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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.16 by dl, Fri Sep 9 13:02:01 2011 UTC vs.
Revision 1.46 by dl, Thu Jul 5 18:05:28 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 54 | Line 58 | import java.io.Serializable;
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. There may be
62	<	* much variance around this average as mappings are added and
63	<	* removed, but overall, this maintains a commonly accepted time/space
64	<	* tradeoff for hash tables.  However, resizing this or any other kind
65	<	* of hash table may be a relatively slow operation. When possible, it
66	<	* is a good idea to provide a size estimate as an optional {@code
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
#	Line 68 | Line 73 | import java.io.Serializable;
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
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
#	Line 95 | 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} if there is no mapping. This is a place-holder
100	<	* 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
105	<	* mapping. If this function throws an (unchecked) exception,
106	<	* the exception is rethrown to its caller, and no mapping is
107	<	* recorded.  Because this function is invoked within
108	<	* atomicity control, the computation should be short and
109	<	* simple. The most common usage is to construct a new object
110	<	* 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 also
149	+	* 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		/*
201		* Overview:
202		*
203		* The primary design goal of this hash table is to maintain
204		* concurrent readability (typically method get(), but also
205		* iterators and related methods) while minimizing update
206	<	* contention.
206	>	* contention. Secondary goals are to keep space consumption about
207	>	* the same or better than java.util.HashMap, and to support high
208	>	* initial insertion rates on an empty table by many threads.
209		*
210		* Each key-value mapping is held in a Node.  Because Node fields
211		* can contain special values, they are defined using plain Object
#	Line 129 | Line 213 | public class ConcurrentHashMapV8<K, V>
213		* work off Object types. And similarly, so do the internal
214		* methods of auxiliary iterator and view classes.  All public
215		* generic typed methods relay in/out of these internal methods,
216	<	* supplying null-checks and casts as needed.
216	>	* supplying null-checks and casts as needed. This also allows
217	>	* many of the public methods to be factored into a smaller number
218	>	* of internal methods (although sadly not so for the five
219	>	* variants of put-related operations). The validation-based
220	>	* approach explained below leads to a lot of code sprawl because
221	>	* retry-control precludes factoring into smaller methods.
222		*
223		* The table is lazily initialized to a power-of-two size upon the
224	<	* first insertion.  Each bin in the table contains a list of
225	<	* Nodes (most often, zero or one Node).  Table accesses require
226	<	* volatile/atomic reads, writes, and CASes.  Because there is no
227	<	* other way to arrange this without adding further indirections,
228	<	* we use intrinsics (sun.misc.Unsafe) operations.  The lists of
229	<	* nodes within bins are always accurately traversable under
230	<	* volatile reads, so long as lookups check hash code and
231	<	* non-nullness of value before checking key equality. (All valid
232	<	* hash codes are nonnegative. Negative values are reserved for
233	<	* special forwarding nodes; see below.)
224	>	* first insertion.  Each bin in the table normally contains a
225	>	* list of Nodes (most often, the list has only zero or one Node).
226	>	* Table accesses require volatile/atomic reads, writes, and
227	>	* CASes.  Because there is no other way to arrange this without
228	>	* adding further indirections, we use intrinsics
229	>	* (sun.misc.Unsafe) operations.  The lists of nodes within bins
230	>	* are always accurately traversable under volatile reads, so long
231	>	* as lookups check hash code and non-nullness of value before
232	>	* checking key equality.
233	>	*
234	>	* We use the top two bits of Node hash fields for control
235	>	* purposes -- they are available anyway because of addressing
236	>	* constraints.  As explained further below, these top bits are
237	>	* used as follows:
238	>	*  00 - Normal
239	>	*  01 - Locked
240	>	*  11 - Locked and may have a thread waiting for lock
241	>	*  10 - Node is a forwarding node
242	>	*
243	>	* The lower 30 bits of each Node's hash field contain a
244	>	* transformation of the key's hash code, except for forwarding
245	>	* nodes, for which the lower bits are zero (and so always have
246	>	* hash field == MOVED).
247		*
248	<	* Insertion (via put or putIfAbsent) of the first node in an
248	>	* Insertion (via put or its variants) of the first node in an
249		* empty bin is performed by just CASing it to the bin.  This is
250	<	* on average by far the most common case for put operations.
251	<	* Other update operations (insert, delete, and replace) require
252	<	* locks.  We do not want to waste the space required to associate
253	<	* a distinct lock object with each bin, so instead use the first
254	<	* node of a bin list itself as a lock, using plain "synchronized"
255	<	* locks. These save space and we can live with block-structured
256	<	* lock/unlock operations. Using the first node of a list as a
257	<	* lock does not by itself suffice though: When a node is locked,
258	<	* any update must first validate that it is still the first node,
259	<	* and retry if not. Because new nodes are always appended to
260	<	* lists, once a node is first in a bin, it remains first until
261	<	* deleted or the bin becomes invalidated.  However, operations
262	<	* that only conditionally update can and sometimes do inspect
263	<	* nodes until the point of update. This is a converse of sorts to
264	<	* the lazy locking technique described by Herlihy & Shavit.
250	>	* by far the most common case for put operations under most
251	>	* key/hash distributions.  Other update operations (insert,
252	>	* delete, and replace) require locks.  We do not want to waste
253	>	* the space required to associate a distinct lock object with
254	>	* each bin, so instead use the first node of a bin list itself as
255	>	* a lock. Blocking support for these locks relies on the builtin
256	>	* "synchronized" monitors.  However, we also need a tryLock
257	>	* construction, so we overlay these by using bits of the Node
258	>	* hash field for lock control (see above), and so normally use
259	>	* builtin monitors only for blocking and signalling using
260	>	* wait/notifyAll constructions. See Node.tryAwaitLock.
261	>	*
262	>	* Using the first node of a list as a lock does not by itself
263	>	* suffice though: When a node is locked, any update must first
264	>	* validate that it is still the first node after locking it, and
265	>	* retry if not. Because new nodes are always appended to lists,
266	>	* once a node is first in a bin, it remains first until deleted
267	>	* or the bin becomes invalidated (upon resizing).  However,
268	>	* operations that only conditionally update may inspect nodes
269	>	* until the point of update. This is a converse of sorts to the
270	>	* lazy locking technique described by Herlihy & Shavit.
271		*
272	<	* The main disadvantage of this approach is that most update
272	>	* The main disadvantage of per-bin locks is that other update
273		* operations on other nodes in a bin list protected by the same
274		* lock can stall, for example when user equals() or mapping
275	<	* functions take a long time.  However, statistically, this is
276	<	* not a common enough problem to outweigh the time/space overhead
277	<	* of alternatives: Under random hash codes, the frequency of
170	<	* nodes in bins follows a Poisson distribution
275	>	* functions take a long time.  However, statistically, under
276	>	* random hash codes, this is not a common problem.  Ideally, the
277	>	* frequency of nodes in bins follows a Poisson distribution
278		* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
279		* parameter of about 0.5 on average, given the resizing threshold
280		* of 0.75, although with a large variance because of resizing
281		* granularity. Ignoring variance, the expected occurrences of
282		* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
283	<	* first few values are:
283	>	* first values are:
284		*
285	<	* 0:    0.607
286	<	* 1:    0.303
287	<	* 2:    0.076
288	<	* 3:    0.012
289	<	* more: 0.002
285	>	* 0:    0.60653066
286	>	* 1:    0.30326533
287	>	* 2:    0.07581633
288	>	* 3:    0.01263606
289	>	* 4:    0.00157952
290	>	* 5:    0.00015795
291	>	* 6:    0.00001316
292	>	* 7:    0.00000094
293	>	* 8:    0.00000006
294	>	* more: less than 1 in ten million
295		*
296		* Lock contention probability for two threads accessing distinct
297	<	* elements is roughly 1 / (8 * #elements).  Function "spread"
298	<	* performs hashCode randomization that improves the likelihood
299	<	* that these assumptions hold unless users define exactly the
300	<	* same value for too many hashCodes.
301	<	*
302	<	* The table is resized when occupancy exceeds a threshold.  Only
303	<	* a single thread performs the resize (using field "resizing", to
304	<	* arrange exclusion), but the table otherwise remains usable for
305	<	* reads and updates. Resizing proceeds by transferring bins, one
306	<	* by one, from the table to the next table.  Upon transfer, the
307	<	* old table bin contains only a special forwarding node (with
308	<	* negative hash field) that contains the next table as its
309	<	* key. On encountering a forwarding node, access and update
310	<	* operations restart, using the new table. To ensure concurrent
311	<	* readability of traversals, transfers must proceed from the last
312	<	* bin (table.length - 1) up towards the first.  Upon seeing a
313	<	* forwarding node, traversals (see class InternalIterator)
314	<	* arrange to move to the new table for the rest of the traversal
315	<	* without revisiting nodes.  This constrains bin transfers to a
316	<	* particular order, and so can block indefinitely waiting for the
317	<	* next lock, and other threads cannot help with the transfer.
318	<	* However, expected stalls are infrequent enough to not warrant
319	<	* the additional overhead of access and iteration schemes that
320	<	* could admit out-of-order or concurrent bin transfers.
297	>	* elements is roughly 1 / (8 * #elements) under random hashes.
298	>	*
299	>	* Actual hash code distributions encountered in practice
300	>	* sometimes deviate significantly from uniform randomness.  This
301	>	* includes the case when N > (1<<30), so some keys MUST collide.
302	>	* Similarly for dumb or hostile usages in which multiple keys are
303	>	* designed to have identical hash codes. Also, although we guard
304	>	* against the worst effects of this (see method spread), sets of
305	>	* hashes may differ only in bits that do not impact their bin
306	>	* index for a given power-of-two mask.  So we use a secondary
307	>	* strategy that applies when the number of nodes in a bin exceeds
308	>	* a threshold, and at least one of the keys implements
309	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
310	>	* (a specialized form of red-black trees), bounding search time
311	>	* to O(log N).  Each search step in a TreeBin is around twice as
312	>	* slow as in a regular list, but given that N cannot exceed
313	>	* (1<<64) (before running out of addresses) this bounds search
314	>	* steps, lock hold times, etc, to reasonable constants (roughly
315	>	* 100 nodes inspected per operation worst case) so long as keys
316	>	* are Comparable (which is very common -- String, Long, etc).
317	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
318	>	* traversal pointers as regular nodes, so can be traversed in
319	>	* iterators in the same way.
320	>	*
321	>	* The table is resized when occupancy exceeds a percentage
322	>	* threshold (nominally, 0.75, but see below).  Only a single
323	>	* thread performs the resize (using field "sizeCtl", to arrange
324	>	* exclusion), but the table otherwise remains usable for reads
325	>	* and updates. Resizing proceeds by transferring bins, one by
326	>	* one, from the table to the next table.  Because we are using
327	>	* power-of-two expansion, the elements from each bin must either
328	>	* stay at same index, or move with a power of two offset. We
329	>	* eliminate unnecessary node creation by catching cases where old
330	>	* nodes can be reused because their next fields won't change.  On
331	>	* average, only about one-sixth of them need cloning when a table
332	>	* doubles. The nodes they replace will be garbage collectable as
333	>	* soon as they are no longer referenced by any reader thread that
334	>	* may be in the midst of concurrently traversing table.  Upon
335	>	* transfer, the old table bin contains only a special forwarding
336	>	* node (with hash field "MOVED") that contains the next table as
337	>	* its key. On encountering a forwarding node, access and update
338	>	* operations restart, using the new table.
339	>	*
340	>	* Each bin transfer requires its bin lock. However, unlike other
341	>	* cases, a transfer can skip a bin if it fails to acquire its
342	>	* lock, and revisit it later (unless it is a TreeBin). Method
343	>	* rebuild maintains a buffer of TRANSFER_BUFFER_SIZE bins that
344	>	* have been skipped because of failure to acquire a lock, and
345	>	* blocks only if none are available (i.e., only very rarely).
346	>	* The transfer operation must also ensure that all accessible
347	>	* bins in both the old and new table are usable by any traversal.
348	>	* When there are no lock acquisition failures, this is arranged
349	>	* simply by proceeding from the last bin (table.length - 1) up
350	>	* towards the first.  Upon seeing a forwarding node, traversals
351	>	* (see class InternalIterator) arrange to move to the new table
352	>	* without revisiting nodes.  However, when any node is skipped
353	>	* during a transfer, all earlier table bins may have become
354	>	* visible, so are initialized with a reverse-forwarding node back
355	>	* to the old table until the new ones are established. (This
356	>	* sometimes requires transiently locking a forwarding node, which
357	>	* is possible under the above encoding.) These more expensive
358	>	* mechanics trigger only when necessary.
359		*
360	<	* This traversal scheme also applies to partial traversals of
360	>	* The traversal scheme also applies to partial traversals of
361		* ranges of bins (via an alternate InternalIterator constructor)
362	<	* to support partitioned aggregate operations (that are not
363	<	* otherwise implemented yet).  Also, read-only operations give up
364	<	* if ever forwarded to a null table, which provides support for
365	<	* shutdown-style clearing, which is also not currently
216	<	* implemented.
362	>	* to support partitioned aggregate operations.  Also, read-only
363	>	* operations give up if ever forwarded to a null table, which
364	>	* provides support for shutdown-style clearing, which is also not
365	>	* currently implemented.
366		*
367		* Lazy table initialization minimizes footprint until first use,
368		* and also avoids resizings when the first operation is from a
369		* putAll, constructor with map argument, or deserialization.
370	<	* These cases attempt to override the targetCapacity used in
371	<	* growTable. These harmlessly fail to take effect in cases of
223	<	* races with other ongoing resizings. Uses of the threshold and
224	<	* targetCapacity during attempted initializations or resizings
225	<	* are racy but fall back on checks to preserve correctness.
370	>	* These cases attempt to override the initial capacity settings,
371	>	* but harmlessly fail to take effect in cases of races.
372		*
373		* The element count is maintained using a LongAdder, which avoids
374		* contention on updates but can encounter cache thrashing if read
375		* too frequently during concurrent access. To avoid reading so
376	<	* often, resizing is normally attempted only upon adding to a bin
377	<	* already holding two or more nodes. Under uniform hash
378	<	* distributions, the probability of this occurring at threshold
379	<	* is around 13%, meaning that only about 1 in 8 puts check
380	<	* threshold (and after resizing, many fewer do so). But this
381	<	* approximation has high variance for small table sizes, so we
382	<	* check on any collision for sizes <= 64.  Further, to increase
383	<	* the probability that a resize occurs soon enough, we offset the
384	<	* threshold (see THRESHOLD_OFFSET) by the expected number of puts
385	<	* between checks.
376	>	* often, resizing is attempted either when a bin lock is
377	>	* contended, or upon adding to a bin already holding two or more
378	>	* nodes (checked before adding in the xIfAbsent methods, after
379	>	* adding in others). Under uniform hash distributions, the
380	>	* probability of this occurring at threshold is around 13%,
381	>	* meaning that only about 1 in 8 puts check threshold (and after
382	>	* resizing, many fewer do so). But this approximation has high
383	>	* variance for small table sizes, so we check on any collision
384	>	* for sizes <= 64. The bulk putAll operation further reduces
385	>	* contention by only committing count updates upon these size
386	>	* checks.
387		*
388		* Maintaining API and serialization compatibility with previous
389		* versions of this class introduces several oddities. Mainly: We
390		* leave untouched but unused constructor arguments refering to
391	<	* concurrencyLevel. We also declare an unused "Segment" class
392	<	* that is instantiated in minimal form only when serializing.
391	>	* concurrencyLevel. We accept a loadFactor constructor argument,
392	>	* but apply it only to initial table capacity (which is the only
393	>	* time that we can guarantee to honor it.) We also declare an
394	>	* unused "Segment" class that is instantiated in minimal form
395	>	* only when serializing.
396		*/
397
398		/* ---------------- Constants -------------- */
#	Line 250 | Line 400 | public class ConcurrentHashMapV8<K, V>
400		/**
401		* The largest possible table capacity.  This value must be
402		* exactly 1<<30 to stay within Java array allocation and indexing
403	<	* bounds for power of two table sizes.
403	>	* bounds for power of two table sizes, and is further required
404	>	* because the top two bits of 32bit hash fields are used for
405	>	* control purposes.
406		*/
407		private static final int MAXIMUM_CAPACITY = 1 << 30;
408
#	Line 261 | Line 413 | public class ConcurrentHashMapV8<K, V>
413		private static final int DEFAULT_CAPACITY = 16;
414
415		/**
416	<	* The load factor for this table. Overrides of this value in
417	<	* constructors affect only the initial table capacity.  The
266	<	* actual floating point value isn't normally used, because it is
267	<	* simpler to rely on the expression {@code n - (n >>> 2)} for the
268	<	* associated resizing threshold.
416	>	* The largest possible (non-power of two) array size.
417	>	* Needed by toArray and related methods.
418		*/
419	<	private static final float LOAD_FACTOR = 0.75f;
419	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
420
421		/**
422	<	* The count value to offset thresholds to compensate for checking
423	<	* for the need to resize only when inserting into bins with two
275	<	* or more elements. See above for explanation.
422	>	* The default concurrency level for this table. Unused but
423	>	* defined for compatibility with previous versions of this class.
424		*/
425	<	private static final int THRESHOLD_OFFSET = 8;
425	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
426
427		/**
428	<	* The default concurrency level for this table. Unused except as
429	<	* a sizing hint, but defined for compatibility with previous
430	<	* versions of this class.
428	>	* The load factor for this table. Overrides of this value in
429	>	* constructors affect only the initial table capacity.  The
430	>	* actual floating point value isn't normally used -- it is
431	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
432	>	* the associated resizing threshold.
433		*/
434	<	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
285	<
286	<	/* ---------------- Nodes -------------- */
434	>	private static final float LOAD_FACTOR = 0.75f;
435
436		/**
437	<	* Key-value entry. Note that this is never exported out as a
438	<	* user-visible Map.Entry. Nodes with a negative hash field are
439	<	* special, and do not contain user keys or values.  Otherwise,
292	<	* keys are never null, and null val fields indicate that a node
293	<	* is in the process of being deleted or created. For purposes of
294	<	* read-only, access, a key may be read before a val, but can only
295	<	* be used after checking val.  (For an update operation, when a
296	<	* lock is held on a node, order doesn't matter.)
437	>	* The buffer size for skipped bins during transfers. The
438	>	* value is arbitrary but should be large enough to avoid
439	>	* most locking stalls during resizes.
440		*/
441	<	static final class Node {
299	<	final int hash;
300	<	final Object key;
301	<	volatile Object val;
302	<	volatile Node next;
303	<
304	<	Node(int hash, Object key, Object val, Node next) {
305	<	this.hash = hash;
306	<	this.key = key;
307	<	this.val = val;
308	<	this.next = next;
309	<	}
310	<	}
441	>	private static final int TRANSFER_BUFFER_SIZE = 32;
442
443		/**
444	<	* Sign bit of node hash value indicating to use table in node.key.
444	>	* The bin count threshold for using a tree rather than list for a
445	>	* bin.  The value reflects the approximate break-even point for
446	>	* using tree-based operations.
447		*/
448	<	private static final int SIGN_BIT = 0x80000000;
448	>	private static final int TREE_THRESHOLD = 8;
449	>
450	>	/*
451	>	* Encodings for special uses of Node hash fields. See above for
452	>	* explanation.
453	>	*/
454	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
455	>	static final int LOCKED    = 0x40000000; // set/tested only as a bit
456	>	static final int WAITING   = 0xc0000000; // both bits set/tested together
457	>	static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
458
459		/* ---------------- Fields -------------- */
460
#	Line 322 | Line 464 | public class ConcurrentHashMapV8<K, V>
464		*/
465		transient volatile Node[] table;
466
467	<	/** The counter maintaining number of elements. */
467	>	/**
468	>	* The counter maintaining number of elements.
469	>	*/
470		private transient final LongAdder counter;
471	<	/** Nonzero when table is being initialized or resized. Updated via CAS. */
472	<	private transient volatile int resizing;
473	<	/** The next element count value upon which to resize the table. */
474	<	private transient int threshold;
475	<	/** The target capacity; volatile to cover initialization races. */
476	<	private transient volatile int targetCapacity;
471	>
472	>	/**
473	>	* Table initialization and resizing control.  When negative, the
474	>	* table is being initialized or resized. Otherwise, when table is
475	>	* null, holds the initial table size to use upon creation, or 0
476	>	* for default. After initialization, holds the next element count
477	>	* value upon which to resize the table.
478	>	*/
479	>	private transient volatile int sizeCtl;
480
481		// views
482		private transient KeySet<K,V> keySet;
#	Line 365 | Line 512 | public class ConcurrentHashMapV8<K, V>
512		UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
513		}
514
515	<	/* ----------------Table Initialization and Resizing -------------- */
515	>	/* ---------------- Nodes -------------- */
516
517		/**
518	<	* Returns a power of two table size for the given desired capacity.
519	<	* See Hackers Delight, sec 3.2
518	>	* Key-value entry. Note that this is never exported out as a
519	>	* user-visible Map.Entry (see MapEntry below). Nodes with a hash
520	>	* field of MOVED are special, and do not contain user keys or
521	>	* values.  Otherwise, keys are never null, and null val fields
522	>	* indicate that a node is in the process of being deleted or
523	>	* created. For purposes of read-only access, a key may be read
524	>	* before a val, but can only be used after checking val to be
525	>	* non-null.
526		*/
527	<	private static final int tableSizeFor(int c) {
528	<	int n = c - 1;
529	<	n |= n >>> 1;
530	<	n |= n >>> 2;
531	<	n |= n >>> 4;
379	<	n |= n >>> 8;
380	<	n |= n >>> 16;
381	<	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
382	<	}
527	>	static class Node {
528	>	volatile int hash;
529	>	final Object key;
530	>	volatile Object val;
531	>	volatile Node next;
532
533	<	/**
534	<	* If not already resizing, initializes or creates next table and
535	<	* transfers bins. Initial table size uses the capacity recorded
536	<	* in targetCapacity.  Rechecks occupancy after a transfer to see
537	<	* if another resize is already needed because resizings are
538	<	* lagging additions.
539	<	*
540	<	* @return current table
541	<	*/
542	<	private final Node[] growTable() {
543	<	if (resizing == 0 &&
544	<	UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
545	<	try {
546	<	for (;;) {
547	<	Node[] tab = table;
548	<	int n, c, m;
549	<	if (tab == null)
550	<	n = (c = targetCapacity) > 0 ? c : DEFAULT_CAPACITY;
551	<	else if ((m = tab.length) < MAXIMUM_CAPACITY &&
552	<	counter.sum() >= (long)threshold)
553	<	n = m << 1;
554	<	else
555	<	break;
556	<	threshold = n - (n >>> 2) - THRESHOLD_OFFSET;
557	<	Node[] nextTab = new Node[n];
558	<	if (tab != null)
559	<	transfer(tab, nextTab,
560	<	new Node(SIGN_BIT, nextTab, null, null));
561	<	table = nextTab;
562	<	if (tab == null)
533	>	Node(int hash, Object key, Object val, Node next) {
534	>	this.hash = hash;
535	>	this.key = key;
536	>	this.val = val;
537	>	this.next = next;
538	>	}
539	>
540	>	/** CompareAndSet the hash field */
541	>	final boolean casHash(int cmp, int val) {
542	>	return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
543	>	}
544	>
545	>	/** The number of spins before blocking for a lock */
546	>	static final int MAX_SPINS =
547	>	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
548	>
549	>	/**
550	>	* Spins a while if LOCKED bit set and this node is the first
551	>	* of its bin, and then sets WAITING bits on hash field and
552	>	* blocks (once) if they are still set.  It is OK for this
553	>	* method to return even if lock is not available upon exit,
554	>	* which enables these simple single-wait mechanics.
555	>	*
556	>	* The corresponding signalling operation is performed within
557	>	* callers: Upon detecting that WAITING has been set when
558	>	* unlocking lock (via a failed CAS from non-waiting LOCKED
559	>	* state), unlockers acquire the sync lock and perform a
560	>	* notifyAll.
561	>	*/
562	>	final void tryAwaitLock(Node[] tab, int i) {
563	>	if (tab != null && i >= 0 && i < tab.length) { // bounds check
564	>	int r = ThreadLocalRandom.current().nextInt(); // randomize spins
565	>	int spins = MAX_SPINS, h;
566	>	while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
567	>	if (spins >= 0) {
568	>	r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
569	>	if (r >= 0 && --spins == 0)
570	>	Thread.yield();  // yield before block
571	>	}
572	>	else if (casHash(h, h | WAITING)) {
573	>	synchronized (this) {
574	>	if (tabAt(tab, i) == this &&
575	>	(hash & WAITING) == WAITING) {
576	>	try {
577	>	wait();
578	>	} catch (InterruptedException ie) {
579	>	Thread.currentThread().interrupt();
580	>	}
581	>	}
582	>	else
583	>	notifyAll(); // possibly won race vs signaller
584	>	}
585		break;
586	+	}
587		}
416	–	} finally {
417	–	resizing = 0;
588		}
589		}
590	<	else if (table == null)
591	<	Thread.yield(); // lost initialization race; just spin
592	<	return table;
590	>
591	>	// Unsafe mechanics for casHash
592	>	private static final sun.misc.Unsafe UNSAFE;
593	>	private static final long hashOffset;
594	>
595	>	static {
596	>	try {
597	>	UNSAFE = getUnsafe();
598	>	Class<?> k = Node.class;
599	>	hashOffset = UNSAFE.objectFieldOffset
600	>	(k.getDeclaredField("hash"));
601	>	} catch (Exception e) {
602	>	throw new Error(e);
603	>	}
604	>	}
605		}
606
607	<	/*
608	<	* Reclassifies nodes in each bin to new table.  Because we are
609	<	* using power-of-two expansion, the elements from each bin must
610	<	* either stay at same index, or move with a power of two
429	<	* offset. We eliminate unnecessary node creation by catching
430	<	* cases where old nodes can be reused because their next fields
431	<	* won't change.  Statistically, only about one-sixth of them need
432	<	* cloning when a table doubles. The nodes they replace will be
433	<	* garbage collectable as soon as they are no longer referenced by
434	<	* any reader thread that may be in the midst of concurrently
435	<	* traversing table.
436	<	*
437	<	* Transfers are done from the bottom up to preserve iterator
438	<	* traversability. On each step, the old bin is locked,
439	<	* moved/copied, and then replaced with a forwarding node.
607	>	/* ---------------- TreeBins -------------- */
608	>
609	>	/**
610	>	* Nodes for use in TreeBins
611		*/
612	<	private static final void transfer(Node[] tab, Node[] nextTab, Node fwd) {
613	<	int n = tab.length;
614	<	Node ignore = nextTab[n + n - 1]; // force bounds check
615	<	for (int i = n - 1; i >= 0; --i) {
616	<	for (Node e;;) {
617	<	if ((e = tabAt(tab, i)) != null) {
618	<	boolean validated = false;
619	<	synchronized (e) {
620	<	if (tabAt(tab, i) == e) {
621	<	validated = true;
622	<	Node lo = null, hi = null, lastRun = e;
623	<	int runBit = e.hash & n;
624	<	for (Node p = e.next; p != null; p = p.next) {
625	<	int b = p.hash & n;
626	<	if (b != runBit) {
627	<	runBit = b;
628	<	lastRun = p;
612	>	static final class TreeNode extends Node {
613	>	TreeNode parent;  // red-black tree links
614	>	TreeNode left;
615	>	TreeNode right;
616	>	TreeNode prev;    // needed to unlink next upon deletion
617	>	boolean red;
618	>
619	>	TreeNode(int hash, Object key, Object val, Node next, TreeNode parent) {
620	>	super(hash, key, val, next);
621	>	this.parent = parent;
622	>	}
623	>	}
624	>
625	>	/**
626	>	* A specialized form of red-black tree for use in bins
627	>	* whose size exceeds a threshold.
628	>	*
629	>	* TreeBins use a special form of comparison for search and
630	>	* related operations (which is the main reason we cannot use
631	>	* existing collections such as TreeMaps). TreeBins contain
632	>	* Comparable elements, but may contain others, as well as
633	>	* elements that are Comparable but not necessarily Comparable<T>
634	>	* for the same T, so we cannot invoke compareTo among them. To
635	>	* handle this, the tree is ordered primarily by hash value, then
636	>	* by getClass().getName() order, and then by Comparator order
637	>	* among elements of the same class.  On lookup at a node, if
638	>	* elements are not comparable or compare as 0, both left and
639	>	* right children may need to be searched in the case of tied hash
640	>	* values. (This corresponds to the full list search that would be
641	>	* necessary if all elements were non-Comparable and had tied
642	>	* hashes.)  The red-black balancing code is updated from
643	>	* pre-jdk-collections
644	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
645	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
646	>	* Algorithms" (CLR).
647	>	*
648	>	* TreeBins also maintain a separate locking discipline than
649	>	* regular bins. Because they are forwarded via special MOVED
650	>	* nodes at bin heads (which can never change once established),
651	>	* we cannot use use those nodes as locks. Instead, TreeBin
652	>	* extends AbstractQueuedSynchronizer to support a simple form of
653	>	* read-write lock. For update operations and table validation,
654	>	* the exclusive form of lock behaves in the same way as bin-head
655	>	* locks. However, lookups use shared read-lock mechanics to allow
656	>	* multiple readers in the absence of writers.  Additionally,
657	>	* these lookups do not ever block: While the lock is not
658	>	* available, they proceed along the slow traversal path (via
659	>	* next-pointers) until the lock becomes available or the list is
660	>	* exhausted, whichever comes first. (These cases are not fast,
661	>	* but maximize aggregate expected throughput.)  The AQS mechanics
662	>	* for doing this are straightforward.  The lock state is held as
663	>	* AQS getState().  Read counts are negative; the write count (1)
664	>	* is positive.  There are no signalling preferences among readers
665	>	* and writers. Since we don't need to export full Lock API, we
666	>	* just override the minimal AQS methods and use them directly.
667	>	*/
668	>	static final class TreeBin extends AbstractQueuedSynchronizer {
669	>	private static final long serialVersionUID = 2249069246763182397L;
670	>	transient TreeNode root;  // root of tree
671	>	transient TreeNode first; // head of next-pointer list
672	>
673	>	/* AQS overrides */
674	>	public final boolean isHeldExclusively() { return getState() > 0; }
675	>	public final boolean tryAcquire(int ignore) {
676	>	if (compareAndSetState(0, 1)) {
677	>	setExclusiveOwnerThread(Thread.currentThread());
678	>	return true;
679	>	}
680	>	return false;
681	>	}
682	>	public final boolean tryRelease(int ignore) {
683	>	setExclusiveOwnerThread(null);
684	>	setState(0);
685	>	return true;
686	>	}
687	>	public final int tryAcquireShared(int ignore) {
688	>	for (int c;;) {
689	>	if ((c = getState()) > 0)
690	>	return -1;
691	>	if (compareAndSetState(c, c -1))
692	>	return 1;
693	>	}
694	>	}
695	>	public final boolean tryReleaseShared(int ignore) {
696	>	int c;
697	>	do {} while (!compareAndSetState(c = getState(), c + 1));
698	>	return c == -1;
699	>	}
700	>
701	>	/** From CLR */
702	>	private void rotateLeft(TreeNode p) {
703	>	if (p != null) {
704	>	TreeNode r = p.right, pp, rl;
705	>	if ((rl = p.right = r.left) != null)
706	>	rl.parent = p;
707	>	if ((pp = r.parent = p.parent) == null)
708	>	root = r;
709	>	else if (pp.left == p)
710	>	pp.left = r;
711	>	else
712	>	pp.right = r;
713	>	r.left = p;
714	>	p.parent = r;
715	>	}
716	>	}
717	>
718	>	/** From CLR */
719	>	private void rotateRight(TreeNode p) {
720	>	if (p != null) {
721	>	TreeNode l = p.left, pp, lr;
722	>	if ((lr = p.left = l.right) != null)
723	>	lr.parent = p;
724	>	if ((pp = l.parent = p.parent) == null)
725	>	root = l;
726	>	else if (pp.right == p)
727	>	pp.right = l;
728	>	else
729	>	pp.left = l;
730	>	l.right = p;
731	>	p.parent = l;
732	>	}
733	>	}
734	>
735	>	/**
736	>	* Return the TreeNode (or null if not found) for the given key
737	>	* starting at given root.
738	>	*/
739	>	@SuppressWarnings("unchecked") // suppress Comparable cast warning
740	>	final TreeNode getTreeNode(int h, Object k, TreeNode p) {
741	>	Class<?> c = k.getClass();
742	>	while (p != null) {
743	>	int dir, ph;  Object pk; Class<?> pc;
744	>	if ((ph = p.hash) == h) {
745	>	if ((pk = p.key) == k || k.equals(pk))
746	>	return p;
747	>	if (c != (pc = pk.getClass()) ||
748	>	!(k instanceof Comparable) ||
749	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
750	>	dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
751	>	TreeNode r = null, s = null, pl, pr;
752	>	if (dir >= 0) {
753	>	if ((pl = p.left) != null && h <= pl.hash)
754	>	s = pl;
755	>	}
756	>	else if ((pr = p.right) != null && h >= pr.hash)
757	>	s = pr;
758	>	if (s != null && (r = getTreeNode(h, k, s)) != null)
759	>	return r;
760	>	}
761	>	}
762	>	else
763	>	dir = (h < ph) ? -1 : 1;
764	>	p = (dir > 0) ? p.right : p.left;
765	>	}
766	>	return null;
767	>	}
768	>
769	>	/**
770	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
771	>	* read-lock to call getTreeNode, but during failure to get
772	>	* lock, searches along next links.
773	>	*/
774	>	final Object getValue(int h, Object k) {
775	>	Node r = null;
776	>	int c = getState(); // Must read lock state first
777	>	for (Node e = first; e != null; e = e.next) {
778	>	if (c <= 0 && compareAndSetState(c, c - 1)) {
779	>	try {
780	>	r = getTreeNode(h, k, root);
781	>	} finally {
782	>	releaseShared(0);
783	>	}
784	>	break;
785	>	}
786	>	else if ((e.hash & HASH_BITS) == h && k.equals(e.key)) {
787	>	r = e;
788	>	break;
789	>	}
790	>	else
791	>	c = getState();
792	>	}
793	>	return r == null ? null : r.val;
794	>	}
795	>
796	>	/**
797	>	* Finds or adds a node.
798	>	* @return null if added
799	>	*/
800	>	@SuppressWarnings("unchecked") // suppress Comparable cast warning
801	>	final TreeNode putTreeNode(int h, Object k, Object v) {
802	>	Class<?> c = k.getClass();
803	>	TreeNode pp = root, p = null;
804	>	int dir = 0;
805	>	while (pp != null) { // find existing node or leaf to insert at
806	>	int ph;  Object pk; Class<?> pc;
807	>	p = pp;
808	>	if ((ph = p.hash) == h) {
809	>	if ((pk = p.key) == k || k.equals(pk))
810	>	return p;
811	>	if (c != (pc = pk.getClass()) ||
812	>	!(k instanceof Comparable) ||
813	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
814	>	dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
815	>	TreeNode r = null, s = null, pl, pr;
816	>	if (dir >= 0) {
817	>	if ((pl = p.left) != null && h <= pl.hash)
818	>	s = pl;
819	>	}
820	>	else if ((pr = p.right) != null && h >= pr.hash)
821	>	s = pr;
822	>	if (s != null && (r = getTreeNode(h, k, s)) != null)
823	>	return r;
824	>	}
825	>	}
826	>	else
827	>	dir = (h < ph) ? -1 : 1;
828	>	pp = (dir > 0) ? p.right : p.left;
829	>	}
830	>
831	>	TreeNode f = first;
832	>	TreeNode x = first = new TreeNode(h, k, v, f, p);
833	>	if (p == null)
834	>	root = x;
835	>	else { // attach and rebalance; adapted from CLR
836	>	TreeNode xp, xpp;
837	>	if (f != null)
838	>	f.prev = x;
839	>	if (dir <= 0)
840	>	p.left = x;
841	>	else
842	>	p.right = x;
843	>	x.red = true;
844	>	while (x != null && (xp = x.parent) != null && xp.red &&
845	>	(xpp = xp.parent) != null) {
846	>	TreeNode xppl = xpp.left;
847	>	if (xp == xppl) {
848	>	TreeNode y = xpp.right;
849	>	if (y != null && y.red) {
850	>	y.red = false;
851	>	xp.red = false;
852	>	xpp.red = true;
853	>	x = xpp;
854	>	}
855	>	else {
856	>	if (x == xp.right) {
857	>	rotateLeft(x = xp);
858	>	xpp = (xp = x.parent) == null ? null : xp.parent;
859	>	}
860	>	if (xp != null) {
861	>	xp.red = false;
862	>	if (xpp != null) {
863	>	xpp.red = true;
864	>	rotateRight(xpp);
865		}
866		}
867	<	if (runBit == 0)
868	<	lo = lastRun;
869	<	else
870	<	hi = lastRun;
871	<	for (Node p = e; p != lastRun; p = p.next) {
872	<	int ph = p.hash;
873	<	Object pk = p.key, pv = p.val;
874	<	if ((ph & n) == 0)
875	<	lo = new Node(ph, pk, pv, lo);
876	<	else
877	<	hi = new Node(ph, pk, pv, hi);
867	>	}
868	>	}
869	>	else {
870	>	TreeNode y = xppl;
871	>	if (y != null && y.red) {
872	>	y.red = false;
873	>	xp.red = false;
874	>	xpp.red = true;
875	>	x = xpp;
876	>	}
877	>	else {
878	>	if (x == xp.left) {
879	>	rotateRight(x = xp);
880	>	xpp = (xp = x.parent) == null ? null : xp.parent;
881	>	}
882	>	if (xp != null) {
883	>	xp.red = false;
884	>	if (xpp != null) {
885	>	xpp.red = true;
886	>	rotateLeft(xpp);
887	>	}
888		}
472	–	setTabAt(nextTab, i, lo);
473	–	setTabAt(nextTab, i + n, hi);
474	–	setTabAt(tab, i, fwd);
889		}
890		}
891	<	if (validated)
891	>	}
892	>	TreeNode r = root;
893	>	if (r != null && r.red)
894	>	r.red = false;
895	>	}
896	>	return null;
897	>	}
898	>
899	>	/**
900	>	* Removes the given node, that must be present before this
901	>	* call.  This is messier than typical red-black deletion code
902	>	* because we cannot swap the contents of an interior node
903	>	* with a leaf successor that is pinned by "next" pointers
904	>	* that are accessible independently of lock. So instead we
905	>	* swap the tree linkages.
906	>	*/
907	>	final void deleteTreeNode(TreeNode p) {
908	>	TreeNode next = (TreeNode)p.next; // unlink traversal pointers
909	>	TreeNode pred = p.prev;
910	>	if (pred == null)
911	>	first = next;
912	>	else
913	>	pred.next = next;
914	>	if (next != null)
915	>	next.prev = pred;
916	>	TreeNode replacement;
917	>	TreeNode pl = p.left;
918	>	TreeNode pr = p.right;
919	>	if (pl != null && pr != null) {
920	>	TreeNode s = pr, sl;
921	>	while ((sl = s.left) != null) // find successor
922	>	s = sl;
923	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
924	>	TreeNode sr = s.right;
925	>	TreeNode pp = p.parent;
926	>	if (s == pr) { // p was s's direct parent
927	>	p.parent = s;
928	>	s.right = p;
929	>	}
930	>	else {
931	>	TreeNode sp = s.parent;
932	>	if ((p.parent = sp) != null) {
933	>	if (s == sp.left)
934	>	sp.left = p;
935	>	else
936	>	sp.right = p;
937	>	}
938	>	if ((s.right = pr) != null)
939	>	pr.parent = s;
940	>	}
941	>	p.left = null;
942	>	if ((p.right = sr) != null)
943	>	sr.parent = p;
944	>	if ((s.left = pl) != null)
945	>	pl.parent = s;
946	>	if ((s.parent = pp) == null)
947	>	root = s;
948	>	else if (p == pp.left)
949	>	pp.left = s;
950	>	else
951	>	pp.right = s;
952	>	replacement = sr;
953	>	}
954	>	else
955	>	replacement = (pl != null) ? pl : pr;
956	>	TreeNode pp = p.parent;
957	>	if (replacement == null) {
958	>	if (pp == null) {
959	>	root = null;
960	>	return;
961	>	}
962	>	replacement = p;
963	>	}
964	>	else {
965	>	replacement.parent = pp;
966	>	if (pp == null)
967	>	root = replacement;
968	>	else if (p == pp.left)
969	>	pp.left = replacement;
970	>	else
971	>	pp.right = replacement;
972	>	p.left = p.right = p.parent = null;
973	>	}
974	>	if (!p.red) { // rebalance, from CLR
975	>	TreeNode x = replacement;
976	>	while (x != null) {
977	>	TreeNode xp, xpl;
978	>	if (x.red || (xp = x.parent) == null) {
979	>	x.red = false;
980		break;
981	+	}
982	+	if (x == (xpl = xp.left)) {
983	+	TreeNode sib = xp.right;
984	+	if (sib != null && sib.red) {
985	+	sib.red = false;
986	+	xp.red = true;
987	+	rotateLeft(xp);
988	+	sib = (xp = x.parent) == null ? null : xp.right;
989	+	}
990	+	if (sib == null)
991	+	x = xp;
992	+	else {
993	+	TreeNode sl = sib.left, sr = sib.right;
994	+	if ((sr == null || !sr.red) &&
995	+	(sl == null || !sl.red)) {
996	+	sib.red = true;
997	+	x = xp;
998	+	}
999	+	else {
1000	+	if (sr == null || !sr.red) {
1001	+	if (sl != null)
1002	+	sl.red = false;
1003	+	sib.red = true;
1004	+	rotateRight(sib);
1005	+	sib = (xp = x.parent) == null ? null : xp.right;
1006	+	}
1007	+	if (sib != null) {
1008	+	sib.red = (xp == null) ? false : xp.red;
1009	+	if ((sr = sib.right) != null)
1010	+	sr.red = false;
1011	+	}
1012	+	if (xp != null) {
1013	+	xp.red = false;
1014	+	rotateLeft(xp);
1015	+	}
1016	+	x = root;
1017	+	}
1018	+	}
1019	+	}
1020	+	else { // symmetric
1021	+	TreeNode sib = xpl;
1022	+	if (sib != null && sib.red) {
1023	+	sib.red = false;
1024	+	xp.red = true;
1025	+	rotateRight(xp);
1026	+	sib = (xp = x.parent) == null ? null : xp.left;
1027	+	}
1028	+	if (sib == null)
1029	+	x = xp;
1030	+	else {
1031	+	TreeNode sl = sib.left, sr = sib.right;
1032	+	if ((sl == null || !sl.red) &&
1033	+	(sr == null || !sr.red)) {
1034	+	sib.red = true;
1035	+	x = xp;
1036	+	}
1037	+	else {
1038	+	if (sl == null || !sl.red) {
1039	+	if (sr != null)
1040	+	sr.red = false;
1041	+	sib.red = true;
1042	+	rotateLeft(sib);
1043	+	sib = (xp = x.parent) == null ? null : xp.left;
1044	+	}
1045	+	if (sib != null) {
1046	+	sib.red = (xp == null) ? false : xp.red;
1047	+	if ((sl = sib.left) != null)
1048	+	sl.red = false;
1049	+	}
1050	+	if (xp != null) {
1051	+	xp.red = false;
1052	+	rotateRight(xp);
1053	+	}
1054	+	x = root;
1055	+	}
1056	+	}
1057	+	}
1058		}
1059	<	else if (casTabAt(tab, i, e, fwd))
1060	<	break;
1059	>	}
1060	>	if (p == replacement && (pp = p.parent) != null) {
1061	>	if (p == pp.left) // detach pointers
1062	>	pp.left = null;
1063	>	else if (p == pp.right)
1064	>	pp.right = null;
1065	>	p.parent = null;
1066		}
1067		}
1068		}
1069
1070	<	/* ---------------- Internal access and update methods -------------- */
1070	>	/* ---------------- Collision reduction methods -------------- */
1071
1072		/**
1073	<	* Applies a supplemental hash function to a given hashCode, which
1074	<	* defends against poor quality hash functions.  The result must
1075	<	* be non-negative, and for reasonable performance must have good
1076	<	* avalanche properties; i.e., that each bit of the argument
1077	<	* affects each bit (except sign bit) of the result.
1073	>	* Spreads higher bits to lower, and also forces top 2 bits to 0.
1074	>	* Because the table uses power-of-two masking, sets of hashes
1075	>	* that vary only in bits above the current mask will always
1076	>	* collide. (Among known examples are sets of Float keys holding
1077	>	* consecutive whole numbers in small tables.)  To counter this,
1078	>	* we apply a transform that spreads the impact of higher bits
1079	>	* downward. There is a tradeoff between speed, utility, and
1080	>	* quality of bit-spreading. Because many common sets of hashes
1081	>	* are already reasonably distributed across bits (so don't benefit
1082	>	* from spreading), and because we use trees to handle large sets
1083	>	* of collisions in bins, we don't need excessively high quality.
1084		*/
1085		private static final int spread(int h) {
1086	<	// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
1087	<	h ^= h >>> 16;
1088	<	h *= 0x85ebca6b;
1089	<	h ^= h >>> 13;
1090	<	h *= 0xc2b2ae35;
1091	<	return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit
1086	>	h ^= (h >>> 18) ^ (h >>> 12);
1087	>	return (h ^ (h >>> 10)) & HASH_BITS;
1088	>	}
1089	>
1090	>	/**
1091	>	* Replaces a list bin with a tree bin. Call only when locked.
1092	>	* Fails to replace if the given key is non-comparable or table
1093	>	* is, or needs, resizing.
1094	>	*/
1095	>	private final void replaceWithTreeBin(Node[] tab, int index, Object key) {
1096	>	if ((key instanceof Comparable) &&
1097	>	(tab.length >= MAXIMUM_CAPACITY || counter.sum() < (long)sizeCtl)) {
1098	>	TreeBin t = new TreeBin();
1099	>	for (Node e = tabAt(tab, index); e != null; e = e.next)
1100	>	t.putTreeNode(e.hash & HASH_BITS, e.key, e.val);
1101	>	setTabAt(tab, index, new Node(MOVED, t, null, null));
1102	>	}
1103		}
1104
1105	+	/* ---------------- Internal access and update methods -------------- */
1106	+
1107		/** Implementation for get and containsKey */
1108		private final Object internalGet(Object k) {
1109		int h = spread(k.hashCode());
1110		retry: for (Node[] tab = table; tab != null;) {
1111	<	Node e; Object ek, ev; int eh;  // locals to read fields once
1111	>	Node e, p; Object ek, ev; int eh;      // locals to read fields once
1112		for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1113	<	if ((eh = e.hash) == h) {
1114	<	if ((ev = e.val) != null &&
1115	<	((ek = e.key) == k || k.equals(ek)))
1116	<	return ev;
1117	<	}
1118	<	else if (eh < 0) {          // sign bit set
1119	<	tab = (Node[])e.key;    // bin was moved during resize
517	<	continue retry;
1113	>	if ((eh = e.hash) == MOVED) {
1114	>	if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1115	>	return ((TreeBin)ek).getValue(h, k);
1116	>	else {                        // restart with new table
1117	>	tab = (Node[])ek;
1118	>	continue retry;
1119	>	}
1120		}
1121	+	else if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
1122	+	((ek = e.key) == k || k.equals(ek)))
1123	+	return ev;
1124		}
1125		break;
1126		}
1127		return null;
1128		}
1129
1130	<	/** Implementation for put and putIfAbsent */
1131	<	private final Object internalPut(Object k, Object v, boolean replace) {
1130	>	/**
1131	>	* Implementation for the four public remove/replace methods:
1132	>	* Replaces node value with v, conditional upon match of cv if
1133	>	* non-null.  If resulting value is null, delete.
1134	>	*/
1135	>	private final Object internalReplace(Object k, Object v, Object cv) {
1136	>	int h = spread(k.hashCode());
1137	>	Object oldVal = null;
1138	>	for (Node[] tab = table;;) {
1139	>	Node f; int i, fh; Object fk;
1140	>	if (tab == null ||
1141	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1142	>	break;
1143	>	else if ((fh = f.hash) == MOVED) {
1144	>	if ((fk = f.key) instanceof TreeBin) {
1145	>	TreeBin t = (TreeBin)fk;
1146	>	boolean validated = false;
1147	>	boolean deleted = false;
1148	>	t.acquire(0);
1149	>	try {
1150	>	if (tabAt(tab, i) == f) {
1151	>	validated = true;
1152	>	TreeNode p = t.getTreeNode(h, k, t.root);
1153	>	if (p != null) {
1154	>	Object pv = p.val;
1155	>	if (cv == null || cv == pv || cv.equals(pv)) {
1156	>	oldVal = pv;
1157	>	if ((p.val = v) == null) {
1158	>	deleted = true;
1159	>	t.deleteTreeNode(p);
1160	>	}
1161	>	}
1162	>	}
1163	>	}
1164	>	} finally {
1165	>	t.release(0);
1166	>	}
1167	>	if (validated) {
1168	>	if (deleted)
1169	>	counter.add(-1L);
1170	>	break;
1171	>	}
1172	>	}
1173	>	else
1174	>	tab = (Node[])fk;
1175	>	}
1176	>	else if ((fh & HASH_BITS) != h && f.next == null) // precheck
1177	>	break;                          // rules out possible existence
1178	>	else if ((fh & LOCKED) != 0) {
1179	>	checkForResize();               // try resizing if can't get lock
1180	>	f.tryAwaitLock(tab, i);
1181	>	}
1182	>	else if (f.casHash(fh, fh | LOCKED)) {
1183	>	boolean validated = false;
1184	>	boolean deleted = false;
1185	>	try {
1186	>	if (tabAt(tab, i) == f) {
1187	>	validated = true;
1188	>	for (Node e = f, pred = null;;) {
1189	>	Object ek, ev;
1190	>	if ((e.hash & HASH_BITS) == h &&
1191	>	((ev = e.val) != null) &&
1192	>	((ek = e.key) == k || k.equals(ek))) {
1193	>	if (cv == null || cv == ev || cv.equals(ev)) {
1194	>	oldVal = ev;
1195	>	if ((e.val = v) == null) {
1196	>	deleted = true;
1197	>	Node en = e.next;
1198	>	if (pred != null)
1199	>	pred.next = en;
1200	>	else
1201	>	setTabAt(tab, i, en);
1202	>	}
1203	>	}
1204	>	break;
1205	>	}
1206	>	pred = e;
1207	>	if ((e = e.next) == null)
1208	>	break;
1209	>	}
1210	>	}
1211	>	} finally {
1212	>	if (!f.casHash(fh | LOCKED, fh)) {
1213	>	f.hash = fh;
1214	>	synchronized (f) { f.notifyAll(); };
1215	>	}
1216	>	}
1217	>	if (validated) {
1218	>	if (deleted)
1219	>	counter.add(-1L);
1220	>	break;
1221	>	}
1222	>	}
1223	>	}
1224	>	return oldVal;
1225	>	}
1226	>
1227	>	/*
1228	>	* Internal versions of the five insertion methods, each a
1229	>	* little more complicated than the last. All have
1230	>	* the same basic structure as the first (internalPut):
1231	>	*  1. If table uninitialized, create
1232	>	*  2. If bin empty, try to CAS new node
1233	>	*  3. If bin stale, use new table
1234	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1235	>	*  5. Lock and validate; if valid, scan and add or update
1236	>	*
1237	>	* The others interweave other checks and/or alternative actions:
1238	>	*  * Plain put checks for and performs resize after insertion.
1239	>	*  * putIfAbsent prescans for mapping without lock (and fails to add
1240	>	*    if present), which also makes pre-emptive resize checks worthwhile.
1241	>	*  * computeIfAbsent extends form used in putIfAbsent with additional
1242	>	*    mechanics to deal with, calls, potential exceptions and null
1243	>	*    returns from function call.
1244	>	*  * compute uses the same function-call mechanics, but without
1245	>	*    the prescans
1246	>	*  * putAll attempts to pre-allocate enough table space
1247	>	*    and more lazily performs count updates and checks.
1248	>	*
1249	>	* Someday when details settle down a bit more, it might be worth
1250	>	* some factoring to reduce sprawl.
1251	>	*/
1252	>
1253	>	/** Implementation for put */
1254	>	private final Object internalPut(Object k, Object v) {
1255		int h = spread(k.hashCode());
1256	<	Object oldVal = null;               // previous value or null if none
1256	>	int count = 0;
1257		for (Node[] tab = table;;) {
1258	<	Node e; int i; Object ek, ev;
1258	>	int i; Node f; int fh; Object fk;
1259		if (tab == null)
1260	<	tab = growTable();
1261	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1260	>	tab = initTable();
1261	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1262		if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1263		break;                   // no lock when adding to empty bin
1264		}
1265	<	else if (e.hash < 0)             // resized -- restart with new table
1266	<	tab = (Node[])e.key;
1267	<	else if (!replace && e.hash == h && (ev = e.val) != null &&
1268	<	((ek = e.key) == k || k.equals(ek))) {
1269	<	if (tabAt(tab, i) == e) {    // inspect and validate 1st node
1270	<	oldVal = ev;             // without lock for putIfAbsent
1271	<	break;
1265	>	else if ((fh = f.hash) == MOVED) {
1266	>	if ((fk = f.key) instanceof TreeBin) {
1267	>	TreeBin t = (TreeBin)fk;
1268	>	Object oldVal = null;
1269	>	t.acquire(0);
1270	>	try {
1271	>	if (tabAt(tab, i) == f) {
1272	>	count = 2;
1273	>	TreeNode p = t.putTreeNode(h, k, v);
1274	>	if (p != null) {
1275	>	oldVal = p.val;
1276	>	p.val = v;
1277	>	}
1278	>	}
1279	>	} finally {
1280	>	t.release(0);
1281	>	}
1282	>	if (count != 0) {
1283	>	if (oldVal != null)
1284	>	return oldVal;
1285	>	break;
1286	>	}
1287		}
1288	+	else
1289	+	tab = (Node[])fk;
1290		}
1291	<	else {
1292	<	boolean validated = false;
1293	<	boolean checkSize = false;
1294	<	synchronized (e) {           // lock the 1st node of bin list
1295	<	if (tabAt(tab, i) == e) {
1296	<	validated = true;    // retry if 1st already deleted
1297	<	for (Node first = e;;) {
1298	<	if (e.hash == h &&
1299	<	((ek = e.key) == k || k.equals(ek)) &&
1300	<	(ev = e.val) != null) {
1291	>	else if ((fh & LOCKED) != 0) {
1292	>	checkForResize();
1293	>	f.tryAwaitLock(tab, i);
1294	>	}
1295	>	else if (f.casHash(fh, fh | LOCKED)) {
1296	>	Object oldVal = null;
1297	>	try {                        // needed in case equals() throws
1298	>	if (tabAt(tab, i) == f) {
1299	>	count = 1;
1300	>	for (Node e = f;; ++count) {
1301	>	Object ek, ev;
1302	>	if ((e.hash & HASH_BITS) == h &&
1303	>	(ev = e.val) != null &&
1304	>	((ek = e.key) == k || k.equals(ek))) {
1305		oldVal = ev;
1306	<	if (replace)
558	<	e.val = v;
1306	>	e.val = v;
1307		break;
1308		}
1309		Node last = e;
1310		if ((e = e.next) == null) {
1311		last.next = new Node(h, k, v, null);
1312	<	if (last != first || tab.length <= 64)
1313	<	checkSize = true;
1312	>	if (count >= TREE_THRESHOLD)
1313	>	replaceWithTreeBin(tab, i, k);
1314		break;
1315		}
1316		}
1317		}
1318	+	} finally {                  // unlock and signal if needed
1319	+	if (!f.casHash(fh | LOCKED, fh)) {
1320	+	f.hash = fh;
1321	+	synchronized (f) { f.notifyAll(); };
1322	+	}
1323		}
1324	<	if (validated) {
1325	<	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
1326	<	resizing == 0 && counter.sum() >= (long)threshold)
1327	<	growTable();
1324	>	if (count != 0) {
1325	>	if (oldVal != null)
1326	>	return oldVal;
1327	>	if (tab.length <= 64)
1328	>	count = 2;
1329		break;
1330		}
1331		}
1332		}
1333	<	if (oldVal == null)
1334	<	counter.increment();             // update counter outside of locks
1335	<	return oldVal;
1333	>	counter.add(1L);
1334	>	if (count > 1)
1335	>	checkForResize();
1336	>	return null;
1337		}
1338
1339	<	/**
1340	<	* Implementation for the four public remove/replace methods:
586	<	* Replaces node value with v, conditional upon match of cv if
587	<	* non-null.  If resulting value is null, delete.
588	<	*/
589	<	private final Object internalReplace(Object k, Object v, Object cv) {
1339	>	/** Implementation for putIfAbsent */
1340	>	private final Object internalPutIfAbsent(Object k, Object v) {
1341		int h = spread(k.hashCode());
1342	+	int count = 0;
1343		for (Node[] tab = table;;) {
1344	<	Node e; int i;
1345	<	if (tab == null ||
1346	<	(e = tabAt(tab, i = (tab.length - 1) & h)) == null)
1347	<	return null;
1348	<	else if (e.hash < 0)
1349	<	tab = (Node[])e.key;
1344	>	int i; Node f; int fh; Object fk, fv;
1345	>	if (tab == null)
1346	>	tab = initTable();
1347	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1348	>	if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1349	>	break;
1350	>	}
1351	>	else if ((fh = f.hash) == MOVED) {
1352	>	if ((fk = f.key) instanceof TreeBin) {
1353	>	TreeBin t = (TreeBin)fk;
1354	>	Object oldVal = null;
1355	>	t.acquire(0);
1356	>	try {
1357	>	if (tabAt(tab, i) == f) {
1358	>	count = 2;
1359	>	TreeNode p = t.putTreeNode(h, k, v);
1360	>	if (p != null)
1361	>	oldVal = p.val;
1362	>	}
1363	>	} finally {
1364	>	t.release(0);
1365	>	}
1366	>	if (count != 0) {
1367	>	if (oldVal != null)
1368	>	return oldVal;
1369	>	break;
1370	>	}
1371	>	}
1372	>	else
1373	>	tab = (Node[])fk;
1374	>	}
1375	>	else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1376	>	((fk = f.key) == k || k.equals(fk)))
1377	>	return fv;
1378		else {
1379	<	Object oldVal = null;
1380	<	boolean validated = false;
1381	<	boolean deleted = false;
1382	<	synchronized (e) {
1383	<	if (tabAt(tab, i) == e) {
1384	<	validated = true;
1385	<	Node pred = null;
1386	<	do {
1387	<	Object ek, ev;
1388	<	if (e.hash == h &&
1389	<	((ek = e.key) == k || k.equals(ek)) &&
1390	<	((ev = e.val) != null)) {
1391	<	if (cv == null || cv == ev || cv.equals(ev)) {
1379	>	Node g = f.next;
1380	>	if (g != null) { // at least 2 nodes -- search and maybe resize
1381	>	for (Node e = g;;) {
1382	>	Object ek, ev;
1383	>	if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1384	>	((ek = e.key) == k || k.equals(ek)))
1385	>	return ev;
1386	>	if ((e = e.next) == null) {
1387	>	checkForResize();
1388	>	break;
1389	>	}
1390	>	}
1391	>	}
1392	>	if (((fh = f.hash) & LOCKED) != 0) {
1393	>	checkForResize();
1394	>	f.tryAwaitLock(tab, i);
1395	>	}
1396	>	else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1397	>	Object oldVal = null;
1398	>	try {
1399	>	if (tabAt(tab, i) == f) {
1400	>	count = 1;
1401	>	for (Node e = f;; ++count) {
1402	>	Object ek, ev;
1403	>	if ((e.hash & HASH_BITS) == h &&
1404	>	(ev = e.val) != null &&
1405	>	((ek = e.key) == k || k.equals(ek))) {
1406		oldVal = ev;
1407	<	if ((e.val = v) == null) {
1408	<	deleted = true;
1409	<	Node en = e.next;
1410	<	if (pred != null)
1411	<	pred.next = en;
1412	<	else
1413	<	setTabAt(tab, i, en);
1414	<	}
1407	>	break;
1408	>	}
1409	>	Node last = e;
1410	>	if ((e = e.next) == null) {
1411	>	last.next = new Node(h, k, v, null);
1412	>	if (count >= TREE_THRESHOLD)
1413	>	replaceWithTreeBin(tab, i, k);
1414	>	break;
1415		}
622	–	break;
1416		}
1417	<	} while ((e = (pred = e).next) != null);
1417	>	}
1418	>	} finally {
1419	>	if (!f.casHash(fh | LOCKED, fh)) {
1420	>	f.hash = fh;
1421	>	synchronized (f) { f.notifyAll(); };
1422	>	}
1423	>	}
1424	>	if (count != 0) {
1425	>	if (oldVal != null)
1426	>	return oldVal;
1427	>	if (tab.length <= 64)
1428	>	count = 2;
1429	>	break;
1430		}
626	–	}
627	–	if (validated) {
628	–	if (deleted)
629	–	counter.decrement();
630	–	return oldVal;
1431		}
1432		}
1433		}
1434	+	counter.add(1L);
1435	+	if (count > 1)
1436	+	checkForResize();
1437	+	return null;
1438		}
1439
1440	<	/** Implementation for computeIfAbsent and compute. Like put, but messier. */
1441	<	@SuppressWarnings("unchecked")
1442	<	private final V internalCompute(K k,
639	<	MappingFunction<? super K, ? extends V> f,
640	<	boolean replace) {
1440	>	/** Implementation for computeIfAbsent */
1441	>	private final Object internalComputeIfAbsent(K k,
1442	>	MappingFunction<? super K, ?> mf) {
1443		int h = spread(k.hashCode());
1444	<	V val = null;
1445	<	boolean added = false;
1446	<	Node[] tab = table;
1447	<	outer:for (;;) {
646	<	Node e; int i; Object ek, ev;
1444	>	Object val = null;
1445	>	int count = 0;
1446	>	for (Node[] tab = table;;) {
1447	>	Node f; int i, fh; Object fk, fv;
1448		if (tab == null)
1449	<	tab = growTable();
1450	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1451	<	Node node = new Node(h, k, null, null);
1452	<	boolean validated = false;
1453	<	synchronized (node) {  // must lock while computing value
1454	<	if (casTabAt(tab, i, null, node)) {
1455	<	validated = true;
1456	<	try {
1457	<	val = f.map(k);
1458	<	if (val != null) {
1459	<	node.val = val;
1449	>	tab = initTable();
1450	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1451	>	Node node = new Node(fh = h | LOCKED, k, null, null);
1452	>	if (casTabAt(tab, i, null, node)) {
1453	>	count = 1;
1454	>	try {
1455	>	if ((val = mf.map(k)) != null)
1456	>	node.val = val;
1457	>	} finally {
1458	>	if (val == null)
1459	>	setTabAt(tab, i, null);
1460	>	if (!node.casHash(fh, h)) {
1461	>	node.hash = h;
1462	>	synchronized (node) { node.notifyAll(); };
1463	>	}
1464	>	}
1465	>	}
1466	>	if (count != 0)
1467	>	break;
1468	>	}
1469	>	else if ((fh = f.hash) == MOVED) {
1470	>	if ((fk = f.key) instanceof TreeBin) {
1471	>	TreeBin t = (TreeBin)fk;
1472	>	boolean added = false;
1473	>	t.acquire(0);
1474	>	try {
1475	>	if (tabAt(tab, i) == f) {
1476	>	count = 1;
1477	>	TreeNode p = t.getTreeNode(h, k, t.root);
1478	>	if (p != null)
1479	>	val = p.val;
1480	>	else if ((val = mf.map(k)) != null) {
1481		added = true;
1482	+	count = 2;
1483	+	t.putTreeNode(h, k, val);
1484		}
661	–	} finally {
662	–	if (!added)
663	–	setTabAt(tab, i, null);
1485		}
1486	+	} finally {
1487	+	t.release(0);
1488	+	}
1489	+	if (count != 0) {
1490	+	if (!added)
1491	+	return val;
1492	+	break;
1493		}
1494		}
1495	<	if (validated)
1496	<	break;
1495	>	else
1496	>	tab = (Node[])fk;
1497		}
1498	<	else if (e.hash < 0)
1499	<	tab = (Node[])e.key;
1500	<	else if (!replace && e.hash == h && (ev = e.val) != null &&
1501	<	((ek = e.key) == k || k.equals(ek))) {
1502	<	if (tabAt(tab, i) == e) {
1503	<	val = (V)ev;
1498	>	else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1499	>	((fk = f.key) == k || k.equals(fk)))
1500	>	return fv;
1501	>	else {
1502	>	Node g = f.next;
1503	>	if (g != null) {
1504	>	for (Node e = g;;) {
1505	>	Object ek, ev;
1506	>	if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1507	>	((ek = e.key) == k || k.equals(ek)))
1508	>	return ev;
1509	>	if ((e = e.next) == null) {
1510	>	checkForResize();
1511	>	break;
1512	>	}
1513	>	}
1514	>	}
1515	>	if (((fh = f.hash) & LOCKED) != 0) {
1516	>	checkForResize();
1517	>	f.tryAwaitLock(tab, i);
1518	>	}
1519	>	else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1520	>	boolean added = false;
1521	>	try {
1522	>	if (tabAt(tab, i) == f) {
1523	>	count = 1;
1524	>	for (Node e = f;; ++count) {
1525	>	Object ek, ev;
1526	>	if ((e.hash & HASH_BITS) == h &&
1527	>	(ev = e.val) != null &&
1528	>	((ek = e.key) == k || k.equals(ek))) {
1529	>	val = ev;
1530	>	break;
1531	>	}
1532	>	Node last = e;
1533	>	if ((e = e.next) == null) {
1534	>	if ((val = mf.map(k)) != null) {
1535	>	added = true;
1536	>	last.next = new Node(h, k, val, null);
1537	>	if (count >= TREE_THRESHOLD)
1538	>	replaceWithTreeBin(tab, i, k);
1539	>	}
1540	>	break;
1541	>	}
1542	>	}
1543	>	}
1544	>	} finally {
1545	>	if (!f.casHash(fh | LOCKED, fh)) {
1546	>	f.hash = fh;
1547	>	synchronized (f) { f.notifyAll(); };
1548	>	}
1549	>	}
1550	>	if (count != 0) {
1551	>	if (!added)
1552	>	return val;
1553	>	if (tab.length <= 64)
1554	>	count = 2;
1555	>	break;
1556	>	}
1557	>	}
1558	>	}
1559	>	}
1560	>	if (val != null) {
1561	>	counter.add(1L);
1562	>	if (count > 1)
1563	>	checkForResize();
1564	>	}
1565	>	return val;
1566	>	}
1567	>
1568	>	/** Implementation for compute */
1569	>	@SuppressWarnings("unchecked")
1570	>	private final Object internalCompute(K k,
1571	>	RemappingFunction<? super K, V> mf) {
1572	>	int h = spread(k.hashCode());
1573	>	Object val = null;
1574	>	int delta = 0;
1575	>	int count = 0;
1576	>	for (Node[] tab = table;;) {
1577	>	Node f; int i, fh; Object fk;
1578	>	if (tab == null)
1579	>	tab = initTable();
1580	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1581	>	Node node = new Node(fh = h | LOCKED, k, null, null);
1582	>	if (casTabAt(tab, i, null, node)) {
1583	>	try {
1584	>	count = 1;
1585	>	if ((val = mf.remap(k, null)) != null) {
1586	>	node.val = val;
1587	>	delta = 1;
1588	>	}
1589	>	} finally {
1590	>	if (delta == 0)
1591	>	setTabAt(tab, i, null);
1592	>	if (!node.casHash(fh, h)) {
1593	>	node.hash = h;
1594	>	synchronized (node) { node.notifyAll(); };
1595	>	}
1596	>	}
1597	>	}
1598	>	if (count != 0)
1599		break;
1600	+	}
1601	+	else if ((fh = f.hash) == MOVED) {
1602	+	if ((fk = f.key) instanceof TreeBin) {
1603	+	TreeBin t = (TreeBin)fk;
1604	+	t.acquire(0);
1605	+	try {
1606	+	if (tabAt(tab, i) == f) {
1607	+	count = 1;
1608	+	TreeNode p = t.getTreeNode(h, k, t.root);
1609	+	Object pv = (p == null) ? null : p.val;
1610	+	if ((val = mf.remap(k, (V)pv)) != null) {
1611	+	if (p != null)
1612	+	p.val = val;
1613	+	else {
1614	+	count = 2;
1615	+	delta = 1;
1616	+	t.putTreeNode(h, k, val);
1617	+	}
1618	+	}
1619	+	else if (p != null) {
1620	+	delta = -1;
1621	+	t.deleteTreeNode(p);
1622	+	}
1623	+	}
1624	+	} finally {
1625	+	t.release(0);
1626	+	}
1627	+	if (count != 0)
1628	+	break;
1629		}
1630	+	else
1631	+	tab = (Node[])fk;
1632		}
1633	<	else if (Thread.holdsLock(e))
1634	<	throw new IllegalStateException("Recursive map computation");
1635	<	else {
1636	<	boolean validated = false;
1637	<	boolean checkSize = false;
1638	<	synchronized (e) {
1639	<	if (tabAt(tab, i) == e) {
1640	<	validated = true;
1641	<	for (Node first = e;;) {
1642	<	if (e.hash == h &&
1643	<	((ek = e.key) == k || k.equals(ek)) &&
1644	<	((ev = e.val) != null)) {
1645	<	Object fv;
1646	<	if (replace && (fv = f.map(k)) != null)
1647	<	ev = e.val = fv;
1648	<	val = (V)ev;
1633	>	else if ((fh & LOCKED) != 0) {
1634	>	checkForResize();
1635	>	f.tryAwaitLock(tab, i);
1636	>	}
1637	>	else if (f.casHash(fh, fh | LOCKED)) {
1638	>	try {
1639	>	if (tabAt(tab, i) == f) {
1640	>	count = 1;
1641	>	for (Node e = f, pred = null;; ++count) {
1642	>	Object ek, ev;
1643	>	if ((e.hash & HASH_BITS) == h &&
1644	>	(ev = e.val) != null &&
1645	>	((ek = e.key) == k || k.equals(ek))) {
1646	>	val = mf.remap(k, (V)ev);
1647	>	if (val != null)
1648	>	e.val = val;
1649	>	else {
1650	>	delta = -1;
1651	>	Node en = e.next;
1652	>	if (pred != null)
1653	>	pred.next = en;
1654	>	else
1655	>	setTabAt(tab, i, en);
1656	>	}
1657		break;
1658		}
1659	<	Node last = e;
1659	>	pred = e;
1660		if ((e = e.next) == null) {
1661	<	if ((val = f.map(k)) != null) {
1662	<	last.next = new Node(h, k, val, null);
1663	<	added = true;
1664	<	if (last != first || tab.length <= 64)
1665	<	checkSize = true;
1661	>	if ((val = mf.remap(k, null)) != null) {
1662	>	pred.next = new Node(h, k, val, null);
1663	>	delta = 1;
1664	>	if (count >= TREE_THRESHOLD)
1665	>	replaceWithTreeBin(tab, i, k);
1666		}
1667		break;
1668		}
1669		}
1670		}
1671	+	} finally {
1672	+	if (!f.casHash(fh | LOCKED, fh)) {
1673	+	f.hash = fh;
1674	+	synchronized (f) { f.notifyAll(); };
1675	+	}
1676		}
1677	<	if (validated) {
1678	<	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
1679	<	resizing == 0 && counter.sum() >= (long)threshold)
713	<	growTable();
1677	>	if (count != 0) {
1678	>	if (tab.length <= 64)
1679	>	count = 2;
1680		break;
1681		}
1682		}
1683		}
1684	<	if (added)
1685	<	counter.increment();
1684	>	if (delta != 0) {
1685	>	counter.add((long)delta);
1686	>	if (count > 1)
1687	>	checkForResize();
1688	>	}
1689		return val;
1690		}
1691
1692	+	/** Implementation for putAll */
1693	+	private final void internalPutAll(Map<?, ?> m) {
1694	+	tryPresize(m.size());
1695	+	long delta = 0L;     // number of uncommitted additions
1696	+	boolean npe = false; // to throw exception on exit for nulls
1697	+	try {                // to clean up counts on other exceptions
1698	+	for (Map.Entry<?, ?> entry : m.entrySet()) {
1699	+	Object k, v;
1700	+	if (entry == null || (k = entry.getKey()) == null ||
1701	+	(v = entry.getValue()) == null) {
1702	+	npe = true;
1703	+	break;
1704	+	}
1705	+	int h = spread(k.hashCode());
1706	+	for (Node[] tab = table;;) {
1707	+	int i; Node f; int fh; Object fk;
1708	+	if (tab == null)
1709	+	tab = initTable();
1710	+	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1711	+	if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1712	+	++delta;
1713	+	break;
1714	+	}
1715	+	}
1716	+	else if ((fh = f.hash) == MOVED) {
1717	+	if ((fk = f.key) instanceof TreeBin) {
1718	+	TreeBin t = (TreeBin)fk;
1719	+	boolean validated = false;
1720	+	t.acquire(0);
1721	+	try {
1722	+	if (tabAt(tab, i) == f) {
1723	+	validated = true;
1724	+	TreeNode p = t.getTreeNode(h, k, t.root);
1725	+	if (p != null)
1726	+	p.val = v;
1727	+	else {
1728	+	t.putTreeNode(h, k, v);
1729	+	++delta;
1730	+	}
1731	+	}
1732	+	} finally {
1733	+	t.release(0);
1734	+	}
1735	+	if (validated)
1736	+	break;
1737	+	}
1738	+	else
1739	+	tab = (Node[])fk;
1740	+	}
1741	+	else if ((fh & LOCKED) != 0) {
1742	+	counter.add(delta);
1743	+	delta = 0L;
1744	+	checkForResize();
1745	+	f.tryAwaitLock(tab, i);
1746	+	}
1747	+	else if (f.casHash(fh, fh | LOCKED)) {
1748	+	int count = 0;
1749	+	try {
1750	+	if (tabAt(tab, i) == f) {
1751	+	count = 1;
1752	+	for (Node e = f;; ++count) {
1753	+	Object ek, ev;
1754	+	if ((e.hash & HASH_BITS) == h &&
1755	+	(ev = e.val) != null &&
1756	+	((ek = e.key) == k || k.equals(ek))) {
1757	+	e.val = v;
1758	+	break;
1759	+	}
1760	+	Node last = e;
1761	+	if ((e = e.next) == null) {
1762	+	++delta;
1763	+	last.next = new Node(h, k, v, null);
1764	+	if (count >= TREE_THRESHOLD)
1765	+	replaceWithTreeBin(tab, i, k);
1766	+	break;
1767	+	}
1768	+	}
1769	+	}
1770	+	} finally {
1771	+	if (!f.casHash(fh | LOCKED, fh)) {
1772	+	f.hash = fh;
1773	+	synchronized (f) { f.notifyAll(); };
1774	+	}
1775	+	}
1776	+	if (count != 0) {
1777	+	if (count > 1) {
1778	+	counter.add(delta);
1779	+	delta = 0L;
1780	+	checkForResize();
1781	+	}
1782	+	break;
1783	+	}
1784	+	}
1785	+	}
1786	+	}
1787	+	} finally {
1788	+	if (delta != 0)
1789	+	counter.add(delta);
1790	+	}
1791	+	if (npe)
1792	+	throw new NullPointerException();
1793	+	}
1794	+
1795	+	/* ---------------- Table Initialization and Resizing -------------- */
1796	+
1797		/**
1798	<	* Implementation for clear. Steps through each bin, removing all nodes.
1798	>	* Returns a power of two table size for the given desired capacity.
1799	>	* See Hackers Delight, sec 3.2
1800	>	*/
1801	>	private static final int tableSizeFor(int c) {
1802	>	int n = c - 1;
1803	>	n |= n >>> 1;
1804	>	n |= n >>> 2;
1805	>	n |= n >>> 4;
1806	>	n |= n >>> 8;
1807	>	n |= n >>> 16;
1808	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1809	>	}
1810	>
1811	>	/**
1812	>	* Initializes table, using the size recorded in sizeCtl.
1813	>	*/
1814	>	private final Node[] initTable() {
1815	>	Node[] tab; int sc;
1816	>	while ((tab = table) == null) {
1817	>	if ((sc = sizeCtl) < 0)
1818	>	Thread.yield(); // lost initialization race; just spin
1819	>	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1820	>	try {
1821	>	if ((tab = table) == null) {
1822	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1823	>	tab = table = new Node[n];
1824	>	sc = n - (n >>> 2);
1825	>	}
1826	>	} finally {
1827	>	sizeCtl = sc;
1828	>	}
1829	>	break;
1830	>	}
1831	>	}
1832	>	return tab;
1833	>	}
1834	>
1835	>	/**
1836	>	* If table is too small and not already resizing, creates next
1837	>	* table and transfers bins.  Rechecks occupancy after a transfer
1838	>	* to see if another resize is already needed because resizings
1839	>	* are lagging additions.
1840	>	*/
1841	>	private final void checkForResize() {
1842	>	Node[] tab; int n, sc;
1843	>	while ((tab = table) != null &&
1844	>	(n = tab.length) < MAXIMUM_CAPACITY &&
1845	>	(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
1846	>	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1847	>	try {
1848	>	if (tab == table) {
1849	>	table = rebuild(tab);
1850	>	sc = (n << 1) - (n >>> 1);
1851	>	}
1852	>	} finally {
1853	>	sizeCtl = sc;
1854	>	}
1855	>	}
1856	>	}
1857	>
1858	>	/**
1859	>	* Tries to presize table to accommodate the given number of elements.
1860	>	*
1861	>	* @param size number of elements (doesn't need to be perfectly accurate)
1862	>	*/
1863	>	private final void tryPresize(int size) {
1864	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1865	>	tableSizeFor(size + (size >>> 1) + 1);
1866	>	int sc;
1867	>	while ((sc = sizeCtl) >= 0) {
1868	>	Node[] tab = table; int n;
1869	>	if (tab == null || (n = tab.length) == 0) {
1870	>	n = (sc > c) ? sc : c;
1871	>	if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1872	>	try {
1873	>	if (table == tab) {
1874	>	table = new Node[n];
1875	>	sc = n - (n >>> 2);
1876	>	}
1877	>	} finally {
1878	>	sizeCtl = sc;
1879	>	}
1880	>	}
1881	>	}
1882	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1883	>	break;
1884	>	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1885	>	try {
1886	>	if (table == tab) {
1887	>	table = rebuild(tab);
1888	>	sc = (n << 1) - (n >>> 1);
1889	>	}
1890	>	} finally {
1891	>	sizeCtl = sc;
1892	>	}
1893	>	}
1894	>	}
1895	>	}
1896	>
1897	>	/*
1898	>	* Moves and/or copies the nodes in each bin to new table. See
1899	>	* above for explanation.
1900	>	*
1901	>	* @return the new table
1902	>	*/
1903	>	private static final Node[] rebuild(Node[] tab) {
1904	>	int n = tab.length;
1905	>	Node[] nextTab = new Node[n << 1];
1906	>	Node fwd = new Node(MOVED, nextTab, null, null);
1907	>	int[] buffer = null;       // holds bins to revisit; null until needed
1908	>	Node rev = null;           // reverse forwarder; null until needed
1909	>	int nbuffered = 0;         // the number of bins in buffer list
1910	>	int bufferIndex = 0;       // buffer index of current buffered bin
1911	>	int bin = n - 1;           // current non-buffered bin or -1 if none
1912	>
1913	>	for (int i = bin;;) {      // start upwards sweep
1914	>	int fh; Node f;
1915	>	if ((f = tabAt(tab, i)) == null) {
1916	>	if (bin >= 0) {    // no lock needed (or available)
1917	>	if (!casTabAt(tab, i, f, fwd))
1918	>	continue;
1919	>	}
1920	>	else {             // transiently use a locked forwarding node
1921	>	Node g = new Node(MOVED|LOCKED, nextTab, null, null);
1922	>	if (!casTabAt(tab, i, f, g))
1923	>	continue;
1924	>	setTabAt(nextTab, i, null);
1925	>	setTabAt(nextTab, i + n, null);
1926	>	setTabAt(tab, i, fwd);
1927	>	if (!g.casHash(MOVED|LOCKED, MOVED)) {
1928	>	g.hash = MOVED;
1929	>	synchronized (g) { g.notifyAll(); }
1930	>	}
1931	>	}
1932	>	}
1933	>	else if ((fh = f.hash) == MOVED) {
1934	>	Object fk = f.key;
1935	>	if (fk instanceof TreeBin) {
1936	>	TreeBin t = (TreeBin)fk;
1937	>	boolean validated = false;
1938	>	t.acquire(0);
1939	>	try {
1940	>	if (tabAt(tab, i) == f) {
1941	>	validated = true;
1942	>	splitTreeBin(nextTab, i, t);
1943	>	setTabAt(tab, i, fwd);
1944	>	}
1945	>	} finally {
1946	>	t.release(0);
1947	>	}
1948	>	if (!validated)
1949	>	continue;
1950	>	}
1951	>	}
1952	>	else if ((fh & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
1953	>	boolean validated = false;
1954	>	try {              // split to lo and hi lists; copying as needed
1955	>	if (tabAt(tab, i) == f) {
1956	>	validated = true;
1957	>	splitBin(nextTab, i, f);
1958	>	setTabAt(tab, i, fwd);
1959	>	}
1960	>	} finally {
1961	>	if (!f.casHash(fh | LOCKED, fh)) {
1962	>	f.hash = fh;
1963	>	synchronized (f) { f.notifyAll(); };
1964	>	}
1965	>	}
1966	>	if (!validated)
1967	>	continue;
1968	>	}
1969	>	else {
1970	>	if (buffer == null) // initialize buffer for revisits
1971	>	buffer = new int[TRANSFER_BUFFER_SIZE];
1972	>	if (bin < 0 && bufferIndex > 0) {
1973	>	int j = buffer[--bufferIndex];
1974	>	buffer[bufferIndex] = i;
1975	>	i = j;         // swap with another bin
1976	>	continue;
1977	>	}
1978	>	if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
1979	>	f.tryAwaitLock(tab, i);
1980	>	continue;      // no other options -- block
1981	>	}
1982	>	if (rev == null)   // initialize reverse-forwarder
1983	>	rev = new Node(MOVED, tab, null, null);
1984	>	if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
1985	>	continue;      // recheck before adding to list
1986	>	buffer[nbuffered++] = i;
1987	>	setTabAt(nextTab, i, rev);     // install place-holders
1988	>	setTabAt(nextTab, i + n, rev);
1989	>	}
1990	>
1991	>	if (bin > 0)
1992	>	i = --bin;
1993	>	else if (buffer != null && nbuffered > 0) {
1994	>	bin = -1;
1995	>	i = buffer[bufferIndex = --nbuffered];
1996	>	}
1997	>	else
1998	>	return nextTab;
1999	>	}
2000	>	}
2001	>
2002	>	/**
2003	>	* Splits a normal bin with list headed by e into lo and hi parts;
2004	>	* installs in given table.
2005	>	*/
2006	>	private static void splitBin(Node[] nextTab, int i, Node e) {
2007	>	int bit = nextTab.length >>> 1; // bit to split on
2008	>	int runBit = e.hash & bit;
2009	>	Node lastRun = e, lo = null, hi = null;
2010	>	for (Node p = e.next; p != null; p = p.next) {
2011	>	int b = p.hash & bit;
2012	>	if (b != runBit) {
2013	>	runBit = b;
2014	>	lastRun = p;
2015	>	}
2016	>	}
2017	>	if (runBit == 0)
2018	>	lo = lastRun;
2019	>	else
2020	>	hi = lastRun;
2021	>	for (Node p = e; p != lastRun; p = p.next) {
2022	>	int ph = p.hash & HASH_BITS;
2023	>	Object pk = p.key, pv = p.val;
2024	>	if ((ph & bit) == 0)
2025	>	lo = new Node(ph, pk, pv, lo);
2026	>	else
2027	>	hi = new Node(ph, pk, pv, hi);
2028	>	}
2029	>	setTabAt(nextTab, i, lo);
2030	>	setTabAt(nextTab, i + bit, hi);
2031	>	}
2032	>
2033	>	/**
2034	>	* Splits a tree bin into lo and hi parts; installs in given table.
2035	>	*/
2036	>	private static void splitTreeBin(Node[] nextTab, int i, TreeBin t) {
2037	>	int bit = nextTab.length >>> 1;
2038	>	TreeBin lt = new TreeBin();
2039	>	TreeBin ht = new TreeBin();
2040	>	int lc = 0, hc = 0;
2041	>	for (Node e = t.first; e != null; e = e.next) {
2042	>	int h = e.hash & HASH_BITS;
2043	>	Object k = e.key, v = e.val;
2044	>	if ((h & bit) == 0) {
2045	>	++lc;
2046	>	lt.putTreeNode(h, k, v);
2047	>	}
2048	>	else {
2049	>	++hc;
2050	>	ht.putTreeNode(h, k, v);
2051	>	}
2052	>	}
2053	>	Node ln, hn; // throw away trees if too small
2054	>	if (lc <= (TREE_THRESHOLD >>> 1)) {
2055	>	ln = null;
2056	>	for (Node p = lt.first; p != null; p = p.next)
2057	>	ln = new Node(p.hash, p.key, p.val, ln);
2058	>	}
2059	>	else
2060	>	ln = new Node(MOVED, lt, null, null);
2061	>	setTabAt(nextTab, i, ln);
2062	>	if (hc <= (TREE_THRESHOLD >>> 1)) {
2063	>	hn = null;
2064	>	for (Node p = ht.first; p != null; p = p.next)
2065	>	hn = new Node(p.hash, p.key, p.val, hn);
2066	>	}
2067	>	else
2068	>	hn = new Node(MOVED, ht, null, null);
2069	>	setTabAt(nextTab, i + bit, hn);
2070	>	}
2071	>
2072	>	/**
2073	>	* Implementation for clear. Steps through each bin, removing all
2074	>	* nodes.
2075		*/
2076		private final void internalClear() {
2077		long delta = 0L; // negative number of deletions
2078		int i = 0;
2079		Node[] tab = table;
2080		while (tab != null && i < tab.length) {
2081	<	Node e = tabAt(tab, i);
2082	<	if (e == null)
2081	>	int fh; Object fk;
2082	>	Node f = tabAt(tab, i);
2083	>	if (f == null)
2084		++i;
2085	<	else if (e.hash < 0)
2086	<	tab = (Node[])e.key;
2087	<	else {
2088	<	boolean validated = false;
2089	<	synchronized (e) {
2090	<	if (tabAt(tab, i) == e) {
2091	<	validated = true;
2092	<	Node en;
742	<	do {
743	<	en = e.next;
744	<	if (e.val != null) { // currently always true
745	<	e.val = null;
2085	>	else if ((fh = f.hash) == MOVED) {
2086	>	if ((fk = f.key) instanceof TreeBin) {
2087	>	TreeBin t = (TreeBin)fk;
2088	>	t.acquire(0);
2089	>	try {
2090	>	if (tabAt(tab, i) == f) {
2091	>	for (Node p = t.first; p != null; p = p.next) {
2092	>	p.val = null;
2093		--delta;
2094		}
2095	<	} while ((e = en) != null);
2095	>	t.first = null;
2096	>	t.root = null;
2097	>	++i;
2098	>	}
2099	>	} finally {
2100	>	t.release(0);
2101	>	}
2102	>	}
2103	>	else
2104	>	tab = (Node[])fk;
2105	>	}
2106	>	else if ((fh & LOCKED) != 0) {
2107	>	counter.add(delta); // opportunistically update count
2108	>	delta = 0L;
2109	>	f.tryAwaitLock(tab, i);
2110	>	}
2111	>	else if (f.casHash(fh, fh | LOCKED)) {
2112	>	try {
2113	>	if (tabAt(tab, i) == f) {
2114	>	for (Node e = f; e != null; e = e.next) {
2115	>	e.val = null;
2116	>	--delta;
2117	>	}
2118		setTabAt(tab, i, null);
2119	+	++i;
2120	+	}
2121	+	} finally {
2122	+	if (!f.casHash(fh | LOCKED, fh)) {
2123	+	f.hash = fh;
2124	+	synchronized (f) { f.notifyAll(); };
2125		}
2126		}
752	–	if (validated)
753	–	++i;
2127		}
2128		}
2129	<	counter.add(delta);
2129	>	if (delta != 0)
2130	>	counter.add(delta);
2131		}
2132
2133		/* ----------------Table Traversal -------------- */
#	Line 764 | Line 2138 | public class ConcurrentHashMapV8<K, V>
2138		*
2139		* At each step, the iterator snapshots the key ("nextKey") and
2140		* value ("nextVal") of a valid node (i.e., one that, at point of
2141	<	* snapshot, has a nonnull user value). Because val fields can
2141	>	* snapshot, has a non-null user value). Because val fields can
2142		* change (including to null, indicating deletion), field nextVal
2143		* might not be accurate at point of use, but still maintains the
2144		* weak consistency property of holding a value that was once
2145		* valid.
2146		*
2147		* Internal traversals directly access these fields, as in:
2148	<	* {@code while (it.next != null) { process(nextKey); it.advance(); }}
2148	>	* {@code while (it.advance() != null) { process(it.nextKey); }}
2149		*
2150	<	* Exported iterators (subclasses of ViewIterator) extract key,
2151	<	* value, or key-value pairs as return values of Iterator.next(),
2152	<	* and encapulate the it.next check as hasNext();
2153	<	*
2154	<	* The iterator visits each valid node that was reachable upon
2155	<	* iterator construction once. It might miss some that were added
2156	<	* to a bin after the bin was visited, which is OK wrt consistency
2157	<	* guarantees. Maintaining this property in the face of possible
2158	<	* ongoing resizes requires a fair amount of bookkeeping state
2159	<	* that is difficult to optimize away amidst volatile accesses.
2160	<	* Even so, traversal maintains reasonable throughput.
2150	>	* Exported iterators must track whether the iterator has advanced
2151	>	* (in hasNext vs next) (by setting/checking/nulling field
2152	>	* nextVal), and then extract key, value, or key-value pairs as
2153	>	* return values of next().
2154	>	*
2155	>	* The iterator visits once each still-valid node that was
2156	>	* reachable upon iterator construction. It might miss some that
2157	>	* were added to a bin after the bin was visited, which is OK wrt
2158	>	* consistency guarantees. Maintaining this property in the face
2159	>	* of possible ongoing resizes requires a fair amount of
2160	>	* bookkeeping state that is difficult to optimize away amidst
2161	>	* volatile accesses.  Even so, traversal maintains reasonable
2162	>	* throughput.
2163		*
2164		* Normally, iteration proceeds bin-by-bin traversing lists.
2165		* However, if the table has been resized, then all future steps
#	Line 792 | Line 2168 | public class ConcurrentHashMapV8<K, V>
2168		* paranoically cope with potential sharing by users of iterators
2169		* across threads, iteration terminates if a bounds checks fails
2170		* for a table read.
795	–	*
796	–	* The range-based constructor enables creation of parallel
797	–	* range-splitting traversals. (Not yet implemented.)
2171		*/
2172	<	static class InternalIterator {
2172	>	static class InternalIterator<K,V> {
2173	>	final ConcurrentHashMapV8<K, V> map;
2174		Node next;           // the next entry to use
2175		Node last;           // the last entry used
2176		Object nextKey;      // cached key field of next
#	Line 804 | Line 2178 | public class ConcurrentHashMapV8<K, V>
2178		Node[] tab;          // current table; updated if resized
2179		int index;           // index of bin to use next
2180		int baseIndex;       // current index of initial table
2181	<	final int baseLimit; // index bound for initial table
2181	>	int baseLimit;       // index bound for initial table
2182		final int baseSize;  // initial table size
2183
2184		/** Creates iterator for all entries in the table. */
2185	<	InternalIterator(Node[] tab) {
2186	<	this.tab = tab;
2185	>	InternalIterator(ConcurrentHashMapV8<K, V> map) {
2186	>	this.tab = (this.map = map).table;
2187		baseLimit = baseSize = (tab == null) ? 0 : tab.length;
814	–	index = baseIndex = 0;
815	–	next = null;
816	–	advance();
817	–	}
818	–
819	–	/** Creates iterator for the given range of the table */
820	–	InternalIterator(Node[] tab, int lo, int hi) {
821	–	this.tab = tab;
822	–	baseSize = (tab == null) ? 0 : tab.length;
823	–	baseLimit = (hi <= baseSize) ? hi : baseSize;
824	–	index = baseIndex = lo;
825	–	next = null;
826	–	advance();
2188		}
2189
2190	<	/** Advances next. See above for explanation. */
2191	<	final void advance() {
2190	>	/** Creates iterator for clone() and split() methods */
2191	>	InternalIterator(InternalIterator<K,V> it, boolean split) {
2192	>	this.map = it.map;
2193	>	this.tab = it.tab;
2194	>	this.baseSize = it.baseSize;
2195	>	int lo = it.baseIndex;
2196	>	int hi = this.baseLimit = it.baseLimit;
2197	>	this.index = this.baseIndex =
2198	>	(split) ? (it.baseLimit = (lo + hi + 1) >>> 1) : lo;
2199	>	}
2200	>
2201	>	/**
2202	>	* Advances next; returns nextVal or null if terminated
2203	>	* See above for explanation.
2204	>	*/
2205	>	final Object advance() {
2206		Node e = last = next;
2207	+	Object ev = null;
2208		outer: do {
2209	<	if (e != null)                   // pass used or skipped node
2209	>	if (e != null)                  // advance past used/skipped node
2210		e = e.next;
2211	<	while (e == null) {              // get to next non-null bin
2212	<	Node[] t; int b, i, n;       // checks must use locals
2211	>	while (e == null) {             // get to next non-null bin
2212	>	Node[] t; int b, i, n; Object ek; // checks must use locals
2213		if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
2214		(t = tab) == null || i >= (n = t.length))
2215		break outer;
2216	<	else if ((e = tabAt(t, i)) != null && e.hash < 0)
2217	<	tab = (Node[])e.key;     // restarts due to null val
2218	<	else                         // visit upper slots if present
2219	<	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2216	>	else if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
2217	>	if ((ek = e.key) instanceof TreeBin)
2218	>	e = ((TreeBin)ek).first;
2219	>	else {
2220	>	tab = (Node[])ek;
2221	>	continue;           // restarts due to null val
2222	>	}
2223	>	}                           // visit upper slots if present
2224	>	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2225		}
2226		nextKey = e.key;
2227	<	} while ((nextVal = e.val) == null); // skip deleted or special nodes
2227	>	} while ((ev = e.val) == null);    // skip deleted or special nodes
2228		next = e;
2229	+	return nextVal = ev;
2230		}
2231	+
2232	+	public final void remove() {
2233	+	if (nextVal == null)
2234	+	advance();
2235	+	Node e = last;
2236	+	if (e == null)
2237	+	throw new IllegalStateException();
2238	+	last = null;
2239	+	map.remove(e.key);
2240	+	}
2241	+
2242	+	public final boolean hasNext() {
2243	+	return nextVal != null || advance() != null;
2244	+	}
2245	+
2246	+	public final boolean hasMoreElements() { return hasNext(); }
2247		}
2248
2249		/* ---------------- Public operations -------------- */
#	Line 855 | Line 2253 | public class ConcurrentHashMapV8<K, V>
2253		*/
2254		public ConcurrentHashMapV8() {
2255		this.counter = new LongAdder();
858	–	this.targetCapacity = DEFAULT_CAPACITY;
2256		}
2257
2258		/**
#	Line 866 | Line 2263 | public class ConcurrentHashMapV8<K, V>
2263		* @param initialCapacity The implementation performs internal
2264		* sizing to accommodate this many elements.
2265		* @throws IllegalArgumentException if the initial capacity of
2266	<	* elements is negative.
2266	>	* elements is negative
2267		*/
2268		public ConcurrentHashMapV8(int initialCapacity) {
2269		if (initialCapacity < 0)
#	Line 875 | Line 2272 | public class ConcurrentHashMapV8<K, V>
2272		MAXIMUM_CAPACITY :
2273		tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2274		this.counter = new LongAdder();
2275	<	this.targetCapacity = cap;
2275	>	this.sizeCtl = cap;
2276		}
2277
2278		/**
#	Line 885 | Line 2282 | public class ConcurrentHashMapV8<K, V>
2282		*/
2283		public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2284		this.counter = new LongAdder();
2285	<	this.targetCapacity = DEFAULT_CAPACITY;
2286	<	putAll(m);
2285	>	this.sizeCtl = DEFAULT_CAPACITY;
2286	>	internalPutAll(m);
2287		}
2288
2289		/**
#	Line 898 | Line 2295 | public class ConcurrentHashMapV8<K, V>
2295		* performs internal sizing to accommodate this many elements,
2296		* given the specified load factor.
2297		* @param loadFactor the load factor (table density) for
2298	<	* establishing the initial table size.
2298	>	* establishing the initial table size
2299		* @throws IllegalArgumentException if the initial capacity of
2300		* elements is negative or the load factor is nonpositive
2301		*
#	Line 918 | Line 2315 | public class ConcurrentHashMapV8<K, V>
2315		* performs internal sizing to accommodate this many elements,
2316		* given the specified load factor.
2317		* @param loadFactor the load factor (table density) for
2318	<	* establishing the initial table size.
2318	>	* establishing the initial table size
2319		* @param concurrencyLevel the estimated number of concurrently
2320		* updating threads. The implementation may use this value as
2321		* a sizing hint.
2322		* @throws IllegalArgumentException if the initial capacity is
2323		* negative or the load factor or concurrencyLevel are
2324	<	* nonpositive.
2324	>	* nonpositive
2325		*/
2326		public ConcurrentHashMapV8(int initialCapacity,
2327		float loadFactor, int concurrencyLevel) {
#	Line 933 | Line 2330 | public class ConcurrentHashMapV8<K, V>
2330		if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2331		initialCapacity = concurrencyLevel;   // as estimated threads
2332		long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2333	<	int cap =  ((size >= (long)MAXIMUM_CAPACITY) ?
2334	<	MAXIMUM_CAPACITY: tableSizeFor((int)size));
2333	>	int cap = ((size >= (long)MAXIMUM_CAPACITY) ?
2334	>	MAXIMUM_CAPACITY: tableSizeFor((int)size));
2335		this.counter = new LongAdder();
2336	<	this.targetCapacity = cap;
2336	>	this.sizeCtl = cap;
2337		}
2338
2339		/**
#	Line 956 | Line 2353 | public class ConcurrentHashMapV8<K, V>
2353		(int)n);
2354		}
2355
2356	+	final long longSize() { // accurate version of size needed for views
2357	+	long n = counter.sum();
2358	+	return (n < 0L) ? 0L : n;
2359	+	}
2360	+
2361		/**
2362		* Returns the value to which the specified key is mapped,
2363		* or {@code null} if this map contains no mapping for the key.
#	Line 980 | Line 2382 | public class ConcurrentHashMapV8<K, V>
2382		* @param  key   possible key
2383		* @return {@code true} if and only if the specified object
2384		*         is a key in this table, as determined by the
2385	<	*         {@code equals} method; {@code false} otherwise.
2385	>	*         {@code equals} method; {@code false} otherwise
2386		* @throws NullPointerException if the specified key is null
2387		*/
2388		public boolean containsKey(Object key) {
#	Line 1003 | Line 2405 | public class ConcurrentHashMapV8<K, V>
2405		if (value == null)
2406		throw new NullPointerException();
2407		Object v;
2408	<	InternalIterator it = new InternalIterator(table);
2409	<	while (it.next != null) {
2410	<	if ((v = it.nextVal) == value || value.equals(v))
2408	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2409	>	while ((v = it.advance()) != null) {
2410	>	if (v == value || value.equals(v))
2411		return true;
1010	–	it.advance();
2412		}
2413		return false;
2414		}
#	Line 1048 | Line 2449 | public class ConcurrentHashMapV8<K, V>
2449		public V put(K key, V value) {
2450		if (key == null || value == null)
2451		throw new NullPointerException();
2452	<	return (V)internalPut(key, value, true);
2452	>	return (V)internalPut(key, value);
2453		}
2454
2455		/**
#	Line 1062 | Line 2463 | public class ConcurrentHashMapV8<K, V>
2463		public V putIfAbsent(K key, V value) {
2464		if (key == null || value == null)
2465		throw new NullPointerException();
2466	<	return (V)internalPut(key, value, false);
2466	>	return (V)internalPutIfAbsent(key, value);
2467		}
2468
2469		/**
#	Line 1073 | Line 2474 | public class ConcurrentHashMapV8<K, V>
2474		* @param m mappings to be stored in this map
2475		*/
2476		public void putAll(Map<? extends K, ? extends V> m) {
2477	<	if (m == null)
1077	<	throw new NullPointerException();
1078	<	/*
1079	<	* If uninitialized, try to adjust targetCapacity to
1080	<	* accommodate the given number of elements.
1081	<	*/
1082	<	if (table == null) {
1083	<	int size = m.size();
1084	<	int cap = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1085	<	tableSizeFor(size + (size >>> 1) + 1);
1086	<	if (cap > targetCapacity)
1087	<	targetCapacity = cap;
1088	<	}
1089	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1090	<	put(e.getKey(), e.getValue());
2477	>	internalPutAll(m);
2478		}
2479
2480		/**
2481		* If the specified key is not already associated with a value,
2482	<	* computes its value using the given mappingFunction, and if
2483	<	* non-null, enters it into the map.  This is equivalent to
2484	<	*  <pre> {@code
2482	>	* computes its value using the given mappingFunction and enters
2483	>	* it into the map unless null.  This is equivalent to
2484	>	* <pre> {@code
2485		* if (map.containsKey(key))
2486		*   return map.get(key);
2487		* value = mappingFunction.map(key);
#	Line 1102 | Line 2489 | public class ConcurrentHashMapV8<K, V>
2489		*   map.put(key, value);
2490		* return value;}</pre>
2491		*
2492	<	* except that the action is performed atomically.  Some attempted
2493	<	* update operations on this map by other threads may be blocked
2494	<	* while computation is in progress, so the computation should be
2495	<	* short and simple, and must not attempt to update any other
2496	<	* mappings of this Map. The most appropriate usage is to
2492	>	* except that the action is performed atomically.  If the
2493	>	* function returns {@code null} no mapping is recorded. If the
2494	>	* function itself throws an (unchecked) exception, the exception
2495	>	* is rethrown to its caller, and no mapping is recorded.  Some
2496	>	* attempted update operations on this map by other threads may be
2497	>	* blocked while computation is in progress, so the computation
2498	>	* should be short and simple, and must not attempt to update any
2499	>	* other mappings of this Map. The most appropriate usage is to
2500		* construct a new object serving as an initial mapped value, or
2501		* memoized result, as in:
2502	+	*
2503		*  <pre> {@code
2504		* map.computeIfAbsent(key, new MappingFunction<K, V>() {
2505		*   public V map(K k) { return new Value(f(k)); }});}</pre>
#	Line 1116 | Line 2507 | public class ConcurrentHashMapV8<K, V>
2507		* @param key key with which the specified value is to be associated
2508		* @param mappingFunction the function to compute a value
2509		* @return the current (existing or computed) value associated with
2510	<	*         the specified key, or {@code null} if the computation
1120	<	*         returned {@code null}.
2510	>	*         the specified key, or null if the computed value is null.
2511		* @throws NullPointerException if the specified key or mappingFunction
2512	<	*         is null,
2512	>	*         is null
2513		* @throws IllegalStateException if the computation detectably
2514		*         attempts a recursive update to this map that would
2515	<	*         otherwise never complete.
2515	>	*         otherwise never complete
2516		* @throws RuntimeException or Error if the mappingFunction does so,
2517	<	*         in which case the mapping is left unestablished.
2517	>	*         in which case the mapping is left unestablished
2518		*/
2519	+	@SuppressWarnings("unchecked")
2520		public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2521		if (key == null || mappingFunction == null)
2522		throw new NullPointerException();
2523	<	return internalCompute(key, mappingFunction, false);
2523	>	return (V)internalComputeIfAbsent(key, mappingFunction);
2524		}
2525
2526		/**
2527	<	* Computes the value associated with the given key using the given
2528	<	* mappingFunction, and if non-null, enters it into the map.  This
2529	<	* is equivalent to
2527	>	* Computes a new mapping value given a key and
2528	>	* its current mapped value (or {@code null} if there is no current
2529	>	* mapping). This is equivalent to
2530		*  <pre> {@code
2531	<	* value = mappingFunction.map(key);
2532	<	* if (value != null)
2533	<	*   map.put(key, value);
2534	<	* else
2535	<	*   value = map.get(key);
2536	<	* return value;}</pre>
2537	<	*
2538	<	* except that the action is performed atomically.  Some attempted
2539	<	* update operations on this map by other threads may be blocked
2540	<	* while computation is in progress, so the computation should be
2541	<	* short and simple, and must not attempt to update any other
2542	<	* mappings of this Map.
2531	>	*   value = remappingFunction.remap(key, map.get(key));
2532	>	*   if (value != null)
2533	>	*     map.put(key, value);
2534	>	*   else
2535	>	*     map.remove(key);
2536	>	* }</pre>
2537	>	*
2538	>	* except that the action is performed atomically.  If the
2539	>	* function returns {@code null}, the mapping is removed.  If the
2540	>	* function itself throws an (unchecked) exception, the exception
2541	>	* is rethrown to its caller, and the current mapping is left
2542	>	* unchanged.  Some attempted update operations on this map by
2543	>	* other threads may be blocked while computation is in progress,
2544	>	* so the computation should be short and simple, and must not
2545	>	* attempt to update any other mappings of this Map. For example,
2546	>	* to either create or append new messages to a value mapping:
2547	>	*
2548	>	* <pre> {@code
2549	>	* Map<Key, String> map = ...;
2550	>	* final String msg = ...;
2551	>	* map.compute(key, new RemappingFunction<Key, String>() {
2552	>	*   public String remap(Key k, String v) {
2553	>	*    return (v == null) ? msg : v + msg;});}}</pre>
2554		*
2555		* @param key key with which the specified value is to be associated
2556	<	* @param mappingFunction the function to compute a value
2557	<	* @return the current value associated with
2558	<	*         the specified key, or {@code null} if the computation
2559	<	*         returned {@code null} and the value was not otherwise present.
2560	<	* @throws NullPointerException if the specified key or mappingFunction
1159	<	*         is null,
2556	>	* @param remappingFunction the function to compute a value
2557	>	* @return the new value associated with
2558	>	*         the specified key, or null if none.
2559	>	* @throws NullPointerException if the specified key or remappingFunction
2560	>	*         is null
2561		* @throws IllegalStateException if the computation detectably
2562		*         attempts a recursive update to this map that would
2563	<	*         otherwise never complete.
2564	<	* @throws RuntimeException or Error if the mappingFunction does so,
2565	<	*         in which case the mapping is unchanged.
2563	>	*         otherwise never complete
2564	>	* @throws RuntimeException or Error if the remappingFunction does so,
2565	>	*         in which case the mapping is unchanged
2566		*/
2567	<	public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2568	<	if (key == null || mappingFunction == null)
2567	>	@SuppressWarnings("unchecked")
2568	>	public V compute(K key, RemappingFunction<? super K, V> remappingFunction) {
2569	>	if (key == null || remappingFunction == null)
2570		throw new NullPointerException();
2571	<	return internalCompute(key, mappingFunction, true);
2571	>	return (V)internalCompute(key, remappingFunction);
2572		}
2573
2574		/**
#	Line 1314 | Line 2716 | public class ConcurrentHashMapV8<K, V>
2716		}
2717
2718		/**
2719	+	* Returns a partionable iterator of the keys in this map.
2720	+	*
2721	+	* @return a partionable iterator of the keys in this map
2722	+	*/
2723	+	public Spliterator<K> keySpliterator() {
2724	+	return new KeyIterator<K,V>(this);
2725	+	}
2726	+
2727	+	/**
2728	+	* Returns a partionable iterator of the values in this map.
2729	+	*
2730	+	* @return a partionable iterator of the values in this map
2731	+	*/
2732	+	public Spliterator<V> valueSpliterator() {
2733	+	return new ValueIterator<K,V>(this);
2734	+	}
2735	+
2736	+	/**
2737	+	* Returns a partionable iterator of the entries in this map.
2738	+	*
2739	+	* @return a partionable iterator of the entries in this map
2740	+	*/
2741	+	public Spliterator<Map.Entry<K,V>> entrySpliterator() {
2742	+	return new EntryIterator<K,V>(this);
2743	+	}
2744	+
2745	+	/**
2746		* Returns the hash code value for this {@link Map}, i.e.,
2747		* the sum of, for each key-value pair in the map,
2748		* {@code key.hashCode() ^ value.hashCode()}.
#	Line 1322 | Line 2751 | public class ConcurrentHashMapV8<K, V>
2751		*/
2752		public int hashCode() {
2753		int h = 0;
2754	<	InternalIterator it = new InternalIterator(table);
2755	<	while (it.next != null) {
2756	<	h += it.nextKey.hashCode() ^ it.nextVal.hashCode();
2757	<	it.advance();
2754	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2755	>	Object v;
2756	>	while ((v = it.advance()) != null) {
2757	>	h += it.nextKey.hashCode() ^ v.hashCode();
2758		}
2759		return h;
2760		}
#	Line 1342 | Line 2771 | public class ConcurrentHashMapV8<K, V>
2771		* @return a string representation of this map
2772		*/
2773		public String toString() {
2774	<	InternalIterator it = new InternalIterator(table);
2774	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2775		StringBuilder sb = new StringBuilder();
2776		sb.append('{');
2777	<	if (it.next != null) {
2777	>	Object v;
2778	>	if ((v = it.advance()) != null) {
2779		for (;;) {
2780	<	Object k = it.nextKey, v = it.nextVal;
2780	>	Object k = it.nextKey;
2781		sb.append(k == this ? "(this Map)" : k);
2782		sb.append('=');
2783		sb.append(v == this ? "(this Map)" : v);
2784	<	it.advance();
1355	<	if (it.next == null)
2784	>	if ((v = it.advance()) == null)
2785		break;
2786		sb.append(',').append(' ');
2787		}
#	Line 1375 | Line 2804 | public class ConcurrentHashMapV8<K, V>
2804		if (!(o instanceof Map))
2805		return false;
2806		Map<?,?> m = (Map<?,?>) o;
2807	<	InternalIterator it = new InternalIterator(table);
2808	<	while (it.next != null) {
2809	<	Object val = it.nextVal;
2807	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2808	>	Object val;
2809	>	while ((val = it.advance()) != null) {
2810		Object v = m.get(it.nextKey);
2811		if (v == null || (v != val && !v.equals(val)))
2812		return false;
1384	–	it.advance();
2813		}
2814		for (Map.Entry<?,?> e : m.entrySet()) {
2815		Object mk, mv, v;
#	Line 1397 | Line 2825 | public class ConcurrentHashMapV8<K, V>
2825
2826		/* ----------------Iterators -------------- */
2827
2828	<	/**
2829	<	* Base class for key, value, and entry iterators.  Adds a map
2830	<	* reference to InternalIterator to support Iterator.remove.
2831	<	*/
2832	<	static abstract class ViewIterator<K,V> extends InternalIterator {
1405	<	final ConcurrentHashMapV8<K, V> map;
1406	<	ViewIterator(ConcurrentHashMapV8<K, V> map) {
1407	<	super(map.table);
1408	<	this.map = map;
2828	>	static final class KeyIterator<K,V> extends InternalIterator<K,V>
2829	>	implements Spliterator<K>, Enumeration<K> {
2830	>	KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2831	>	KeyIterator(InternalIterator<K,V> it, boolean split) {
2832	>	super(it, split);
2833		}
2834	<
2835	<	public final void remove() {
1412	<	if (last == null)
2834	>	public KeyIterator<K,V> split() {
2835	>	if (last != null || (next != null && nextVal == null))
2836		throw new IllegalStateException();
2837	<	map.remove(last.key);
2838	<	last = null;
2837	>	return new KeyIterator<K,V>(this, true);
2838	>	}
2839	>	public KeyIterator<K,V> clone() {
2840	>	if (last != null || (next != null && nextVal == null))
2841	>	throw new IllegalStateException();
2842	>	return new KeyIterator<K,V>(this, false);
2843		}
1417	–
1418	–	public final boolean hasNext()         { return next != null; }
1419	–	public final boolean hasMoreElements() { return next != null; }
1420	–	}
1421	–
1422	–	static final class KeyIterator<K,V> extends ViewIterator<K,V>
1423	–	implements Iterator<K>, Enumeration<K> {
1424	–	KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2844
2845		@SuppressWarnings("unchecked")
2846		public final K next() {
2847	<	if (next == null)
2847	>	if (nextVal == null && advance() == null)
2848		throw new NoSuchElementException();
2849		Object k = nextKey;
2850	<	advance();
2851	<	return (K)k;
2850	>	nextVal = null;
2851	>	return (K) k;
2852		}
2853
2854		public final K nextElement() { return next(); }
2855		}
2856
2857	<	static final class ValueIterator<K,V> extends ViewIterator<K,V>
2858	<	implements Iterator<V>, Enumeration<V> {
2857	>	static final class ValueIterator<K,V> extends InternalIterator<K,V>
2858	>	implements Spliterator<V>, Enumeration<V> {
2859		ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2860	+	ValueIterator(InternalIterator<K,V> it, boolean split) {
2861	+	super(it, split);
2862	+	}
2863	+	public ValueIterator<K,V> split() {
2864	+	if (last != null || (next != null && nextVal == null))
2865	+	throw new IllegalStateException();
2866	+	return new ValueIterator<K,V>(this, true);
2867	+	}
2868	+
2869	+	public ValueIterator<K,V> clone() {
2870	+	if (last != null || (next != null && nextVal == null))
2871	+	throw new IllegalStateException();
2872	+	return new ValueIterator<K,V>(this, false);
2873	+	}
2874
2875		@SuppressWarnings("unchecked")
2876		public final V next() {
2877	<	if (next == null)
2877	>	Object v;
2878	>	if ((v = nextVal) == null && (v = advance()) == null)
2879		throw new NoSuchElementException();
2880	<	Object v = nextVal;
2881	<	advance();
1448	<	return (V)v;
2880	>	nextVal = null;
2881	>	return (V) v;
2882		}
2883
2884		public final V nextElement() { return next(); }
2885		}
2886
2887	<	static final class EntryIterator<K,V> extends ViewIterator<K,V>
2888	<	implements Iterator<Map.Entry<K,V>> {
2887	>	static final class EntryIterator<K,V> extends InternalIterator<K,V>
2888	>	implements Spliterator<Map.Entry<K,V>> {
2889		EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2890	+	EntryIterator(InternalIterator<K,V> it, boolean split) {
2891	+	super(it, split);
2892	+	}
2893	+	public EntryIterator<K,V> split() {
2894	+	if (last != null || (next != null && nextVal == null))
2895	+	throw new IllegalStateException();
2896	+	return new EntryIterator<K,V>(this, true);
2897	+	}
2898	+	public EntryIterator<K,V> clone() {
2899	+	if (last != null || (next != null && nextVal == null))
2900	+	throw new IllegalStateException();
2901	+	return new EntryIterator<K,V>(this, false);
2902	+	}
2903
2904		@SuppressWarnings("unchecked")
2905		public final Map.Entry<K,V> next() {
2906	<	if (next == null)
2906	>	Object v;
2907	>	if ((v = nextVal) == null && (v = advance()) == null)
2908		throw new NoSuchElementException();
2909		Object k = nextKey;
2910	<	Object v = nextVal;
2911	<	advance();
1465	<	return new WriteThroughEntry<K,V>(map, (K)k, (V)v);
2910	>	nextVal = null;
2911	>	return new MapEntry<K,V>((K)k, (V)v, map);
2912		}
2913		}
2914
2915		/**
2916	<	* Custom Entry class used by EntryIterator.next(), that relays
1471	<	* setValue changes to the underlying map.
2916	>	* Exported Entry for iterators
2917		*/
2918	<	static final class WriteThroughEntry<K,V> implements Map.Entry<K, V> {
1474	<	final ConcurrentHashMapV8<K, V> map;
2918	>	static final class MapEntry<K,V> implements Map.Entry<K, V> {
2919		final K key; // non-null
2920		V val;       // non-null
2921	<	WriteThroughEntry(ConcurrentHashMapV8<K, V> map, K key, V val) {
2922	<	this.map = map; this.key = key; this.val = val;
2921	>	final ConcurrentHashMapV8<K, V> map;
2922	>	MapEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
2923	>	this.key = key;
2924	>	this.val = val;
2925	>	this.map = map;
2926		}
1480	–
2927		public final K getKey()       { return key; }
2928		public final V getValue()     { return val; }
2929		public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
#	Line 1494 | Line 2940 | public class ConcurrentHashMapV8<K, V>
2940
2941		/**
2942		* Sets our entry's value and writes through to the map. The
2943	<	* value to return is somewhat arbitrary here. Since a
2944	<	* WriteThroughEntry does not necessarily track asynchronous
2945	<	* changes, the most recent "previous" value could be
2946	<	* different from what we return (or could even have been
2947	<	* removed in which case the put will re-establish). We do not
1502	<	* and cannot guarantee more.
2943	>	* value to return is somewhat arbitrary here. Since a we do
2944	>	* not necessarily track asynchronous changes, the most recent
2945	>	* "previous" value could be different from what we return (or
2946	>	* could even have been removed in which case the put will
2947	>	* re-establish). We do not and cannot guarantee more.
2948		*/
2949		public final V setValue(V value) {
2950		if (value == null) throw new NullPointerException();
#	Line 1512 | Line 2957 | public class ConcurrentHashMapV8<K, V>
2957
2958		/* ----------------Views -------------- */
2959
2960	<	/*
2961	<	* These currently just extend java.util.AbstractX classes, but
1517	<	* may need a new custom base to support partitioned traversal.
2960	>	/**
2961	>	* Base class for views.
2962		*/
2963	<
1520	<	static final class KeySet<K,V> extends AbstractSet<K> {
2963	>	static abstract class MapView<K, V> {
2964		final ConcurrentHashMapV8<K, V> map;
2965	<	KeySet(ConcurrentHashMapV8<K, V> map)   { this.map = map; }
1523	<
2965	>	MapView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
2966		public final int size()                 { return map.size(); }
2967		public final boolean isEmpty()          { return map.isEmpty(); }
2968		public final void clear()               { map.clear(); }
2969	+
2970	+	// implementations below rely on concrete classes supplying these
2971	+	abstract public Iterator<?> iterator();
2972	+	abstract public boolean contains(Object o);
2973	+	abstract public boolean remove(Object o);
2974	+
2975	+	private static final String oomeMsg = "Required array size too large";
2976	+
2977	+	public final Object[] toArray() {
2978	+	long sz = map.longSize();
2979	+	if (sz > (long)(MAX_ARRAY_SIZE))
2980	+	throw new OutOfMemoryError(oomeMsg);
2981	+	int n = (int)sz;
2982	+	Object[] r = new Object[n];
2983	+	int i = 0;
2984	+	Iterator<?> it = iterator();
2985	+	while (it.hasNext()) {
2986	+	if (i == n) {
2987	+	if (n >= MAX_ARRAY_SIZE)
2988	+	throw new OutOfMemoryError(oomeMsg);
2989	+	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
2990	+	n = MAX_ARRAY_SIZE;
2991	+	else
2992	+	n += (n >>> 1) + 1;
2993	+	r = Arrays.copyOf(r, n);
2994	+	}
2995	+	r[i++] = it.next();
2996	+	}
2997	+	return (i == n) ? r : Arrays.copyOf(r, i);
2998	+	}
2999	+
3000	+	@SuppressWarnings("unchecked")
3001	+	public final <T> T[] toArray(T[] a) {
3002	+	long sz = map.longSize();
3003	+	if (sz > (long)(MAX_ARRAY_SIZE))
3004	+	throw new OutOfMemoryError(oomeMsg);
3005	+	int m = (int)sz;
3006	+	T[] r = (a.length >= m) ? a :
3007	+	(T[])java.lang.reflect.Array
3008	+	.newInstance(a.getClass().getComponentType(), m);
3009	+	int n = r.length;
3010	+	int i = 0;
3011	+	Iterator<?> it = iterator();
3012	+	while (it.hasNext()) {
3013	+	if (i == n) {
3014	+	if (n >= MAX_ARRAY_SIZE)
3015	+	throw new OutOfMemoryError(oomeMsg);
3016	+	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
3017	+	n = MAX_ARRAY_SIZE;
3018	+	else
3019	+	n += (n >>> 1) + 1;
3020	+	r = Arrays.copyOf(r, n);
3021	+	}
3022	+	r[i++] = (T)it.next();
3023	+	}
3024	+	if (a == r && i < n) {
3025	+	r[i] = null; // null-terminate
3026	+	return r;
3027	+	}
3028	+	return (i == n) ? r : Arrays.copyOf(r, i);
3029	+	}
3030	+
3031	+	public final int hashCode() {
3032	+	int h = 0;
3033	+	for (Iterator<?> it = iterator(); it.hasNext();)
3034	+	h += it.next().hashCode();
3035	+	return h;
3036	+	}
3037	+
3038	+	public final String toString() {
3039	+	StringBuilder sb = new StringBuilder();
3040	+	sb.append('[');
3041	+	Iterator<?> it = iterator();
3042	+	if (it.hasNext()) {
3043	+	for (;;) {
3044	+	Object e = it.next();
3045	+	sb.append(e == this ? "(this Collection)" : e);
3046	+	if (!it.hasNext())
3047	+	break;
3048	+	sb.append(',').append(' ');
3049	+	}
3050	+	}
3051	+	return sb.append(']').toString();
3052	+	}
3053	+
3054	+	public final boolean containsAll(Collection<?> c) {
3055	+	if (c != this) {
3056	+	for (Iterator<?> it = c.iterator(); it.hasNext();) {
3057	+	Object e = it.next();
3058	+	if (e == null || !contains(e))
3059	+	return false;
3060	+	}
3061	+	}
3062	+	return true;
3063	+	}
3064	+
3065	+	public final boolean removeAll(Collection<?> c) {
3066	+	boolean modified = false;
3067	+	for (Iterator<?> it = iterator(); it.hasNext();) {
3068	+	if (c.contains(it.next())) {
3069	+	it.remove();
3070	+	modified = true;
3071	+	}
3072	+	}
3073	+	return modified;
3074	+	}
3075	+
3076	+	public final boolean retainAll(Collection<?> c) {
3077	+	boolean modified = false;
3078	+	for (Iterator<?> it = iterator(); it.hasNext();) {
3079	+	if (!c.contains(it.next())) {
3080	+	it.remove();
3081	+	modified = true;
3082	+	}
3083	+	}
3084	+	return modified;
3085	+	}
3086	+
3087	+	}
3088	+
3089	+	static final class KeySet<K,V> extends MapView<K,V> implements Set<K> {
3090	+	KeySet(ConcurrentHashMapV8<K, V> map)   { super(map); }
3091		public final boolean contains(Object o) { return map.containsKey(o); }
3092		public final boolean remove(Object o)   { return map.remove(o) != null; }
3093		public final Iterator<K> iterator() {
3094		return new KeyIterator<K,V>(map);
3095		}
3096	+	public final boolean add(K e) {
3097	+	throw new UnsupportedOperationException();
3098	+	}
3099	+	public final boolean addAll(Collection<? extends K> c) {
3100	+	throw new UnsupportedOperationException();
3101	+	}
3102	+	public boolean equals(Object o) {
3103	+	Set<?> c;
3104	+	return ((o instanceof Set) &&
3105	+	((c = (Set<?>)o) == this ||
3106	+	(containsAll(c) && c.containsAll(this))));
3107	+	}
3108		}
3109
3110	<	static final class Values<K,V> extends AbstractCollection<V> {
3111	<	final ConcurrentHashMapV8<K, V> map;
3112	<	Values(ConcurrentHashMapV8<K, V> map)   { this.map = map; }
1537	<
1538	<	public final int size()                 { return map.size(); }
1539	<	public final boolean isEmpty()          { return map.isEmpty(); }
1540	<	public final void clear()               { map.clear(); }
3110	>	static final class Values<K,V> extends MapView<K,V>
3111	>	implements Collection<V> {
3112	>	Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
3113		public final boolean contains(Object o) { return map.containsValue(o); }
3114	+	public final boolean remove(Object o) {
3115	+	if (o != null) {
3116	+	Iterator<V> it = new ValueIterator<K,V>(map);
3117	+	while (it.hasNext()) {
3118	+	if (o.equals(it.next())) {
3119	+	it.remove();
3120	+	return true;
3121	+	}
3122	+	}
3123	+	}
3124	+	return false;
3125	+	}
3126		public final Iterator<V> iterator() {
3127		return new ValueIterator<K,V>(map);
3128		}
3129	<	}
3130	<
3131	<	static final class EntrySet<K,V> extends AbstractSet<Map.Entry<K,V>> {
3132	<	final ConcurrentHashMapV8<K, V> map;
3133	<	EntrySet(ConcurrentHashMapV8<K, V> map) { this.map = map; }
1550	<
1551	<	public final int size()                 { return map.size(); }
1552	<	public final boolean isEmpty()          { return map.isEmpty(); }
1553	<	public final void clear()               { map.clear(); }
1554	<	public final Iterator<Map.Entry<K,V>> iterator() {
1555	<	return new EntryIterator<K,V>(map);
3129	>	public final boolean add(V e) {
3130	>	throw new UnsupportedOperationException();
3131	>	}
3132	>	public final boolean addAll(Collection<? extends V> c) {
3133	>	throw new UnsupportedOperationException();
3134		}
3135	+	}
3136
3137	+	static final class EntrySet<K,V> extends MapView<K,V>
3138	+	implements Set<Map.Entry<K,V>> {
3139	+	EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
3140		public final boolean contains(Object o) {
3141		Object k, v, r; Map.Entry<?,?> e;
3142		return ((o instanceof Map.Entry) &&
#	Line 1563 | Line 3145 | public class ConcurrentHashMapV8<K, V>
3145		(v = e.getValue()) != null &&
3146		(v == r || v.equals(r)));
3147		}
1566	–
3148		public final boolean remove(Object o) {
3149		Object k, v; Map.Entry<?,?> e;
3150		return ((o instanceof Map.Entry) &&
#	Line 1571 | Line 3152 | public class ConcurrentHashMapV8<K, V>
3152		(v = e.getValue()) != null &&
3153		map.remove(k, v));
3154		}
3155	+	public final Iterator<Map.Entry<K,V>> iterator() {
3156	+	return new EntryIterator<K,V>(map);
3157	+	}
3158	+	public final boolean add(Entry<K,V> e) {
3159	+	throw new UnsupportedOperationException();
3160	+	}
3161	+	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
3162	+	throw new UnsupportedOperationException();
3163	+	}
3164	+	public boolean equals(Object o) {
3165	+	Set<?> c;
3166	+	return ((o instanceof Set) &&
3167	+	((c = (Set<?>)o) == this ||
3168	+	(containsAll(c) && c.containsAll(this))));
3169	+	}
3170		}
3171
3172		/* ---------------- Serialization Support -------------- */
#	Line 1604 | Line 3200 | public class ConcurrentHashMapV8<K, V>
3200		segments[i] = new Segment<K,V>(LOAD_FACTOR);
3201		}
3202		s.defaultWriteObject();
3203	<	InternalIterator it = new InternalIterator(table);
3204	<	while (it.next != null) {
3203	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
3204	>	Object v;
3205	>	while ((v = it.advance()) != null) {
3206		s.writeObject(it.nextKey);
3207	<	s.writeObject(it.nextVal);
1611	<	it.advance();
3207	>	s.writeObject(v);
3208		}
3209		s.writeObject(null);
3210		s.writeObject(null);
#	Line 1624 | Line 3220 | public class ConcurrentHashMapV8<K, V>
3220		throws java.io.IOException, ClassNotFoundException {
3221		s.defaultReadObject();
3222		this.segments = null; // unneeded
3223	<	// initalize transient final field
3223	>	// initialize transient final field
3224		UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
1629	–	this.targetCapacity = DEFAULT_CAPACITY;
3225
3226		// Create all nodes, then place in table once size is known
3227		long size = 0L;
#	Line 1635 | Line 3230 | public class ConcurrentHashMapV8<K, V>
3230		K k = (K) s.readObject();
3231		V v = (V) s.readObject();
3232		if (k != null && v != null) {
3233	<	p = new Node(spread(k.hashCode()), k, v, p);
3233	>	int h = spread(k.hashCode());
3234	>	p = new Node(h, k, v, p);
3235		++size;
3236		}
3237		else
#	Line 1643 | Line 3239 | public class ConcurrentHashMapV8<K, V>
3239		}
3240		if (p != null) {
3241		boolean init = false;
3242	<	if (resizing == 0 &&
3243	<	UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
3242	>	int n;
3243	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3244	>	n = MAXIMUM_CAPACITY;
3245	>	else {
3246	>	int sz = (int)size;
3247	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
3248	>	}
3249	>	int sc = sizeCtl;
3250	>	boolean collide = false;
3251	>	if (n > sc &&
3252	>	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
3253		try {
3254		if (table == null) {
3255		init = true;
1651	–	int n;
1652	–	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1653	–	n = MAXIMUM_CAPACITY;
1654	–	else {
1655	–	int sz = (int)size;
1656	–	n = tableSizeFor(sz + (sz >>> 1) + 1);
1657	–	}
1658	–	threshold = n - (n >>> 2) - THRESHOLD_OFFSET;
3256		Node[] tab = new Node[n];
3257		int mask = n - 1;
3258		while (p != null) {
3259		int j = p.hash & mask;
3260		Node next = p.next;
3261	<	p.next = tabAt(tab, j);
3261	>	Node q = p.next = tabAt(tab, j);
3262		setTabAt(tab, j, p);
3263	+	if (!collide && q != null && q.hash == p.hash)
3264	+	collide = true;
3265		p = next;
3266		}
3267		table = tab;
3268		counter.add(size);
3269	+	sc = n - (n >>> 2);
3270		}
3271		} finally {
3272	<	resizing = 0;
3272	>	sizeCtl = sc;
3273	>	}
3274	>	if (collide) { // rescan and convert to TreeBins
3275	>	Node[] tab = table;
3276	>	for (int i = 0; i < tab.length; ++i) {
3277	>	int c = 0;
3278	>	for (Node e = tabAt(tab, i); e != null; e = e.next) {
3279	>	if (++c > TREE_THRESHOLD &&
3280	>	(e.key instanceof Comparable)) {
3281	>	replaceWithTreeBin(tab, i, e.key);
3282	>	break;
3283	>	}
3284	>	}
3285	>	}
3286		}
3287		}
3288		if (!init) { // Can only happen if unsafely published.
3289		while (p != null) {
3290	<	internalPut(p.key, p.val, true);
3290	>	internalPut(p.key, p.val);
3291		p = p.next;
3292		}
3293		}
#	Line 1684 | Line 3297 | public class ConcurrentHashMapV8<K, V>
3297		// Unsafe mechanics
3298		private static final sun.misc.Unsafe UNSAFE;
3299		private static final long counterOffset;
3300	<	private static final long resizingOffset;
3300	>	private static final long sizeCtlOffset;
3301		private static final long ABASE;
3302		private static final int ASHIFT;
3303
#	Line 1695 | Line 3308 | public class ConcurrentHashMapV8<K, V>
3308		Class<?> k = ConcurrentHashMapV8.class;
3309		counterOffset = UNSAFE.objectFieldOffset
3310		(k.getDeclaredField("counter"));
3311	<	resizingOffset = UNSAFE.objectFieldOffset
3312	<	(k.getDeclaredField("resizing"));
3311	>	sizeCtlOffset = UNSAFE.objectFieldOffset
3312	>	(k.getDeclaredField("sizeCtl"));
3313		Class<?> sc = Node[].class;
3314		ABASE = UNSAFE.arrayBaseOffset(sc);
3315		ss = UNSAFE.arrayIndexScale(sc);

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