	+	else
2068	+	advance = true; // already processed
2069	+	}
2070		}
2071
2072	<	// Accessing segments
2073	<
2074	<	/**
2075	<	* Gets the jth element of given segment array (if nonnull) with
2076	<	* volatile element access semantics via Unsafe. (The null check
2077	<	* can trigger harmlessly only during deserialization.) Note:
2078	<	* because each element of segments array is set only once (using
2079	<	* fully ordered writes), some performance-sensitive methods rely
2080	<	* on this method only as a recheck upon null reads.
2081	<	*/
2082	<	@SuppressWarnings("unchecked")
2083	<	static final <K,V> Segment<K,V> segmentAt(Segment<K,V>[] ss, int j) {
629	<	long u = (j << SSHIFT) + SBASE;
630	<	return ss == null ? null :
631	<	(Segment<K,V>) UNSAFE.getObjectVolatile(ss, u);
2072	>	/* ---------------- Counter support -------------- */
2073	>
2074	>	final long sumCount() {
2075	>	Cell[] as = counterCells; Cell a;
2076	>	long sum = baseCount;
2077	>	if (as != null) {
2078	>	for (int i = 0; i < as.length; ++i) {
2079	>	if ((a = as[i]) != null)
2080	>	sum += a.value;
2081	>	}
2082	>	}
2083	>	return sum;
2084		}
2085
2086	<	/**
2087	<	* Returns the segment for the given index, creating it and
2088	<	* recording in segment table (via CAS) if not already present.
2089	<	*
2090	<	* @param k the index
2091	<	* @return the segment
2092	<	*/
2093	<	@SuppressWarnings("unchecked")
2094	<	private Segment<K,V> ensureSegment(int k) {
2095	<	final Segment<K,V>[] ss = this.segments;
2096	<	long u = (k << SSHIFT) + SBASE; // raw offset
2097	<	Segment<K,V> seg;
2098	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u)) == null) {
2099	<	Segment<K,V> proto = ss[0]; // use segment 0 as prototype
2100	<	int cap = proto.table.length;
2101	<	float lf = proto.loadFactor;
2102	<	int threshold = (int)(cap * lf);
2103	<	HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry[cap];
2104	<	if ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
2105	<	== null) { // recheck
2106	<	Segment<K,V> s = new Segment<K,V>(lf, threshold, tab);
2107	<	while ((seg = (Segment<K,V>)UNSAFE.getObjectVolatile(ss, u))
2108	<	== null) {
2109	<	if (UNSAFE.compareAndSwapObject(ss, u, null, seg = s))
2110	<	break;
2086	>	// See LongAdder version for explanation
2087	>	private final void fullAddCount(long x, boolean wasUncontended) {
2088	>	int h;
2089	>	if ((h = ThreadLocalRandom.getProbe()) == 0) {
2090	>	ThreadLocalRandom.localInit();      // force initialization
2091	>	h = ThreadLocalRandom.getProbe();
2092	>	wasUncontended = true;
2093	>	}
2094	>	boolean collide = false;                // True if last slot nonempty
2095	>	for (;;) {
2096	>	Cell[] as; Cell a; int n; long v;
2097	>	if ((as = counterCells) != null && (n = as.length) > 0) {
2098	>	if ((a = as[(n - 1) & h]) == null) {
2099	>	if (cellsBusy == 0) {            // Try to attach new Cell
2100	>	Cell r = new Cell(x); // Optimistic create
2101	>	if (cellsBusy == 0 &&
2102	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2103	>	boolean created = false;
2104	>	try {               // Recheck under lock
2105	>	Cell[] rs; int m, j;
2106	>	if ((rs = counterCells) != null &&
2107	>	(m = rs.length) > 0 &&
2108	>	rs[j = (m - 1) & h] == null) {
2109	>	rs[j] = r;
2110	>	created = true;
2111	>	}
2112	>	} finally {
2113	>	cellsBusy = 0;
2114	>	}
2115	>	if (created)
2116	>	break;
2117	>	continue;           // Slot is now non-empty
2118	>	}
2119	>	}
2120	>	collide = false;
2121	>	}
2122	>	else if (!wasUncontended)       // CAS already known to fail
2123	>	wasUncontended = true;      // Continue after rehash
2124	>	else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
2125	>	break;
2126	>	else if (counterCells != as || n >= NCPU)
2127	>	collide = false;            // At max size or stale
2128	>	else if (!collide)
2129	>	collide = true;
2130	>	else if (cellsBusy == 0 &&
2131	>	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2132	>	try {
2133	>	if (counterCells == as) {// Expand table unless stale
2134	>	Cell[] rs = new Cell[n << 1];
2135	>	for (int i = 0; i < n; ++i)
2136	>	rs[i] = as[i];
2137	>	counterCells = rs;
2138	>	}
2139	>	} finally {
2140	>	cellsBusy = 0;
2141	>	}
2142	>	collide = false;
2143	>	continue;                   // Retry with expanded table
2144		}
2145	+	h = ThreadLocalRandom.advanceProbe(h);
2146	+	}
2147	+	else if (cellsBusy == 0 && counterCells == as &&
2148	+	U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) {
2149	+	boolean init = false;
2150	+	try {                           // Initialize table
2151	+	if (counterCells == as) {
2152	+	Cell[] rs = new Cell[2];
2153	+	rs[h & 1] = new Cell(x);
2154	+	counterCells = rs;
2155	+	init = true;
2156	+	}
2157	+	} finally {
2158	+	cellsBusy = 0;
2159	+	}
2160	+	if (init)
2161	+	break;
2162		}
2163	+	else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
2164	+	break;                          // Fall back on using base
2165		}
662	–	return seg;
2166		}
2167
2168	<	// Hash-based segment and entry accesses
2168	>	/* ----------------Table Traversal -------------- */
2169
2170		/**
2171	<	* Gets the segment for the given hash code.
2172	<	*/
2173	<	@SuppressWarnings("unchecked")
2174	<	private Segment<K,V> segmentForHash(int h) {
2175	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
2176	<	return (Segment<K,V>) UNSAFE.getObjectVolatile(segments, u);
2171	>	* Encapsulates traversal for methods such as containsValue; also
2172	>	* serves as a base class for other iterators and spliterators.
2173	>	*
2174	>	* Method advance visits once each still-valid node that was
2175	>	* reachable upon iterator construction. It might miss some that
2176	>	* were added to a bin after the bin was visited, which is OK wrt
2177	>	* consistency guarantees. Maintaining this property in the face
2178	>	* of possible ongoing resizes requires a fair amount of
2179	>	* bookkeeping state that is difficult to optimize away amidst
2180	>	* volatile accesses.  Even so, traversal maintains reasonable
2181	>	* throughput.
2182	>	*
2183	>	* Normally, iteration proceeds bin-by-bin traversing lists.
2184	>	* However, if the table has been resized, then all future steps
2185	>	* must traverse both the bin at the current index as well as at
2186	>	* (index + baseSize); and so on for further resizings. To
2187	>	* paranoically cope with potential sharing by users of iterators
2188	>	* across threads, iteration terminates if a bounds checks fails
2189	>	* for a table read.
2190	>	*/
2191	>	static class Traverser<K,V> {
2192	>	Node<K,V>[] tab;        // current table; updated if resized
2193	>	Node<K,V> next;         // the next entry to use
2194	>	int index;              // index of bin to use next
2195	>	int baseIndex;          // current index of initial table
2196	>	int baseLimit;          // index bound for initial table
2197	>	final int baseSize;     // initial table size
2198	>
2199	>	Traverser(Node<K,V>[] tab, int size, int index, int limit) {
2200	>	this.tab = tab;
2201	>	this.baseSize = size;
2202	>	this.baseIndex = this.index = index;
2203	>	this.baseLimit = limit;
2204	>	this.next = null;
2205	>	}
2206	>
2207	>	/**
2208	>	* Advances if possible, returning next valid node, or null if none.
2209	>	*/
2210	>	final Node<K,V> advance() {
2211	>	Node<K,V> e;
2212	>	if ((e = next) != null)
2213	>	e = e.next;
2214	>	for (;;) {
2215	>	Node<K,V>[] t; int i, n; Object ek;  // must use locals in checks
2216	>	if (e != null)
2217	>	return next = e;
2218	>	if (baseIndex >= baseLimit || (t = tab) == null ||
2219	>	(n = t.length) <= (i = index) || i < 0)
2220	>	return next = null;
2221	>	if ((e = tabAt(t, index)) != null && e.hash < 0) {
2222	>	if ((ek = e.key) instanceof TreeBin)
2223	>	e = ((TreeBin<K,V>)ek).first;
2224	>	else {
2225	>	tab = (Node<K,V>[])ek;
2226	>	e = null;
2227	>	continue;
2228	>	}
2229	>	}
2230	>	if ((index += baseSize) >= n)
2231	>	index = ++baseIndex;    // visit upper slots if present
2232	>	}
2233	>	}
2234		}
2235
2236		/**
2237	<	* Gets the table entry for the given segment and hash code.
2237	>	* Base of key, value, and entry Iterators. Adds fields to
2238	>	* Traverser to support iterator.remove
2239		*/
2240	<	@SuppressWarnings("unchecked")
2241	<	static final <K,V> HashEntry<K,V> entryForHash(Segment<K,V> seg, int h) {
2242	<	HashEntry<K,V>[] tab;
2243	<	return (seg == null || (tab = seg.table) == null) ? null :
2244	<	(HashEntry<K,V>) UNSAFE.getObjectVolatile
2245	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
2240	>	static class BaseIterator<K,V> extends Traverser<K,V> {
2241	>	final ConcurrentHashMap<K,V> map;
2242	>	Node<K,V> lastReturned;
2243	>	BaseIterator(Node<K,V>[] tab, int size, int index, int limit,
2244	>	ConcurrentHashMap<K,V> map) {
2245	>	super(tab, size, index, limit);
2246	>	this.map = map;
2247	>	advance();
2248	>	}
2249	>
2250	>	public final boolean hasNext() { return next != null; }
2251	>	public final boolean hasMoreElements() { return next != null; }
2252	>
2253	>	public final void remove() {
2254	>	Node<K,V> p;
2255	>	if ((p = lastReturned) == null)
2256	>	throw new IllegalStateException();
2257	>	lastReturned = null;
2258	>	map.internalReplace((K)p.key, null, null);
2259	>	}
2260	>	}
2261	>
2262	>	static final class KeyIterator<K,V> extends BaseIterator<K,V>
2263	>	implements Iterator<K>, Enumeration<K> {
2264	>	KeyIterator(Node<K,V>[] tab, int index, int size, int limit,
2265	>	ConcurrentHashMap<K,V> map) {
2266	>	super(tab, index, size, limit, map);
2267	>	}
2268	>
2269	>	public final K next() {
2270	>	Node<K,V> p;
2271	>	if ((p = next) == null)
2272	>	throw new NoSuchElementException();
2273	>	K k = (K)p.key;
2274	>	lastReturned = p;
2275	>	advance();
2276	>	return k;
2277	>	}
2278	>
2279	>	public final K nextElement() { return next(); }
2280	>	}
2281	>
2282	>	static final class ValueIterator<K,V> extends BaseIterator<K,V>
2283	>	implements Iterator<V>, Enumeration<V> {
2284	>	ValueIterator(Node<K,V>[] tab, int index, int size, int limit,
2285	>	ConcurrentHashMap<K,V> map) {
2286	>	super(tab, index, size, limit, map);
2287	>	}
2288	>
2289	>	public final V next() {
2290	>	Node<K,V> p;
2291	>	if ((p = next) == null)
2292	>	throw new NoSuchElementException();
2293	>	V v = p.val;
2294	>	lastReturned = p;
2295	>	advance();
2296	>	return v;
2297	>	}
2298	>
2299	>	public final V nextElement() { return next(); }
2300		}
2301
2302	+	static final class EntryIterator<K,V> extends BaseIterator<K,V>
2303	+	implements Iterator<Map.Entry<K,V>> {
2304	+	EntryIterator(Node<K,V>[] tab, int index, int size, int limit,
2305	+	ConcurrentHashMap<K,V> map) {
2306	+	super(tab, index, size, limit, map);
2307	+	}
2308	+
2309	+	public final Map.Entry<K,V> next() {
2310	+	Node<K,V> p;
2311	+	if ((p = next) == null)
2312	+	throw new NoSuchElementException();
2313	+	K k = (K)p.key;
2314	+	V v = p.val;
2315	+	lastReturned = p;
2316	+	advance();
2317	+	return new MapEntry<K,V>(k, v, map);
2318	+	}
2319	+	}
2320	+
2321	+	static final class KeySpliterator<K,V> extends Traverser<K,V>
2322	+	implements Spliterator<K> {
2323	+	long est;               // size estimate
2324	+	KeySpliterator(Node<K,V>[] tab, int size, int index, int limit,
2325	+	long est) {
2326	+	super(tab, size, index, limit);
2327	+	this.est = est;
2328	+	}
2329	+
2330	+	public Spliterator<K> trySplit() {
2331	+	int i, f, h;
2332	+	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
2333	+	new KeySpliterator<K,V>(tab, baseSize, baseLimit = h,
2334	+	f, est >>>= 1);
2335	+	}
2336	+
2337	+	public void forEachRemaining(Consumer<? super K> action) {
2338	+	if (action == null) throw new NullPointerException();
2339	+	for (Node<K,V> p; (p = advance()) != null;)
2340	+	action.accept((K)p.key);
2341	+	}
2342	+
2343	+	public boolean tryAdvance(Consumer<? super K> action) {
2344	+	if (action == null) throw new NullPointerException();
2345	+	Node<K,V> p;
2346	+	if ((p = advance()) == null)
2347	+	return false;
2348	+	action.accept((K)p.key);
2349	+	return true;
2350	+	}
2351	+
2352	+	public long estimateSize() { return est; }
2353	+
2354	+	public int characteristics() {
2355	+	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
2356	+	Spliterator.NONNULL;
2357	+	}
2358	+	}
2359	+
2360	+	static final class ValueSpliterator<K,V> extends Traverser<K,V>
2361	+	implements Spliterator<V> {
2362	+	long est;               // size estimate
2363	+	ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit,
2364	+	long est) {
2365	+	super(tab, size, index, limit);
2366	+	this.est = est;
2367	+	}
2368	+
2369	+	public Spliterator<V> trySplit() {
2370	+	int i, f, h;
2371	+	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
2372	+	new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h,
2373	+	f, est >>>= 1);
2374	+	}
2375	+
2376	+	public void forEachRemaining(Consumer<? super V> action) {
2377	+	if (action == null) throw new NullPointerException();
2378	+	for (Node<K,V> p; (p = advance()) != null;)
2379	+	action.accept(p.val);
2380	+	}
2381	+
2382	+	public boolean tryAdvance(Consumer<? super V> action) {
2383	+	if (action == null) throw new NullPointerException();
2384	+	Node<K,V> p;
2385	+	if ((p = advance()) == null)
2386	+	return false;
2387	+	action.accept(p.val);
2388	+	return true;
2389	+	}
2390	+
2391	+	public long estimateSize() { return est; }
2392	+
2393	+	public int characteristics() {
2394	+	return Spliterator.CONCURRENT | Spliterator.NONNULL;
2395	+	}
2396	+	}
2397	+
2398	+	static final class EntrySpliterator<K,V> extends Traverser<K,V>
2399	+	implements Spliterator<Map.Entry<K,V>> {
2400	+	final ConcurrentHashMap<K,V> map; // To export MapEntry
2401	+	long est;               // size estimate
2402	+	EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit,
2403	+	long est, ConcurrentHashMap<K,V> map) {
2404	+	super(tab, size, index, limit);
2405	+	this.map = map;
2406	+	this.est = est;
2407	+	}
2408	+
2409	+	public Spliterator<Map.Entry<K,V>> trySplit() {
2410	+	int i, f, h;
2411	+	return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null :
2412	+	new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h,
2413	+	f, est >>>= 1, map);
2414	+	}
2415	+
2416	+	public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
2417	+	if (action == null) throw new NullPointerException();
2418	+	for (Node<K,V> p; (p = advance()) != null; )
2419	+	action.accept(new MapEntry<K,V>((K)p.key, p.val, map));
2420	+	}
2421	+
2422	+	public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
2423	+	if (action == null) throw new NullPointerException();
2424	+	Node<K,V> p;
2425	+	if ((p = advance()) == null)
2426	+	return false;
2427	+	action.accept(new MapEntry<K,V>((K)p.key, p.val, map));
2428	+	return true;
2429	+	}
2430	+
2431	+	public long estimateSize() { return est; }
2432	+
2433	+	public int characteristics() {
2434	+	return Spliterator.DISTINCT | Spliterator.CONCURRENT |
2435	+	Spliterator.NONNULL;
2436	+	}
2437	+	}
2438	+
2439	+
2440		/* ---------------- Public operations -------------- */
2441
2442		/**
2443	<	* Creates a new, empty map with the specified initial
691	<	* capacity, load factor and concurrency level.
692	<	*
693	<	* @param initialCapacity the initial capacity. The implementation
694	<	* performs internal sizing to accommodate this many elements.
695	<	* @param loadFactor  the load factor threshold, used to control resizing.
696	<	* Resizing may be performed when the average number of elements per
697	<	* bin exceeds this threshold.
698	<	* @param concurrencyLevel the estimated number of concurrently
699	<	* updating threads. The implementation performs internal sizing
700	<	* to try to accommodate this many threads.
701	<	* @throws IllegalArgumentException if the initial capacity is
702	<	* negative or the load factor or concurrencyLevel are
703	<	* nonpositive.
2443	>	* Creates a new, empty map with the default initial table size (16).
2444		*/
2445	<	@SuppressWarnings("unchecked")
706	<	public ConcurrentHashMap(int initialCapacity,
707	<	float loadFactor, int concurrencyLevel) {
708	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
709	<	throw new IllegalArgumentException();
710	<	if (concurrencyLevel > MAX_SEGMENTS)
711	<	concurrencyLevel = MAX_SEGMENTS;
712	<	// Find power-of-two sizes best matching arguments
713	<	int sshift = 0;
714	<	int ssize = 1;
715	<	while (ssize < concurrencyLevel) {
716	<	++sshift;
717	<	ssize <<= 1;
718	<	}
719	<	this.segmentShift = 32 - sshift;
720	<	this.segmentMask = ssize - 1;
721	<	if (initialCapacity > MAXIMUM_CAPACITY)
722	<	initialCapacity = MAXIMUM_CAPACITY;
723	<	int c = initialCapacity / ssize;
724	<	if (c * ssize < initialCapacity)
725	<	++c;
726	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
727	<	while (cap < c)
728	<	cap <<= 1;
729	<	// create segments and segments[0]
730	<	Segment<K,V> s0 =
731	<	new Segment<K,V>(loadFactor, (int)(cap * loadFactor),
732	<	(HashEntry<K,V>[])new HashEntry[cap]);
733	<	Segment<K,V>[] ss = (Segment<K,V>[])new Segment[ssize];
734	<	UNSAFE.putOrderedObject(ss, SBASE, s0); // ordered write of segments[0]
735	<	this.segments = ss;
2445	>	public ConcurrentHashMap() {
2446		}
2447
2448		/**
2449	<	* Creates a new, empty map with the specified initial capacity
2450	<	* and load factor and with the default concurrencyLevel (16).
2449	>	* Creates a new, empty map with an initial table size
2450	>	* accommodating the specified number of elements without the need
2451	>	* to dynamically resize.
2452		*
2453		* @param initialCapacity The implementation performs internal
2454		* sizing to accommodate this many elements.
2455	<	* @param loadFactor  the load factor threshold, used to control resizing.
2456	<	* Resizing may be performed when the average number of elements per
2457	<	* bin exceeds this threshold.
2455	>	* @throws IllegalArgumentException if the initial capacity of
2456	>	* elements is negative
2457	>	*/
2458	>	public ConcurrentHashMap(int initialCapacity) {
2459	>	if (initialCapacity < 0)
2460	>	throw new IllegalArgumentException();
2461	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2462	>	MAXIMUM_CAPACITY :
2463	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2464	>	this.sizeCtl = cap;
2465	>	}
2466	>
2467	>	/**
2468	>	* Creates a new map with the same mappings as the given map.
2469	>	*
2470	>	* @param m the map
2471	>	*/
2472	>	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2473	>	this.sizeCtl = DEFAULT_CAPACITY;
2474	>	internalPutAll(m);
2475	>	}
2476	>
2477	>	/**
2478	>	* Creates a new, empty map with an initial table size based on
2479	>	* the given number of elements ({@code initialCapacity}) and
2480	>	* initial table density ({@code loadFactor}).
2481	>	*
2482	>	* @param initialCapacity the initial capacity. The implementation
2483	>	* performs internal sizing to accommodate this many elements,
2484	>	* given the specified load factor.
2485	>	* @param loadFactor the load factor (table density) for
2486	>	* establishing the initial table size
2487		* @throws IllegalArgumentException if the initial capacity of
2488		* elements is negative or the load factor is nonpositive
2489		*
2490		* @since 1.6
2491		*/
2492		public ConcurrentHashMap(int initialCapacity, float loadFactor) {
2493	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2493	>	this(initialCapacity, loadFactor, 1);
2494		}
2495
2496		/**
2497	<	* Creates a new, empty map with the specified initial capacity,
2498	<	* and with default load factor (0.75) and concurrencyLevel (16).
2497	>	* Creates a new, empty map with an initial table size based on
2498	>	* the given number of elements ({@code initialCapacity}), table
2499	>	* density ({@code loadFactor}), and number of concurrently
2500	>	* updating threads ({@code concurrencyLevel}).
2501		*
2502		* @param initialCapacity the initial capacity. The implementation
2503	<	* performs internal sizing to accommodate this many elements.
2504	<	* @throws IllegalArgumentException if the initial capacity of
2505	<	* elements is negative.
2503	>	* performs internal sizing to accommodate this many elements,
2504	>	* given the specified load factor.
2505	>	* @param loadFactor the load factor (table density) for
2506	>	* establishing the initial table size
2507	>	* @param concurrencyLevel the estimated number of concurrently
2508	>	* updating threads. The implementation may use this value as
2509	>	* a sizing hint.
2510	>	* @throws IllegalArgumentException if the initial capacity is
2511	>	* negative or the load factor or concurrencyLevel are
2512	>	* nonpositive
2513		*/
2514	<	public ConcurrentHashMap(int initialCapacity) {
2515	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2514	>	public ConcurrentHashMap(int initialCapacity,
2515	>	float loadFactor, int concurrencyLevel) {
2516	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2517	>	throw new IllegalArgumentException();
2518	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2519	>	initialCapacity = concurrencyLevel;   // as estimated threads
2520	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2521	>	int cap = (size >= (long)MAXIMUM_CAPACITY) ?
2522	>	MAXIMUM_CAPACITY : tableSizeFor((int)size);
2523	>	this.sizeCtl = cap;
2524		}
2525
2526		/**
2527	<	* Creates a new, empty map with a default initial capacity (16),
2528	<	* load factor (0.75) and concurrencyLevel (16).
2527	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2528	>	* from the given type to {@code Boolean.TRUE}.
2529	>	*
2530	>	* @return the new set
2531		*/
2532	<	public ConcurrentHashMap() {
2533	<	this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2532	>	public static <K> KeySetView<K,Boolean> newKeySet() {
2533	>	return new KeySetView<K,Boolean>
2534	>	(new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE);
2535		}
2536
2537		/**
2538	<	* Creates a new map with the same mappings as the given map.
2539	<	* The map is created with a capacity of 1.5 times the number
780	<	* of mappings in the given map or 16 (whichever is greater),
781	<	* and a default load factor (0.75) and concurrencyLevel (16).
2538	>	* Creates a new {@link Set} backed by a ConcurrentHashMap
2539	>	* from the given type to {@code Boolean.TRUE}.
2540		*
2541	<	* @param m the map
2541	>	* @param initialCapacity The implementation performs internal
2542	>	* sizing to accommodate this many elements.
2543	>	* @throws IllegalArgumentException if the initial capacity of
2544	>	* elements is negative
2545	>	* @return the new set
2546		*/
2547	<	public ConcurrentHashMap(Map<? extends K, ? extends V> m) {
2548	<	this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
2549	<	DEFAULT_INITIAL_CAPACITY),
788	<	DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
789	<	putAll(m);
2547	>	public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) {
2548	>	return new KeySetView<K,Boolean>
2549	>	(new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE);
2550		}
2551
2552		/**
2553	<	* Returns <tt>true</tt> if this map contains no key-value mappings.
794	<	*
795	<	* @return <tt>true</tt> if this map contains no key-value mappings
2553	>	* {@inheritDoc}
2554		*/
2555		public boolean isEmpty() {
2556	<	/*
799	<	* Sum per-segment modCounts to avoid mis-reporting when
800	<	* elements are concurrently added and removed in one segment
801	<	* while checking another, in which case the table was never
802	<	* actually empty at any point. (The sum ensures accuracy up
803	<	* through at least 1<<31 per-segment modifications before
804	<	* recheck.)  Methods size() and containsValue() use similar
805	<	* constructions for stability checks.
806	<	*/
807	<	long sum = 0L;
808	<	final Segment<K,V>[] segments = this.segments;
809	<	for (int j = 0; j < segments.length; ++j) {
810	<	Segment<K,V> seg = segmentAt(segments, j);
811	<	if (seg != null) {
812	<	if (seg.count != 0)
813	<	return false;
814	<	sum += seg.modCount;
815	<	}
816	<	}
817	<	if (sum != 0L) { // recheck unless no modifications
818	<	for (int j = 0; j < segments.length; ++j) {
819	<	Segment<K,V> seg = segmentAt(segments, j);
820	<	if (seg != null) {
821	<	if (seg.count != 0)
822	<	return false;
823	<	sum -= seg.modCount;
824	<	}
825	<	}
826	<	if (sum != 0L)
827	<	return false;
828	<	}
829	<	return true;
2556	>	return sumCount() <= 0L; // ignore transient negative values
2557		}
2558
2559		/**
2560	<	* Returns the number of key-value mappings in this map.  If the
834	<	* map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
835	<	* <tt>Integer.MAX_VALUE</tt>.
836	<	*
837	<	* @return the number of key-value mappings in this map
2560	>	* {@inheritDoc}
2561		*/
2562		public int size() {
2563	<	// Try a few times to get accurate count. On failure due to
2564	<	// continuous async changes in table, resort to locking.
2565	<	final Segment<K,V>[] segments = this.segments;
2566	<	int size;
2567	<	boolean overflow; // true if size overflows 32 bits
2568	<	long sum;         // sum of modCounts
2569	<	long last = 0L;   // previous sum
2570	<	int retries = -1; // first iteration isn't retry
2571	<	try {
2572	<	for (;;) {
2573	<	if (retries++ == RETRIES_BEFORE_LOCK) {
2574	<	for (int j = 0; j < segments.length; ++j)
2575	<	ensureSegment(j).lock(); // force creation
2576	<	}
2577	<	sum = 0L;
2578	<	size = 0;
2579	<	overflow = false;
2580	<	for (int j = 0; j < segments.length; ++j) {
858	<	Segment<K,V> seg = segmentAt(segments, j);
859	<	if (seg != null) {
860	<	sum += seg.modCount;
861	<	int c = seg.count;
862	<	if (c < 0 || (size += c) < 0)
863	<	overflow = true;
864	<	}
865	<	}
866	<	if (sum == last)
867	<	break;
868	<	last = sum;
869	<	}
870	<	} finally {
871	<	if (retries > RETRIES_BEFORE_LOCK) {
872	<	for (int j = 0; j < segments.length; ++j)
873	<	segmentAt(segments, j).unlock();
874	<	}
875	<	}
876	<	return overflow ? Integer.MAX_VALUE : size;
2563	>	long n = sumCount();
2564	>	return ((n < 0L) ? 0 :
2565	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2566	>	(int)n);
2567	>	}
2568	>
2569	>	/**
2570	>	* Returns the number of mappings. This method should be used
2571	>	* instead of {@link #size} because a ConcurrentHashMap may
2572	>	* contain more mappings than can be represented as an int. The
2573	>	* value returned is an estimate; the actual count may differ if
2574	>	* there are concurrent insertions or removals.
2575	>	*
2576	>	* @return the number of mappings
2577	>	*/
2578	>	public long mappingCount() {
2579	>	long n = sumCount();
2580	>	return (n < 0L) ? 0L : n; // ignore transient negative values
2581		}
2582
2583		/**
#	Line 888 | Line 2592 | public class ConcurrentHashMap<K, V> ext
2592		* @throws NullPointerException if the specified key is null
2593		*/
2594		public V get(Object key) {
2595	<	Segment<K,V> s; // manually integrate access methods to reduce overhead
2596	<	HashEntry<K,V>[] tab;
2597	<	int h = hash(key.hashCode());
2598	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
2599	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
2600	<	(tab = s.table) != null) {
2601	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
2602	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
2603	<	e != null; e = e.next) {
2604	<	K k;
2605	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
2606	<	return e.value;
2607	<	}
2608	<	}
2609	<	return null;
2595	>	return internalGet(key);
2596	>	}
2597	>
2598	>	/**
2599	>	* Returns the value to which the specified key is mapped,
2600	>	* or the given defaultValue if this map contains no mapping for the key.
2601	>	*
2602	>	* @param key the key
2603	>	* @param defaultValue the value to return if this map contains
2604	>	* no mapping for the given key
2605	>	* @return the mapping for the key, if present; else the defaultValue
2606	>	* @throws NullPointerException if the specified key is null
2607	>	*/
2608	>	public V getOrDefault(Object key, V defaultValue) {
2609	>	V v;
2610	>	return (v = internalGet(key)) == null ? defaultValue : v;
2611		}
2612
2613		/**
2614		* Tests if the specified object is a key in this table.
2615		*
2616	<	* @param  key   possible key
2617	<	* @return <tt>true</tt> if and only if the specified object
2616	>	* @param  key possible key
2617	>	* @return {@code true} if and only if the specified object
2618		*         is a key in this table, as determined by the
2619	<	*         <tt>equals</tt> method; <tt>false</tt> otherwise.
2619	>	*         {@code equals} method; {@code false} otherwise
2620		* @throws NullPointerException if the specified key is null
2621		*/
917	–	@SuppressWarnings("unchecked")
2622		public boolean containsKey(Object key) {
2623	<	Segment<K,V> s; // same as get() except no need for volatile value read
920	<	HashEntry<K,V>[] tab;
921	<	int h = hash(key.hashCode());
922	<	long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE;
923	<	if ((s = (Segment<K,V>)UNSAFE.getObjectVolatile(segments, u)) != null &&
924	<	(tab = s.table) != null) {
925	<	for (HashEntry<K,V> e = (HashEntry<K,V>) UNSAFE.getObjectVolatile
926	<	(tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE);
927	<	e != null; e = e.next) {
928	<	K k;
929	<	if ((k = e.key) == key || (e.hash == h && key.equals(k)))
930	<	return true;
931	<	}
932	<	}
933	<	return false;
2623	>	return internalGet(key) != null;
2624		}
2625
2626		/**
2627	<	* Returns <tt>true</tt> if this map maps one or more keys to the
2628	<	* specified value. Note: This method requires a full internal
2629	<	* traversal of the hash table, and so is much slower than
940	<	* method <tt>containsKey</tt>.
2627	>	* Returns {@code true} if this map maps one or more keys to the
2628	>	* specified value. Note: This method may require a full traversal
2629	>	* of the map, and is much slower than method {@code containsKey}.
2630		*
2631		* @param value value whose presence in this map is to be tested
2632	<	* @return <tt>true</tt> if this map maps one or more keys to the
2632	>	* @return {@code true} if this map maps one or more keys to the
2633		*         specified value
2634		* @throws NullPointerException if the specified value is null
2635		*/
2636		public boolean containsValue(Object value) {
948	–	// Same idea as size()
2637		if (value == null)
2638		throw new NullPointerException();
2639	<	final Segment<K,V>[] segments = this.segments;
2640	<	boolean found = false;
2641	<	long last = 0L;   // previous sum
2642	<	int retries = -1;
2643	<	try {
2644	<	outer: for (;;) {
2645	<	if (retries++ == RETRIES_BEFORE_LOCK) {
958	<	for (int j = 0; j < segments.length; ++j)
959	<	ensureSegment(j).lock(); // force creation
960	<	}
961	<	long sum = 0L;
962	<	for (int j = 0; j < segments.length; ++j) {
963	<	HashEntry<K,V>[] tab;
964	<	Segment<K,V> seg = segmentAt(segments, j);
965	<	if (seg != null && (tab = seg.table) != null) {
966	<	for (int i = 0 ; i < tab.length; i++) {
967	<	HashEntry<K,V> e;
968	<	for (e = entryAt(tab, i); e != null; e = e.next) {
969	<	V v = e.value;
970	<	if (v != null && value.equals(v)) {
971	<	found = true;
972	<	break outer;
973	<	}
974	<	}
975	<	}
976	<	sum += seg.modCount;
977	<	}
978	<	}
979	<	if (retries > 0 && sum == last)
980	<	break;
981	<	last = sum;
982	<	}
983	<	} finally {
984	<	if (retries > RETRIES_BEFORE_LOCK) {
985	<	for (int j = 0; j < segments.length; ++j)
986	<	segmentAt(segments, j).unlock();
2639	>	Node<K,V>[] t;
2640	>	if ((t = table) != null) {
2641	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
2642	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
2643	>	V v;
2644	>	if ((v = p.val) == value || value.equals(v))
2645	>	return true;
2646		}
2647		}
2648	<	return found;
2648	>	return false;
2649		}
2650
2651		/**
2652		* Legacy method testing if some key maps into the specified value
2653		* in this table.  This method is identical in functionality to
2654	<	* {@link #containsValue}, and exists solely to ensure
2654	>	* {@link #containsValue(Object)}, and exists solely to ensure
2655		* full compatibility with class {@link java.util.Hashtable},
2656		* which supported this method prior to introduction of the
2657		* Java Collections framework.
2658		*
2659		* @param  value a value to search for
2660	<	* @return <tt>true</tt> if and only if some key maps to the
2661	<	*         <tt>value</tt> argument in this table as
2662	<	*         determined by the <tt>equals</tt> method;
2663	<	*         <tt>false</tt> otherwise
2660	>	* @return {@code true} if and only if some key maps to the
2661	>	*         {@code value} argument in this table as
2662	>	*         determined by the {@code equals} method;
2663	>	*         {@code false} otherwise
2664		* @throws NullPointerException if the specified value is null
2665		*/
2666	<	public boolean contains(Object value) {
2666	>	@Deprecated public boolean contains(Object value) {
2667		return containsValue(value);
2668		}
2669
#	Line 1012 | Line 2671 | public class ConcurrentHashMap<K, V> ext
2671		* Maps the specified key to the specified value in this table.
2672		* Neither the key nor the value can be null.
2673		*
2674	<	* <p> The value can be retrieved by calling the <tt>get</tt> method
2674	>	* <p>The value can be retrieved by calling the {@code get} method
2675		* with a key that is equal to the original key.
2676		*
2677		* @param key key with which the specified value is to be associated
2678		* @param value value to be associated with the specified key
2679	<	* @return the previous value associated with <tt>key</tt>, or
2680	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2679	>	* @return the previous value associated with {@code key}, or
2680	>	*         {@code null} if there was no mapping for {@code key}
2681		* @throws NullPointerException if the specified key or value is null
2682		*/
1024	–	@SuppressWarnings("unchecked")
2683		public V put(K key, V value) {
2684	<	Segment<K,V> s;
1027	<	if (value == null)
1028	<	throw new NullPointerException();
1029	<	int hash = hash(key.hashCode());
1030	<	int j = (hash >>> segmentShift) & segmentMask;
1031	<	if ((s = (Segment<K,V>)UNSAFE.getObject          // nonvolatile; recheck
1032	<	(segments, (j << SSHIFT) + SBASE)) == null) //  in ensureSegment
1033	<	s = ensureSegment(j);
1034	<	return s.put(key, hash, value, false);
2684	>	return internalPut(key, value, false);
2685		}
2686
2687		/**
2688		* {@inheritDoc}
2689		*
2690		* @return the previous value associated with the specified key,
2691	<	*         or <tt>null</tt> if there was no mapping for the key
2691	>	*         or {@code null} if there was no mapping for the key
2692		* @throws NullPointerException if the specified key or value is null
2693		*/
1044	–	@SuppressWarnings("unchecked")
2694		public V putIfAbsent(K key, V value) {
2695	<	Segment<K,V> s;
1047	<	if (value == null)
1048	<	throw new NullPointerException();
1049	<	int hash = hash(key.hashCode());
1050	<	int j = (hash >>> segmentShift) & segmentMask;
1051	<	if ((s = (Segment<K,V>)UNSAFE.getObject
1052	<	(segments, (j << SSHIFT) + SBASE)) == null)
1053	<	s = ensureSegment(j);
1054	<	return s.put(key, hash, value, true);
2695	>	return internalPut(key, value, true);
2696		}
2697
2698		/**
#	Line 1062 | Line 2703 | public class ConcurrentHashMap<K, V> ext
2703		* @param m mappings to be stored in this map
2704		*/
2705		public void putAll(Map<? extends K, ? extends V> m) {
2706	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
2707	<	put(e.getKey(), e.getValue());
2706	>	internalPutAll(m);
2707	>	}
2708	>
2709	>	/**
2710	>	* If the specified key is not already associated with a value (or
2711	>	* is mapped to {@code null}), attempts to compute its value using
2712	>	* the given mapping function and enters it into this map unless
2713	>	* {@code null}. The entire method invocation is performed
2714	>	* atomically, so the function is applied at most once per key.
2715	>	* Some attempted update operations on this map by other threads
2716	>	* may be blocked while computation is in progress, so the
2717	>	* computation should be short and simple, and must not attempt to
2718	>	* update any other mappings of this Map.
2719	>	*
2720	>	* @param key key with which the specified value is to be associated
2721	>	* @param mappingFunction the function to compute a value
2722	>	* @return the current (existing or computed) value associated with
2723	>	*         the specified key, or null if the computed value is null
2724	>	* @throws NullPointerException if the specified key or mappingFunction
2725	>	*         is null
2726	>	* @throws IllegalStateException if the computation detectably
2727	>	*         attempts a recursive update to this map that would
2728	>	*         otherwise never complete
2729	>	* @throws RuntimeException or Error if the mappingFunction does so,
2730	>	*         in which case the mapping is left unestablished
2731	>	*/
2732	>	public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) {
2733	>	return internalComputeIfAbsent(key, mappingFunction);
2734	>	}
2735	>
2736	>	/**
2737	>	* If the value for the specified key is present and non-null,
2738	>	* attempts to compute a new mapping given the key and its current
2739	>	* mapped value.  The entire method invocation is performed
2740	>	* atomically.  Some attempted update operations on this map by
2741	>	* other threads may be blocked while computation is in progress,
2742	>	* so the computation should be short and simple, and must not
2743	>	* attempt to update any other mappings of this Map.
2744	>	*
2745	>	* @param key key with which a value may be associated
2746	>	* @param remappingFunction the function to compute a value
2747	>	* @return the new value associated with the specified key, or null if none
2748	>	* @throws NullPointerException if the specified key or remappingFunction
2749	>	*         is null
2750	>	* @throws IllegalStateException if the computation detectably
2751	>	*         attempts a recursive update to this map that would
2752	>	*         otherwise never complete
2753	>	* @throws RuntimeException or Error if the remappingFunction does so,
2754	>	*         in which case the mapping is unchanged
2755	>	*/
2756	>	public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2757	>	return internalCompute(key, true, remappingFunction);
2758	>	}
2759	>
2760	>	/**
2761	>	* Attempts to compute a mapping for the specified key and its
2762	>	* current mapped value (or {@code null} if there is no current
2763	>	* mapping). The entire method invocation is performed atomically.
2764	>	* Some attempted update operations on this map by other threads
2765	>	* may be blocked while computation is in progress, so the
2766	>	* computation should be short and simple, and must not attempt to
2767	>	* update any other mappings of this Map.
2768	>	*
2769	>	* @param key key with which the specified value is to be associated
2770	>	* @param remappingFunction the function to compute a value
2771	>	* @return the new value associated with the specified key, or null if none
2772	>	* @throws NullPointerException if the specified key or remappingFunction
2773	>	*         is null
2774	>	* @throws IllegalStateException if the computation detectably
2775	>	*         attempts a recursive update to this map that would
2776	>	*         otherwise never complete
2777	>	* @throws RuntimeException or Error if the remappingFunction does so,
2778	>	*         in which case the mapping is unchanged
2779	>	*/
2780	>	public V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
2781	>	return internalCompute(key, false, remappingFunction);
2782	>	}
2783	>
2784	>	/**
2785	>	* If the specified key is not already associated with a
2786	>	* (non-null) value, associates it with the given value.
2787	>	* Otherwise, replaces the value with the results of the given
2788	>	* remapping function, or removes if {@code null}. The entire
2789	>	* method invocation is performed atomically.  Some attempted
2790	>	* update operations on this map by other threads may be blocked
2791	>	* while computation is in progress, so the computation should be
2792	>	* short and simple, and must not attempt to update any other
2793	>	* mappings of this Map.
2794	>	*
2795	>	* @param key key with which the specified value is to be associated
2796	>	* @param value the value to use if absent
2797	>	* @param remappingFunction the function to recompute a value if present
2798	>	* @return the new value associated with the specified key, or null if none
2799	>	* @throws NullPointerException if the specified key or the
2800	>	*         remappingFunction is null
2801	>	* @throws RuntimeException or Error if the remappingFunction does so,
2802	>	*         in which case the mapping is unchanged
2803	>	*/
2804	>	public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
2805	>	return internalMerge(key, value, remappingFunction);
2806		}
2807
2808		/**
#	Line 1071 | Line 2810 | public class ConcurrentHashMap<K, V> ext
2810		* This method does nothing if the key is not in the map.
2811		*
2812		* @param  key the key that needs to be removed
2813	<	* @return the previous value associated with <tt>key</tt>, or
2814	<	*         <tt>null</tt> if there was no mapping for <tt>key</tt>
2813	>	* @return the previous value associated with {@code key}, or
2814	>	*         {@code null} if there was no mapping for {@code key}
2815		* @throws NullPointerException if the specified key is null
2816		*/
2817		public V remove(Object key) {
2818	<	int hash = hash(key.hashCode());
1080	<	Segment<K,V> s = segmentForHash(hash);
1081	<	return s == null ? null : s.remove(key, hash, null);
2818	>	return internalReplace(key, null, null);
2819		}
2820
2821		/**
#	Line 1087 | Line 2824 | public class ConcurrentHashMap<K, V> ext
2824		* @throws NullPointerException if the specified key is null
2825		*/
2826		public boolean remove(Object key, Object value) {
2827	<	int hash = hash(key.hashCode());
2828	<	Segment<K,V> s;
2829	<	return value != null && (s = segmentForHash(hash)) != null &&
1093	<	s.remove(key, hash, value) != null;
2827	>	if (key == null)
2828	>	throw new NullPointerException();
2829	>	return value != null && internalReplace(key, null, value) != null;
2830		}
2831
2832		/**
#	Line 1099 | Line 2835 | public class ConcurrentHashMap<K, V> ext
2835		* @throws NullPointerException if any of the arguments are null
2836		*/
2837		public boolean replace(K key, V oldValue, V newValue) {
2838	<	int hash = hash(key.hashCode());
1103	<	if (oldValue == null || newValue == null)
2838	>	if (key == null || oldValue == null || newValue == null)
2839		throw new NullPointerException();
2840	<	Segment<K,V> s = segmentForHash(hash);
1106	<	return s != null && s.replace(key, hash, oldValue, newValue);
2840	>	return internalReplace(key, newValue, oldValue) != null;
2841		}
2842
2843		/**
2844		* {@inheritDoc}
2845		*
2846		* @return the previous value associated with the specified key,
2847	<	*         or <tt>null</tt> if there was no mapping for the key
2847	>	*         or {@code null} if there was no mapping for the key
2848		* @throws NullPointerException if the specified key or value is null
2849		*/
2850		public V replace(K key, V value) {
2851	<	int hash = hash(key.hashCode());
1118	<	if (value == null)
2851	>	if (key == null || value == null)
2852		throw new NullPointerException();
2853	<	Segment<K,V> s = segmentForHash(hash);
1121	<	return s == null ? null : s.replace(key, hash, value);
2853	>	return internalReplace(key, value, null);
2854		}
2855
2856		/**
2857		* Removes all of the mappings from this map.
2858		*/
2859		public void clear() {
2860	<	final Segment<K,V>[] segments = this.segments;
1129	<	for (int j = 0; j < segments.length; ++j) {
1130	<	Segment<K,V> s = segmentAt(segments, j);
1131	<	if (s != null)
1132	<	s.clear();
1133	<	}
2860	>	internalClear();
2861		}
2862
2863		/**
2864		* Returns a {@link Set} view of the keys contained in this map.
2865		* The set is backed by the map, so changes to the map are
2866	<	* reflected in the set, and vice-versa.  The set supports element
2866	>	* reflected in the set, and vice-versa. The set supports element
2867		* removal, which removes the corresponding mapping from this map,
2868	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2869	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2870	<	* operations.  It does not support the <tt>add</tt> or
2871	<	* <tt>addAll</tt> operations.
2868	>	* via the {@code Iterator.remove}, {@code Set.remove},
2869	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
2870	>	* operations.  It does not support the {@code add} or
2871	>	* {@code addAll} operations.
2872		*
2873	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2873	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2874		* that will never throw {@link ConcurrentModificationException},
2875		* and guarantees to traverse elements as they existed upon
2876		* construction of the iterator, and may (but is not guaranteed to)
2877		* reflect any modifications subsequent to construction.
2878	+	*
2879	+	* @return the set view
2880		*/
2881	<	public Set<K> keySet() {
2882	<	Set<K> ks = keySet;
2883	<	return (ks != null) ? ks : (keySet = new KeySet());
2881	>	public KeySetView<K,V> keySet() {
2882	>	KeySetView<K,V> ks = keySet;
2883	>	return (ks != null) ? ks : (keySet = new KeySetView<K,V>(this, null));
2884	>	}
2885	>
2886	>	/**
2887	>	* Returns a {@link Set} view of the keys in this map, using the
2888	>	* given common mapped value for any additions (i.e., {@link
2889	>	* Collection#add} and {@link Collection#addAll(Collection)}).
2890	>	* This is of course only appropriate if it is acceptable to use
2891	>	* the same value for all additions from this view.
2892	>	*
2893	>	* @param mappedValue the mapped value to use for any additions
2894	>	* @return the set view
2895	>	* @throws NullPointerException if the mappedValue is null
2896	>	*/
2897	>	public KeySetView<K,V> keySet(V mappedValue) {
2898	>	if (mappedValue == null)
2899	>	throw new NullPointerException();
2900	>	return new KeySetView<K,V>(this, mappedValue);
2901		}
2902
2903		/**
#	Line 1159 | Line 2905 | public class ConcurrentHashMap<K, V> ext
2905		* The collection is backed by the map, so changes to the map are
2906		* reflected in the collection, and vice-versa.  The collection
2907		* supports element removal, which removes the corresponding
2908	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
2909	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
2910	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
2911	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.
2908	>	* mapping from this map, via the {@code Iterator.remove},
2909	>	* {@code Collection.remove}, {@code removeAll},
2910	>	* {@code retainAll}, and {@code clear} operations.  It does not
2911	>	* support the {@code add} or {@code addAll} operations.
2912		*
2913	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2913	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2914		* that will never throw {@link ConcurrentModificationException},
2915		* and guarantees to traverse elements as they existed upon
2916		* construction of the iterator, and may (but is not guaranteed to)
2917		* reflect any modifications subsequent to construction.
2918	+	*
2919	+	* @return the collection view
2920		*/
2921		public Collection<V> values() {
2922	<	Collection<V> vs = values;
2923	<	return (vs != null) ? vs : (values = new Values());
2922	>	ValuesView<K,V> vs = values;
2923	>	return (vs != null) ? vs : (values = new ValuesView<K,V>(this));
2924		}
2925
2926		/**
#	Line 1180 | Line 2928 | public class ConcurrentHashMap<K, V> ext
2928		* The set is backed by the map, so changes to the map are
2929		* reflected in the set, and vice-versa.  The set supports element
2930		* removal, which removes the corresponding mapping from the map,
2931	<	* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
2932	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2933	<	* operations.  It does not support the <tt>add</tt> or
1186	<	* <tt>addAll</tt> operations.
2931	>	* via the {@code Iterator.remove}, {@code Set.remove},
2932	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
2933	>	* operations.
2934		*
2935	<	* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
2935	>	* <p>The view's {@code iterator} is a "weakly consistent" iterator
2936		* that will never throw {@link ConcurrentModificationException},
2937		* and guarantees to traverse elements as they existed upon
2938		* construction of the iterator, and may (but is not guaranteed to)
2939		* reflect any modifications subsequent to construction.
2940	+	*
2941	+	* @return the set view
2942		*/
2943		public Set<Map.Entry<K,V>> entrySet() {
2944	<	Set<Map.Entry<K,V>> es = entrySet;
2945	<	return (es != null) ? es : (entrySet = new EntrySet());
2944	>	EntrySetView<K,V> es = entrySet;
2945	>	return (es != null) ? es : (entrySet = new EntrySetView<K,V>(this));
2946		}
2947
2948		/**
#	Line 1203 | Line 2952 | public class ConcurrentHashMap<K, V> ext
2952		* @see #keySet()
2953		*/
2954		public Enumeration<K> keys() {
2955	<	return new KeyIterator();
2955	>	Node<K,V>[] t;
2956	>	int f = (t = table) == null ? 0 : t.length;
2957	>	return new KeyIterator<K,V>(t, f, 0, f, this);
2958		}
2959
2960		/**
#	Line 1213 | Line 2964 | public class ConcurrentHashMap<K, V> ext
2964		* @see #values()
2965		*/
2966		public Enumeration<V> elements() {
2967	<	return new ValueIterator();
2967	>	Node<K,V>[] t;
2968	>	int f = (t = table) == null ? 0 : t.length;
2969	>	return new ValueIterator<K,V>(t, f, 0, f, this);
2970		}
2971
2972	<	/* ---------------- Iterator Support -------------- */
2972	>	/**
2973	>	* Returns the hash code value for this {@link Map}, i.e.,
2974	>	* the sum of, for each key-value pair in the map,
2975	>	* {@code key.hashCode() ^ value.hashCode()}.
2976	>	*
2977	>	* @return the hash code value for this map
2978	>	*/
2979	>	public int hashCode() {
2980	>	int h = 0;
2981	>	Node<K,V>[] t;
2982	>	if ((t = table) != null) {
2983	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
2984	>	for (Node<K,V> p; (p = it.advance()) != null; )
2985	>	h += p.key.hashCode() ^ p.val.hashCode();
2986	>	}
2987	>	return h;
2988	>	}
2989
2990	<	abstract class HashIterator {
2991	<	int nextSegmentIndex;
2992	<	int nextTableIndex;
2993	<	HashEntry<K,V>[] currentTable;
2994	<	HashEntry<K, V> nextEntry;
2995	<	HashEntry<K, V> lastReturned;
2990	>	/**
2991	>	* Returns a string representation of this map.  The string
2992	>	* representation consists of a list of key-value mappings (in no
2993	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
2994	>	* mappings are separated by the characters {@code ", "} (comma
2995	>	* and space).  Each key-value mapping is rendered as the key
2996	>	* followed by an equals sign ("{@code =}") followed by the
2997	>	* associated value.
2998	>	*
2999	>	* @return a string representation of this map
3000	>	*/
3001	>	public String toString() {
3002	>	Node<K,V>[] t;
3003	>	int f = (t = table) == null ? 0 : t.length;
3004	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
3005	>	StringBuilder sb = new StringBuilder();
3006	>	sb.append('{');
3007	>	Node<K,V> p;
3008	>	if ((p = it.advance()) != null) {
3009	>	for (;;) {
3010	>	K k = (K)p.key;
3011	>	V v = p.val;
3012	>	sb.append(k == this ? "(this Map)" : k);
3013	>	sb.append('=');
3014	>	sb.append(v == this ? "(this Map)" : v);
3015	>	if ((p = it.advance()) == null)
3016	>	break;
3017	>	sb.append(',').append(' ');
3018	>	}
3019	>	}
3020	>	return sb.append('}').toString();
3021	>	}
3022
3023	<	HashIterator() {
3024	<	nextSegmentIndex = segments.length - 1;
3025	<	nextTableIndex = -1;
3026	<	advance();
3023	>	/**
3024	>	* Compares the specified object with this map for equality.
3025	>	* Returns {@code true} if the given object is a map with the same
3026	>	* mappings as this map.  This operation may return misleading
3027	>	* results if either map is concurrently modified during execution
3028	>	* of this method.
3029	>	*
3030	>	* @param o object to be compared for equality with this map
3031	>	* @return {@code true} if the specified object is equal to this map
3032	>	*/
3033	>	public boolean equals(Object o) {
3034	>	if (o != this) {
3035	>	if (!(o instanceof Map))
3036	>	return false;
3037	>	Map<?,?> m = (Map<?,?>) o;
3038	>	Node<K,V>[] t;
3039	>	int f = (t = table) == null ? 0 : t.length;
3040	>	Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f);
3041	>	for (Node<K,V> p; (p = it.advance()) != null; ) {
3042	>	V val = p.val;
3043	>	Object v = m.get(p.key);
3044	>	if (v == null || (v != val && !v.equals(val)))
3045	>	return false;
3046	>	}
3047	>	for (Map.Entry<?,?> e : m.entrySet()) {
3048	>	Object mk, mv, v;
3049	>	if ((mk = e.getKey()) == null ||
3050	>	(mv = e.getValue()) == null ||
3051	>	(v = internalGet(mk)) == null ||
3052	>	(mv != v && !mv.equals(v)))
3053	>	return false;
3054	>	}
3055	>	}
3056	>	return true;
3057	>	}
3058	>
3059	>	/* ---------------- Serialization Support -------------- */
3060	>
3061	>	/**
3062	>	* Stripped-down version of helper class used in previous version,
3063	>	* declared for the sake of serialization compatibility
3064	>	*/
3065	>	static class Segment<K,V> extends ReentrantLock implements Serializable {
3066	>	private static final long serialVersionUID = 2249069246763182397L;
3067	>	final float loadFactor;
3068	>	Segment(float lf) { this.loadFactor = lf; }
3069	>	}
3070	>
3071	>	/**
3072	>	* Saves the state of the {@code ConcurrentHashMap} instance to a
3073	>	* stream (i.e., serializes it).
3074	>	* @param s the stream
3075	>	* @serialData
3076	>	* the key (Object) and value (Object)
3077	>	* for each key-value mapping, followed by a null pair.
3078	>	* The key-value mappings are emitted in no particular order.
3079	>	*/
3080	>	private void writeObject(java.io.ObjectOutputStream s)
3081	>	throws java.io.IOException {
3082	>	// For serialization compatibility
3083	>	// Emulate segment calculation from previous version of this class
3084	>	int sshift = 0;
3085	>	int ssize = 1;
3086	>	while (ssize < DEFAULT_CONCURRENCY_LEVEL) {
3087	>	++sshift;
3088	>	ssize <<= 1;
3089		}
3090	+	int segmentShift = 32 - sshift;
3091	+	int segmentMask = ssize - 1;
3092	+	Segment<K,V>[] segments = (Segment<K,V>[])
3093	+	new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3094	+	for (int i = 0; i < segments.length; ++i)
3095	+	segments[i] = new Segment<K,V>(LOAD_FACTOR);
3096	+	s.putFields().put("segments", segments);
3097	+	s.putFields().put("segmentShift", segmentShift);
3098	+	s.putFields().put("segmentMask", segmentMask);
3099	+	s.writeFields();
3100	+
3101	+	Node<K,V>[] t;
3102	+	if ((t = table) != null) {
3103	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
3104	+	for (Node<K,V> p; (p = it.advance()) != null; ) {
3105	+	s.writeObject(p.key);
3106	+	s.writeObject(p.val);
3107	+	}
3108	+	}
3109	+	s.writeObject(null);
3110	+	s.writeObject(null);
3111	+	segments = null; // throw away
3112	+	}
3113	+
3114	+	/**
3115	+	* Reconstitutes the instance from a stream (that is, deserializes it).
3116	+	* @param s the stream
3117	+	*/
3118	+	private void readObject(java.io.ObjectInputStream s)
3119	+	throws java.io.IOException, ClassNotFoundException {
3120	+	s.defaultReadObject();
3121	+
3122	+	// Create all nodes, then place in table once size is known
3123	+	long size = 0L;
3124	+	Node<K,V> p = null;
3125	+	for (;;) {
3126	+	K k = (K) s.readObject();
3127	+	V v = (V) s.readObject();
3128	+	if (k != null && v != null) {
3129	+	int h = spread(k.hashCode());
3130	+	p = new Node<K,V>(h, k, v, p);
3131	+	++size;
3132	+	}
3133	+	else
3134	+	break;
3135	+	}
3136	+	if (p != null) {
3137	+	boolean init = false;
3138	+	int n;
3139	+	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3140	+	n = MAXIMUM_CAPACITY;
3141	+	else {
3142	+	int sz = (int)size;
3143	+	n = tableSizeFor(sz + (sz >>> 1) + 1);
3144	+	}
3145	+	int sc = sizeCtl;
3146	+	boolean collide = false;
3147	+	if (n > sc &&
3148	+	U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
3149	+	try {
3150	+	if (table == null) {
3151	+	init = true;
3152	+	Node<K,V>[] tab = (Node<K,V>[])new Node[n];
3153	+	int mask = n - 1;
3154	+	while (p != null) {
3155	+	int j = p.hash & mask;
3156	+	Node<K,V> next = p.next;
3157	+	Node<K,V> q = p.next = tabAt(tab, j);
3158	+	setTabAt(tab, j, p);
3159	+	if (!collide && q != null && q.hash == p.hash)
3160	+	collide = true;
3161	+	p = next;
3162	+	}
3163	+	table = tab;
3164	+	addCount(size, -1);
3165	+	sc = n - (n >>> 2);
3166	+	}
3167	+	} finally {
3168	+	sizeCtl = sc;
3169	+	}
3170	+	if (collide) { // rescan and convert to TreeBins
3171	+	Node<K,V>[] tab = table;
3172	+	for (int i = 0; i < tab.length; ++i) {
3173	+	int c = 0;
3174	+	for (Node<K,V> e = tabAt(tab, i); e != null; e = e.next) {
3175	+	if (++c > TREE_THRESHOLD &&
3176	+	(e.key instanceof Comparable)) {
3177	+	replaceWithTreeBin(tab, i, e.key);
3178	+	break;
3179	+	}
3180	+	}
3181	+	}
3182	+	}
3183	+	}
3184	+	if (!init) { // Can only happen if unsafely published.
3185	+	while (p != null) {
3186	+	internalPut((K)p.key, p.val, false);
3187	+	p = p.next;
3188	+	}
3189	+	}
3190	+	}
3191	+	}
3192	+
3193	+	// -------------------------------------------------------
3194	+
3195	+	// Overrides of other default Map methods
3196	+
3197	+	public void forEach(BiConsumer<? super K, ? super V> action) {
3198	+	if (action == null) throw new NullPointerException();
3199	+	Node<K,V>[] t;
3200	+	if ((t = table) != null) {
3201	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
3202	+	for (Node<K,V> p; (p = it.advance()) != null; ) {
3203	+	action.accept((K)p.key, p.val);
3204	+	}
3205	+	}
3206	+	}
3207	+
3208	+	public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
3209	+	if (function == null) throw new NullPointerException();
3210	+	Node<K,V>[] t;
3211	+	if ((t = table) != null) {
3212	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
3213	+	for (Node<K,V> p; (p = it.advance()) != null; ) {
3214	+	K k = (K)p.key;
3215	+	internalPut(k, function.apply(k, p.val), false);
3216	+	}
3217	+	}
3218	+	}
3219	+
3220	+	// -------------------------------------------------------
3221	+
3222	+	// Parallel bulk operations
3223	+
3224	+	/**
3225	+	* Computes initial batch value for bulk tasks. The returned value
3226	+	* is approximately exp2 of the number of times (minus one) to
3227	+	* split task by two before executing leaf action. This value is
3228	+	* faster to compute and more convenient to use as a guide to
3229	+	* splitting than is the depth, since it is used while dividing by
3230	+	* two anyway.
3231	+	*/
3232	+	final int batchFor(long b) {
3233	+	long n;
3234	+	if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b)
3235	+	return 0;
3236	+	int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4
3237	+	return (b <= 0L || (n /= b) >= sp) ? sp : (int)n;
3238	+	}
3239	+
3240	+	/**
3241	+	* Performs the given action for each (key, value).
3242	+	*
3243	+	* @param parallelismThreshold the (estimated) number of elements
3244	+	* needed for this operation to be executed in parallel
3245	+	* @param action the action
3246	+	*/
3247	+	public void forEach(long parallelismThreshold,
3248	+	BiConsumer<? super K,? super V> action) {
3249	+	if (action == null) throw new NullPointerException();
3250	+	new ForEachMappingTask<K,V>
3251	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3252	+	action).invoke();
3253	+	}
3254	+
3255	+	/**
3256	+	* Performs the given action for each non-null transformation
3257	+	* of each (key, value).
3258	+	*
3259	+	* @param parallelismThreshold the (estimated) number of elements
3260	+	* needed for this operation to be executed in parallel
3261	+	* @param transformer a function returning the transformation
3262	+	* for an element, or null if there is no transformation (in
3263	+	* which case the action is not applied)
3264	+	* @param action the action
3265	+	*/
3266	+	public <U> void forEach(long parallelismThreshold,
3267	+	BiFunction<? super K, ? super V, ? extends U> transformer,
3268	+	Consumer<? super U> action) {
3269	+	if (transformer == null || action == null)
3270	+	throw new NullPointerException();
3271	+	new ForEachTransformedMappingTask<K,V,U>
3272	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3273	+	transformer, action).invoke();
3274	+	}
3275	+
3276	+	/**
3277	+	* Returns a non-null result from applying the given search
3278	+	* function on each (key, value), or null if none.  Upon
3279	+	* success, further element processing is suppressed and the
3280	+	* results of any other parallel invocations of the search
3281	+	* function are ignored.
3282	+	*
3283	+	* @param parallelismThreshold the (estimated) number of elements
3284	+	* needed for this operation to be executed in parallel
3285	+	* @param searchFunction a function returning a non-null
3286	+	* result on success, else null
3287	+	* @return a non-null result from applying the given search
3288	+	* function on each (key, value), or null if none
3289	+	*/
3290	+	public <U> U search(long parallelismThreshold,
3291	+	BiFunction<? super K, ? super V, ? extends U> searchFunction) {
3292	+	if (searchFunction == null) throw new NullPointerException();
3293	+	return new SearchMappingsTask<K,V,U>
3294	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3295	+	searchFunction, new AtomicReference<U>()).invoke();
3296	+	}
3297	+
3298	+	/**
3299	+	* Returns the result of accumulating the given transformation
3300	+	* of all (key, value) pairs using the given reducer to
3301	+	* combine values, or null if none.
3302	+	*
3303	+	* @param parallelismThreshold the (estimated) number of elements
3304	+	* needed for this operation to be executed in parallel
3305	+	* @param transformer a function returning the transformation
3306	+	* for an element, or null if there is no transformation (in
3307	+	* which case it is not combined)
3308	+	* @param reducer a commutative associative combining function
3309	+	* @return the result of accumulating the given transformation
3310	+	* of all (key, value) pairs
3311	+	*/
3312	+	public <U> U reduce(long parallelismThreshold,
3313	+	BiFunction<? super K, ? super V, ? extends U> transformer,
3314	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
3315	+	if (transformer == null || reducer == null)
3316	+	throw new NullPointerException();
3317	+	return new MapReduceMappingsTask<K,V,U>
3318	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3319	+	null, transformer, reducer).invoke();
3320	+	}
3321	+
3322	+	/**
3323	+	* Returns the result of accumulating the given transformation
3324	+	* of all (key, value) pairs using the given reducer to
3325	+	* combine values, and the given basis as an identity value.
3326	+	*
3327	+	* @param parallelismThreshold the (estimated) number of elements
3328	+	* needed for this operation to be executed in parallel
3329	+	* @param transformer a function returning the transformation
3330	+	* for an element
3331	+	* @param basis the identity (initial default value) for the reduction
3332	+	* @param reducer a commutative associative combining function
3333	+	* @return the result of accumulating the given transformation
3334	+	* of all (key, value) pairs
3335	+	*/
3336	+	public double reduceToDoubleIn(long parallelismThreshold,
3337	+	ToDoubleBiFunction<? super K, ? super V> transformer,
3338	+	double basis,
3339	+	DoubleBinaryOperator reducer) {
3340	+	if (transformer == null || reducer == null)
3341	+	throw new NullPointerException();
3342	+	return new MapReduceMappingsToDoubleTask<K,V>
3343	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3344	+	null, transformer, basis, reducer).invoke();
3345	+	}
3346	+
3347	+	/**
3348	+	* Returns the result of accumulating the given transformation
3349	+	* of all (key, value) pairs using the given reducer to
3350	+	* combine values, and the given basis as an identity value.
3351	+	*
3352	+	* @param parallelismThreshold the (estimated) number of elements
3353	+	* needed for this operation to be executed in parallel
3354	+	* @param transformer a function returning the transformation
3355	+	* for an element
3356	+	* @param basis the identity (initial default value) for the reduction
3357	+	* @param reducer a commutative associative combining function
3358	+	* @return the result of accumulating the given transformation
3359	+	* of all (key, value) pairs
3360	+	*/
3361	+	public long reduceToLong(long parallelismThreshold,
3362	+	ToLongBiFunction<? super K, ? super V> transformer,
3363	+	long basis,
3364	+	LongBinaryOperator reducer) {
3365	+	if (transformer == null || reducer == null)
3366	+	throw new NullPointerException();
3367	+	return new MapReduceMappingsToLongTask<K,V>
3368	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3369	+	null, transformer, basis, reducer).invoke();
3370	+	}
3371	+
3372	+	/**
3373	+	* Returns the result of accumulating the given transformation
3374	+	* of all (key, value) pairs using the given reducer to
3375	+	* combine values, and the given basis as an identity value.
3376	+	*
3377	+	* @param parallelismThreshold the (estimated) number of elements
3378	+	* needed for this operation to be executed in parallel
3379	+	* @param transformer a function returning the transformation
3380	+	* for an element
3381	+	* @param basis the identity (initial default value) for the reduction
3382	+	* @param reducer a commutative associative combining function
3383	+	* @return the result of accumulating the given transformation
3384	+	* of all (key, value) pairs
3385	+	*/
3386	+	public int reduceToInt(long parallelismThreshold,
3387	+	ToIntBiFunction<? super K, ? super V> transformer,
3388	+	int basis,
3389	+	IntBinaryOperator reducer) {
3390	+	if (transformer == null || reducer == null)
3391	+	throw new NullPointerException();
3392	+	return new MapReduceMappingsToIntTask<K,V>
3393	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3394	+	null, transformer, basis, reducer).invoke();
3395	+	}
3396	+
3397	+	/**
3398	+	* Performs the given action for each key.
3399	+	*
3400	+	* @param parallelismThreshold the (estimated) number of elements
3401	+	* needed for this operation to be executed in parallel
3402	+	* @param action the action
3403	+	*/
3404	+	public void forEachKey(long parallelismThreshold,
3405	+	Consumer<? super K> action) {
3406	+	if (action == null) throw new NullPointerException();
3407	+	new ForEachKeyTask<K,V>
3408	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3409	+	action).invoke();
3410	+	}
3411	+
3412	+	/**
3413	+	* Performs the given action for each non-null transformation
3414	+	* of each key.
3415	+	*
3416	+	* @param parallelismThreshold the (estimated) number of elements
3417	+	* needed for this operation to be executed in parallel
3418	+	* @param transformer a function returning the transformation
3419	+	* for an element, or null if there is no transformation (in
3420	+	* which case the action is not applied)
3421	+	* @param action the action
3422	+	*/
3423	+	public <U> void forEachKey(long parallelismThreshold,
3424	+	Function<? super K, ? extends U> transformer,
3425	+	Consumer<? super U> action) {
3426	+	if (transformer == null || action == null)
3427	+	throw new NullPointerException();
3428	+	new ForEachTransformedKeyTask<K,V,U>
3429	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3430	+	transformer, action).invoke();
3431	+	}
3432	+
3433	+	/**
3434	+	* Returns a non-null result from applying the given search
3435	+	* function on each key, or null if none. Upon success,
3436	+	* further element processing is suppressed and the results of
3437	+	* any other parallel invocations of the search function are
3438	+	* ignored.
3439	+	*
3440	+	* @param parallelismThreshold the (estimated) number of elements
3441	+	* needed for this operation to be executed in parallel
3442	+	* @param searchFunction a function returning a non-null
3443	+	* result on success, else null
3444	+	* @return a non-null result from applying the given search
3445	+	* function on each key, or null if none
3446	+	*/
3447	+	public <U> U searchKeys(long parallelismThreshold,
3448	+	Function<? super K, ? extends U> searchFunction) {
3449	+	if (searchFunction == null) throw new NullPointerException();
3450	+	return new SearchKeysTask<K,V,U>
3451	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3452	+	searchFunction, new AtomicReference<U>()).invoke();
3453	+	}
3454	+
3455	+	/**
3456	+	* Returns the result of accumulating all keys using the given
3457	+	* reducer to combine values, or null if none.
3458	+	*
3459	+	* @param parallelismThreshold the (estimated) number of elements
3460	+	* needed for this operation to be executed in parallel
3461	+	* @param reducer a commutative associative combining function
3462	+	* @return the result of accumulating all keys using the given
3463	+	* reducer to combine values, or null if none
3464	+	*/
3465	+	public K reduceKeys(long parallelismThreshold,
3466	+	BiFunction<? super K, ? super K, ? extends K> reducer) {
3467	+	if (reducer == null) throw new NullPointerException();
3468	+	return new ReduceKeysTask<K,V>
3469	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3470	+	null, reducer).invoke();
3471	+	}
3472	+
3473	+	/**
3474	+	* Returns the result of accumulating the given transformation
3475	+	* of all keys using the given reducer to combine values, or
3476	+	* null if none.
3477	+	*
3478	+	* @param parallelismThreshold the (estimated) number of elements
3479	+	* needed for this operation to be executed in parallel
3480	+	* @param transformer a function returning the transformation
3481	+	* for an element, or null if there is no transformation (in
3482	+	* which case it is not combined)
3483	+	* @param reducer a commutative associative combining function
3484	+	* @return the result of accumulating the given transformation
3485	+	* of all keys
3486	+	*/
3487	+	public <U> U reduceKeys(long parallelismThreshold,
3488	+	Function<? super K, ? extends U> transformer,
3489	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
3490	+	if (transformer == null || reducer == null)
3491	+	throw new NullPointerException();
3492	+	return new MapReduceKeysTask<K,V,U>
3493	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3494	+	null, transformer, reducer).invoke();
3495	+	}
3496	+
3497	+	/**
3498	+	* Returns the result of accumulating the given transformation
3499	+	* of all keys using the given reducer to combine values, and
3500	+	* the given basis as an identity value.
3501	+	*
3502	+	* @param parallelismThreshold the (estimated) number of elements
3503	+	* needed for this operation to be executed in parallel
3504	+	* @param transformer a function returning the transformation
3505	+	* for an element
3506	+	* @param basis the identity (initial default value) for the reduction
3507	+	* @param reducer a commutative associative combining function
3508	+	* @return the result of accumulating the given transformation
3509	+	* of all keys
3510	+	*/
3511	+	public double reduceKeysToDouble(long parallelismThreshold,
3512	+	ToDoubleFunction<? super K> transformer,
3513	+	double basis,
3514	+	DoubleBinaryOperator reducer) {
3515	+	if (transformer == null || reducer == null)
3516	+	throw new NullPointerException();
3517	+	return new MapReduceKeysToDoubleTask<K,V>
3518	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3519	+	null, transformer, basis, reducer).invoke();
3520	+	}
3521	+
3522	+	/**
3523	+	* Returns the result of accumulating the given transformation
3524	+	* of all keys using the given reducer to combine values, and
3525	+	* the given basis as an identity value.
3526	+	*
3527	+	* @param parallelismThreshold the (estimated) number of elements
3528	+	* needed for this operation to be executed in parallel
3529	+	* @param transformer a function returning the transformation
3530	+	* for an element
3531	+	* @param basis the identity (initial default value) for the reduction
3532	+	* @param reducer a commutative associative combining function
3533	+	* @return the result of accumulating the given transformation
3534	+	* of all keys
3535	+	*/
3536	+	public long reduceKeysToLong(long parallelismThreshold,
3537	+	ToLongFunction<? super K> transformer,
3538	+	long basis,
3539	+	LongBinaryOperator reducer) {
3540	+	if (transformer == null || reducer == null)
3541	+	throw new NullPointerException();
3542	+	return new MapReduceKeysToLongTask<K,V>
3543	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3544	+	null, transformer, basis, reducer).invoke();
3545	+	}
3546	+
3547	+	/**
3548	+	* Returns the result of accumulating the given transformation
3549	+	* of all keys using the given reducer to combine values, and
3550	+	* the given basis as an identity value.
3551	+	*
3552	+	* @param parallelismThreshold the (estimated) number of elements
3553	+	* needed for this operation to be executed in parallel
3554	+	* @param transformer a function returning the transformation
3555	+	* for an element
3556	+	* @param basis the identity (initial default value) for the reduction
3557	+	* @param reducer a commutative associative combining function
3558	+	* @return the result of accumulating the given transformation
3559	+	* of all keys
3560	+	*/
3561	+	public int reduceKeysToInt(long parallelismThreshold,
3562	+	ToIntFunction<? super K> transformer,
3563	+	int basis,
3564	+	IntBinaryOperator reducer) {
3565	+	if (transformer == null || reducer == null)
3566	+	throw new NullPointerException();
3567	+	return new MapReduceKeysToIntTask<K,V>
3568	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3569	+	null, transformer, basis, reducer).invoke();
3570	+	}
3571	+
3572	+	/**
3573	+	* Performs the given action for each value.
3574	+	*
3575	+	* @param parallelismThreshold the (estimated) number of elements
3576	+	* needed for this operation to be executed in parallel
3577	+	* @param action the action
3578	+	*/
3579	+	public void forEachValue(long parallelismThreshold,
3580	+	Consumer<? super V> action) {
3581	+	if (action == null)
3582	+	throw new NullPointerException();
3583	+	new ForEachValueTask<K,V>
3584	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3585	+	action).invoke();
3586	+	}
3587	+
3588	+	/**
3589	+	* Performs the given action for each non-null transformation
3590	+	* of each value.
3591	+	*
3592	+	* @param parallelismThreshold the (estimated) number of elements
3593	+	* needed for this operation to be executed in parallel
3594	+	* @param transformer a function returning the transformation
3595	+	* for an element, or null if there is no transformation (in
3596	+	* which case the action is not applied)
3597	+	* @param action the action
3598	+	*/
3599	+	public <U> void forEachValue(long parallelismThreshold,
3600	+	Function<? super V, ? extends U> transformer,
3601	+	Consumer<? super U> action) {
3602	+	if (transformer == null || action == null)
3603	+	throw new NullPointerException();
3604	+	new ForEachTransformedValueTask<K,V,U>
3605	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3606	+	transformer, action).invoke();
3607	+	}
3608	+
3609	+	/**
3610	+	* Returns a non-null result from applying the given search
3611	+	* function on each value, or null if none.  Upon success,
3612	+	* further element processing is suppressed and the results of
3613	+	* any other parallel invocations of the search function are
3614	+	* ignored.
3615	+	*
3616	+	* @param parallelismThreshold the (estimated) number of elements
3617	+	* needed for this operation to be executed in parallel
3618	+	* @param searchFunction a function returning a non-null
3619	+	* result on success, else null
3620	+	* @return a non-null result from applying the given search
3621	+	* function on each value, or null if none
3622	+	*/
3623	+	public <U> U searchValues(long parallelismThreshold,
3624	+	Function<? super V, ? extends U> searchFunction) {
3625	+	if (searchFunction == null) throw new NullPointerException();
3626	+	return new SearchValuesTask<K,V,U>
3627	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3628	+	searchFunction, new AtomicReference<U>()).invoke();
3629	+	}
3630	+
3631	+	/**
3632	+	* Returns the result of accumulating all values using the
3633	+	* given reducer to combine values, or null if none.
3634	+	*
3635	+	* @param parallelismThreshold the (estimated) number of elements
3636	+	* needed for this operation to be executed in parallel
3637	+	* @param reducer a commutative associative combining function
3638	+	* @return the result of accumulating all values
3639	+	*/
3640	+	public V reduceValues(long parallelismThreshold,
3641	+	BiFunction<? super V, ? super V, ? extends V> reducer) {
3642	+	if (reducer == null) throw new NullPointerException();
3643	+	return new ReduceValuesTask<K,V>
3644	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3645	+	null, reducer).invoke();
3646	+	}
3647	+
3648	+	/**
3649	+	* Returns the result of accumulating the given transformation
3650	+	* of all values using the given reducer to combine values, or
3651	+	* null if none.
3652	+	*
3653	+	* @param parallelismThreshold the (estimated) number of elements
3654	+	* needed for this operation to be executed in parallel
3655	+	* @param transformer a function returning the transformation
3656	+	* for an element, or null if there is no transformation (in
3657	+	* which case it is not combined)
3658	+	* @param reducer a commutative associative combining function
3659	+	* @return the result of accumulating the given transformation
3660	+	* of all values
3661	+	*/
3662	+	public <U> U reduceValues(long parallelismThreshold,
3663	+	Function<? super V, ? extends U> transformer,
3664	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
3665	+	if (transformer == null || reducer == null)
3666	+	throw new NullPointerException();
3667	+	return new MapReduceValuesTask<K,V,U>
3668	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3669	+	null, transformer, reducer).invoke();
3670	+	}
3671	+
3672	+	/**
3673	+	* Returns the result of accumulating the given transformation
3674	+	* of all values using the given reducer to combine values,
3675	+	* and the given basis as an identity value.
3676	+	*
3677	+	* @param parallelismThreshold the (estimated) number of elements
3678	+	* needed for this operation to be executed in parallel
3679	+	* @param transformer a function returning the transformation
3680	+	* for an element
3681	+	* @param basis the identity (initial default value) for the reduction
3682	+	* @param reducer a commutative associative combining function
3683	+	* @return the result of accumulating the given transformation
3684	+	* of all values
3685	+	*/
3686	+	public double reduceValuesToDouble(long parallelismThreshold,
3687	+	ToDoubleFunction<? super V> transformer,
3688	+	double basis,
3689	+	DoubleBinaryOperator reducer) {
3690	+	if (transformer == null || reducer == null)
3691	+	throw new NullPointerException();
3692	+	return new MapReduceValuesToDoubleTask<K,V>
3693	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3694	+	null, transformer, basis, reducer).invoke();
3695	+	}
3696	+
3697	+	/**
3698	+	* Returns the result of accumulating the given transformation
3699	+	* of all values using the given reducer to combine values,
3700	+	* and the given basis as an identity value.
3701	+	*
3702	+	* @param parallelismThreshold the (estimated) number of elements
3703	+	* needed for this operation to be executed in parallel
3704	+	* @param transformer a function returning the transformation
3705	+	* for an element
3706	+	* @param basis the identity (initial default value) for the reduction
3707	+	* @param reducer a commutative associative combining function
3708	+	* @return the result of accumulating the given transformation
3709	+	* of all values
3710	+	*/
3711	+	public long reduceValuesToLong(long parallelismThreshold,
3712	+	ToLongFunction<? super V> transformer,
3713	+	long basis,
3714	+	LongBinaryOperator reducer) {
3715	+	if (transformer == null || reducer == null)
3716	+	throw new NullPointerException();
3717	+	return new MapReduceValuesToLongTask<K,V>
3718	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3719	+	null, transformer, basis, reducer).invoke();
3720	+	}
3721	+
3722	+	/**
3723	+	* Returns the result of accumulating the given transformation
3724	+	* of all values using the given reducer to combine values,
3725	+	* and the given basis as an identity value.
3726	+	*
3727	+	* @param parallelismThreshold the (estimated) number of elements
3728	+	* needed for this operation to be executed in parallel
3729	+	* @param transformer a function returning the transformation
3730	+	* for an element
3731	+	* @param basis the identity (initial default value) for the reduction
3732	+	* @param reducer a commutative associative combining function
3733	+	* @return the result of accumulating the given transformation
3734	+	* of all values
3735	+	*/
3736	+	public int reduceValuesToInt(long parallelismThreshold,
3737	+	ToIntFunction<? super V> transformer,
3738	+	int basis,
3739	+	IntBinaryOperator reducer) {
3740	+	if (transformer == null || reducer == null)
3741	+	throw new NullPointerException();
3742	+	return new MapReduceValuesToIntTask<K,V>
3743	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3744	+	null, transformer, basis, reducer).invoke();
3745	+	}
3746	+
3747	+	/**
3748	+	* Performs the given action for each entry.
3749	+	*
3750	+	* @param parallelismThreshold the (estimated) number of elements
3751	+	* needed for this operation to be executed in parallel
3752	+	* @param action the action
3753	+	*/
3754	+	public void forEachEntry(long parallelismThreshold,
3755	+	Consumer<? super Map.Entry<K,V>> action) {
3756	+	if (action == null) throw new NullPointerException();
3757	+	new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table,
3758	+	action).invoke();
3759	+	}
3760	+
3761	+	/**
3762	+	* Performs the given action for each non-null transformation
3763	+	* of each entry.
3764	+	*
3765	+	* @param parallelismThreshold the (estimated) number of elements
3766	+	* needed for this operation to be executed in parallel
3767	+	* @param transformer a function returning the transformation
3768	+	* for an element, or null if there is no transformation (in
3769	+	* which case the action is not applied)
3770	+	* @param action the action
3771	+	*/
3772	+	public <U> void forEachEntry(long parallelismThreshold,
3773	+	Function<Map.Entry<K,V>, ? extends U> transformer,
3774	+	Consumer<? super U> action) {
3775	+	if (transformer == null || action == null)
3776	+	throw new NullPointerException();
3777	+	new ForEachTransformedEntryTask<K,V,U>
3778	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3779	+	transformer, action).invoke();
3780	+	}
3781	+
3782	+	/**
3783	+	* Returns a non-null result from applying the given search
3784	+	* function on each entry, or null if none.  Upon success,
3785	+	* further element processing is suppressed and the results of
3786	+	* any other parallel invocations of the search function are
3787	+	* ignored.
3788	+	*
3789	+	* @param parallelismThreshold the (estimated) number of elements
3790	+	* needed for this operation to be executed in parallel
3791	+	* @param searchFunction a function returning a non-null
3792	+	* result on success, else null
3793	+	* @return a non-null result from applying the given search
3794	+	* function on each entry, or null if none
3795	+	*/
3796	+	public <U> U searchEntries(long parallelismThreshold,
3797	+	Function<Map.Entry<K,V>, ? extends U> searchFunction) {
3798	+	if (searchFunction == null) throw new NullPointerException();
3799	+	return new SearchEntriesTask<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 entries using the
3806	+	* given 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 entries
3812	+	*/
3813	+	public Map.Entry<K,V> reduceEntries(long parallelismThreshold,
3814	+	BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
3815	+	if (reducer == null) throw new NullPointerException();
3816	+	return new ReduceEntriesTask<K,V>
3817	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3818	+	null, reducer).invoke();
3819	+	}
3820	+
3821	+	/**
3822	+	* Returns the result of accumulating the given transformation
3823	+	* of all entries using the given reducer to combine values,
3824	+	* or null if none.
3825	+	*
3826	+	* @param parallelismThreshold the (estimated) number of elements
3827	+	* needed for this operation to be executed in parallel
3828	+	* @param transformer a function returning the transformation
3829	+	* for an element, or null if there is no transformation (in
3830	+	* which case it is not combined)
3831	+	* @param reducer a commutative associative combining function
3832	+	* @return the result of accumulating the given transformation
3833	+	* of all entries
3834	+	*/
3835	+	public <U> U reduceEntries(long parallelismThreshold,
3836	+	Function<Map.Entry<K,V>, ? extends U> transformer,
3837	+	BiFunction<? super U, ? super U, ? extends U> reducer) {
3838	+	if (transformer == null || reducer == null)
3839	+	throw new NullPointerException();
3840	+	return new MapReduceEntriesTask<K,V,U>
3841	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3842	+	null, transformer, reducer).invoke();
3843	+	}
3844	+
3845	+	/**
3846	+	* Returns the result of accumulating the given transformation
3847	+	* of all entries using the given reducer to combine values,
3848	+	* and the given basis as an identity value.
3849	+	*
3850	+	* @param parallelismThreshold the (estimated) number of elements
3851	+	* needed for this operation to be executed in parallel
3852	+	* @param transformer a function returning the transformation
3853	+	* for an element
3854	+	* @param basis the identity (initial default value) for the reduction
3855	+	* @param reducer a commutative associative combining function
3856	+	* @return the result of accumulating the given transformation
3857	+	* of all entries
3858	+	*/
3859	+	public double reduceEntriesToDouble(long parallelismThreshold,
3860	+	ToDoubleFunction<Map.Entry<K,V>> transformer,
3861	+	double basis,
3862	+	DoubleBinaryOperator reducer) {
3863	+	if (transformer == null || reducer == null)
3864	+	throw new NullPointerException();
3865	+	return new MapReduceEntriesToDoubleTask<K,V>
3866	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3867	+	null, transformer, basis, reducer).invoke();
3868	+	}
3869	+
3870	+	/**
3871	+	* Returns the result of accumulating the given transformation
3872	+	* of all entries using the given reducer to combine values,
3873	+	* and the given basis as an identity value.
3874	+	*
3875	+	* @param parallelismThreshold the (estimated) number of elements
3876	+	* needed for this operation to be executed in parallel
3877	+	* @param transformer a function returning the transformation
3878	+	* for an element
3879	+	* @param basis the identity (initial default value) for the reduction
3880	+	* @param reducer a commutative associative combining function
3881	+	* @return the result of accumulating the given transformation
3882	+	* of all entries
3883	+	*/
3884	+	public long reduceEntriesToLong(long parallelismThreshold,
3885	+	ToLongFunction<Map.Entry<K,V>> transformer,
3886	+	long basis,
3887	+	LongBinaryOperator reducer) {
3888	+	if (transformer == null || reducer == null)
3889	+	throw new NullPointerException();
3890	+	return new MapReduceEntriesToLongTask<K,V>
3891	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3892	+	null, transformer, basis, reducer).invoke();
3893	+	}
3894	+
3895	+	/**
3896	+	* Returns the result of accumulating the given transformation
3897	+	* of all entries using the given reducer to combine values,
3898	+	* and the given basis as an identity value.
3899	+	*
3900	+	* @param parallelismThreshold the (estimated) number of elements
3901	+	* needed for this operation to be executed in parallel
3902	+	* @param transformer a function returning the transformation
3903	+	* for an element
3904	+	* @param basis the identity (initial default value) for the reduction
3905	+	* @param reducer a commutative associative combining function
3906	+	* @return the result of accumulating the given transformation
3907	+	* of all entries
3908	+	*/
3909	+	public int reduceEntriesToInt(long parallelismThreshold,
3910	+	ToIntFunction<Map.Entry<K,V>> transformer,
3911	+	int basis,
3912	+	IntBinaryOperator reducer) {
3913	+	if (transformer == null || reducer == null)
3914	+	throw new NullPointerException();
3915	+	return new MapReduceEntriesToIntTask<K,V>
3916	+	(null, batchFor(parallelismThreshold), 0, 0, table,
3917	+	null, transformer, basis, reducer).invoke();
3918	+	}
3919	+
3920	+
3921	+	/* ----------------Views -------------- */
3922	+
3923	+	/**
3924	+	* Base class for views.
3925	+	*/
3926	+	abstract static class CollectionView<K,V,E>
3927	+	implements Collection<E>, java.io.Serializable {
3928	+	private static final long serialVersionUID = 7249069246763182397L;
3929	+	final ConcurrentHashMap<K,V> map;
3930	+	CollectionView(ConcurrentHashMap<K,V> map)  { this.map = map; }
3931	+
3932	+	/**
3933	+	* Returns the map backing this view.
3934	+	*
3935	+	* @return the map backing this view
3936	+	*/
3937	+	public ConcurrentHashMap<K,V> getMap() { return map; }
3938
3939		/**
3940	<	* Sets nextEntry to first node of next non-empty table
3941	<	* (in backwards order, to simplify checks).
3940	>	* Removes all of the elements from this view, by removing all
3941	>	* the mappings from the map backing this view.
3942		*/
3943	<	final void advance() {
3944	<	for (;;) {
3945	<	if (nextTableIndex >= 0) {
3946	<	if ((nextEntry = entryAt(currentTable,
3947	<	nextTableIndex--)) != null)
3943	>	public final void clear()      { map.clear(); }
3944	>	public final int size()        { return map.size(); }
3945	>	public final boolean isEmpty() { return map.isEmpty(); }
3946	>
3947	>	// implementations below rely on concrete classes supplying these
3948	>	// abstract methods
3949	>	/**
3950	>	* Returns a "weakly consistent" iterator that will never
3951	>	* throw {@link ConcurrentModificationException}, and
3952	>	* guarantees to traverse elements as they existed upon
3953	>	* construction of the iterator, and may (but is not
3954	>	* guaranteed to) reflect any modifications subsequent to
3955	>	* construction.
3956	>	*/
3957	>	public abstract Iterator<E> iterator();
3958	>	public abstract boolean contains(Object o);
3959	>	public abstract boolean remove(Object o);
3960	>
3961	>	private static final String oomeMsg = "Required array size too large";
3962	>
3963	>	public final Object[] toArray() {
3964	>	long sz = map.mappingCount();
3965	>	if (sz > MAX_ARRAY_SIZE)
3966	>	throw new OutOfMemoryError(oomeMsg);
3967	>	int n = (int)sz;
3968	>	Object[] r = new Object[n];
3969	>	int i = 0;
3970	>	for (E e : this) {
3971	>	if (i == n) {
3972	>	if (n >= MAX_ARRAY_SIZE)
3973	>	throw new OutOfMemoryError(oomeMsg);
3974	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3975	>	n = MAX_ARRAY_SIZE;
3976	>	else
3977	>	n += (n >>> 1) + 1;
3978	>	r = Arrays.copyOf(r, n);
3979	>	}
3980	>	r[i++] = e;
3981	>	}
3982	>	return (i == n) ? r : Arrays.copyOf(r, i);
3983	>	}
3984	>
3985	>	public final <T> T[] toArray(T[] a) {
3986	>	long sz = map.mappingCount();
3987	>	if (sz > MAX_ARRAY_SIZE)
3988	>	throw new OutOfMemoryError(oomeMsg);
3989	>	int m = (int)sz;
3990	>	T[] r = (a.length >= m) ? a :
3991	>	(T[])java.lang.reflect.Array
3992	>	.newInstance(a.getClass().getComponentType(), m);
3993	>	int n = r.length;
3994	>	int i = 0;
3995	>	for (E e : this) {
3996	>	if (i == n) {
3997	>	if (n >= MAX_ARRAY_SIZE)
3998	>	throw new OutOfMemoryError(oomeMsg);
3999	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
4000	>	n = MAX_ARRAY_SIZE;
4001	>	else
4002	>	n += (n >>> 1) + 1;
4003	>	r = Arrays.copyOf(r, n);
4004	>	}
4005	>	r[i++] = (T)e;
4006	>	}
4007	>	if (a == r && i < n) {
4008	>	r[i] = null; // null-terminate
4009	>	return r;
4010	>	}
4011	>	return (i == n) ? r : Arrays.copyOf(r, i);
4012	>	}
4013	>
4014	>	/**
4015	>	* Returns a string representation of this collection.
4016	>	* The string representation consists of the string representations
4017	>	* of the collection's elements in the order they are returned by
4018	>	* its iterator, enclosed in square brackets ({@code "[]"}).
4019	>	* Adjacent elements are separated by the characters {@code ", "}
4020	>	* (comma and space).  Elements are converted to strings as by
4021	>	* {@link String#valueOf(Object)}.
4022	>	*
4023	>	* @return a string representation of this collection
4024	>	*/
4025	>	public final String toString() {
4026	>	StringBuilder sb = new StringBuilder();
4027	>	sb.append('[');
4028	>	Iterator<E> it = iterator();
4029	>	if (it.hasNext()) {
4030	>	for (;;) {
4031	>	Object e = it.next();
4032	>	sb.append(e == this ? "(this Collection)" : e);
4033	>	if (!it.hasNext())
4034		break;
4035	+	sb.append(',').append(' ');
4036		}
4037	<	else if (nextSegmentIndex >= 0) {
4038	<	Segment<K,V> seg = segmentAt(segments, nextSegmentIndex--);
4039	<	if (seg != null && (currentTable = seg.table) != null)
4040	<	nextTableIndex = currentTable.length - 1;
4037	>	}
4038	>	return sb.append(']').toString();
4039	>	}
4040	>
4041	>	public final boolean containsAll(Collection<?> c) {
4042	>	if (c != this) {
4043	>	for (Object e : c) {
4044	>	if (e == null || !contains(e))
4045	>	return false;
4046		}
1250	–	else
1251	–	break;
4047		}
4048	+	return true;
4049		}
4050
4051	<	final HashEntry<K,V> nextEntry() {
4052	<	HashEntry<K,V> e = nextEntry;
4053	<	if (e == null)
4054	<	throw new NoSuchElementException();
4055	<	lastReturned = e; // cannot assign until after null check
4056	<	if ((nextEntry = e.next) == null)
4057	<	advance();
4058	<	return e;
4051	>	public final boolean removeAll(Collection<?> c) {
4052	>	boolean modified = false;
4053	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4054	>	if (c.contains(it.next())) {
4055	>	it.remove();
4056	>	modified = true;
4057	>	}
4058	>	}
4059	>	return modified;
4060		}
4061
4062	<	public final boolean hasNext() { return nextEntry != null; }
4063	<	public final boolean hasMoreElements() { return nextEntry != null; }
4062	>	public final boolean retainAll(Collection<?> c) {
4063	>	boolean modified = false;
4064	>	for (Iterator<E> it = iterator(); it.hasNext();) {
4065	>	if (!c.contains(it.next())) {
4066	>	it.remove();
4067	>	modified = true;
4068	>	}
4069	>	}
4070	>	return modified;
4071	>	}
4072
4073	<	public final void remove() {
4074	<	if (lastReturned == null)
4075	<	throw new IllegalStateException();
4076	<	ConcurrentHashMap.this.remove(lastReturned.key);
4077	<	lastReturned = null;
4073	>	}
4074	>
4075	>	/**
4076	>	* A view of a ConcurrentHashMap as a {@link Set} of keys, in
4077	>	* which additions may optionally be enabled by mapping to a
4078	>	* common value.  This class cannot be directly instantiated.
4079	>	* See {@link #keySet() keySet()},
4080	>	* {@link #keySet(Object) keySet(V)},
4081	>	* {@link #newKeySet() newKeySet()},
4082	>	* {@link #newKeySet(int) newKeySet(int)}.
4083	>	*/
4084	>	public static class KeySetView<K,V> extends CollectionView<K,V,K>
4085	>	implements Set<K>, java.io.Serializable {
4086	>	private static final long serialVersionUID = 7249069246763182397L;
4087	>	private final V value;
4088	>	KeySetView(ConcurrentHashMap<K,V> map, V value) {  // non-public
4089	>	super(map);
4090	>	this.value = value;
4091	>	}
4092	>
4093	>	/**
4094	>	* Returns the default mapped value for additions,
4095	>	* or {@code null} if additions are not supported.
4096	>	*
4097	>	* @return the default mapped value for additions, or {@code null}
4098	>	* if not supported
4099	>	*/
4100	>	public V getMappedValue() { return value; }
4101	>
4102	>	/**
4103	>	* {@inheritDoc}
4104	>	* @throws NullPointerException if the specified key is null
4105	>	*/
4106	>	public boolean contains(Object o) { return map.containsKey(o); }
4107	>
4108	>	/**
4109	>	* Removes the key from this map view, by removing the key (and its
4110	>	* corresponding value) from the backing map.  This method does
4111	>	* nothing if the key is not in the map.
4112	>	*
4113	>	* @param  o the key to be removed from the backing map
4114	>	* @return {@code true} if the backing map contained the specified key
4115	>	* @throws NullPointerException if the specified key is null
4116	>	*/
4117	>	public boolean remove(Object o) { return map.remove(o) != null; }
4118	>
4119	>	/**
4120	>	* @return an iterator over the keys of the backing map
4121	>	*/
4122	>	public Iterator<K> iterator() {
4123	>	Node<K,V>[] t;
4124	>	ConcurrentHashMap<K,V> m = map;
4125	>	int f = (t = m.table) == null ? 0 : t.length;
4126	>	return new KeyIterator<K,V>(t, f, 0, f, m);
4127	>	}
4128	>
4129	>	/**
4130	>	* Adds the specified key to this set view by mapping the key to
4131	>	* the default mapped value in the backing map, if defined.
4132	>	*
4133	>	* @param e key to be added
4134	>	* @return {@code true} if this set changed as a result of the call
4135	>	* @throws NullPointerException if the specified key is null
4136	>	* @throws UnsupportedOperationException if no default mapped value
4137	>	* for additions was provided
4138	>	*/
4139	>	public boolean add(K e) {
4140	>	V v;
4141	>	if ((v = value) == null)
4142	>	throw new UnsupportedOperationException();
4143	>	return map.internalPut(e, v, true) == null;
4144	>	}
4145	>
4146	>	/**
4147	>	* Adds all of the elements in the specified collection to this set,
4148	>	* as if by calling {@link #add} on each one.
4149	>	*
4150	>	* @param c the elements to be inserted into this set
4151	>	* @return {@code true} if this set changed as a result of the call
4152	>	* @throws NullPointerException if the collection or any of its
4153	>	* elements are {@code null}
4154	>	* @throws UnsupportedOperationException if no default mapped value
4155	>	* for additions was provided
4156	>	*/
4157	>	public boolean addAll(Collection<? extends K> c) {
4158	>	boolean added = false;
4159	>	V v;
4160	>	if ((v = value) == null)
4161	>	throw new UnsupportedOperationException();
4162	>	for (K e : c) {
4163	>	if (map.internalPut(e, v, true) == null)
4164	>	added = true;
4165	>	}
4166	>	return added;
4167	>	}
4168	>
4169	>	public int hashCode() {
4170	>	int h = 0;
4171	>	for (K e : this)
4172	>	h += e.hashCode();
4173	>	return h;
4174	>	}
4175	>
4176	>	public boolean equals(Object o) {
4177	>	Set<?> c;
4178	>	return ((o instanceof Set) &&
4179	>	((c = (Set<?>)o) == this ||
4180	>	(containsAll(c) && c.containsAll(this))));
4181	>	}
4182	>
4183	>	public Spliterator<K> spliterator() {
4184	>	Node<K,V>[] t;
4185	>	ConcurrentHashMap<K,V> m = map;
4186	>	long n = m.sumCount();
4187	>	int f = (t = m.table) == null ? 0 : t.length;
4188	>	return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4189	>	}
4190	>
4191	>	public void forEach(Consumer<? super K> action) {
4192	>	if (action == null) throw new NullPointerException();
4193	>	Node<K,V>[] t;
4194	>	if ((t = map.table) != null) {
4195	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4196	>	for (Node<K,V> p; (p = it.advance()) != null; )
4197	>	action.accept((K)p.key);
4198	>	}
4199		}
4200		}
4201
4202	<	final class KeyIterator
4203	<	extends HashIterator
4204	<	implements Iterator<K>, Enumeration<K>
4205	<	{
4206	<	public final K next()        { return super.nextEntry().key; }
4207	<	public final K nextElement() { return super.nextEntry().key; }
4208	<	}
4209	<
4210	<	final class ValueIterator
4211	<	extends HashIterator
4212	<	implements Iterator<V>, Enumeration<V>
4213	<	{
4214	<	public final V next()        { return super.nextEntry().value; }
4215	<	public final V nextElement() { return super.nextEntry().value; }
4202	>	/**
4203	>	* A view of a ConcurrentHashMap as a {@link Collection} of
4204	>	* values, in which additions are disabled. This class cannot be
4205	>	* directly instantiated. See {@link #values()}.
4206	>	*/
4207	>	static final class ValuesView<K,V> extends CollectionView<K,V,V>
4208	>	implements Collection<V>, java.io.Serializable {
4209	>	private static final long serialVersionUID = 2249069246763182397L;
4210	>	ValuesView(ConcurrentHashMap<K,V> map) { super(map); }
4211	>	public final boolean contains(Object o) {
4212	>	return map.containsValue(o);
4213	>	}
4214	>
4215	>	public final boolean remove(Object o) {
4216	>	if (o != null) {
4217	>	for (Iterator<V> it = iterator(); it.hasNext();) {
4218	>	if (o.equals(it.next())) {
4219	>	it.remove();
4220	>	return true;
4221	>	}
4222	>	}
4223	>	}
4224	>	return false;
4225	>	}
4226	>
4227	>	public final Iterator<V> iterator() {
4228	>	ConcurrentHashMap<K,V> m = map;
4229	>	Node<K,V>[] t;
4230	>	int f = (t = m.table) == null ? 0 : t.length;
4231	>	return new ValueIterator<K,V>(t, f, 0, f, m);
4232	>	}
4233	>
4234	>	public final boolean add(V e) {
4235	>	throw new UnsupportedOperationException();
4236	>	}
4237	>	public final boolean addAll(Collection<? extends V> c) {
4238	>	throw new UnsupportedOperationException();
4239	>	}
4240	>
4241	>	public Spliterator<V> spliterator() {
4242	>	Node<K,V>[] t;
4243	>	ConcurrentHashMap<K,V> m = map;
4244	>	long n = m.sumCount();
4245	>	int f = (t = m.table) == null ? 0 : t.length;
4246	>	return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n);
4247	>	}
4248	>
4249	>	public void forEach(Consumer<? super V> action) {
4250	>	if (action == null) throw new NullPointerException();
4251	>	Node<K,V>[] t;
4252	>	if ((t = map.table) != null) {
4253	>	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4254	>	for (Node<K,V> p; (p = it.advance()) != null; )
4255	>	action.accept(p.val);
4256	>	}
4257	>	}
4258		}
4259
4260		/**
4261	<	* Custom Entry class used by EntryIterator.next(), that relays
4262	<	* setValue changes to the underlying map.
4263	<	*/
4264	<	final class WriteThroughEntry
4265	<	extends AbstractMap.SimpleEntry<K,V>
4266	<	{
4267	<	WriteThroughEntry(K k, V v) {
4268	<	super(k,v);
4261	>	* A view of a ConcurrentHashMap as a {@link Set} of (key, value)
4262	>	* entries.  This class cannot be directly instantiated. See
4263	>	* {@link #entrySet()}.
4264	>	*/
4265	>	static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>>
4266	>	implements Set<Map.Entry<K,V>>, java.io.Serializable {
4267	>	private static final long serialVersionUID = 2249069246763182397L;
4268	>	EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
4269	>
4270	>	public boolean contains(Object o) {
4271	>	Object k, v, r; Map.Entry<?,?> e;
4272	>	return ((o instanceof Map.Entry) &&
4273	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4274	>	(r = map.get(k)) != null &&
4275	>	(v = e.getValue()) != null &&
4276	>	(v == r || v.equals(r)));
4277	>	}
4278	>
4279	>	public boolean remove(Object o) {
4280	>	Object k, v; Map.Entry<?,?> e;
4281	>	return ((o instanceof Map.Entry) &&
4282	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
4283	>	(v = e.getValue()) != null &&
4284	>	map.remove(k, v));
4285		}
4286
4287		/**
4288	<	* Sets our entry's value and writes through to the map. The
1305	<	* value to return is somewhat arbitrary here. Since a
1306	<	* WriteThroughEntry does not necessarily track asynchronous
1307	<	* changes, the most recent "previous" value could be
1308	<	* different from what we return (or could even have been
1309	<	* removed in which case the put will re-establish). We do not
1310	<	* and cannot guarantee more.
4288	>	* @return an iterator over the entries of the backing map
4289		*/
4290	<	public V setValue(V value) {
4291	<	if (value == null) throw new NullPointerException();
4292	<	V v = super.setValue(value);
4293	<	ConcurrentHashMap.this.put(getKey(), value);
4294	<	return v;
4290	>	public Iterator<Map.Entry<K,V>> iterator() {
4291	>	ConcurrentHashMap<K,V> m = map;
4292	>	Node<K,V>[] t;
4293	>	int f = (t = m.table) == null ? 0 : t.length;
4294	>	return new EntryIterator<K,V>(t, f, 0, f, m);
4295	>	}
4296	>
4297	>	public boolean add(Entry<K,V> e) {
4298	>	return map.internalPut(e.getKey(), e.getValue(), false) == null;
4299		}
4300	+
4301	+	public boolean addAll(Collection<? extends Entry<K,V>> c) {
4302	+	boolean added = false;
4303	+	for (Entry<K,V> e : c) {
4304	+	if (add(e))
4305	+	added = true;
4306	+	}
4307	+	return added;
4308	+	}
4309	+
4310	+	public final int hashCode() {
4311	+	int h = 0;
4312	+	Node<K,V>[] t;
4313	+	if ((t = map.table) != null) {
4314	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4315	+	for (Node<K,V> p; (p = it.advance()) != null; ) {
4316	+	h += p.hashCode();
4317	+	}
4318	+	}
4319	+	return h;
4320	+	}
4321	+
4322	+	public final boolean equals(Object o) {
4323	+	Set<?> c;
4324	+	return ((o instanceof Set) &&
4325	+	((c = (Set<?>)o) == this ||
4326	+	(containsAll(c) && c.containsAll(this))));
4327	+	}
4328	+
4329	+	public Spliterator<Map.Entry<K,V>> spliterator() {
4330	+	Node<K,V>[] t;
4331	+	ConcurrentHashMap<K,V> m = map;
4332	+	long n = m.sumCount();
4333	+	int f = (t = m.table) == null ? 0 : t.length;
4334	+	return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m);
4335	+	}
4336	+
4337	+	public void forEach(Consumer<? super Map.Entry<K,V>> action) {
4338	+	if (action == null) throw new NullPointerException();
4339	+	Node<K,V>[] t;
4340	+	if ((t = map.table) != null) {
4341	+	Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
4342	+	for (Node<K,V> p; (p = it.advance()) != null; )
4343	+	action.accept(new MapEntry<K,V>((K)p.key, p.val, map));
4344	+	}
4345	+	}
4346	+
4347		}
4348
4349	<	final class EntryIterator
4350	<	extends HashIterator
4351	<	implements Iterator<Entry<K,V>>
4352	<	{
4353	<	public Map.Entry<K,V> next() {
4354	<	HashEntry<K,V> e = super.nextEntry();
4355	<	return new WriteThroughEntry(e.key, e.value);
4349	>	// -------------------------------------------------------
4350	>
4351	>	/**
4352	>	* Base class for bulk tasks. Repeats some fields and code from
4353	>	* class Traverser, because we need to subclass CountedCompleter.
4354	>	*/
4355	>	abstract static class BulkTask<K,V,R> extends CountedCompleter<R> {
4356	>	Node<K,V>[] tab;        // same as Traverser
4357	>	Node<K,V> next;
4358	>	int index;
4359	>	int baseIndex;
4360	>	int baseLimit;
4361	>	final int baseSize;
4362	>	int batch;              // split control
4363	>
4364	>	BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) {
4365	>	super(par);
4366	>	this.batch = b;
4367	>	this.index = this.baseIndex = i;
4368	>	if ((this.tab = t) == null)
4369	>	this.baseSize = this.baseLimit = 0;
4370	>	else if (par == null)
4371	>	this.baseSize = this.baseLimit = t.length;
4372	>	else {
4373	>	this.baseLimit = f;
4374	>	this.baseSize = par.baseSize;
4375	>	}
4376	>	}
4377	>
4378	>	/**
4379	>	* Same as Traverser version
4380	>	*/
4381	>	final Node<K,V> advance() {
4382	>	Node<K,V> e;
4383	>	if ((e = next) != null)
4384	>	e = e.next;
4385	>	for (;;) {
4386	>	Node<K,V>[] t; int i, n; Object ek;
4387	>	if (e != null)
4388	>	return next = e;
4389	>	if (baseIndex >= baseLimit || (t = tab) == null ||
4390	>	(n = t.length) <= (i = index) || i < 0)
4391	>	return next = null;
4392	>	if ((e = tabAt(t, index)) != null && e.hash < 0) {
4393	>	if ((ek = e.key) instanceof TreeBin)
4394	>	e = ((TreeBin<K,V>)ek).first;
4395	>	else {
4396	>	tab = (Node<K,V>[])ek;
4397	>	e = null;
4398	>	continue;
4399	>	}
4400	>	}
4401	>	if ((index += baseSize) >= n)
4402	>	index = ++baseIndex;
4403	>	}
4404		}
4405		}
4406
4407	<	final class KeySet extends AbstractSet<K> {
4408	<	public Iterator<K> iterator() {
4409	<	return new KeyIterator();
4407	>	/*
4408	>	* Task classes. Coded in a regular but ugly format/style to
4409	>	* simplify checks that each variant differs in the right way from
4410	>	* others. The null screenings exist because compilers cannot tell
4411	>	* that we've already null-checked task arguments, so we force
4412	>	* simplest hoisted bypass to help avoid convoluted traps.
4413	>	*/
4414	>
4415	>	static final class ForEachKeyTask<K,V>
4416	>	extends BulkTask<K,V,Void> {
4417	>	final Consumer<? super K> action;
4418	>	ForEachKeyTask
4419	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4420	>	Consumer<? super K> action) {
4421	>	super(p, b, i, f, t);
4422	>	this.action = action;
4423	>	}
4424	>	public final void compute() {
4425	>	final Consumer<? super K> action;
4426	>	if ((action = this.action) != null) {
4427	>	for (int i = baseIndex, f, h; batch > 0 &&
4428	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4429	>	addToPendingCount(1);
4430	>	new ForEachKeyTask<K,V>
4431	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4432	>	action).fork();
4433	>	}
4434	>	for (Node<K,V> p; (p = advance()) != null;)
4435	>	action.accept((K)p.key);
4436	>	propagateCompletion();
4437	>	}
4438		}
4439	<	public int size() {
4440	<	return ConcurrentHashMap.this.size();
4439	>	}
4440	>
4441	>	static final class ForEachValueTask<K,V>
4442	>	extends BulkTask<K,V,Void> {
4443	>	final Consumer<? super V> action;
4444	>	ForEachValueTask
4445	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4446	>	Consumer<? super V> action) {
4447	>	super(p, b, i, f, t);
4448	>	this.action = action;
4449	>	}
4450	>	public final void compute() {
4451	>	final Consumer<? super V> action;
4452	>	if ((action = this.action) != null) {
4453	>	for (int i = baseIndex, f, h; batch > 0 &&
4454	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4455	>	addToPendingCount(1);
4456	>	new ForEachValueTask<K,V>
4457	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4458	>	action).fork();
4459	>	}
4460	>	for (Node<K,V> p; (p = advance()) != null;)
4461	>	action.accept(p.val);
4462	>	propagateCompletion();
4463	>	}
4464		}
4465	<	public boolean isEmpty() {
4466	<	return ConcurrentHashMap.this.isEmpty();
4465	>	}
4466	>
4467	>	static final class ForEachEntryTask<K,V>
4468	>	extends BulkTask<K,V,Void> {
4469	>	final Consumer<? super Entry<K,V>> action;
4470	>	ForEachEntryTask
4471	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4472	>	Consumer<? super Entry<K,V>> action) {
4473	>	super(p, b, i, f, t);
4474	>	this.action = action;
4475	>	}
4476	>	public final void compute() {
4477	>	final Consumer<? super Entry<K,V>> action;
4478	>	if ((action = this.action) != null) {
4479	>	for (int i = baseIndex, f, h; batch > 0 &&
4480	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4481	>	addToPendingCount(1);
4482	>	new ForEachEntryTask<K,V>
4483	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4484	>	action).fork();
4485	>	}
4486	>	for (Node<K,V> p; (p = advance()) != null; )
4487	>	action.accept(p);
4488	>	propagateCompletion();
4489	>	}
4490		}
4491	<	public boolean contains(Object o) {
4492	<	return ConcurrentHashMap.this.containsKey(o);
4491	>	}
4492	>
4493	>	static final class ForEachMappingTask<K,V>
4494	>	extends BulkTask<K,V,Void> {
4495	>	final BiConsumer<? super K, ? super V> action;
4496	>	ForEachMappingTask
4497	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4498	>	BiConsumer<? super K,? super V> action) {
4499	>	super(p, b, i, f, t);
4500	>	this.action = action;
4501	>	}
4502	>	public final void compute() {
4503	>	final BiConsumer<? super K, ? super V> action;
4504	>	if ((action = this.action) != null) {
4505	>	for (int i = baseIndex, f, h; batch > 0 &&
4506	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4507	>	addToPendingCount(1);
4508	>	new ForEachMappingTask<K,V>
4509	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4510	>	action).fork();
4511	>	}
4512	>	for (Node<K,V> p; (p = advance()) != null; )
4513	>	action.accept((K)p.key, p.val);
4514	>	propagateCompletion();
4515	>	}
4516		}
4517	<	public boolean remove(Object o) {
4518	<	return ConcurrentHashMap.this.remove(o) != null;
4517	>	}
4518	>
4519	>	static final class ForEachTransformedKeyTask<K,V,U>
4520	>	extends BulkTask<K,V,Void> {
4521	>	final Function<? super K, ? extends U> transformer;
4522	>	final Consumer<? super U> action;
4523	>	ForEachTransformedKeyTask
4524	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4525	>	Function<? super K, ? extends U> transformer, Consumer<? super U> action) {
4526	>	super(p, b, i, f, t);
4527	>	this.transformer = transformer; this.action = action;
4528	>	}
4529	>	public final void compute() {
4530	>	final Function<? super K, ? extends U> transformer;
4531	>	final Consumer<? super U> action;
4532	>	if ((transformer = this.transformer) != null &&
4533	>	(action = this.action) != null) {
4534	>	for (int i = baseIndex, f, h; batch > 0 &&
4535	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4536	>	addToPendingCount(1);
4537	>	new ForEachTransformedKeyTask<K,V,U>
4538	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4539	>	transformer, action).fork();
4540	>	}
4541	>	for (Node<K,V> p; (p = advance()) != null; ) {
4542	>	U u;
4543	>	if ((u = transformer.apply((K)p.key)) != null)
4544	>	action.accept(u);
4545	>	}
4546	>	propagateCompletion();
4547	>	}
4548		}
4549	<	public void clear() {
4550	<	ConcurrentHashMap.this.clear();
4549	>	}
4550	>
4551	>	static final class ForEachTransformedValueTask<K,V,U>
4552	>	extends BulkTask<K,V,Void> {
4553	>	final Function<? super V, ? extends U> transformer;
4554	>	final Consumer<? super U> action;
4555	>	ForEachTransformedValueTask
4556	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4557	>	Function<? super V, ? extends U> transformer, Consumer<? super U> action) {
4558	>	super(p, b, i, f, t);
4559	>	this.transformer = transformer; this.action = action;
4560	>	}
4561	>	public final void compute() {
4562	>	final Function<? super V, ? extends U> transformer;
4563	>	final Consumer<? super U> action;
4564	>	if ((transformer = this.transformer) != null &&
4565	>	(action = this.action) != null) {
4566	>	for (int i = baseIndex, f, h; batch > 0 &&
4567	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4568	>	addToPendingCount(1);
4569	>	new ForEachTransformedValueTask<K,V,U>
4570	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4571	>	transformer, action).fork();
4572	>	}
4573	>	for (Node<K,V> p; (p = advance()) != null; ) {
4574	>	U u;
4575	>	if ((u = transformer.apply(p.val)) != null)
4576	>	action.accept(u);
4577	>	}
4578	>	propagateCompletion();
4579	>	}
4580		}
4581		}
4582
4583	<	final class Values extends AbstractCollection<V> {
4584	<	public Iterator<V> iterator() {
4585	<	return new ValueIterator();
4583	>	static final class ForEachTransformedEntryTask<K,V,U>
4584	>	extends BulkTask<K,V,Void> {
4585	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
4586	>	final Consumer<? super U> action;
4587	>	ForEachTransformedEntryTask
4588	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4589	>	Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) {
4590	>	super(p, b, i, f, t);
4591	>	this.transformer = transformer; this.action = action;
4592	>	}
4593	>	public final void compute() {
4594	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
4595	>	final Consumer<? super U> action;
4596	>	if ((transformer = this.transformer) != null &&
4597	>	(action = this.action) != null) {
4598	>	for (int i = baseIndex, f, h; batch > 0 &&
4599	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4600	>	addToPendingCount(1);
4601	>	new ForEachTransformedEntryTask<K,V,U>
4602	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4603	>	transformer, action).fork();
4604	>	}
4605	>	for (Node<K,V> p; (p = advance()) != null; ) {
4606	>	U u;
4607	>	if ((u = transformer.apply(p)) != null)
4608	>	action.accept(u);
4609	>	}
4610	>	propagateCompletion();
4611	>	}
4612		}
4613	<	public int size() {
4614	<	return ConcurrentHashMap.this.size();
4613	>	}
4614	>
4615	>	static final class ForEachTransformedMappingTask<K,V,U>
4616	>	extends BulkTask<K,V,Void> {
4617	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
4618	>	final Consumer<? super U> action;
4619	>	ForEachTransformedMappingTask
4620	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4621	>	BiFunction<? super K, ? super V, ? extends U> transformer,
4622	>	Consumer<? super U> action) {
4623	>	super(p, b, i, f, t);
4624	>	this.transformer = transformer; this.action = action;
4625	>	}
4626	>	public final void compute() {
4627	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
4628	>	final Consumer<? super U> action;
4629	>	if ((transformer = this.transformer) != null &&
4630	>	(action = this.action) != null) {
4631	>	for (int i = baseIndex, f, h; batch > 0 &&
4632	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4633	>	addToPendingCount(1);
4634	>	new ForEachTransformedMappingTask<K,V,U>
4635	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4636	>	transformer, action).fork();
4637	>	}
4638	>	for (Node<K,V> p; (p = advance()) != null; ) {
4639	>	U u;
4640	>	if ((u = transformer.apply((K)p.key, p.val)) != null)
4641	>	action.accept(u);
4642	>	}
4643	>	propagateCompletion();
4644	>	}
4645		}
4646	<	public boolean isEmpty() {
4647	<	return ConcurrentHashMap.this.isEmpty();
4646	>	}
4647	>
4648	>	static final class SearchKeysTask<K,V,U>
4649	>	extends BulkTask<K,V,U> {
4650	>	final Function<? super K, ? extends U> searchFunction;
4651	>	final AtomicReference<U> result;
4652	>	SearchKeysTask
4653	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4654	>	Function<? super K, ? extends U> searchFunction,
4655	>	AtomicReference<U> result) {
4656	>	super(p, b, i, f, t);
4657	>	this.searchFunction = searchFunction; this.result = result;
4658	>	}
4659	>	public final U getRawResult() { return result.get(); }
4660	>	public final void compute() {
4661	>	final Function<? super K, ? extends U> searchFunction;
4662	>	final AtomicReference<U> result;
4663	>	if ((searchFunction = this.searchFunction) != null &&
4664	>	(result = this.result) != null) {
4665	>	for (int i = baseIndex, f, h; batch > 0 &&
4666	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4667	>	if (result.get() != null)
4668	>	return;
4669	>	addToPendingCount(1);
4670	>	new SearchKeysTask<K,V,U>
4671	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4672	>	searchFunction, result).fork();
4673	>	}
4674	>	while (result.get() == null) {
4675	>	U u;
4676	>	Node<K,V> p;
4677	>	if ((p = advance()) == null) {
4678	>	propagateCompletion();
4679	>	break;
4680	>	}
4681	>	if ((u = searchFunction.apply((K)p.key)) != null) {
4682	>	if (result.compareAndSet(null, u))
4683	>	quietlyCompleteRoot();
4684	>	break;
4685	>	}
4686	>	}
4687	>	}
4688		}
4689	<	public boolean contains(Object o) {
4690	<	return ConcurrentHashMap.this.containsValue(o);
4689	>	}
4690	>
4691	>	static final class SearchValuesTask<K,V,U>
4692	>	extends BulkTask<K,V,U> {
4693	>	final Function<? super V, ? extends U> searchFunction;
4694	>	final AtomicReference<U> result;
4695	>	SearchValuesTask
4696	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4697	>	Function<? super V, ? extends U> searchFunction,
4698	>	AtomicReference<U> result) {
4699	>	super(p, b, i, f, t);
4700	>	this.searchFunction = searchFunction; this.result = result;
4701	>	}
4702	>	public final U getRawResult() { return result.get(); }
4703	>	public final void compute() {
4704	>	final Function<? super V, ? extends U> searchFunction;
4705	>	final AtomicReference<U> result;
4706	>	if ((searchFunction = this.searchFunction) != null &&
4707	>	(result = this.result) != null) {
4708	>	for (int i = baseIndex, f, h; batch > 0 &&
4709	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4710	>	if (result.get() != null)
4711	>	return;
4712	>	addToPendingCount(1);
4713	>	new SearchValuesTask<K,V,U>
4714	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4715	>	searchFunction, result).fork();
4716	>	}
4717	>	while (result.get() == null) {
4718	>	U u;
4719	>	Node<K,V> p;
4720	>	if ((p = advance()) == null) {
4721	>	propagateCompletion();
4722	>	break;
4723	>	}
4724	>	if ((u = searchFunction.apply(p.val)) != null) {
4725	>	if (result.compareAndSet(null, u))
4726	>	quietlyCompleteRoot();
4727	>	break;
4728	>	}
4729	>	}
4730	>	}
4731		}
4732	<	public void clear() {
4733	<	ConcurrentHashMap.this.clear();
4732	>	}
4733	>
4734	>	static final class SearchEntriesTask<K,V,U>
4735	>	extends BulkTask<K,V,U> {
4736	>	final Function<Entry<K,V>, ? extends U> searchFunction;
4737	>	final AtomicReference<U> result;
4738	>	SearchEntriesTask
4739	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4740	>	Function<Entry<K,V>, ? extends U> searchFunction,
4741	>	AtomicReference<U> result) {
4742	>	super(p, b, i, f, t);
4743	>	this.searchFunction = searchFunction; this.result = result;
4744	>	}
4745	>	public final U getRawResult() { return result.get(); }
4746	>	public final void compute() {
4747	>	final Function<Entry<K,V>, ? extends U> searchFunction;
4748	>	final AtomicReference<U> result;
4749	>	if ((searchFunction = this.searchFunction) != null &&
4750	>	(result = this.result) != null) {
4751	>	for (int i = baseIndex, f, h; batch > 0 &&
4752	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4753	>	if (result.get() != null)
4754	>	return;
4755	>	addToPendingCount(1);
4756	>	new SearchEntriesTask<K,V,U>
4757	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4758	>	searchFunction, result).fork();
4759	>	}
4760	>	while (result.get() == null) {
4761	>	U u;
4762	>	Node<K,V> p;
4763	>	if ((p = advance()) == null) {
4764	>	propagateCompletion();
4765	>	break;
4766	>	}
4767	>	if ((u = searchFunction.apply(p)) != null) {
4768	>	if (result.compareAndSet(null, u))
4769	>	quietlyCompleteRoot();
4770	>	return;
4771	>	}
4772	>	}
4773	>	}
4774		}
4775		}
4776
4777	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
4778	<	public Iterator<Map.Entry<K,V>> iterator() {
4779	<	return new EntryIterator();
4777	>	static final class SearchMappingsTask<K,V,U>
4778	>	extends BulkTask<K,V,U> {
4779	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
4780	>	final AtomicReference<U> result;
4781	>	SearchMappingsTask
4782	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4783	>	BiFunction<? super K, ? super V, ? extends U> searchFunction,
4784	>	AtomicReference<U> result) {
4785	>	super(p, b, i, f, t);
4786	>	this.searchFunction = searchFunction; this.result = result;
4787	>	}
4788	>	public final U getRawResult() { return result.get(); }
4789	>	public final void compute() {
4790	>	final BiFunction<? super K, ? super V, ? extends U> searchFunction;
4791	>	final AtomicReference<U> result;
4792	>	if ((searchFunction = this.searchFunction) != null &&
4793	>	(result = this.result) != null) {
4794	>	for (int i = baseIndex, f, h; batch > 0 &&
4795	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4796	>	if (result.get() != null)
4797	>	return;
4798	>	addToPendingCount(1);
4799	>	new SearchMappingsTask<K,V,U>
4800	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4801	>	searchFunction, result).fork();
4802	>	}
4803	>	while (result.get() == null) {
4804	>	U u;
4805	>	Node<K,V> p;
4806	>	if ((p = advance()) == null) {
4807	>	propagateCompletion();
4808	>	break;
4809	>	}
4810	>	if ((u = searchFunction.apply((K)p.key, p.val)) != null) {
4811	>	if (result.compareAndSet(null, u))
4812	>	quietlyCompleteRoot();
4813	>	break;
4814	>	}
4815	>	}
4816	>	}
4817		}
4818	<	public boolean contains(Object o) {
4819	<	if (!(o instanceof Map.Entry))
4820	<	return false;
4821	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4822	<	V v = ConcurrentHashMap.this.get(e.getKey());
4823	<	return v != null && v.equals(e.getValue());
4818	>	}
4819	>
4820	>	static final class ReduceKeysTask<K,V>
4821	>	extends BulkTask<K,V,K> {
4822	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
4823	>	K result;
4824	>	ReduceKeysTask<K,V> rights, nextRight;
4825	>	ReduceKeysTask
4826	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4827	>	ReduceKeysTask<K,V> nextRight,
4828	>	BiFunction<? super K, ? super K, ? extends K> reducer) {
4829	>	super(p, b, i, f, t); this.nextRight = nextRight;
4830	>	this.reducer = reducer;
4831	>	}
4832	>	public final K getRawResult() { return result; }
4833	>	public final void compute() {
4834	>	final BiFunction<? super K, ? super K, ? extends K> reducer;
4835	>	if ((reducer = this.reducer) != null) {
4836	>	for (int i = baseIndex, f, h; batch > 0 &&
4837	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4838	>	addToPendingCount(1);
4839	>	(rights = new ReduceKeysTask<K,V>
4840	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4841	>	rights, reducer)).fork();
4842	>	}
4843	>	K r = null;
4844	>	for (Node<K,V> p; (p = advance()) != null; ) {
4845	>	K u = (K)p.key;
4846	>	r = (r == null) ? u : u == null ? r : reducer.apply(r, u);
4847	>	}
4848	>	result = r;
4849	>	CountedCompleter<?> c;
4850	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
4851	>	ReduceKeysTask<K,V>
4852	>	t = (ReduceKeysTask<K,V>)c,
4853	>	s = t.rights;
4854	>	while (s != null) {
4855	>	K tr, sr;
4856	>	if ((sr = s.result) != null)
4857	>	t.result = (((tr = t.result) == null) ? sr :
4858	>	reducer.apply(tr, sr));
4859	>	s = t.rights = s.nextRight;
4860	>	}
4861	>	}
4862	>	}
4863		}
4864	<	public boolean remove(Object o) {
4865	<	if (!(o instanceof Map.Entry))
4866	<	return false;
4867	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
4868	<	return ConcurrentHashMap.this.remove(e.getKey(), e.getValue());
4864	>	}
4865	>
4866	>	static final class ReduceValuesTask<K,V>
4867	>	extends BulkTask<K,V,V> {
4868	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
4869	>	V result;
4870	>	ReduceValuesTask<K,V> rights, nextRight;
4871	>	ReduceValuesTask
4872	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4873	>	ReduceValuesTask<K,V> nextRight,
4874	>	BiFunction<? super V, ? super V, ? extends V> reducer) {
4875	>	super(p, b, i, f, t); this.nextRight = nextRight;
4876	>	this.reducer = reducer;
4877	>	}
4878	>	public final V getRawResult() { return result; }
4879	>	public final void compute() {
4880	>	final BiFunction<? super V, ? super V, ? extends V> reducer;
4881	>	if ((reducer = this.reducer) != null) {
4882	>	for (int i = baseIndex, f, h; batch > 0 &&
4883	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4884	>	addToPendingCount(1);
4885	>	(rights = new ReduceValuesTask<K,V>
4886	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4887	>	rights, reducer)).fork();
4888	>	}
4889	>	V r = null;
4890	>	for (Node<K,V> p; (p = advance()) != null; ) {
4891	>	V v = p.val;
4892	>	r = (r == null) ? v : reducer.apply(r, v);
4893	>	}
4894	>	result = r;
4895	>	CountedCompleter<?> c;
4896	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
4897	>	ReduceValuesTask<K,V>
4898	>	t = (ReduceValuesTask<K,V>)c,
4899	>	s = t.rights;
4900	>	while (s != null) {
4901	>	V tr, sr;
4902	>	if ((sr = s.result) != null)
4903	>	t.result = (((tr = t.result) == null) ? sr :
4904	>	reducer.apply(tr, sr));
4905	>	s = t.rights = s.nextRight;
4906	>	}
4907	>	}
4908	>	}
4909		}
4910	<	public int size() {
4911	<	return ConcurrentHashMap.this.size();
4910	>	}
4911	>
4912	>	static final class ReduceEntriesTask<K,V>
4913	>	extends BulkTask<K,V,Map.Entry<K,V>> {
4914	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
4915	>	Map.Entry<K,V> result;
4916	>	ReduceEntriesTask<K,V> rights, nextRight;
4917	>	ReduceEntriesTask
4918	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4919	>	ReduceEntriesTask<K,V> nextRight,
4920	>	BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) {
4921	>	super(p, b, i, f, t); this.nextRight = nextRight;
4922	>	this.reducer = reducer;
4923	>	}
4924	>	public final Map.Entry<K,V> getRawResult() { return result; }
4925	>	public final void compute() {
4926	>	final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer;
4927	>	if ((reducer = this.reducer) != null) {
4928	>	for (int i = baseIndex, f, h; batch > 0 &&
4929	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4930	>	addToPendingCount(1);
4931	>	(rights = new ReduceEntriesTask<K,V>
4932	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4933	>	rights, reducer)).fork();
4934	>	}
4935	>	Map.Entry<K,V> r = null;
4936	>	for (Node<K,V> p; (p = advance()) != null; )
4937	>	r = (r == null) ? p : reducer.apply(r, p);
4938	>	result = r;
4939	>	CountedCompleter<?> c;
4940	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
4941	>	ReduceEntriesTask<K,V>
4942	>	t = (ReduceEntriesTask<K,V>)c,
4943	>	s = t.rights;
4944	>	while (s != null) {
4945	>	Map.Entry<K,V> tr, sr;
4946	>	if ((sr = s.result) != null)
4947	>	t.result = (((tr = t.result) == null) ? sr :
4948	>	reducer.apply(tr, sr));
4949	>	s = t.rights = s.nextRight;
4950	>	}
4951	>	}
4952	>	}
4953		}
4954	<	public boolean isEmpty() {
4955	<	return ConcurrentHashMap.this.isEmpty();
4954	>	}
4955	>
4956	>	static final class MapReduceKeysTask<K,V,U>
4957	>	extends BulkTask<K,V,U> {
4958	>	final Function<? super K, ? extends U> transformer;
4959	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
4960	>	U result;
4961	>	MapReduceKeysTask<K,V,U> rights, nextRight;
4962	>	MapReduceKeysTask
4963	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
4964	>	MapReduceKeysTask<K,V,U> nextRight,
4965	>	Function<? super K, ? extends U> transformer,
4966	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
4967	>	super(p, b, i, f, t); this.nextRight = nextRight;
4968	>	this.transformer = transformer;
4969	>	this.reducer = reducer;
4970	>	}
4971	>	public final U getRawResult() { return result; }
4972	>	public final void compute() {
4973	>	final Function<? super K, ? extends U> transformer;
4974	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
4975	>	if ((transformer = this.transformer) != null &&
4976	>	(reducer = this.reducer) != null) {
4977	>	for (int i = baseIndex, f, h; batch > 0 &&
4978	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
4979	>	addToPendingCount(1);
4980	>	(rights = new MapReduceKeysTask<K,V,U>
4981	>	(this, batch >>>= 1, baseLimit = h, f, tab,
4982	>	rights, transformer, reducer)).fork();
4983	>	}
4984	>	U r = null;
4985	>	for (Node<K,V> p; (p = advance()) != null; ) {
4986	>	U u;
4987	>	if ((u = transformer.apply((K)p.key)) != null)
4988	>	r = (r == null) ? u : reducer.apply(r, u);
4989	>	}
4990	>	result = r;
4991	>	CountedCompleter<?> c;
4992	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
4993	>	MapReduceKeysTask<K,V,U>
4994	>	t = (MapReduceKeysTask<K,V,U>)c,
4995	>	s = t.rights;
4996	>	while (s != null) {
4997	>	U tr, sr;
4998	>	if ((sr = s.result) != null)
4999	>	t.result = (((tr = t.result) == null) ? sr :
5000	>	reducer.apply(tr, sr));
5001	>	s = t.rights = s.nextRight;
5002	>	}
5003	>	}
5004	>	}
5005		}
5006	<	public void clear() {
5007	<	ConcurrentHashMap.this.clear();
5006	>	}
5007	>
5008	>	static final class MapReduceValuesTask<K,V,U>
5009	>	extends BulkTask<K,V,U> {
5010	>	final Function<? super V, ? extends U> transformer;
5011	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5012	>	U result;
5013	>	MapReduceValuesTask<K,V,U> rights, nextRight;
5014	>	MapReduceValuesTask
5015	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5016	>	MapReduceValuesTask<K,V,U> nextRight,
5017	>	Function<? super V, ? extends U> transformer,
5018	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5019	>	super(p, b, i, f, t); this.nextRight = nextRight;
5020	>	this.transformer = transformer;
5021	>	this.reducer = reducer;
5022	>	}
5023	>	public final U getRawResult() { return result; }
5024	>	public final void compute() {
5025	>	final Function<? super V, ? extends U> transformer;
5026	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5027	>	if ((transformer = this.transformer) != null &&
5028	>	(reducer = this.reducer) != null) {
5029	>	for (int i = baseIndex, f, h; batch > 0 &&
5030	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5031	>	addToPendingCount(1);
5032	>	(rights = new MapReduceValuesTask<K,V,U>
5033	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5034	>	rights, transformer, reducer)).fork();
5035	>	}
5036	>	U r = null;
5037	>	for (Node<K,V> p; (p = advance()) != null; ) {
5038	>	U u;
5039	>	if ((u = transformer.apply(p.val)) != null)
5040	>	r = (r == null) ? u : reducer.apply(r, u);
5041	>	}
5042	>	result = r;
5043	>	CountedCompleter<?> c;
5044	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5045	>	MapReduceValuesTask<K,V,U>
5046	>	t = (MapReduceValuesTask<K,V,U>)c,
5047	>	s = t.rights;
5048	>	while (s != null) {
5049	>	U tr, sr;
5050	>	if ((sr = s.result) != null)
5051	>	t.result = (((tr = t.result) == null) ? sr :
5052	>	reducer.apply(tr, sr));
5053	>	s = t.rights = s.nextRight;
5054	>	}
5055	>	}
5056	>	}
5057		}
5058		}
5059
5060	<	/* ---------------- Serialization Support -------------- */
5060	>	static final class MapReduceEntriesTask<K,V,U>
5061	>	extends BulkTask<K,V,U> {
5062	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5063	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5064	>	U result;
5065	>	MapReduceEntriesTask<K,V,U> rights, nextRight;
5066	>	MapReduceEntriesTask
5067	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5068	>	MapReduceEntriesTask<K,V,U> nextRight,
5069	>	Function<Map.Entry<K,V>, ? extends U> transformer,
5070	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5071	>	super(p, b, i, f, t); this.nextRight = nextRight;
5072	>	this.transformer = transformer;
5073	>	this.reducer = reducer;
5074	>	}
5075	>	public final U getRawResult() { return result; }
5076	>	public final void compute() {
5077	>	final Function<Map.Entry<K,V>, ? extends U> transformer;
5078	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5079	>	if ((transformer = this.transformer) != null &&
5080	>	(reducer = this.reducer) != null) {
5081	>	for (int i = baseIndex, f, h; batch > 0 &&
5082	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5083	>	addToPendingCount(1);
5084	>	(rights = new MapReduceEntriesTask<K,V,U>
5085	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5086	>	rights, transformer, reducer)).fork();
5087	>	}
5088	>	U r = null;
5089	>	for (Node<K,V> p; (p = advance()) != null; ) {
5090	>	U u;
5091	>	if ((u = transformer.apply(p)) != null)
5092	>	r = (r == null) ? u : reducer.apply(r, u);
5093	>	}
5094	>	result = r;
5095	>	CountedCompleter<?> c;
5096	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5097	>	MapReduceEntriesTask<K,V,U>
5098	>	t = (MapReduceEntriesTask<K,V,U>)c,
5099	>	s = t.rights;
5100	>	while (s != null) {
5101	>	U tr, sr;
5102	>	if ((sr = s.result) != null)
5103	>	t.result = (((tr = t.result) == null) ? sr :
5104	>	reducer.apply(tr, sr));
5105	>	s = t.rights = s.nextRight;
5106	>	}
5107	>	}
5108	>	}
5109	>	}
5110	>	}
5111
5112	<	/**
5113	<	* Saves the state of the <tt>ConcurrentHashMap</tt> instance to a
5114	<	* stream (i.e., serializes it).
5115	<	* @param s the stream
5116	<	* @serialData
5117	<	* the key (Object) and value (Object)
5118	<	* for each key-value mapping, followed by a null pair.
5119	<	* The key-value mappings are emitted in no particular order.
5120	<	*/
5121	<	private void writeObject(java.io.ObjectOutputStream s) throws IOException {
5122	<	// force all segments for serialization compatibility
5123	<	for (int k = 0; k < segments.length; ++k)
5124	<	ensureSegment(k);
5125	<	s.defaultWriteObject();
5126	<
5127	<	final Segment<K,V>[] segments = this.segments;
5128	<	for (int k = 0; k < segments.length; ++k) {
5129	<	Segment<K,V> seg = segmentAt(segments, k);
5130	<	seg.lock();
5131	<	try {
5132	<	HashEntry<K,V>[] tab = seg.table;
5133	<	for (int i = 0; i < tab.length; ++i) {
5134	<	HashEntry<K,V> e;
5135	<	for (e = entryAt(tab, i); e != null; e = e.next) {
5136	<	s.writeObject(e.key);
5137	<	s.writeObject(e.value);
5112	>	static final class MapReduceMappingsTask<K,V,U>
5113	>	extends BulkTask<K,V,U> {
5114	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5115	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5116	>	U result;
5117	>	MapReduceMappingsTask<K,V,U> rights, nextRight;
5118	>	MapReduceMappingsTask
5119	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5120	>	MapReduceMappingsTask<K,V,U> nextRight,
5121	>	BiFunction<? super K, ? super V, ? extends U> transformer,
5122	>	BiFunction<? super U, ? super U, ? extends U> reducer) {
5123	>	super(p, b, i, f, t); this.nextRight = nextRight;
5124	>	this.transformer = transformer;
5125	>	this.reducer = reducer;
5126	>	}
5127	>	public final U getRawResult() { return result; }
5128	>	public final void compute() {
5129	>	final BiFunction<? super K, ? super V, ? extends U> transformer;
5130	>	final BiFunction<? super U, ? super U, ? extends U> reducer;
5131	>	if ((transformer = this.transformer) != null &&
5132	>	(reducer = this.reducer) != null) {
5133	>	for (int i = baseIndex, f, h; batch > 0 &&
5134	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5135	>	addToPendingCount(1);
5136	>	(rights = new MapReduceMappingsTask<K,V,U>
5137	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5138	>	rights, transformer, reducer)).fork();
5139	>	}
5140	>	U r = null;
5141	>	for (Node<K,V> p; (p = advance()) != null; ) {
5142	>	U u;
5143	>	if ((u = transformer.apply((K)p.key, p.val)) != null)
5144	>	r = (r == null) ? u : reducer.apply(r, u);
5145	>	}
5146	>	result = r;
5147	>	CountedCompleter<?> c;
5148	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5149	>	MapReduceMappingsTask<K,V,U>
5150	>	t = (MapReduceMappingsTask<K,V,U>)c,
5151	>	s = t.rights;
5152	>	while (s != null) {
5153	>	U tr, sr;
5154	>	if ((sr = s.result) != null)
5155	>	t.result = (((tr = t.result) == null) ? sr :
5156	>	reducer.apply(tr, sr));
5157	>	s = t.rights = s.nextRight;
5158		}
5159		}
1427	–	} finally {
1428	–	seg.unlock();
5160		}
5161		}
1431	–	s.writeObject(null);
1432	–	s.writeObject(null);
5162		}
5163
5164	<	/**
5165	<	* Reconstitutes the <tt>ConcurrentHashMap</tt> instance from a
5166	<	* stream (i.e., deserializes it).
5167	<	* @param s the stream
5168	<	*/
5169	<	@SuppressWarnings("unchecked")
5170	<	private void readObject(java.io.ObjectInputStream s)
5171	<	throws IOException, ClassNotFoundException {
5172	<	s.defaultReadObject();
5164	>	static final class MapReduceKeysToDoubleTask<K,V>
5165	>	extends BulkTask<K,V,Double> {
5166	>	final ToDoubleFunction<? super K> transformer;
5167	>	final DoubleBinaryOperator reducer;
5168	>	final double basis;
5169	>	double result;
5170	>	MapReduceKeysToDoubleTask<K,V> rights, nextRight;
5171	>	MapReduceKeysToDoubleTask
5172	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5173	>	MapReduceKeysToDoubleTask<K,V> nextRight,
5174	>	ToDoubleFunction<? super K> transformer,
5175	>	double basis,
5176	>	DoubleBinaryOperator reducer) {
5177	>	super(p, b, i, f, t); this.nextRight = nextRight;
5178	>	this.transformer = transformer;
5179	>	this.basis = basis; this.reducer = reducer;
5180	>	}
5181	>	public final Double getRawResult() { return result; }
5182	>	public final void compute() {
5183	>	final ToDoubleFunction<? super K> transformer;
5184	>	final DoubleBinaryOperator reducer;
5185	>	if ((transformer = this.transformer) != null &&
5186	>	(reducer = this.reducer) != null) {
5187	>	double r = this.basis;
5188	>	for (int i = baseIndex, f, h; batch > 0 &&
5189	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5190	>	addToPendingCount(1);
5191	>	(rights = new MapReduceKeysToDoubleTask<K,V>
5192	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5193	>	rights, transformer, r, reducer)).fork();
5194	>	}
5195	>	for (Node<K,V> p; (p = advance()) != null; )
5196	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble((K)p.key));
5197	>	result = r;
5198	>	CountedCompleter<?> c;
5199	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5200	>	MapReduceKeysToDoubleTask<K,V>
5201	>	t = (MapReduceKeysToDoubleTask<K,V>)c,
5202	>	s = t.rights;
5203	>	while (s != null) {
5204	>	t.result = reducer.applyAsDouble(t.result, s.result);
5205	>	s = t.rights = s.nextRight;
5206	>	}
5207	>	}
5208	>	}
5209	>	}
5210	>	}
5211
5212	<	// Re-initialize segments to be minimally sized, and let grow.
5213	<	int cap = MIN_SEGMENT_TABLE_CAPACITY;
5214	<	final Segment<K,V>[] segments = this.segments;
5215	<	for (int k = 0; k < segments.length; ++k) {
5216	<	Segment<K,V> seg = segments[k];
5217	<	if (seg != null) {
5218	<	seg.threshold = (int)(cap * seg.loadFactor);
5219	<	seg.table = (HashEntry<K,V>[]) new HashEntry[cap];
5212	>	static final class MapReduceValuesToDoubleTask<K,V>
5213	>	extends BulkTask<K,V,Double> {
5214	>	final ToDoubleFunction<? super V> transformer;
5215	>	final DoubleBinaryOperator reducer;
5216	>	final double basis;
5217	>	double result;
5218	>	MapReduceValuesToDoubleTask<K,V> rights, nextRight;
5219	>	MapReduceValuesToDoubleTask
5220	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5221	>	MapReduceValuesToDoubleTask<K,V> nextRight,
5222	>	ToDoubleFunction<? super V> transformer,
5223	>	double basis,
5224	>	DoubleBinaryOperator reducer) {
5225	>	super(p, b, i, f, t); this.nextRight = nextRight;
5226	>	this.transformer = transformer;
5227	>	this.basis = basis; this.reducer = reducer;
5228	>	}
5229	>	public final Double getRawResult() { return result; }
5230	>	public final void compute() {
5231	>	final ToDoubleFunction<? super V> transformer;
5232	>	final DoubleBinaryOperator reducer;
5233	>	if ((transformer = this.transformer) != null &&
5234	>	(reducer = this.reducer) != null) {
5235	>	double r = this.basis;
5236	>	for (int i = baseIndex, f, h; batch > 0 &&
5237	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5238	>	addToPendingCount(1);
5239	>	(rights = new MapReduceValuesToDoubleTask<K,V>
5240	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5241	>	rights, transformer, r, reducer)).fork();
5242	>	}
5243	>	for (Node<K,V> p; (p = advance()) != null; )
5244	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val));
5245	>	result = r;
5246	>	CountedCompleter<?> c;
5247	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5248	>	MapReduceValuesToDoubleTask<K,V>
5249	>	t = (MapReduceValuesToDoubleTask<K,V>)c,
5250	>	s = t.rights;
5251	>	while (s != null) {
5252	>	t.result = reducer.applyAsDouble(t.result, s.result);
5253	>	s = t.rights = s.nextRight;
5254	>	}
5255	>	}
5256		}
5257		}
5258	+	}
5259
5260	<	// Read the keys and values, and put the mappings in the table
5261	<	for (;;) {
5262	<	K key = (K) s.readObject();
5263	<	V value = (V) s.readObject();
5264	<	if (key == null)
5265	<	break;
5266	<	put(key, value);
5260	>	static final class MapReduceEntriesToDoubleTask<K,V>
5261	>	extends BulkTask<K,V,Double> {
5262	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5263	>	final DoubleBinaryOperator reducer;
5264	>	final double basis;
5265	>	double result;
5266	>	MapReduceEntriesToDoubleTask<K,V> rights, nextRight;
5267	>	MapReduceEntriesToDoubleTask
5268	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5269	>	MapReduceEntriesToDoubleTask<K,V> nextRight,
5270	>	ToDoubleFunction<Map.Entry<K,V>> transformer,
5271	>	double basis,
5272	>	DoubleBinaryOperator reducer) {
5273	>	super(p, b, i, f, t); this.nextRight = nextRight;
5274	>	this.transformer = transformer;
5275	>	this.basis = basis; this.reducer = reducer;
5276	>	}
5277	>	public final Double getRawResult() { return result; }
5278	>	public final void compute() {
5279	>	final ToDoubleFunction<Map.Entry<K,V>> transformer;
5280	>	final DoubleBinaryOperator reducer;
5281	>	if ((transformer = this.transformer) != null &&
5282	>	(reducer = this.reducer) != null) {
5283	>	double r = this.basis;
5284	>	for (int i = baseIndex, f, h; batch > 0 &&
5285	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5286	>	addToPendingCount(1);
5287	>	(rights = new MapReduceEntriesToDoubleTask<K,V>
5288	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5289	>	rights, transformer, r, reducer)).fork();
5290	>	}
5291	>	for (Node<K,V> p; (p = advance()) != null; )
5292	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble(p));
5293	>	result = r;
5294	>	CountedCompleter<?> c;
5295	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5296	>	MapReduceEntriesToDoubleTask<K,V>
5297	>	t = (MapReduceEntriesToDoubleTask<K,V>)c,
5298	>	s = t.rights;
5299	>	while (s != null) {
5300	>	t.result = reducer.applyAsDouble(t.result, s.result);
5301	>	s = t.rights = s.nextRight;
5302	>	}
5303	>	}
5304	>	}
5305	>	}
5306	>	}
5307	>
5308	>	static final class MapReduceMappingsToDoubleTask<K,V>
5309	>	extends BulkTask<K,V,Double> {
5310	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5311	>	final DoubleBinaryOperator reducer;
5312	>	final double basis;
5313	>	double result;
5314	>	MapReduceMappingsToDoubleTask<K,V> rights, nextRight;
5315	>	MapReduceMappingsToDoubleTask
5316	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5317	>	MapReduceMappingsToDoubleTask<K,V> nextRight,
5318	>	ToDoubleBiFunction<? super K, ? super V> transformer,
5319	>	double basis,
5320	>	DoubleBinaryOperator reducer) {
5321	>	super(p, b, i, f, t); this.nextRight = nextRight;
5322	>	this.transformer = transformer;
5323	>	this.basis = basis; this.reducer = reducer;
5324	>	}
5325	>	public final Double getRawResult() { return result; }
5326	>	public final void compute() {
5327	>	final ToDoubleBiFunction<? super K, ? super V> transformer;
5328	>	final DoubleBinaryOperator reducer;
5329	>	if ((transformer = this.transformer) != null &&
5330	>	(reducer = this.reducer) != null) {
5331	>	double r = this.basis;
5332	>	for (int i = baseIndex, f, h; batch > 0 &&
5333	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5334	>	addToPendingCount(1);
5335	>	(rights = new MapReduceMappingsToDoubleTask<K,V>
5336	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5337	>	rights, transformer, r, reducer)).fork();
5338	>	}
5339	>	for (Node<K,V> p; (p = advance()) != null; )
5340	>	r = reducer.applyAsDouble(r, transformer.applyAsDouble((K)p.key, p.val));
5341	>	result = r;
5342	>	CountedCompleter<?> c;
5343	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5344	>	MapReduceMappingsToDoubleTask<K,V>
5345	>	t = (MapReduceMappingsToDoubleTask<K,V>)c,
5346	>	s = t.rights;
5347	>	while (s != null) {
5348	>	t.result = reducer.applyAsDouble(t.result, s.result);
5349	>	s = t.rights = s.nextRight;
5350	>	}
5351	>	}
5352	>	}
5353	>	}
5354	>	}
5355	>
5356	>	static final class MapReduceKeysToLongTask<K,V>
5357	>	extends BulkTask<K,V,Long> {
5358	>	final ToLongFunction<? super K> transformer;
5359	>	final LongBinaryOperator reducer;
5360	>	final long basis;
5361	>	long result;
5362	>	MapReduceKeysToLongTask<K,V> rights, nextRight;
5363	>	MapReduceKeysToLongTask
5364	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5365	>	MapReduceKeysToLongTask<K,V> nextRight,
5366	>	ToLongFunction<? super K> transformer,
5367	>	long basis,
5368	>	LongBinaryOperator reducer) {
5369	>	super(p, b, i, f, t); this.nextRight = nextRight;
5370	>	this.transformer = transformer;
5371	>	this.basis = basis; this.reducer = reducer;
5372	>	}
5373	>	public final Long getRawResult() { return result; }
5374	>	public final void compute() {
5375	>	final ToLongFunction<? super K> transformer;
5376	>	final LongBinaryOperator reducer;
5377	>	if ((transformer = this.transformer) != null &&
5378	>	(reducer = this.reducer) != null) {
5379	>	long r = this.basis;
5380	>	for (int i = baseIndex, f, h; batch > 0 &&
5381	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5382	>	addToPendingCount(1);
5383	>	(rights = new MapReduceKeysToLongTask<K,V>
5384	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5385	>	rights, transformer, r, reducer)).fork();
5386	>	}
5387	>	for (Node<K,V> p; (p = advance()) != null; )
5388	>	r = reducer.applyAsLong(r, transformer.applyAsLong((K)p.key));
5389	>	result = r;
5390	>	CountedCompleter<?> c;
5391	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5392	>	MapReduceKeysToLongTask<K,V>
5393	>	t = (MapReduceKeysToLongTask<K,V>)c,
5394	>	s = t.rights;
5395	>	while (s != null) {
5396	>	t.result = reducer.applyAsLong(t.result, s.result);
5397	>	s = t.rights = s.nextRight;
5398	>	}
5399	>	}
5400	>	}
5401	>	}
5402	>	}
5403	>
5404	>	static final class MapReduceValuesToLongTask<K,V>
5405	>	extends BulkTask<K,V,Long> {
5406	>	final ToLongFunction<? super V> transformer;
5407	>	final LongBinaryOperator reducer;
5408	>	final long basis;
5409	>	long result;
5410	>	MapReduceValuesToLongTask<K,V> rights, nextRight;
5411	>	MapReduceValuesToLongTask
5412	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5413	>	MapReduceValuesToLongTask<K,V> nextRight,
5414	>	ToLongFunction<? super V> transformer,
5415	>	long basis,
5416	>	LongBinaryOperator reducer) {
5417	>	super(p, b, i, f, t); this.nextRight = nextRight;
5418	>	this.transformer = transformer;
5419	>	this.basis = basis; this.reducer = reducer;
5420	>	}
5421	>	public final Long getRawResult() { return result; }
5422	>	public final void compute() {
5423	>	final ToLongFunction<? super V> transformer;
5424	>	final LongBinaryOperator reducer;
5425	>	if ((transformer = this.transformer) != null &&
5426	>	(reducer = this.reducer) != null) {
5427	>	long r = this.basis;
5428	>	for (int i = baseIndex, f, h; batch > 0 &&
5429	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5430	>	addToPendingCount(1);
5431	>	(rights = new MapReduceValuesToLongTask<K,V>
5432	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5433	>	rights, transformer, r, reducer)).fork();
5434	>	}
5435	>	for (Node<K,V> p; (p = advance()) != null; )
5436	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p.val));
5437	>	result = r;
5438	>	CountedCompleter<?> c;
5439	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5440	>	MapReduceValuesToLongTask<K,V>
5441	>	t = (MapReduceValuesToLongTask<K,V>)c,
5442	>	s = t.rights;
5443	>	while (s != null) {
5444	>	t.result = reducer.applyAsLong(t.result, s.result);
5445	>	s = t.rights = s.nextRight;
5446	>	}
5447	>	}
5448	>	}
5449	>	}
5450	>	}
5451	>
5452	>	static final class MapReduceEntriesToLongTask<K,V>
5453	>	extends BulkTask<K,V,Long> {
5454	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5455	>	final LongBinaryOperator reducer;
5456	>	final long basis;
5457	>	long result;
5458	>	MapReduceEntriesToLongTask<K,V> rights, nextRight;
5459	>	MapReduceEntriesToLongTask
5460	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5461	>	MapReduceEntriesToLongTask<K,V> nextRight,
5462	>	ToLongFunction<Map.Entry<K,V>> transformer,
5463	>	long basis,
5464	>	LongBinaryOperator reducer) {
5465	>	super(p, b, i, f, t); this.nextRight = nextRight;
5466	>	this.transformer = transformer;
5467	>	this.basis = basis; this.reducer = reducer;
5468	>	}
5469	>	public final Long getRawResult() { return result; }
5470	>	public final void compute() {
5471	>	final ToLongFunction<Map.Entry<K,V>> transformer;
5472	>	final LongBinaryOperator reducer;
5473	>	if ((transformer = this.transformer) != null &&
5474	>	(reducer = this.reducer) != null) {
5475	>	long r = this.basis;
5476	>	for (int i = baseIndex, f, h; batch > 0 &&
5477	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5478	>	addToPendingCount(1);
5479	>	(rights = new MapReduceEntriesToLongTask<K,V>
5480	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5481	>	rights, transformer, r, reducer)).fork();
5482	>	}
5483	>	for (Node<K,V> p; (p = advance()) != null; )
5484	>	r = reducer.applyAsLong(r, transformer.applyAsLong(p));
5485	>	result = r;
5486	>	CountedCompleter<?> c;
5487	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5488	>	MapReduceEntriesToLongTask<K,V>
5489	>	t = (MapReduceEntriesToLongTask<K,V>)c,
5490	>	s = t.rights;
5491	>	while (s != null) {
5492	>	t.result = reducer.applyAsLong(t.result, s.result);
5493	>	s = t.rights = s.nextRight;
5494	>	}
5495	>	}
5496	>	}
5497	>	}
5498	>	}
5499	>
5500	>	static final class MapReduceMappingsToLongTask<K,V>
5501	>	extends BulkTask<K,V,Long> {
5502	>	final ToLongBiFunction<? super K, ? super V> transformer;
5503	>	final LongBinaryOperator reducer;
5504	>	final long basis;
5505	>	long result;
5506	>	MapReduceMappingsToLongTask<K,V> rights, nextRight;
5507	>	MapReduceMappingsToLongTask
5508	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5509	>	MapReduceMappingsToLongTask<K,V> nextRight,
5510	>	ToLongBiFunction<? super K, ? super V> transformer,
5511	>	long basis,
5512	>	LongBinaryOperator reducer) {
5513	>	super(p, b, i, f, t); this.nextRight = nextRight;
5514	>	this.transformer = transformer;
5515	>	this.basis = basis; this.reducer = reducer;
5516	>	}
5517	>	public final Long getRawResult() { return result; }
5518	>	public final void compute() {
5519	>	final ToLongBiFunction<? super K, ? super V> transformer;
5520	>	final LongBinaryOperator reducer;
5521	>	if ((transformer = this.transformer) != null &&
5522	>	(reducer = this.reducer) != null) {
5523	>	long r = this.basis;
5524	>	for (int i = baseIndex, f, h; batch > 0 &&
5525	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5526	>	addToPendingCount(1);
5527	>	(rights = new MapReduceMappingsToLongTask<K,V>
5528	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5529	>	rights, transformer, r, reducer)).fork();
5530	>	}
5531	>	for (Node<K,V> p; (p = advance()) != null; )
5532	>	r = reducer.applyAsLong(r, transformer.applyAsLong((K)p.key, p.val));
5533	>	result = r;
5534	>	CountedCompleter<?> c;
5535	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5536	>	MapReduceMappingsToLongTask<K,V>
5537	>	t = (MapReduceMappingsToLongTask<K,V>)c,
5538	>	s = t.rights;
5539	>	while (s != null) {
5540	>	t.result = reducer.applyAsLong(t.result, s.result);
5541	>	s = t.rights = s.nextRight;
5542	>	}
5543	>	}
5544	>	}
5545	>	}
5546	>	}
5547	>
5548	>	static final class MapReduceKeysToIntTask<K,V>
5549	>	extends BulkTask<K,V,Integer> {
5550	>	final ToIntFunction<? super K> transformer;
5551	>	final IntBinaryOperator reducer;
5552	>	final int basis;
5553	>	int result;
5554	>	MapReduceKeysToIntTask<K,V> rights, nextRight;
5555	>	MapReduceKeysToIntTask
5556	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5557	>	MapReduceKeysToIntTask<K,V> nextRight,
5558	>	ToIntFunction<? super K> transformer,
5559	>	int basis,
5560	>	IntBinaryOperator reducer) {
5561	>	super(p, b, i, f, t); this.nextRight = nextRight;
5562	>	this.transformer = transformer;
5563	>	this.basis = basis; this.reducer = reducer;
5564	>	}
5565	>	public final Integer getRawResult() { return result; }
5566	>	public final void compute() {
5567	>	final ToIntFunction<? super K> transformer;
5568	>	final IntBinaryOperator reducer;
5569	>	if ((transformer = this.transformer) != null &&
5570	>	(reducer = this.reducer) != null) {
5571	>	int r = this.basis;
5572	>	for (int i = baseIndex, f, h; batch > 0 &&
5573	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5574	>	addToPendingCount(1);
5575	>	(rights = new MapReduceKeysToIntTask<K,V>
5576	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5577	>	rights, transformer, r, reducer)).fork();
5578	>	}
5579	>	for (Node<K,V> p; (p = advance()) != null; )
5580	>	r = reducer.applyAsInt(r, transformer.applyAsInt((K)p.key));
5581	>	result = r;
5582	>	CountedCompleter<?> c;
5583	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5584	>	MapReduceKeysToIntTask<K,V>
5585	>	t = (MapReduceKeysToIntTask<K,V>)c,
5586	>	s = t.rights;
5587	>	while (s != null) {
5588	>	t.result = reducer.applyAsInt(t.result, s.result);
5589	>	s = t.rights = s.nextRight;
5590	>	}
5591	>	}
5592	>	}
5593	>	}
5594	>	}
5595	>
5596	>	static final class MapReduceValuesToIntTask<K,V>
5597	>	extends BulkTask<K,V,Integer> {
5598	>	final ToIntFunction<? super V> transformer;
5599	>	final IntBinaryOperator reducer;
5600	>	final int basis;
5601	>	int result;
5602	>	MapReduceValuesToIntTask<K,V> rights, nextRight;
5603	>	MapReduceValuesToIntTask
5604	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5605	>	MapReduceValuesToIntTask<K,V> nextRight,
5606	>	ToIntFunction<? super V> transformer,
5607	>	int basis,
5608	>	IntBinaryOperator reducer) {
5609	>	super(p, b, i, f, t); this.nextRight = nextRight;
5610	>	this.transformer = transformer;
5611	>	this.basis = basis; this.reducer = reducer;
5612	>	}
5613	>	public final Integer getRawResult() { return result; }
5614	>	public final void compute() {
5615	>	final ToIntFunction<? super V> transformer;
5616	>	final IntBinaryOperator reducer;
5617	>	if ((transformer = this.transformer) != null &&
5618	>	(reducer = this.reducer) != null) {
5619	>	int r = this.basis;
5620	>	for (int i = baseIndex, f, h; batch > 0 &&
5621	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5622	>	addToPendingCount(1);
5623	>	(rights = new MapReduceValuesToIntTask<K,V>
5624	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5625	>	rights, transformer, r, reducer)).fork();
5626	>	}
5627	>	for (Node<K,V> p; (p = advance()) != null; )
5628	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p.val));
5629	>	result = r;
5630	>	CountedCompleter<?> c;
5631	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5632	>	MapReduceValuesToIntTask<K,V>
5633	>	t = (MapReduceValuesToIntTask<K,V>)c,
5634	>	s = t.rights;
5635	>	while (s != null) {
5636	>	t.result = reducer.applyAsInt(t.result, s.result);
5637	>	s = t.rights = s.nextRight;
5638	>	}
5639	>	}
5640	>	}
5641	>	}
5642	>	}
5643	>
5644	>	static final class MapReduceEntriesToIntTask<K,V>
5645	>	extends BulkTask<K,V,Integer> {
5646	>	final ToIntFunction<Map.Entry<K,V>> transformer;
5647	>	final IntBinaryOperator reducer;
5648	>	final int basis;
5649	>	int result;
5650	>	MapReduceEntriesToIntTask<K,V> rights, nextRight;
5651	>	MapReduceEntriesToIntTask
5652	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5653	>	MapReduceEntriesToIntTask<K,V> nextRight,
5654	>	ToIntFunction<Map.Entry<K,V>> transformer,
5655	>	int basis,
5656	>	IntBinaryOperator reducer) {
5657	>	super(p, b, i, f, t); this.nextRight = nextRight;
5658	>	this.transformer = transformer;
5659	>	this.basis = basis; this.reducer = reducer;
5660	>	}
5661	>	public final Integer getRawResult() { return result; }
5662	>	public final void compute() {
5663	>	final ToIntFunction<Map.Entry<K,V>> transformer;
5664	>	final IntBinaryOperator reducer;
5665	>	if ((transformer = this.transformer) != null &&
5666	>	(reducer = this.reducer) != null) {
5667	>	int r = this.basis;
5668	>	for (int i = baseIndex, f, h; batch > 0 &&
5669	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5670	>	addToPendingCount(1);
5671	>	(rights = new MapReduceEntriesToIntTask<K,V>
5672	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5673	>	rights, transformer, r, reducer)).fork();
5674	>	}
5675	>	for (Node<K,V> p; (p = advance()) != null; )
5676	>	r = reducer.applyAsInt(r, transformer.applyAsInt(p));
5677	>	result = r;
5678	>	CountedCompleter<?> c;
5679	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5680	>	MapReduceEntriesToIntTask<K,V>
5681	>	t = (MapReduceEntriesToIntTask<K,V>)c,
5682	>	s = t.rights;
5683	>	while (s != null) {
5684	>	t.result = reducer.applyAsInt(t.result, s.result);
5685	>	s = t.rights = s.nextRight;
5686	>	}
5687	>	}
5688	>	}
5689	>	}
5690	>	}
5691	>
5692	>	static final class MapReduceMappingsToIntTask<K,V>
5693	>	extends BulkTask<K,V,Integer> {
5694	>	final ToIntBiFunction<? super K, ? super V> transformer;
5695	>	final IntBinaryOperator reducer;
5696	>	final int basis;
5697	>	int result;
5698	>	MapReduceMappingsToIntTask<K,V> rights, nextRight;
5699	>	MapReduceMappingsToIntTask
5700	>	(BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t,
5701	>	MapReduceMappingsToIntTask<K,V> nextRight,
5702	>	ToIntBiFunction<? super K, ? super V> transformer,
5703	>	int basis,
5704	>	IntBinaryOperator reducer) {
5705	>	super(p, b, i, f, t); this.nextRight = nextRight;
5706	>	this.transformer = transformer;
5707	>	this.basis = basis; this.reducer = reducer;
5708	>	}
5709	>	public final Integer getRawResult() { return result; }
5710	>	public final void compute() {
5711	>	final ToIntBiFunction<? super K, ? super V> transformer;
5712	>	final IntBinaryOperator reducer;
5713	>	if ((transformer = this.transformer) != null &&
5714	>	(reducer = this.reducer) != null) {
5715	>	int r = this.basis;
5716	>	for (int i = baseIndex, f, h; batch > 0 &&
5717	>	(h = ((f = baseLimit) + i) >>> 1) > i;) {
5718	>	addToPendingCount(1);
5719	>	(rights = new MapReduceMappingsToIntTask<K,V>
5720	>	(this, batch >>>= 1, baseLimit = h, f, tab,
5721	>	rights, transformer, r, reducer)).fork();
5722	>	}
5723	>	for (Node<K,V> p; (p = advance()) != null; )
5724	>	r = reducer.applyAsInt(r, transformer.applyAsInt((K)p.key, p.val));
5725	>	result = r;
5726	>	CountedCompleter<?> c;
5727	>	for (c = firstComplete(); c != null; c = c.nextComplete()) {
5728	>	MapReduceMappingsToIntTask<K,V>
5729	>	t = (MapReduceMappingsToIntTask<K,V>)c,
5730	>	s = t.rights;
5731	>	while (s != null) {
5732	>	t.result = reducer.applyAsInt(t.result, s.result);
5733	>	s = t.rights = s.nextRight;
5734	>	}
5735	>	}
5736	>	}
5737		}
5738		}
5739
5740		// Unsafe mechanics
5741	<	private static final sun.misc.Unsafe UNSAFE;
5742	<	private static final long SBASE;
5743	<	private static final int SSHIFT;
5744	<	private static final long TBASE;
5745	<	private static final int TSHIFT;
5741	>	private static final sun.misc.Unsafe U;
5742	>	private static final long SIZECTL;
5743	>	private static final long TRANSFERINDEX;
5744	>	private static final long TRANSFERORIGIN;
5745	>	private static final long BASECOUNT;
5746	>	private static final long CELLSBUSY;
5747	>	private static final long CELLVALUE;
5748	>	private static final long ABASE;
5749	>	private static final int ASHIFT;
5750
5751		static {
1474	–	int ss, ts;
5752		try {
5753	<	UNSAFE = sun.misc.Unsafe.getUnsafe();
5754	<	Class tc = HashEntry[].class;
5755	<	Class sc = Segment[].class;
5756	<	TBASE = UNSAFE.arrayBaseOffset(tc);
5757	<	SBASE = UNSAFE.arrayBaseOffset(sc);
5758	<	ts = UNSAFE.arrayIndexScale(tc);
5759	<	ss = UNSAFE.arrayIndexScale(sc);
5753	>	U = sun.misc.Unsafe.getUnsafe();
5754	>	Class<?> k = ConcurrentHashMap.class;
5755	>	SIZECTL = U.objectFieldOffset
5756	>	(k.getDeclaredField("sizeCtl"));
5757	>	TRANSFERINDEX = U.objectFieldOffset
5758	>	(k.getDeclaredField("transferIndex"));
5759	>	TRANSFERORIGIN = U.objectFieldOffset
5760	>	(k.getDeclaredField("transferOrigin"));
5761	>	BASECOUNT = U.objectFieldOffset
5762	>	(k.getDeclaredField("baseCount"));
5763	>	CELLSBUSY = U.objectFieldOffset
5764	>	(k.getDeclaredField("cellsBusy"));
5765	>	Class<?> ck = Cell.class;
5766	>	CELLVALUE = U.objectFieldOffset
5767	>	(ck.getDeclaredField("value"));
5768	>	Class<?> sc = Node[].class;
5769	>	ABASE = U.arrayBaseOffset(sc);
5770	>	int scale = U.arrayIndexScale(sc);
5771	>	if ((scale & (scale - 1)) != 0)
5772	>	throw new Error("data type scale not a power of two");
5773	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
5774		} catch (Exception e) {
5775		throw new Error(e);
5776		}
1486	–	if ((ss & (ss-1)) != 0 || (ts & (ts-1)) != 0)
1487	–	throw new Error("data type scale not a power of two");
1488	–	SSHIFT = 31 - Integer.numberOfLeadingZeros(ss);
1489	–	TSHIFT = 31 - Integer.numberOfLeadingZeros(ts);
5777		}
1491	–
5778		}

Diff Legend

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