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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.6 by jsr166, Tue Aug 30 13:30:35 2011 UTC vs.
Revision 1.26 by jsr166, Wed Sep 21 11:42:08 2011 UTC

#	Line 6 | Line 6
6
7		package jsr166e;
8		import jsr166e.LongAdder;
9	+	import java.util.Arrays;
10		import java.util.Map;
11		import java.util.Set;
12		import java.util.Collection;
#	Line 19 | Line 20 | import java.util.Enumeration;
20		import java.util.ConcurrentModificationException;
21		import java.util.NoSuchElementException;
22		import java.util.concurrent.ConcurrentMap;
23	+	import java.util.concurrent.locks.LockSupport;
24		import java.io.Serializable;
25
26		/**
#	Line 49 | Line 51 | import java.io.Serializable;
51		* are typically useful only when a map is not undergoing concurrent
52		* updates in other threads.  Otherwise the results of these methods
53		* reflect transient states that may be adequate for monitoring
54	<	* purposes, but not for program control.
54	>	* or estimation purposes, but not for program control.
55		*
56	<	* <p> Resizing this or any other kind of hash table is a relatively
57	<	* slow operation, so, when possible, it is a good idea to provide
58	<	* estimates of expected table sizes in constructors. Also, for
59	<	* compatability with previous versions of this class, constructors
60	<	* may optionally specify an expected {@code concurrencyLevel} as an
61	<	* additional hint for internal sizing.
56	>	* <p> The table is dynamically expanded when there are too many
57	>	* collisions (i.e., keys that have distinct hash codes but fall into
58	>	* the same slot modulo the table size), with the expected average
59	>	* effect of maintaining roughly two bins per mapping (corresponding
60	>	* to a 0.75 load factor threshold for resizing). There may be much
61	>	* variance around this average as mappings are added and removed, but
62	>	* overall, this maintains a commonly accepted time/space tradeoff for
63	>	* hash tables.  However, resizing this or any other kind of hash
64	>	* table may be a relatively slow operation. When possible, it is a
65	>	* good idea to provide a size estimate as an optional {@code
66	>	* initialCapacity} constructor argument. An additional optional
67	>	* {@code loadFactor} constructor argument provides a further means of
68	>	* customizing initial table capacity by specifying the table density
69	>	* to be used in calculating the amount of space to allocate for the
70	>	* given number of elements.  Also, for compatibility with previous
71	>	* versions of this class, constructors may optionally specify an
72	>	* expected {@code concurrencyLevel} as an additional hint for
73	>	* internal sizing.  Note that using many keys with exactly the same
74	>	* {@code hashCode{}} is a sure way to slow down performance of any
75	>	* hash table.
76		*
77		* <p>This class and its views and iterators implement all of the
78		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
#	Line 83 | Line 99 | public class ConcurrentHashMapV8<K, V>
99
100		/**
101		* A function computing a mapping from the given key to a value,
102	<	*  or <code>null</code> if there is no mapping. This is a
103	<	* place-holder for an upcoming JDK8 interface.
102	>	* or {@code null} if there is no mapping. This is a place-holder
103	>	* for an upcoming JDK8 interface.
104		*/
105		public static interface MappingFunction<K, V> {
106		/**
#	Line 108 | Line 124 | public class ConcurrentHashMapV8<K, V>
124		* The primary design goal of this hash table is to maintain
125		* concurrent readability (typically method get(), but also
126		* iterators and related methods) while minimizing update
127	<	* contention.
127	>	* contention. Secondary goals are to keep space consumption about
128	>	* the same or better than java.util.HashMap, and to support high
129	>	* initial insertion rates on an empty table by many threads.
130		*
131		* Each key-value mapping is held in a Node.  Because Node fields
132		* can contain special values, they are defined using plain Object
133		* types. Similarly in turn, all internal methods that use them
134	<	* work off Object types. All public generic-typed methods relay
135	<	* in/out of these internal methods, supplying casts as needed.
134	>	* work off Object types. And similarly, so do the internal
135	>	* methods of auxiliary iterator and view classes.  All public
136	>	* generic typed methods relay in/out of these internal methods,
137	>	* supplying null-checks and casts as needed.
138		*
139		* The table is lazily initialized to a power-of-two size upon the
140	<	* first insertion.  Each bin in the table contains a (typically
141	<	* short) list of Nodes.  Table accesses require volatile/atomic
142	<	* reads, writes, and CASes.  Because there is no other way to
143	<	* arrange this without adding further indirections, we use
144	<	* intrinsics (sun.misc.Unsafe) operations.  The lists of nodes
145	<	* within bins are always accurately traversable under volatile
146	<	* reads, so long as lookups check hash code and non-nullness of
147	<	* key and value before checking key equality. (All valid hash
148	<	* codes are nonnegative. Negative values are reserved for special
149	<	* forwarding nodes; see below.)
150	<	*
151	<	* A bin may be locked during update (insert, delete, and replace)
152	<	* operations.  We do not want to waste the space required to
153	<	* associate a distinct lock object with each bin, so instead use
154	<	* the first node of a bin list itself as a lock, using builtin
155	<	* "synchronized" locks. These save space and we can live with
156	<	* only plain block-structured lock/unlock operations. Using the
157	<	* first node of a list as a lock does not by itself suffice
158	<	* though: When a node is locked, any update must first validate
159	<	* that it is still the first node, and retry if not. (Because new
160	<	* nodes are always appended to lists, once a node is first in a
161	<	* bin, it remains first until deleted or the bin becomes
162	<	* invalidated.)  However, update operations can and usually do
163	<	* still traverse the bin until the point of update, which helps
164	<	* reduce cache misses on retries.  This is a converse of sorts to
165	<	* the lazy locking technique described by Herlihy & Shavit. If
166	<	* there is no existing node during a put operation, then one can
167	<	* be CAS'ed in (without need for lock except in computeIfAbsent);
168	<	* the CAS serves as validation. This is on average the most
169	<	* common case for put operations -- under random hash codes, the
170	<	* distribution of nodes in bins follows a Poisson distribution
171	<	* (see http://en.wikipedia.org/wiki/Poisson_distribution) with a
172	<	* parameter of 0.5 on average under the default loadFactor of
173	<	* 0.75.  The expected number of locks covering different elements
174	<	* (i.e., bins with 2 or more nodes) is approximately 10% at
175	<	* steady state under default settings.  Lock contention
176	<	* probability for two threads accessing arbitrary distinct
177	<	* elements is, roughly, 1 / (8 * #elements).
178	<	*
179	<	* The table is resized when occupancy exceeds a threshold.  Only
180	<	* a single thread performs the resize (using field "resizing", to
181	<	* arrange exclusion), but the table otherwise remains usable for
182	<	* both reads and updates. Resizing proceeds by transferring bins,
183	<	* one by one, from the table to the next table.  Upon transfer,
184	<	* the old table bin contains only a special forwarding node (with
185	<	* negative hash code ("MOVED")) that contains the next table as
140	>	* first insertion.  Each bin in the table contains a list of
141	>	* Nodes (most often, zero or one Node).  Table accesses require
142	>	* volatile/atomic reads, writes, and CASes.  Because there is no
143	>	* other way to arrange this without adding further indirections,
144	>	* we use intrinsics (sun.misc.Unsafe) operations.  The lists of
145	>	* nodes within bins are always accurately traversable under
146	>	* volatile reads, so long as lookups check hash code and
147	>	* non-nullness of value before checking key equality.
148	>	*
149	>	* We use the top two bits of Node hash fields for control
150	>	* purposes -- they are available anyway because of addressing
151	>	* constraints.  As explained further below, these top bits are
152	>	* usd as follows:
153	>	*  00 - Normal
154	>	*  01 - Locked
155	>	*  11 - Locked and may have a thread waiting for lock
156	>	*  10 - Node is a forwarding node
157	>	*
158	>	* The lower 30 bits of each Node's hash field contain a
159	>	* transformation (for better randomization -- method "spread") of
160	>	* the key's hash code, except for forwarding nodes, for which the
161	>	* lower bits are zero (and so always have hash field == "MOVED").
162	>	*
163	>	* Insertion (via put or putIfAbsent) of the first node in an
164	>	* empty bin is performed by just CASing it to the bin.  This is
165	>	* by far the most common case for put operations.  Other update
166	>	* operations (insert, delete, and replace) require locks.  We do
167	>	* not want to waste the space required to associate a distinct
168	>	* lock object with each bin, so instead use the first node of a
169	>	* bin list itself as a lock. Blocking support for these locks
170	>	* relies on the builtin "synchronized" monitors.  However, we
171	>	* also need a tryLock construction, so we overlay these by using
172	>	* bits of the Node hash field for lock control (see above), and
173	>	* so normally use builtin monitors only for blocking and
174	>	* signalling using wait/notifyAll constructions. See
175	>	* Node.tryAwaitLock.
176	>	*
177	>	* Using the first node of a list as a lock does not by itself
178	>	* suffice though: When a node is locked, any update must first
179	>	* validate that it is still the first node after locking it, and
180	>	* retry if not. Because new nodes are always appended to lists,
181	>	* once a node is first in a bin, it remains first until deleted
182	>	* or the bin becomes invalidated.  However, operations that only
183	>	* conditionally update may inspect nodes until the point of
184	>	* update. This is a converse of sorts to the lazy locking
185	>	* technique described by Herlihy & Shavit.
186	>	*
187	>	* The main disadvantage of per-bin locks is that other update
188	>	* operations on other nodes in a bin list protected by the same
189	>	* lock can stall, for example when user equals() or mapping
190	>	* functions take a long time.  However, statistically, this is
191	>	* not a common enough problem to outweigh the time/space overhead
192	>	* of alternatives: Under random hash codes, the frequency of
193	>	* nodes in bins follows a Poisson distribution
194	>	* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
195	>	* parameter of about 0.5 on average, given the resizing threshold
196	>	* of 0.75, although with a large variance because of resizing
197	>	* granularity. Ignoring variance, the expected occurrences of
198	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
199	>	* first few values are:
200	>	*
201	>	* 0:    0.607
202	>	* 1:    0.303
203	>	* 2:    0.076
204	>	* 3:    0.012
205	>	* more: 0.002
206	>	*
207	>	* Lock contention probability for two threads accessing distinct
208	>	* elements is roughly 1 / (8 * #elements).  Function "spread"
209	>	* performs hashCode randomization that improves the likelihood
210	>	* that these assumptions hold unless users define exactly the
211	>	* same value for too many hashCodes.
212	>	*
213	>	* The table is resized when occupancy exceeds an occupancy
214	>	* threshold (nominally, 0.75, but see below).  Only a single
215	>	* thread performs the resize (using field "sizeCtl", to arrange
216	>	* exclusion), but the table otherwise remains usable for reads
217	>	* and updates. Resizing proceeds by transferring bins, one by
218	>	* one, from the table to the next table.  Because we are using
219	>	* power-of-two expansion, the elements from each bin must either
220	>	* stay at same index, or move with a power of two offset. We
221	>	* eliminate unnecessary node creation by catching cases where old
222	>	* nodes can be reused because their next fields won't change.  On
223	>	* average, only about one-sixth of them need cloning when a table
224	>	* doubles. The nodes they replace will be garbage collectable as
225	>	* soon as they are no longer referenced by any reader thread that
226	>	* may be in the midst of concurrently traversing table.  Upon
227	>	* transfer, the old table bin contains only a special forwarding
228	>	* node (with hash field "MOVED") that contains the next table as
229		* its key. On encountering a forwarding node, access and update
230	<	* operations restart, using the new table. To ensure concurrent
231	<	* readability of traversals, transfers must proceed from the last
232	<	* bin (table.length - 1) up towards the first.  Any traversal
233	<	* starting from the first bin can then arrange to move to the new
234	<	* table for the rest of the traversal without revisiting nodes.
235	<	* This constrains bin transfers to a particular order, and so can
236	<	* block indefinitely waiting for the next lock, and other threads
237	<	* cannot help with the transfer. However, expected stalls are
238	<	* infrequent enough to not warrant the additional overhead and
239	<	* complexity of access and iteration schemes that could admit
240	<	* out-of-order or concurrent bin transfers.
241	<	*
242	<	* A similar traversal scheme (not yet implemented) can apply to
243	<	* partial traversals during partitioned aggregate operations.
244	<	* Also, read-only operations give up if ever forwarded to a null
245	<	* table, which provides support for shutdown-style clearing,
246	<	* which is also not currently implemented.
230	>	* operations restart, using the new table.
231	>	*
232	>	* Each bin transfer requires its bin lock. However, unlike other
233	>	* cases, a transfer can skip a bin if it fails to acquire its
234	>	* lock, and revisit it later. Method rebuild maintains a buffer
235	>	* of TRANSFER_BUFFER_SIZE bins that have been skipped because of
236	>	* failure to acquire a lock, and blocks only if none are
237	>	* available (i.e., only very rarely).  The transfer operation
238	>	* must also ensure that all accessible bins in both the old and
239	>	* new table are usable by any traversal.  When there are no lock
240	>	* acquisition failures, this is arranged simply by proceeding
241	>	* from the last bin (table.length - 1) up towards the first.
242	>	* Upon seeing a forwarding node, traversals (see class
243	>	* InternalIterator) arrange to move to the new table without
244	>	* revisiting nodes.  However, when any node is skipped during a
245	>	* transfer, all earlier table bins may have become visible, so
246	>	* are initialized with a reverse-forwarding node back to the old
247	>	* table until the new ones are established. (This sometimes
248	>	* requires transiently locking a forwarding node, which is
249	>	* possible under the above encoding.) These more expensive
250	>	* mechanics trigger only when necessary.
251	>	*
252	>	* The traversal scheme also applies to partial traversals of
253	>	* ranges of bins (via an alternate InternalIterator constructor)
254	>	* to support partitioned aggregate operations (that are not
255	>	* otherwise implemented yet).  Also, read-only operations give up
256	>	* if ever forwarded to a null table, which provides support for
257	>	* shutdown-style clearing, which is also not currently
258	>	* implemented.
259	>	*
260	>	* Lazy table initialization minimizes footprint until first use,
261	>	* and also avoids resizings when the first operation is from a
262	>	* putAll, constructor with map argument, or deserialization.
263	>	* These cases attempt to override the initial capacity settings,
264	>	* but harmlessly fail to take effect in cases of races.
265		*
266		* The element count is maintained using a LongAdder, which avoids
267		* contention on updates but can encounter cache thrashing if read
268	<	* too frequently during concurrent updates. To avoid reading so
268	>	* too frequently during concurrent access. To avoid reading so
269		* often, resizing is normally attempted only upon adding to a bin
270	<	* already holding two or more nodes. Under the default threshold
271	<	* (0.75), and uniform hash distributions, the probability of this
272	<	* occurring at threshold is around 13%, meaning that only about 1
273	<	* in 8 puts check threshold (and after resizing, many fewer do
274	<	* so). But this approximation has high variance for small table
275	<	* sizes, so we check on any collision for sizes <= 64.  Further,
276	<	* to increase the probablity that a resize occurs soon enough, we
277	<	* offset the threshold (see THRESHOLD_OFFSET) by the expected
278	<	* number of puts between checks. This is currently set to 8, in
279	<	* accord with the default load factor. In practice, this is
280	<	* rarely overridden, and in any case is close enough to other
281	<	* plausible values not to waste dynamic probablity computation
282	<	* for more precision.
270	>	* already holding two or more nodes. Under uniform hash
271	>	* distributions, the probability of this occurring at threshold
272	>	* is around 13%, meaning that only about 1 in 8 puts check
273	>	* threshold (and after resizing, many fewer do so). But this
274	>	* approximation has high variance for small table sizes, so we
275	>	* check on any collision for sizes <= 64.
276	>	*
277	>	* Maintaining API and serialization compatibility with previous
278	>	* versions of this class introduces several oddities. Mainly: We
279	>	* leave untouched but unused constructor arguments refering to
280	>	* concurrencyLevel. We accept a loadFactor constructor argument,
281	>	* but apply it only to initial table capacity (which is the only
282	>	* time that we can guarantee to honor it.) We also declare an
283	>	* unused "Segment" class that is instantiated in minimal form
284	>	* only when serializing.
285		*/
286
287		/* ---------------- Constants -------------- */
288
289		/**
290	<	* The smallest allowed table capacity.  Must be a power of 2, at
291	<	* least 2.
290	>	* The largest possible table capacity.  This value must be
291	>	* exactly 1<<30 to stay within Java array allocation and indexing
292	>	* bounds for power of two table sizes, and is further required
293	>	* because the top two bits of 32bit hash fields are used for
294	>	* control purposes.
295		*/
296	<	static final int MINIMUM_CAPACITY = 2;
296	>	private static final int MAXIMUM_CAPACITY = 1 << 30;
297
298		/**
299	<	* The largest allowed table capacity.  Must be a power of 2, at
300	<	* most 1<<30.
299	>	* The default initial table capacity.  Must be a power of 2
300	>	* (i.e., at least 1) and at most MAXIMUM_CAPACITY.
301		*/
302	<	static final int MAXIMUM_CAPACITY = 1 << 30;
302	>	private static final int DEFAULT_CAPACITY = 16;
303
304		/**
305	<	* The default initial table capacity.  Must be a power of 2, at
306	<	* least MINIMUM_CAPACITY and at most MAXIMUM_CAPACITY
305	>	* The largest possible (non-power of two) array size.
306	>	* Needed by toArray and related methods.
307		*/
308	<	static final int DEFAULT_CAPACITY = 16;
308	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
309
310		/**
311	<	* The default load factor for this table, used when not otherwise
312	<	* specified in a constructor.
311	>	* The default concurrency level for this table. Unused but
312	>	* defined for compatibility with previous versions of this class.
313		*/
314	<	static final float DEFAULT_LOAD_FACTOR = 0.75f;
314	>	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
315
316		/**
317	<	* The default concurrency level for this table. Unused, but
318	<	* defined for compatibility with previous versions of this class.
317	>	* The load factor for this table. Overrides of this value in
318	>	* constructors affect only the initial table capacity.  The
319	>	* actual floating point value isn't normally used -- it is
320	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
321	>	* the associated resizing threshold.
322		*/
323	<	static final int DEFAULT_CONCURRENCY_LEVEL = 16;
323	>	private static final float LOAD_FACTOR = 0.75f;
324
325		/**
326	<	* The count value to offset thesholds to compensate for checking
327	<	* for resizing only when inserting into bins with two or more
328	<	* elements. See above for explanation.
326	>	* The buffer size for skipped bins during transfers. The
327	>	* value is arbitrary but should be large enough to avoid
328	>	* most locking stalls during resizes.
329		*/
330	<	static final int THRESHOLD_OFFSET = 8;
330	>	private static final int TRANSFER_BUFFER_SIZE = 32;
331
332	<	/**
333	<	* Special node hash value indicating to use table in node.key
334	<	* Must be negative.
332	>	/*
333	>	* Encodings for special uses of Node hash fields. See above for
334	>	* explanation.
335		*/
336	<	static final int MOVED = -1;
336	>	static final int MOVED     = 0x80000000; // hash field for fowarding nodes
337	>	static final int LOCKED    = 0x40000000; // set/tested only as a bit
338	>	static final int WAITING   = 0xc0000000; // both bits set/tested together
339	>	static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
340
341		/* ---------------- Fields -------------- */
342
343		/**
344		* The array of bins. Lazily initialized upon first insertion.
345	<	* Size is always a power of two. Accessed directly by inner
254	<	* classes.
345	>	* Size is always a power of two. Accessed directly by iterators.
346		*/
347		transient volatile Node[] table;
348
349	<	/** The counter maintaining number of elements. */
349	>	/**
350	>	* The counter maintaining number of elements.
351	>	*/
352		private transient final LongAdder counter;
353	<	/** Nonzero when table is being initialized or resized. Updated via CAS. */
354	<	private transient volatile int resizing;
355	<	/** The target load factor for the table. */
356	<	private transient float loadFactor;
357	<	/** The next element count value upon which to resize the table. */
358	<	private transient int threshold;
359	<	/** The initial capacity of the table. */
360	<	private transient int initCap;
353	>
354	>	/**
355	>	* Table initialization and resizing control.  When negative, the
356	>	* table is being initialized or resized. Otherwise, when table is
357	>	* null, holds the initial table size to use upon creation, or 0
358	>	* for default. After initialization, holds the next element count
359	>	* value upon which to resize the table.
360	>	*/
361	>	private transient volatile int sizeCtl;
362
363		// views
364	<	transient Set<K> keySet;
365	<	transient Set<Map.Entry<K,V>> entrySet;
366	<	transient Collection<V> values;
364	>	private transient KeySet<K,V> keySet;
365	>	private transient Values<K,V> values;
366	>	private transient EntrySet<K,V> entrySet;
367
368	<	/** For serialization compatability. Null unless serialized; see below */
369	<	Segment<K,V>[] segments;
368	>	/** For serialization compatibility. Null unless serialized; see below */
369	>	private Segment<K,V>[] segments;
370
371	<	/**
278	<	* Applies a supplemental hash function to a given hashCode, which
279	<	* defends against poor quality hash functions.  The result must
280	<	* be non-negative, and for reasonable performance must have good
281	<	* avalanche properties; i.e., that each bit of the argument
282	<	* affects each bit (except sign bit) of the result.
283	<	*/
284	<	private static final int spread(int h) {
285	<	// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
286	<	h ^= h >>> 16;
287	<	h *= 0x85ebca6b;
288	<	h ^= h >>> 13;
289	<	h *= 0xc2b2ae35;
290	<	return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit
291	<	}
371	>	/* ---------------- Nodes -------------- */
372
373		/**
374		* Key-value entry. Note that this is never exported out as a
375	<	* user-visible Map.Entry.
375	>	* user-visible Map.Entry (see WriteThroughEntry and SnapshotEntry
376	>	* below). Nodes with a negative hash field are special, and do
377	>	* not contain user keys or values.  Otherwise, keys are never
378	>	* null, and null val fields indicate that a node is in the
379	>	* process of being deleted or created. For purposes of read-only
380	>	* access, a key may be read before a val, but can only be used
381	>	* after checking val to be non-null.
382		*/
383		static final class Node {
384	<	final int hash;
384	>	volatile int hash;
385		final Object key;
386		volatile Object val;
387		volatile Node next;
#	Line 306 | Line 392 | public class ConcurrentHashMapV8<K, V>
392		this.val = val;
393		this.next = next;
394		}
395	+
396	+	/** CompareAndSet the hash field */
397	+	final boolean casHash(int cmp, int val) {
398	+	return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
399	+	}
400	+
401	+	/** The number of spins before blocking for a lock */
402	+	static final int MAX_SPINS =
403	+	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
404	+
405	+	/**
406	+	* Spins a while if LOCKED bit set and this node is the first
407	+	* of its bin, and then sets WAITING bits on hash field and
408	+	* blocks (once) if they are still set.  It is OK for this
409	+	* method to return even if lock is not available upon exit,
410	+	* which enables these simple single-wait mechanics.
411	+	*
412	+	* The corresponding signalling operation is performed within
413	+	* callers: Upon detecting that WAITING has been set when
414	+	* unlocking lock (via a failed CAS from non-waiting LOCKED
415	+	* state), unlockers acquire the sync lock and perform a
416	+	* notifyAll.
417	+	*/
418	+	final void tryAwaitLock(Node[] tab, int i) {
419	+	if (tab != null && i >= 0 && i < tab.length) { // bounds check
420	+	int spins = MAX_SPINS, h;
421	+	while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
422	+	if (spins >= 0) {
423	+	if (--spins == MAX_SPINS >>> 1)
424	+	Thread.yield();  // heuristically yield mid-way
425	+	}
426	+	else if (casHash(h, h | WAITING)) {
427	+	synchronized (this) {
428	+	if (tabAt(tab, i) == this &&
429	+	(hash & WAITING) == WAITING) {
430	+	try {
431	+	wait();
432	+	} catch (InterruptedException ie) {
433	+	Thread.currentThread().interrupt();
434	+	}
435	+	}
436	+	else
437	+	notifyAll(); // possibly won race vs signaller
438	+	}
439	+	break;
440	+	}
441	+	}
442	+	}
443	+	}
444	+
445	+	// Unsafe mechanics for casHash
446	+	private static final sun.misc.Unsafe UNSAFE;
447	+	private static final long hashOffset;
448	+
449	+	static {
450	+	try {
451	+	UNSAFE = getUnsafe();
452	+	Class<?> k = Node.class;
453	+	hashOffset = UNSAFE.objectFieldOffset
454	+	(k.getDeclaredField("hash"));
455	+	} catch (Exception e) {
456	+	throw new Error(e);
457	+	}
458	+	}
459		}
460
461	+	/* ---------------- Table element access -------------- */
462	+
463		/*
464	<	* Volatile access nethods are used for table elements as well as
465	<	* elements of in-progress next table while resizing.  Uses in
466	<	* access and update methods are null checked by callers, and
467	<	* implicitly bounds-checked, relying on the invariants that tab
468	<	* arrays have non-zero size, and all indices are masked with
469	<	* (tab.length - 1) which is never negative and always less than
470	<	* length. The "relaxed" non-volatile forms are used only during
471	<	* table initialization. The only other usage is in
472	<	* HashIterator.advance, which performs explicit checks.
464	>	* Volatile access methods are used for table elements as well as
465	>	* elements of in-progress next table while resizing.  Uses are
466	>	* null checked by callers, and implicitly bounds-checked, relying
467	>	* on the invariants that tab arrays have non-zero size, and all
468	>	* indices are masked with (tab.length - 1) which is never
469	>	* negative and always less than length. Note that, to be correct
470	>	* wrt arbitrary concurrency errors by users, bounds checks must
471	>	* operate on local variables, which accounts for some odd-looking
472	>	* inline assignments below.
473		*/
474
475	<	static final Node tabAt(Node[] tab, int i) { // used in HashIterator
475	>	static final Node tabAt(Node[] tab, int i) { // used by InternalIterator
476		return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
477		}
478
#	Line 332 | Line 484 | public class ConcurrentHashMapV8<K, V>
484		UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
485		}
486
487	<	private static final Node relaxedTabAt(Node[] tab, int i) {
336	<	return (Node)UNSAFE.getObject(tab, ((long)i<<ASHIFT)+ABASE);
337	<	}
487	>	/* ---------------- Internal access and update methods -------------- */
488
489	<	private static final void relaxedSetTabAt(Node[] tab, int i, Node v) {
490	<	UNSAFE.putObject(tab, ((long)i<<ASHIFT)+ABASE, v);
489	>	/**
490	>	* Applies a supplemental hash function to a given hashCode, which
491	>	* defends against poor quality hash functions.  The result must
492	>	* be have the top 2 bits clear. For reasonable performance, this
493	>	* function must have good avalanche properties; i.e., that each
494	>	* bit of the argument affects each bit of the result. (Although
495	>	* we don't care about the unused top 2 bits.)
496	>	*/
497	>	private static final int spread(int h) {
498	>	// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
499	>	h ^= h >>> 16;
500	>	h *= 0x85ebca6b;
501	>	h ^= h >>> 13;
502	>	h *= 0xc2b2ae35;
503	>	return ((h >>> 16) ^ h) & HASH_BITS; // mask out top bits
504		}
505
506	<	/* ---------------- Access and update operations -------------- */
344	<
345	<	/** Implementation for get and containsKey **/
506	>	/** Implementation for get and containsKey */
507		private final Object internalGet(Object k) {
508		int h = spread(k.hashCode());
509	<	Node[] tab = table;
510	<	retry: while (tab != null) {
511	<	Node e = tabAt(tab, (tab.length - 1) & h);
512	<	while (e != null) {
513	<	int eh = e.hash;
353	<	if (eh == h) {
354	<	Object ek = e.key, ev = e.val;
355	<	if (ev != null && ek != null && (k == ek || k.equals(ek)))
356	<	return ev;
357	<	}
358	<	else if (eh < 0) { // bin was moved during resize
359	<	tab = (Node[])e.key;
509	>	retry: for (Node[] tab = table; tab != null;) {
510	>	Node e; Object ek, ev; int eh;    // locals to read fields once
511	>	for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
512	>	if ((eh = e.hash) == MOVED) {
513	>	tab = (Node[])e.key;      // restart with new table
514		continue retry;
515		}
516	<	e = e.next;
516	>	if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
517	>	((ek = e.key) == k || k.equals(ek)))
518	>	return ev;
519		}
520		break;
521		}
522		return null;
523		}
524
525	<	/** Implementation for put and putIfAbsent **/
525	>	/** Implementation for put and putIfAbsent */
526		private final Object internalPut(Object k, Object v, boolean replace) {
527		int h = spread(k.hashCode());
528	<	Object oldVal = null;  // the previous value or null if none
529	<	Node[] tab = table;
530	<	for (;;) {
375	<	Node e; int i;
528	>	Object oldVal = null;               // previous value or null if none
529	>	for (Node[] tab = table;;) {
530	>	int i; Node f; int fh; Object fk, fv;
531		if (tab == null)
532	<	tab = grow(0);
533	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
532	>	tab = initTable();
533	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
534		if (casTabAt(tab, i, null, new Node(h, k, v, null)))
535	<	break;
535	>	break;                   // no lock when adding to empty bin
536		}
537	<	else if (e.hash < 0)
538	<	tab = (Node[])e.key;
539	<	else {
537	>	else if ((fh = f.hash) == MOVED)
538	>	tab = (Node[])f.key;
539	>	else if (!replace && (fh & HASH_BITS) == h && (fv = f.val) != null &&
540	>	((fk = f.key) == k || k.equals(fk))) {
541	>	oldVal = fv;                // precheck 1st node for putIfAbsent
542	>	break;
543	>	}
544	>	else if ((fh & LOCKED) != 0)
545	>	f.tryAwaitLock(tab, i);
546	>	else if (f.casHash(fh, fh | LOCKED)) {
547		boolean validated = false;
548		boolean checkSize = false;
549	<	synchronized (e) {
550	<	Node first = e;
551	<	for (;;) {
552	<	Object ek, ev;
553	<	if ((ev = e.val) == null)
554	<	break;
555	<	if (e.hash == h && (ek = e.key) != null &&
556	<	(k == ek || k.equals(ek))) {
395	<	if (tabAt(tab, i) == first) {
396	<	validated = true;
549	>	try {
550	>	if (tabAt(tab, i) == f) {
551	>	validated = true;    // retry if 1st already deleted
552	>	for (Node e = f;;) {
553	>	Object ek, ev;
554	>	if ((e.hash & HASH_BITS) == h &&
555	>	(ev = e.val) != null &&
556	>	((ek = e.key) == k || k.equals(ek))) {
557		oldVal = ev;
558		if (replace)
559		e.val = v;
560	+	break;
561		}
562	<	break;
563	<	}
403	<	Node last = e;
404	<	if ((e = e.next) == null) {
405	<	if (tabAt(tab, i) == first) {
406	<	validated = true;
562	>	Node last = e;
563	>	if ((e = e.next) == null) {
564		last.next = new Node(h, k, v, null);
565	<	if (last != first || tab.length <= 64)
565	>	if (last != f || tab.length <= 64)
566		checkSize = true;
567	+	break;
568		}
411	–	break;
569		}
570		}
571	+	} finally {                  // unlock and signal if needed
572	+	if (!f.casHash(fh | LOCKED, fh)) {
573	+	f.hash = fh;
574	+	synchronized (f) { f.notifyAll(); };
575	+	}
576		}
577		if (validated) {
578	+	int sc;
579		if (checkSize && tab.length < MAXIMUM_CAPACITY &&
580	<	resizing == 0 && counter.sum() >= threshold)
581	<	grow(0);
580	>	(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc)
581	>	growTable();
582		break;
583		}
584		}
585		}
586		if (oldVal == null)
587	<	counter.increment();
587	>	counter.increment();             // update counter outside of locks
588		return oldVal;
589		}
590
591		/**
592	<	* Covers the four public remove/replace methods: Replaces node
593	<	* value with v, conditional upon match of cv if non-null.  If
594	<	* resulting value is null, delete.
592	>	* Implementation for the four public remove/replace methods:
593	>	* Replaces node value with v, conditional upon match of cv if
594	>	* non-null.  If resulting value is null, delete.
595		*/
596		private final Object internalReplace(Object k, Object v, Object cv) {
597		int h = spread(k.hashCode());
598		Object oldVal = null;
599	<	Node e; int i;
600	<	Node[] tab = table;
601	<	while (tab != null &&
602	<	(e = tabAt(tab, i = (tab.length - 1) & h)) != null) {
603	<	if (e.hash < 0)
604	<	tab = (Node[])e.key;
605	<	else {
599	>	for (Node[] tab = table;;) {
600	>	Node f; int i, fh;
601	>	if (tab == null ||
602	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
603	>	break;
604	>	else if ((fh = f.hash) == MOVED)
605	>	tab = (Node[])f.key;
606	>	else if ((fh & HASH_BITS) != h && f.next == null) // precheck
607	>	break;                          // rules out possible existence
608	>	else if ((fh & LOCKED) != 0)
609	>	f.tryAwaitLock(tab, i);
610	>	else if (f.casHash(fh, fh | LOCKED)) {
611		boolean validated = false;
612		boolean deleted = false;
613	<	synchronized (e) {
614	<	Node pred = null;
615	<	Node first = e;
616	<	for (;;) {
617	<	Object ek, ev;
618	<	if ((ev = e.val) == null)
619	<	break;
620	<	if (e.hash == h && (ek = e.key) != null &&
453	<	(k == ek || k.equals(ek))) {
454	<	if (tabAt(tab, i) == first) {
455	<	validated = true;
613	>	try {
614	>	if (tabAt(tab, i) == f) {
615	>	validated = true;
616	>	for (Node e = f, pred = null;;) {
617	>	Object ek, ev;
618	>	if ((e.hash & HASH_BITS) == h &&
619	>	((ev = e.val) != null) &&
620	>	((ek = e.key) == k || k.equals(ek))) {
621		if (cv == null || cv == ev || cv.equals(ev)) {
622		oldVal = ev;
623		if ((e.val = v) == null) {
#	Line 464 | Line 629 | public class ConcurrentHashMapV8<K, V>
629		setTabAt(tab, i, en);
630		}
631		}
632	+	break;
633		}
634	<	break;
635	<	}
636	<	pred = e;
471	<	if ((e = e.next) == null) {
472	<	if (tabAt(tab, i) == first)
473	<	validated = true;
474	<	break;
634	>	pred = e;
635	>	if ((e = e.next) == null)
636	>	break;
637		}
638		}
639	+	} finally {
640	+	if (!f.casHash(fh | LOCKED, fh)) {
641	+	f.hash = fh;
642	+	synchronized (f) { f.notifyAll(); };
643	+	}
644		}
645		if (validated) {
646		if (deleted)
#	Line 485 | Line 652 | public class ConcurrentHashMapV8<K, V>
652		return oldVal;
653		}
654
655	<	/** Implementation for computeIfAbsent and compute */
655	>	/** Implementation for computeIfAbsent and compute. Like put, but messier. */
656	>	// Todo: Somehow reinstate non-termination check
657		@SuppressWarnings("unchecked")
658		private final V internalCompute(K k,
659	<	MappingFunction<? super K, ? extends V> f,
659	>	MappingFunction<? super K, ? extends V> fn,
660		boolean replace) {
661		int h = spread(k.hashCode());
662		V val = null;
663		boolean added = false;
496	–	boolean validated = false;
664		Node[] tab = table;
665	<	do {
666	<	Node e; int i;
665	>	outer:for (;;) {
666	>	Node f; int i, fh; Object fk, fv;
667		if (tab == null)
668	<	tab = grow(0);
669	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
670	<	Node node = new Node(h, k, null, null);
671	<	synchronized (node) {
672	<	if (casTabAt(tab, i, null, node)) {
673	<	validated = true;
674	<	try {
675	<	val = f.map(k);
676	<	if (val != null) {
677	<	node.val = val;
678	<	added = true;
679	<	}
680	<	} finally {
681	<	if (!added)
682	<	setTabAt(tab, i, null);
668	>	tab = initTable();
669	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
670	>	Node node = new Node(fh = h | LOCKED, k, null, null);
671	>	boolean validated = false;
672	>	if (casTabAt(tab, i, null, node)) {
673	>	validated = true;
674	>	try {
675	>	val = fn.map(k);
676	>	if (val != null) {
677	>	node.val = val;
678	>	added = true;
679	>	}
680	>	} finally {
681	>	if (!added)
682	>	setTabAt(tab, i, null);
683	>	if (!node.casHash(fh, h)) {
684	>	node.hash = h;
685	>	synchronized (node) { node.notifyAll(); };
686		}
687		}
688		}
689	+	if (validated)
690	+	break;
691		}
692	<	else if (e.hash < 0)
693	<	tab = (Node[])e.key;
694	<	else if (Thread.holdsLock(e))
695	<	throw new IllegalStateException("Recursive map computation");
696	<	else {
692	>	else if ((fh = f.hash) == MOVED)
693	>	tab = (Node[])f.key;
694	>	else if (!replace && (fh & HASH_BITS) == h && (fv = f.val) != null &&
695	>	((fk = f.key) == k || k.equals(fk))) {
696	>	if (tabAt(tab, i) == f) {
697	>	val = (V)fv;
698	>	break;
699	>	}
700	>	}
701	>	else if ((fh & LOCKED) != 0)
702	>	f.tryAwaitLock(tab, i);
703	>	else if (f.casHash(fh, fh | LOCKED)) {
704	>	boolean validated = false;
705		boolean checkSize = false;
706	<	synchronized (e) {
707	<	Node first = e;
708	<	for (;;) {
709	<	Object ek, ev;
710	<	if ((ev = e.val) == null)
711	<	break;
712	<	if (e.hash == h && (ek = e.key) != null &&
713	<	(k == ek || k.equals(ek))) {
714	<	if (tabAt(tab, i) == first) {
715	<	validated = true;
536	<	if (replace && (ev = f.map(k)) != null)
537	<	e.val = ev;
706	>	try {
707	>	if (tabAt(tab, i) == f) {
708	>	validated = true;
709	>	for (Node e = f;;) {
710	>	Object ek, ev, v;
711	>	if ((e.hash & HASH_BITS) == h &&
712	>	(ev = e.val) != null &&
713	>	((ek = e.key) == k || k.equals(ek))) {
714	>	if (replace && (v = fn.map(k)) != null)
715	>	ev = e.val = v;
716		val = (V)ev;
717	+	break;
718		}
719	<	break;
720	<	}
721	<	Node last = e;
543	<	if ((e = e.next) == null) {
544	<	if (tabAt(tab, i) == first) {
545	<	validated = true;
546	<	if ((val = f.map(k)) != null) {
719	>	Node last = e;
720	>	if ((e = e.next) == null) {
721	>	if ((val = fn.map(k)) != null) {
722		last.next = new Node(h, k, val, null);
723		added = true;
724	<	if (last != first || tab.length <= 64)
724	>	if (last != f || tab.length <= 64)
725		checkSize = true;
726		}
727	+	break;
728		}
553	–	break;
729		}
730		}
731	+	} finally {
732	+	if (!f.casHash(fh | LOCKED, fh)) {
733	+	f.hash = fh;
734	+	synchronized (f) { f.notifyAll(); };
735	+	}
736	+	}
737	+	if (validated) {
738	+	int sc;
739	+	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
740	+	(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc)
741	+	growTable();
742	+	break;
743		}
557	–	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
558	–	resizing == 0 && counter.sum() >= threshold)
559	–	grow(0);
744		}
745	<	} while (!validated);
745	>	}
746		if (added)
747		counter.increment();
748		return val;
749		}
750
751	<	/*
752	<	* Reclassifies nodes in each bin to new table.  Because we are
569	<	* using power-of-two expansion, the elements from each bin must
570	<	* either stay at same index, or move with a power of two
571	<	* offset. We eliminate unnecessary node creation by catching
572	<	* cases where old nodes can be reused because their next fields
573	<	* won't change.  Statistically, at the default threshold, only
574	<	* about one-sixth of them need cloning when a table doubles. The
575	<	* nodes they replace will be garbage collectable as soon as they
576	<	* are no longer referenced by any reader thread that may be in
577	<	* the midst of concurrently traversing table.
578	<	*
579	<	* Transfers are done from the bottom up to preserve iterator
580	<	* traversability. On each step, the old bin is locked,
581	<	* moved/copied, and then replaced with a forwarding node.
751	>	/**
752	>	* Implementation for clear. Steps through each bin, removing all nodes.
753		*/
754	<	private static final void transfer(Node[] tab, Node[] nextTab) {
755	<	int n = tab.length;
756	<	int mask = nextTab.length - 1;
757	<	Node fwd = new Node(MOVED, nextTab, null, null);
758	<	for (int i = n - 1; i >= 0; --i) {
759	<	for (Node e;;) {
760	<	if ((e = tabAt(tab, i)) == null) {
761	<	if (casTabAt(tab, i, e, fwd))
762	<	break;
763	<	}
764	<	else {
765	<	boolean validated = false;
766	<	synchronized (e) {
767	<	int idx = e.hash & mask;
768	<	Node lastRun = e;
769	<	for (Node p = e.next; p != null; p = p.next) {
770	<	int j = p.hash & mask;
771	<	if (j != idx) {
772	<	idx = j;
773	<	lastRun = p;
774	<	}
775	<	}
605	<	if (tabAt(tab, i) == e) {
606	<	validated = true;
607	<	relaxedSetTabAt(nextTab, idx, lastRun);
608	<	for (Node p = e; p != lastRun; p = p.next) {
609	<	int h = p.hash;
610	<	int j = h & mask;
611	<	Node r = relaxedTabAt(nextTab, j);
612	<	relaxedSetTabAt(nextTab, j,
613	<	new Node(h, p.key, p.val, r));
754	>	private final void internalClear() {
755	>	long delta = 0L; // negative number of deletions
756	>	int i = 0;
757	>	Node[] tab = table;
758	>	while (tab != null && i < tab.length) {
759	>	int fh;
760	>	Node f = tabAt(tab, i);
761	>	if (f == null)
762	>	++i;
763	>	else if ((fh = f.hash) == MOVED)
764	>	tab = (Node[])f.key;
765	>	else if ((fh & LOCKED) != 0)
766	>	f.tryAwaitLock(tab, i);
767	>	else if (f.casHash(fh, fh | LOCKED)) {
768	>	boolean validated = false;
769	>	try {
770	>	if (tabAt(tab, i) == f) {
771	>	validated = true;
772	>	for (Node e = f; e != null; e = e.next) {
773	>	if (e.val != null) { // currently always true
774	>	e.val = null;
775	>	--delta;
776		}
615	–	setTabAt(tab, i, fwd);
777		}
778	+	setTabAt(tab, i, null);
779	+	}
780	+	} finally {
781	+	if (!f.casHash(fh | LOCKED, fh)) {
782	+	f.hash = fh;
783	+	synchronized (f) { f.notifyAll(); };
784		}
618	–	if (validated)
619	–	break;
785		}
786	+	if (validated)
787	+	++i;
788		}
789		}
790	+	counter.add(delta);
791		}
792
793	+	/* ----------------Table Initialization and Resizing -------------- */
794	+
795		/**
796	<	* If not already resizing, initializes or creates next table and
797	<	* transfers bins. Rechecks occupancy after a transfer to see if
798	<	* another resize is already needed because resizings are lagging
799	<	* additions.
800	<	*
801	<	* @param sizeHint overridden capacity target (nonzero only from putAll)
802	<	* @return current table
803	<	*/
804	<	private final Node[] grow(int sizeHint) {
805	<	if (resizing == 0 &&
806	<	UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
807	<	try {
808	<	for (;;) {
809	<	int cap, n;
810	<	Node[] tab = table;
811	<	if (tab == null) {
812	<	int c = initCap;
813	<	if (c < sizeHint)
814	<	c = sizeHint;
815	<	if (c == DEFAULT_CAPACITY)
816	<	cap = c;
817	<	else if (c >= MAXIMUM_CAPACITY)
818	<	cap = MAXIMUM_CAPACITY;
819	<	else {
820	<	cap = MINIMUM_CAPACITY;
821	<	while (cap < c)
822	<	cap <<= 1;
653	<	}
796	>	* Returns a power of two table size for the given desired capacity.
797	>	* See Hackers Delight, sec 3.2
798	>	*/
799	>	private static final int tableSizeFor(int c) {
800	>	int n = c - 1;
801	>	n |= n >>> 1;
802	>	n |= n >>> 2;
803	>	n |= n >>> 4;
804	>	n |= n >>> 8;
805	>	n |= n >>> 16;
806	>	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
807	>	}
808	>
809	>	/**
810	>	* Initializes table, using the size recorded in sizeCtl.
811	>	*/
812	>	private final Node[] initTable() {
813	>	Node[] tab; int sc;
814	>	while ((tab = table) == null) {
815	>	if ((sc = sizeCtl) < 0)
816	>	Thread.yield(); // lost initialization race; just spin
817	>	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
818	>	try {
819	>	if ((tab = table) == null) {
820	>	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
821	>	tab = table = new Node[n];
822	>	sc = n - (n >>> 2) - 1;
823		}
824	<	else if ((n = tab.length) < MAXIMUM_CAPACITY &&
825	<	(sizeHint <= 0 || n < sizeHint))
657	<	cap = n << 1;
658	<	else
659	<	break;
660	<	threshold = (int)(cap * loadFactor) - THRESHOLD_OFFSET;
661	<	Node[] nextTab = new Node[cap];
662	<	if (tab != null)
663	<	transfer(tab, nextTab);
664	<	table = nextTab;
665	<	if (tab == null || cap >= MAXIMUM_CAPACITY ||
666	<	(sizeHint > 0 && cap >= sizeHint) ||
667	<	counter.sum() < threshold)
668	<	break;
824	>	} finally {
825	>	sizeCtl = sc;
826		}
827	<	} finally {
671	<	resizing = 0;
827	>	break;
828		}
829		}
830	<	else if (table == null)
675	<	Thread.yield(); // lost initialization race; just spin
676	<	return table;
830	>	return tab;
831		}
832
833		/**
834	<	* Implementation for putAll and constructor with Map
835	<	* argument. Tries to first override initial capacity or grow
836	<	* based on map size to pre-allocate table space.
834	>	* If not already resizing, creates next table and transfers bins.
835	>	* Rechecks occupancy after a transfer to see if another resize is
836	>	* already needed because resizings are lagging additions.
837		*/
838	<	private final void internalPutAll(Map<? extends K, ? extends V> m) {
839	<	int s = m.size();
840	<	grow((s >= (MAXIMUM_CAPACITY >>> 1)) ? s : s + (s >>> 1));
841	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
842	<	Object k = e.getKey();
843	<	Object v = e.getValue();
844	<	if (k == null || v == null)
845	<	throw new NullPointerException();
846	<	internalPut(k, v, true);
838	>	private final void growTable() {
839	>	int sc = sizeCtl;
840	>	if (sc >= 0 && UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
841	>	try {
842	>	Node[] tab; int n;
843	>	while ((tab = table) != null &&
844	>	(n = tab.length) > 0 && n < MAXIMUM_CAPACITY &&
845	>	counter.sum() >= (long)sc) {
846	>	table = rebuild(tab);
847	>	sc = (n << 1) - (n >>> 1) - 1;
848	>	}
849	>	} finally {
850	>	sizeCtl = sc;
851	>	}
852		}
853		}
854
855	<	/**
856	<	* Implementation for clear. Steps through each bin, removing all nodes.
855	>	/*
856	>	* Moves and/or copies the nodes in each bin to new table. See
857	>	* above for explanation.
858	>	*
859	>	* @return the new table
860		*/
861	<	private final void internalClear() {
862	<	long deletions = 0L;
863	<	int i = 0;
864	<	Node[] tab = table;
865	<	while (tab != null && i < tab.length) {
866	<	Node e = tabAt(tab, i);
867	<	if (e == null)
868	<	++i;
869	<	else if (e.hash < 0)
870	<	tab = (Node[])e.key;
871	<	else {
861	>	private static final Node[] rebuild(Node[] tab) {
862	>	int n = tab.length;
863	>	Node[] nextTab = new Node[n << 1];
864	>	Node fwd = new Node(MOVED, nextTab, null, null);
865	>	int[] buffer = null;       // holds bins to revisit; null until needed
866	>	Node rev = null;           // reverse forwarder; null until needed
867	>	int nbuffered = 0;         // the number of bins in buffer list
868	>	int bufferIndex = 0;       // buffer index of current buffered bin
869	>	int bin = n - 1;           // current non-buffered bin or -1 if none
870	>
871	>	for (int i = bin;;) {      // start upwards sweep
872	>	int fh; Node f;
873	>	if ((f = tabAt(tab, i)) == null) {
874	>	if (bin >= 0) {    // no lock needed (or available)
875	>	if (!casTabAt(tab, i, f, fwd))
876	>	continue;
877	>	}
878	>	else {             // transiently use a locked forwarding node
879	>	Node g =  new Node(MOVED|LOCKED, nextTab, null, null);
880	>	if (!casTabAt(tab, i, f, g))
881	>	continue;
882	>	setTabAt(nextTab, i, null);
883	>	setTabAt(nextTab, i + n, null);
884	>	setTabAt(tab, i, fwd);
885	>	if (!g.casHash(MOVED|LOCKED, MOVED)) {
886	>	g.hash = MOVED;
887	>	synchronized (g) { g.notifyAll(); }
888	>	}
889	>	}
890	>	}
891	>	else if (((fh = f.hash) & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
892		boolean validated = false;
893	<	synchronized (e) {
894	<	if (tabAt(tab, i) == e) {
893	>	try {              // split to lo and hi lists; copying as needed
894	>	if (tabAt(tab, i) == f) {
895		validated = true;
896	<	do {
897	<	if (e.val != null) {
898	<	e.val = null;
899	<	++deletions;
896	>	Node e = f, lastRun = f;
897	>	Node lo = null, hi = null;
898	>	int runBit = e.hash & n;
899	>	for (Node p = e.next; p != null; p = p.next) {
900	>	int b = p.hash & n;
901	>	if (b != runBit) {
902	>	runBit = b;
903	>	lastRun = p;
904		}
905	<	} while ((e = e.next) != null);
906	<	setTabAt(tab, i, null);
905	>	}
906	>	if (runBit == 0)
907	>	lo = lastRun;
908	>	else
909	>	hi = lastRun;
910	>	for (Node p = e; p != lastRun; p = p.next) {
911	>	int ph = p.hash & HASH_BITS;
912	>	Object pk = p.key, pv = p.val;
913	>	if ((ph & n) == 0)
914	>	lo = new Node(ph, pk, pv, lo);
915	>	else
916	>	hi = new Node(ph, pk, pv, hi);
917	>	}
918	>	setTabAt(nextTab, i, lo);
919	>	setTabAt(nextTab, i + n, hi);
920	>	setTabAt(tab, i, fwd);
921		}
922	<	}
923	<	if (validated) {
924	<	++i;
925	<	if (deletions > THRESHOLD_OFFSET) { // bound lag in counts
726	<	counter.add(-deletions);
727	<	deletions = 0L;
922	>	} finally {
923	>	if (!f.casHash(fh | LOCKED, fh)) {
924	>	f.hash = fh;
925	>	synchronized (f) { f.notifyAll(); };
926		}
927		}
928	+	if (!validated)
929	+	continue;
930		}
731	–	}
732	–	if (deletions != 0L)
733	–	counter.add(-deletions);
734	–	}
735	–
736	–	/**
737	–	* Base class for key, value, and entry iterators, plus internal
738	–	* implementations of public traversal-based methods, to avoid
739	–	* duplicating traversal code.
740	–	*/
741	–	class HashIterator {
742	–	private Node next;          // the next entry to return
743	–	private Node[] tab;         // current table; updated if resized
744	–	private Node lastReturned;  // the last entry returned, for remove
745	–	private Object nextVal;     // cached value of next
746	–	private int index;          // index of bin to use next
747	–	private int baseIndex;      // current index of initial table
748	–	private final int baseSize; // initial table size
749	–
750	–	HashIterator() {
751	–	Node[] t = tab = table;
752	–	if (t == null)
753	–	baseSize = 0;
931		else {
932	<	baseSize = t.length;
933	<	advance(null);
934	<	}
935	<	}
936	<
937	<	public final boolean hasNext()         { return next != null; }
938	<	public final boolean hasMoreElements() { return next != null; }
762	<
763	<	/**
764	<	* Advances next.  Normally, iteration proceeds bin-by-bin
765	<	* traversing lists.  However, if the table has been resized,
766	<	* then all future steps must traverse both the bin at the
767	<	* current index as well as at (index + baseSize); and so on
768	<	* for further resizings. To paranoically cope with potential
769	<	* (improper) sharing of iterators across threads, table reads
770	<	* are bounds-checked.
771	<	*/
772	<	final void advance(Node e) {
773	<	for (;;) {
774	<	Node[] t; int i; // for bounds checks
775	<	if (e != null) {
776	<	Object ek = e.key, ev = e.val;
777	<	if (ev != null && ek != null) {
778	<	nextVal = ev;
779	<	next = e;
780	<	break;
781	<	}
782	<	e = e.next;
932	>	if (buffer == null) // initialize buffer for revisits
933	>	buffer = new int[TRANSFER_BUFFER_SIZE];
934	>	if (bin < 0 && bufferIndex > 0) {
935	>	int j = buffer[--bufferIndex];
936	>	buffer[bufferIndex] = i;
937	>	i = j;         // swap with another bin
938	>	continue;
939		}
940	<	else if (baseIndex < baseSize && (t = tab) != null &&
941	<	t.length > (i = index) && i >= 0) {
942	<	if ((e = tabAt(t, i)) != null && e.hash < 0) {
787	<	tab = (Node[])e.key;
788	<	e = null;
789	<	}
790	<	else if (i + baseSize < t.length)
791	<	index += baseSize;    // visit forwarded upper slots
792	<	else
793	<	index = ++baseIndex;
940	>	if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
941	>	f.tryAwaitLock(tab, i);
942	>	continue;      // no other options -- block
943		}
944	<	else {
945	<	next = null;
946	<	break;
947	<	}
948	<	}
949	<	}
950	<
802	<	final Object nextKey() {
803	<	Node e = next;
804	<	if (e == null)
805	<	throw new NoSuchElementException();
806	<	Object k = e.key;
807	<	advance((lastReturned = e).next);
808	<	return k;
809	<	}
810	<
811	<	final Object nextValue() {
812	<	Node e = next;
813	<	if (e == null)
814	<	throw new NoSuchElementException();
815	<	Object v = nextVal;
816	<	advance((lastReturned = e).next);
817	<	return v;
818	<	}
819	<
820	<	final WriteThroughEntry nextEntry() {
821	<	Node e = next;
822	<	if (e == null)
823	<	throw new NoSuchElementException();
824	<	WriteThroughEntry entry =
825	<	new WriteThroughEntry(e.key, nextVal);
826	<	advance((lastReturned = e).next);
827	<	return entry;
828	<	}
829	<
830	<	public final void remove() {
831	<	if (lastReturned == null)
832	<	throw new IllegalStateException();
833	<	ConcurrentHashMapV8.this.remove(lastReturned.key);
834	<	lastReturned = null;
835	<	}
836	<
837	<	/** Helper for serialization */
838	<	final void writeEntries(java.io.ObjectOutputStream s)
839	<	throws java.io.IOException {
840	<	Node e;
841	<	while ((e = next) != null) {
842	<	s.writeObject(e.key);
843	<	s.writeObject(nextVal);
844	<	advance(e.next);
944	>	if (rev == null)   // initialize reverse-forwarder
945	>	rev = new Node(MOVED, tab, null, null);
946	>	if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
947	>	continue;      // recheck before adding to list
948	>	buffer[nbuffered++] = i;
949	>	setTabAt(nextTab, i, rev);     // install place-holders
950	>	setTabAt(nextTab, i + n, rev);
951		}
846	–	}
952
953	<	/** Helper for containsValue */
954	<	final boolean containsVal(Object value) {
955	<	if (value != null) {
956	<	Node e;
957	<	while ((e = next) != null) {
853	<	Object v = nextVal;
854	<	if (value == v || value.equals(v))
855	<	return true;
856	<	advance(e.next);
857	<	}
953	>	if (bin > 0)
954	>	i = --bin;
955	>	else if (buffer != null && nbuffered > 0) {
956	>	bin = -1;
957	>	i = buffer[bufferIndex = --nbuffered];
958		}
959	<	return false;
959	>	else
960	>	return nextTab;
961		}
962	+	}
963
964	<	/** Helper for Map.hashCode */
863	<	final int mapHashCode() {
864	<	int h = 0;
865	<	Node e;
866	<	while ((e = next) != null) {
867	<	h += e.key.hashCode() ^ nextVal.hashCode();
868	<	advance(e.next);
869	<	}
870	<	return h;
871	<	}
964	>	/* ----------------Table Traversal -------------- */
965
966	<	/** Helper for Map.toString */
967	<	final String mapToString() {
968	<	Node e = next;
969	<	if (e == null)
970	<	return "{}";
971	<	StringBuilder sb = new StringBuilder();
972	<	sb.append('{');
973	<	for (;;) {
974	<	sb.append(e.key   == this ? "(this Map)" : e.key);
975	<	sb.append('=');
976	<	sb.append(nextVal == this ? "(this Map)" : nextVal);
977	<	advance(e.next);
978	<	if ((e = next) != null)
979	<	sb.append(',').append(' ');
980	<	else
981	<	return sb.append('}').toString();
982	<	}
966	>	/**
967	>	* Encapsulates traversal for methods such as containsValue; also
968	>	* serves as a base class for other iterators.
969	>	*
970	>	* At each step, the iterator snapshots the key ("nextKey") and
971	>	* value ("nextVal") of a valid node (i.e., one that, at point of
972	>	* snapshot, has a nonnull user value). Because val fields can
973	>	* change (including to null, indicating deletion), field nextVal
974	>	* might not be accurate at point of use, but still maintains the
975	>	* weak consistency property of holding a value that was once
976	>	* valid.
977	>	*
978	>	* Internal traversals directly access these fields, as in:
979	>	* {@code while (it.next != null) { process(it.nextKey); it.advance(); }}
980	>	*
981	>	* Exported iterators (subclasses of ViewIterator) extract key,
982	>	* value, or key-value pairs as return values of Iterator.next(),
983	>	* and encapsulate the it.next check as hasNext();
984	>	*
985	>	* The iterator visits each valid node that was reachable upon
986	>	* iterator construction once. It might miss some that were added
987	>	* to a bin after the bin was visited, which is OK wrt consistency
988	>	* guarantees. Maintaining this property in the face of possible
989	>	* ongoing resizes requires a fair amount of bookkeeping state
990	>	* that is difficult to optimize away amidst volatile accesses.
991	>	* Even so, traversal maintains reasonable throughput.
992	>	*
993	>	* Normally, iteration proceeds bin-by-bin traversing lists.
994	>	* However, if the table has been resized, then all future steps
995	>	* must traverse both the bin at the current index as well as at
996	>	* (index + baseSize); and so on for further resizings. To
997	>	* paranoically cope with potential sharing by users of iterators
998	>	* across threads, iteration terminates if a bounds checks fails
999	>	* for a table read.
1000	>	*
1001	>	* The range-based constructor enables creation of parallel
1002	>	* range-splitting traversals. (Not yet implemented.)
1003	>	*/
1004	>	static class InternalIterator {
1005	>	Node next;           // the next entry to use
1006	>	Node last;           // the last entry used
1007	>	Object nextKey;      // cached key field of next
1008	>	Object nextVal;      // cached val field of next
1009	>	Node[] tab;          // current table; updated if resized
1010	>	int index;           // index of bin to use next
1011	>	int baseIndex;       // current index of initial table
1012	>	final int baseLimit; // index bound for initial table
1013	>	final int baseSize;  // initial table size
1014	>
1015	>	/** Creates iterator for all entries in the table. */
1016	>	InternalIterator(Node[] tab) {
1017	>	this.tab = tab;
1018	>	baseLimit = baseSize = (tab == null) ? 0 : tab.length;
1019	>	index = baseIndex = 0;
1020	>	next = null;
1021	>	advance();
1022	>	}
1023	>
1024	>	/** Creates iterator for the given range of the table */
1025	>	InternalIterator(Node[] tab, int lo, int hi) {
1026	>	this.tab = tab;
1027	>	baseSize = (tab == null) ? 0 : tab.length;
1028	>	baseLimit = (hi <= baseSize) ? hi : baseSize;
1029	>	index = baseIndex = lo;
1030	>	next = null;
1031	>	advance();
1032	>	}
1033	>
1034	>	/** Advances next. See above for explanation. */
1035	>	final void advance() {
1036	>	Node e = last = next;
1037	>	outer: do {
1038	>	if (e != null)                  // advance past used/skipped node
1039	>	e = e.next;
1040	>	while (e == null) {             // get to next non-null bin
1041	>	Node[] t; int b, i, n;      // checks must use locals
1042	>	if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
1043	>	(t = tab) == null || i >= (n = t.length))
1044	>	break outer;
1045	>	else if ((e = tabAt(t, i)) != null && e.hash == MOVED)
1046	>	tab = (Node[])e.key;    // restarts due to null val
1047	>	else                        // visit upper slots if present
1048	>	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
1049	>	}
1050	>	nextKey = e.key;
1051	>	} while ((nextVal = e.val) == null);// skip deleted or special nodes
1052	>	next = e;
1053		}
1054		}
1055
1056		/* ---------------- Public operations -------------- */
1057
1058		/**
1059	<	* Creates a new, empty map with the specified initial
897	<	* capacity, load factor and concurrency level.
898	<	*
899	<	* @param initialCapacity the initial capacity. The implementation
900	<	* performs internal sizing to accommodate this many elements.
901	<	* @param loadFactor  the load factor threshold, used to control resizing.
902	<	* Resizing may be performed when the average number of elements per
903	<	* bin exceeds this threshold.
904	<	* @param concurrencyLevel the estimated number of concurrently
905	<	* updating threads. The implementation may use this value as
906	<	* a sizing hint.
907	<	* @throws IllegalArgumentException if the initial capacity is
908	<	* negative or the load factor or concurrencyLevel are
909	<	* nonpositive.
1059	>	* Creates a new, empty map with the default initial table size (16),
1060		*/
1061	<	public ConcurrentHashMapV8(int initialCapacity,
912	<	float loadFactor, int concurrencyLevel) {
913	<	if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0)
914	<	throw new IllegalArgumentException();
915	<	this.initCap = initialCapacity;
916	<	this.loadFactor = loadFactor;
1061	>	public ConcurrentHashMapV8() {
1062		this.counter = new LongAdder();
1063		}
1064
1065		/**
1066	<	* Creates a new, empty map with the specified initial capacity
1067	<	* and load factor and with the default concurrencyLevel (16).
1066	>	* Creates a new, empty map with an initial table size
1067	>	* accommodating the specified number of elements without the need
1068	>	* to dynamically resize.
1069		*
1070		* @param initialCapacity The implementation performs internal
1071		* sizing to accommodate this many elements.
926	–	* @param loadFactor  the load factor threshold, used to control resizing.
927	–	* Resizing may be performed when the average number of elements per
928	–	* bin exceeds this threshold.
1072		* @throws IllegalArgumentException if the initial capacity of
1073	<	* elements is negative or the load factor is nonpositive
931	<	*
932	<	* @since 1.6
1073	>	* elements is negative
1074		*/
1075	<	public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
1076	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
1075	>	public ConcurrentHashMapV8(int initialCapacity) {
1076	>	if (initialCapacity < 0)
1077	>	throw new IllegalArgumentException();
1078	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
1079	>	MAXIMUM_CAPACITY :
1080	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
1081	>	this.counter = new LongAdder();
1082	>	this.sizeCtl = cap;
1083		}
1084
1085		/**
1086	<	* Creates a new, empty map with the specified initial capacity,
940	<	* and with default load factor (0.75) and concurrencyLevel (16).
1086	>	* Creates a new map with the same mappings as the given map.
1087		*
1088	<	* @param initialCapacity the initial capacity. The implementation
943	<	* performs internal sizing to accommodate this many elements.
944	<	* @throws IllegalArgumentException if the initial capacity of
945	<	* elements is negative.
1088	>	* @param m the map
1089		*/
1090	<	public ConcurrentHashMapV8(int initialCapacity) {
1091	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1090	>	public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
1091	>	this.counter = new LongAdder();
1092	>	this.sizeCtl = DEFAULT_CAPACITY;
1093	>	putAll(m);
1094		}
1095
1096		/**
1097	<	* Creates a new, empty map with a default initial capacity (16),
1098	<	* load factor (0.75) and concurrencyLevel (16).
1097	>	* Creates a new, empty map with an initial table size based on
1098	>	* the given number of elements ({@code initialCapacity}) and
1099	>	* initial table density ({@code loadFactor}).
1100	>	*
1101	>	* @param initialCapacity the initial capacity. The implementation
1102	>	* performs internal sizing to accommodate this many elements,
1103	>	* given the specified load factor.
1104	>	* @param loadFactor the load factor (table density) for
1105	>	* establishing the initial table size
1106	>	* @throws IllegalArgumentException if the initial capacity of
1107	>	* elements is negative or the load factor is nonpositive
1108	>	*
1109	>	* @since 1.6
1110		*/
1111	<	public ConcurrentHashMapV8() {
1112	<	this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1111	>	public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
1112	>	this(initialCapacity, loadFactor, 1);
1113		}
1114
1115		/**
1116	<	* Creates a new map with the same mappings as the given map.
1117	<	* The map is created with a capacity of 1.5 times the number
1118	<	* of mappings in the given map or 16 (whichever is greater),
1119	<	* and a default load factor (0.75) and concurrencyLevel (16).
1116	>	* Creates a new, empty map with an initial table size based on
1117	>	* the given number of elements ({@code initialCapacity}), table
1118	>	* density ({@code loadFactor}), and number of concurrently
1119	>	* updating threads ({@code concurrencyLevel}).
1120		*
1121	<	* @param m the map
1121	>	* @param initialCapacity the initial capacity. The implementation
1122	>	* performs internal sizing to accommodate this many elements,
1123	>	* given the specified load factor.
1124	>	* @param loadFactor the load factor (table density) for
1125	>	* establishing the initial table size
1126	>	* @param concurrencyLevel the estimated number of concurrently
1127	>	* updating threads. The implementation may use this value as
1128	>	* a sizing hint.
1129	>	* @throws IllegalArgumentException if the initial capacity is
1130	>	* negative or the load factor or concurrencyLevel are
1131	>	* nonpositive
1132		*/
1133	<	public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
1134	<	this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1135	<	if (m == null)
1136	<	throw new NullPointerException();
1137	<	internalPutAll(m);
1133	>	public ConcurrentHashMapV8(int initialCapacity,
1134	>	float loadFactor, int concurrencyLevel) {
1135	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
1136	>	throw new IllegalArgumentException();
1137	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
1138	>	initialCapacity = concurrencyLevel;   // as estimated threads
1139	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
1140	>	int cap =  ((size >= (long)MAXIMUM_CAPACITY) ?
1141	>	MAXIMUM_CAPACITY: tableSizeFor((int)size));
1142	>	this.counter = new LongAdder();
1143	>	this.sizeCtl = cap;
1144		}
1145
1146		/**
1147	<	* Returns {@code true} if this map contains no key-value mappings.
976	<	*
977	<	* @return {@code true} if this map contains no key-value mappings
1147	>	* {@inheritDoc}
1148		*/
1149		public boolean isEmpty() {
1150		return counter.sum() <= 0L; // ignore transient negative values
1151		}
1152
1153		/**
1154	<	* Returns the number of key-value mappings in this map.  If the
985	<	* map contains more than {@code Integer.MAX_VALUE} elements, returns
986	<	* {@code Integer.MAX_VALUE}.
987	<	*
988	<	* @return the number of key-value mappings in this map
1154	>	* {@inheritDoc}
1155		*/
1156		public int size() {
1157		long n = counter.sum();
1158	<	return ((n >>> 31) == 0) ? (int)n : (n < 0L) ? 0 : Integer.MAX_VALUE;
1158	>	return ((n < 0L) ? 0 :
1159	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
1160	>	(int)n);
1161	>	}
1162	>
1163	>	final long longSize() { // accurate version of size needed for views
1164	>	long n = counter.sum();
1165	>	return (n < 0L) ? 0L : n;
1166		}
1167
1168		/**
#	Line 1016 | Line 1189 | public class ConcurrentHashMapV8<K, V>
1189		* @param  key   possible key
1190		* @return {@code true} if and only if the specified object
1191		*         is a key in this table, as determined by the
1192	<	*         {@code equals} method; {@code false} otherwise.
1192	>	*         {@code equals} method; {@code false} otherwise
1193		* @throws NullPointerException if the specified key is null
1194		*/
1195		public boolean containsKey(Object key) {
#	Line 1027 | Line 1200 | public class ConcurrentHashMapV8<K, V>
1200
1201		/**
1202		* Returns {@code true} if this map maps one or more keys to the
1203	<	* specified value. Note: This method requires a full internal
1204	<	* traversal of the hash table, and so is much slower than
1032	<	* method {@code containsKey}.
1203	>	* specified value. Note: This method may require a full traversal
1204	>	* of the map, and is much slower than method {@code containsKey}.
1205		*
1206		* @param value value whose presence in this map is to be tested
1207		* @return {@code true} if this map maps one or more keys to the
#	Line 1039 | Line 1211 | public class ConcurrentHashMapV8<K, V>
1211		public boolean containsValue(Object value) {
1212		if (value == null)
1213		throw new NullPointerException();
1214	<	return new HashIterator().containsVal(value);
1214	>	Object v;
1215	>	InternalIterator it = new InternalIterator(table);
1216	>	while (it.next != null) {
1217	>	if ((v = it.nextVal) == value || value.equals(v))
1218	>	return true;
1219	>	it.advance();
1220	>	}
1221	>	return false;
1222		}
1223
1224		/**
#	Line 1105 | Line 1284 | public class ConcurrentHashMapV8<K, V>
1284		public void putAll(Map<? extends K, ? extends V> m) {
1285		if (m == null)
1286		throw new NullPointerException();
1287	<	internalPutAll(m);
1287	>	/*
1288	>	* If uninitialized, try to preallocate big enough table
1289	>	*/
1290	>	if (table == null) {
1291	>	int size = m.size();
1292	>	int n = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1293	>	tableSizeFor(size + (size >>> 1) + 1);
1294	>	int sc = sizeCtl;
1295	>	if (n < sc)
1296	>	n = sc;
1297	>	if (sc >= 0 &&
1298	>	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1299	>	try {
1300	>	if (table == null) {
1301	>	table = new Node[n];
1302	>	sc = n - (n >>> 2) - 1;
1303	>	}
1304	>	} finally {
1305	>	sizeCtl = sc;
1306	>	}
1307	>	}
1308	>	}
1309	>	for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
1310	>	Object ek = e.getKey(), ev = e.getValue();
1311	>	if (ek == null || ev == null)
1312	>	throw new NullPointerException();
1313	>	internalPut(ek, ev, true);
1314	>	}
1315		}
1316
1317		/**
1318		* If the specified key is not already associated with a value,
1319		* computes its value using the given mappingFunction, and if
1320		* non-null, enters it into the map.  This is equivalent to
1321	<	*
1322	<	* <pre>
1323	<	*   if (map.containsKey(key))
1324	<	*       return map.get(key);
1325	<	*   value = mappingFunction.map(key);
1326	<	*   if (value != null)
1327	<	*      map.put(key, value);
1122	<	*   return value;
1123	<	* </pre>
1321	>	*  <pre> {@code
1322	>	* if (map.containsKey(key))
1323	>	*   return map.get(key);
1324	>	* value = mappingFunction.map(key);
1325	>	* if (value != null)
1326	>	*   map.put(key, value);
1327	>	* return value;}</pre>
1328		*
1329		* except that the action is performed atomically.  Some attempted
1330		* update operations on this map by other threads may be blocked
#	Line 1129 | Line 1333 | public class ConcurrentHashMapV8<K, V>
1333		* mappings of this Map. The most appropriate usage is to
1334		* construct a new object serving as an initial mapped value, or
1335		* memoized result, as in:
1336	<	* <pre>{@code
1336	>	*  <pre> {@code
1337		* map.computeIfAbsent(key, new MappingFunction<K, V>() {
1338	<	*   public V map(K k) { return new Value(f(k)); }};
1135	<	* }</pre>
1338	>	*   public V map(K k) { return new Value(f(k)); }});}</pre>
1339		*
1340		* @param key key with which the specified value is to be associated
1341		* @param mappingFunction the function to compute a value
1342		* @return the current (existing or computed) value associated with
1343		*         the specified key, or {@code null} if the computation
1344	<	*         returned {@code null}.
1344	>	*         returned {@code null}
1345		* @throws NullPointerException if the specified key or mappingFunction
1346	<	*         is null,
1346	>	*         is null
1347		* @throws IllegalStateException if the computation detectably
1348		*         attempts a recursive update to this map that would
1349	<	*         otherwise never complete.
1349	>	*         otherwise never complete
1350		* @throws RuntimeException or Error if the mappingFunction does so,
1351	<	*         in which case the mapping is left unestablished.
1351	>	*         in which case the mapping is left unestablished
1352		*/
1353		public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
1354		if (key == null || mappingFunction == null)
#	Line 1157 | Line 1360 | public class ConcurrentHashMapV8<K, V>
1360		* Computes the value associated with the given key using the given
1361		* mappingFunction, and if non-null, enters it into the map.  This
1362		* is equivalent to
1363	<	*
1364	<	* <pre>
1365	<	*   value = mappingFunction.map(key);
1366	<	*   if (value != null)
1367	<	*      map.put(key, value);
1368	<	*   else
1369	<	*      value = map.get(key);
1167	<	*   return value;
1168	<	* </pre>
1363	>	*  <pre> {@code
1364	>	* value = mappingFunction.map(key);
1365	>	* if (value != null)
1366	>	*   map.put(key, value);
1367	>	* else
1368	>	*   value = map.get(key);
1369	>	* return value;}</pre>
1370		*
1371		* except that the action is performed atomically.  Some attempted
1372		* update operations on this map by other threads may be blocked
#	Line 1177 | Line 1378 | public class ConcurrentHashMapV8<K, V>
1378		* @param mappingFunction the function to compute a value
1379		* @return the current value associated with
1380		*         the specified key, or {@code null} if the computation
1381	<	*         returned {@code null} and the value was not otherwise present.
1381	>	*         returned {@code null} and the value was not otherwise present
1382		* @throws NullPointerException if the specified key or mappingFunction
1383	<	*         is null,
1383	>	*         is null
1384		* @throws IllegalStateException if the computation detectably
1385		*         attempts a recursive update to this map that would
1386	<	*         otherwise never complete.
1386	>	*         otherwise never complete
1387		* @throws RuntimeException or Error if the mappingFunction does so,
1388	<	*         in which case the mapping is unchanged.
1388	>	*         in which case the mapping is unchanged
1389		*/
1390		public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
1391		if (key == null || mappingFunction == null)
#	Line 1270 | Line 1471 | public class ConcurrentHashMapV8<K, V>
1471		* reflect any modifications subsequent to construction.
1472		*/
1473		public Set<K> keySet() {
1474	<	Set<K> ks = keySet;
1475	<	return (ks != null) ? ks : (keySet = new KeySet());
1474	>	KeySet<K,V> ks = keySet;
1475	>	return (ks != null) ? ks : (keySet = new KeySet<K,V>(this));
1476		}
1477
1478		/**
#	Line 1291 | Line 1492 | public class ConcurrentHashMapV8<K, V>
1492		* reflect any modifications subsequent to construction.
1493		*/
1494		public Collection<V> values() {
1495	<	Collection<V> vs = values;
1496	<	return (vs != null) ? vs : (values = new Values());
1495	>	Values<K,V> vs = values;
1496	>	return (vs != null) ? vs : (values = new Values<K,V>(this));
1497		}
1498
1499		/**
#	Line 1312 | Line 1513 | public class ConcurrentHashMapV8<K, V>
1513		* reflect any modifications subsequent to construction.
1514		*/
1515		public Set<Map.Entry<K,V>> entrySet() {
1516	<	Set<Map.Entry<K,V>> es = entrySet;
1517	<	return (es != null) ? es : (entrySet = new EntrySet());
1516	>	EntrySet<K,V> es = entrySet;
1517	>	return (es != null) ? es : (entrySet = new EntrySet<K,V>(this));
1518		}
1519
1520		/**
#	Line 1323 | Line 1524 | public class ConcurrentHashMapV8<K, V>
1524		* @see #keySet()
1525		*/
1526		public Enumeration<K> keys() {
1527	<	return new KeyIterator();
1527	>	return new KeyIterator<K,V>(this);
1528		}
1529
1530		/**
#	Line 1333 | Line 1534 | public class ConcurrentHashMapV8<K, V>
1534		* @see #values()
1535		*/
1536		public Enumeration<V> elements() {
1537	<	return new ValueIterator();
1537	>	return new ValueIterator<K,V>(this);
1538		}
1539
1540		/**
#	Line 1344 | Line 1545 | public class ConcurrentHashMapV8<K, V>
1545		* @return the hash code value for this map
1546		*/
1547		public int hashCode() {
1548	<	return new HashIterator().mapHashCode();
1548	>	int h = 0;
1549	>	InternalIterator it = new InternalIterator(table);
1550	>	while (it.next != null) {
1551	>	h += it.nextKey.hashCode() ^ it.nextVal.hashCode();
1552	>	it.advance();
1553	>	}
1554	>	return h;
1555		}
1556
1557		/**
#	Line 1359 | Line 1566 | public class ConcurrentHashMapV8<K, V>
1566		* @return a string representation of this map
1567		*/
1568		public String toString() {
1569	<	return new HashIterator().mapToString();
1569	>	InternalIterator it = new InternalIterator(table);
1570	>	StringBuilder sb = new StringBuilder();
1571	>	sb.append('{');
1572	>	if (it.next != null) {
1573	>	for (;;) {
1574	>	Object k = it.nextKey, v = it.nextVal;
1575	>	sb.append(k == this ? "(this Map)" : k);
1576	>	sb.append('=');
1577	>	sb.append(v == this ? "(this Map)" : v);
1578	>	it.advance();
1579	>	if (it.next == null)
1580	>	break;
1581	>	sb.append(',').append(' ');
1582	>	}
1583	>	}
1584	>	return sb.append('}').toString();
1585		}
1586
1587		/**
#	Line 1373 | Line 1595 | public class ConcurrentHashMapV8<K, V>
1595		* @return {@code true} if the specified object is equal to this map
1596		*/
1597		public boolean equals(Object o) {
1598	<	if (o == this)
1599	<	return true;
1600	<	if (!(o instanceof Map))
1601	<	return false;
1602	<	Map<?,?> m = (Map<?,?>) o;
1603	<	try {
1604	<	for (Map.Entry<K,V> e : this.entrySet())
1605	<	if (! e.getValue().equals(m.get(e.getKey())))
1598	>	if (o != this) {
1599	>	if (!(o instanceof Map))
1600	>	return false;
1601	>	Map<?,?> m = (Map<?,?>) o;
1602	>	InternalIterator it = new InternalIterator(table);
1603	>	while (it.next != null) {
1604	>	Object val = it.nextVal;
1605	>	Object v = m.get(it.nextKey);
1606	>	if (v == null || (v != val && !v.equals(val)))
1607		return false;
1608	+	it.advance();
1609	+	}
1610		for (Map.Entry<?,?> e : m.entrySet()) {
1611	<	Object k = e.getKey();
1612	<	Object v = e.getValue();
1613	<	if (k == null || v == null || !v.equals(get(k)))
1611	>	Object mk, mv, v;
1612	>	if ((mk = e.getKey()) == null ||
1613	>	(mv = e.getValue()) == null ||
1614	>	(v = internalGet(mk)) == null ||
1615	>	(mv != v && !mv.equals(v)))
1616		return false;
1617		}
1391	–	return true;
1392	–	} catch (ClassCastException unused) {
1393	–	return false;
1394	–	} catch (NullPointerException unused) {
1395	–	return false;
1618		}
1619	+	return true;
1620		}
1621
1622	+	/* ----------------Iterators -------------- */
1623	+
1624		/**
1625	<	* Custom Entry class used by EntryIterator.next(), that relays
1626	<	* setValue changes to the underlying map.
1625	>	* Base class for key, value, and entry iterators.  Adds a map
1626	>	* reference to InternalIterator to support Iterator.remove.
1627		*/
1628	<	final class WriteThroughEntry extends AbstractMap.SimpleEntry<K,V> {
1628	>	static abstract class ViewIterator<K,V> extends InternalIterator {
1629	>	final ConcurrentHashMapV8<K, V> map;
1630	>	ViewIterator(ConcurrentHashMapV8<K, V> map) {
1631	>	super(map.table);
1632	>	this.map = map;
1633	>	}
1634	>
1635	>	public final void remove() {
1636	>	if (last == null)
1637	>	throw new IllegalStateException();
1638	>	map.remove(last.key);
1639	>	last = null;
1640	>	}
1641	>
1642	>	public final boolean hasNext()         { return next != null; }
1643	>	public final boolean hasMoreElements() { return next != null; }
1644	>	}
1645	>
1646	>	static final class KeyIterator<K,V> extends ViewIterator<K,V>
1647	>	implements Iterator<K>, Enumeration<K> {
1648	>	KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
1649	>
1650		@SuppressWarnings("unchecked")
1651	<	WriteThroughEntry(Object k, Object v) {
1652	<	super((K)k, (V)v);
1651	>	public final K next() {
1652	>	if (next == null)
1653	>	throw new NoSuchElementException();
1654	>	Object k = nextKey;
1655	>	advance();
1656	>	return (K)k;
1657	>	}
1658	>
1659	>	public final K nextElement() { return next(); }
1660	>	}
1661	>
1662	>	static final class ValueIterator<K,V> extends ViewIterator<K,V>
1663	>	implements Iterator<V>, Enumeration<V> {
1664	>	ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
1665	>
1666	>	@SuppressWarnings("unchecked")
1667	>	public final V next() {
1668	>	if (next == null)
1669	>	throw new NoSuchElementException();
1670	>	Object v = nextVal;
1671	>	advance();
1672	>	return (V)v;
1673	>	}
1674	>
1675	>	public final V nextElement() { return next(); }
1676	>	}
1677	>
1678	>	static final class EntryIterator<K,V> extends ViewIterator<K,V>
1679	>	implements Iterator<Map.Entry<K,V>> {
1680	>	EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
1681	>
1682	>	@SuppressWarnings("unchecked")
1683	>	public final Map.Entry<K,V> next() {
1684	>	if (next == null)
1685	>	throw new NoSuchElementException();
1686	>	Object k = nextKey;
1687	>	Object v = nextVal;
1688	>	advance();
1689	>	return new WriteThroughEntry<K,V>((K)k, (V)v, map);
1690	>	}
1691	>	}
1692	>
1693	>	static final class SnapshotEntryIterator<K,V> extends ViewIterator<K,V>
1694	>	implements Iterator<Map.Entry<K,V>> {
1695	>	SnapshotEntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
1696	>
1697	>	@SuppressWarnings("unchecked")
1698	>	public final Map.Entry<K,V> next() {
1699	>	if (next == null)
1700	>	throw new NoSuchElementException();
1701	>	Object k = nextKey;
1702	>	Object v = nextVal;
1703	>	advance();
1704	>	return new SnapshotEntry<K,V>((K)k, (V)v);
1705	>	}
1706	>	}
1707	>
1708	>	/**
1709	>	* Base of writeThrough and Snapshot entry classes
1710	>	*/
1711	>	static abstract class MapEntry<K,V> implements Map.Entry<K, V> {
1712	>	final K key; // non-null
1713	>	V val;       // non-null
1714	>	MapEntry(K key, V val)        { this.key = key; this.val = val; }
1715	>	public final K getKey()       { return key; }
1716	>	public final V getValue()     { return val; }
1717	>	public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
1718	>	public final String toString(){ return key + "=" + val; }
1719	>
1720	>	public final boolean equals(Object o) {
1721	>	Object k, v; Map.Entry<?,?> e;
1722	>	return ((o instanceof Map.Entry) &&
1723	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
1724	>	(v = e.getValue()) != null &&
1725	>	(k == key || k.equals(key)) &&
1726	>	(v == val || v.equals(val)));
1727	>	}
1728	>
1729	>	public abstract V setValue(V value);
1730	>	}
1731	>
1732	>	/**
1733	>	* Entry used by EntryIterator.next(), that relays setValue
1734	>	* changes to the underlying map.
1735	>	*/
1736	>	static final class WriteThroughEntry<K,V> extends MapEntry<K,V>
1737	>	implements Map.Entry<K, V> {
1738	>	final ConcurrentHashMapV8<K, V> map;
1739	>	WriteThroughEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
1740	>	super(key, val);
1741	>	this.map = map;
1742		}
1743
1744		/**
#	Line 1415 | Line 1750 | public class ConcurrentHashMapV8<K, V>
1750		* removed in which case the put will re-establish). We do not
1751		* and cannot guarantee more.
1752		*/
1753	<	public V setValue(V value) {
1753	>	public final V setValue(V value) {
1754		if (value == null) throw new NullPointerException();
1755	<	V v = super.setValue(value);
1756	<	ConcurrentHashMapV8.this.put(getKey(), value);
1755	>	V v = val;
1756	>	val = value;
1757	>	map.put(key, value);
1758		return v;
1759		}
1760		}
1761
1762	<	final class KeyIterator extends HashIterator
1763	<	implements Iterator<K>, Enumeration<K> {
1764	<	@SuppressWarnings("unchecked")
1765	<	public final K next()        { return (K)super.nextKey(); }
1766	<	@SuppressWarnings("unchecked")
1767	<	public final K nextElement() { return (K)super.nextKey(); }
1762	>	/**
1763	>	* Internal version of entry, that doesn't write though changes
1764	>	*/
1765	>	static final class SnapshotEntry<K,V> extends MapEntry<K,V>
1766	>	implements Map.Entry<K, V> {
1767	>	SnapshotEntry(K key, V val) { super(key, val); }
1768	>	public final V setValue(V value) { // only locally update
1769	>	if (value == null) throw new NullPointerException();
1770	>	V v = val;
1771	>	val = value;
1772	>	return v;
1773	>	}
1774		}
1775
1776	<	final class ValueIterator extends HashIterator
1777	<	implements Iterator<V>, Enumeration<V> {
1778	<	@SuppressWarnings("unchecked")
1779	<	public final V next()        { return (V)super.nextValue(); }
1776	>	/* ----------------Views -------------- */
1777	>
1778	>	/**
1779	>	* Base class for views. This is done mainly to allow adding
1780	>	* customized parallel traversals (not yet implemented.)
1781	>	*/
1782	>	static abstract class MapView<K, V> {
1783	>	final ConcurrentHashMapV8<K, V> map;
1784	>	MapView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
1785	>	public final int size()                 { return map.size(); }
1786	>	public final boolean isEmpty()          { return map.isEmpty(); }
1787	>	public final void clear()               { map.clear(); }
1788	>
1789	>	// implementations below rely on concrete classes supplying these
1790	>	abstract Iterator<?> iter();
1791	>	abstract public boolean contains(Object o);
1792	>	abstract public boolean remove(Object o);
1793	>
1794	>	private static final String oomeMsg = "Required array size too large";
1795	>
1796	>	public final Object[] toArray() {
1797	>	long sz = map.longSize();
1798	>	if (sz > (long)(MAX_ARRAY_SIZE))
1799	>	throw new OutOfMemoryError(oomeMsg);
1800	>	int n = (int)sz;
1801	>	Object[] r = new Object[n];
1802	>	int i = 0;
1803	>	Iterator<?> it = iter();
1804	>	while (it.hasNext()) {
1805	>	if (i == n) {
1806	>	if (n >= MAX_ARRAY_SIZE)
1807	>	throw new OutOfMemoryError(oomeMsg);
1808	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
1809	>	n = MAX_ARRAY_SIZE;
1810	>	else
1811	>	n += (n >>> 1) + 1;
1812	>	r = Arrays.copyOf(r, n);
1813	>	}
1814	>	r[i++] = it.next();
1815	>	}
1816	>	return (i == n) ? r : Arrays.copyOf(r, i);
1817	>	}
1818	>
1819		@SuppressWarnings("unchecked")
1820	<	public final V nextElement() { return (V)super.nextValue(); }
1821	<	}
1820	>	public final <T> T[] toArray(T[] a) {
1821	>	long sz = map.longSize();
1822	>	if (sz > (long)(MAX_ARRAY_SIZE))
1823	>	throw new OutOfMemoryError(oomeMsg);
1824	>	int m = (int)sz;
1825	>	T[] r = (a.length >= m) ? a :
1826	>	(T[])java.lang.reflect.Array
1827	>	.newInstance(a.getClass().getComponentType(), m);
1828	>	int n = r.length;
1829	>	int i = 0;
1830	>	Iterator<?> it = iter();
1831	>	while (it.hasNext()) {
1832	>	if (i == n) {
1833	>	if (n >= MAX_ARRAY_SIZE)
1834	>	throw new OutOfMemoryError(oomeMsg);
1835	>	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
1836	>	n = MAX_ARRAY_SIZE;
1837	>	else
1838	>	n += (n >>> 1) + 1;
1839	>	r = Arrays.copyOf(r, n);
1840	>	}
1841	>	r[i++] = (T)it.next();
1842	>	}
1843	>	if (a == r && i < n) {
1844	>	r[i] = null; // null-terminate
1845	>	return r;
1846	>	}
1847	>	return (i == n) ? r : Arrays.copyOf(r, i);
1848	>	}
1849
1850	<	final class EntryIterator extends HashIterator
1851	<	implements Iterator<Entry<K,V>> {
1852	<	public final Map.Entry<K,V> next() { return super.nextEntry(); }
1853	<	}
1850	>	public final int hashCode() {
1851	>	int h = 0;
1852	>	for (Iterator<?> it = iter(); it.hasNext();)
1853	>	h += it.next().hashCode();
1854	>	return h;
1855	>	}
1856	>
1857	>	public final String toString() {
1858	>	StringBuilder sb = new StringBuilder();
1859	>	sb.append('[');
1860	>	Iterator<?> it = iter();
1861	>	if (it.hasNext()) {
1862	>	for (;;) {
1863	>	Object e = it.next();
1864	>	sb.append(e == this ? "(this Collection)" : e);
1865	>	if (!it.hasNext())
1866	>	break;
1867	>	sb.append(',').append(' ');
1868	>	}
1869	>	}
1870	>	return sb.append(']').toString();
1871	>	}
1872
1873	<	final class KeySet extends AbstractSet<K> {
1874	<	public int size() {
1875	<	return ConcurrentHashMapV8.this.size();
1873	>	public final boolean containsAll(Collection<?> c) {
1874	>	if (c != this) {
1875	>	for (Iterator<?> it = c.iterator(); it.hasNext();) {
1876	>	Object e = it.next();
1877	>	if (e == null || !contains(e))
1878	>	return false;
1879	>	}
1880	>	}
1881	>	return true;
1882	>	}
1883	>
1884	>	public final boolean removeAll(Collection c) {
1885	>	boolean modified = false;
1886	>	for (Iterator<?> it = iter(); it.hasNext();) {
1887	>	if (c.contains(it.next())) {
1888	>	it.remove();
1889	>	modified = true;
1890	>	}
1891	>	}
1892	>	return modified;
1893		}
1894	<	public boolean isEmpty() {
1895	<	return ConcurrentHashMapV8.this.isEmpty();
1894	>
1895	>	public final boolean retainAll(Collection<?> c) {
1896	>	boolean modified = false;
1897	>	for (Iterator<?> it = iter(); it.hasNext();) {
1898	>	if (!c.contains(it.next())) {
1899	>	it.remove();
1900	>	modified = true;
1901	>	}
1902	>	}
1903	>	return modified;
1904	>	}
1905	>
1906	>	}
1907	>
1908	>	static final class KeySet<K,V> extends MapView<K,V> implements Set<K> {
1909	>	KeySet(ConcurrentHashMapV8<K, V> map)   { super(map); }
1910	>	public final boolean contains(Object o) { return map.containsKey(o); }
1911	>	public final boolean remove(Object o)   { return map.remove(o) != null; }
1912	>
1913	>	public final Iterator<K> iterator() {
1914	>	return new KeyIterator<K,V>(map);
1915		}
1916	<	public void clear() {
1917	<	ConcurrentHashMapV8.this.clear();
1916	>	final Iterator<?> iter() {
1917	>	return new KeyIterator<K,V>(map);
1918		}
1919	<	public Iterator<K> iterator() {
1920	<	return new KeyIterator();
1919	>	public final boolean add(K e) {
1920	>	throw new UnsupportedOperationException();
1921		}
1922	<	public boolean contains(Object o) {
1923	<	return ConcurrentHashMapV8.this.containsKey(o);
1922	>	public final boolean addAll(Collection<? extends K> c) {
1923	>	throw new UnsupportedOperationException();
1924		}
1925	<	public boolean remove(Object o) {
1926	<	return ConcurrentHashMapV8.this.remove(o) != null;
1925	>	public boolean equals(Object o) {
1926	>	Set<?> c;
1927	>	return ((o instanceof Set) &&
1928	>	((c = (Set<?>)o) == this ||
1929	>	(containsAll(c) && c.containsAll(this))));
1930		}
1931		}
1932
1933	<	final class Values extends AbstractCollection<V> {
1934	<	public int size() {
1935	<	return ConcurrentHashMapV8.this.size();
1933	>	static final class Values<K,V> extends MapView<K,V>
1934	>	implements Collection<V>  {
1935	>	Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
1936	>	public final boolean contains(Object o) { return map.containsValue(o); }
1937	>
1938	>	public final boolean remove(Object o) {
1939	>	if (o != null) {
1940	>	Iterator<V> it = new ValueIterator<K,V>(map);
1941	>	while (it.hasNext()) {
1942	>	if (o.equals(it.next())) {
1943	>	it.remove();
1944	>	return true;
1945	>	}
1946	>	}
1947	>	}
1948	>	return false;
1949		}
1950	<	public boolean isEmpty() {
1951	<	return ConcurrentHashMapV8.this.isEmpty();
1950	>	public final Iterator<V> iterator() {
1951	>	return new ValueIterator<K,V>(map);
1952		}
1953	<	public void clear() {
1954	<	ConcurrentHashMapV8.this.clear();
1953	>	final Iterator<?> iter() {
1954	>	return new ValueIterator<K,V>(map);
1955		}
1956	<	public Iterator<V> iterator() {
1957	<	return new ValueIterator();
1956	>	public final boolean add(V e) {
1957	>	throw new UnsupportedOperationException();
1958		}
1959	<	public boolean contains(Object o) {
1960	<	return ConcurrentHashMapV8.this.containsValue(o);
1959	>	public final boolean addAll(Collection<? extends V> c) {
1960	>	throw new UnsupportedOperationException();
1961		}
1962		}
1963
1964	<	final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
1965	<	public int size() {
1966	<	return ConcurrentHashMapV8.this.size();
1964	>	static final class EntrySet<K,V>  extends MapView<K,V>
1965	>	implements Set<Map.Entry<K,V>> {
1966	>	EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
1967	>
1968	>	public final boolean contains(Object o) {
1969	>	Object k, v, r; Map.Entry<?,?> e;
1970	>	return ((o instanceof Map.Entry) &&
1971	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
1972	>	(r = map.get(k)) != null &&
1973	>	(v = e.getValue()) != null &&
1974	>	(v == r || v.equals(r)));
1975		}
1976	<	public boolean isEmpty() {
1977	<	return ConcurrentHashMapV8.this.isEmpty();
1976	>
1977	>	public final boolean remove(Object o) {
1978	>	Object k, v; Map.Entry<?,?> e;
1979	>	return ((o instanceof Map.Entry) &&
1980	>	(k = (e = (Map.Entry<?,?>)o).getKey()) != null &&
1981	>	(v = e.getValue()) != null &&
1982	>	map.remove(k, v));
1983		}
1984	<	public void clear() {
1985	<	ConcurrentHashMapV8.this.clear();
1984	>
1985	>	public final Iterator<Map.Entry<K,V>> iterator() {
1986	>	return new EntryIterator<K,V>(map);
1987		}
1988	<	public Iterator<Map.Entry<K,V>> iterator() {
1989	<	return new EntryIterator();
1988	>	final Iterator<?> iter() {
1989	>	return new SnapshotEntryIterator<K,V>(map);
1990		}
1991	<	public boolean contains(Object o) {
1992	<	if (!(o instanceof Map.Entry))
1501	<	return false;
1502	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
1503	<	V v = ConcurrentHashMapV8.this.get(e.getKey());
1504	<	return v != null && v.equals(e.getValue());
1991	>	public final boolean add(Entry<K,V> e) {
1992	>	throw new UnsupportedOperationException();
1993		}
1994	<	public boolean remove(Object o) {
1995	<	if (!(o instanceof Map.Entry))
1996	<	return false;
1997	<	Map.Entry<?,?> e = (Map.Entry<?,?>)o;
1998	<	return ConcurrentHashMapV8.this.remove(e.getKey(), e.getValue());
1994	>	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
1995	>	throw new UnsupportedOperationException();
1996	>	}
1997	>	public boolean equals(Object o) {
1998	>	Set<?> c;
1999	>	return ((o instanceof Set) &&
2000	>	((c = (Set<?>)o) == this ||
2001	>	(containsAll(c) && c.containsAll(this))));
2002		}
2003		}
2004
2005		/* ---------------- Serialization Support -------------- */
2006
2007		/**
2008	<	* Helper class used in previous version, declared for the sake of
2009	<	* serialization compatibility
2008	>	* Stripped-down version of helper class used in previous version,
2009	>	* declared for the sake of serialization compatibility
2010		*/
2011	<	static class Segment<K,V> extends java.util.concurrent.locks.ReentrantLock
1521	<	implements Serializable {
2011	>	static class Segment<K,V> implements Serializable {
2012		private static final long serialVersionUID = 2249069246763182397L;
2013		final float loadFactor;
2014		Segment(float lf) { this.loadFactor = lf; }
#	Line 1540 | Line 2030 | public class ConcurrentHashMapV8<K, V>
2030		segments = (Segment<K,V>[])
2031		new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
2032		for (int i = 0; i < segments.length; ++i)
2033	<	segments[i] = new Segment<K,V>(loadFactor);
2033	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
2034		}
2035		s.defaultWriteObject();
2036	<	new HashIterator().writeEntries(s);
2036	>	InternalIterator it = new InternalIterator(table);
2037	>	while (it.next != null) {
2038	>	s.writeObject(it.nextKey);
2039	>	s.writeObject(it.nextVal);
2040	>	it.advance();
2041	>	}
2042		s.writeObject(null);
2043		s.writeObject(null);
2044		segments = null; // throw away
2045		}
2046
2047		/**
2048	<	* Reconstitutes the  instance from a
1554	<	* stream (i.e., deserializes it).
2048	>	* Reconstitutes the instance from a stream (that is, deserializes it).
2049		* @param s the stream
2050		*/
2051		@SuppressWarnings("unchecked")
2052		private void readObject(java.io.ObjectInputStream s)
2053		throws java.io.IOException, ClassNotFoundException {
2054		s.defaultReadObject();
1561	–	// find load factor in a segment, if one exists
1562	–	if (segments != null && segments.length != 0)
1563	–	this.loadFactor = segments[0].loadFactor;
1564	–	else
1565	–	this.loadFactor = DEFAULT_LOAD_FACTOR;
1566	–	this.initCap = DEFAULT_CAPACITY;
1567	–	LongAdder ct = new LongAdder(); // force final field write
1568	–	UNSAFE.putObjectVolatile(this, counterOffset, ct);
2055		this.segments = null; // unneeded
2056	+	// initialize transient final field
2057	+	UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
2058
2059	<	// Read the keys and values, and put the mappings in the table
2059	>	// Create all nodes, then place in table once size is known
2060	>	long size = 0L;
2061	>	Node p = null;
2062		for (;;) {
2063	<	K key = (K) s.readObject();
2064	<	V value = (V) s.readObject();
2065	<	if (key == null)
2063	>	K k = (K) s.readObject();
2064	>	V v = (V) s.readObject();
2065	>	if (k != null && v != null) {
2066	>	p = new Node(spread(k.hashCode()), k, v, p);
2067	>	++size;
2068	>	}
2069	>	else
2070		break;
2071	<	put(key, value);
2071	>	}
2072	>	if (p != null) {
2073	>	boolean init = false;
2074	>	int n;
2075	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
2076	>	n = MAXIMUM_CAPACITY;
2077	>	else {
2078	>	int sz = (int)size;
2079	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
2080	>	}
2081	>	int sc = sizeCtl;
2082	>	if (n > sc &&
2083	>	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
2084	>	try {
2085	>	if (table == null) {
2086	>	init = true;
2087	>	Node[] tab = new Node[n];
2088	>	int mask = n - 1;
2089	>	while (p != null) {
2090	>	int j = p.hash & mask;
2091	>	Node next = p.next;
2092	>	p.next = tabAt(tab, j);
2093	>	setTabAt(tab, j, p);
2094	>	p = next;
2095	>	}
2096	>	table = tab;
2097	>	counter.add(size);
2098	>	sc = n - (n >>> 2) - 1;
2099	>	}
2100	>	} finally {
2101	>	sizeCtl = sc;
2102	>	}
2103	>	}
2104	>	if (!init) { // Can only happen if unsafely published.
2105	>	while (p != null) {
2106	>	internalPut(p.key, p.val, true);
2107	>	p = p.next;
2108	>	}
2109	>	}
2110		}
2111		}
2112
2113		// Unsafe mechanics
2114		private static final sun.misc.Unsafe UNSAFE;
2115		private static final long counterOffset;
2116	<	private static final long resizingOffset;
2116	>	private static final long sizeCtlOffset;
2117		private static final long ABASE;
2118		private static final int ASHIFT;
2119
#	Line 1592 | Line 2124 | public class ConcurrentHashMapV8<K, V>
2124		Class<?> k = ConcurrentHashMapV8.class;
2125		counterOffset = UNSAFE.objectFieldOffset
2126		(k.getDeclaredField("counter"));
2127	<	resizingOffset = UNSAFE.objectFieldOffset
2128	<	(k.getDeclaredField("resizing"));
2127	>	sizeCtlOffset = UNSAFE.objectFieldOffset
2128	>	(k.getDeclaredField("sizeCtl"));
2129		Class<?> sc = Node[].class;
2130		ABASE = UNSAFE.arrayBaseOffset(sc);
2131		ss = UNSAFE.arrayIndexScale(sc);

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