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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.3 by jsr166, Tue Aug 30 07:18:46 2011 UTC vs.
Revision 1.42 by jsr166, Wed Jul 4 20:10:00 2012 UTC

#	Line 6 | Line 6
6
7		package jsr166e;
8		import jsr166e.LongAdder;
9	+	import java.util.Arrays;
10		import java.util.Map;
11		import java.util.Set;
12		import java.util.Collection;
#	Line 19 | Line 20 | import java.util.Enumeration;
20		import java.util.ConcurrentModificationException;
21		import java.util.NoSuchElementException;
22		import java.util.concurrent.ConcurrentMap;
23	+	import java.util.concurrent.ThreadLocalRandom;
24	+	import java.util.concurrent.locks.LockSupport;
25	+	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
26		import java.io.Serializable;
27
28		/**
#	Line 49 | Line 53 | import java.io.Serializable;
53		* are typically useful only when a map is not undergoing concurrent
54		* updates in other threads.  Otherwise the results of these methods
55		* reflect transient states that may be adequate for monitoring
56	<	* purposes, but not for program control.
56	>	* or estimation purposes, but not for program control.
57		*
58	<	* <p> Resizing this or any other kind of hash table is a relatively
59	<	* slow operation, so, when possible, it is a good idea to provide
60	<	* estimates of expected table sizes in constructors. Also, for
61	<	* compatability with previous versions of this class, constructors
62	<	* may optionally specify an expected {@code concurrencyLevel} as an
63	<	* additional hint for internal sizing.
58	>	* <p> The table is dynamically expanded when there are too many
59	>	* collisions (i.e., keys that have distinct hash codes but fall into
60	>	* the same slot modulo the table size), with the expected average
61	>	* effect of maintaining roughly two bins per mapping (corresponding
62	>	* to a 0.75 load factor threshold for resizing). There may be much
63	>	* variance around this average as mappings are added and removed, but
64	>	* overall, this maintains a commonly accepted time/space tradeoff for
65	>	* hash tables.  However, resizing this or any other kind of hash
66	>	* table may be a relatively slow operation. When possible, it is a
67	>	* good idea to provide a size estimate as an optional {@code
68	>	* initialCapacity} constructor argument. An additional optional
69	>	* {@code loadFactor} constructor argument provides a further means of
70	>	* customizing initial table capacity by specifying the table density
71	>	* to be used in calculating the amount of space to allocate for the
72	>	* given number of elements.  Also, for compatibility with previous
73	>	* versions of this class, constructors may optionally specify an
74	>	* expected {@code concurrencyLevel} as an additional hint for
75	>	* internal sizing.  Note that using many keys with exactly the same
76	>	* {@code hashCode()} is a sure way to slow down performance of any
77	>	* hash table.
78		*
79		* <p>This class and its views and iterators implement all of the
80		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
#	Line 82 | Line 100 | public class ConcurrentHashMapV8<K, V>
100		private static final long serialVersionUID = 7249069246763182397L;
101
102		/**
103	<	* A function computing a mapping from the given key to a value,
104	<	*  or <code>null</code> if there is no mapping. This is a
87	<	* place-holder for an upcoming JDK8 interface.
103	>	* A function computing a mapping from the given key to a value.
104	>	* This is a place-holder for an upcoming JDK8 interface.
105		*/
106		public static interface MappingFunction<K, V> {
107		/**
108	<	* Returns a value for the given key, or null if there is no
92	<	* mapping. If this function throws an (unchecked) exception,
93	<	* the exception is rethrown to its caller, and no mapping is
94	<	* recorded.  Because this function is invoked within
95	<	* atomicity control, the computation should be short and
96	<	* simple. The most common usage is to construct a new object
97	<	* serving as an initial mapped value.
108	>	* Returns a value for the given key, or null if there is no mapping
109		*
110		* @param key the (non-null) key
111	<	* @return a value, or null if none
111	>	* @return a value for the key, or null if none
112		*/
113		V map(K key);
114		}
115
116	+	/**
117	+	* A function computing a new mapping given a key and its current
118	+	* mapped value (or {@code null} if there is no current
119	+	* mapping). This is a place-holder for an upcoming JDK8
120	+	* interface.
121	+	*/
122	+	public static interface RemappingFunction<K, V> {
123	+	/**
124	+	* Returns a new value given a key and its current value.
125	+	*
126	+	* @param key the (non-null) key
127	+	* @param value the current value, or null if there is no mapping
128	+	* @return a value for the key, or null if none
129	+	*/
130	+	V remap(K key, V value);
131	+	}
132	+
133	+	/**
134	+	* A partitionable iterator. A Spliterator can be traversed
135	+	* directly, but can also be partitioned (before traversal) by
136	+	* creating another Spliterator that covers a non-overlapping
137	+	* portion of the elements, and so may be amenable to parallel
138	+	* execution.
139	+	*
140	+	* <p> This interface exports a subset of expected JDK8
141	+	* functionality.
142	+	*
143	+	* <p>Sample usage: Here is one (of the several) ways to compute
144	+	* the sum of the values held in a map using the ForkJoin
145	+	* framework. As illustrated here, Spliterators are well suited to
146	+	* designs in which a task repeatedly splits off half its work
147	+	* into forked subtasks until small enough to process directly,
148	+	* and then joins these subtasks. Variants of this style can be
149	+	* also be used in completion-based designs.
150	+	*
151	+	* <pre>
152	+	* {@code ConcurrentHashMapV8<String, Long> m = ...
153	+	* // Uses parallel depth of log2 of size / (parallelism * slack of 8).
154	+	* int depth = 32 - Integer.numberOfLeadingZeros(m.size() / (aForkJoinPool.getParallelism() * 8));
155	+	* long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), depth, null));
156	+	* // ...
157	+	* static class SumValues extends RecursiveTask<Long> {
158	+	*   final Spliterator<Long> s;
159	+	*   final int depth;             // number of splits before processing
160	+	*   final SumValues nextJoin;    // records forked subtasks to join
161	+	*   SumValues(Spliterator<Long> s, int depth, SumValues nextJoin) {
162	+	*     this.s = s; this.depth = depth; this.nextJoin = nextJoin;
163	+	*   }
164	+	*   public Long compute() {
165	+	*     long sum = 0;
166	+	*     SumValues subtasks = null; // fork subtasks
167	+	*     for (int d = depth - 1; d >= 0; --d)
168	+	*       (subtasks = new SumValues(s.split(), d, subtasks)).fork();
169	+	*     while (s.hasNext())        // directly process remaining elements
170	+	*       sum += s.next();
171	+	*     for (SumValues t = subtasks; t != null; t = t.nextJoin)
172	+	*       sum += t.join();         // collect subtask results
173	+	*     return sum;
174	+	*   }
175	+	* }
176	+	* }</pre>
177	+	*/
178	+	public static interface Spliterator<T> extends Iterator<T> {
179	+	/**
180	+	* Returns a Spliterator covering approximately half of the
181	+	* elements, guaranteed not to overlap with those subsequently
182	+	* returned by this Spliterator.  After invoking this method,
183	+	* the current Spliterator will <em>not</em> produce any of
184	+	* the elements of the returned Spliterator, but the two
185	+	* Spliterators together will produce all of the elements that
186	+	* would have been produced by this Spliterator had this
187	+	* method not been called. The exact number of elements
188	+	* produced by the returned Spliterator is not guaranteed, and
189	+	* may be zero (i.e., with {@code hasNext()} reporting {@code
190	+	* false}) if this Spliterator cannot be further split.
191	+	*
192	+	* @return a Spliterator covering approximately half of the
193	+	* elements
194	+	* @throws IllegalStateException if this Spliterator has
195	+	* already commenced traversing elements.
196	+	*/
197	+	Spliterator<T> split();
198	+
199	+	/**
200	+	* Returns a Spliterator producing the same elements as this
201	+	* Spliterator. This method may be used for example to create
202	+	* a second Spliterator before a traversal, in order to later
203	+	* perform a second traversal.
204	+	*
205	+	* @return a Spliterator covering the same range as this Spliterator.
206	+	* @throws IllegalStateException if this Spliterator has
207	+	* already commenced traversing elements.
208	+	*/
209	+	Spliterator<T> clone();
210	+	}
211	+
212		/*
213		* Overview:
214		*
215		* The primary design goal of this hash table is to maintain
216		* concurrent readability (typically method get(), but also
217		* iterators and related methods) while minimizing update
218	<	* contention.
218	>	* contention. Secondary goals are to keep space consumption about
219	>	* the same or better than java.util.HashMap, and to support high
220	>	* initial insertion rates on an empty table by many threads.
221		*
222		* Each key-value mapping is held in a Node.  Because Node fields
223		* can contain special values, they are defined using plain Object
224		* types. Similarly in turn, all internal methods that use them
225	<	* work off Object types. All public generic-typed methods relay
226	<	* in/out of these internal methods, supplying casts as needed.
225	>	* work off Object types. And similarly, so do the internal
226	>	* methods of auxiliary iterator and view classes.  All public
227	>	* generic typed methods relay in/out of these internal methods,
228	>	* supplying null-checks and casts as needed. This also allows
229	>	* many of the public methods to be factored into a smaller number
230	>	* of internal methods (although sadly not so for the five
231	>	* variants of put-related operations). The validation-based
232	>	* approach explained below leads to a lot of code sprawl because
233	>	* retry-control precludes factoring into smaller methods.
234		*
235		* The table is lazily initialized to a power-of-two size upon the
236	<	* first insertion.  Each bin in the table contains a (typically
237	<	* short) list of Nodes.  Table accesses require volatile/atomic
238	<	* reads, writes, and CASes.  Because there is no other way to
239	<	* arrange this without adding further indirections, we use
240	<	* intrinsics (sun.misc.Unsafe) operations.  The lists of nodes
241	<	* within bins are always accurately traversable under volatile
242	<	* reads, so long as lookups check hash code and non-nullness of
243	<	* key and value before checking key equality. (All valid hash
244	<	* codes are nonnegative. Negative values are reserved for special
245	<	* forwarding nodes; see below.)
246	<	*
247	<	* A bin may be locked during update (insert, delete, and replace)
248	<	* operations.  We do not want to waste the space required to
249	<	* associate a distinct lock object with each bin, so instead use
250	<	* the first node of a bin list itself as a lock, using builtin
251	<	* "synchronized" locks. These save space and we can live with
252	<	* only plain block-structured lock/unlock operations. Using the
253	<	* first node of a list as a lock does not by itself suffice
254	<	* though: When a node is locked, any update must first validate
255	<	* that it is still the first node, and retry if not. (Because new
256	<	* nodes are always appended to lists, once a node is first in a
257	<	* bin, it remains first until deleted or the bin becomes
258	<	* invalidated.)  However, update operations can and usually do
259	<	* still traverse the bin until the point of update, which helps
260	<	* reduce cache misses on retries.  This is a converse of sorts to
261	<	* the lazy locking technique described by Herlihy & Shavit. If
262	<	* there is no existing node during a put operation, then one can
263	<	* be CAS'ed in (without need for lock except in computeIfAbsent);
264	<	* the CAS serves as validation. This is on average the most
265	<	* common case for put operations. The expected number of locks
266	<	* covering different elements (i.e., bins with 2 or more nodes)
267	<	* is approximately 10% at steady state under default settings.
268	<	* Lock contention probability for two threads accessing arbitrary
269	<	* distinct elements is thus less than 1% even for small tables.
270	<	*
271	<	* The table is resized when occupancy exceeds a threshold.  Only
272	<	* a single thread performs the resize (using field "resizing", to
273	<	* arrange exclusion), but the table otherwise remains usable for
274	<	* both reads and updates. Resizing proceeds by transferring bins,
275	<	* one by one, from the table to the next table.  Upon transfer,
276	<	* the old table bin contains only a special forwarding node (with
277	<	* negative hash code ("MOVED")) that contains the next table as
236	>	* first insertion.  Each bin in the table normally contains a
237	>	* list of Nodes (most often, the list has only zero or one Node).
238	>	* Table accesses require volatile/atomic reads, writes, and
239	>	* CASes.  Because there is no other way to arrange this without
240	>	* adding further indirections, we use intrinsics
241	>	* (sun.misc.Unsafe) operations.  The lists of nodes within bins
242	>	* are always accurately traversable under volatile reads, so long
243	>	* as lookups check hash code and non-nullness of value before
244	>	* checking key equality.
245	>	*
246	>	* We use the top two bits of Node hash fields for control
247	>	* purposes -- they are available anyway because of addressing
248	>	* constraints.  As explained further below, these top bits are
249	>	* used as follows:
250	>	*  00 - Normal
251	>	*  01 - Locked
252	>	*  11 - Locked and may have a thread waiting for lock
253	>	*  10 - Node is a forwarding node
254	>	*
255	>	* The lower 30 bits of each Node's hash field contain a
256	>	* transformation of the key's hash code, except for forwarding
257	>	* nodes, for which the lower bits are zero (and so always have
258	>	* hash field == MOVED).
259	>	*
260	>	* Insertion (via put or its variants) of the first node in an
261	>	* empty bin is performed by just CASing it to the bin.  This is
262	>	* by far the most common case for put operations under most
263	>	* key/hash distributions.  Other update operations (insert,
264	>	* delete, and replace) require locks.  We do not want to waste
265	>	* the space required to associate a distinct lock object with
266	>	* each bin, so instead use the first node of a bin list itself as
267	>	* a lock. Blocking support for these locks relies on the builtin
268	>	* "synchronized" monitors.  However, we also need a tryLock
269	>	* construction, so we overlay these by using bits of the Node
270	>	* hash field for lock control (see above), and so normally use
271	>	* builtin monitors only for blocking and signalling using
272	>	* wait/notifyAll constructions. See Node.tryAwaitLock.
273	>	*
274	>	* Using the first node of a list as a lock does not by itself
275	>	* suffice though: When a node is locked, any update must first
276	>	* validate that it is still the first node after locking it, and
277	>	* retry if not. Because new nodes are always appended to lists,
278	>	* once a node is first in a bin, it remains first until deleted
279	>	* or the bin becomes invalidated (upon resizing).  However,
280	>	* operations that only conditionally update may inspect nodes
281	>	* until the point of update. This is a converse of sorts to the
282	>	* lazy locking technique described by Herlihy & Shavit.
283	>	*
284	>	* The main disadvantage of per-bin locks is that other update
285	>	* operations on other nodes in a bin list protected by the same
286	>	* lock can stall, for example when user equals() or mapping
287	>	* functions take a long time.  However, statistically, under
288	>	* random hash codes, this is not a common problem.  Ideally, the
289	>	* frequency of nodes in bins follows a Poisson distribution
290	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
291	>	* parameter of about 0.5 on average, given the resizing threshold
292	>	* of 0.75, although with a large variance because of resizing
293	>	* granularity. Ignoring variance, the expected occurrences of
294	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
295	>	* first values are:
296	>	*
297	>	* 0:    0.60653066
298	>	* 1:    0.30326533
299	>	* 2:    0.07581633
300	>	* 3:    0.01263606
301	>	* 4:    0.00157952
302	>	* 5:    0.00015795
303	>	* 6:    0.00001316
304	>	* 7:    0.00000094
305	>	* 8:    0.00000006
306	>	* more: less than 1 in ten million
307	>	*
308	>	* Lock contention probability for two threads accessing distinct
309	>	* elements is roughly 1 / (8 * #elements) under random hashes.
310	>	*
311	>	* Actual hash code distributions encountered in practice
312	>	* sometimes deviate significantly from uniform randomness.  This
313	>	* includes the case when N > (1<<30), so some keys MUST collide.
314	>	* Similarly for dumb or hostile usages in which multiple keys are
315	>	* designed to have identical hash codes. Also, although we guard
316	>	* against the worst effects of this (see method spread), sets of
317	>	* hashes may differ only in bits that do not impact their bin
318	>	* index for a given power-of-two mask.  So we use a secondary
319	>	* strategy that applies when the number of nodes in a bin exceeds
320	>	* a threshold, and at least one of the keys implements
321	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
322	>	* (a specialized form of red-black trees), bounding search time
323	>	* to O(log N).  Each search step in a TreeBin is around twice as
324	>	* slow as in a regular list, but given that N cannot exceed
325	>	* (1<<64) (before running out of addresses) this bounds search
326	>	* steps, lock hold times, etc, to reasonable constants (roughly
327	>	* 100 nodes inspected per operation worst case) so long as keys
328	>	* are Comparable (which is very common -- String, Long, etc).
329	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
330	>	* traversal pointers as regular nodes, so can be traversed in
331	>	* iterators in the same way.
332	>	*
333	>	* The table is resized when occupancy exceeds a percentage
334	>	* threshold (nominally, 0.75, but see below).  Only a single
335	>	* thread performs the resize (using field "sizeCtl", to arrange
336	>	* exclusion), but the table otherwise remains usable for reads
337	>	* and updates. Resizing proceeds by transferring bins, one by
338	>	* one, from the table to the next table.  Because we are using
339	>	* power-of-two expansion, the elements from each bin must either
340	>	* stay at same index, or move with a power of two offset. We
341	>	* eliminate unnecessary node creation by catching cases where old
342	>	* nodes can be reused because their next fields won't change.  On
343	>	* average, only about one-sixth of them need cloning when a table
344	>	* doubles. The nodes they replace will be garbage collectable as
345	>	* soon as they are no longer referenced by any reader thread that
346	>	* may be in the midst of concurrently traversing table.  Upon
347	>	* transfer, the old table bin contains only a special forwarding
348	>	* node (with hash field "MOVED") that contains the next table as
349		* its key. On encountering a forwarding node, access and update
350	<	* operations restart, using the new table. To ensure concurrent
351	<	* readability of traversals, transfers must proceed from the last
352	<	* bin (table.length - 1) up towards the first.  Any traversal
353	<	* starting from the first bin can then arrange to move to the new
354	<	* table for the rest of the traversal without revisiting nodes.
355	<	* This constrains bin transfers to a particular order, and so can
356	<	* block indefinitely waiting for the next lock, and other threads
357	<	* cannot help with the transfer. However, expected stalls are
358	<	* infrequent enough to not warrant the additional overhead and
359	<	* complexity of access and iteration schemes that could admit
360	<	* out-of-order or concurrent bin transfers.
361	<	*
362	<	* A similar traversal scheme (not yet implemented) can apply to
363	<	* partial traversals during partitioned aggregate operations.
364	<	* Also, read-only operations give up if ever forwarded to a null
365	<	* table, which provides support for shutdown-style clearing,
366	<	* which is also not currently implemented.
350	>	* operations restart, using the new table.
351	>	*
352	>	* Each bin transfer requires its bin lock. However, unlike other
353	>	* cases, a transfer can skip a bin if it fails to acquire its
354	>	* lock, and revisit it later (unless it is a TreeBin). Method
355	>	* rebuild maintains a buffer of TRANSFER_BUFFER_SIZE bins that
356	>	* have been skipped because of failure to acquire a lock, and
357	>	* blocks only if none are available (i.e., only very rarely).
358	>	* The transfer operation must also ensure that all accessible
359	>	* bins in both the old and new table are usable by any traversal.
360	>	* When there are no lock acquisition failures, this is arranged
361	>	* simply by proceeding from the last bin (table.length - 1) up
362	>	* towards the first.  Upon seeing a forwarding node, traversals
363	>	* (see class InternalIterator) arrange to move to the new table
364	>	* without revisiting nodes.  However, when any node is skipped
365	>	* during a transfer, all earlier table bins may have become
366	>	* visible, so are initialized with a reverse-forwarding node back
367	>	* to the old table until the new ones are established. (This
368	>	* sometimes requires transiently locking a forwarding node, which
369	>	* is possible under the above encoding.) These more expensive
370	>	* mechanics trigger only when necessary.
371	>	*
372	>	* The traversal scheme also applies to partial traversals of
373	>	* ranges of bins (via an alternate InternalIterator constructor)
374	>	* to support partitioned aggregate operations.  Also, read-only
375	>	* operations give up if ever forwarded to a null table, which
376	>	* provides support for shutdown-style clearing, which is also not
377	>	* currently implemented.
378	>	*
379	>	* Lazy table initialization minimizes footprint until first use,
380	>	* and also avoids resizings when the first operation is from a
381	>	* putAll, constructor with map argument, or deserialization.
382	>	* These cases attempt to override the initial capacity settings,
383	>	* but harmlessly fail to take effect in cases of races.
384		*
385		* The element count is maintained using a LongAdder, which avoids
386		* contention on updates but can encounter cache thrashing if read
387	<	* too frequently during concurrent updates. To avoid reading so
388	<	* often, resizing is normally attempted only upon adding to a bin
389	<	* already holding two or more nodes. Under the default threshold
390	<	* (0.75), and uniform hash distributions, the probability of this
391	<	* occurring at threshold is around 13%, meaning that only about 1
392	<	* in 8 puts check threshold (and after resizing, many fewer do
393	<	* so). But this approximation has high variance for small table
394	<	* sizes, so we check on any collision for sizes <= 64.  Further,
395	<	* to increase the probablity that a resize occurs soon enough, we
396	<	* offset the threshold (see THRESHOLD_OFFSET) by the expected
397	<	* number of puts between checks. This is currently set to 8, in
398	<	* accord with the default load factor. In practice, this is
399	<	* rarely overridden, and in any case is close enough to other
400	<	* plausible values not to waste dynamic probablity computation
401	<	* for more precision.
387	>	* too frequently during concurrent access. To avoid reading so
388	>	* often, resizing is attempted either when a bin lock is
389	>	* contended, or upon adding to a bin already holding two or more
390	>	* nodes (checked before adding in the xIfAbsent methods, after
391	>	* adding in others). Under uniform hash distributions, the
392	>	* probability of this occurring at threshold is around 13%,
393	>	* meaning that only about 1 in 8 puts check threshold (and after
394	>	* resizing, many fewer do so). But this approximation has high
395	>	* variance for small table sizes, so we check on any collision
396	>	* for sizes <= 64. The bulk putAll operation further reduces
397	>	* contention by only committing count updates upon these size
398	>	* checks.
399	>	*
400	>	* Maintaining API and serialization compatibility with previous
401	>	* versions of this class introduces several oddities. Mainly: We
402	>	* leave untouched but unused constructor arguments refering to
403	>	* concurrencyLevel. We accept a loadFactor constructor argument,
404	>	* but apply it only to initial table capacity (which is the only
405	>	* time that we can guarantee to honor it.) We also declare an
406	>	* unused "Segment" class that is instantiated in minimal form
407	>	* only when serializing.
408		*/
409
410		/* ---------------- Constants -------------- */
411
412		/**
413	<	* The smallest allowed table capacity.  Must be a power of 2, at
414	<	* least 2.
413	>	* The largest possible table capacity.  This value must be
414	>	* exactly 1<<30 to stay within Java array allocation and indexing
415	>	* bounds for power of two table sizes, and is further required
416	>	* because the top two bits of 32bit hash fields are used for
417	>	* control purposes.
418		*/
419	<	static final int MINIMUM_CAPACITY = 2;
419	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
420
421		/**
422	<	* The largest allowed table capacity.  Must be a power of 2, at
423	<	* most 1<<30.
422	>	* The default initial table capacity.  Must be a power of 2
423	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
424		*/
425	<	static final int MAXIMUM_CAPACITY = 1 << 30;
425	>	private static final int DEFAULT_CAPACITY = 16;
426
427		/**
428	<	* The default initial table capacity.  Must be a power of 2, at
429	<	* least MINIMUM_CAPACITY and at most MAXIMUM_CAPACITY
428	>	* The largest possible (non-power of two) array size.
429	>	* Needed by toArray and related methods.
430		*/
431	<	static final int DEFAULT_CAPACITY = 16;
431	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
432
433		/**
434	<	* The default load factor for this table, used when not otherwise
435	<	* specified in a constructor.
434	>	* The default concurrency level for this table. Unused but
435	>	* defined for compatibility with previous versions of this class.
436		*/
437	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
437	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
438
439		/**
440	<	* The default concurrency level for this table. Unused, but
441	<	* defined for compatibility with previous versions of this class.
440	>	* The load factor for this table. Overrides of this value in
441	>	* constructors affect only the initial table capacity.  The
442	>	* actual floating point value isn't normally used -- it is
443	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
444	>	* the associated resizing threshold.
445		*/
446	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
446	>	private static final float LOAD_FACTOR = 0.75f;
447
448		/**
449	<	* The count value to offset thesholds to compensate for checking
450	<	* for resizing only when inserting into bins with two or more
451	<	* elements. See above for explanation.
449	>	* The buffer size for skipped bins during transfers. The
450	>	* value is arbitrary but should be large enough to avoid
451	>	* most locking stalls during resizes.
452		*/
453	<	static final int THRESHOLD_OFFSET = 8;
453	>	private static final int TRANSFER_BUFFER_SIZE = 32;
454
455		/**
456	<	* Special node hash value indicating to use table in node.key
457	<	* Must be negative.
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	>	private static final int TREE_THRESHOLD = 8;
461	>
462	>	/*
463	>	* Encodings for special uses of Node hash fields. See above for
464	>	* explanation.
465		*/
466	<	static final int MOVED = -1;
466	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
467	>	static final int LOCKED    = 0x40000000; // set/tested only as a bit
468	>	static final int WAITING   = 0xc0000000; // both bits set/tested together
469	>	static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
470
471		/* ---------------- Fields -------------- */
472
473		/**
474		* The array of bins. Lazily initialized upon first insertion.
475	<	* Size is always a power of two. Accessed directly by inner
250	<	* classes.
475	>	* Size is always a power of two. Accessed directly by iterators.
476		*/
477		transient volatile Node[] table;
478
479	<	/** The counter maintaining number of elements. */
479	>	/**
480	>	* The counter maintaining number of elements.
481	>	*/
482		private transient final LongAdder counter;
483	<	/** Nonzero when table is being initialized or resized. Updated via CAS. */
484	<	private transient volatile int resizing;
485	<	/** The target load factor for the table. */
486	<	private transient float loadFactor;
487	<	/** The next element count value upon which to resize the table. */
488	<	private transient int threshold;
489	<	/** The initial capacity of the table. */
490	<	private transient int initCap;
483	>
484	>	/**
485	>	* Table initialization and resizing control.  When negative, the
486	>	* table is being initialized or resized. Otherwise, when table is
487	>	* null, holds the initial table size to use upon creation, or 0
488	>	* for default. After initialization, holds the next element count
489	>	* value upon which to resize the table.
490	>	*/
491	>	private transient volatile int sizeCtl;
492
493		// views
494	<	transient Set<K> keySet;
495	<	transient Set<Map.Entry<K,V>> entrySet;
496	<	transient Collection<V> values;
269	<
270	<	/** For serialization compatability. Null unless serialized; see below */
271	<	Segment<K,V>[] segments;
494	>	private transient KeySet<K,V> keySet;
495	>	private transient Values<K,V> values;
496	>	private transient EntrySet<K,V> entrySet;
497
498	<	/**
499	<	* Applies a supplemental hash function to a given hashCode, which
500	<	* defends against poor quality hash functions.  The result must
501	<	* be non-negative, and for reasonable performance must have good
502	<	* avalanche properties; i.e., that each bit of the argument
503	<	* affects each bit (except sign bit) of the result.
498	>	/** For serialization compatibility. Null unless serialized; see below */
499	>	private Segment<K,V>[] segments;
500	>
501	>	/* ---------------- Table element access -------------- */
502	>
503	>	/*
504	>	* Volatile access methods are used for table elements as well as
505	>	* elements of in-progress next table while resizing.  Uses are
506	>	* null checked by callers, and implicitly bounds-checked, relying
507	>	* on the invariants that tab arrays have non-zero size, and all
508	>	* indices are masked with (tab.length - 1) which is never
509	>	* negative and always less than length. Note that, to be correct
510	>	* wrt arbitrary concurrency errors by users, bounds checks must
511	>	* operate on local variables, which accounts for some odd-looking
512	>	* inline assignments below.
513		*/
514	<	private static final int spread(int h) {
515	<	// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
516	<	h ^= h >>> 16;
517	<	h *= 0x85ebca6b;
518	<	h ^= h >>> 13;
519	<	h *= 0xc2b2ae35;
520	<	return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit
514	>
515	>	static final Node tabAt(Node[] tab, int i) { // used by InternalIterator
516	>	return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
517	>	}
518	>
519	>	private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) {
520	>	return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v);
521	>	}
522	>
523	>	private static final void setTabAt(Node[] tab, int i, Node v) {
524	>	UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
525		}
526
527	+	/* ---------------- Nodes -------------- */
528	+
529		/**
530		* Key-value entry. Note that this is never exported out as a
531	<	* user-visible Map.Entry.
531	>	* user-visible Map.Entry (see MapEntry below). Nodes with a hash
532	>	* field of MOVED are special, and do not contain user keys or
533	>	* values.  Otherwise, keys are never null, and null val fields
534	>	* indicate that a node is in the process of being deleted or
535	>	* created. For purposes of read-only access, a key may be read
536	>	* before a val, but can only be used after checking val to be
537	>	* non-null.
538		*/
539	<	static final class Node {
540	<	final int hash;
539	>	static class Node {
540	>	volatile int hash;
541		final Object key;
542		volatile Object val;
543		volatile Node next;
#	Line 302 | Line 548 | public class ConcurrentHashMapV8<K, V>
548		this.val = val;
549		this.next = next;
550		}
305	–	}
551
552	<	/*
553	<	* Volatile access nethods are used for table elements as well as
554	<	* elements of in-progress next table while resizing.  Uses in
555	<	* access and update methods are null checked by callers, and
311	<	* implicitly bounds-checked, relying on the invariants that tab
312	<	* arrays have non-zero size, and all indices are masked with
313	<	* (tab.length - 1) which is never negative and always less than
314	<	* length. The "relaxed" non-volatile forms are used only during
315	<	* table initialization. The only other usage is in
316	<	* HashIterator.advance, which performs explicit checks.
317	<	*/
552	>	/** CompareAndSet the hash field */
553	>	final boolean casHash(int cmp, int val) {
554	>	return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
555	>	}
556
557	<	static final Node tabAt(Node[] tab, int i) { // used in HashIterator
558	<	return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
559	<	}
557	>	/** The number of spins before blocking for a lock */
558	>	static final int MAX_SPINS =
559	>	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
560
561	<	private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) {
562	<	return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v);
563	<	}
561	>	/**
562	>	* Spins a while if LOCKED bit set and this node is the first
563	>	* of its bin, and then sets WAITING bits on hash field and
564	>	* blocks (once) if they are still set.  It is OK for this
565	>	* method to return even if lock is not available upon exit,
566	>	* which enables these simple single-wait mechanics.
567	>	*
568	>	* The corresponding signalling operation is performed within
569	>	* callers: Upon detecting that WAITING has been set when
570	>	* unlocking lock (via a failed CAS from non-waiting LOCKED
571	>	* state), unlockers acquire the sync lock and perform a
572	>	* notifyAll.
573	>	*/
574	>	final void tryAwaitLock(Node[] tab, int i) {
575	>	if (tab != null && i >= 0 && i < tab.length) { // bounds check
576	>	int r = ThreadLocalRandom.current().nextInt(); // randomize spins
577	>	int spins = MAX_SPINS, h;
578	>	while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
579	>	if (spins >= 0) {
580	>	r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
581	>	if (r >= 0 && --spins == 0)
582	>	Thread.yield();  // yield before block
583	>	}
584	>	else if (casHash(h, h | WAITING)) {
585	>	synchronized (this) {
586	>	if (tabAt(tab, i) == this &&
587	>	(hash & WAITING) == WAITING) {
588	>	try {
589	>	wait();
590	>	} catch (InterruptedException ie) {
591	>	Thread.currentThread().interrupt();
592	>	}
593	>	}
594	>	else
595	>	notifyAll(); // possibly won race vs signaller
596	>	}
597	>	break;
598	>	}
599	>	}
600	>	}
601	>	}
602
603	<	private static final void setTabAt(Node[] tab, int i, Node v) {
604	<	UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
605	<	}
603	>	// Unsafe mechanics for casHash
604	>	private static final sun.misc.Unsafe UNSAFE;
605	>	private static final long hashOffset;
606
607	<	private static final Node relaxedTabAt(Node[] tab, int i) {
608	<	return (Node)UNSAFE.getObject(tab, ((long)i<<ASHIFT)+ABASE);
607	>	static {
608	>	try {
609	>	UNSAFE = getUnsafe();
610	>	Class<?> k = Node.class;
611	>	hashOffset = UNSAFE.objectFieldOffset
612	>	(k.getDeclaredField("hash"));
613	>	} catch (Exception e) {
614	>	throw new Error(e);
615	>	}
616	>	}
617		}
618
619	<	private static final void relaxedSetTabAt(Node[] tab, int i, Node v) {
620	<	UNSAFE.putObject(tab, ((long)i<<ASHIFT)+ABASE, v);
619	>	/* ---------------- TreeBins -------------- */
620	>
621	>	/**
622	>	* Nodes for use in TreeBins
623	>	*/
624	>	static final class TreeNode extends Node {
625	>	TreeNode parent;  // red-black tree links
626	>	TreeNode left;
627	>	TreeNode right;
628	>	TreeNode prev;    // needed to unlink next upon deletion
629	>	boolean red;
630	>
631	>	TreeNode(int hash, Object key, Object val, Node next, TreeNode parent) {
632	>	super(hash, key, val, next);
633	>	this.parent = parent;
634	>	}
635		}
636
637	<	/* ---------------- Access and update operations -------------- */
637	>	/**
638	>	* A specialized form of red-black tree for use in bins
639	>	* whose size exceeds a threshold.
640	>	*
641	>	* TreeBins use a special form of comparison for search and
642	>	* related operations (which is the main reason we cannot use
643	>	* existing collections such as TreeMaps). TreeBins contain
644	>	* Comparable elements, but may contain others, as well as
645	>	* elements that are Comparable but not necessarily Comparable<T>
646	>	* for the same T, so we cannot invoke compareTo among them. To
647	>	* handle this, the tree is ordered primarily by hash value, then
648	>	* by getClass().getName() order, and then by Comparator order
649	>	* among elements of the same class.  On lookup at a node, if
650	>	* elements are not comparable or compare as 0, both left and
651	>	* right children may need to be searched in the case of tied hash
652	>	* values. (This corresponds to the full list search that would be
653	>	* necessary if all elements were non-Comparable and had tied
654	>	* hashes.)  The red-black balancing code is updated from
655	>	* pre-jdk-collections
656	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
657	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
658	>	* Algorithms" (CLR).
659	>	*
660	>	* TreeBins also maintain a separate locking discipline than
661	>	* regular bins. Because they are forwarded via special MOVED
662	>	* nodes at bin heads (which can never change once established),
663	>	* we cannot use use those nodes as locks. Instead, TreeBin
664	>	* extends AbstractQueuedSynchronizer to support a simple form of
665	>	* read-write lock. For update operations and table validation,
666	>	* the exclusive form of lock behaves in the same way as bin-head
667	>	* locks. However, lookups use shared read-lock mechanics to allow
668	>	* multiple readers in the absence of writers.  Additionally,
669	>	* these lookups do not ever block: While the lock is not
670	>	* available, they proceed along the slow traversal path (via
671	>	* next-pointers) until the lock becomes available or the list is
672	>	* exhausted, whichever comes first. (These cases are not fast,
673	>	* but maximize aggregate expected throughput.)  The AQS mechanics
674	>	* for doing this are straightforward.  The lock state is held as
675	>	* AQS getState().  Read counts are negative; the write count (1)
676	>	* is positive.  There are no signalling preferences among readers
677	>	* and writers. Since we don't need to export full Lock API, we
678	>	* just override the minimal AQS methods and use them directly.
679	>	*/
680	>	static final class TreeBin extends AbstractQueuedSynchronizer {
681	>	private static final long serialVersionUID = 2249069246763182397L;
682	>	transient TreeNode root;  // root of tree
683	>	transient TreeNode first; // head of next-pointer list
684
685	<	/** Implementation for get and containsKey **/
686	<	private final Object internalGet(Object k) {
687	<	int h = spread(k.hashCode());
688	<	Node[] tab = table;
689	<	retry: while (tab != null) {
690	<	Node e = tabAt(tab, (tab.length - 1) & h);
691	<	while (e != null) {
692	<	int eh = e.hash;
693	<	if (eh == h) {
694	<	Object ek = e.key, ev = e.val;
695	<	if (ev != null && ek != null && (k == ek || k.equals(ek)))
696	<	return ev;
697	<	}
698	<	else if (eh < 0) { // bin was moved during resize
699	<	tab = (Node[])e.key;
700	<	continue retry;
685	>	/* AQS overrides */
686	>	public final boolean isHeldExclusively() { return getState() > 0; }
687	>	public final boolean tryAcquire(int ignore) {
688	>	if (compareAndSetState(0, 1)) {
689	>	setExclusiveOwnerThread(Thread.currentThread());
690	>	return true;
691	>	}
692	>	return false;
693	>	}
694	>	public final boolean tryRelease(int ignore) {
695	>	setExclusiveOwnerThread(null);
696	>	setState(0);
697	>	return true;
698	>	}
699	>	public final int tryAcquireShared(int ignore) {
700	>	for (int c;;) {
701	>	if ((c = getState()) > 0)
702	>	return -1;
703	>	if (compareAndSetState(c, c -1))
704	>	return 1;
705	>	}
706	>	}
707	>	public final boolean tryReleaseShared(int ignore) {
708	>	int c;
709	>	do {} while (!compareAndSetState(c = getState(), c + 1));
710	>	return c == -1;
711	>	}
712	>
713	>	/** From CLR */
714	>	private void rotateLeft(TreeNode p) {
715	>	if (p != null) {
716	>	TreeNode r = p.right, pp, rl;
717	>	if ((rl = p.right = r.left) != null)
718	>	rl.parent = p;
719	>	if ((pp = r.parent = p.parent) == null)
720	>	root = r;
721	>	else if (pp.left == p)
722	>	pp.left = r;
723	>	else
724	>	pp.right = r;
725	>	r.left = p;
726	>	p.parent = r;
727	>	}
728	>	}
729	>
730	>	/** From CLR */
731	>	private void rotateRight(TreeNode p) {
732	>	if (p != null) {
733	>	TreeNode l = p.left, pp, lr;
734	>	if ((lr = p.left = l.right) != null)
735	>	lr.parent = p;
736	>	if ((pp = l.parent = p.parent) == null)
737	>	root = l;
738	>	else if (pp.right == p)
739	>	pp.right = l;
740	>	else
741	>	pp.left = l;
742	>	l.right = p;
743	>	p.parent = l;
744	>	}
745	>	}
746	>
747	>	/**
748	>	* Return the TreeNode (or null if not found) for the given key
749	>	* starting at given root.
750	>	*/
751	>	@SuppressWarnings("unchecked") // suppress Comparable cast warning
752	>	final TreeNode getTreeNode(int h, Object k, TreeNode p) {
753	>	Class<?> c = k.getClass();
754	>	while (p != null) {
755	>	int dir, ph;  Object pk; Class<?> pc;
756	>	if ((ph = p.hash) == h) {
757	>	if ((pk = p.key) == k || k.equals(pk))
758	>	return p;
759	>	if (c != (pc = pk.getClass()) ||
760	>	!(k instanceof Comparable) ||
761	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
762	>	dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
763	>	TreeNode r = null, s = null, pl, pr;
764	>	if (dir >= 0) {
765	>	if ((pl = p.left) != null && h <= pl.hash)
766	>	s = pl;
767	>	}
768	>	else if ((pr = p.right) != null && h >= pr.hash)
769	>	s = pr;
770	>	if (s != null && (r = getTreeNode(h, k, s)) != null)
771	>	return r;
772	>	}
773		}
774	<	e = e.next;
774	>	else
775	>	dir = (h < ph) ? -1 : 1;
776	>	p = (dir > 0) ? p.right : p.left;
777		}
778	<	break;
778	>	return null;
779		}
362	–	return null;
363	–	}
780
781	<	/** Implementation for put and putIfAbsent **/
782	<	private final Object internalPut(Object k, Object v, boolean replace) {
783	<	int h = spread(k.hashCode());
784	<	Object oldVal = null;  // the previous value or null if none
785	<	Node[] tab = table;
786	<	for (;;) {
787	<	Node e; int i;
788	<	if (tab == null)
789	<	tab = grow(0);
790	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
791	<	if (casTabAt(tab, i, null, new Node(h, k, v, null)))
781	>	/**
782	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
783	>	* read-lock to call getTreeNode, but during failure to get
784	>	* lock, searches along next links.
785	>	*/
786	>	final Object getValue(int h, Object k) {
787	>	Node r = null;
788	>	int c = getState(); // Must read lock state first
789	>	for (Node e = first; e != null; e = e.next) {
790	>	if (c <= 0 && compareAndSetState(c, c - 1)) {
791	>	try {
792	>	r = getTreeNode(h, k, root);
793	>	} finally {
794	>	releaseShared(0);
795	>	}
796		break;
797	+	}
798	+	else if ((e.hash & HASH_BITS) == h && k.equals(e.key)) {
799	+	r = e;
800	+	break;
801	+	}
802	+	else
803	+	c = getState();
804	+	}
805	+	return r == null ? null : r.val;
806	+	}
807	+
808	+	/**
809	+	* Find or add a node
810	+	* @return null if added
811	+	*/
812	+	@SuppressWarnings("unchecked") // suppress Comparable cast warning
813	+	final TreeNode putTreeNode(int h, Object k, Object v) {
814	+	Class<?> c = k.getClass();
815	+	TreeNode pp = root, p = null;
816	+	int dir = 0;
817	+	while (pp != null) { // find existing node or leaf to insert at
818	+	int ph;  Object pk; Class<?> pc;
819	+	p = pp;
820	+	if ((ph = p.hash) == h) {
821	+	if ((pk = p.key) == k || k.equals(pk))
822	+	return p;
823	+	if (c != (pc = pk.getClass()) ||
824	+	!(k instanceof Comparable) ||
825	+	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
826	+	dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
827	+	TreeNode r = null, s = null, pl, pr;
828	+	if (dir >= 0) {
829	+	if ((pl = p.left) != null && h <= pl.hash)
830	+	s = pl;
831	+	}
832	+	else if ((pr = p.right) != null && h >= pr.hash)
833	+	s = pr;
834	+	if (s != null && (r = getTreeNode(h, k, s)) != null)
835	+	return r;
836	+	}
837	+	}
838	+	else
839	+	dir = (h < ph) ? -1 : 1;
840	+	pp = (dir > 0) ? p.right : p.left;
841	+	}
842	+
843	+	TreeNode f = first;
844	+	TreeNode x = first = new TreeNode(h, k, v, f, p);
845	+	if (p == null)
846	+	root = x;
847	+	else { // attach and rebalance; adapted from CLR
848	+	TreeNode xp, xpp;
849	+	if (f != null)
850	+	f.prev = x;
851	+	if (dir <= 0)
852	+	p.left = x;
853	+	else
854	+	p.right = x;
855	+	x.red = true;
856	+	while (x != null && (xp = x.parent) != null && xp.red &&
857	+	(xpp = xp.parent) != null) {
858	+	TreeNode xppl = xpp.left;
859	+	if (xp == xppl) {
860	+	TreeNode y = xpp.right;
861	+	if (y != null && y.red) {
862	+	y.red = false;
863	+	xp.red = false;
864	+	xpp.red = true;
865	+	x = xpp;
866	+	}
867	+	else {
868	+	if (x == xp.right) {
869	+	rotateLeft(x = xp);
870	+	xpp = (xp = x.parent) == null ? null : xp.parent;
871	+	}
872	+	if (xp != null) {
873	+	xp.red = false;
874	+	if (xpp != null) {
875	+	xpp.red = true;
876	+	rotateRight(xpp);
877	+	}
878	+	}
879	+	}
880	+	}
881	+	else {
882	+	TreeNode y = xppl;
883	+	if (y != null && y.red) {
884	+	y.red = false;
885	+	xp.red = false;
886	+	xpp.red = true;
887	+	x = xpp;
888	+	}
889	+	else {
890	+	if (x == xp.left) {
891	+	rotateRight(x = xp);
892	+	xpp = (xp = x.parent) == null ? null : xp.parent;
893	+	}
894	+	if (xp != null) {
895	+	xp.red = false;
896	+	if (xpp != null) {
897	+	xpp.red = true;
898	+	rotateLeft(xpp);
899	+	}
900	+	}
901	+	}
902	+	}
903	+	}
904	+	TreeNode r = root;
905	+	if (r != null && r.red)
906	+	r.red = false;
907	+	}
908	+	return null;
909	+	}
910	+
911	+	/**
912	+	* Removes the given node, that must be present before this
913	+	* call.  This is messier than typical red-black deletion code
914	+	* because we cannot swap the contents of an interior node
915	+	* with a leaf successor that is pinned by "next" pointers
916	+	* that are accessible independently of lock. So instead we
917	+	* swap the tree linkages.
918	+	*/
919	+	final void deleteTreeNode(TreeNode p) {
920	+	TreeNode next = (TreeNode)p.next; // unlink traversal pointers
921	+	TreeNode pred = p.prev;
922	+	if (pred == null)
923	+	first = next;
924	+	else
925	+	pred.next = next;
926	+	if (next != null)
927	+	next.prev = pred;
928	+	TreeNode replacement;
929	+	TreeNode pl = p.left;
930	+	TreeNode pr = p.right;
931	+	if (pl != null && pr != null) {
932	+	TreeNode s = pr, sl;
933	+	while ((sl = s.left) != null) // find successor
934	+	s = sl;
935	+	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
936	+	TreeNode sr = s.right;
937	+	TreeNode pp = p.parent;
938	+	if (s == pr) { // p was s's direct parent
939	+	p.parent = s;
940	+	s.right = p;
941	+	}
942	+	else {
943	+	TreeNode sp = s.parent;
944	+	if ((p.parent = sp) != null) {
945	+	if (s == sp.left)
946	+	sp.left = p;
947	+	else
948	+	sp.right = p;
949	+	}
950	+	if ((s.right = pr) != null)
951	+	pr.parent = s;
952	+	}
953	+	p.left = null;
954	+	if ((p.right = sr) != null)
955	+	sr.parent = p;
956	+	if ((s.left = pl) != null)
957	+	pl.parent = s;
958	+	if ((s.parent = pp) == null)
959	+	root = s;
960	+	else if (p == pp.left)
961	+	pp.left = s;
962	+	else
963	+	pp.right = s;
964	+	replacement = sr;
965	+	}
966	+	else
967	+	replacement = (pl != null) ? pl : pr;
968	+	TreeNode pp = p.parent;
969	+	if (replacement == null) {
970	+	if (pp == null) {
971	+	root = null;
972	+	return;
973	+	}
974	+	replacement = p;
975		}
378	–	else if (e.hash < 0)
379	–	tab = (Node[])e.key;
976		else {
977	<	boolean validated = false;
978	<	boolean checkSize = false;
979	<	synchronized(e) {
980	<	Node first = e;
981	<	for (;;) {
982	<	Object ek, ev;
983	<	if ((ev = e.val) == null)
984	<	break;
985	<	if (e.hash == h && (ek = e.key) != null &&
986	<	(k == ek || k.equals(ek))) {
987	<	if (tabAt(tab, i) == first) {
988	<	validated = true;
989	<	oldVal = ev;
990	<	if (replace)
991	<	e.val = v;
977	>	replacement.parent = pp;
978	>	if (pp == null)
979	>	root = replacement;
980	>	else if (p == pp.left)
981	>	pp.left = replacement;
982	>	else
983	>	pp.right = replacement;
984	>	p.left = p.right = p.parent = null;
985	>	}
986	>	if (!p.red) { // rebalance, from CLR
987	>	TreeNode x = replacement;
988	>	while (x != null) {
989	>	TreeNode xp, xpl;
990	>	if (x.red || (xp = x.parent) == null) {
991	>	x.red = false;
992	>	break;
993	>	}
994	>	if (x == (xpl = xp.left)) {
995	>	TreeNode sib = xp.right;
996	>	if (sib != null && sib.red) {
997	>	sib.red = false;
998	>	xp.red = true;
999	>	rotateLeft(xp);
1000	>	sib = (xp = x.parent) == null ? null : xp.right;
1001	>	}
1002	>	if (sib == null)
1003	>	x = xp;
1004	>	else {
1005	>	TreeNode sl = sib.left, sr = sib.right;
1006	>	if ((sr == null || !sr.red) &&
1007	>	(sl == null || !sl.red)) {
1008	>	sib.red = true;
1009	>	x = xp;
1010	>	}
1011	>	else {
1012	>	if (sr == null || !sr.red) {
1013	>	if (sl != null)
1014	>	sl.red = false;
1015	>	sib.red = true;
1016	>	rotateRight(sib);
1017	>	sib = (xp = x.parent) == null ? null : xp.right;
1018	>	}
1019	>	if (sib != null) {
1020	>	sib.red = (xp == null) ? false : xp.red;
1021	>	if ((sr = sib.right) != null)
1022	>	sr.red = false;
1023	>	}
1024	>	if (xp != null) {
1025	>	xp.red = false;
1026	>	rotateLeft(xp);
1027	>	}
1028	>	x = root;
1029		}
397	–	break;
1030		}
1031	<	Node last = e;
1032	<	if ((e = e.next) == null) {
1033	<	if (tabAt(tab, i) == first) {
1034	<	validated = true;
1035	<	last.next = new Node(h, k, v, null);
1036	<	if (last != first || tab.length <= 64)
1037	<	checkSize = true;
1031	>	}
1032	>	else { // symmetric
1033	>	TreeNode sib = xpl;
1034	>	if (sib != null && sib.red) {
1035	>	sib.red = false;
1036	>	xp.red = true;
1037	>	rotateRight(xp);
1038	>	sib = (xp = x.parent) == null ? null : xp.left;
1039	>	}
1040	>	if (sib == null)
1041	>	x = xp;
1042	>	else {
1043	>	TreeNode sl = sib.left, sr = sib.right;
1044	>	if ((sl == null || !sl.red) &&
1045	>	(sr == null || !sr.red)) {
1046	>	sib.red = true;
1047	>	x = xp;
1048	>	}
1049	>	else {
1050	>	if (sl == null || !sl.red) {
1051	>	if (sr != null)
1052	>	sr.red = false;
1053	>	sib.red = true;
1054	>	rotateLeft(sib);
1055	>	sib = (xp = x.parent) == null ? null : xp.left;
1056	>	}
1057	>	if (sib != null) {
1058	>	sib.red = (xp == null) ? false : xp.red;
1059	>	if ((sl = sib.left) != null)
1060	>	sl.red = false;
1061	>	}
1062	>	if (xp != null) {
1063	>	xp.red = false;
1064	>	rotateRight(xp);
1065	>	}
1066	>	x = root;
1067		}
407	–	break;
1068		}
1069		}
1070		}
1071	<	if (validated) {
1072	<	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
1073	<	resizing == 0 && counter.sum() >= threshold)
1074	<	grow(0);
1075	<	break;
1071	>	}
1072	>	if (p == replacement && (pp = p.parent) != null) {
1073	>	if (p == pp.left) // detach pointers
1074	>	pp.left = null;
1075	>	else if (p == pp.right)
1076	>	pp.right = null;
1077	>	p.parent = null;
1078	>	}
1079	>	}
1080	>	}
1081	>
1082	>	/* ---------------- Collision reduction methods -------------- */
1083	>
1084	>	/**
1085	>	* Spreads higher bits to lower, and also forces top 2 bits to 0.
1086	>	* Because the table uses power-of-two masking, sets of hashes
1087	>	* that vary only in bits above the current mask will always
1088	>	* collide. (Among known examples are sets of Float keys holding
1089	>	* consecutive whole numbers in small tables.)  To counter this,
1090	>	* we apply a transform that spreads the impact of higher bits
1091	>	* downward. There is a tradeoff between speed, utility, and
1092	>	* quality of bit-spreading. Because many common sets of hashes
1093	>	* are already reasonably distributed across bits (so don't benefit
1094	>	* from spreading), and because we use trees to handle large sets
1095	>	* of collisions in bins, we don't need excessively high quality.
1096	>	*/
1097	>	private static final int spread(int h) {
1098	>	h ^= (h >>> 18) ^ (h >>> 12);
1099	>	return (h ^ (h >>> 10)) & HASH_BITS;
1100	>	}
1101	>
1102	>	/**
1103	>	* Replaces a list bin with a tree bin. Call only when locked.
1104	>	* Fails to replace if the given key is non-comparable or table
1105	>	* is, or needs, resizing.
1106	>	*/
1107	>	private final void replaceWithTreeBin(Node[] tab, int index, Object key) {
1108	>	if ((key instanceof Comparable) &&
1109	>	(tab.length >= MAXIMUM_CAPACITY || counter.sum() < (long)sizeCtl)) {
1110	>	TreeBin t = new TreeBin();
1111	>	for (Node e = tabAt(tab, index); e != null; e = e.next)
1112	>	t.putTreeNode(e.hash & HASH_BITS, e.key, e.val);
1113	>	setTabAt(tab, index, new Node(MOVED, t, null, null));
1114	>	}
1115	>	}
1116	>
1117	>	/* ---------------- Internal access and update methods -------------- */
1118	>
1119	>	/** Implementation for get and containsKey */
1120	>	private final Object internalGet(Object k) {
1121	>	int h = spread(k.hashCode());
1122	>	retry: for (Node[] tab = table; tab != null;) {
1123	>	Node e, p; Object ek, ev; int eh;      // locals to read fields once
1124	>	for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1125	>	if ((eh = e.hash) == MOVED) {
1126	>	if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1127	>	return ((TreeBin)ek).getValue(h, k);
1128	>	else {                        // restart with new table
1129	>	tab = (Node[])ek;
1130	>	continue retry;
1131	>	}
1132		}
1133	+	else if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
1134	+	((ek = e.key) == k || k.equals(ek)))
1135	+	return ev;
1136		}
1137	+	break;
1138		}
1139	<	if (oldVal == null)
420	<	counter.increment();
421	<	return oldVal;
1139	>	return null;
1140		}
1141
1142		/**
1143	<	* Covers the four public remove/replace methods: Replaces node
1144	<	* value with v, conditional upon match of cv if non-null.  If
1145	<	* resulting value is null, delete.
1143	>	* Implementation for the four public remove/replace methods:
1144	>	* Replaces node value with v, conditional upon match of cv if
1145	>	* non-null.  If resulting value is null, delete.
1146		*/
1147		private final Object internalReplace(Object k, Object v, Object cv) {
1148		int h = spread(k.hashCode());
1149		Object oldVal = null;
1150	<	Node e; int i;
1151	<	Node[] tab = table;
1152	<	while (tab != null &&
1153	<	(e = tabAt(tab, i = (tab.length - 1) & h)) != null) {
1154	<	if (e.hash < 0)
1155	<	tab = (Node[])e.key;
1156	<	else {
1150	>	for (Node[] tab = table;;) {
1151	>	Node f; int i, fh; Object fk;
1152	>	if (tab == null ||
1153	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1154	>	break;
1155	>	else if ((fh = f.hash) == MOVED) {
1156	>	if ((fk = f.key) instanceof TreeBin) {
1157	>	TreeBin t = (TreeBin)fk;
1158	>	boolean validated = false;
1159	>	boolean deleted = false;
1160	>	t.acquire(0);
1161	>	try {
1162	>	if (tabAt(tab, i) == f) {
1163	>	validated = true;
1164	>	TreeNode p = t.getTreeNode(h, k, t.root);
1165	>	if (p != null) {
1166	>	Object pv = p.val;
1167	>	if (cv == null || cv == pv || cv.equals(pv)) {
1168	>	oldVal = pv;
1169	>	if ((p.val = v) == null) {
1170	>	deleted = true;
1171	>	t.deleteTreeNode(p);
1172	>	}
1173	>	}
1174	>	}
1175	>	}
1176	>	} finally {
1177	>	t.release(0);
1178	>	}
1179	>	if (validated) {
1180	>	if (deleted)
1181	>	counter.add(-1L);
1182	>	break;
1183	>	}
1184	>	}
1185	>	else
1186	>	tab = (Node[])fk;
1187	>	}
1188	>	else if ((fh & HASH_BITS) != h && f.next == null) // precheck
1189	>	break;                          // rules out possible existence
1190	>	else if ((fh & LOCKED) != 0) {
1191	>	checkForResize();               // try resizing if can't get lock
1192	>	f.tryAwaitLock(tab, i);
1193	>	}
1194	>	else if (f.casHash(fh, fh | LOCKED)) {
1195		boolean validated = false;
1196		boolean deleted = false;
1197	<	synchronized(e) {
1198	<	Node pred = null;
1199	<	Node first = e;
1200	<	for (;;) {
1201	<	Object ek, ev;
1202	<	if ((ev = e.val) == null)
1203	<	break;
1204	<	if (e.hash == h && (ek = e.key) != null &&
449	<	(k == ek || k.equals(ek))) {
450	<	if (tabAt(tab, i) == first) {
451	<	validated = true;
1197	>	try {
1198	>	if (tabAt(tab, i) == f) {
1199	>	validated = true;
1200	>	for (Node e = f, pred = null;;) {
1201	>	Object ek, ev;
1202	>	if ((e.hash & HASH_BITS) == h &&
1203	>	((ev = e.val) != null) &&
1204	>	((ek = e.key) == k || k.equals(ek))) {
1205		if (cv == null || cv == ev || cv.equals(ev)) {
1206		oldVal = ev;
1207		if ((e.val = v) == null) {
#	Line 460 | Line 1213 | public class ConcurrentHashMapV8<K, V>
1213		setTabAt(tab, i, en);
1214		}
1215		}
1216	+	break;
1217		}
1218	<	break;
1219	<	}
1220	<	pred = e;
467	<	if ((e = e.next) == null) {
468	<	if (tabAt(tab, i) == first)
469	<	validated = true;
470	<	break;
1218	>	pred = e;
1219	>	if ((e = e.next) == null)
1220	>	break;
1221		}
1222		}
1223	+	} finally {
1224	+	if (!f.casHash(fh | LOCKED, fh)) {
1225	+	f.hash = fh;
1226	+	synchronized (f) { f.notifyAll(); };
1227	+	}
1228		}
1229		if (validated) {
1230		if (deleted)
1231	<	counter.decrement();
1231	>	counter.add(-1L);
1232		break;
1233		}
1234		}
#	Line 481 | Line 1236 | public class ConcurrentHashMapV8<K, V>
1236		return oldVal;
1237		}
1238
1239	<	/** Implementation for computeIfAbsent and compute */
1240	<	@SuppressWarnings("unchecked")
1241	<	private final V internalCompute(K k,
1242	<	MappingFunction<? super K, ? extends V> f,
1243	<	boolean replace) {
1239	>	/*
1240	>	* Internal versions of the five insertion methods, each a
1241	>	* little more complicated than the last. All have
1242	>	* the same basic structure as the first (internalPut):
1243	>	*  1. If table uninitialized, create
1244	>	*  2. If bin empty, try to CAS new node
1245	>	*  3. If bin stale, use new table
1246	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1247	>	*  5. Lock and validate; if valid, scan and add or update
1248	>	*
1249	>	* The others interweave other checks and/or alternative actions:
1250	>	*  * Plain put checks for and performs resize after insertion.
1251	>	*  * putIfAbsent prescans for mapping without lock (and fails to add
1252	>	*    if present), which also makes pre-emptive resize checks worthwhile.
1253	>	*  * computeIfAbsent extends form used in putIfAbsent with additional
1254	>	*    mechanics to deal with, calls, potential exceptions and null
1255	>	*    returns from function call.
1256	>	*  * compute uses the same function-call mechanics, but without
1257	>	*    the prescans
1258	>	*  * putAll attempts to pre-allocate enough table space
1259	>	*    and more lazily performs count updates and checks.
1260	>	*
1261	>	* Someday when details settle down a bit more, it might be worth
1262	>	* some factoring to reduce sprawl.
1263	>	*/
1264	>
1265	>	/** Implementation for put */
1266	>	private final Object internalPut(Object k, Object v) {
1267		int h = spread(k.hashCode());
1268	<	V val = null;
1269	<	boolean added = false;
1270	<	boolean validated = false;
493	<	Node[] tab = table;
494	<	do {
495	<	Node e; int i;
1268	>	int count = 0;
1269	>	for (Node[] tab = table;;) {
1270	>	int i; Node f; int fh; Object fk;
1271		if (tab == null)
1272	<	tab = grow(0);
1273	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1274	<	Node node = new Node(h, k, null, null);
1275	<	synchronized(node) {
1276	<	if (casTabAt(tab, i, null, node)) {
1277	<	validated = true;
1278	<	try {
1279	<	val = f.map(k);
1280	<	if (val != null) {
1281	<	node.val = val;
1282	<	added = true;
1272	>	tab = initTable();
1273	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1274	>	if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1275	>	break;                   // no lock when adding to empty bin
1276	>	}
1277	>	else if ((fh = f.hash) == MOVED) {
1278	>	if ((fk = f.key) instanceof TreeBin) {
1279	>	TreeBin t = (TreeBin)fk;
1280	>	Object oldVal = null;
1281	>	t.acquire(0);
1282	>	try {
1283	>	if (tabAt(tab, i) == f) {
1284	>	count = 2;
1285	>	TreeNode p = t.putTreeNode(h, k, v);
1286	>	if (p != null) {
1287	>	oldVal = p.val;
1288	>	p.val = v;
1289	>	}
1290	>	}
1291	>	} finally {
1292	>	t.release(0);
1293	>	}
1294	>	if (count != 0) {
1295	>	if (oldVal != null)
1296	>	return oldVal;
1297	>	break;
1298	>	}
1299	>	}
1300	>	else
1301	>	tab = (Node[])fk;
1302	>	}
1303	>	else if ((fh & LOCKED) != 0) {
1304	>	checkForResize();
1305	>	f.tryAwaitLock(tab, i);
1306	>	}
1307	>	else if (f.casHash(fh, fh | LOCKED)) {
1308	>	Object oldVal = null;
1309	>	try {                        // needed in case equals() throws
1310	>	if (tabAt(tab, i) == f) {
1311	>	count = 1;
1312	>	for (Node e = f;; ++count) {
1313	>	Object ek, ev;
1314	>	if ((e.hash & HASH_BITS) == h &&
1315	>	(ev = e.val) != null &&
1316	>	((ek = e.key) == k || k.equals(ek))) {
1317	>	oldVal = ev;
1318	>	e.val = v;
1319	>	break;
1320	>	}
1321	>	Node last = e;
1322	>	if ((e = e.next) == null) {
1323	>	last.next = new Node(h, k, v, null);
1324	>	if (count >= TREE_THRESHOLD)
1325	>	replaceWithTreeBin(tab, i, k);
1326	>	break;
1327		}
509	–	} finally {
510	–	if (!added)
511	–	setTabAt(tab, i, null);
1328		}
1329		}
1330	+	} finally {                  // unlock and signal if needed
1331	+	if (!f.casHash(fh | LOCKED, fh)) {
1332	+	f.hash = fh;
1333	+	synchronized (f) { f.notifyAll(); };
1334	+	}
1335	+	}
1336	+	if (count != 0) {
1337	+	if (oldVal != null)
1338	+	return oldVal;
1339	+	if (tab.length <= 64)
1340	+	count = 2;
1341	+	break;
1342		}
1343		}
1344	<	else if (e.hash < 0)
1345	<	tab = (Node[])e.key;
1344	>	}
1345	>	counter.add(1L);
1346	>	if (count > 1)
1347	>	checkForResize();
1348	>	return null;
1349	>	}
1350	>
1351	>	/** Implementation for putIfAbsent */
1352	>	private final Object internalPutIfAbsent(Object k, Object v) {
1353	>	int h = spread(k.hashCode());
1354	>	int count = 0;
1355	>	for (Node[] tab = table;;) {
1356	>	int i; Node f; int fh; Object fk, fv;
1357	>	if (tab == null)
1358	>	tab = initTable();
1359	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1360	>	if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1361	>	break;
1362	>	}
1363	>	else if ((fh = f.hash) == MOVED) {
1364	>	if ((fk = f.key) instanceof TreeBin) {
1365	>	TreeBin t = (TreeBin)fk;
1366	>	Object oldVal = null;
1367	>	t.acquire(0);
1368	>	try {
1369	>	if (tabAt(tab, i) == f) {
1370	>	count = 2;
1371	>	TreeNode p = t.putTreeNode(h, k, v);
1372	>	if (p != null)
1373	>	oldVal = p.val;
1374	>	}
1375	>	} finally {
1376	>	t.release(0);
1377	>	}
1378	>	if (count != 0) {
1379	>	if (oldVal != null)
1380	>	return oldVal;
1381	>	break;
1382	>	}
1383	>	}
1384	>	else
1385	>	tab = (Node[])fk;
1386	>	}
1387	>	else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1388	>	((fk = f.key) == k || k.equals(fk)))
1389	>	return fv;
1390		else {
1391	<	boolean checkSize = false;
1392	<	synchronized(e) {
1393	<	Node first = e;
522	<	for (;;) {
1391	>	Node g = f.next;
1392	>	if (g != null) { // at least 2 nodes -- search and maybe resize
1393	>	for (Node e = g;;) {
1394		Object ek, ev;
1395	<	if ((ev = e.val) == null)
1395	>	if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1396	>	((ek = e.key) == k || k.equals(ek)))
1397	>	return ev;
1398	>	if ((e = e.next) == null) {
1399	>	checkForResize();
1400		break;
1401	<	if (e.hash == h && (ek = e.key) != null &&
1402	<	(k == ek || k.equals(ek))) {
1403	<	if (tabAt(tab, i) == first) {
1404	<	validated = true;
1405	<	if (replace && (ev = f.map(k)) != null)
1406	<	e.val = ev;
1407	<	val = (V)ev;
1401	>	}
1402	>	}
1403	>	}
1404	>	if (((fh = f.hash) & LOCKED) != 0) {
1405	>	checkForResize();
1406	>	f.tryAwaitLock(tab, i);
1407	>	}
1408	>	else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1409	>	Object oldVal = null;
1410	>	try {
1411	>	if (tabAt(tab, i) == f) {
1412	>	count = 1;
1413	>	for (Node e = f;; ++count) {
1414	>	Object ek, ev;
1415	>	if ((e.hash & HASH_BITS) == h &&
1416	>	(ev = e.val) != null &&
1417	>	((ek = e.key) == k || k.equals(ek))) {
1418	>	oldVal = ev;
1419	>	break;
1420	>	}
1421	>	Node last = e;
1422	>	if ((e = e.next) == null) {
1423	>	last.next = new Node(h, k, v, null);
1424	>	if (count >= TREE_THRESHOLD)
1425	>	replaceWithTreeBin(tab, i, k);
1426	>	break;
1427	>	}
1428	>	}
1429	>	}
1430	>	} finally {
1431	>	if (!f.casHash(fh | LOCKED, fh)) {
1432	>	f.hash = fh;
1433	>	synchronized (f) { f.notifyAll(); };
1434	>	}
1435	>	}
1436	>	if (count != 0) {
1437	>	if (oldVal != null)
1438	>	return oldVal;
1439	>	if (tab.length <= 64)
1440	>	count = 2;
1441	>	break;
1442	>	}
1443	>	}
1444	>	}
1445	>	}
1446	>	counter.add(1L);
1447	>	if (count > 1)
1448	>	checkForResize();
1449	>	return null;
1450	>	}
1451	>
1452	>	/** Implementation for computeIfAbsent */
1453	>	private final Object internalComputeIfAbsent(K k,
1454	>	MappingFunction<? super K, ?> mf) {
1455	>	int h = spread(k.hashCode());
1456	>	Object val = null;
1457	>	int count = 0;
1458	>	for (Node[] tab = table;;) {
1459	>	Node f; int i, fh; Object fk, fv;
1460	>	if (tab == null)
1461	>	tab = initTable();
1462	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1463	>	Node node = new Node(fh = h | LOCKED, k, null, null);
1464	>	if (casTabAt(tab, i, null, node)) {
1465	>	count = 1;
1466	>	try {
1467	>	if ((val = mf.map(k)) != null)
1468	>	node.val = val;
1469	>	} finally {
1470	>	if (val == null)
1471	>	setTabAt(tab, i, null);
1472	>	if (!node.casHash(fh, h)) {
1473	>	node.hash = h;
1474	>	synchronized (node) { node.notifyAll(); };
1475	>	}
1476	>	}
1477	>	}
1478	>	if (count != 0)
1479	>	break;
1480	>	}
1481	>	else if ((fh = f.hash) == MOVED) {
1482	>	if ((fk = f.key) instanceof TreeBin) {
1483	>	TreeBin t = (TreeBin)fk;
1484	>	boolean added = false;
1485	>	t.acquire(0);
1486	>	try {
1487	>	if (tabAt(tab, i) == f) {
1488	>	count = 1;
1489	>	TreeNode p = t.getTreeNode(h, k, t.root);
1490	>	if (p != null)
1491	>	val = p.val;
1492	>	else if ((val = mf.map(k)) != null) {
1493	>	added = true;
1494	>	count = 2;
1495	>	t.putTreeNode(h, k, val);
1496		}
534	–	break;
1497		}
1498	<	Node last = e;
1498	>	} finally {
1499	>	t.release(0);
1500	>	}
1501	>	if (count != 0) {
1502	>	if (!added)
1503	>	return val;
1504	>	break;
1505	>	}
1506	>	}
1507	>	else
1508	>	tab = (Node[])fk;
1509	>	}
1510	>	else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1511	>	((fk = f.key) == k || k.equals(fk)))
1512	>	return fv;
1513	>	else {
1514	>	Node g = f.next;
1515	>	if (g != null) {
1516	>	for (Node e = g;;) {
1517	>	Object ek, ev;
1518	>	if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1519	>	((ek = e.key) == k || k.equals(ek)))
1520	>	return ev;
1521		if ((e = e.next) == null) {
1522	<	if (tabAt(tab, i) == first) {
1523	<	validated = true;
1524	<	if ((val = f.map(k)) != null) {
1525	<	last.next = new Node(h, k, val, null);
1526	<	added = true;
1527	<	if (last != first || tab.length <= 64)
1528	<	checkSize = true;
1522	>	checkForResize();
1523	>	break;
1524	>	}
1525	>	}
1526	>	}
1527	>	if (((fh = f.hash) & LOCKED) != 0) {
1528	>	checkForResize();
1529	>	f.tryAwaitLock(tab, i);
1530	>	}
1531	>	else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1532	>	boolean added = false;
1533	>	try {
1534	>	if (tabAt(tab, i) == f) {
1535	>	count = 1;
1536	>	for (Node e = f;; ++count) {
1537	>	Object ek, ev;
1538	>	if ((e.hash & HASH_BITS) == h &&
1539	>	(ev = e.val) != null &&
1540	>	((ek = e.key) == k || k.equals(ek))) {
1541	>	val = ev;
1542	>	break;
1543	>	}
1544	>	Node last = e;
1545	>	if ((e = e.next) == null) {
1546	>	if ((val = mf.map(k)) != null) {
1547	>	added = true;
1548	>	last.next = new Node(h, k, val, null);
1549	>	if (count >= TREE_THRESHOLD)
1550	>	replaceWithTreeBin(tab, i, k);
1551	>	}
1552	>	break;
1553		}
1554		}
1555	<	break;
1555	>	}
1556	>	} finally {
1557	>	if (!f.casHash(fh | LOCKED, fh)) {
1558	>	f.hash = fh;
1559	>	synchronized (f) { f.notifyAll(); };
1560		}
1561		}
1562	+	if (count != 0) {
1563	+	if (!added)
1564	+	return val;
1565	+	if (tab.length <= 64)
1566	+	count = 2;
1567	+	break;
1568	+	}
1569		}
1570	<	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
1571	<	resizing == 0 && counter.sum() >= threshold)
1572	<	grow(0);
1573	<	}
1574	<	} while (!validated);
1575	<	if (added)
1576	<	counter.increment();
1570	>	}
1571	>	}
1572	>	if (val != null) {
1573	>	counter.add(1L);
1574	>	if (count > 1)
1575	>	checkForResize();
1576	>	}
1577		return val;
1578		}
1579
1580	<	/*
1581	<	* Reclassifies nodes in each bin to new table.  Because we are
1582	<	* using power-of-two expansion, the elements from each bin must
1583	<	* either stay at same index, or move with a power of two
1584	<	* offset. We eliminate unnecessary node creation by catching
1585	<	* cases where old nodes can be reused because their next fields
1586	<	* won't change.  Statistically, at the default threshold, only
1587	<	* about one-sixth of them need cloning when a table doubles. The
1588	<	* nodes they replace will be garbage collectable as soon as they
1589	<	* are no longer referenced by any reader thread that may be in
1590	<	* the midst of concurrently traversing table.
1591	<	*
1592	<	* Transfers are done from the bottom up to preserve iterator
1593	<	* traversability. On each step, the old bin is locked,
1594	<	* moved/copied, and then replaced with a forwarding node.
1595	<	*/
1596	<	private static final void transfer(Node[] tab, Node[] nextTab) {
1597	<	int n = tab.length;
1598	<	int mask = nextTab.length - 1;
1599	<	Node fwd = new Node(MOVED, nextTab, null, null);
1600	<	for (int i = n - 1; i >= 0; --i) {
1601	<	for (Node e;;) {
1602	<	if ((e = tabAt(tab, i)) == null) {
1603	<	if (casTabAt(tab, i, e, fwd))
1580	>	/** Implementation for compute */
1581	>	@SuppressWarnings("unchecked")
1582	>	private final Object internalCompute(K k,
1583	>	RemappingFunction<? super K, V> mf) {
1584	>	int h = spread(k.hashCode());
1585	>	Object val = null;
1586	>	int delta = 0;
1587	>	int count = 0;
1588	>	for (Node[] tab = table;;) {
1589	>	Node f; int i, fh; Object fk;
1590	>	if (tab == null)
1591	>	tab = initTable();
1592	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1593	>	Node node = new Node(fh = h | LOCKED, k, null, null);
1594	>	if (casTabAt(tab, i, null, node)) {
1595	>	try {
1596	>	count = 1;
1597	>	if ((val = mf.remap(k, null)) != null) {
1598	>	node.val = val;
1599	>	delta = 1;
1600	>	}
1601	>	} finally {
1602	>	if (delta == 0)
1603	>	setTabAt(tab, i, null);
1604	>	if (!node.casHash(fh, h)) {
1605	>	node.hash = h;
1606	>	synchronized (node) { node.notifyAll(); };
1607	>	}
1608	>	}
1609	>	}
1610	>	if (count != 0)
1611	>	break;
1612	>	}
1613	>	else if ((fh = f.hash) == MOVED) {
1614	>	if ((fk = f.key) instanceof TreeBin) {
1615	>	TreeBin t = (TreeBin)fk;
1616	>	t.acquire(0);
1617	>	try {
1618	>	if (tabAt(tab, i) == f) {
1619	>	count = 1;
1620	>	TreeNode p = t.getTreeNode(h, k, t.root);
1621	>	Object pv = (p == null) ? null : p.val;
1622	>	if ((val = mf.remap(k, (V)pv)) != null) {
1623	>	if (p != null)
1624	>	p.val = val;
1625	>	else {
1626	>	count = 2;
1627	>	delta = 1;
1628	>	t.putTreeNode(h, k, val);
1629	>	}
1630	>	}
1631	>	else if (p != null) {
1632	>	delta = -1;
1633	>	t.deleteTreeNode(p);
1634	>	}
1635	>	}
1636	>	} finally {
1637	>	t.release(0);
1638	>	}
1639	>	if (count != 0)
1640		break;
1641		}
1642	<	else {
1643	<	boolean validated = false;
1644	<	synchronized(e) {
1645	<	int idx = e.hash & mask;
1646	<	Node lastRun = e;
1647	<	for (Node p = e.next; p != null; p = p.next) {
1648	<	int j = p.hash & mask;
1649	<	if (j != idx) {
1650	<	idx = j;
1651	<	lastRun = p;
1642	>	else
1643	>	tab = (Node[])fk;
1644	>	}
1645	>	else if ((fh & LOCKED) != 0) {
1646	>	checkForResize();
1647	>	f.tryAwaitLock(tab, i);
1648	>	}
1649	>	else if (f.casHash(fh, fh | LOCKED)) {
1650	>	try {
1651	>	if (tabAt(tab, i) == f) {
1652	>	count = 1;
1653	>	for (Node e = f, pred = null;; ++count) {
1654	>	Object ek, ev;
1655	>	if ((e.hash & HASH_BITS) == h &&
1656	>	(ev = e.val) != null &&
1657	>	((ek = e.key) == k || k.equals(ek))) {
1658	>	val = mf.remap(k, (V)ev);
1659	>	if (val != null)
1660	>	e.val = val;
1661	>	else {
1662	>	delta = -1;
1663	>	Node en = e.next;
1664	>	if (pred != null)
1665	>	pred.next = en;
1666	>	else
1667	>	setTabAt(tab, i, en);
1668	>	}
1669	>	break;
1670	>	}
1671	>	pred = e;
1672	>	if ((e = e.next) == null) {
1673	>	if ((val = mf.remap(k, null)) != null) {
1674	>	pred.next = new Node(h, k, val, null);
1675	>	delta = 1;
1676	>	if (count >= TREE_THRESHOLD)
1677	>	replaceWithTreeBin(tab, i, k);
1678	>	}
1679	>	break;
1680		}
1681		}
1682	<	if (tabAt(tab, i) == e) {
1683	<	validated = true;
1684	<	relaxedSetTabAt(nextTab, idx, lastRun);
1685	<	for (Node p = e; p != lastRun; p = p.next) {
1686	<	int h = p.hash;
1687	<	int j = h & mask;
1688	<	Node r = relaxedTabAt(nextTab, j);
1689	<	relaxedSetTabAt(nextTab, j,
1690	<	new Node(h, p.key, p.val, r));
1682	>	}
1683	>	} finally {
1684	>	if (!f.casHash(fh | LOCKED, fh)) {
1685	>	f.hash = fh;
1686	>	synchronized (f) { f.notifyAll(); };
1687	>	}
1688	>	}
1689	>	if (count != 0) {
1690	>	if (tab.length <= 64)
1691	>	count = 2;
1692	>	break;
1693	>	}
1694	>	}
1695	>	}
1696	>	if (delta != 0) {
1697	>	counter.add((long)delta);
1698	>	if (count > 1)
1699	>	checkForResize();
1700	>	}
1701	>	return val;
1702	>	}
1703	>
1704	>	/** Implementation for putAll */
1705	>	private final void internalPutAll(Map<?, ?> m) {
1706	>	tryPresize(m.size());
1707	>	long delta = 0L;     // number of uncommitted additions
1708	>	boolean npe = false; // to throw exception on exit for nulls
1709	>	try {                // to clean up counts on other exceptions
1710	>	for (Map.Entry<?, ?> entry : m.entrySet()) {
1711	>	Object k, v;
1712	>	if (entry == null || (k = entry.getKey()) == null ||
1713	>	(v = entry.getValue()) == null) {
1714	>	npe = true;
1715	>	break;
1716	>	}
1717	>	int h = spread(k.hashCode());
1718	>	for (Node[] tab = table;;) {
1719	>	int i; Node f; int fh; Object fk;
1720	>	if (tab == null)
1721	>	tab = initTable();
1722	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1723	>	if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1724	>	++delta;
1725	>	break;
1726	>	}
1727	>	}
1728	>	else if ((fh = f.hash) == MOVED) {
1729	>	if ((fk = f.key) instanceof TreeBin) {
1730	>	TreeBin t = (TreeBin)fk;
1731	>	boolean validated = false;
1732	>	t.acquire(0);
1733	>	try {
1734	>	if (tabAt(tab, i) == f) {
1735	>	validated = true;
1736	>	TreeNode p = t.getTreeNode(h, k, t.root);
1737	>	if (p != null)
1738	>	p.val = v;
1739	>	else {
1740	>	t.putTreeNode(h, k, v);
1741	>	++delta;
1742	>	}
1743	>	}
1744	>	} finally {
1745	>	t.release(0);
1746		}
1747	<	setTabAt(tab, i, fwd);
1747	>	if (validated)
1748	>	break;
1749	>	}
1750	>	else
1751	>	tab = (Node[])fk;
1752	>	}
1753	>	else if ((fh & LOCKED) != 0) {
1754	>	counter.add(delta);
1755	>	delta = 0L;
1756	>	checkForResize();
1757	>	f.tryAwaitLock(tab, i);
1758	>	}
1759	>	else if (f.casHash(fh, fh | LOCKED)) {
1760	>	int count = 0;
1761	>	try {
1762	>	if (tabAt(tab, i) == f) {
1763	>	count = 1;
1764	>	for (Node e = f;; ++count) {
1765	>	Object ek, ev;
1766	>	if ((e.hash & HASH_BITS) == h &&
1767	>	(ev = e.val) != null &&
1768	>	((ek = e.key) == k || k.equals(ek))) {
1769	>	e.val = v;
1770	>	break;
1771	>	}
1772	>	Node last = e;
1773	>	if ((e = e.next) == null) {
1774	>	++delta;
1775	>	last.next = new Node(h, k, v, null);
1776	>	if (count >= TREE_THRESHOLD)
1777	>	replaceWithTreeBin(tab, i, k);
1778	>	break;
1779	>	}
1780	>	}
1781	>	}
1782	>	} finally {
1783	>	if (!f.casHash(fh | LOCKED, fh)) {
1784	>	f.hash = fh;
1785	>	synchronized (f) { f.notifyAll(); };
1786	>	}
1787	>	}
1788	>	if (count != 0) {
1789	>	if (count > 1) {
1790	>	counter.add(delta);
1791	>	delta = 0L;
1792	>	checkForResize();
1793	>	}
1794	>	break;
1795		}
1796		}
612	–	if (validated)
613	–	break;
1797		}
1798		}
1799	+	} finally {
1800	+	if (delta != 0)
1801	+	counter.add(delta);
1802		}
1803	+	if (npe)
1804	+	throw new NullPointerException();
1805	+	}
1806	+
1807	+	/* ---------------- Table Initialization and Resizing -------------- */
1808	+
1809	+	/**
1810	+	* Returns a power of two table size for the given desired capacity.
1811	+	* See Hackers Delight, sec 3.2
1812	+	*/
1813	+	private static final int tableSizeFor(int c) {
1814	+	int n = c - 1;
1815	+	n |= n >>> 1;
1816	+	n |= n >>> 2;
1817	+	n |= n >>> 4;
1818	+	n |= n >>> 8;
1819	+	n |= n >>> 16;
1820	+	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1821		}
1822
1823		/**
1824	<	* If not already resizing, initializes or creates next table and
1825	<	* transfers bins. Rechecks occupancy after a transfer to see if
1826	<	* another resize is already needed because resizings are lagging
1827	<	* additions.
1828	<	*
1829	<	* @param sizeHint overridden capacity target (nonzero only from putAll)
1830	<	* @return current table
1831	<	*/
1832	<	private final Node[] grow(int sizeHint) {
1833	<	if (resizing == 0 &&
1834	<	UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
1835	<	try {
1836	<	for (;;) {
633	<	int cap, n;
634	<	Node[] tab = table;
635	<	if (tab == null) {
636	<	int c = initCap;
637	<	if (c < sizeHint)
638	<	c = sizeHint;
639	<	if (c == DEFAULT_CAPACITY)
640	<	cap = c;
641	<	else if (c >= MAXIMUM_CAPACITY)
642	<	cap = MAXIMUM_CAPACITY;
643	<	else {
644	<	cap = MINIMUM_CAPACITY;
645	<	while (cap < c)
646	<	cap <<= 1;
647	<	}
1824	>	* Initializes table, using the size recorded in sizeCtl.
1825	>	*/
1826	>	private final Node[] initTable() {
1827	>	Node[] tab; int sc;
1828	>	while ((tab = table) == null) {
1829	>	if ((sc = sizeCtl) < 0)
1830	>	Thread.yield(); // lost initialization race; just spin
1831	>	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1832	>	try {
1833	>	if ((tab = table) == null) {
1834	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1835	>	tab = table = new Node[n];
1836	>	sc = n - (n >>> 2);
1837		}
1838	<	else if ((n = tab.length) < MAXIMUM_CAPACITY &&
1839	<	(sizeHint <= 0 || n < sizeHint))
651	<	cap = n << 1;
652	<	else
653	<	break;
654	<	threshold = (int)(cap * loadFactor) - THRESHOLD_OFFSET;
655	<	Node[] nextTab = new Node[cap];
656	<	if (tab != null)
657	<	transfer(tab, nextTab);
658	<	table = nextTab;
659	<	if (tab == null || cap >= MAXIMUM_CAPACITY ||
660	<	(sizeHint > 0 && cap >= sizeHint) ||
661	<	counter.sum() < threshold)
662	<	break;
1838	>	} finally {
1839	>	sizeCtl = sc;
1840		}
1841	<	} finally {
665	<	resizing = 0;
1841	>	break;
1842		}
1843		}
1844	<	else if (table == null)
669	<	Thread.yield(); // lost initialization race; just spin
670	<	return table;
1844	>	return tab;
1845		}
1846
1847		/**
1848	<	* Implementation for putAll and constructor with Map
1849	<	* argument. Tries to first override initial capacity or grow
1850	<	* based on map size to pre-allocate table space.
1848	>	* If table is too small and not already resizing, creates next
1849	>	* table and transfers bins.  Rechecks occupancy after a transfer
1850	>	* to see if another resize is already needed because resizings
1851	>	* are lagging additions.
1852		*/
1853	<	private final void internalPutAll(Map<? extends K, ? extends V> m) {
1854	<	int s = m.size();
1855	<	grow((s >= (MAXIMUM_CAPACITY >>> 1))? s : s + (s >>> 1));
1856	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
1857	<	Object k = e.getKey();
1858	<	Object v = e.getValue();
1859	<	if (k == null || v == null)
1860	<	throw new NullPointerException();
1861	<	internalPut(k, v, true);
1853	>	private final void checkForResize() {
1854	>	Node[] tab; int n, sc;
1855	>	while ((tab = table) != null &&
1856	>	(n = tab.length) < MAXIMUM_CAPACITY &&
1857	>	(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
1858	>	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1859	>	try {
1860	>	if (tab == table) {
1861	>	table = rebuild(tab);
1862	>	sc = (n << 1) - (n >>> 1);
1863	>	}
1864	>	} finally {
1865	>	sizeCtl = sc;
1866	>	}
1867		}
1868		}
1869
1870		/**
1871	<	* Implementation for clear. Steps through each bin, removing all nodes.
1871	>	* Tries to presize table to accommodate the given number of elements.
1872	>	*
1873	>	* @param size number of elements (doesn't need to be perfectly accurate)
1874		*/
1875	<	private final void internalClear() {
1876	<	long deletions = 0L;
1877	<	int i = 0;
1878	<	Node[] tab = table;
1879	<	while (tab != null && i < tab.length) {
1880	<	Node e = tabAt(tab, i);
1881	<	if (e == null)
1882	<	++i;
1883	<	else if (e.hash < 0)
1884	<	tab = (Node[])e.key;
1885	<	else {
1875	>	private final void tryPresize(int size) {
1876	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1877	>	tableSizeFor(size + (size >>> 1) + 1);
1878	>	int sc;
1879	>	while ((sc = sizeCtl) >= 0) {
1880	>	Node[] tab = table; int n;
1881	>	if (tab == null || (n = tab.length) == 0) {
1882	>	n = (sc > c) ? sc : c;
1883	>	if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1884	>	try {
1885	>	if (table == tab) {
1886	>	table = new Node[n];
1887	>	sc = n - (n >>> 2);
1888	>	}
1889	>	} finally {
1890	>	sizeCtl = sc;
1891	>	}
1892	>	}
1893	>	}
1894	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1895	>	break;
1896	>	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1897	>	try {
1898	>	if (table == tab) {
1899	>	table = rebuild(tab);
1900	>	sc = (n << 1) - (n >>> 1);
1901	>	}
1902	>	} finally {
1903	>	sizeCtl = sc;
1904	>	}
1905	>	}
1906	>	}
1907	>	}
1908	>
1909	>	/*
1910	>	* Moves and/or copies the nodes in each bin to new table. See
1911	>	* above for explanation.
1912	>	*
1913	>	* @return the new table
1914	>	*/
1915	>	private static final Node[] rebuild(Node[] tab) {
1916	>	int n = tab.length;
1917	>	Node[] nextTab = new Node[n << 1];
1918	>	Node fwd = new Node(MOVED, nextTab, null, null);
1919	>	int[] buffer = null;       // holds bins to revisit; null until needed
1920	>	Node rev = null;           // reverse forwarder; null until needed
1921	>	int nbuffered = 0;         // the number of bins in buffer list
1922	>	int bufferIndex = 0;       // buffer index of current buffered bin
1923	>	int bin = n - 1;           // current non-buffered bin or -1 if none
1924	>
1925	>	for (int i = bin;;) {      // start upwards sweep
1926	>	int fh; Node f;
1927	>	if ((f = tabAt(tab, i)) == null) {
1928	>	if (bin >= 0) {    // no lock needed (or available)
1929	>	if (!casTabAt(tab, i, f, fwd))
1930	>	continue;
1931	>	}
1932	>	else {             // transiently use a locked forwarding node
1933	>	Node g = new Node(MOVED|LOCKED, nextTab, null, null);
1934	>	if (!casTabAt(tab, i, f, g))
1935	>	continue;
1936	>	setTabAt(nextTab, i, null);
1937	>	setTabAt(nextTab, i + n, null);
1938	>	setTabAt(tab, i, fwd);
1939	>	if (!g.casHash(MOVED|LOCKED, MOVED)) {
1940	>	g.hash = MOVED;
1941	>	synchronized (g) { g.notifyAll(); }
1942	>	}
1943	>	}
1944	>	}
1945	>	else if ((fh = f.hash) == MOVED) {
1946	>	Object fk = f.key;
1947	>	if (fk instanceof TreeBin) {
1948	>	TreeBin t = (TreeBin)fk;
1949	>	boolean validated = false;
1950	>	t.acquire(0);
1951	>	try {
1952	>	if (tabAt(tab, i) == f) {
1953	>	validated = true;
1954	>	splitTreeBin(nextTab, i, t);
1955	>	setTabAt(tab, i, fwd);
1956	>	}
1957	>	} finally {
1958	>	t.release(0);
1959	>	}
1960	>	if (!validated)
1961	>	continue;
1962	>	}
1963	>	}
1964	>	else if ((fh & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
1965		boolean validated = false;
1966	<	synchronized(e) {
1967	<	if (tabAt(tab, i) == e) {
1966	>	try {              // split to lo and hi lists; copying as needed
1967	>	if (tabAt(tab, i) == f) {
1968		validated = true;
1969	<	do {
1970	<	if (e.val != null) {
710	<	e.val = null;
711	<	++deletions;
712	<	}
713	<	} while ((e = e.next) != null);
714	<	setTabAt(tab, i, null);
1969	>	splitBin(nextTab, i, f);
1970	>	setTabAt(tab, i, fwd);
1971		}
1972	<	}
1973	<	if (validated) {
1974	<	++i;
1975	<	if (deletions > THRESHOLD_OFFSET) { // bound lag in counts
720	<	counter.add(-deletions);
721	<	deletions = 0L;
1972	>	} finally {
1973	>	if (!f.casHash(fh | LOCKED, fh)) {
1974	>	f.hash = fh;
1975	>	synchronized (f) { f.notifyAll(); };
1976		}
1977		}
1978	+	if (!validated)
1979	+	continue;
1980		}
1981	+	else {
1982	+	if (buffer == null) // initialize buffer for revisits
1983	+	buffer = new int[TRANSFER_BUFFER_SIZE];
1984	+	if (bin < 0 && bufferIndex > 0) {
1985	+	int j = buffer[--bufferIndex];
1986	+	buffer[bufferIndex] = i;
1987	+	i = j;         // swap with another bin
1988	+	continue;
1989	+	}
1990	+	if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
1991	+	f.tryAwaitLock(tab, i);
1992	+	continue;      // no other options -- block
1993	+	}
1994	+	if (rev == null)   // initialize reverse-forwarder
1995	+	rev = new Node(MOVED, tab, null, null);
1996	+	if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
1997	+	continue;      // recheck before adding to list
1998	+	buffer[nbuffered++] = i;
1999	+	setTabAt(nextTab, i, rev);     // install place-holders
2000	+	setTabAt(nextTab, i + n, rev);
2001	+	}
2002	+
2003	+	if (bin > 0)
2004	+	i = --bin;
2005	+	else if (buffer != null && nbuffered > 0) {
2006	+	bin = -1;
2007	+	i = buffer[bufferIndex = --nbuffered];
2008	+	}
2009	+	else
2010	+	return nextTab;
2011		}
726	–	if (deletions != 0L)
727	–	counter.add(-deletions);
2012		}
2013
2014		/**
2015	<	* Base class for key, value, and entry iterators, plus internal
2016	<	* implementations of public traversal-based methods, to avoid
733	<	* duplicating traversal code.
2015	>	* Split a normal bin with list headed by e into lo and hi parts;
2016	>	* install in given table
2017		*/
2018	<	class HashIterator {
2019	<	private Node next;          // the next entry to return
2020	<	private Node[] tab;         // current table; updated if resized
2021	<	private Node lastReturned;  // the last entry returned, for remove
2022	<	private Object nextVal;     // cached value of next
2023	<	private int index;          // index of bin to use next
2024	<	private int baseIndex;      // current index of initial table
2025	<	private final int baseSize; // initial table size
2018	>	private static void splitBin(Node[] nextTab, int i, Node e) {
2019	>	int bit = nextTab.length >>> 1; // bit to split on
2020	>	int runBit = e.hash & bit;
2021	>	Node lastRun = e, lo = null, hi = null;
2022	>	for (Node p = e.next; p != null; p = p.next) {
2023	>	int b = p.hash & bit;
2024	>	if (b != runBit) {
2025	>	runBit = b;
2026	>	lastRun = p;
2027	>	}
2028	>	}
2029	>	if (runBit == 0)
2030	>	lo = lastRun;
2031	>	else
2032	>	hi = lastRun;
2033	>	for (Node p = e; p != lastRun; p = p.next) {
2034	>	int ph = p.hash & HASH_BITS;
2035	>	Object pk = p.key, pv = p.val;
2036	>	if ((ph & bit) == 0)
2037	>	lo = new Node(ph, pk, pv, lo);
2038	>	else
2039	>	hi = new Node(ph, pk, pv, hi);
2040	>	}
2041	>	setTabAt(nextTab, i, lo);
2042	>	setTabAt(nextTab, i + bit, hi);
2043	>	}
2044
2045	<	HashIterator() {
2046	<	Node[] t = tab = table;
2047	<	if (t == null)
2048	<	baseSize = 0;
2045	>	/**
2046	>	* Split a tree bin into lo and hi parts; install in given table
2047	>	*/
2048	>	private static void splitTreeBin(Node[] nextTab, int i, TreeBin t) {
2049	>	int bit = nextTab.length >>> 1;
2050	>	TreeBin lt = new TreeBin();
2051	>	TreeBin ht = new TreeBin();
2052	>	int lc = 0, hc = 0;
2053	>	for (Node e = t.first; e != null; e = e.next) {
2054	>	int h = e.hash & HASH_BITS;
2055	>	Object k = e.key, v = e.val;
2056	>	if ((h & bit) == 0) {
2057	>	++lc;
2058	>	lt.putTreeNode(h, k, v);
2059	>	}
2060		else {
2061	<	baseSize = t.length;
2062	<	advance(null);
2061	>	++hc;
2062	>	ht.putTreeNode(h, k, v);
2063		}
2064		}
2065	+	Node ln, hn; // throw away trees if too small
2066	+	if (lc <= (TREE_THRESHOLD >>> 1)) {
2067	+	ln = null;
2068	+	for (Node p = lt.first; p != null; p = p.next)
2069	+	ln = new Node(p.hash, p.key, p.val, ln);
2070	+	}
2071	+	else
2072	+	ln = new Node(MOVED, lt, null, null);
2073	+	setTabAt(nextTab, i, ln);
2074	+	if (hc <= (TREE_THRESHOLD >>> 1)) {
2075	+	hn = null;
2076	+	for (Node p = ht.first; p != null; p = p.next)
2077	+	hn = new Node(p.hash, p.key, p.val, hn);
2078	+	}
2079	+	else
2080	+	hn = new Node(MOVED, ht, null, null);
2081	+	setTabAt(nextTab, i + bit, hn);
2082	+	}
2083
2084	<	public final boolean hasNext()         { return next != null; }
2085	<	public final boolean hasMoreElements() { return next != null; }
2086	<
2087	<	/**
2088	<	* Advances next.  Normally, iteration proceeds bin-by-bin
2089	<	* traversing lists.  However, if the table has been resized,
2090	<	* then all future steps must traverse both the bin at the
2091	<	* current index as well as at (index + baseSize); and so on
2092	<	* for further resizings. To paranoically cope with potential
2093	<	* (improper) sharing of iterators across threads, table reads
2094	<	* are bounds-checked.
2095	<	*/
2096	<	final void advance(Node e) {
2097	<	for (;;) {
2098	<	Node[] t; int i; // for bounds checks
2099	<	if (e != null) {
2100	<	Object ek = e.key, ev = e.val;
2101	<	if (ev != null && ek != null) {
2102	<	nextVal = ev;
2103	<	next = e;
2104	<	break;
2084	>	/**
2085	>	* Implementation for clear. Steps through each bin, removing all
2086	>	* nodes.
2087	>	*/
2088	>	private final void internalClear() {
2089	>	long delta = 0L; // negative number of deletions
2090	>	int i = 0;
2091	>	Node[] tab = table;
2092	>	while (tab != null && i < tab.length) {
2093	>	int fh; Object fk;
2094	>	Node f = tabAt(tab, i);
2095	>	if (f == null)
2096	>	++i;
2097	>	else if ((fh = f.hash) == MOVED) {
2098	>	if ((fk = f.key) instanceof TreeBin) {
2099	>	TreeBin t = (TreeBin)fk;
2100	>	t.acquire(0);
2101	>	try {
2102	>	if (tabAt(tab, i) == f) {
2103	>	for (Node p = t.first; p != null; p = p.next) {
2104	>	p.val = null;
2105	>	--delta;
2106	>	}
2107	>	t.first = null;
2108	>	t.root = null;
2109	>	++i;
2110	>	}
2111	>	} finally {
2112	>	t.release(0);
2113		}
776	–	e = e.next;
2114		}
2115	<	else if (baseIndex < baseSize && (t = tab) != null &&
2116	<	t.length > (i = index) && i >= 0) {
2117	<	if ((e = tabAt(t, i)) != null && e.hash < 0) {
2118	<	tab = (Node[])e.key;
2119	<	e = null;
2115	>	else
2116	>	tab = (Node[])fk;
2117	>	}
2118	>	else if ((fh & LOCKED) != 0) {
2119	>	counter.add(delta); // opportunistically update count
2120	>	delta = 0L;
2121	>	f.tryAwaitLock(tab, i);
2122	>	}
2123	>	else if (f.casHash(fh, fh | LOCKED)) {
2124	>	try {
2125	>	if (tabAt(tab, i) == f) {
2126	>	for (Node e = f; e != null; e = e.next) {
2127	>	e.val = null;
2128	>	--delta;
2129	>	}
2130	>	setTabAt(tab, i, null);
2131	>	++i;
2132	>	}
2133	>	} finally {
2134	>	if (!f.casHash(fh | LOCKED, fh)) {
2135	>	f.hash = fh;
2136	>	synchronized (f) { f.notifyAll(); };
2137		}
784	–	else if (i + baseSize < t.length)
785	–	index += baseSize;    // visit forwarded upper slots
786	–	else
787	–	index = ++baseIndex;
788	–	}
789	–	else {
790	–	next = null;
791	–	break;
2138		}
2139		}
2140		}
2141	+	if (delta != 0)
2142	+	counter.add(delta);
2143	+	}
2144
2145	<	final Object nextKey() {
797	<	Node e = next;
798	<	if (e == null)
799	<	throw new NoSuchElementException();
800	<	Object k = e.key;
801	<	advance((lastReturned = e).next);
802	<	return k;
803	<	}
2145	>	/* ----------------Table Traversal -------------- */
2146
2147	<	final Object nextValue() {
2148	<	Node e = next;
2149	<	if (e == null)
2150	<	throw new NoSuchElementException();
2151	<	Object v = nextVal;
2152	<	advance((lastReturned = e).next);
2153	<	return v;
2147	>	/**
2148	>	* Encapsulates traversal for methods such as containsValue; also
2149	>	* serves as a base class for other iterators.
2150	>	*
2151	>	* At each step, the iterator snapshots the key ("nextKey") and
2152	>	* value ("nextVal") of a valid node (i.e., one that, at point of
2153	>	* snapshot, has a non-null user value). Because val fields can
2154	>	* change (including to null, indicating deletion), field nextVal
2155	>	* might not be accurate at point of use, but still maintains the
2156	>	* weak consistency property of holding a value that was once
2157	>	* valid.
2158	>	*
2159	>	* Internal traversals directly access these fields, as in:
2160	>	* {@code while (it.advance() != null) { process(it.nextKey); }}
2161	>	*
2162	>	* Exported iterators must track whether the iterator has advanced
2163	>	* (in hasNext vs next) (by setting/checking/nulling field
2164	>	* nextVal), and then extract key, value, or key-value pairs as
2165	>	* return values of next().
2166	>	*
2167	>	* The iterator visits once each still-valid node that was
2168	>	* reachable upon iterator construction. It might miss some that
2169	>	* were added to a bin after the bin was visited, which is OK wrt
2170	>	* consistency guarantees. Maintaining this property in the face
2171	>	* of possible ongoing resizes requires a fair amount of
2172	>	* bookkeeping state that is difficult to optimize away amidst
2173	>	* volatile accesses.  Even so, traversal maintains reasonable
2174	>	* throughput.
2175	>	*
2176	>	* Normally, iteration proceeds bin-by-bin traversing lists.
2177	>	* However, if the table has been resized, then all future steps
2178	>	* must traverse both the bin at the current index as well as at
2179	>	* (index + baseSize); and so on for further resizings. To
2180	>	* paranoically cope with potential sharing by users of iterators
2181	>	* across threads, iteration terminates if a bounds checks fails
2182	>	* for a table read.
2183	>	*/
2184	>	static class InternalIterator<K,V> {
2185	>	final ConcurrentHashMapV8<K, V> map;
2186	>	Node next;           // the next entry to use
2187	>	Node last;           // the last entry used
2188	>	Object nextKey;      // cached key field of next
2189	>	Object nextVal;      // cached val field of next
2190	>	Node[] tab;          // current table; updated if resized
2191	>	int index;           // index of bin to use next
2192	>	int baseIndex;       // current index of initial table
2193	>	int baseLimit;       // index bound for initial table
2194	>	final int baseSize;  // initial table size
2195	>
2196	>	/** Creates iterator for all entries in the table. */
2197	>	InternalIterator(ConcurrentHashMapV8<K, V> map) {
2198	>	this.tab = (this.map = map).table;
2199	>	baseLimit = baseSize = (tab == null) ? 0 : tab.length;
2200	>	}
2201	>
2202	>	/** Creates iterator for clone() and split() methods */
2203	>	InternalIterator(InternalIterator<K,V> it, boolean split) {
2204	>	this.map = it.map;
2205	>	this.tab = it.tab;
2206	>	this.baseSize = it.baseSize;
2207	>	int lo = it.baseIndex;
2208	>	int hi = this.baseLimit = it.baseLimit;
2209	>	this.index = this.baseIndex =
2210	>	(split) ? (it.baseLimit = (lo + hi + 1) >>> 1) : lo;
2211		}
2212
2213	<	final WriteThroughEntry nextEntry() {
2214	<	Node e = next;
2215	<	if (e == null)
2216	<	throw new NoSuchElementException();
2217	<	WriteThroughEntry entry =
2218	<	new WriteThroughEntry(e.key, nextVal);
2219	<	advance((lastReturned = e).next);
2220	<	return entry;
2213	>	/**
2214	>	* Advances next; returns nextVal or null if terminated
2215	>	* See above for explanation.
2216	>	*/
2217	>	final Object advance() {
2218	>	Node e = last = next;
2219	>	Object ev = null;
2220	>	outer: do {
2221	>	if (e != null)                  // advance past used/skipped node
2222	>	e = e.next;
2223	>	while (e == null) {             // get to next non-null bin
2224	>	Node[] t; int b, i, n; Object ek; // checks must use locals
2225	>	if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
2226	>	(t = tab) == null || i >= (n = t.length))
2227	>	break outer;
2228	>	else if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
2229	>	if ((ek = e.key) instanceof TreeBin)
2230	>	e = ((TreeBin)ek).first;
2231	>	else {
2232	>	tab = (Node[])ek;
2233	>	continue;           // restarts due to null val
2234	>	}
2235	>	}                           // visit upper slots if present
2236	>	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2237	>	}
2238	>	nextKey = e.key;
2239	>	} while ((ev = e.val) == null);    // skip deleted or special nodes
2240	>	next = e;
2241	>	return nextVal = ev;
2242		}
2243
2244		public final void remove() {
2245	<	if (lastReturned == null)
2245	>	if (nextVal == null)
2246	>	advance();
2247	>	Node e = last;
2248	>	if (e == null)
2249		throw new IllegalStateException();
2250	<	ConcurrentHashMapV8.this.remove(lastReturned.key);
2251	<	lastReturned = null;
829	<	}
830	<
831	<	/** Helper for serialization */
832	<	final void writeEntries(java.io.ObjectOutputStream s)
833	<	throws java.io.IOException {
834	<	Node e;
835	<	while ((e = next) != null) {
836	<	s.writeObject(e.key);
837	<	s.writeObject(nextVal);
838	<	advance(e.next);
839	<	}
2250	>	last = null;
2251	>	map.remove(e.key);
2252		}
2253
2254	<	/** Helper for containsValue */
2255	<	final boolean containsVal(Object value) {
844	<	if (value != null) {
845	<	Node e;
846	<	while ((e = next) != null) {
847	<	Object v = nextVal;
848	<	if (value == v || value.equals(v))
849	<	return true;
850	<	advance(e.next);
851	<	}
852	<	}
853	<	return false;
2254	>	public final boolean hasNext() {
2255	>	return nextVal != null || advance() != null;
2256		}
2257
2258	<	/** Helper for Map.hashCode */
857	<	final int mapHashCode() {
858	<	int h = 0;
859	<	Node e;
860	<	while ((e = next) != null) {
861	<	h += e.key.hashCode() ^ nextVal.hashCode();
862	<	advance(e.next);
863	<	}
864	<	return h;
865	<	}
866	<
867	<	/** Helper for Map.toString */
868	<	final String mapToString() {
869	<	Node e = next;
870	<	if (e == null)
871	<	return "{}";
872	<	StringBuilder sb = new StringBuilder();
873	<	sb.append('{');
874	<	for (;;) {
875	<	sb.append(e.key   == this ? "(this Map)" : e.key);
876	<	sb.append('=');
877	<	sb.append(nextVal == this ? "(this Map)" : nextVal);
878	<	advance(e.next);
879	<	if ((e = next) != null)
880	<	sb.append(',').append(' ');
881	<	else
882	<	return sb.append('}').toString();
883	<	}
884	<	}
2258	>	public final boolean hasMoreElements() { return hasNext(); }
2259		}
2260
2261		/* ---------------- Public operations -------------- */
2262
2263		/**
2264	<	* Creates a new, empty map with the specified initial
891	<	* capacity, load factor and concurrency level.
892	<	*
893	<	* @param initialCapacity the initial capacity. The implementation
894	<	* performs internal sizing to accommodate this many elements.
895	<	* @param loadFactor  the load factor threshold, used to control resizing.
896	<	* Resizing may be performed when the average number of elements per
897	<	* bin exceeds this threshold.
898	<	* @param concurrencyLevel the estimated number of concurrently
899	<	* updating threads. The implementation may use this value as
900	<	* a sizing hint.
901	<	* @throws IllegalArgumentException if the initial capacity is
902	<	* negative or the load factor or concurrencyLevel are
903	<	* nonpositive.
2264	>	* Creates a new, empty map with the default initial table size (16),
2265		*/
2266	<	public ConcurrentHashMapV8(int initialCapacity,
906	<	float loadFactor, int concurrencyLevel) {
907	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
908	<	throw new IllegalArgumentException();
909	<	this.initCap = initialCapacity;
910	<	this.loadFactor = loadFactor;
2266	>	public ConcurrentHashMapV8() {
2267		this.counter = new LongAdder();
2268		}
2269
2270		/**
2271	<	* Creates a new, empty map with the specified initial capacity
2272	<	* and load factor and with the default concurrencyLevel (16).
2271	>	* Creates a new, empty map with an initial table size
2272	>	* accommodating the specified number of elements without the need
2273	>	* to dynamically resize.
2274		*
2275		* @param initialCapacity The implementation performs internal
2276		* sizing to accommodate this many elements.
920	–	* @param loadFactor  the load factor threshold, used to control resizing.
921	–	* Resizing may be performed when the average number of elements per
922	–	* bin exceeds this threshold.
2277		* @throws IllegalArgumentException if the initial capacity of
2278	<	* elements is negative or the load factor is nonpositive
925	<	*
926	<	* @since 1.6
2278	>	* elements is negative
2279		*/
2280	<	public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
2281	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2280	>	public ConcurrentHashMapV8(int initialCapacity) {
2281	>	if (initialCapacity < 0)
2282	>	throw new IllegalArgumentException();
2283	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2284	>	MAXIMUM_CAPACITY :
2285	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2286	>	this.counter = new LongAdder();
2287	>	this.sizeCtl = cap;
2288		}
2289
2290		/**
2291	<	* Creates a new, empty map with the specified initial capacity,
934	<	* and with default load factor (0.75) and concurrencyLevel (16).
2291	>	* Creates a new map with the same mappings as the given map.
2292		*
2293	<	* @param initialCapacity the initial capacity. The implementation
937	<	* performs internal sizing to accommodate this many elements.
938	<	* @throws IllegalArgumentException if the initial capacity of
939	<	* elements is negative.
2293	>	* @param m the map
2294		*/
2295	<	public ConcurrentHashMapV8(int initialCapacity) {
2296	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2295	>	public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2296	>	this.counter = new LongAdder();
2297	>	this.sizeCtl = DEFAULT_CAPACITY;
2298	>	internalPutAll(m);
2299		}
2300
2301		/**
2302	<	* Creates a new, empty map with a default initial capacity (16),
2303	<	* load factor (0.75) and concurrencyLevel (16).
2302	>	* Creates a new, empty map with an initial table size based on
2303	>	* the given number of elements ({@code initialCapacity}) and
2304	>	* initial table density ({@code loadFactor}).
2305	>	*
2306	>	* @param initialCapacity the initial capacity. The implementation
2307	>	* performs internal sizing to accommodate this many elements,
2308	>	* given the specified load factor.
2309	>	* @param loadFactor the load factor (table density) for
2310	>	* establishing the initial table size
2311	>	* @throws IllegalArgumentException if the initial capacity of
2312	>	* elements is negative or the load factor is nonpositive
2313	>	*
2314	>	* @since 1.6
2315		*/
2316	<	public ConcurrentHashMapV8() {
2317	<	this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2316	>	public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
2317	>	this(initialCapacity, loadFactor, 1);
2318		}
2319
2320		/**
2321	<	* Creates a new map with the same mappings as the given map.
2322	<	* The map is created with a capacity of 1.5 times the number
2323	<	* of mappings in the given map or 16 (whichever is greater),
2324	<	* and a default load factor (0.75) and concurrencyLevel (16).
2321	>	* Creates a new, empty map with an initial table size based on
2322	>	* the given number of elements ({@code initialCapacity}), table
2323	>	* density ({@code loadFactor}), and number of concurrently
2324	>	* updating threads ({@code concurrencyLevel}).
2325		*
2326	<	* @param m the map
2326	>	* @param initialCapacity the initial capacity. The implementation
2327	>	* performs internal sizing to accommodate this many elements,
2328	>	* given the specified load factor.
2329	>	* @param loadFactor the load factor (table density) for
2330	>	* establishing the initial table size
2331	>	* @param concurrencyLevel the estimated number of concurrently
2332	>	* updating threads. The implementation may use this value as
2333	>	* a sizing hint.
2334	>	* @throws IllegalArgumentException if the initial capacity is
2335	>	* negative or the load factor or concurrencyLevel are
2336	>	* nonpositive
2337		*/
2338	<	public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2339	<	this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2340	<	if (m == null)
2341	<	throw new NullPointerException();
2342	<	internalPutAll(m);
2338	>	public ConcurrentHashMapV8(int initialCapacity,
2339	>	float loadFactor, int concurrencyLevel) {
2340	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2341	>	throw new IllegalArgumentException();
2342	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2343	>	initialCapacity = concurrencyLevel;   // as estimated threads
2344	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2345	>	int cap = ((size >= (long)MAXIMUM_CAPACITY) ?
2346	>	MAXIMUM_CAPACITY: tableSizeFor((int)size));
2347	>	this.counter = new LongAdder();
2348	>	this.sizeCtl = cap;
2349		}
2350
2351		/**
2352	<	* Returns {@code true} if this map contains no key-value mappings.
970	<	*
971	<	* @return {@code true} if this map contains no key-value mappings
2352	>	* {@inheritDoc}
2353		*/
2354		public boolean isEmpty() {
2355		return counter.sum() <= 0L; // ignore transient negative values
2356		}
2357
2358		/**
2359	<	* Returns the number of key-value mappings in this map.  If the
979	<	* map contains more than {@code Integer.MAX_VALUE} elements, returns
980	<	* {@code Integer.MAX_VALUE}.
981	<	*
982	<	* @return the number of key-value mappings in this map
2359	>	* {@inheritDoc}
2360		*/
2361		public int size() {
2362		long n = counter.sum();
2363	<	return n <= 0L? 0 : n >= Integer.MAX_VALUE ? Integer.MAX_VALUE : (int)n;
2363	>	return ((n < 0L) ? 0 :
2364	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2365	>	(int)n);
2366	>	}
2367	>
2368	>	final long longSize() { // accurate version of size needed for views
2369	>	long n = counter.sum();
2370	>	return (n < 0L) ? 0L : n;
2371		}
2372
2373		/**
#	Line 1010 | Line 2394 | public class ConcurrentHashMapV8<K, V>
2394		* @param  key   possible key
2395		* @return {@code true} if and only if the specified object
2396		*         is a key in this table, as determined by the
2397	<	*         {@code equals} method; {@code false} otherwise.
2397	>	*         {@code equals} method; {@code false} otherwise
2398		* @throws NullPointerException if the specified key is null
2399		*/
2400		public boolean containsKey(Object key) {
#	Line 1021 | Line 2405 | public class ConcurrentHashMapV8<K, V>
2405
2406		/**
2407		* Returns {@code true} if this map maps one or more keys to the
2408	<	* specified value. Note: This method requires a full internal
2409	<	* traversal of the hash table, and so is much slower than
1026	<	* method {@code containsKey}.
2408	>	* specified value. Note: This method may require a full traversal
2409	>	* of the map, and is much slower than method {@code containsKey}.
2410		*
2411		* @param value value whose presence in this map is to be tested
2412		* @return {@code true} if this map maps one or more keys to the
#	Line 1033 | Line 2416 | public class ConcurrentHashMapV8<K, V>
2416		public boolean containsValue(Object value) {
2417		if (value == null)
2418		throw new NullPointerException();
2419	<	return new HashIterator().containsVal(value);
2419	>	Object v;
2420	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2421	>	while ((v = it.advance()) != null) {
2422	>	if (v == value || value.equals(v))
2423	>	return true;
2424	>	}
2425	>	return false;
2426		}
2427
2428		/**
#	Line 1072 | Line 2461 | public class ConcurrentHashMapV8<K, V>
2461		public V put(K key, V value) {
2462		if (key == null || value == null)
2463		throw new NullPointerException();
2464	<	return (V)internalPut(key, value, true);
2464	>	return (V)internalPut(key, value);
2465		}
2466
2467		/**
#	Line 1086 | Line 2475 | public class ConcurrentHashMapV8<K, V>
2475		public V putIfAbsent(K key, V value) {
2476		if (key == null || value == null)
2477		throw new NullPointerException();
2478	<	return (V)internalPut(key, value, false);
2478	>	return (V)internalPutIfAbsent(key, value);
2479		}
2480
2481		/**
#	Line 1097 | Line 2486 | public class ConcurrentHashMapV8<K, V>
2486		* @param m mappings to be stored in this map
2487		*/
2488		public void putAll(Map<? extends K, ? extends V> m) {
1100	–	if (m == null)
1101	–	throw new NullPointerException();
2489		internalPutAll(m);
2490		}
2491
2492		/**
2493		* If the specified key is not already associated with a value,
2494	<	* computes its value using the given mappingFunction, and if
2495	<	* non-null, enters it into the map.  This is equivalent to
2496	<	*
2497	<	* <pre>
2498	<	*   if (map.containsKey(key))
2499	<	*       return map.get(key);
2500	<	*   value = mappingFunction.map(key);
2501	<	*   if (value != null)
2502	<	*      map.put(key, value);
2503	<	*   return value;
2504	<	* </pre>
2505	<	*
2506	<	* except that the action is performed atomically.  Some attempted
2507	<	* operations on this map by other threads may be blocked while
2508	<	* computation is in progress, so the computation should be short
2509	<	* and simple, and must not attempt to update any other mappings
2510	<	* of this Map. The most common usage is to construct a new object
2511	<	* serving as an initial mapped value, or memoized result.
2494	>	* computes its value using the given mappingFunction and enters
2495	>	* it into the map unless null.  This is equivalent to
2496	>	* <pre> {@code
2497	>	* if (map.containsKey(key))
2498	>	*   return map.get(key);
2499	>	* value = mappingFunction.map(key);
2500	>	* if (value != null)
2501	>	*   map.put(key, value);
2502	>	* return value;}</pre>
2503	>	*
2504	>	* except that the action is performed atomically.  If the
2505	>	* function returns {@code null} no mapping is recorded. If the
2506	>	* function itself throws an (unchecked) exception, the exception
2507	>	* is rethrown to its caller, and no mapping is recorded.  Some
2508	>	* attempted update operations on this map by other threads may be
2509	>	* blocked while computation is in progress, so the computation
2510	>	* should be short and simple, and must not attempt to update any
2511	>	* other mappings of this Map. The most appropriate usage is to
2512	>	* construct a new object serving as an initial mapped value, or
2513	>	* memoized result, as in:
2514	>	*
2515	>	*  <pre> {@code
2516	>	* map.computeIfAbsent(key, new MappingFunction<K, V>() {
2517	>	*   public V map(K k) { return new Value(f(k)); }});}</pre>
2518		*
2519		* @param key key with which the specified value is to be associated
2520		* @param mappingFunction the function to compute a value
2521		* @return the current (existing or computed) value associated with
2522	<	*         the specified key, or {@code null} if the computation
1130	<	*         returned {@code null}.
2522	>	*         the specified key, or null if the computed value is null.
2523		* @throws NullPointerException if the specified key or mappingFunction
2524	<	*         is null,
2524	>	*         is null
2525	>	* @throws IllegalStateException if the computation detectably
2526	>	*         attempts a recursive update to this map that would
2527	>	*         otherwise never complete
2528		* @throws RuntimeException or Error if the mappingFunction does so,
2529	<	*         in which case the mapping is left unestablished.
2529	>	*         in which case the mapping is left unestablished
2530		*/
2531	+	@SuppressWarnings("unchecked")
2532		public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2533		if (key == null || mappingFunction == null)
2534		throw new NullPointerException();
2535	<	return internalCompute(key, mappingFunction, false);
2535	>	return (V)internalComputeIfAbsent(key, mappingFunction);
2536		}
2537
2538		/**
2539	<	* Computes the value associated with he given key using the given
2540	<	* mappingFunction, and if non-null, enters it into the map.  This
2541	<	* is equivalent to
2542	<	*
2543	<	* <pre>
1148	<	*   value = mappingFunction.map(key);
2539	>	* Computes a new mapping value given a key and
2540	>	* its current mapped value (or {@code null} if there is no current
2541	>	* mapping). This is equivalent to
2542	>	*  <pre> {@code
2543	>	*   value = remappingFunction.remap(key, map.get(key));
2544		*   if (value != null)
2545	<	*      map.put(key, value);
2545	>	*     map.put(key, value);
2546		*   else
2547	<	*      return map.get(key);
2548	<	* </pre>
2547	>	*     map.remove(key);
2548	>	* }</pre>
2549		*
2550	<	* except that the action is performed atomically.  Some attempted
2551	<	* operations on this map by other threads may be blocked while
2552	<	* computation is in progress, so the computation should be short
2553	<	* and simple, and must not attempt to update any other mappings
2554	<	* of this Map.
2550	>	* except that the action is performed atomically.  If the
2551	>	* function returns {@code null}, the mapping is removed.  If the
2552	>	* function itself throws an (unchecked) exception, the exception
2553	>	* is rethrown to its caller, and the current mapping is left
2554	>	* unchanged.  Some attempted update operations on this map by
2555	>	* other threads may be blocked while computation is in progress,
2556	>	* so the computation should be short and simple, and must not
2557	>	* attempt to update any other mappings of this Map. For example,
2558	>	* to either create or append new messages to a value mapping:
2559	>	*
2560	>	* <pre> {@code
2561	>	* Map<Key, String> map = ...;
2562	>	* final String msg = ...;
2563	>	* map.compute(key, new RemappingFunction<Key, String>() {
2564	>	*   public String remap(Key k, String v) {
2565	>	*    return (v == null) ? msg : v + msg;});}}</pre>
2566		*
2567		* @param key key with which the specified value is to be associated
2568	<	* @param mappingFunction the function to compute a value
2569	<	* @return the current value associated with
2570	<	*         the specified key, or {@code null} if the computation
2571	<	*         returned {@code null} and the value was not otherwise present.
2572	<	* @throws NullPointerException if the specified key or mappingFunction
2573	<	*         is null,
2574	<	* @throws RuntimeException or Error if the mappingFunction does so,
2575	<	*         in which case the mapping is unchanged.
2568	>	* @param remappingFunction the function to compute a value
2569	>	* @return the new value associated with
2570	>	*         the specified key, or null if none.
2571	>	* @throws NullPointerException if the specified key or remappingFunction
2572	>	*         is null
2573	>	* @throws IllegalStateException if the computation detectably
2574	>	*         attempts a recursive update to this map that would
2575	>	*         otherwise never complete
2576	>	* @throws RuntimeException or Error if the remappingFunction does so,
2577	>	*         in which case the mapping is unchanged
2578		*/
2579	<	public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2580	<	if (key == null || mappingFunction == null)
2579	>	@SuppressWarnings("unchecked")
2580	>	public V compute(K key, RemappingFunction<? super K, V> remappingFunction) {
2581	>	if (key == null || remappingFunction == null)
2582		throw new NullPointerException();
2583	<	return internalCompute(key, mappingFunction, true);
2583	>	return (V)internalCompute(key, remappingFunction);
2584		}
2585
2586		/**
#	Line 1252 | Line 2661 | public class ConcurrentHashMapV8<K, V>
2661		* reflect any modifications subsequent to construction.
2662		*/
2663		public Set<K> keySet() {
2664	<	Set<K> ks = keySet;
2665	<	return (ks != null) ? ks : (keySet = new KeySet());
2664	>	KeySet<K,V> ks = keySet;
2665	>	return (ks != null) ? ks : (keySet = new KeySet<K,V>(this));
2666		}
2667
2668		/**
#	Line 1273 | Line 2682 | public class ConcurrentHashMapV8<K, V>
2682		* reflect any modifications subsequent to construction.
2683		*/
2684		public Collection<V> values() {
2685	<	Collection<V> vs = values;
2686	<	return (vs != null) ? vs : (values = new Values());
2685	>	Values<K,V> vs = values;
2686	>	return (vs != null) ? vs : (values = new Values<K,V>(this));
2687		}
2688
2689		/**
#	Line 1294 | Line 2703 | public class ConcurrentHashMapV8<K, V>
2703		* reflect any modifications subsequent to construction.
2704		*/
2705		public Set<Map.Entry<K,V>> entrySet() {
2706	<	Set<Map.Entry<K,V>> es = entrySet;
2707	<	return (es != null) ? es : (entrySet = new EntrySet());
2706	>	EntrySet<K,V> es = entrySet;
2707	>	return (es != null) ? es : (entrySet = new EntrySet<K,V>(this));
2708		}
2709
2710		/**
#	Line 1305 | Line 2714 | public class ConcurrentHashMapV8<K, V>
2714		* @see #keySet()
2715		*/
2716		public Enumeration<K> keys() {
2717	<	return new KeyIterator();
2717	>	return new KeyIterator<K,V>(this);
2718		}
2719
2720		/**
#	Line 1315 | Line 2724 | public class ConcurrentHashMapV8<K, V>
2724		* @see #values()
2725		*/
2726		public Enumeration<V> elements() {
2727	<	return new ValueIterator();
2727	>	return new ValueIterator<K,V>(this);
2728	>	}
2729	>
2730	>	/**
2731	>	* Returns a partionable iterator of the keys in this map.
2732	>	*
2733	>	* @return a partionable iterator of the keys in this map
2734	>	*/
2735	>	public Spliterator<K> keySpliterator() {
2736	>	return new KeyIterator<K,V>(this);
2737	>	}
2738	>
2739	>	/**
2740	>	* Returns a partionable iterator of the values in this map.
2741	>	*
2742	>	* @return a partionable iterator of the values in this map
2743	>	*/
2744	>	public Spliterator<V> valueSpliterator() {
2745	>	return new ValueIterator<K,V>(this);
2746	>	}
2747	>
2748	>	/**
2749	>	* Returns a partionable iterator of the entries in this map.
2750	>	*
2751	>	* @return a partionable iterator of the entries in this map
2752	>	*/
2753	>	public Spliterator<Map.Entry<K,V>> entrySpliterator() {
2754	>	return new EntryIterator<K,V>(this);
2755		}
2756
2757		/**
#	Line 1326 | Line 2762 | public class ConcurrentHashMapV8<K, V>
2762		* @return the hash code value for this map
2763		*/
2764		public int hashCode() {
2765	<	return new HashIterator().mapHashCode();
2765	>	int h = 0;
2766	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2767	>	Object v;
2768	>	while ((v = it.advance()) != null) {
2769	>	h += it.nextKey.hashCode() ^ v.hashCode();
2770	>	}
2771	>	return h;
2772		}
2773
2774		/**
#	Line 1341 | Line 2783 | public class ConcurrentHashMapV8<K, V>
2783		* @return a string representation of this map
2784		*/
2785		public String toString() {
2786	<	return new HashIterator().mapToString();
2786	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2787	>	StringBuilder sb = new StringBuilder();
2788	>	sb.append('{');
2789	>	Object v;
2790	>	if ((v = it.advance()) != null) {
2791	>	for (;;) {
2792	>	Object k = it.nextKey;
2793	>	sb.append(k == this ? "(this Map)" : k);
2794	>	sb.append('=');
2795	>	sb.append(v == this ? "(this Map)" : v);
2796	>	if ((v = it.advance()) == null)
2797	>	break;
2798	>	sb.append(',').append(' ');
2799	>	}
2800	>	}
2801	>	return sb.append('}').toString();
2802		}
2803
2804		/**
#	Line 1355 | Line 2812 | public class ConcurrentHashMapV8<K, V>
2812		* @return {@code true} if the specified object is equal to this map
2813		*/
2814		public boolean equals(Object o) {
2815	<	if (o == this)
2816	<	return true;
2817	<	if (!(o instanceof Map))
2818	<	return false;
2819	<	Map<?,?> m = (Map<?,?>) o;
2820	<	try {
2821	<	for (Map.Entry<K,V> e : this.entrySet())
2822	<	if (! e.getValue().equals(m.get(e.getKey())))
2815	>	if (o != this) {
2816	>	if (!(o instanceof Map))
2817	>	return false;
2818	>	Map<?,?> m = (Map<?,?>) o;
2819	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2820	>	Object val;
2821	>	while ((val = it.advance()) != null) {
2822	>	Object v = m.get(it.nextKey);
2823	>	if (v == null || (v != val && !v.equals(val)))
2824		return false;
2825	+	}
2826		for (Map.Entry<?,?> e : m.entrySet()) {
2827	<	Object k = e.getKey();
2828	<	Object v = e.getValue();
2829	<	if (k == null || v == null || !v.equals(get(k)))
2827	>	Object mk, mv, v;
2828	>	if ((mk = e.getKey()) == null ||
2829	>	(mv = e.getValue()) == null ||
2830	>	(v = internalGet(mk)) == null ||
2831	>	(mv != v && !mv.equals(v)))
2832		return false;
2833		}
2834	<	return true;
2835	<	} catch (ClassCastException unused) {
2836	<	return false;
2837	<	} catch (NullPointerException unused) {
2838	<	return false;
2834	>	}
2835	>	return true;
2836	>	}
2837	>
2838	>	/* ----------------Iterators -------------- */
2839	>
2840	>	static final class KeyIterator<K,V> extends InternalIterator<K,V>
2841	>	implements Spliterator<K>, Enumeration<K> {
2842	>	KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2843	>	KeyIterator(InternalIterator<K,V> it, boolean split) {
2844	>	super(it, split);
2845	>	}
2846	>	public KeyIterator<K,V> split() {
2847	>	if (last != null || (next != null && nextVal == null))
2848	>	throw new IllegalStateException();
2849	>	return new KeyIterator<K,V>(this, true);
2850	>	}
2851	>	public KeyIterator<K,V> clone() {
2852	>	if (last != null || (next != null && nextVal == null))
2853	>	throw new IllegalStateException();
2854	>	return new KeyIterator<K,V>(this, false);
2855	>	}
2856	>
2857	>	@SuppressWarnings("unchecked")
2858	>	public final K next() {
2859	>	if (nextVal == null && advance() == null)
2860	>	throw new NoSuchElementException();
2861	>	Object k = nextKey;
2862	>	nextVal = null;
2863	>	return (K) k;
2864	>	}
2865	>
2866	>	public final K nextElement() { return next(); }
2867	>	}
2868	>
2869	>	static final class ValueIterator<K,V> extends InternalIterator<K,V>
2870	>	implements Spliterator<V>, Enumeration<V> {
2871	>	ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2872	>	ValueIterator(InternalIterator<K,V> it, boolean split) {
2873	>	super(it, split);
2874	>	}
2875	>	public ValueIterator<K,V> split() {
2876	>	if (last != null || (next != null && nextVal == null))
2877	>	throw new IllegalStateException();
2878	>	return new ValueIterator<K,V>(this, true);
2879	>	}
2880	>
2881	>	public ValueIterator<K,V> clone() {
2882	>	if (last != null || (next != null && nextVal == null))
2883	>	throw new IllegalStateException();
2884	>	return new ValueIterator<K,V>(this, false);
2885	>	}
2886	>
2887	>	@SuppressWarnings("unchecked")
2888	>	public final V next() {
2889	>	Object v;
2890	>	if ((v = nextVal) == null && (v = advance()) == null)
2891	>	throw new NoSuchElementException();
2892	>	nextVal = null;
2893	>	return (V) v;
2894	>	}
2895	>
2896	>	public final V nextElement() { return next(); }
2897	>	}
2898	>
2899	>	static final class EntryIterator<K,V> extends InternalIterator<K,V>
2900	>	implements Spliterator<Map.Entry<K,V>> {
2901	>	EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2902	>	EntryIterator(InternalIterator<K,V> it, boolean split) {
2903	>	super(it, split);
2904	>	}
2905	>	public EntryIterator<K,V> split() {
2906	>	if (last != null || (next != null && nextVal == null))
2907	>	throw new IllegalStateException();
2908	>	return new EntryIterator<K,V>(this, true);
2909	>	}
2910	>	public EntryIterator<K,V> clone() {
2911	>	if (last != null || (next != null && nextVal == null))
2912	>	throw new IllegalStateException();
2913	>	return new EntryIterator<K,V>(this, false);
2914	>	}
2915	>
2916	>	@SuppressWarnings("unchecked")
2917	>	public final Map.Entry<K,V> next() {
2918	>	Object v;
2919	>	if ((v = nextVal) == null && (v = advance()) == null)
2920	>	throw new NoSuchElementException();
2921	>	Object k = nextKey;
2922	>	nextVal = null;
2923	>	return new MapEntry<K,V>((K)k, (V)v, map);
2924		}
2925		}
2926
2927		/**
2928	<	* Custom Entry class used by EntryIterator.next(), that relays
1383	<	* setValue changes to the underlying map.
2928	>	* Exported Entry for iterators
2929		*/
2930	<	final class WriteThroughEntry extends AbstractMap.SimpleEntry<K,V> {
2931	<	@SuppressWarnings("unchecked")
2932	<	WriteThroughEntry(Object k, Object v) {
2933	<	super((K)k, (V)v);
2930	>	static final class MapEntry<K,V> implements Map.Entry<K, V> {
2931	>	final K key; // non-null
2932	>	V val;       // non-null
2933	>	final ConcurrentHashMapV8<K, V> map;
2934	>	MapEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
2935	>	this.key = key;
2936	>	this.val = val;
2937	>	this.map = map;
2938	>	}
2939	>	public final K getKey()       { return key; }
2940	>	public final V getValue()     { return val; }
2941	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
2942	>	public final String toString(){ return key + "=" + val; }
2943	>
2944	>	public final boolean equals(Object o) {
2945	>	Object k, v; Map.Entry<?,?> e;
2946	>	return ((o instanceof Map.Entry) &&
2947	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
2948	>	(v = e.getValue()) != null &&
2949	>	(k == key || k.equals(key)) &&
2950	>	(v == val || v.equals(val)));
2951		}
2952
2953		/**
2954		* Sets our entry's value and writes through to the map. The
2955	<	* value to return is somewhat arbitrary here. Since a
2956	<	* WriteThroughEntry does not necessarily track asynchronous
2957	<	* changes, the most recent "previous" value could be
2958	<	* different from what we return (or could even have been
2959	<	* removed in which case the put will re-establish). We do not
1398	<	* and cannot guarantee more.
2955	>	* value to return is somewhat arbitrary here. Since a we do
2956	>	* not necessarily track asynchronous changes, the most recent
2957	>	* "previous" value could be different from what we return (or
2958	>	* could even have been removed in which case the put will
2959	>	* re-establish). We do not and cannot guarantee more.
2960		*/
2961	<	public V setValue(V value) {
2961	>	public final V setValue(V value) {
2962		if (value == null) throw new NullPointerException();
2963	<	V v = super.setValue(value);
2964	<	ConcurrentHashMapV8.this.put(getKey(), value);
2963	>	V v = val;
2964	>	val = value;
2965	>	map.put(key, value);
2966		return v;
2967		}
2968		}
2969
2970	<	final class KeyIterator extends HashIterator
1409	<	implements Iterator<K>, Enumeration<K> {
1410	<	@SuppressWarnings("unchecked")
1411	<	public final K next()        { return (K)super.nextKey(); }
1412	<	@SuppressWarnings("unchecked")
1413	<	public final K nextElement() { return (K)super.nextKey(); }
1414	<	}
1415	<
1416	<	final class ValueIterator extends HashIterator
1417	<	implements Iterator<V>, Enumeration<V> {
1418	<	@SuppressWarnings("unchecked")
1419	<	public final V next()        { return (V)super.nextValue(); }
1420	<	@SuppressWarnings("unchecked")
1421	<	public final V nextElement() { return (V)super.nextValue(); }
1422	<	}
2970	>	/* ----------------Views -------------- */
2971
2972	<	final class EntryIterator extends HashIterator
2973	<	implements Iterator<Entry<K,V>> {
2974	<	public final Map.Entry<K,V> next() { return super.nextEntry(); }
2975	<	}
2972	>	/**
2973	>	* Base class for views.
2974	>	*/
2975	>	static abstract class MapView<K, V> {
2976	>	final ConcurrentHashMapV8<K, V> map;
2977	>	MapView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
2978	>	public final int size()                 { return map.size(); }
2979	>	public final boolean isEmpty()          { return map.isEmpty(); }
2980	>	public final void clear()               { map.clear(); }
2981	>
2982	>	// implementations below rely on concrete classes supplying these
2983	>	abstract public Iterator<?> iterator();
2984	>	abstract public boolean contains(Object o);
2985	>	abstract public boolean remove(Object o);
2986	>
2987	>	private static final String oomeMsg = "Required array size too large";
2988	>
2989	>	public final Object[] toArray() {
2990	>	long sz = map.longSize();
2991	>	if (sz > (long)(MAX_ARRAY_SIZE))
2992	>	throw new OutOfMemoryError(oomeMsg);
2993	>	int n = (int)sz;
2994	>	Object[] r = new Object[n];
2995	>	int i = 0;
2996	>	Iterator<?> it = iterator();
2997	>	while (it.hasNext()) {
2998	>	if (i == n) {
2999	>	if (n >= MAX_ARRAY_SIZE)
3000	>	throw new OutOfMemoryError(oomeMsg);
3001	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3002	>	n = MAX_ARRAY_SIZE;
3003	>	else
3004	>	n += (n >>> 1) + 1;
3005	>	r = Arrays.copyOf(r, n);
3006	>	}
3007	>	r[i++] = it.next();
3008	>	}
3009	>	return (i == n) ? r : Arrays.copyOf(r, i);
3010	>	}
3011
3012	<	final class KeySet extends AbstractSet<K> {
3013	<	public int size() {
3014	<	return ConcurrentHashMapV8.this.size();
3012	>	@SuppressWarnings("unchecked")
3013	>	public final <T> T[] toArray(T[] a) {
3014	>	long sz = map.longSize();
3015	>	if (sz > (long)(MAX_ARRAY_SIZE))
3016	>	throw new OutOfMemoryError(oomeMsg);
3017	>	int m = (int)sz;
3018	>	T[] r = (a.length >= m) ? a :
3019	>	(T[])java.lang.reflect.Array
3020	>	.newInstance(a.getClass().getComponentType(), m);
3021	>	int n = r.length;
3022	>	int i = 0;
3023	>	Iterator<?> it = iterator();
3024	>	while (it.hasNext()) {
3025	>	if (i == n) {
3026	>	if (n >= MAX_ARRAY_SIZE)
3027	>	throw new OutOfMemoryError(oomeMsg);
3028	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3029	>	n = MAX_ARRAY_SIZE;
3030	>	else
3031	>	n += (n >>> 1) + 1;
3032	>	r = Arrays.copyOf(r, n);
3033	>	}
3034	>	r[i++] = (T)it.next();
3035	>	}
3036	>	if (a == r && i < n) {
3037	>	r[i] = null; // null-terminate
3038	>	return r;
3039	>	}
3040	>	return (i == n) ? r : Arrays.copyOf(r, i);
3041		}
3042	<	public boolean isEmpty() {
3043	<	return ConcurrentHashMapV8.this.isEmpty();
3042	>
3043	>	public final int hashCode() {
3044	>	int h = 0;
3045	>	for (Iterator<?> it = iterator(); it.hasNext();)
3046	>	h += it.next().hashCode();
3047	>	return h;
3048		}
3049	<	public void clear() {
3050	<	ConcurrentHashMapV8.this.clear();
3049	>
3050	>	public final String toString() {
3051	>	StringBuilder sb = new StringBuilder();
3052	>	sb.append('[');
3053	>	Iterator<?> it = iterator();
3054	>	if (it.hasNext()) {
3055	>	for (;;) {
3056	>	Object e = it.next();
3057	>	sb.append(e == this ? "(this Collection)" : e);
3058	>	if (!it.hasNext())
3059	>	break;
3060	>	sb.append(',').append(' ');
3061	>	}
3062	>	}
3063	>	return sb.append(']').toString();
3064		}
3065	<	public Iterator<K> iterator() {
3066	<	return new KeyIterator();
3065	>
3066	>	public final boolean containsAll(Collection<?> c) {
3067	>	if (c != this) {
3068	>	for (Iterator<?> it = c.iterator(); it.hasNext();) {
3069	>	Object e = it.next();
3070	>	if (e == null || !contains(e))
3071	>	return false;
3072	>	}
3073	>	}
3074	>	return true;
3075		}
3076	<	public boolean contains(Object o) {
3077	<	return ConcurrentHashMapV8.this.containsKey(o);
3076	>
3077	>	public final boolean removeAll(Collection<?> c) {
3078	>	boolean modified = false;
3079	>	for (Iterator<?> it = iterator(); it.hasNext();) {
3080	>	if (c.contains(it.next())) {
3081	>	it.remove();
3082	>	modified = true;
3083	>	}
3084	>	}
3085	>	return modified;
3086		}
3087	<	public boolean remove(Object o) {
3088	<	return ConcurrentHashMapV8.this.remove(o) != null;
3087	>
3088	>	public final boolean retainAll(Collection<?> c) {
3089	>	boolean modified = false;
3090	>	for (Iterator<?> it = iterator(); it.hasNext();) {
3091	>	if (!c.contains(it.next())) {
3092	>	it.remove();
3093	>	modified = true;
3094	>	}
3095	>	}
3096	>	return modified;
3097		}
3098	+
3099		}
3100
3101	<	final class Values extends AbstractCollection<V> {
3102	<	public int size() {
3103	<	return ConcurrentHashMapV8.this.size();
3104	<	}
3105	<	public boolean isEmpty() {
3106	<	return ConcurrentHashMapV8.this.isEmpty();
3101	>	static final class KeySet<K,V> extends MapView<K,V> implements Set<K> {
3102	>	KeySet(ConcurrentHashMapV8<K, V> map)   { super(map); }
3103	>	public final boolean contains(Object o) { return map.containsKey(o); }
3104	>	public final boolean remove(Object o)   { return map.remove(o) != null; }
3105	>	public final Iterator<K> iterator() {
3106	>	return new KeyIterator<K,V>(map);
3107		}
3108	<	public void clear() {
3109	<	ConcurrentHashMapV8.this.clear();
3108	>	public final boolean add(K e) {
3109	>	throw new UnsupportedOperationException();
3110		}
3111	<	public Iterator<V> iterator() {
3112	<	return new ValueIterator();
3111	>	public final boolean addAll(Collection<? extends K> c) {
3112	>	throw new UnsupportedOperationException();
3113		}
3114	<	public boolean contains(Object o) {
3115	<	return ConcurrentHashMapV8.this.containsValue(o);
3114	>	public boolean equals(Object o) {
3115	>	Set<?> c;
3116	>	return ((o instanceof Set) &&
3117	>	((c = (Set<?>)o) == this ||
3118	>	(containsAll(c) && c.containsAll(this))));
3119		}
3120		}
3121
3122	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
3123	<	public int size() {
3124	<	return ConcurrentHashMapV8.this.size();
3122	>	static final class Values<K,V> extends MapView<K,V>
3123	>	implements Collection<V> {
3124	>	Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
3125	>	public final boolean contains(Object o) { return map.containsValue(o); }
3126	>	public final boolean remove(Object o) {
3127	>	if (o != null) {
3128	>	Iterator<V> it = new ValueIterator<K,V>(map);
3129	>	while (it.hasNext()) {
3130	>	if (o.equals(it.next())) {
3131	>	it.remove();
3132	>	return true;
3133	>	}
3134	>	}
3135	>	}
3136	>	return false;
3137		}
3138	<	public boolean isEmpty() {
3139	<	return ConcurrentHashMapV8.this.isEmpty();
3138	>	public final Iterator<V> iterator() {
3139	>	return new ValueIterator<K,V>(map);
3140		}
3141	<	public void clear() {
3142	<	ConcurrentHashMapV8.this.clear();
3141	>	public final boolean add(V e) {
3142	>	throw new UnsupportedOperationException();
3143		}
3144	<	public Iterator<Map.Entry<K,V>> iterator() {
3145	<	return new EntryIterator();
3144	>	public final boolean addAll(Collection<? extends V> c) {
3145	>	throw new UnsupportedOperationException();
3146		}
3147	<	public boolean contains(Object o) {
3148	<	if (!(o instanceof Map.Entry))
3149	<	return false;
3150	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3151	<	V v = ConcurrentHashMapV8.this.get(e.getKey());
3152	<	return v != null && v.equals(e.getValue());
3153	<	}
3154	<	public boolean remove(Object o) {
3155	<	if (!(o instanceof Map.Entry))
3156	<	return false;
3157	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3158	<	return ConcurrentHashMapV8.this.remove(e.getKey(), e.getValue());
3147	>	}
3148	>
3149	>	static final class EntrySet<K,V> extends MapView<K,V>
3150	>	implements Set<Map.Entry<K,V>> {
3151	>	EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
3152	>	public final boolean contains(Object o) {
3153	>	Object k, v, r; Map.Entry<?,?> e;
3154	>	return ((o instanceof Map.Entry) &&
3155	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3156	>	(r = map.get(k)) != null &&
3157	>	(v = e.getValue()) != null &&
3158	>	(v == r || v.equals(r)));
3159	>	}
3160	>	public final boolean remove(Object o) {
3161	>	Object k, v; Map.Entry<?,?> e;
3162	>	return ((o instanceof Map.Entry) &&
3163	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3164	>	(v = e.getValue()) != null &&
3165	>	map.remove(k, v));
3166	>	}
3167	>	public final Iterator<Map.Entry<K,V>> iterator() {
3168	>	return new EntryIterator<K,V>(map);
3169	>	}
3170	>	public final boolean add(Entry<K,V> e) {
3171	>	throw new UnsupportedOperationException();
3172	>	}
3173	>	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
3174	>	throw new UnsupportedOperationException();
3175	>	}
3176	>	public boolean equals(Object o) {
3177	>	Set<?> c;
3178	>	return ((o instanceof Set) &&
3179	>	((c = (Set<?>)o) == this ||
3180	>	(containsAll(c) && c.containsAll(this))));
3181		}
3182		}
3183
3184		/* ---------------- Serialization Support -------------- */
3185
3186		/**
3187	<	* Helper class used in previous version, declared for the sake of
3188	<	* serialization compatibility
3187	>	* Stripped-down version of helper class used in previous version,
3188	>	* declared for the sake of serialization compatibility
3189		*/
3190	<	static class Segment<K,V> extends java.util.concurrent.locks.ReentrantLock
1503	<	implements Serializable {
3190	>	static class Segment<K,V> implements Serializable {
3191		private static final long serialVersionUID = 2249069246763182397L;
3192		final float loadFactor;
3193		Segment(float lf) { this.loadFactor = lf; }
#	Line 1522 | Line 3209 | public class ConcurrentHashMapV8<K, V>
3209		segments = (Segment<K,V>[])
3210		new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3211		for (int i = 0; i < segments.length; ++i)
3212	<	segments[i] = new Segment<K,V>(loadFactor);
3212	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
3213		}
3214		s.defaultWriteObject();
3215	<	new HashIterator().writeEntries(s);
3215	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
3216	>	Object v;
3217	>	while ((v = it.advance()) != null) {
3218	>	s.writeObject(it.nextKey);
3219	>	s.writeObject(v);
3220	>	}
3221		s.writeObject(null);
3222		s.writeObject(null);
3223		segments = null; // throw away
3224		}
3225
3226		/**
3227	<	* Reconstitutes the  instance from a
1536	<	* stream (i.e., deserializes it).
3227	>	* Reconstitutes the instance from a stream (that is, deserializes it).
3228		* @param s the stream
3229		*/
3230		@SuppressWarnings("unchecked")
3231		private void readObject(java.io.ObjectInputStream s)
3232		throws java.io.IOException, ClassNotFoundException {
3233		s.defaultReadObject();
1543	–	// find load factor in a segment, if one exists
1544	–	if (segments != null && segments.length != 0)
1545	–	this.loadFactor = segments[0].loadFactor;
1546	–	else
1547	–	this.loadFactor = DEFAULT_LOAD_FACTOR;
1548	–	this.initCap = DEFAULT_CAPACITY;
1549	–	LongAdder ct = new LongAdder(); // force final field write
1550	–	UNSAFE.putObjectVolatile(this, counterOffset, ct);
3234		this.segments = null; // unneeded
3235	+	// initialize transient final field
3236	+	UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
3237
3238	<	// Read the keys and values, and put the mappings in the table
3238	>	// Create all nodes, then place in table once size is known
3239	>	long size = 0L;
3240	>	Node p = null;
3241		for (;;) {
3242	<	K key = (K) s.readObject();
3243	<	V value = (V) s.readObject();
3244	<	if (key == null)
3242	>	K k = (K) s.readObject();
3243	>	V v = (V) s.readObject();
3244	>	if (k != null && v != null) {
3245	>	int h = spread(k.hashCode());
3246	>	p = new Node(h, k, v, p);
3247	>	++size;
3248	>	}
3249	>	else
3250		break;
3251	<	put(key, value);
3251	>	}
3252	>	if (p != null) {
3253	>	boolean init = false;
3254	>	int n;
3255	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3256	>	n = MAXIMUM_CAPACITY;
3257	>	else {
3258	>	int sz = (int)size;
3259	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
3260	>	}
3261	>	int sc = sizeCtl;
3262	>	boolean collide = false;
3263	>	if (n > sc &&
3264	>	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
3265	>	try {
3266	>	if (table == null) {
3267	>	init = true;
3268	>	Node[] tab = new Node[n];
3269	>	int mask = n - 1;
3270	>	while (p != null) {
3271	>	int j = p.hash & mask;
3272	>	Node next = p.next;
3273	>	Node q = p.next = tabAt(tab, j);
3274	>	setTabAt(tab, j, p);
3275	>	if (!collide && q != null && q.hash == p.hash)
3276	>	collide = true;
3277	>	p = next;
3278	>	}
3279	>	table = tab;
3280	>	counter.add(size);
3281	>	sc = n - (n >>> 2);
3282	>	}
3283	>	} finally {
3284	>	sizeCtl = sc;
3285	>	}
3286	>	if (collide) { // rescan and convert to TreeBins
3287	>	Node[] tab = table;
3288	>	for (int i = 0; i < tab.length; ++i) {
3289	>	int c = 0;
3290	>	for (Node e = tabAt(tab, i); e != null; e = e.next) {
3291	>	if (++c > TREE_THRESHOLD &&
3292	>	(e.key instanceof Comparable)) {
3293	>	replaceWithTreeBin(tab, i, e.key);
3294	>	break;
3295	>	}
3296	>	}
3297	>	}
3298	>	}
3299	>	}
3300	>	if (!init) { // Can only happen if unsafely published.
3301	>	while (p != null) {
3302	>	internalPut(p.key, p.val);
3303	>	p = p.next;
3304	>	}
3305	>	}
3306		}
3307		}
3308
3309		// Unsafe mechanics
3310		private static final sun.misc.Unsafe UNSAFE;
3311		private static final long counterOffset;
3312	<	private static final long resizingOffset;
3312	>	private static final long sizeCtlOffset;
3313		private static final long ABASE;
3314		private static final int ASHIFT;
3315
#	Line 1574 | Line 3320 | public class ConcurrentHashMapV8<K, V>
3320		Class<?> k = ConcurrentHashMapV8.class;
3321		counterOffset = UNSAFE.objectFieldOffset
3322		(k.getDeclaredField("counter"));
3323	<	resizingOffset = UNSAFE.objectFieldOffset
3324	<	(k.getDeclaredField("resizing"));
3323	>	sizeCtlOffset = UNSAFE.objectFieldOffset
3324	>	(k.getDeclaredField("sizeCtl"));
3325		Class<?> sc = Node[].class;
3326		ABASE = UNSAFE.arrayBaseOffset(sc);
3327		ss = UNSAFE.arrayIndexScale(sc);

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