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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.1 by dl, Sun Aug 28 19:08:07 2011 UTC vs.
Revision 1.38 by dl, Wed Jun 6 15:41:23 2012 UTC

#	Line 4 | Line 4
4		* http://creativecommons.org/publicdomain/zero/1.0/
5		*/
6
7	+	// Snapshot Tue Jun  5 14:56:09 2012  Doug Lea  (dl at altair)
8	+
9		package jsr166e;
10		import jsr166e.LongAdder;
11	+	import java.util.Arrays;
12		import java.util.Map;
13		import java.util.Set;
14		import java.util.Collection;
#	Line 19 | Line 22 | import java.util.Enumeration;
22		import java.util.ConcurrentModificationException;
23		import java.util.NoSuchElementException;
24		import java.util.concurrent.ConcurrentMap;
25	+	import java.util.concurrent.ThreadLocalRandom;
26	+	import java.util.concurrent.locks.LockSupport;
27	+	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
28		import java.io.Serializable;
29
30		/**
#	Line 49 | Line 55 | import java.io.Serializable;
55		* are typically useful only when a map is not undergoing concurrent
56		* updates in other threads.  Otherwise the results of these methods
57		* reflect transient states that may be adequate for monitoring
58	<	* purposes, but not for program control.
58	>	* or estimation purposes, but not for program control.
59		*
60	<	* <p> Resizing this or any other kind of hash table is a relatively
61	<	* slow operation, so, when possible, it is a good idea to provide
62	<	* estimates of expected table sizes in constructors. Also, for
63	<	* compatability with previous versions of this class, constructors
64	<	* may optionally specify an expected {@code concurrencyLevel} as an
65	<	* additional hint for internal sizing.
60	>	* <p> The table is dynamically expanded when there are too many
61	>	* collisions (i.e., keys that have distinct hash codes but fall into
62	>	* the same slot modulo the table size), with the expected average
63	>	* effect of maintaining roughly two bins per mapping (corresponding
64	>	* to a 0.75 load factor threshold for resizing). There may be much
65	>	* variance around this average as mappings are added and removed, but
66	>	* overall, this maintains a commonly accepted time/space tradeoff for
67	>	* hash tables.  However, resizing this or any other kind of hash
68	>	* table may be a relatively slow operation. When possible, it is a
69	>	* good idea to provide a size estimate as an optional {@code
70	>	* initialCapacity} constructor argument. An additional optional
71	>	* {@code loadFactor} constructor argument provides a further means of
72	>	* customizing initial table capacity by specifying the table density
73	>	* to be used in calculating the amount of space to allocate for the
74	>	* given number of elements.  Also, for compatibility with previous
75	>	* versions of this class, constructors may optionally specify an
76	>	* expected {@code concurrencyLevel} as an additional hint for
77	>	* internal sizing.  Note that using many keys with exactly the same
78	>	* {@code hashCode()} is a sure way to slow down performance of any
79	>	* hash table.
80		*
81		* <p>This class and its views and iterators implement all of the
82		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
#	Line 82 | Line 102 | public class ConcurrentHashMapV8<K, V>
102		private static final long serialVersionUID = 7249069246763182397L;
103
104		/**
105	<	* A function computing a mapping from the given key to a value,
106	<	*  or <code>null</code> if there is no mapping. This is a
87	<	* place-holder for an upcoming JDK8 interface.
105	>	* A function computing a mapping from the given key to a value.
106	>	* This is a place-holder for an upcoming JDK8 interface.
107		*/
108		public static interface MappingFunction<K, V> {
109		/**
110	<	* Returns a value for the given key, or null if there is no
92	<	* mapping. If this function throws an (unchecked) exception,
93	<	* the exception is rethrown to its caller, and no mapping is
94	<	* recorded.  Because this function is invoked within
95	<	* atomicity control, the computation should be short and
96	<	* simple. The most common usage is to construct a new object
97	<	* serving as an initial mapped value.
110	>	* Returns a non-null value for the given key.
111		*
112		* @param key the (non-null) key
113	<	* @return a value, or null if none
113	>	* @return a non-null value
114		*/
115		V map(K key);
116		}
117
118	+	/**
119	+	* A function computing a new mapping given a key and its current
120	+	* mapped value (or {@code null} if there is no current
121	+	* mapping). This is a place-holder for an upcoming JDK8
122	+	* interface.
123	+	*/
124	+	public static interface RemappingFunction<K, V> {
125	+	/**
126	+	* Returns a new value given a key and its current value.
127	+	*
128	+	* @param key the (non-null) key
129	+	* @param value the current value, or null if there is no mapping
130	+	* @return a non-null value
131	+	*/
132	+	V remap(K key, V value);
133	+	}
134	+
135		/*
136		* Overview:
137		*
138		* The primary design goal of this hash table is to maintain
139		* concurrent readability (typically method get(), but also
140		* iterators and related methods) while minimizing update
141	<	* contention.
141	>	* contention. Secondary goals are to keep space consumption about
142	>	* the same or better than java.util.HashMap, and to support high
143	>	* initial insertion rates on an empty table by many threads.
144		*
145		* Each key-value mapping is held in a Node.  Because Node fields
146		* can contain special values, they are defined using plain Object
147		* types. Similarly in turn, all internal methods that use them
148	<	* work off Object types. All public generic-typed methods relay
149	<	* in/out of these internal methods, supplying casts as needed.
148	>	* work off Object types. And similarly, so do the internal
149	>	* methods of auxiliary iterator and view classes.  All public
150	>	* generic typed methods relay in/out of these internal methods,
151	>	* supplying null-checks and casts as needed. This also allows
152	>	* many of the public methods to be factored into a smaller number
153	>	* of internal methods (although sadly not so for the five
154	>	* variants of put-related operations). The validation-based
155	>	* approach explained below leads to a lot of code sprawl because
156	>	* retry-control precludes factoring into smaller methods.
157		*
158		* The table is lazily initialized to a power-of-two size upon the
159	<	* first insertion.  Each bin in the table contains a (typically
160	<	* short) list of Nodes.  Table accesses require volatile/atomic
161	<	* reads, writes, and CASes.  Because there is no other way to
162	<	* arrange this without adding further indirections, we use
163	<	* intrinsics (sun.misc.Unsafe) operations.  The lists of nodes
164	<	* within bins are always accurately traversable under volatile
165	<	* reads, so long as lookups check hash code and non-nullness of
166	<	* key and value before checking key equality. (All valid hash
167	<	* codes are nonnegative. Negative values are served for special
168	<	* nodes.)
169	<	*
170	<	* A bin may be locked during update (insert, delete, and replace)
171	<	* operations.  We do not want to waste the space required to
172	<	* associate a distinct lock object with each bin, so instead use
173	<	* the first node of a bin list itself as a lock, using builtin
174	<	* "synchronized" locks. These save space and we can live with
175	<	* only plain block-structured lock/unlock operations. Using the
176	<	* first node of a list as a lock does not by itself suffice
177	<	* though: When a node is locked, any update must first validate
178	<	* that it is still the first node, and retry if not. (Because new
179	<	* nodes are always appended to lists, once a node is first in a
180	<	* bin, it remains first until deleted or the bin becomes
181	<	* invalidated.)  However, update operations can and usually do
182	<	* still traverse the bin until the point of update, which helps
183	<	* reduce cache misses on retries.  This is a converse of sorts to
184	<	* the lazy locking technique described by Herlihy & Shavit. If
185	<	* there is no existing node during a put operation, then one can
186	<	* be CAS'ed in (without need for lock except in computeIfAbsent);
187	<	* the CAS serves as validation. This is on average the most
188	<	* common case for put operations. The expected number of locks
189	<	* covering different elements (i.e., bins with 2 or more nodes)
190	<	* is approximately 10% at steady state under default settings.
191	<	* Lock contention probability for two threads accessing arbitrary
192	<	* distinct elements is thus less than 1% even for small tables.
193	<	*
194	<	* The table is resized when occupancy exceeds a threshold.  Only
195	<	* a single thread performs the resize (using field "resizing", to
196	<	* arrange exclusion), but the table otherwise remains usable for
197	<	* both reads and updates. Resizing proceeds by transferring bins,
198	<	* one by one, from the table to the next table.  Upon transfer,
199	<	* the old table bin contains only a special forwarding node (with
200	<	* negative hash code ("MOVED")) that contains the next table as
159	>	* first insertion.  Each bin in the table normally contains a
160	>	* list of Nodes (most often, the list has only zero or one Node).
161	>	* Table accesses require volatile/atomic reads, writes, and
162	>	* CASes.  Because there is no other way to arrange this without
163	>	* adding further indirections, we use intrinsics
164	>	* (sun.misc.Unsafe) operations.  The lists of nodes within bins
165	>	* are always accurately traversable under volatile reads, so long
166	>	* as lookups check hash code and non-nullness of value before
167	>	* checking key equality.
168	>	*
169	>	* We use the top two bits of Node hash fields for control
170	>	* purposes -- they are available anyway because of addressing
171	>	* constraints.  As explained further below, these top bits are
172	>	* used as follows:
173	>	*  00 - Normal
174	>	*  01 - Locked
175	>	*  11 - Locked and may have a thread waiting for lock
176	>	*  10 - Node is a forwarding node
177	>	*
178	>	* The lower 30 bits of each Node's hash field contain a
179	>	* transformation of the key's hash code, except for forwarding
180	>	* nodes, for which the lower bits are zero (and so always have
181	>	* hash field == MOVED).
182	>	*
183	>	* Insertion (via put or its variants) of the first node in an
184	>	* empty bin is performed by just CASing it to the bin.  This is
185	>	* by far the most common case for put operations under most
186	>	* key/hash distributions.  Other update operations (insert,
187	>	* delete, and replace) require locks.  We do not want to waste
188	>	* the space required to associate a distinct lock object with
189	>	* each bin, so instead use the first node of a bin list itself as
190	>	* a lock. Blocking support for these locks relies on the builtin
191	>	* "synchronized" monitors.  However, we also need a tryLock
192	>	* construction, so we overlay these by using bits of the Node
193	>	* hash field for lock control (see above), and so normally use
194	>	* builtin monitors only for blocking and signalling using
195	>	* wait/notifyAll constructions. See Node.tryAwaitLock.
196	>	*
197	>	* Using the first node of a list as a lock does not by itself
198	>	* suffice though: When a node is locked, any update must first
199	>	* validate that it is still the first node after locking it, and
200	>	* retry if not. Because new nodes are always appended to lists,
201	>	* once a node is first in a bin, it remains first until deleted
202	>	* or the bin becomes invalidated (upon resizing).  However,
203	>	* operations that only conditionally update may inspect nodes
204	>	* until the point of update. This is a converse of sorts to the
205	>	* lazy locking technique described by Herlihy & Shavit.
206	>	*
207	>	* The main disadvantage of per-bin locks is that other update
208	>	* operations on other nodes in a bin list protected by the same
209	>	* lock can stall, for example when user equals() or mapping
210	>	* functions take a long time.  However, statistically, under
211	>	* random hash codes, this is not a common problem.  Ideally, the
212	>	* frequency of nodes in bins follows a Poisson distribution
213	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
214	>	* parameter of about 0.5 on average, given the resizing threshold
215	>	* of 0.75, although with a large variance because of resizing
216	>	* granularity. Ignoring variance, the expected occurrences of
217	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
218	>	* first values are:
219	>	*
220	>	* 0:    0.60653066
221	>	* 1:    0.30326533
222	>	* 2:    0.07581633
223	>	* 3:    0.01263606
224	>	* 4:    0.00157952
225	>	* 5:    0.00015795
226	>	* 6:    0.00001316
227	>	* 7:    0.00000094
228	>	* 8:    0.00000006
229	>	* more: less than 1 in ten million
230	>	*
231	>	* Lock contention probability for two threads accessing distinct
232	>	* elements is roughly 1 / (8 * #elements) under random hashes.
233	>	*
234	>	* Actual hash code distributions encountered in practice
235	>	* sometimes deviate significantly from uniform randomness.  This
236	>	* includes the case when N > (1<<30), so some keys MUST collide.
237	>	* Similarly for dumb or hostile usages in which multiple keys are
238	>	* designed to have identical hash codes. Also, although we guard
239	>	* against the worst effects of this (see method spread), sets of
240	>	* hashes may differ only in bits that do not impact their bin
241	>	* index for a given power-of-two mask.  So we use a secondary
242	>	* strategy that applies when the number of nodes in a bin exceeds
243	>	* a threshold, and at least one of the keys implements
244	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
245	>	* (a specialized form of red-black trees), bounding search time
246	>	* to O(log N).  Each search step in a TreeBin is around twice as
247	>	* slow as in a regular list, but given that N cannot exceed
248	>	* (1<<64) (before running out of addresses) this bounds search
249	>	* steps, lock hold times, etc, to reasonable constants (roughly
250	>	* 100 nodes inspected per operation worst case) so long as keys
251	>	* are Comparable (which is very common -- String, Long, etc).
252	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
253	>	* traversal pointers as regular nodes, so can be traversed in
254	>	* iterators in the same way.
255	>	*
256	>	* The table is resized when occupancy exceeds a percentage
257	>	* threshold (nominally, 0.75, but see below).  Only a single
258	>	* thread performs the resize (using field "sizeCtl", to arrange
259	>	* exclusion), but the table otherwise remains usable for reads
260	>	* and updates. Resizing proceeds by transferring bins, one by
261	>	* one, from the table to the next table.  Because we are using
262	>	* power-of-two expansion, the elements from each bin must either
263	>	* stay at same index, or move with a power of two offset. We
264	>	* eliminate unnecessary node creation by catching cases where old
265	>	* nodes can be reused because their next fields won't change.  On
266	>	* average, only about one-sixth of them need cloning when a table
267	>	* doubles. The nodes they replace will be garbage collectable as
268	>	* soon as they are no longer referenced by any reader thread that
269	>	* may be in the midst of concurrently traversing table.  Upon
270	>	* transfer, the old table bin contains only a special forwarding
271	>	* node (with hash field "MOVED") that contains the next table as
272		* its key. On encountering a forwarding node, access and update
273	<	* operations restart, using the new table. To ensure concurrent
274	<	* readability of traversals, transfers must proceed from the last
275	<	* bin (table.length - 1) up towards the first.  Any traversal
276	<	* starting from the first bin can then arrange to move to the new
277	<	* table for the rest of the traversal without revisiting nodes.
278	<	* This constrains bin transfers to a particular order, and so can
279	<	* block indefinitely waiting for the next lock, and other threads
280	<	* cannot help with the transfer. However, expected stalls are
281	<	* infrequent enough to not warrant the additional overhead and
282	<	* complexity of access and iteration schemes that could admit
283	<	* out-of-order or concurrent bin transfers.
284	<	*
285	<	* (While not yet implemented, a similar traversal scheme can
286	<	* apply to partial traversals during partitioned aggregate
287	<	* operations. Also, read-only operations give up if ever
288	<	* forwarded to a null table, which provides support for
273	>	* operations restart, using the new table.
274	>	*
275	>	* Each bin transfer requires its bin lock. However, unlike other
276	>	* cases, a transfer can skip a bin if it fails to acquire its
277	>	* lock, and revisit it later (unless it is a TreeBin). Method
278	>	* rebuild maintains a buffer of TRANSFER_BUFFER_SIZE bins that
279	>	* have been skipped because of failure to acquire a lock, and
280	>	* blocks only if none are available (i.e., only very rarely).
281	>	* The transfer operation must also ensure that all accessible
282	>	* bins in both the old and new table are usable by any traversal.
283	>	* When there are no lock acquisition failures, this is arranged
284	>	* simply by proceeding from the last bin (table.length - 1) up
285	>	* towards the first.  Upon seeing a forwarding node, traversals
286	>	* (see class InternalIterator) arrange to move to the new table
287	>	* without revisiting nodes.  However, when any node is skipped
288	>	* during a transfer, all earlier table bins may have become
289	>	* visible, so are initialized with a reverse-forwarding node back
290	>	* to the old table until the new ones are established. (This
291	>	* sometimes requires transiently locking a forwarding node, which
292	>	* is possible under the above encoding.) These more expensive
293	>	* mechanics trigger only when necessary.
294	>	*
295	>	* The traversal scheme also applies to partial traversals of
296	>	* ranges of bins (via an alternate InternalIterator constructor)
297	>	* to support partitioned aggregate operations (that are not
298	>	* otherwise implemented yet).  Also, read-only operations give up
299	>	* if ever forwarded to a null table, which provides support for
300		* shutdown-style clearing, which is also not currently
301	<	* implemented.)
301	>	* implemented.
302	>	*
303	>	* Lazy table initialization minimizes footprint until first use,
304	>	* and also avoids resizings when the first operation is from a
305	>	* putAll, constructor with map argument, or deserialization.
306	>	* These cases attempt to override the initial capacity settings,
307	>	* but harmlessly fail to take effect in cases of races.
308		*
309		* The element count is maintained using a LongAdder, which avoids
310		* contention on updates but can encounter cache thrashing if read
311	<	* too frequently during concurrent updates. To avoid reading so
312	<	* often, resizing is attempted only upon adding to a bin already
313	<	* holding two or more nodes. Under the default threshold (0.75),
314	<	* and uniform hash distributions, the probability of this
315	<	* occurring at threshold is around 13%, meaning that only about 1
316	<	* in 8 puts check threshold (and after resizing, many fewer do
317	<	* so). To increase the probablity that a resize occurs soon
318	<	* enough, we offset the threshold (see THRESHOLD_OFFSET) by the
319	<	* expected number of puts between checks. This is currently set
320	<	* to 8, in accord with the default load factor. In practice, this
321	<	* is rarely overridden, and in any case is close enough to other
322	<	* plausible values not to waste dynamic probablity computation
323	<	* for more precision.
311	>	* too frequently during concurrent access. To avoid reading so
312	>	* often, resizing is attempted either when a bin lock is
313	>	* contended, or upon adding to a bin already holding two or more
314	>	* nodes (checked before adding in the xIfAbsent methods, after
315	>	* adding in others). Under uniform hash distributions, the
316	>	* probability of this occurring at threshold is around 13%,
317	>	* meaning that only about 1 in 8 puts check threshold (and after
318	>	* resizing, many fewer do so). But this approximation has high
319	>	* variance for small table sizes, so we check on any collision
320	>	* for sizes <= 64. The bulk putAll operation further reduces
321	>	* contention by only committing count updates upon these size
322	>	* checks.
323	>	*
324	>	* Maintaining API and serialization compatibility with previous
325	>	* versions of this class introduces several oddities. Mainly: We
326	>	* leave untouched but unused constructor arguments refering to
327	>	* concurrencyLevel. We accept a loadFactor constructor argument,
328	>	* but apply it only to initial table capacity (which is the only
329	>	* time that we can guarantee to honor it.) We also declare an
330	>	* unused "Segment" class that is instantiated in minimal form
331	>	* only when serializing.
332		*/
333
334		/* ---------------- Constants -------------- */
335
336		/**
337	<	* The smallest allowed table capacity.  Must be a power of 2, at
338	<	* least 2.
337	>	* The largest possible table capacity.  This value must be
338	>	* exactly 1<<30 to stay within Java array allocation and indexing
339	>	* bounds for power of two table sizes, and is further required
340	>	* because the top two bits of 32bit hash fields are used for
341	>	* control purposes.
342		*/
343	<	static final int MINIMUM_CAPACITY = 2;
343	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
344
345		/**
346	<	* The largest allowed table capacity.  Must be a power of 2, at
347	<	* most 1<<30.
346	>	* The default initial table capacity.  Must be a power of 2
347	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
348		*/
349	<	static final int MAXIMUM_CAPACITY = 1 << 30;
349	>	private static final int DEFAULT_CAPACITY = 16;
350
351		/**
352	<	* The default initial table capacity.  Must be a power of 2, at
353	<	* least MINIMUM_CAPACITY and at most MAXIMUM_CAPACITY
352	>	* The largest possible (non-power of two) array size.
353	>	* Needed by toArray and related methods.
354		*/
355	<	static final int DEFAULT_CAPACITY = 16;
355	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
356
357		/**
358	<	* The default load factor for this table, used when not otherwise
359	<	* specified in a constructor.
358	>	* The default concurrency level for this table. Unused but
359	>	* defined for compatibility with previous versions of this class.
360		*/
361	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
361	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
362
363		/**
364	<	* The default concurrency level for this table. Unused, but
365	<	* defined for compatibility with previous versions of this class.
364	>	* The load factor for this table. Overrides of this value in
365	>	* constructors affect only the initial table capacity.  The
366	>	* actual floating point value isn't normally used -- it is
367	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
368	>	* the associated resizing threshold.
369		*/
370	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
370	>	private static final float LOAD_FACTOR = 0.75f;
371
372		/**
373	<	* The count value to offset thesholds to compensate for checking
374	<	* for resizing only when inserting into bins with two or more
375	<	* elements. See above for explanation.
373	>	* The buffer size for skipped bins during transfers. The
374	>	* value is arbitrary but should be large enough to avoid
375	>	* most locking stalls during resizes.
376		*/
377	<	static final int THRESHOLD_OFFSET = 8;
377	>	private static final int TRANSFER_BUFFER_SIZE = 32;
378
379		/**
380	<	* Special node hash value indicating to use table in node.key
381	<	* Must be negative.
380	>	* The bin count threshold for using a tree rather than list for a
381	>	* bin.  The value reflects the approximate break-even point for
382	>	* using tree-based operations.
383	>	*/
384	>	private static final int TREE_THRESHOLD = 8;
385	>
386	>	/*
387	>	* Encodings for special uses of Node hash fields. See above for
388	>	* explanation.
389		*/
390	<	static final int MOVED = -1;
390	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
391	>	static final int LOCKED    = 0x40000000; // set/tested only as a bit
392	>	static final int WAITING   = 0xc0000000; // both bits set/tested together
393	>	static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
394
395		/* ---------------- Fields -------------- */
396
397		/**
398		* The array of bins. Lazily initialized upon first insertion.
399	<	* Size is always a power of two. Accessed directly by inner
249	<	* classes.
399	>	* Size is always a power of two. Accessed directly by iterators.
400		*/
401		transient volatile Node[] table;
402
403	<	/** The counter maintaining number of elements. */
403	>	/**
404	>	* The counter maintaining number of elements.
405	>	*/
406		private transient final LongAdder counter;
407	<	/** Nonzero when table is being initialized or resized. Updated via CAS. */
408	<	private transient volatile int resizing;
409	<	/** The target load factor for the table. */
410	<	private transient float loadFactor;
411	<	/** The next element count value upon which to resize the table. */
412	<	private transient int threshold;
413	<	/** The initial capacity of the table. */
414	<	private transient int initCap;
407	>
408	>	/**
409	>	* Table initialization and resizing control.  When negative, the
410	>	* table is being initialized or resized. Otherwise, when table is
411	>	* null, holds the initial table size to use upon creation, or 0
412	>	* for default. After initialization, holds the next element count
413	>	* value upon which to resize the table.
414	>	*/
415	>	private transient volatile int sizeCtl;
416
417		// views
418	<	transient Set<K> keySet;
419	<	transient Set<Map.Entry<K,V>> entrySet;
420	<	transient Collection<V> values;
268	<
269	<	/** For serialization compatability. Null unless serialized; see below */
270	<	Segment<K,V>[] segments;
418	>	private transient KeySet<K,V> keySet;
419	>	private transient Values<K,V> values;
420	>	private transient EntrySet<K,V> entrySet;
421
422	<	/**
423	<	* Applies a supplemental hash function to a given hashCode, which
424	<	* defends against poor quality hash functions.  The result must
425	<	* be non-negative, and for reasonable performance must have good
426	<	* avalanche properties; i.e., that each bit of the argument
427	<	* affects each bit (except sign bit) of the result.
422	>	/** For serialization compatibility. Null unless serialized; see below */
423	>	private Segment<K,V>[] segments;
424	>
425	>	/* ---------------- Table element access -------------- */
426	>
427	>	/*
428	>	* Volatile access methods are used for table elements as well as
429	>	* elements of in-progress next table while resizing.  Uses are
430	>	* null checked by callers, and implicitly bounds-checked, relying
431	>	* on the invariants that tab arrays have non-zero size, and all
432	>	* indices are masked with (tab.length - 1) which is never
433	>	* negative and always less than length. Note that, to be correct
434	>	* wrt arbitrary concurrency errors by users, bounds checks must
435	>	* operate on local variables, which accounts for some odd-looking
436	>	* inline assignments below.
437		*/
438	<	private static final int spread(int h) {
439	<	// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
440	<	h ^= h >>> 16;
441	<	h *= 0x85ebca6b;
442	<	h ^= h >>> 13;
443	<	h *= 0xc2b2ae35;
444	<	return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit
438	>
439	>	static final Node tabAt(Node[] tab, int i) { // used by InternalIterator
440	>	return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
441	>	}
442	>
443	>	private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) {
444	>	return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v);
445		}
446
447	+	private static final void setTabAt(Node[] tab, int i, Node v) {
448	+	UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
449	+	}
450	+
451	+	/* ---------------- Nodes -------------- */
452	+
453		/**
454		* Key-value entry. Note that this is never exported out as a
455	<	* user-visible Map.Entry.
455	>	* user-visible Map.Entry (see WriteThroughEntry and SnapshotEntry
456	>	* below). Nodes with a hash field of MOVED are special, and do
457	>	* not contain user keys or values.  Otherwise, keys are never
458	>	* null, and null val fields indicate that a node is in the
459	>	* process of being deleted or created. For purposes of read-only
460	>	* access, a key may be read before a val, but can only be used
461	>	* after checking val to be non-null.
462		*/
463	<	static final class Node {
464	<	final int hash;
463	>	static class Node {
464	>	volatile int hash;
465		final Object key;
466		volatile Object val;
467		volatile Node next;
#	Line 301 | Line 472 | public class ConcurrentHashMapV8<K, V>
472		this.val = val;
473		this.next = next;
474		}
304	–	}
475
476	<	/*
477	<	* Volatile access nethods are used for table elements as well as
478	<	* elements of in-progress next table while resizing.  Uses in
479	<	* access and update methods are null checked by callers, and
310	<	* implicitly bounds-checked, relying on the invariants that tab
311	<	* arrays have non-zero size, and all indices are masked with
312	<	* (tab.length - 1) which is never negative and always less than
313	<	* length. The only other usage is in HashIterator.advance, which
314	<	* performs explicit checks.
315	<	*/
476	>	/** CompareAndSet the hash field */
477	>	final boolean casHash(int cmp, int val) {
478	>	return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
479	>	}
480
481	<	static final Node tabAt(Node[] tab, int i) { // used in HashIterator
482	<	return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
483	<	}
481	>	/** The number of spins before blocking for a lock */
482	>	static final int MAX_SPINS =
483	>	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
484
485	<	private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) {
486	<	return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v);
485	>	/**
486	>	* Spins a while if LOCKED bit set and this node is the first
487	>	* of its bin, and then sets WAITING bits on hash field and
488	>	* blocks (once) if they are still set.  It is OK for this
489	>	* method to return even if lock is not available upon exit,
490	>	* which enables these simple single-wait mechanics.
491	>	*
492	>	* The corresponding signalling operation is performed within
493	>	* callers: Upon detecting that WAITING has been set when
494	>	* unlocking lock (via a failed CAS from non-waiting LOCKED
495	>	* state), unlockers acquire the sync lock and perform a
496	>	* notifyAll.
497	>	*/
498	>	final void tryAwaitLock(Node[] tab, int i) {
499	>	if (tab != null && i >= 0 && i < tab.length) { // bounds check
500	>	int r = ThreadLocalRandom.current().nextInt(); // randomize spins
501	>	int spins = MAX_SPINS, h;
502	>	while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
503	>	if (spins >= 0) {
504	>	r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
505	>	if (r >= 0 && --spins == 0)
506	>	Thread.yield();  // yield before block
507	>	}
508	>	else if (casHash(h, h | WAITING)) {
509	>	synchronized (this) {
510	>	if (tabAt(tab, i) == this &&
511	>	(hash & WAITING) == WAITING) {
512	>	try {
513	>	wait();
514	>	} catch (InterruptedException ie) {
515	>	Thread.currentThread().interrupt();
516	>	}
517	>	}
518	>	else
519	>	notifyAll(); // possibly won race vs signaller
520	>	}
521	>	break;
522	>	}
523	>	}
524	>	}
525	>	}
526	>
527	>	// Unsafe mechanics for casHash
528	>	private static final sun.misc.Unsafe UNSAFE;
529	>	private static final long hashOffset;
530	>
531	>	static {
532	>	try {
533	>	UNSAFE = getUnsafe();
534	>	Class<?> k = Node.class;
535	>	hashOffset = UNSAFE.objectFieldOffset
536	>	(k.getDeclaredField("hash"));
537	>	} catch (Exception e) {
538	>	throw new Error(e);
539	>	}
540	>	}
541		}
542
543	<	private static final void setTabAt(Node[] tab, int i, Node v) {
544	<	UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
543	>	/* ---------------- TreeBins -------------- */
544	>
545	>	/**
546	>	* Nodes for use in TreeBins
547	>	*/
548	>	static final class TreeNode extends Node {
549	>	TreeNode parent;  // red-black tree links
550	>	TreeNode left;
551	>	TreeNode right;
552	>	TreeNode prev;    // needed to unlink next upon deletion
553	>	boolean red;
554	>
555	>	TreeNode(int hash, Object key, Object val, Node next, TreeNode parent) {
556	>	super(hash, key, val, next);
557	>	this.parent = parent;
558	>	}
559		}
560
561	<	/* ---------------- Access and update operations -------------- */
561	>	/**
562	>	* A specialized form of red-black tree for use in bins
563	>	* whose size exceeds a threshold.
564	>	*
565	>	* TreeBins use a special form of comparison for search and
566	>	* related operations (which is the main reason we cannot use
567	>	* existing collections such as TreeMaps). TreeBins contain
568	>	* Comparable elements, but may contain others, as well as
569	>	* elements that are Comparable but not necessarily Comparable<T>
570	>	* for the same T, so we cannot invoke compareTo among them. To
571	>	* handle this, the tree is ordered primarily by hash value, then
572	>	* by getClass().getName() order, and then by Comparator order
573	>	* among elements of the same class.  On lookup at a node, if
574	>	* non-Comparable, both left and right children may need to be
575	>	* searched in the case of tied hash values. (This corresponds to
576	>	* the full list search that would be necessary if all elements
577	>	* were non-Comparable and had tied hashes.)
578	>	*
579	>	* TreeBins also maintain a separate locking discipline than
580	>	* regular bins. Because they are forwarded via special MOVED
581	>	* nodes at bin heads (which can never change once established),
582	>	* we cannot use use those nodes as locks. Instead, TreeBin
583	>	* extends AbstractQueuedSynchronizer to support a simple form of
584	>	* read-write lock. For update operations and table validation,
585	>	* the exclusive form of lock behaves in the same way as bin-head
586	>	* locks. However, lookups use shared read-lock mechanics to allow
587	>	* multiple readers in the absence of writers.  Additionally,
588	>	* these lookups do not ever block: While the lock is not
589	>	* available, they proceed along the slow traversal path (via
590	>	* next-pointers) until the lock becomes available or the list is
591	>	* exhausted, whichever comes first. (These cases are not fast,
592	>	* but maximize aggregate expected throughput.)  The AQS mechanics
593	>	* for doing this are straightforward.  The lock state is held as
594	>	* AQS getState().  Read counts are negative; the write count (1)
595	>	* is positive.  There are no signalling preferences among readers
596	>	* and writers. Since we don't need to export full Lock API, we
597	>	* just override the minimal AQS methods and use them directly.
598	>	*/
599	>	static final class TreeBin extends AbstractQueuedSynchronizer {
600	>	private static final long serialVersionUID = 2249069246763182397L;
601	>	TreeNode root;  // root of tree
602	>	TreeNode first; // head of next-pointer list
603
604	<	/** Implements get and containsKey **/
605	<	private final Object internalGet(Object k) {
606	<	int h = spread(k.hashCode());
607	<	Node[] tab = table;
608	<	retry: while (tab != null) {
609	<	Node e = tabAt(tab, (tab.length - 1) & h);
337	<	while (e != null) {
338	<	int eh = e.hash;
339	<	if (eh == h) {
340	<	Object ek = e.key, ev = e.val;
341	<	if (ev != null && ek != null && (k == ek || k.equals(ek)))
342	<	return ev;
343	<	}
344	<	if (eh < 0) { // bin was moved during resize
345	<	tab = (Node[])e.key;
346	<	continue retry;
347	<	}
348	<	e = e.next;
604	>	/* AQS overrides */
605	>	public final boolean isHeldExclusively() { return getState() > 0; }
606	>	public final boolean tryAcquire(int ignore) {
607	>	if (compareAndSetState(0, 1)) {
608	>	setExclusiveOwnerThread(Thread.currentThread());
609	>	return true;
610		}
611	<	break;
611	>	return false;
612	>	}
613	>	public final boolean tryRelease(int ignore) {
614	>	setExclusiveOwnerThread(null);
615	>	setState(0);
616	>	return true;
617	>	}
618	>	public final int tryAcquireShared(int ignore) {
619	>	for (int c;;) {
620	>	if ((c = getState()) > 0)
621	>	return -1;
622	>	if (compareAndSetState(c, c -1))
623	>	return 1;
624	>	}
625	>	}
626	>	public final boolean tryReleaseShared(int ignore) {
627	>	int c;
628	>	do {} while (!compareAndSetState(c = getState(), c + 1));
629	>	return c == -1;
630		}
352	–	return null;
353	–	}
631
632	<	/** Implements put and putIfAbsent **/
633	<	private final Object internalPut(Object k, Object v, boolean replace) {
634	<	int h = spread(k.hashCode());
635	<	Object oldVal = null;  // the previous value or null if none
636	<	Node node = null;      // the node created if absent
637	<	Node[] tab = table;
638	<	for (;;) {
639	<	Node e; int i;
640	<	if (tab == null)
641	<	tab = grow(0);
642	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
643	<	if (node == null)
644	<	node = new Node(h, k, v, null);
645	<	if (casTabAt(tab, i, null, node))
632	>	/**
633	>	* Return the TreeNode (or null if not found) for the given key
634	>	* starting at given root.
635	>	*/
636	>	@SuppressWarnings("unchecked") // suppress Comparable cast warning
637	>	final TreeNode getTreeNode(int h, Object k, TreeNode p) {
638	>	Class<?> c = k.getClass();
639	>	while (p != null) {
640	>	int dir, ph;  Object pk; Class<?> pc; TreeNode r;
641	>	if (h < (ph = p.hash))
642	>	dir = -1;
643	>	else if (h > ph)
644	>	dir = 1;
645	>	else if ((pk = p.key) == k || k.equals(pk))
646	>	return p;
647	>	else if (c != (pc = pk.getClass()))
648	>	dir = c.getName().compareTo(pc.getName());
649	>	else if (k instanceof Comparable)
650	>	dir = ((Comparable)k).compareTo((Comparable)pk);
651	>	else
652	>	dir = 0;
653	>	TreeNode pr = p.right;
654	>	if (dir > 0)
655	>	p = pr;
656	>	else if (dir == 0 && pr != null && h >= pr.hash &&
657	>	(r = getTreeNode(h, k, pr)) != null)
658	>	return r;
659	>	else
660	>	p = p.left;
661	>	}
662	>	return null;
663	>	}
664	>
665	>	/**
666	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
667	>	* read-lock to call getTreeNode, but during failure to get
668	>	* lock, searches along next links.
669	>	*/
670	>	final Object getValue(int h, Object k) {
671	>	Node r = null;
672	>	int c = getState(); // Must read lock state first
673	>	for (Node e = first; e != null; e = e.next) {
674	>	if (c <= 0 && compareAndSetState(c, c - 1)) {
675	>	try {
676	>	r = getTreeNode(h, k, root);
677	>	} finally {
678	>	releaseShared(0);
679	>	}
680		break;
681	+	}
682	+	else if ((e.hash & HASH_BITS) == h && k.equals(e.key)) {
683	+	r = e;
684	+	break;
685	+	}
686	+	else
687	+	c = getState();
688		}
689	<	else if (e.hash < 0)
690	<	tab = (Node[])e.key;
691	<	else {
692	<	boolean validated = false;
693	<	boolean checkSize = false;
694	<	synchronized(e) {
695	<	Node first = e;
696	<	for (;;) {
697	<	Object ek, ev;
698	<	if ((ev = e.val) == null)
689	>	return r == null ? null : r.val;
690	>	}
691	>
692	>	/**
693	>	* Find or add a node
694	>	* @return null if added
695	>	*/
696	>	@SuppressWarnings("unchecked") // suppress Comparable cast warning
697	>	final TreeNode putTreeNode(int h, Object k, Object v) {
698	>	Class<?> c = k.getClass();
699	>	TreeNode p = root;
700	>	int dir = 0;
701	>	if (p != null) {
702	>	for (;;) {
703	>	int ph;  Object pk; Class<?> pc; TreeNode r;
704	>	if (h < (ph = p.hash))
705	>	dir = -1;
706	>	else if (h > ph)
707	>	dir = 1;
708	>	else if ((pk = p.key) == k || k.equals(pk))
709	>	return p;
710	>	else if (c != (pc = (pk = p.key).getClass()))
711	>	dir = c.getName().compareTo(pc.getName());
712	>	else if (k instanceof Comparable)
713	>	dir = ((Comparable)k).compareTo((Comparable)pk);
714	>	else
715	>	dir = 0;
716	>	TreeNode pr = p.right, pl;
717	>	if (dir > 0) {
718	>	if (pr == null)
719		break;
720	<	if (e.hash == h && (ek = e.key) != null &&
721	<	(k == ek || k.equals(ek))) {
722	<	if (tabAt(tab, i) == first) {
723	<	validated = true;
724	<	oldVal = ev;
725	<	if (replace)
726	<	e.val = v;
720	>	p = pr;
721	>	}
722	>	else if (dir == 0 && pr != null && h >= pr.hash &&
723	>	(r = getTreeNode(h, k, pr)) != null)
724	>	return r;
725	>	else if ((pl = p.left) == null)
726	>	break;
727	>	else
728	>	p = pl;
729	>	}
730	>	}
731	>	TreeNode f = first;
732	>	TreeNode r = first = new TreeNode(h, k, v, f, p);
733	>	if (p == null)
734	>	root = r;
735	>	else {
736	>	if (dir <= 0)
737	>	p.left = r;
738	>	else
739	>	p.right = r;
740	>	if (f != null)
741	>	f.prev = r;
742	>	fixAfterInsertion(r);
743	>	}
744	>	return null;
745	>	}
746	>
747	>	/**
748	>	* Removes the given node, that must be present before this
749	>	* call.  This is messier than typical red-black deletion code
750	>	* because we cannot swap the contents of an interior node
751	>	* with a leaf successor that is pinned by "next" pointers
752	>	* that are accessible independently of lock. So instead we
753	>	* swap the tree linkages.
754	>	*/
755	>	final void deleteTreeNode(TreeNode p) {
756	>	TreeNode next = (TreeNode)p.next; // unlink traversal pointers
757	>	TreeNode pred = p.prev;
758	>	if (pred == null)
759	>	first = next;
760	>	else
761	>	pred.next = next;
762	>	if (next != null)
763	>	next.prev = pred;
764	>	TreeNode replacement;
765	>	TreeNode pl = p.left;
766	>	TreeNode pr = p.right;
767	>	if (pl != null && pr != null) {
768	>	TreeNode s = pr;
769	>	while (s.left != null) // find successor
770	>	s = s.left;
771	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
772	>	TreeNode sr = s.right;
773	>	TreeNode pp = p.parent;
774	>	if (s == pr) { // p was s's direct parent
775	>	p.parent = s;
776	>	s.right = p;
777	>	}
778	>	else {
779	>	TreeNode sp = s.parent;
780	>	if ((p.parent = sp) != null) {
781	>	if (s == sp.left)
782	>	sp.left = p;
783	>	else
784	>	sp.right = p;
785	>	}
786	>	if ((s.right = pr) != null)
787	>	pr.parent = s;
788	>	}
789	>	p.left = null;
790	>	if ((p.right = sr) != null)
791	>	sr.parent = p;
792	>	if ((s.left = pl) != null)
793	>	pl.parent = s;
794	>	if ((s.parent = pp) == null)
795	>	root = s;
796	>	else if (p == pp.left)
797	>	pp.left = s;
798	>	else
799	>	pp.right = s;
800	>	replacement = sr;
801	>	}
802	>	else
803	>	replacement = (pl != null) ? pl : pr;
804	>	TreeNode pp = p.parent;
805	>	if (replacement == null) {
806	>	if (pp == null) {
807	>	root = null;
808	>	return;
809	>	}
810	>	replacement = p;
811	>	}
812	>	else {
813	>	replacement.parent = pp;
814	>	if (pp == null)
815	>	root = replacement;
816	>	else if (p == pp.left)
817	>	pp.left = replacement;
818	>	else
819	>	pp.right = replacement;
820	>	p.left = p.right = p.parent = null;
821	>	}
822	>	if (!p.red)
823	>	fixAfterDeletion(replacement);
824	>	if (p == replacement && (pp = p.parent) != null) {
825	>	if (p == pp.left) // detach pointers
826	>	pp.left = null;
827	>	else if (p == pp.right)
828	>	pp.right = null;
829	>	p.parent = null;
830	>	}
831	>	}
832	>
833	>	// CLR code updated from pre-jdk-collections version at
834	>	// http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java
835	>
836	>	/** From CLR */
837	>	private void rotateLeft(TreeNode p) {
838	>	if (p != null) {
839	>	TreeNode r = p.right, pp, rl;
840	>	if ((rl = p.right = r.left) != null)
841	>	rl.parent = p;
842	>	if ((pp = r.parent = p.parent) == null)
843	>	root = r;
844	>	else if (pp.left == p)
845	>	pp.left = r;
846	>	else
847	>	pp.right = r;
848	>	r.left = p;
849	>	p.parent = r;
850	>	}
851	>	}
852	>
853	>	/** From CLR */
854	>	private void rotateRight(TreeNode p) {
855	>	if (p != null) {
856	>	TreeNode l = p.left, pp, lr;
857	>	if ((lr = p.left = l.right) != null)
858	>	lr.parent = p;
859	>	if ((pp = l.parent = p.parent) == null)
860	>	root = l;
861	>	else if (pp.right == p)
862	>	pp.right = l;
863	>	else
864	>	pp.left = l;
865	>	l.right = p;
866	>	p.parent = l;
867	>	}
868	>	}
869	>
870	>	/** From CLR */
871	>	private void fixAfterInsertion(TreeNode x) {
872	>	x.red = true;
873	>	TreeNode xp, xpp;
874	>	while (x != null && (xp = x.parent) != null && xp.red &&
875	>	(xpp = xp.parent) != null) {
876	>	TreeNode xppl = xpp.left;
877	>	if (xp == xppl) {
878	>	TreeNode y = xpp.right;
879	>	if (y != null && y.red) {
880	>	y.red = false;
881	>	xp.red = false;
882	>	xpp.red = true;
883	>	x = xpp;
884	>	}
885	>	else {
886	>	if (x == xp.right) {
887	>	x = xp;
888	>	rotateLeft(x);
889	>	xpp = (xp = x.parent) == null ? null : xp.parent;
890	>	}
891	>	if (xp != null) {
892	>	xp.red = false;
893	>	if (xpp != null) {
894	>	xpp.red = true;
895	>	rotateRight(xpp);
896		}
390	–	break;
897		}
898	<	Node last = e;
899	<	if ((e = e.next) == null) {
900	<	if (tabAt(tab, i) == first) {
901	<	validated = true;
902	<	if (node == null)
903	<	node = new Node(h, k, v, null);
904	<	last.next = node;
905	<	if (last != first)
906	<	checkSize = true;
898	>	}
899	>	}
900	>	else {
901	>	TreeNode y = xppl;
902	>	if (y != null && y.red) {
903	>	y.red = false;
904	>	xp.red = false;
905	>	xpp.red = true;
906	>	x = xpp;
907	>	}
908	>	else {
909	>	if (x == xp.left) {
910	>	x = xp;
911	>	rotateRight(x);
912	>	xpp = (xp = x.parent) == null ? null : xp.parent;
913	>	}
914	>	if (xp != null) {
915	>	xp.red = false;
916	>	if (xpp != null) {
917	>	xpp.red = true;
918	>	rotateLeft(xpp);
919		}
402	–	break;
920		}
921		}
922		}
923	<	if (validated) {
924	<	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
925	<	resizing == 0 && counter.sum() >= threshold)
926	<	grow(0);
923	>	}
924	>	TreeNode r = root;
925	>	if (r != null && r.red)
926	>	r.red = false;
927	>	}
928	>
929	>	/** From CLR */
930	>	private void fixAfterDeletion(TreeNode x) {
931	>	while (x != null) {
932	>	TreeNode xp, xpl;
933	>	if (x.red || (xp = x.parent) == null) {
934	>	x.red = false;
935		break;
936		}
937	+	if (x == (xpl = xp.left)) {
938	+	TreeNode sib = xp.right;
939	+	if (sib != null && sib.red) {
940	+	sib.red = false;
941	+	xp.red = true;
942	+	rotateLeft(xp);
943	+	sib = (xp = x.parent) == null ? null : xp.right;
944	+	}
945	+	if (sib == null)
946	+	x = xp;
947	+	else {
948	+	TreeNode sl = sib.left, sr = sib.right;
949	+	if ((sr == null || !sr.red) &&
950	+	(sl == null || !sl.red)) {
951	+	sib.red = true;
952	+	x = xp;
953	+	}
954	+	else {
955	+	if (sr == null || !sr.red) {
956	+	if (sl != null)
957	+	sl.red = false;
958	+	sib.red = true;
959	+	rotateRight(sib);
960	+	sib = (xp = x.parent) == null ? null : xp.right;
961	+	}
962	+	if (sib != null) {
963	+	sib.red = (xp == null)? false : xp.red;
964	+	if ((sr = sib.right) != null)
965	+	sr.red = false;
966	+	}
967	+	if (xp != null) {
968	+	xp.red = false;
969	+	rotateLeft(xp);
970	+	}
971	+	x = root;
972	+	}
973	+	}
974	+	}
975	+	else { // symmetric
976	+	TreeNode sib = xpl;
977	+	if (sib != null && sib.red) {
978	+	sib.red = false;
979	+	xp.red = true;
980	+	rotateRight(xp);
981	+	sib = (xp = x.parent) == null ? null : xp.left;
982	+	}
983	+	if (sib == null)
984	+	x = xp;
985	+	else {
986	+	TreeNode sl = sib.left, sr = sib.right;
987	+	if ((sl == null || !sl.red) &&
988	+	(sr == null || !sr.red)) {
989	+	sib.red = true;
990	+	x = xp;
991	+	}
992	+	else {
993	+	if (sl == null || !sl.red) {
994	+	if (sr != null)
995	+	sr.red = false;
996	+	sib.red = true;
997	+	rotateLeft(sib);
998	+	sib = (xp = x.parent) == null ? null : xp.left;
999	+	}
1000	+	if (sib != null) {
1001	+	sib.red = (xp == null)? false : xp.red;
1002	+	if ((sl = sib.left) != null)
1003	+	sl.red = false;
1004	+	}
1005	+	if (xp != null) {
1006	+	xp.red = false;
1007	+	rotateRight(xp);
1008	+	}
1009	+	x = root;
1010	+	}
1011	+	}
1012	+	}
1013		}
1014		}
1015	<	if (oldVal == null)
1016	<	counter.increment();
1017	<	return oldVal;
1015	>	}
1016	>
1017	>	/* ---------------- Collision reduction methods -------------- */
1018	>
1019	>	/**
1020	>	* Spreads higher bits to lower, and also forces top 2 bits to 0.
1021	>	* Because the table uses power-of-two masking, sets of hashes
1022	>	* that vary only in bits above the current mask will always
1023	>	* collide. (Among known examples are sets of Float keys holding
1024	>	* consecutive whole numbers in small tables.)  To counter this,
1025	>	* we apply a transform that spreads the impact of higher bits
1026	>	* downward. There is a tradeoff between speed, utility, and
1027	>	* quality of bit-spreading. Because many common sets of hashes
1028	>	* are already reaonably distributed across bits (so don't benefit
1029	>	* from spreading), and because we use trees to handle large sets
1030	>	* of collisions in bins, we don't need excessively high quality.
1031	>	*/
1032	>	private static final int spread(int h) {
1033	>	h ^= (h >>> 18) ^ (h >>> 12);
1034	>	return (h ^ (h >>> 10)) & HASH_BITS;
1035		}
1036
1037		/**
1038	<	* Covers the four public remove/replace methods: Replaces node
1039	<	* value with v, conditional upon match of cv if non-null.  If
1040	<	* resulting value is null, delete.
1038	>	* Replaces a list bin with a tree bin. Call only when locked.
1039	>	* Fails to replace if the given key is non-comparable or table
1040	>	* is, or needs, resizing.
1041	>	*/
1042	>	private final void replaceWithTreeBin(Node[] tab, int index, Object key) {
1043	>	if ((key instanceof Comparable) &&
1044	>	(tab.length >= MAXIMUM_CAPACITY || counter.sum() < (long)sizeCtl)) {
1045	>	TreeBin t = new TreeBin();
1046	>	for (Node e = tabAt(tab, index); e != null; e = e.next)
1047	>	t.putTreeNode(e.hash & HASH_BITS, e.key, e.val);
1048	>	setTabAt(tab, index, new Node(MOVED, t, null, null));
1049	>	}
1050	>	}
1051	>
1052	>	/* ---------------- Internal access and update methods -------------- */
1053	>
1054	>	/** Implementation for get and containsKey */
1055	>	private final Object internalGet(Object k) {
1056	>	int h = spread(k.hashCode());
1057	>	retry: for (Node[] tab = table; tab != null;) {
1058	>	Node e, p; Object ek, ev; int eh;      // locals to read fields once
1059	>	for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1060	>	if ((eh = e.hash) == MOVED) {
1061	>	if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1062	>	return ((TreeBin)ek).getValue(h, k);
1063	>	else {                        // restart with new table
1064	>	tab = (Node[])ek;
1065	>	continue retry;
1066	>	}
1067	>	}
1068	>	else if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
1069	>	((ek = e.key) == k || k.equals(ek)))
1070	>	return ev;
1071	>	}
1072	>	break;
1073	>	}
1074	>	return null;
1075	>	}
1076	>
1077	>	/**
1078	>	* Implementation for the four public remove/replace methods:
1079	>	* Replaces node value with v, conditional upon match of cv if
1080	>	* non-null.  If resulting value is null, delete.
1081		*/
1082		private final Object internalReplace(Object k, Object v, Object cv) {
1083		int h = spread(k.hashCode());
1084		Object oldVal = null;
1085	<	Node e; int i;
1086	<	Node[] tab = table;
1087	<	while (tab != null &&
1088	<	(e = tabAt(tab, i = (tab.length - 1) & h)) != null) {
1089	<	if (e.hash < 0)
1090	<	tab = (Node[])e.key;
1091	<	else {
1085	>	for (Node[] tab = table;;) {
1086	>	Node f; int i, fh; Object fk;
1087	>	if (tab == null ||
1088	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1089	>	break;
1090	>	else if ((fh = f.hash) == MOVED) {
1091	>	if ((fk = f.key) instanceof TreeBin) {
1092	>	TreeBin t = (TreeBin)fk;
1093	>	boolean validated = false;
1094	>	boolean deleted = false;
1095	>	t.acquire(0);
1096	>	try {
1097	>	if (tabAt(tab, i) == f) {
1098	>	validated = true;
1099	>	TreeNode p = t.getTreeNode(h, k, t.root);
1100	>	if (p != null) {
1101	>	Object pv = p.val;
1102	>	if (cv == null || cv == pv || cv.equals(pv)) {
1103	>	oldVal = pv;
1104	>	if ((p.val = v) == null) {
1105	>	deleted = true;
1106	>	t.deleteTreeNode(p);
1107	>	}
1108	>	}
1109	>	}
1110	>	}
1111	>	} finally {
1112	>	t.release(0);
1113	>	}
1114	>	if (validated) {
1115	>	if (deleted)
1116	>	counter.add(-1L);
1117	>	break;
1118	>	}
1119	>	}
1120	>	else
1121	>	tab = (Node[])fk;
1122	>	}
1123	>	else if ((fh & HASH_BITS) != h && f.next == null) // precheck
1124	>	break;                          // rules out possible existence
1125	>	else if ((fh & LOCKED) != 0) {
1126	>	checkForResize();               // try resizing if can't get lock
1127	>	f.tryAwaitLock(tab, i);
1128	>	}
1129	>	else if (f.casHash(fh, fh | LOCKED)) {
1130		boolean validated = false;
1131		boolean deleted = false;
1132	<	synchronized(e) {
1133	<	Node pred = null;
1134	<	Node first = e;
1135	<	for (;;) {
1136	<	Object ek, ev;
1137	<	if ((ev = e.val) == null)
1138	<	break;
1139	<	if (e.hash == h && (ek = e.key) != null &&
444	<	(k == ek || k.equals(ek))) {
445	<	if (tabAt(tab, i) == first) {
446	<	validated = true;
1132	>	try {
1133	>	if (tabAt(tab, i) == f) {
1134	>	validated = true;
1135	>	for (Node e = f, pred = null;;) {
1136	>	Object ek, ev;
1137	>	if ((e.hash & HASH_BITS) == h &&
1138	>	((ev = e.val) != null) &&
1139	>	((ek = e.key) == k || k.equals(ek))) {
1140		if (cv == null || cv == ev || cv.equals(ev)) {
1141		oldVal = ev;
1142		if ((e.val = v) == null) {
#	Line 455 | Line 1148 | public class ConcurrentHashMapV8<K, V>
1148		setTabAt(tab, i, en);
1149		}
1150		}
1151	+	break;
1152		}
1153	<	break;
1154	<	}
1155	<	pred = e;
462	<	if ((e = e.next) == null) {
463	<	if (tabAt(tab, i) == first)
464	<	validated = true;
465	<	break;
1153	>	pred = e;
1154	>	if ((e = e.next) == null)
1155	>	break;
1156		}
1157		}
1158	+	} finally {
1159	+	if (!f.casHash(fh | LOCKED, fh)) {
1160	+	f.hash = fh;
1161	+	synchronized (f) { f.notifyAll(); };
1162	+	}
1163		}
1164		if (validated) {
1165		if (deleted)
1166	<	counter.decrement();
1166	>	counter.add(-1L);
1167		break;
1168		}
1169		}
#	Line 476 | Line 1171 | public class ConcurrentHashMapV8<K, V>
1171		return oldVal;
1172		}
1173
1174	<	/** Implements computeIfAbsent */
1175	<	@SuppressWarnings("unchecked")
1176	<	private final V computeVal(K k, MappingFunction<? super K, ? extends V> f) {
1174	>	/*
1175	>	* Internal versions of the five insertion methods, each a
1176	>	* little more complicated than the last. All have
1177	>	* the same basic structure as the first (internalPut):
1178	>	*  1. If table uninitialized, create
1179	>	*  2. If bin empty, try to CAS new node
1180	>	*  3. If bin stale, use new table
1181	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1182	>	*  5. Lock and validate; if valid, scan and add or update
1183	>	*
1184	>	* The others interweave other checks and/or alternative actions:
1185	>	*  * Plain put checks for and performs resize after insertion.
1186	>	*  * putIfAbsent prescans for mapping without lock (and fails to add
1187	>	*    if present), which also makes pre-emptive resize checks worthwhile.
1188	>	*  * computeIfAbsent extends form used in putIfAbsent with additional
1189	>	*    mechanics to deal with, calls, potential exceptions and null
1190	>	*    returns from function call.
1191	>	*  * compute uses the same function-call mechanics, but without
1192	>	*    the prescans
1193	>	*  * putAll attempts to pre-allocate enough table space
1194	>	*    and more lazily performs count updates and checks.
1195	>	*
1196	>	* Someday when details settle down a bit more, it might be worth
1197	>	* some factoring to reduce sprawl.
1198	>	*/
1199	>
1200	>	/** Implementation for put */
1201	>	private final Object internalPut(Object k, Object v) {
1202		int h = spread(k.hashCode());
1203	<	V val = null;
1204	<	Node node = null;
1205	<	boolean added = false;
486	<	boolean validated = false;
487	<	Node[] tab = table;
488	<	do {
489	<	Node e; int i;
1203	>	int count = 0;
1204	>	for (Node[] tab = table;;) {
1205	>	int i; Node f; int fh; Object fk;
1206		if (tab == null)
1207	<	tab = grow(0);
1208	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1209	<	if (node == null)
1210	<	node = new Node(h, k, null, null);
1211	<	synchronized(node) {
1212	<	if (casTabAt(tab, i, null, node)) {
1213	<	validated = true;
1214	<	try {
1215	<	val = f.map(k);
1216	<	if (val != null) {
1217	<	node.val = val;
1218	<	added = true;
1207	>	tab = initTable();
1208	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1209	>	if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1210	>	break;                   // no lock when adding to empty bin
1211	>	}
1212	>	else if ((fh = f.hash) == MOVED) {
1213	>	if ((fk = f.key) instanceof TreeBin) {
1214	>	TreeBin t = (TreeBin)fk;
1215	>	Object oldVal = null;
1216	>	t.acquire(0);
1217	>	try {
1218	>	if (tabAt(tab, i) == f) {
1219	>	count = 2;
1220	>	TreeNode p = t.putTreeNode(h, k, v);
1221	>	if (p != null) {
1222	>	oldVal = p.val;
1223	>	p.val = v;
1224		}
504	–	} finally {
505	–	if (!added)
506	–	setTabAt(tab, i, null);
1225		}
1226	+	} finally {
1227	+	t.release(0);
1228	+	}
1229	+	if (count != 0) {
1230	+	if (oldVal != null)
1231	+	return oldVal;
1232	+	break;
1233	+	}
1234	+	}
1235	+	else
1236	+	tab = (Node[])fk;
1237	+	}
1238	+	else if ((fh & LOCKED) != 0) {
1239	+	checkForResize();
1240	+	f.tryAwaitLock(tab, i);
1241	+	}
1242	+	else if (f.casHash(fh, fh | LOCKED)) {
1243	+	Object oldVal = null;
1244	+	try {                        // needed in case equals() throws
1245	+	if (tabAt(tab, i) == f) {
1246	+	count = 1;
1247	+	for (Node e = f;; ++count) {
1248	+	Object ek, ev;
1249	+	if ((e.hash & HASH_BITS) == h &&
1250	+	(ev = e.val) != null &&
1251	+	((ek = e.key) == k || k.equals(ek))) {
1252	+	oldVal = ev;
1253	+	e.val = v;
1254	+	break;
1255	+	}
1256	+	Node last = e;
1257	+	if ((e = e.next) == null) {
1258	+	last.next = new Node(h, k, v, null);
1259	+	if (count >= TREE_THRESHOLD)
1260	+	replaceWithTreeBin(tab, i, k);
1261	+	break;
1262	+	}
1263	+	}
1264	+	}
1265	+	} finally {                  // unlock and signal if needed
1266	+	if (!f.casHash(fh | LOCKED, fh)) {
1267	+	f.hash = fh;
1268	+	synchronized (f) { f.notifyAll(); };
1269	+	}
1270	+	}
1271	+	if (count != 0) {
1272	+	if (oldVal != null)
1273	+	return oldVal;
1274	+	if (tab.length <= 64)
1275	+	count = 2;
1276	+	break;
1277	+	}
1278	+	}
1279	+	}
1280	+	counter.add(1L);
1281	+	if (count > 1)
1282	+	checkForResize();
1283	+	return null;
1284	+	}
1285	+
1286	+	/** Implementation for putIfAbsent */
1287	+	private final Object internalPutIfAbsent(Object k, Object v) {
1288	+	int h = spread(k.hashCode());
1289	+	int count = 0;
1290	+	for (Node[] tab = table;;) {
1291	+	int i; Node f; int fh; Object fk, fv;
1292	+	if (tab == null)
1293	+	tab = initTable();
1294	+	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1295	+	if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1296	+	break;
1297	+	}
1298	+	else if ((fh = f.hash) == MOVED) {
1299	+	if ((fk = f.key) instanceof TreeBin) {
1300	+	TreeBin t = (TreeBin)fk;
1301	+	Object oldVal = null;
1302	+	t.acquire(0);
1303	+	try {
1304	+	if (tabAt(tab, i) == f) {
1305	+	count = 2;
1306	+	TreeNode p = t.putTreeNode(h, k, v);
1307	+	if (p != null)
1308	+	oldVal = p.val;
1309	+	}
1310	+	} finally {
1311	+	t.release(0);
1312	+	}
1313	+	if (count != 0) {
1314	+	if (oldVal != null)
1315	+	return oldVal;
1316	+	break;
1317		}
1318		}
1319	+	else
1320	+	tab = (Node[])fk;
1321		}
1322	<	else if (e.hash < 0)
1323	<	tab = (Node[])e.key;
1322	>	else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1323	>	((fk = f.key) == k || k.equals(fk)))
1324	>	return fv;
1325		else {
1326	<	boolean checkSize = false;
1327	<	synchronized(e) {
1328	<	Node first = e;
517	<	for (;;) {
1326	>	Node g = f.next;
1327	>	if (g != null) { // at least 2 nodes -- search and maybe resize
1328	>	for (Node e = g;;) {
1329		Object ek, ev;
1330	<	if ((ev = e.val) == null)
1330	>	if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1331	>	((ek = e.key) == k || k.equals(ek)))
1332	>	return ev;
1333	>	if ((e = e.next) == null) {
1334	>	checkForResize();
1335		break;
1336	<	if (e.hash == h && (ek = e.key) != null &&
1337	<	(k == ek || k.equals(ek))) {
1338	<	if (tabAt(tab, i) == first) {
1339	<	validated = true;
1340	<	val = (V)ev;
1336	>	}
1337	>	}
1338	>	}
1339	>	if (((fh = f.hash) & LOCKED) != 0) {
1340	>	checkForResize();
1341	>	f.tryAwaitLock(tab, i);
1342	>	}
1343	>	else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1344	>	Object oldVal = null;
1345	>	try {
1346	>	if (tabAt(tab, i) == f) {
1347	>	count = 1;
1348	>	for (Node e = f;; ++count) {
1349	>	Object ek, ev;
1350	>	if ((e.hash & HASH_BITS) == h &&
1351	>	(ev = e.val) != null &&
1352	>	((ek = e.key) == k || k.equals(ek))) {
1353	>	oldVal = ev;
1354	>	break;
1355	>	}
1356	>	Node last = e;
1357	>	if ((e = e.next) == null) {
1358	>	last.next = new Node(h, k, v, null);
1359	>	if (count >= TREE_THRESHOLD)
1360	>	replaceWithTreeBin(tab, i, k);
1361	>	break;
1362	>	}
1363		}
527	–	break;
1364		}
1365	<	Node last = e;
1365	>	} finally {
1366	>	if (!f.casHash(fh | LOCKED, fh)) {
1367	>	f.hash = fh;
1368	>	synchronized (f) { f.notifyAll(); };
1369	>	}
1370	>	}
1371	>	if (count != 0) {
1372	>	if (oldVal != null)
1373	>	return oldVal;
1374	>	if (tab.length <= 64)
1375	>	count = 2;
1376	>	break;
1377	>	}
1378	>	}
1379	>	}
1380	>	}
1381	>	counter.add(1L);
1382	>	if (count > 1)
1383	>	checkForResize();
1384	>	return null;
1385	>	}
1386	>
1387	>	/** Implementation for computeIfAbsent */
1388	>	private final Object internalComputeIfAbsent(K k,
1389	>	MappingFunction<? super K, ?> mf) {
1390	>	int h = spread(k.hashCode());
1391	>	Object val = null;
1392	>	int count = 0;
1393	>	for (Node[] tab = table;;) {
1394	>	Node f; int i, fh; Object fk, fv;
1395	>	if (tab == null)
1396	>	tab = initTable();
1397	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1398	>	Node node = new Node(fh = h | LOCKED, k, null, null);
1399	>	if (casTabAt(tab, i, null, node)) {
1400	>	count = 1;
1401	>	try {
1402	>	if ((val = mf.map(k)) != null)
1403	>	node.val = val;
1404	>	} finally {
1405	>	if (val == null)
1406	>	setTabAt(tab, i, null);
1407	>	if (!node.casHash(fh, h)) {
1408	>	node.hash = h;
1409	>	synchronized (node) { node.notifyAll(); };
1410	>	}
1411	>	}
1412	>	}
1413	>	if (count != 0)
1414	>	break;
1415	>	}
1416	>	else if ((fh = f.hash) == MOVED) {
1417	>	if ((fk = f.key) instanceof TreeBin) {
1418	>	TreeBin t = (TreeBin)fk;
1419	>	boolean added = false;
1420	>	t.acquire(0);
1421	>	try {
1422	>	if (tabAt(tab, i) == f) {
1423	>	count = 1;
1424	>	TreeNode p = t.getTreeNode(h, k, t.root);
1425	>	if (p != null)
1426	>	val = p.val;
1427	>	else if ((val = mf.map(k)) != null) {
1428	>	added = true;
1429	>	count = 2;
1430	>	t.putTreeNode(h, k, val);
1431	>	}
1432	>	}
1433	>	} finally {
1434	>	t.release(0);
1435	>	}
1436	>	if (count != 0) {
1437	>	if (!added)
1438	>	return val;
1439	>	break;
1440	>	}
1441	>	}
1442	>	else
1443	>	tab = (Node[])fk;
1444	>	}
1445	>	else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1446	>	((fk = f.key) == k || k.equals(fk)))
1447	>	return fv;
1448	>	else {
1449	>	Node g = f.next;
1450	>	if (g != null) {
1451	>	for (Node e = g;;) {
1452	>	Object ek, ev;
1453	>	if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
1454	>	((ek = e.key) == k || k.equals(ek)))
1455	>	return ev;
1456		if ((e = e.next) == null) {
1457	<	if (tabAt(tab, i) == first) {
1458	<	validated = true;
1459	<	if ((val = f.map(k)) != null) {
1460	<	if (node == null)
1461	<	node = new Node(h, k, val, null);
1462	<	else
1463	<	node.val = val;
1464	<	last.next = node;
1465	<	if (last != first)
1466	<	checkSize = true;
1467	<	added = true;
1457	>	checkForResize();
1458	>	break;
1459	>	}
1460	>	}
1461	>	}
1462	>	if (((fh = f.hash) & LOCKED) != 0) {
1463	>	checkForResize();
1464	>	f.tryAwaitLock(tab, i);
1465	>	}
1466	>	else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1467	>	boolean added = false;
1468	>	try {
1469	>	if (tabAt(tab, i) == f) {
1470	>	count = 1;
1471	>	for (Node e = f;; ++count) {
1472	>	Object ek, ev;
1473	>	if ((e.hash & HASH_BITS) == h &&
1474	>	(ev = e.val) != null &&
1475	>	((ek = e.key) == k || k.equals(ek))) {
1476	>	val = ev;
1477	>	break;
1478	>	}
1479	>	Node last = e;
1480	>	if ((e = e.next) == null) {
1481	>	if ((val = mf.map(k)) != null) {
1482	>	added = true;
1483	>	last.next = new Node(h, k, val, null);
1484	>	if (count >= TREE_THRESHOLD)
1485	>	replaceWithTreeBin(tab, i, k);
1486	>	}
1487	>	break;
1488		}
1489		}
544	–	break;
1490		}
1491	+	} finally {
1492	+	if (!f.casHash(fh | LOCKED, fh)) {
1493	+	f.hash = fh;
1494	+	synchronized (f) { f.notifyAll(); };
1495	+	}
1496	+	}
1497	+	if (count != 0) {
1498	+	if (!added)
1499	+	return val;
1500	+	if (tab.length <= 64)
1501	+	count = 2;
1502	+	break;
1503		}
1504		}
1505	<	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
1506	<	resizing == 0 && counter.sum() >= threshold)
1507	<	grow(0);
1508	<	}
1509	<	} while (!validated);
1510	<	if (added)
1511	<	counter.increment();
1505	>	}
1506	>	}
1507	>	if (val == null)
1508	>	throw new NullPointerException();
1509	>	counter.add(1L);
1510	>	if (count > 1)
1511	>	checkForResize();
1512		return val;
1513		}
1514
1515	<	/*
1516	<	* Reclassifies nodes in each bin to new table.  Because we are
1517	<	* using power-of-two expansion, the elements from each bin must
1518	<	* either stay at same index, or move with a power of two
1519	<	* offset. We eliminate unnecessary node creation by catching
1520	<	* cases where old nodes can be reused because their next fields
1521	<	* won't change.  Statistically, at the default threshold, only
1522	<	* about one-sixth of them need cloning when a table doubles. The
1523	<	* nodes they replace will be garbage collectable as soon as they
1524	<	* are no longer referenced by any reader thread that may be in
1525	<	* the midst of concurrently traversing table.
1526	<	*
1527	<	* Transfers are done from the bottom up to preserve iterator
1528	<	* traversability. On each step, the old bin is locked,
1529	<	* moved/copied, and then replaced with a forwarding node.
1530	<	*/
1531	<	private static final void transfer(Node[] tab, Node[] nextTab) {
1532	<	int n = tab.length;
1533	<	int mask = nextTab.length - 1;
1534	<	Node fwd = new Node(MOVED, nextTab, null, null);
1535	<	for (int i = n - 1; i >= 0; --i) {
1536	<	for (Node e;;) {
1537	<	if ((e = tabAt(tab, i)) == null) {
1538	<	if (casTabAt(tab, i, e, fwd))
1539	<	break;
1515	>	/** Implementation for compute */
1516	>	@SuppressWarnings("unchecked")
1517	>	private final Object internalCompute(K k,
1518	>	RemappingFunction<? super K, V> mf) {
1519	>	int h = spread(k.hashCode());
1520	>	Object val = null;
1521	>	boolean added = false;
1522	>	int count = 0;
1523	>	for (Node[] tab = table;;) {
1524	>	Node f; int i, fh; Object fk;
1525	>	if (tab == null)
1526	>	tab = initTable();
1527	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1528	>	Node node = new Node(fh = h | LOCKED, k, null, null);
1529	>	if (casTabAt(tab, i, null, node)) {
1530	>	try {
1531	>	count = 1;
1532	>	if ((val = mf.remap(k, null)) != null) {
1533	>	node.val = val;
1534	>	added = true;
1535	>	}
1536	>	} finally {
1537	>	if (!added)
1538	>	setTabAt(tab, i, null);
1539	>	if (!node.casHash(fh, h)) {
1540	>	node.hash = h;
1541	>	synchronized (node) { node.notifyAll(); };
1542	>	}
1543	>	}
1544		}
1545	<	else {
1546	<	boolean validated = false;
1547	<	synchronized(e) {
1548	<	int idx = e.hash & mask;
1549	<	Node lastRun = e;
1550	<	for (Node p = e.next; p != null; p = p.next) {
1551	<	int j = p.hash & mask;
1552	<	if (j != idx) {
1553	<	idx = j;
1554	<	lastRun = p;
1545	>	if (count != 0)
1546	>	break;
1547	>	}
1548	>	else if ((fh = f.hash) == MOVED) {
1549	>	if ((fk = f.key) instanceof TreeBin) {
1550	>	TreeBin t = (TreeBin)fk;
1551	>	t.acquire(0);
1552	>	try {
1553	>	if (tabAt(tab, i) == f) {
1554	>	count = 1;
1555	>	TreeNode p = t.getTreeNode(h, k, t.root);
1556	>	Object pv = (p == null)? null : p.val;
1557	>	if ((val = mf.remap(k, (V)pv)) != null) {
1558	>	if (p != null)
1559	>	p.val = val;
1560	>	else {
1561	>	count = 2;
1562	>	added = true;
1563	>	t.putTreeNode(h, k, val);
1564	>	}
1565		}
1566		}
1567	<	if (tabAt(tab, i) == e) {
1568	<	validated = true;
1569	<	setTabAt(nextTab, idx, lastRun);
1570	<	for (Node p = e; p != lastRun; p = p.next) {
1571	<	int h = p.hash;
1572	<	int j = h & mask;
1573	<	Object pk = p.key, pv = p.val;
1574	<	Node r = tabAt(nextTab, j);
1575	<	setTabAt(nextTab, j, new Node(h, pk, pv, r));
1567	>	} finally {
1568	>	t.release(0);
1569	>	}
1570	>	if (count != 0)
1571	>	break;
1572	>	}
1573	>	else
1574	>	tab = (Node[])fk;
1575	>	}
1576	>	else if ((fh & LOCKED) != 0) {
1577	>	checkForResize();
1578	>	f.tryAwaitLock(tab, i);
1579	>	}
1580	>	else if (f.casHash(fh, fh | LOCKED)) {
1581	>	try {
1582	>	if (tabAt(tab, i) == f) {
1583	>	count = 1;
1584	>	for (Node e = f;; ++count) {
1585	>	Object ek, ev;
1586	>	if ((e.hash & HASH_BITS) == h &&
1587	>	(ev = e.val) != null &&
1588	>	((ek = e.key) == k || k.equals(ek))) {
1589	>	val = mf.remap(k, (V)ev);
1590	>	if (val != null)
1591	>	e.val = val;
1592	>	break;
1593	>	}
1594	>	Node last = e;
1595	>	if ((e = e.next) == null) {
1596	>	if ((val = mf.remap(k, null)) != null) {
1597	>	last.next = new Node(h, k, val, null);
1598	>	added = true;
1599	>	if (count >= TREE_THRESHOLD)
1600	>	replaceWithTreeBin(tab, i, k);
1601	>	}
1602	>	break;
1603		}
606	–	setTabAt(tab, i, fwd);
1604		}
1605		}
1606	<	if (validated)
1607	<	break;
1606	>	} finally {
1607	>	if (!f.casHash(fh | LOCKED, fh)) {
1608	>	f.hash = fh;
1609	>	synchronized (f) { f.notifyAll(); };
1610	>	}
1611	>	}
1612	>	if (count != 0) {
1613	>	if (tab.length <= 64)
1614	>	count = 2;
1615	>	break;
1616		}
1617		}
1618		}
1619	+	if (val == null)
1620	+	throw new NullPointerException();
1621	+	if (added) {
1622	+	counter.add(1L);
1623	+	if (count > 1)
1624	+	checkForResize();
1625	+	}
1626	+	return val;
1627		}
1628
1629	<	/**
1630	<	* If not already resizing, initializes or creates next table and
1631	<	* transfers bins. Rechecks occupancy after a transfer to see if
1632	<	* another resize is already needed because resizings are lagging
1633	<	* additions.
1634	<	*
1635	<	* @param sizeHint overridden capacity target (nonzero only from putAll)
1636	<	* @return current table
1637	<	*/
1638	<	private final Node[] grow(int sizeHint) {
1639	<	Node[] tab;
1640	<	if (resizing == 0 &&
1641	<	UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
1642	<	try {
1643	<	for (;;) {
1644	<	int cap, n;
1645	<	if ((tab = table) == null) {
1646	<	int c = initCap;
1647	<	if (c < sizeHint)
1648	<	c = sizeHint;
1649	<	if (c == DEFAULT_CAPACITY)
1650	<	cap = c;
638	<	else if (c >= MAXIMUM_CAPACITY)
639	<	cap = MAXIMUM_CAPACITY;
640	<	else {
641	<	cap = MINIMUM_CAPACITY;
642	<	while (cap < c)
643	<	cap <<= 1;
1629	>	/** Implementation for putAll */
1630	>	private final void internalPutAll(Map<?, ?> m) {
1631	>	tryPresize(m.size());
1632	>	long delta = 0L;     // number of uncommitted additions
1633	>	boolean npe = false; // to throw exception on exit for nulls
1634	>	try {                // to clean up counts on other exceptions
1635	>	for (Map.Entry<?, ?> entry : m.entrySet()) {
1636	>	Object k, v;
1637	>	if (entry == null || (k = entry.getKey()) == null ||
1638	>	(v = entry.getValue()) == null) {
1639	>	npe = true;
1640	>	break;
1641	>	}
1642	>	int h = spread(k.hashCode());
1643	>	for (Node[] tab = table;;) {
1644	>	int i; Node f; int fh; Object fk;
1645	>	if (tab == null)
1646	>	tab = initTable();
1647	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
1648	>	if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
1649	>	++delta;
1650	>	break;
1651		}
1652		}
1653	<	else if ((n = tab.length) < MAXIMUM_CAPACITY &&
1654	<	(sizeHint <= 0 || n < sizeHint))
1655	<	cap = n << 1;
1656	<	else
1657	<	break;
1658	<	threshold = (int)(cap * loadFactor) - THRESHOLD_OFFSET;
1659	<	Node[] nextTab = new Node[cap];
1660	<	if (tab != null)
1661	<	transfer(tab, nextTab);
1662	<	table = nextTab;
1663	<	if (tab == null || counter.sum() < threshold) {
1664	<	tab = nextTab;
1665	<	break;
1653	>	else if ((fh = f.hash) == MOVED) {
1654	>	if ((fk = f.key) instanceof TreeBin) {
1655	>	TreeBin t = (TreeBin)fk;
1656	>	boolean validated = false;
1657	>	t.acquire(0);
1658	>	try {
1659	>	if (tabAt(tab, i) == f) {
1660	>	validated = true;
1661	>	TreeNode p = t.getTreeNode(h, k, t.root);
1662	>	if (p != null)
1663	>	p.val = v;
1664	>	else {
1665	>	t.putTreeNode(h, k, v);
1666	>	++delta;
1667	>	}
1668	>	}
1669	>	} finally {
1670	>	t.release(0);
1671	>	}
1672	>	if (validated)
1673	>	break;
1674	>	}
1675	>	else
1676	>	tab = (Node[])fk;
1677	>	}
1678	>	else if ((fh & LOCKED) != 0) {
1679	>	counter.add(delta);
1680	>	delta = 0L;
1681	>	checkForResize();
1682	>	f.tryAwaitLock(tab, i);
1683	>	}
1684	>	else if (f.casHash(fh, fh | LOCKED)) {
1685	>	int count = 0;
1686	>	try {
1687	>	if (tabAt(tab, i) == f) {
1688	>	count = 1;
1689	>	for (Node e = f;; ++count) {
1690	>	Object ek, ev;
1691	>	if ((e.hash & HASH_BITS) == h &&
1692	>	(ev = e.val) != null &&
1693	>	((ek = e.key) == k || k.equals(ek))) {
1694	>	e.val = v;
1695	>	break;
1696	>	}
1697	>	Node last = e;
1698	>	if ((e = e.next) == null) {
1699	>	++delta;
1700	>	last.next = new Node(h, k, v, null);
1701	>	if (count >= TREE_THRESHOLD)
1702	>	replaceWithTreeBin(tab, i, k);
1703	>	break;
1704	>	}
1705	>	}
1706	>	}
1707	>	} finally {
1708	>	if (!f.casHash(fh | LOCKED, fh)) {
1709	>	f.hash = fh;
1710	>	synchronized (f) { f.notifyAll(); };
1711	>	}
1712	>	}
1713	>	if (count != 0) {
1714	>	if (count > 1) {
1715	>	counter.add(delta);
1716	>	delta = 0L;
1717	>	checkForResize();
1718	>	}
1719	>	break;
1720	>	}
1721		}
1722		}
661	–	} finally {
662	–	resizing = 0;
1723		}
1724	+	} finally {
1725	+	if (delta != 0)
1726	+	counter.add(delta);
1727		}
1728	<	else if ((tab = table) == null)
1729	<	Thread.yield(); // lost initialization race; just spin
667	<	return tab;
1728	>	if (npe)
1729	>	throw new NullPointerException();
1730		}
1731
1732	+	/* ---------------- Table Initialization and Resizing -------------- */
1733	+
1734		/**
1735	<	* Implements putAll and constructor with Map argument. Tries to
1736	<	* first override initial capacity or grow (once) based on map
673	<	* size to pre-allocate table space.
1735	>	* Returns a power of two table size for the given desired capacity.
1736	>	* See Hackers Delight, sec 3.2
1737		*/
1738	<	private final void internalPutAll(Map<? extends K, ? extends V> m) {
1739	<	int s = m.size();
1740	<	grow((s >= (MAXIMUM_CAPACITY >>> 1))? s : s + (s >>> 1));
1741	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
1742	<	Object k = e.getKey();
1743	<	Object v = e.getValue();
1744	<	if (k == null || v == null)
1745	<	throw new NullPointerException();
683	<	internalPut(k, v, true);
684	<	}
1738	>	private static final int tableSizeFor(int c) {
1739	>	int n = c - 1;
1740	>	n |= n >>> 1;
1741	>	n |= n >>> 2;
1742	>	n |= n >>> 4;
1743	>	n |= n >>> 8;
1744	>	n |= n >>> 16;
1745	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1746		}
1747
1748		/**
1749	<	* Implements clear. Steps through each bin, removing all nodes.
1749	>	* Initializes table, using the size recorded in sizeCtl.
1750		*/
1751	<	private final void internalClear() {
1752	<	long delta = 0L; // negative of number of deletions
1753	<	int i = 0;
1754	<	Node[] tab = table;
1755	<	while (tab != null && i < tab.length) {
1756	<	Node e = tabAt(tab, i);
1757	<	if (e == null)
1758	<	++i;
1759	<	else if (e.hash < 0)
1760	<	tab = (Node[])e.key;
1761	<	else {
701	<	boolean validated = false;
702	<	synchronized(e) {
703	<	if (tabAt(tab, i) == e) {
704	<	validated = true;
705	<	do {
706	<	if (e.val != null) {
707	<	e.val = null;
708	<	--delta;
709	<	}
710	<	} while ((e = e.next) != null);
711	<	setTabAt(tab, i, null);
1751	>	private final Node[] initTable() {
1752	>	Node[] tab; int sc;
1753	>	while ((tab = table) == null) {
1754	>	if ((sc = sizeCtl) < 0)
1755	>	Thread.yield(); // lost initialization race; just spin
1756	>	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1757	>	try {
1758	>	if ((tab = table) == null) {
1759	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1760	>	tab = table = new Node[n];
1761	>	sc = n - (n >>> 2);
1762		}
1763	+	} finally {
1764	+	sizeCtl = sc;
1765		}
1766	<	if (validated)
715	<	++i;
1766	>	break;
1767		}
1768		}
1769	<	counter.add(delta);
1769	>	return tab;
1770		}
1771
1772		/**
1773	<	* Base class for key, value, and entry iterators, plus internal
1774	<	* implementations of public traversal-based methods, to avoid
1775	<	* duplicating traversal code.
1776	<	*/
1777	<	class HashIterator {
1778	<	private Node next;          // the next entry to return
1779	<	private Node[] tab;         // current table; updated if resized
1780	<	private Node lastReturned;  // the last entry returned, for remove
1781	<	private Object nextVal;     // cached value of next
1782	<	private int index;          // index of bin to use next
1783	<	private int baseIndex;      // current index of initial table
1784	<	private final int baseSize; // initial table size
1785	<
1786	<	HashIterator() {
1787	<	Node[] t = tab = table;
1788	<	if (t == null)
1789	<	baseSize = 0;
1790	<	else {
740	<	baseSize = t.length;
741	<	advance(null);
1773	>	* If table is too small and not already resizing, creates next
1774	>	* table and transfers bins.  Rechecks occupancy after a transfer
1775	>	* to see if another resize is already needed because resizings
1776	>	* are lagging additions.
1777	>	*/
1778	>	private final void checkForResize() {
1779	>	Node[] tab; int n, sc;
1780	>	while ((tab = table) != null &&
1781	>	(n = tab.length) < MAXIMUM_CAPACITY &&
1782	>	(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
1783	>	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1784	>	try {
1785	>	if (tab == table) {
1786	>	table = rebuild(tab);
1787	>	sc = (n << 1) - (n >>> 1);
1788	>	}
1789	>	} finally {
1790	>	sizeCtl = sc;
1791		}
1792		}
1793	+	}
1794
1795	<	public final boolean hasNext()         { return next != null; }
1796	<	public final boolean hasMoreElements() { return next != null; }
1795	>	/**
1796	>	* Tries to presize table to accommodate the given number of elements.
1797	>	*
1798	>	* @param size number of elements (doesn't need to be perfectly accurate)
1799	>	*/
1800	>	private final void tryPresize(int size) {
1801	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1802	>	tableSizeFor(size + (size >>> 1) + 1);
1803	>	int sc;
1804	>	while ((sc = sizeCtl) >= 0) {
1805	>	Node[] tab = table; int n;
1806	>	if (tab == null || (n = tab.length) == 0) {
1807	>	n = (sc > c) ? sc : c;
1808	>	if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1809	>	try {
1810	>	if (table == tab) {
1811	>	table = new Node[n];
1812	>	sc = n - (n >>> 2);
1813	>	}
1814	>	} finally {
1815	>	sizeCtl = sc;
1816	>	}
1817	>	}
1818	>	}
1819	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1820	>	break;
1821	>	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1822	>	try {
1823	>	if (table == tab) {
1824	>	table = rebuild(tab);
1825	>	sc = (n << 1) - (n >>> 1);
1826	>	}
1827	>	} finally {
1828	>	sizeCtl = sc;
1829	>	}
1830	>	}
1831	>	}
1832	>	}
1833
1834	<	/**
1835	<	* Advances next.  Normally, iteration proceeds bin-by-bin
1836	<	* traversing lists.  However, if the table has been resized,
1837	<	* then all future steps must traverse both the bin at the
1838	<	* current index as well as at (index + baseSize); and so on
1839	<	* for further resizings. To paranoically cope with potential
1840	<	* (improper) sharing of iterators across threads, table reads
1841	<	* are bounds-checked.
1842	<	*/
1843	<	final void advance(Node e) {
1844	<	for (;;) {
1845	<	Node[] t; int i; // for bounds checks
1846	<	if (e != null) {
1847	<	Object ek = e.key, ev = e.val;
1848	<	if (ev != null && ek != null) {
1849	<	nextVal = ev;
1850	<	next = e;
1851	<	break;
1834	>	/*
1835	>	* Moves and/or copies the nodes in each bin to new table. See
1836	>	* above for explanation.
1837	>	*
1838	>	* @return the new table
1839	>	*/
1840	>	private static final Node[] rebuild(Node[] tab) {
1841	>	int n = tab.length;
1842	>	Node[] nextTab = new Node[n << 1];
1843	>	Node fwd = new Node(MOVED, nextTab, null, null);
1844	>	int[] buffer = null;       // holds bins to revisit; null until needed
1845	>	Node rev = null;           // reverse forwarder; null until needed
1846	>	int nbuffered = 0;         // the number of bins in buffer list
1847	>	int bufferIndex = 0;       // buffer index of current buffered bin
1848	>	int bin = n - 1;           // current non-buffered bin or -1 if none
1849	>
1850	>	for (int i = bin;;) {      // start upwards sweep
1851	>	int fh; Node f;
1852	>	if ((f = tabAt(tab, i)) == null) {
1853	>	if (bin >= 0) {    // no lock needed (or available)
1854	>	if (!casTabAt(tab, i, f, fwd))
1855	>	continue;
1856	>	}
1857	>	else {             // transiently use a locked forwarding node
1858	>	Node g = new Node(MOVED|LOCKED, nextTab, null, null);
1859	>	if (!casTabAt(tab, i, f, g))
1860	>	continue;
1861	>	setTabAt(nextTab, i, null);
1862	>	setTabAt(nextTab, i + n, null);
1863	>	setTabAt(tab, i, fwd);
1864	>	if (!g.casHash(MOVED|LOCKED, MOVED)) {
1865	>	g.hash = MOVED;
1866	>	synchronized (g) { g.notifyAll(); }
1867		}
767	–	e = e.next;
1868		}
1869	<	else if (baseIndex < baseSize && (t = tab) != null &&
1870	<	t.length > (i = index) && i >= 0) {
1871	<	if ((e = tabAt(t, i)) != null && e.hash < 0) {
1872	<	tab = (Node[])e.key;
1873	<	e = null;
1869	>	}
1870	>	else if ((fh = f.hash) == MOVED) {
1871	>	Object fk = f.key;
1872	>	if (fk instanceof TreeBin) {
1873	>	TreeBin t = (TreeBin)fk;
1874	>	boolean validated = false;
1875	>	t.acquire(0);
1876	>	try {
1877	>	if (tabAt(tab, i) == f) {
1878	>	validated = true;
1879	>	splitTreeBin(nextTab, i, t);
1880	>	setTabAt(tab, i, fwd);
1881	>	}
1882	>	} finally {
1883	>	t.release(0);
1884		}
1885	<	else if (i + baseSize < t.length)
1886	<	index += baseSize;    // visit forwarded upper slots
777	<	else
778	<	index = ++baseIndex;
1885	>	if (!validated)
1886	>	continue;
1887		}
1888	<	else {
1889	<	next = null;
1890	<	break;
1888	>	}
1889	>	else if ((fh & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
1890	>	boolean validated = false;
1891	>	try {              // split to lo and hi lists; copying as needed
1892	>	if (tabAt(tab, i) == f) {
1893	>	validated = true;
1894	>	splitBin(nextTab, i, f);
1895	>	setTabAt(tab, i, fwd);
1896	>	}
1897	>	} finally {
1898	>	if (!f.casHash(fh | LOCKED, fh)) {
1899	>	f.hash = fh;
1900	>	synchronized (f) { f.notifyAll(); };
1901	>	}
1902		}
1903	+	if (!validated)
1904	+	continue;
1905	+	}
1906	+	else {
1907	+	if (buffer == null) // initialize buffer for revisits
1908	+	buffer = new int[TRANSFER_BUFFER_SIZE];
1909	+	if (bin < 0 && bufferIndex > 0) {
1910	+	int j = buffer[--bufferIndex];
1911	+	buffer[bufferIndex] = i;
1912	+	i = j;         // swap with another bin
1913	+	continue;
1914	+	}
1915	+	if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
1916	+	f.tryAwaitLock(tab, i);
1917	+	continue;      // no other options -- block
1918	+	}
1919	+	if (rev == null)   // initialize reverse-forwarder
1920	+	rev = new Node(MOVED, tab, null, null);
1921	+	if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
1922	+	continue;      // recheck before adding to list
1923	+	buffer[nbuffered++] = i;
1924	+	setTabAt(nextTab, i, rev);     // install place-holders
1925	+	setTabAt(nextTab, i + n, rev);
1926		}
785	–	}
1927
1928	<	final Object nextKey() {
1929	<	Node e = next;
1930	<	if (e == null)
1931	<	throw new NoSuchElementException();
1932	<	Object k = e.key;
1933	<	advance((lastReturned = e).next);
1934	<	return k;
1928	>	if (bin > 0)
1929	>	i = --bin;
1930	>	else if (buffer != null && nbuffered > 0) {
1931	>	bin = -1;
1932	>	i = buffer[bufferIndex = --nbuffered];
1933	>	}
1934	>	else
1935	>	return nextTab;
1936		}
1937	+	}
1938
1939	<	final Object nextValue() {
1940	<	Node e = next;
1941	<	if (e == null)
1942	<	throw new NoSuchElementException();
1943	<	Object v = nextVal;
1944	<	advance((lastReturned = e).next);
1945	<	return v;
1939	>	/**
1940	>	* Split a normal bin with list headed by e into lo and hi parts;
1941	>	* install in given table
1942	>	*/
1943	>	private static void splitBin(Node[] nextTab, int i, Node e) {
1944	>	int bit = nextTab.length >>> 1; // bit to split on
1945	>	int runBit = e.hash & bit;
1946	>	Node lastRun = e, lo = null, hi = null;
1947	>	for (Node p = e.next; p != null; p = p.next) {
1948	>	int b = p.hash & bit;
1949	>	if (b != runBit) {
1950	>	runBit = b;
1951	>	lastRun = p;
1952	>	}
1953		}
1954	+	if (runBit == 0)
1955	+	lo = lastRun;
1956	+	else
1957	+	hi = lastRun;
1958	+	for (Node p = e; p != lastRun; p = p.next) {
1959	+	int ph = p.hash & HASH_BITS;
1960	+	Object pk = p.key, pv = p.val;
1961	+	if ((ph & bit) == 0)
1962	+	lo = new Node(ph, pk, pv, lo);
1963	+	else
1964	+	hi = new Node(ph, pk, pv, hi);
1965	+	}
1966	+	setTabAt(nextTab, i, lo);
1967	+	setTabAt(nextTab, i + bit, hi);
1968	+	}
1969
1970	<	final WriteThroughEntry nextEntry() {
1971	<	Node e = next;
1972	<	if (e == null)
1973	<	throw new NoSuchElementException();
1974	<	WriteThroughEntry entry =
1975	<	new WriteThroughEntry(e.key, nextVal);
1976	<	advance((lastReturned = e).next);
1977	<	return entry;
1970	>	/**
1971	>	* Split a tree bin into lo and hi parts; install in given table
1972	>	*/
1973	>	private static void splitTreeBin(Node[] nextTab, int i, TreeBin t) {
1974	>	int bit = nextTab.length >>> 1;
1975	>	TreeBin lt = new TreeBin();
1976	>	TreeBin ht = new TreeBin();
1977	>	int lc = 0, hc = 0;
1978	>	for (Node e = t.first; e != null; e = e.next) {
1979	>	int h = e.hash & HASH_BITS;
1980	>	Object k = e.key, v = e.val;
1981	>	if ((h & bit) == 0) {
1982	>	++lc;
1983	>	lt.putTreeNode(h, k, v);
1984	>	}
1985	>	else {
1986	>	++hc;
1987	>	ht.putTreeNode(h, k, v);
1988	>	}
1989		}
1990	<
1991	<	public final void remove() {
1992	<	if (lastReturned == null)
1993	<	throw new IllegalStateException();
1994	<	ConcurrentHashMapV8.this.remove(lastReturned.key);
819	<	lastReturned = null;
1990	>	Node ln, hn; // throw away trees if too small
1991	>	if (lc <= (TREE_THRESHOLD >>> 1)) {
1992	>	ln = null;
1993	>	for (Node p = lt.first; p != null; p = p.next)
1994	>	ln = new Node(p.hash, p.key, p.val, ln);
1995		}
1996	<
1997	<	/** Helper for serialization */
1998	<	final void writeEntries(java.io.ObjectOutputStream s)
1999	<	throws java.io.IOException {
2000	<	Node e;
2001	<	while ((e = next) != null) {
2002	<	s.writeObject(e.key);
828	<	s.writeObject(nextVal);
829	<	advance(e.next);
830	<	}
1996	>	else
1997	>	ln = new Node(MOVED, lt, null, null);
1998	>	setTabAt(nextTab, i, ln);
1999	>	if (hc <= (TREE_THRESHOLD >>> 1)) {
2000	>	hn = null;
2001	>	for (Node p = ht.first; p != null; p = p.next)
2002	>	hn = new Node(p.hash, p.key, p.val, hn);
2003		}
2004	+	else
2005	+	hn = new Node(MOVED, ht, null, null);
2006	+	setTabAt(nextTab, i + bit, hn);
2007	+	}
2008
2009	<	/** Helper for containsValue */
2010	<	final boolean containsVal(Object value) {
2011	<	if (value != null) {
2012	<	Node e;
2013	<	while ((e = next) != null) {
2014	<	Object v = nextVal;
2015	<	if (value == v || value.equals(v))
2016	<	return true;
2017	<	advance(e.next);
2009	>	/**
2010	>	* Implementation for clear. Steps through each bin, removing all
2011	>	* nodes.
2012	>	*/
2013	>	private final void internalClear() {
2014	>	long delta = 0L; // negative number of deletions
2015	>	int i = 0;
2016	>	Node[] tab = table;
2017	>	while (tab != null && i < tab.length) {
2018	>	int fh; Object fk;
2019	>	Node f = tabAt(tab, i);
2020	>	if (f == null)
2021	>	++i;
2022	>	else if ((fh = f.hash) == MOVED) {
2023	>	if ((fk = f.key) instanceof TreeBin) {
2024	>	TreeBin t = (TreeBin)fk;
2025	>	t.acquire(0);
2026	>	try {
2027	>	if (tabAt(tab, i) == f) {
2028	>	for (Node p = t.first; p != null; p = p.next) {
2029	>	p.val = null;
2030	>	--delta;
2031	>	}
2032	>	t.first = null;
2033	>	t.root = null;
2034	>	++i;
2035	>	}
2036	>	} finally {
2037	>	t.release(0);
2038	>	}
2039		}
2040	+	else
2041	+	tab = (Node[])fk;
2042		}
2043	<	return false;
2044	<	}
2045	<
2046	<	/** Helper for Map.hashCode */
2047	<	final int mapHashCode() {
2048	<	int h = 0;
2049	<	Node e;
2050	<	while ((e = next) != null) {
2051	<	h += e.key.hashCode() ^ nextVal.hashCode();
2052	<	advance(e.next);
2043	>	else if ((fh & LOCKED) != 0) {
2044	>	counter.add(delta); // opportunistically update count
2045	>	delta = 0L;
2046	>	f.tryAwaitLock(tab, i);
2047	>	}
2048	>	else if (f.casHash(fh, fh | LOCKED)) {
2049	>	try {
2050	>	if (tabAt(tab, i) == f) {
2051	>	for (Node e = f; e != null; e = e.next) {
2052	>	e.val = null;
2053	>	--delta;
2054	>	}
2055	>	setTabAt(tab, i, null);
2056	>	++i;
2057	>	}
2058	>	} finally {
2059	>	if (!f.casHash(fh | LOCKED, fh)) {
2060	>	f.hash = fh;
2061	>	synchronized (f) { f.notifyAll(); };
2062	>	}
2063	>	}
2064		}
855	–	return h;
2065		}
2066	+	if (delta != 0)
2067	+	counter.add(delta);
2068	+	}
2069
2070	<	/** Helper for Map.toString */
2071	<	final String mapToString() {
2072	<	Node e = next;
2073	<	if (e == null)
2074	<	return "{}";
2075	<	StringBuilder sb = new StringBuilder();
2076	<	sb.append('{');
2077	<	for (;;) {
2078	<	sb.append(e.key   == this ? "(this Map)" : e.key);
2079	<	sb.append('=');
2080	<	sb.append(nextVal == this ? "(this Map)" : nextVal);
2081	<	advance(e.next);
2082	<	if ((e = next) != null)
2083	<	sb.append(',').append(' ');
2084	<	else
2085	<	return sb.append('}').toString();
2086	<	}
2070	>	/* ----------------Table Traversal -------------- */
2071	>
2072	>	/**
2073	>	* Encapsulates traversal for methods such as containsValue; also
2074	>	* serves as a base class for other iterators.
2075	>	*
2076	>	* At each step, the iterator snapshots the key ("nextKey") and
2077	>	* value ("nextVal") of a valid node (i.e., one that, at point of
2078	>	* snapshot, has a non-null user value). Because val fields can
2079	>	* change (including to null, indicating deletion), field nextVal
2080	>	* might not be accurate at point of use, but still maintains the
2081	>	* weak consistency property of holding a value that was once
2082	>	* valid.
2083	>	*
2084	>	* Internal traversals directly access these fields, as in:
2085	>	* {@code while (it.next != null) { process(it.nextKey); it.advance(); }}
2086	>	*
2087	>	* Exported iterators (subclasses of ViewIterator) extract key,
2088	>	* value, or key-value pairs as return values of Iterator.next(),
2089	>	* and encapsulate the it.next check as hasNext();
2090	>	*
2091	>	* The iterator visits once each still-valid node that was
2092	>	* reachable upon iterator construction. It might miss some that
2093	>	* were added to a bin after the bin was visited, which is OK wrt
2094	>	* consistency guarantees. Maintaining this property in the face
2095	>	* of possible ongoing resizes requires a fair amount of
2096	>	* bookkeeping state that is difficult to optimize away amidst
2097	>	* volatile accesses.  Even so, traversal maintains reasonable
2098	>	* throughput.
2099	>	*
2100	>	* Normally, iteration proceeds bin-by-bin traversing lists.
2101	>	* However, if the table has been resized, then all future steps
2102	>	* must traverse both the bin at the current index as well as at
2103	>	* (index + baseSize); and so on for further resizings. To
2104	>	* paranoically cope with potential sharing by users of iterators
2105	>	* across threads, iteration terminates if a bounds checks fails
2106	>	* for a table read.
2107	>	*
2108	>	* The range-based constructor enables creation of parallel
2109	>	* range-splitting traversals. (Not yet implemented.)
2110	>	*/
2111	>	static class InternalIterator {
2112	>	Node next;           // the next entry to use
2113	>	Node last;           // the last entry used
2114	>	Object nextKey;      // cached key field of next
2115	>	Object nextVal;      // cached val field of next
2116	>	Node[] tab;          // current table; updated if resized
2117	>	int index;           // index of bin to use next
2118	>	int baseIndex;       // current index of initial table
2119	>	final int baseLimit; // index bound for initial table
2120	>	final int baseSize;  // initial table size
2121	>
2122	>	/** Creates iterator for all entries in the table. */
2123	>	InternalIterator(Node[] tab) {
2124	>	this.tab = tab;
2125	>	baseLimit = baseSize = (tab == null) ? 0 : tab.length;
2126	>	index = baseIndex = 0;
2127	>	next = null;
2128	>	advance();
2129	>	}
2130	>
2131	>	/** Creates iterator for the given range of the table */
2132	>	InternalIterator(Node[] tab, int lo, int hi) {
2133	>	this.tab = tab;
2134	>	baseSize = (tab == null) ? 0 : tab.length;
2135	>	baseLimit = (hi <= baseSize) ? hi : baseSize;
2136	>	index = baseIndex = (lo >= 0) ? lo : 0;
2137	>	next = null;
2138	>	advance();
2139	>	}
2140	>
2141	>	/** Advances next. See above for explanation. */
2142	>	final void advance() {
2143	>	Node e = last = next;
2144	>	outer: do {
2145	>	if (e != null)                  // advance past used/skipped node
2146	>	e = e.next;
2147	>	while (e == null) {             // get to next non-null bin
2148	>	Node[] t; int b, i, n; Object ek; // checks must use locals
2149	>	if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
2150	>	(t = tab) == null || i >= (n = t.length))
2151	>	break outer;
2152	>	else if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
2153	>	if ((ek = e.key) instanceof TreeBin)
2154	>	e = ((TreeBin)ek).first;
2155	>	else {
2156	>	tab = (Node[])ek;
2157	>	continue;           // restarts due to null val
2158	>	}
2159	>	}                           // visit upper slots if present
2160	>	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2161	>	}
2162	>	nextKey = e.key;
2163	>	} while ((nextVal = e.val) == null);// skip deleted or special nodes
2164	>	next = e;
2165		}
2166		}
2167
2168		/* ---------------- Public operations -------------- */
2169
2170		/**
2171	<	* Creates a new, empty map with the specified initial
882	<	* capacity, load factor and concurrency level.
883	<	*
884	<	* @param initialCapacity the initial capacity. The implementation
885	<	* performs internal sizing to accommodate this many elements.
886	<	* @param loadFactor  the load factor threshold, used to control resizing.
887	<	* Resizing may be performed when the average number of elements per
888	<	* bin exceeds this threshold.
889	<	* @param concurrencyLevel the estimated number of concurrently
890	<	* updating threads. The implementation may use this value as
891	<	* a sizing hint.
892	<	* @throws IllegalArgumentException if the initial capacity is
893	<	* negative or the load factor or concurrencyLevel are
894	<	* nonpositive.
2171	>	* Creates a new, empty map with the default initial table size (16),
2172		*/
2173	<	public ConcurrentHashMapV8(int initialCapacity,
897	<	float loadFactor, int concurrencyLevel) {
898	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
899	<	throw new IllegalArgumentException();
900	<	this.initCap = initialCapacity;
901	<	this.loadFactor = loadFactor;
2173	>	public ConcurrentHashMapV8() {
2174		this.counter = new LongAdder();
2175		}
2176
2177		/**
2178	<	* Creates a new, empty map with the specified initial capacity
2179	<	* and load factor and with the default concurrencyLevel (16).
2178	>	* Creates a new, empty map with an initial table size
2179	>	* accommodating the specified number of elements without the need
2180	>	* to dynamically resize.
2181		*
2182		* @param initialCapacity The implementation performs internal
2183		* sizing to accommodate this many elements.
911	–	* @param loadFactor  the load factor threshold, used to control resizing.
912	–	* Resizing may be performed when the average number of elements per
913	–	* bin exceeds this threshold.
2184		* @throws IllegalArgumentException if the initial capacity of
2185	<	* elements is negative or the load factor is nonpositive
916	<	*
917	<	* @since 1.6
2185	>	* elements is negative
2186		*/
2187	<	public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
2188	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
2187	>	public ConcurrentHashMapV8(int initialCapacity) {
2188	>	if (initialCapacity < 0)
2189	>	throw new IllegalArgumentException();
2190	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
2191	>	MAXIMUM_CAPACITY :
2192	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
2193	>	this.counter = new LongAdder();
2194	>	this.sizeCtl = cap;
2195		}
2196
2197		/**
2198	<	* Creates a new, empty map with the specified initial capacity,
925	<	* and with default load factor (0.75) and concurrencyLevel (16).
2198	>	* Creates a new map with the same mappings as the given map.
2199		*
2200	<	* @param initialCapacity the initial capacity. The implementation
928	<	* performs internal sizing to accommodate this many elements.
929	<	* @throws IllegalArgumentException if the initial capacity of
930	<	* elements is negative.
2200	>	* @param m the map
2201		*/
2202	<	public ConcurrentHashMapV8(int initialCapacity) {
2203	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2202	>	public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2203	>	this.counter = new LongAdder();
2204	>	this.sizeCtl = DEFAULT_CAPACITY;
2205	>	internalPutAll(m);
2206		}
2207
2208		/**
2209	<	* Creates a new, empty map with a default initial capacity (16),
2210	<	* load factor (0.75) and concurrencyLevel (16).
2209	>	* Creates a new, empty map with an initial table size based on
2210	>	* the given number of elements ({@code initialCapacity}) and
2211	>	* initial table density ({@code loadFactor}).
2212	>	*
2213	>	* @param initialCapacity the initial capacity. The implementation
2214	>	* performs internal sizing to accommodate this many elements,
2215	>	* given the specified load factor.
2216	>	* @param loadFactor the load factor (table density) for
2217	>	* establishing the initial table size
2218	>	* @throws IllegalArgumentException if the initial capacity of
2219	>	* elements is negative or the load factor is nonpositive
2220	>	*
2221	>	* @since 1.6
2222		*/
2223	<	public ConcurrentHashMapV8() {
2224	<	this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2223	>	public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
2224	>	this(initialCapacity, loadFactor, 1);
2225		}
2226
2227		/**
2228	<	* Creates a new map with the same mappings as the given map.
2229	<	* The map is created with a capacity of 1.5 times the number
2230	<	* of mappings in the given map or 16 (whichever is greater),
2231	<	* and a default load factor (0.75) and concurrencyLevel (16).
2228	>	* Creates a new, empty map with an initial table size based on
2229	>	* the given number of elements ({@code initialCapacity}), table
2230	>	* density ({@code loadFactor}), and number of concurrently
2231	>	* updating threads ({@code concurrencyLevel}).
2232		*
2233	<	* @param m the map
2233	>	* @param initialCapacity the initial capacity. The implementation
2234	>	* performs internal sizing to accommodate this many elements,
2235	>	* given the specified load factor.
2236	>	* @param loadFactor the load factor (table density) for
2237	>	* establishing the initial table size
2238	>	* @param concurrencyLevel the estimated number of concurrently
2239	>	* updating threads. The implementation may use this value as
2240	>	* a sizing hint.
2241	>	* @throws IllegalArgumentException if the initial capacity is
2242	>	* negative or the load factor or concurrencyLevel are
2243	>	* nonpositive
2244		*/
2245	<	public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
2246	<	this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
2247	<	if (m == null)
2248	<	throw new NullPointerException();
2249	<	internalPutAll(m);
2245	>	public ConcurrentHashMapV8(int initialCapacity,
2246	>	float loadFactor, int concurrencyLevel) {
2247	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
2248	>	throw new IllegalArgumentException();
2249	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
2250	>	initialCapacity = concurrencyLevel;   // as estimated threads
2251	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
2252	>	int cap = ((size >= (long)MAXIMUM_CAPACITY) ?
2253	>	MAXIMUM_CAPACITY: tableSizeFor((int)size));
2254	>	this.counter = new LongAdder();
2255	>	this.sizeCtl = cap;
2256		}
2257
2258		/**
2259	<	* Returns {@code true} if this map contains no key-value mappings.
961	<	*
962	<	* @return {@code true} if this map contains no key-value mappings
2259	>	* {@inheritDoc}
2260		*/
2261		public boolean isEmpty() {
2262	<	return counter.sum() == 0L;
2262	>	return counter.sum() <= 0L; // ignore transient negative values
2263		}
2264
2265		/**
2266	<	* Returns the number of key-value mappings in this map.  If the
970	<	* map contains more than {@code Integer.MAX_VALUE} elements, returns
971	<	* {@code Integer.MAX_VALUE}.
972	<	*
973	<	* @return the number of key-value mappings in this map
2266	>	* {@inheritDoc}
2267		*/
2268		public int size() {
2269		long n = counter.sum();
2270	<	return n >= Integer.MAX_VALUE ? Integer.MAX_VALUE : (int)n;
2270	>	return ((n < 0L) ? 0 :
2271	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
2272	>	(int)n);
2273	>	}
2274	>
2275	>	final long longSize() { // accurate version of size needed for views
2276	>	long n = counter.sum();
2277	>	return (n < 0L) ? 0L : n;
2278		}
2279
2280		/**
#	Line 1001 | Line 2301 | public class ConcurrentHashMapV8<K, V>
2301		* @param  key   possible key
2302		* @return {@code true} if and only if the specified object
2303		*         is a key in this table, as determined by the
2304	<	*         {@code equals} method; {@code false} otherwise.
2304	>	*         {@code equals} method; {@code false} otherwise
2305		* @throws NullPointerException if the specified key is null
2306		*/
2307		public boolean containsKey(Object key) {
#	Line 1012 | Line 2312 | public class ConcurrentHashMapV8<K, V>
2312
2313		/**
2314		* Returns {@code true} if this map maps one or more keys to the
2315	<	* specified value. Note: This method requires a full internal
2316	<	* traversal of the hash table, and so is much slower than
1017	<	* method {@code containsKey}.
2315	>	* specified value. Note: This method may require a full traversal
2316	>	* of the map, and is much slower than method {@code containsKey}.
2317		*
2318		* @param value value whose presence in this map is to be tested
2319		* @return {@code true} if this map maps one or more keys to the
#	Line 1024 | Line 2323 | public class ConcurrentHashMapV8<K, V>
2323		public boolean containsValue(Object value) {
2324		if (value == null)
2325		throw new NullPointerException();
2326	<	return new HashIterator().containsVal(value);
2326	>	Object v;
2327	>	InternalIterator it = new InternalIterator(table);
2328	>	while (it.next != null) {
2329	>	if ((v = it.nextVal) == value || value.equals(v))
2330	>	return true;
2331	>	it.advance();
2332	>	}
2333	>	return false;
2334		}
2335
2336		/**
#	Line 1063 | Line 2369 | public class ConcurrentHashMapV8<K, V>
2369		public V put(K key, V value) {
2370		if (key == null || value == null)
2371		throw new NullPointerException();
2372	<	return (V)internalPut(key, value, true);
2372	>	return (V)internalPut(key, value);
2373		}
2374
2375		/**
#	Line 1077 | Line 2383 | public class ConcurrentHashMapV8<K, V>
2383		public V putIfAbsent(K key, V value) {
2384		if (key == null || value == null)
2385		throw new NullPointerException();
2386	<	return (V)internalPut(key, value, false);
2386	>	return (V)internalPutIfAbsent(key, value);
2387		}
2388
2389		/**
#	Line 1088 | Line 2394 | public class ConcurrentHashMapV8<K, V>
2394		* @param m mappings to be stored in this map
2395		*/
2396		public void putAll(Map<? extends K, ? extends V> m) {
1091	–	if (m == null)
1092	–	throw new NullPointerException();
2397		internalPutAll(m);
2398		}
2399
2400		/**
2401		* If the specified key is not already associated with a value,
2402	<	* computes its value using the given mappingFunction, and if
2403	<	* non-null, enters it into the map.  This is equivalent to
2404	<	*
2405	<	* <pre>
2406	<	*   if (map.containsKey(key))
2407	<	*       return map.get(key);
2408	<	*   value = mappingFunction.map(key);
2409	<	*   if (value != null)
2410	<	*      return map.put(key, value);
2411	<	*   else
2412	<	*      return null;
2413	<	* </pre>
2414	<	*
2415	<	* except that the action is performed atomically.  Some attempted
2402	>	* computes its value using the given mappingFunction and
2403	>	* enters it into the map.  This is equivalent to
2404	>	* <pre> {@code
2405	>	* if (map.containsKey(key))
2406	>	*   return map.get(key);
2407	>	* value = mappingFunction.map(key);
2408	>	* map.put(key, value);
2409	>	* return value;}</pre>
2410	>	*
2411	>	* except that the action is performed atomically.  If the
2412	>	* function returns {@code null} (in which case a {@code
2413	>	* NullPointerException} is thrown), or the function itself throws
2414	>	* an (unchecked) exception, the exception is rethrown to its
2415	>	* caller, and no mapping is recorded.  Some attempted update
2416		* operations on this map by other threads may be blocked while
2417	<	* computation is in progress. Because this function is invoked
2418	<	* within atomicity control, the computation should be short and
2419	<	* simple, and must not attempt to update any other mappings of
2420	<	* this Map. The most common usage is to construct a new object
2421	<	* serving as an initial mapped value, or memoized result.
2417	>	* computation is in progress, so the computation should be short
2418	>	* and simple, and must not attempt to update any other mappings
2419	>	* of this Map. The most appropriate usage is to construct a new
2420	>	* object serving as an initial mapped value, or memoized result,
2421	>	* as in:
2422	>	*
2423	>	*  <pre> {@code
2424	>	* map.computeIfAbsent(key, new MappingFunction<K, V>() {
2425	>	*   public V map(K k) { return new Value(f(k)); }});}</pre>
2426		*
2427		* @param key key with which the specified value is to be associated
2428		* @param mappingFunction the function to compute a value
2429		* @return the current (existing or computed) value associated with
2430	<	*         the specified key, or {@code null} if the computation
2431	<	*         returned {@code null}.
2432	<	* @throws NullPointerException if the specified key or mappingFunction
2433	<	*         is null,
2430	>	*         the specified key.
2431	>	* @throws NullPointerException if the specified key, mappingFunction,
2432	>	*         or computed value is null
2433	>	* @throws IllegalStateException if the computation detectably
2434	>	*         attempts a recursive update to this map that would
2435	>	*         otherwise never complete
2436		* @throws RuntimeException or Error if the mappingFunction does so,
2437	<	*         in which case the mapping is left unestablished.
2437	>	*         in which case the mapping is left unestablished
2438		*/
2439	+	@SuppressWarnings("unchecked")
2440		public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
2441		if (key == null || mappingFunction == null)
2442		throw new NullPointerException();
2443	<	return computeVal(key, mappingFunction);
2443	>	return (V)internalComputeIfAbsent(key, mappingFunction);
2444	>	}
2445	>
2446	>	/**
2447	>	* Computes and enters a new mapping value given a key and
2448	>	* its current mapped value (or {@code null} if there is no current
2449	>	* mapping). This is equivalent to
2450	>	*  <pre> {@code
2451	>	*  map.put(key, remappingFunction.remap(key, map.get(key));
2452	>	* }</pre>
2453	>	*
2454	>	* except that the action is performed atomically.  If the
2455	>	* function returns {@code null} (in which case a {@code
2456	>	* NullPointerException} is thrown), or the function itself throws
2457	>	* an (unchecked) exception, the exception is rethrown to its
2458	>	* caller, and current mapping is left unchanged.  Some attempted
2459	>	* update operations on this map by other threads may be blocked
2460	>	* while computation is in progress, so the computation should be
2461	>	* short and simple, and must not attempt to update any other
2462	>	* mappings of this Map. For example, to either create or
2463	>	* append new messages to a value mapping:
2464	>	*
2465	>	* <pre> {@code
2466	>	* Map<Key, String> map = ...;
2467	>	* final String msg = ...;
2468	>	* map.compute(key, new RemappingFunction<Key, String>() {
2469	>	*   public String remap(Key k, String v) {
2470	>	*    return (v == null) ? msg : v + msg;});}}</pre>
2471	>	*
2472	>	* @param key key with which the specified value is to be associated
2473	>	* @param remappingFunction the function to compute a value
2474	>	* @return the new value associated with
2475	>	*         the specified key.
2476	>	* @throws NullPointerException if the specified key or remappingFunction
2477	>	*         or computed value is null
2478	>	* @throws IllegalStateException if the computation detectably
2479	>	*         attempts a recursive update to this map that would
2480	>	*         otherwise never complete
2481	>	* @throws RuntimeException or Error if the remappingFunction does so,
2482	>	*         in which case the mapping is unchanged
2483	>	*/
2484	>	@SuppressWarnings("unchecked")
2485	>	public V compute(K key, RemappingFunction<? super K, V> remappingFunction) {
2486	>	if (key == null || remappingFunction == null)
2487	>	throw new NullPointerException();
2488	>	return (V)internalCompute(key, remappingFunction);
2489		}
2490
2491		/**
#	Line 1145 | Line 2501 | public class ConcurrentHashMapV8<K, V>
2501		public V remove(Object key) {
2502		if (key == null)
2503		throw new NullPointerException();
2504	<	return (V)internalReplace(key, null, null);
2504	>	return (V)internalReplace(key, null, null);
2505		}
2506
2507		/**
#	Line 1169 | Line 2525 | public class ConcurrentHashMapV8<K, V>
2525		public boolean replace(K key, V oldValue, V newValue) {
2526		if (key == null || oldValue == null || newValue == null)
2527		throw new NullPointerException();
2528	<	return internalReplace(key, newValue, oldValue) != null;
2528	>	return internalReplace(key, newValue, oldValue) != null;
2529		}
2530
2531		/**
#	Line 1183 | Line 2539 | public class ConcurrentHashMapV8<K, V>
2539		public V replace(K key, V value) {
2540		if (key == null || value == null)
2541		throw new NullPointerException();
2542	<	return (V)internalReplace(key, value, null);
2542	>	return (V)internalReplace(key, value, null);
2543		}
2544
2545		/**
#	Line 1210 | Line 2566 | public class ConcurrentHashMapV8<K, V>
2566		* reflect any modifications subsequent to construction.
2567		*/
2568		public Set<K> keySet() {
2569	<	Set<K> ks = keySet;
2570	<	return (ks != null) ? ks : (keySet = new KeySet());
2569	>	KeySet<K,V> ks = keySet;
2570	>	return (ks != null) ? ks : (keySet = new KeySet<K,V>(this));
2571		}
2572
2573		/**
#	Line 1231 | Line 2587 | public class ConcurrentHashMapV8<K, V>
2587		* reflect any modifications subsequent to construction.
2588		*/
2589		public Collection<V> values() {
2590	<	Collection<V> vs = values;
2591	<	return (vs != null) ? vs : (values = new Values());
2590	>	Values<K,V> vs = values;
2591	>	return (vs != null) ? vs : (values = new Values<K,V>(this));
2592		}
2593
2594		/**
#	Line 1252 | Line 2608 | public class ConcurrentHashMapV8<K, V>
2608		* reflect any modifications subsequent to construction.
2609		*/
2610		public Set<Map.Entry<K,V>> entrySet() {
2611	<	Set<Map.Entry<K,V>> es = entrySet;
2612	<	return (es != null) ? es : (entrySet = new EntrySet());
2611	>	EntrySet<K,V> es = entrySet;
2612	>	return (es != null) ? es : (entrySet = new EntrySet<K,V>(this));
2613		}
2614
2615		/**
#	Line 1263 | Line 2619 | public class ConcurrentHashMapV8<K, V>
2619		* @see #keySet()
2620		*/
2621		public Enumeration<K> keys() {
2622	<	return new KeyIterator();
2622	>	return new KeyIterator<K,V>(this);
2623		}
2624
2625		/**
#	Line 1273 | Line 2629 | public class ConcurrentHashMapV8<K, V>
2629		* @see #values()
2630		*/
2631		public Enumeration<V> elements() {
2632	<	return new ValueIterator();
2632	>	return new ValueIterator<K,V>(this);
2633		}
2634
2635		/**
2636	<	* {@inheritDoc}
2636	>	* Returns the hash code value for this {@link Map}, i.e.,
2637	>	* the sum of, for each key-value pair in the map,
2638	>	* {@code key.hashCode() ^ value.hashCode()}.
2639	>	*
2640	>	* @return the hash code value for this map
2641		*/
2642		public int hashCode() {
2643	<	return new HashIterator().mapHashCode();
2643	>	int h = 0;
2644	>	InternalIterator it = new InternalIterator(table);
2645	>	while (it.next != null) {
2646	>	h += it.nextKey.hashCode() ^ it.nextVal.hashCode();
2647	>	it.advance();
2648	>	}
2649	>	return h;
2650		}
2651
2652		/**
2653	<	* {@inheritDoc}
2653	>	* Returns a string representation of this map.  The string
2654	>	* representation consists of a list of key-value mappings (in no
2655	>	* particular order) enclosed in braces ("{@code {}}").  Adjacent
2656	>	* mappings are separated by the characters {@code ", "} (comma
2657	>	* and space).  Each key-value mapping is rendered as the key
2658	>	* followed by an equals sign ("{@code =}") followed by the
2659	>	* associated value.
2660	>	*
2661	>	* @return a string representation of this map
2662		*/
2663		public String toString() {
2664	<	return new HashIterator().mapToString();
2664	>	InternalIterator it = new InternalIterator(table);
2665	>	StringBuilder sb = new StringBuilder();
2666	>	sb.append('{');
2667	>	if (it.next != null) {
2668	>	for (;;) {
2669	>	Object k = it.nextKey, v = it.nextVal;
2670	>	sb.append(k == this ? "(this Map)" : k);
2671	>	sb.append('=');
2672	>	sb.append(v == this ? "(this Map)" : v);
2673	>	it.advance();
2674	>	if (it.next == null)
2675	>	break;
2676	>	sb.append(',').append(' ');
2677	>	}
2678	>	}
2679	>	return sb.append('}').toString();
2680		}
2681
2682		/**
2683	<	* {@inheritDoc}
2683	>	* Compares the specified object with this map for equality.
2684	>	* Returns {@code true} if the given object is a map with the same
2685	>	* mappings as this map.  This operation may return misleading
2686	>	* results if either map is concurrently modified during execution
2687	>	* of this method.
2688	>	*
2689	>	* @param o object to be compared for equality with this map
2690	>	* @return {@code true} if the specified object is equal to this map
2691		*/
2692		public boolean equals(Object o) {
2693	<	if (o == this)
2694	<	return true;
2695	<	if (!(o instanceof Map))
2696	<	return false;
2697	<	Map<?,?> m = (Map<?,?>) o;
2698	<	try {
2699	<	for (Map.Entry<K,V> e : this.entrySet())
2700	<	if (! e.getValue().equals(m.get(e.getKey())))
2693	>	if (o != this) {
2694	>	if (!(o instanceof Map))
2695	>	return false;
2696	>	Map<?,?> m = (Map<?,?>) o;
2697	>	InternalIterator it = new InternalIterator(table);
2698	>	while (it.next != null) {
2699	>	Object val = it.nextVal;
2700	>	Object v = m.get(it.nextKey);
2701	>	if (v == null || (v != val && !v.equals(val)))
2702		return false;
2703	+	it.advance();
2704	+	}
2705		for (Map.Entry<?,?> e : m.entrySet()) {
2706	<	Object k = e.getKey();
2707	<	Object v = e.getValue();
2708	<	if (k == null || v == null || !v.equals(get(k)))
2706	>	Object mk, mv, v;
2707	>	if ((mk = e.getKey()) == null ||
2708	>	(mv = e.getValue()) == null ||
2709	>	(v = internalGet(mk)) == null ||
2710	>	(mv != v && !mv.equals(v)))
2711		return false;
2712		}
1312	–	return true;
1313	–	} catch (ClassCastException unused) {
1314	–	return false;
1315	–	} catch (NullPointerException unused) {
1316	–	return false;
2713		}
2714	+	return true;
2715		}
2716
2717	+	/* ----------------Iterators -------------- */
2718	+
2719		/**
2720	<	* Custom Entry class used by EntryIterator.next(), that relays
2721	<	* setValue changes to the underlying map.
2720	>	* Base class for key, value, and entry iterators.  Adds a map
2721	>	* reference to InternalIterator to support Iterator.remove.
2722		*/
2723	<	final class WriteThroughEntry extends AbstractMap.SimpleEntry<K,V> {
2723	>	static abstract class ViewIterator<K,V> extends InternalIterator {
2724	>	final ConcurrentHashMapV8<K, V> map;
2725	>	ViewIterator(ConcurrentHashMapV8<K, V> map) {
2726	>	super(map.table);
2727	>	this.map = map;
2728	>	}
2729	>
2730	>	public final void remove() {
2731	>	if (last == null)
2732	>	throw new IllegalStateException();
2733	>	map.remove(last.key);
2734	>	last = null;
2735	>	}
2736	>
2737	>	public final boolean hasNext()         { return next != null; }
2738	>	public final boolean hasMoreElements() { return next != null; }
2739	>	}
2740	>
2741	>	static final class KeyIterator<K,V> extends ViewIterator<K,V>
2742	>	implements Iterator<K>, Enumeration<K> {
2743	>	KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2744	>
2745	>	@SuppressWarnings("unchecked")
2746	>	public final K next() {
2747	>	if (next == null)
2748	>	throw new NoSuchElementException();
2749	>	Object k = nextKey;
2750	>	advance();
2751	>	return (K)k;
2752	>	}
2753	>
2754	>	public final K nextElement() { return next(); }
2755	>	}
2756	>
2757	>	static final class ValueIterator<K,V> extends ViewIterator<K,V>
2758	>	implements Iterator<V>, Enumeration<V> {
2759	>	ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2760	>
2761		@SuppressWarnings("unchecked")
2762	<	WriteThroughEntry(Object k, Object v) {
2763	<	super((K)k, (V)v);
2762	>	public final V next() {
2763	>	if (next == null)
2764	>	throw new NoSuchElementException();
2765	>	Object v = nextVal;
2766	>	advance();
2767	>	return (V)v;
2768	>	}
2769	>
2770	>	public final V nextElement() { return next(); }
2771	>	}
2772	>
2773	>	static final class EntryIterator<K,V> extends ViewIterator<K,V>
2774	>	implements Iterator<Map.Entry<K,V>> {
2775	>	EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2776	>
2777	>	@SuppressWarnings("unchecked")
2778	>	public final Map.Entry<K,V> next() {
2779	>	if (next == null)
2780	>	throw new NoSuchElementException();
2781	>	Object k = nextKey;
2782	>	Object v = nextVal;
2783	>	advance();
2784	>	return new WriteThroughEntry<K,V>((K)k, (V)v, map);
2785	>	}
2786	>	}
2787	>
2788	>	static final class SnapshotEntryIterator<K,V> extends ViewIterator<K,V>
2789	>	implements Iterator<Map.Entry<K,V>> {
2790	>	SnapshotEntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2791	>
2792	>	@SuppressWarnings("unchecked")
2793	>	public final Map.Entry<K,V> next() {
2794	>	if (next == null)
2795	>	throw new NoSuchElementException();
2796	>	Object k = nextKey;
2797	>	Object v = nextVal;
2798	>	advance();
2799	>	return new SnapshotEntry<K,V>((K)k, (V)v);
2800	>	}
2801	>	}
2802	>
2803	>	/**
2804	>	* Base of writeThrough and Snapshot entry classes
2805	>	*/
2806	>	static abstract class MapEntry<K,V> implements Map.Entry<K, V> {
2807	>	final K key; // non-null
2808	>	V val;       // non-null
2809	>	MapEntry(K key, V val)        { this.key = key; this.val = val; }
2810	>	public final K getKey()       { return key; }
2811	>	public final V getValue()     { return val; }
2812	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
2813	>	public final String toString(){ return key + "=" + val; }
2814	>
2815	>	public final boolean equals(Object o) {
2816	>	Object k, v; Map.Entry<?,?> e;
2817	>	return ((o instanceof Map.Entry) &&
2818	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
2819	>	(v = e.getValue()) != null &&
2820	>	(k == key || k.equals(key)) &&
2821	>	(v == val || v.equals(val)));
2822	>	}
2823	>
2824	>	public abstract V setValue(V value);
2825	>	}
2826	>
2827	>	/**
2828	>	* Entry used by EntryIterator.next(), that relays setValue
2829	>	* changes to the underlying map.
2830	>	*/
2831	>	static final class WriteThroughEntry<K,V> extends MapEntry<K,V>
2832	>	implements Map.Entry<K, V> {
2833	>	final ConcurrentHashMapV8<K, V> map;
2834	>	WriteThroughEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
2835	>	super(key, val);
2836	>	this.map = map;
2837		}
2838
2839		/**
#	Line 1336 | Line 2845 | public class ConcurrentHashMapV8<K, V>
2845		* removed in which case the put will re-establish). We do not
2846		* and cannot guarantee more.
2847		*/
2848	<	public V setValue(V value) {
2848	>	public final V setValue(V value) {
2849		if (value == null) throw new NullPointerException();
2850	<	V v = super.setValue(value);
2851	<	ConcurrentHashMapV8.this.put(getKey(), value);
2850	>	V v = val;
2851	>	val = value;
2852	>	map.put(key, value);
2853		return v;
2854		}
2855		}
2856
2857	<	final class KeyIterator extends HashIterator
2858	<	implements Iterator<K>, Enumeration<K> {
2859	<	@SuppressWarnings("unchecked")
2860	<	public final K next()        { return (K)super.nextKey(); }
2861	<	@SuppressWarnings("unchecked")
2862	<	public final K nextElement() { return (K)super.nextKey(); }
2857	>	/**
2858	>	* Internal version of entry, that doesn't write though changes
2859	>	*/
2860	>	static final class SnapshotEntry<K,V> extends MapEntry<K,V>
2861	>	implements Map.Entry<K, V> {
2862	>	SnapshotEntry(K key, V val) { super(key, val); }
2863	>	public final V setValue(V value) { // only locally update
2864	>	if (value == null) throw new NullPointerException();
2865	>	V v = val;
2866	>	val = value;
2867	>	return v;
2868	>	}
2869		}
2870
2871	<	final class ValueIterator extends HashIterator
2872	<	implements Iterator<V>, Enumeration<V> {
2873	<	@SuppressWarnings("unchecked")
2874	<	public final V next()        { return (V)super.nextValue(); }
2871	>	/* ----------------Views -------------- */
2872	>
2873	>	/**
2874	>	* Base class for views. This is done mainly to allow adding
2875	>	* customized parallel traversals (not yet implemented.)
2876	>	*/
2877	>	static abstract class MapView<K, V> {
2878	>	final ConcurrentHashMapV8<K, V> map;
2879	>	MapView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
2880	>	public final int size()                 { return map.size(); }
2881	>	public final boolean isEmpty()          { return map.isEmpty(); }
2882	>	public final void clear()               { map.clear(); }
2883	>
2884	>	// implementations below rely on concrete classes supplying these
2885	>	abstract Iterator<?> iter();
2886	>	abstract public boolean contains(Object o);
2887	>	abstract public boolean remove(Object o);
2888	>
2889	>	private static final String oomeMsg = "Required array size too large";
2890	>
2891	>	public final Object[] toArray() {
2892	>	long sz = map.longSize();
2893	>	if (sz > (long)(MAX_ARRAY_SIZE))
2894	>	throw new OutOfMemoryError(oomeMsg);
2895	>	int n = (int)sz;
2896	>	Object[] r = new Object[n];
2897	>	int i = 0;
2898	>	Iterator<?> it = iter();
2899	>	while (it.hasNext()) {
2900	>	if (i == n) {
2901	>	if (n >= MAX_ARRAY_SIZE)
2902	>	throw new OutOfMemoryError(oomeMsg);
2903	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
2904	>	n = MAX_ARRAY_SIZE;
2905	>	else
2906	>	n += (n >>> 1) + 1;
2907	>	r = Arrays.copyOf(r, n);
2908	>	}
2909	>	r[i++] = it.next();
2910	>	}
2911	>	return (i == n) ? r : Arrays.copyOf(r, i);
2912	>	}
2913	>
2914		@SuppressWarnings("unchecked")
2915	<	public final V nextElement() { return (V)super.nextValue(); }
2916	<	}
2915	>	public final <T> T[] toArray(T[] a) {
2916	>	long sz = map.longSize();
2917	>	if (sz > (long)(MAX_ARRAY_SIZE))
2918	>	throw new OutOfMemoryError(oomeMsg);
2919	>	int m = (int)sz;
2920	>	T[] r = (a.length >= m) ? a :
2921	>	(T[])java.lang.reflect.Array
2922	>	.newInstance(a.getClass().getComponentType(), m);
2923	>	int n = r.length;
2924	>	int i = 0;
2925	>	Iterator<?> it = iter();
2926	>	while (it.hasNext()) {
2927	>	if (i == n) {
2928	>	if (n >= MAX_ARRAY_SIZE)
2929	>	throw new OutOfMemoryError(oomeMsg);
2930	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
2931	>	n = MAX_ARRAY_SIZE;
2932	>	else
2933	>	n += (n >>> 1) + 1;
2934	>	r = Arrays.copyOf(r, n);
2935	>	}
2936	>	r[i++] = (T)it.next();
2937	>	}
2938	>	if (a == r && i < n) {
2939	>	r[i] = null; // null-terminate
2940	>	return r;
2941	>	}
2942	>	return (i == n) ? r : Arrays.copyOf(r, i);
2943	>	}
2944
2945	<	final class EntryIterator extends HashIterator
2946	<	implements Iterator<Entry<K,V>> {
2947	<	public final Map.Entry<K,V> next() { return super.nextEntry(); }
2948	<	}
2945	>	public final int hashCode() {
2946	>	int h = 0;
2947	>	for (Iterator<?> it = iter(); it.hasNext();)
2948	>	h += it.next().hashCode();
2949	>	return h;
2950	>	}
2951
2952	<	final class KeySet extends AbstractSet<K> {
2953	<	public int size() {
2954	<	return ConcurrentHashMapV8.this.size();
2952	>	public final String toString() {
2953	>	StringBuilder sb = new StringBuilder();
2954	>	sb.append('[');
2955	>	Iterator<?> it = iter();
2956	>	if (it.hasNext()) {
2957	>	for (;;) {
2958	>	Object e = it.next();
2959	>	sb.append(e == this ? "(this Collection)" : e);
2960	>	if (!it.hasNext())
2961	>	break;
2962	>	sb.append(',').append(' ');
2963	>	}
2964	>	}
2965	>	return sb.append(']').toString();
2966		}
2967	<	public boolean isEmpty() {
2968	<	return ConcurrentHashMapV8.this.isEmpty();
2967	>
2968	>	public final boolean containsAll(Collection<?> c) {
2969	>	if (c != this) {
2970	>	for (Iterator<?> it = c.iterator(); it.hasNext();) {
2971	>	Object e = it.next();
2972	>	if (e == null || !contains(e))
2973	>	return false;
2974	>	}
2975	>	}
2976	>	return true;
2977		}
2978	<	public void clear() {
2979	<	ConcurrentHashMapV8.this.clear();
2978	>
2979	>	public final boolean removeAll(Collection<?> c) {
2980	>	boolean modified = false;
2981	>	for (Iterator<?> it = iter(); it.hasNext();) {
2982	>	if (c.contains(it.next())) {
2983	>	it.remove();
2984	>	modified = true;
2985	>	}
2986	>	}
2987	>	return modified;
2988		}
2989	<	public Iterator<K> iterator() {
2990	<	return new KeyIterator();
2989	>
2990	>	public final boolean retainAll(Collection<?> c) {
2991	>	boolean modified = false;
2992	>	for (Iterator<?> it = iter(); it.hasNext();) {
2993	>	if (!c.contains(it.next())) {
2994	>	it.remove();
2995	>	modified = true;
2996	>	}
2997	>	}
2998	>	return modified;
2999		}
3000	<	public boolean contains(Object o) {
3001	<	return ConcurrentHashMapV8.this.containsKey(o);
3000	>
3001	>	}
3002	>
3003	>	static final class KeySet<K,V> extends MapView<K,V> implements Set<K> {
3004	>	KeySet(ConcurrentHashMapV8<K, V> map)   { super(map); }
3005	>	public final boolean contains(Object o) { return map.containsKey(o); }
3006	>	public final boolean remove(Object o)   { return map.remove(o) != null; }
3007	>
3008	>	public final Iterator<K> iterator() {
3009	>	return new KeyIterator<K,V>(map);
3010		}
3011	<	public boolean remove(Object o) {
3012	<	return ConcurrentHashMapV8.this.remove(o) != null;
3011	>	final Iterator<?> iter() {
3012	>	return new KeyIterator<K,V>(map);
3013	>	}
3014	>	public final boolean add(K e) {
3015	>	throw new UnsupportedOperationException();
3016	>	}
3017	>	public final boolean addAll(Collection<? extends K> c) {
3018	>	throw new UnsupportedOperationException();
3019	>	}
3020	>	public boolean equals(Object o) {
3021	>	Set<?> c;
3022	>	return ((o instanceof Set) &&
3023	>	((c = (Set<?>)o) == this ||
3024	>	(containsAll(c) && c.containsAll(this))));
3025		}
3026		}
3027
3028	<	final class Values extends AbstractCollection<V> {
3029	<	public int size() {
3030	<	return ConcurrentHashMapV8.this.size();
3028	>	static final class Values<K,V> extends MapView<K,V>
3029	>	implements Collection<V> {
3030	>	Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
3031	>	public final boolean contains(Object o) { return map.containsValue(o); }
3032	>
3033	>	public final boolean remove(Object o) {
3034	>	if (o != null) {
3035	>	Iterator<V> it = new ValueIterator<K,V>(map);
3036	>	while (it.hasNext()) {
3037	>	if (o.equals(it.next())) {
3038	>	it.remove();
3039	>	return true;
3040	>	}
3041	>	}
3042	>	}
3043	>	return false;
3044		}
3045	<	public boolean isEmpty() {
3046	<	return ConcurrentHashMapV8.this.isEmpty();
3045	>	public final Iterator<V> iterator() {
3046	>	return new ValueIterator<K,V>(map);
3047		}
3048	<	public void clear() {
3049	<	ConcurrentHashMapV8.this.clear();
3048	>	final Iterator<?> iter() {
3049	>	return new ValueIterator<K,V>(map);
3050		}
3051	<	public Iterator<V> iterator() {
3052	<	return new ValueIterator();
3051	>	public final boolean add(V e) {
3052	>	throw new UnsupportedOperationException();
3053		}
3054	<	public boolean contains(Object o) {
3055	<	return ConcurrentHashMapV8.this.containsValue(o);
3054	>	public final boolean addAll(Collection<? extends V> c) {
3055	>	throw new UnsupportedOperationException();
3056		}
3057		}
3058
3059	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
3060	<	public int size() {
3061	<	return ConcurrentHashMapV8.this.size();
3059	>	static final class EntrySet<K,V> extends MapView<K,V>
3060	>	implements Set<Map.Entry<K,V>> {
3061	>	EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
3062	>
3063	>	public final boolean contains(Object o) {
3064	>	Object k, v, r; Map.Entry<?,?> e;
3065	>	return ((o instanceof Map.Entry) &&
3066	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3067	>	(r = map.get(k)) != null &&
3068	>	(v = e.getValue()) != null &&
3069	>	(v == r || v.equals(r)));
3070		}
3071	<	public boolean isEmpty() {
3072	<	return ConcurrentHashMapV8.this.isEmpty();
3071	>
3072	>	public final boolean remove(Object o) {
3073	>	Object k, v; Map.Entry<?,?> e;
3074	>	return ((o instanceof Map.Entry) &&
3075	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
3076	>	(v = e.getValue()) != null &&
3077	>	map.remove(k, v));
3078		}
3079	<	public void clear() {
3080	<	ConcurrentHashMapV8.this.clear();
3079	>
3080	>	public final Iterator<Map.Entry<K,V>> iterator() {
3081	>	return new EntryIterator<K,V>(map);
3082		}
3083	<	public Iterator<Map.Entry<K,V>> iterator() {
3084	<	return new EntryIterator();
3083	>	final Iterator<?> iter() {
3084	>	return new SnapshotEntryIterator<K,V>(map);
3085		}
3086	<	public boolean contains(Object o) {
3087	<	if (!(o instanceof Map.Entry))
1422	<	return false;
1423	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
1424	<	V v = ConcurrentHashMapV8.this.get(e.getKey());
1425	<	return v != null && v.equals(e.getValue());
3086	>	public final boolean add(Entry<K,V> e) {
3087	>	throw new UnsupportedOperationException();
3088		}
3089	<	public boolean remove(Object o) {
3090	<	if (!(o instanceof Map.Entry))
3091	<	return false;
3092	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
3093	<	return ConcurrentHashMapV8.this.remove(e.getKey(), e.getValue());
3089	>	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
3090	>	throw new UnsupportedOperationException();
3091	>	}
3092	>	public boolean equals(Object o) {
3093	>	Set<?> c;
3094	>	return ((o instanceof Set) &&
3095	>	((c = (Set<?>)o) == this ||
3096	>	(containsAll(c) && c.containsAll(this))));
3097		}
3098		}
3099
3100		/* ---------------- Serialization Support -------------- */
3101
3102		/**
3103	<	* Helper class used in previous version, declared for the sake of
3104	<	* serialization compatibility
3103	>	* Stripped-down version of helper class used in previous version,
3104	>	* declared for the sake of serialization compatibility
3105		*/
3106	<	static class Segment<K,V> extends java.util.concurrent.locks.ReentrantLock
1442	<	implements Serializable {
3106	>	static class Segment<K,V> implements Serializable {
3107		private static final long serialVersionUID = 2249069246763182397L;
3108		final float loadFactor;
3109		Segment(float lf) { this.loadFactor = lf; }
#	Line 1461 | Line 3125 | public class ConcurrentHashMapV8<K, V>
3125		segments = (Segment<K,V>[])
3126		new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
3127		for (int i = 0; i < segments.length; ++i)
3128	<	segments[i] = new Segment<K,V>(loadFactor);
3128	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
3129		}
3130		s.defaultWriteObject();
3131	<	new HashIterator().writeEntries(s);
3131	>	InternalIterator it = new InternalIterator(table);
3132	>	while (it.next != null) {
3133	>	s.writeObject(it.nextKey);
3134	>	s.writeObject(it.nextVal);
3135	>	it.advance();
3136	>	}
3137		s.writeObject(null);
3138		s.writeObject(null);
3139		segments = null; // throw away
3140		}
3141
3142		/**
3143	<	* Reconstitutes the  instance from a
1475	<	* stream (i.e., deserializes it).
3143	>	* Reconstitutes the instance from a stream (that is, deserializes it).
3144		* @param s the stream
3145		*/
3146		@SuppressWarnings("unchecked")
3147		private void readObject(java.io.ObjectInputStream s)
3148		throws java.io.IOException, ClassNotFoundException {
3149		s.defaultReadObject();
1482	–	// find load factor in a segment, if one exists
1483	–	if (segments != null && segments.length != 0)
1484	–	this.loadFactor = segments[0].loadFactor;
1485	–	else
1486	–	this.loadFactor = DEFAULT_LOAD_FACTOR;
1487	–	this.initCap = DEFAULT_CAPACITY;
1488	–	LongAdder ct = new LongAdder(); // force final field write
1489	–	UNSAFE.putObjectVolatile(this, counterOffset, ct);
3150		this.segments = null; // unneeded
3151	+	// initialize transient final field
3152	+	UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
3153
3154	<	// Read the keys and values, and put the mappings in the table
3154	>	// Create all nodes, then place in table once size is known
3155	>	long size = 0L;
3156	>	Node p = null;
3157		for (;;) {
3158	<	K key = (K) s.readObject();
3159	<	V value = (V) s.readObject();
3160	<	if (key == null)
3158	>	K k = (K) s.readObject();
3159	>	V v = (V) s.readObject();
3160	>	if (k != null && v != null) {
3161	>	int h = spread(k.hashCode());
3162	>	p = new Node(h, k, v, p);
3163	>	++size;
3164	>	}
3165	>	else
3166		break;
3167	<	put(key, value);
3167	>	}
3168	>	if (p != null) {
3169	>	boolean init = false;
3170	>	int n;
3171	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
3172	>	n = MAXIMUM_CAPACITY;
3173	>	else {
3174	>	int sz = (int)size;
3175	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
3176	>	}
3177	>	int sc = sizeCtl;
3178	>	boolean collide = false;
3179	>	if (n > sc &&
3180	>	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
3181	>	try {
3182	>	if (table == null) {
3183	>	init = true;
3184	>	Node[] tab = new Node[n];
3185	>	int mask = n - 1;
3186	>	while (p != null) {
3187	>	int j = p.hash & mask;
3188	>	Node next = p.next;
3189	>	Node q = p.next = tabAt(tab, j);
3190	>	setTabAt(tab, j, p);
3191	>	if (!collide && q != null && q.hash == p.hash)
3192	>	collide = true;
3193	>	p = next;
3194	>	}
3195	>	table = tab;
3196	>	counter.add(size);
3197	>	sc = n - (n >>> 2);
3198	>	}
3199	>	} finally {
3200	>	sizeCtl = sc;
3201	>	}
3202	>	if (collide) { // rescan and convert to TreeBins
3203	>	Node[] tab = table;
3204	>	for (int i = 0; i < tab.length; ++i) {
3205	>	int c = 0;
3206	>	for (Node e = tabAt(tab, i); e != null; e = e.next) {
3207	>	if (++c > TREE_THRESHOLD &&
3208	>	(e.key instanceof Comparable)) {
3209	>	replaceWithTreeBin(tab, i, e.key);
3210	>	break;
3211	>	}
3212	>	}
3213	>	}
3214	>	}
3215	>	}
3216	>	if (!init) { // Can only happen if unsafely published.
3217	>	while (p != null) {
3218	>	internalPut(p.key, p.val);
3219	>	p = p.next;
3220	>	}
3221	>	}
3222	>
3223		}
3224		}
3225
3226		// Unsafe mechanics
3227		private static final sun.misc.Unsafe UNSAFE;
3228		private static final long counterOffset;
3229	<	private static final long resizingOffset;
3229	>	private static final long sizeCtlOffset;
3230		private static final long ABASE;
3231		private static final int ASHIFT;
3232
#	Line 1513 | Line 3237 | public class ConcurrentHashMapV8<K, V>
3237		Class<?> k = ConcurrentHashMapV8.class;
3238		counterOffset = UNSAFE.objectFieldOffset
3239		(k.getDeclaredField("counter"));
3240	<	resizingOffset = UNSAFE.objectFieldOffset
3241	<	(k.getDeclaredField("resizing"));
3240	>	sizeCtlOffset = UNSAFE.objectFieldOffset
3241	>	(k.getDeclaredField("sizeCtl"));
3242		Class<?> sc = Node[].class;
3243		ABASE = UNSAFE.arrayBaseOffset(sc);
3244		ss = UNSAFE.arrayIndexScale(sc);

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