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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.14 by dl, Tue Sep 6 00:26:27 2011 UTC vs.
Revision 1.37 by dl, Sun Mar 4 20:34:27 2012 UTC

#	Line 6 | Line 6
6
7		package jsr166e;
8		import jsr166e.LongAdder;
9	+	import java.util.Arrays;
10		import java.util.Map;
11		import java.util.Set;
12		import java.util.Collection;
#	Line 19 | Line 20 | import java.util.Enumeration;
20		import java.util.ConcurrentModificationException;
21		import java.util.NoSuchElementException;
22		import java.util.concurrent.ConcurrentMap;
23	+	import java.util.concurrent.ThreadLocalRandom;
24	+	import java.util.concurrent.locks.LockSupport;
25		import java.io.Serializable;
26
27		/**
#	Line 49 | Line 52 | import java.io.Serializable;
52		* are typically useful only when a map is not undergoing concurrent
53		* updates in other threads.  Otherwise the results of these methods
54		* reflect transient states that may be adequate for monitoring
55	<	* purposes, but not for program control.
55	>	* or estimation purposes, but not for program control.
56		*
57	<	* <p> Resizing this or any other kind of hash table is a relatively
58	<	* slow operation, so, when possible, it is a good idea to provide
59	<	* estimates of expected table sizes in constructors. Also, for
60	<	* compatibility with previous versions of this class, constructors
61	<	* may optionally specify an expected {@code concurrencyLevel} as an
62	<	* additional hint for internal sizing.
57	>	* <p> The table is dynamically expanded when there are too many
58	>	* collisions (i.e., keys that have distinct hash codes but fall into
59	>	* the same slot modulo the table size), with the expected average
60	>	* effect of maintaining roughly two bins per mapping (corresponding
61	>	* to a 0.75 load factor threshold for resizing). There may be much
62	>	* variance around this average as mappings are added and removed, but
63	>	* overall, this maintains a commonly accepted time/space tradeoff for
64	>	* hash tables.  However, resizing this or any other kind of hash
65	>	* table may be a relatively slow operation. When possible, it is a
66	>	* good idea to provide a size estimate as an optional {@code
67	>	* initialCapacity} constructor argument. An additional optional
68	>	* {@code loadFactor} constructor argument provides a further means of
69	>	* customizing initial table capacity by specifying the table density
70	>	* to be used in calculating the amount of space to allocate for the
71	>	* given number of elements.  Also, for compatibility with previous
72	>	* versions of this class, constructors may optionally specify an
73	>	* expected {@code concurrencyLevel} as an additional hint for
74	>	* internal sizing.  Note that using many keys with exactly the same
75	>	* {@code hashCode()} is a sure way to slow down performance of any
76	>	* hash table.
77		*
78		* <p>This class and its views and iterators implement all of the
79		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
#	Line 82 | Line 99 | public class ConcurrentHashMapV8<K, V>
99		private static final long serialVersionUID = 7249069246763182397L;
100
101		/**
102	<	* A function computing a mapping from the given key to a value,
103	<	* or {@code null} if there is no mapping. This is a place-holder
87	<	* for an upcoming JDK8 interface.
102	>	* A function computing a mapping from the given key to a value.
103	>	* This is a place-holder for an upcoming JDK8 interface.
104		*/
105		public static interface MappingFunction<K, V> {
106		/**
107	<	* Returns a value for the given key, or null if there is no
92	<	* mapping. If this function throws an (unchecked) exception,
93	<	* the exception is rethrown to its caller, and no mapping is
94	<	* recorded.  Because this function is invoked within
95	<	* atomicity control, the computation should be short and
96	<	* simple. The most common usage is to construct a new object
97	<	* serving as an initial mapped value.
107	>	* Returns a non-null value for the given key.
108		*
109		* @param key the (non-null) key
110	<	* @return a value, or null if none
110	>	* @return a non-null value
111		*/
112		V map(K key);
113		}
114
115	+	/**
116	+	* A function computing a new mapping given a key and its current
117	+	* mapped value (or {@code null} if there is no current
118	+	* mapping). This is a place-holder for an upcoming JDK8
119	+	* interface.
120	+	*/
121	+	public static interface RemappingFunction<K, V> {
122	+	/**
123	+	* Returns a new value given a key and its current value.
124	+	*
125	+	* @param key the (non-null) key
126	+	* @param value the current value, or null if there is no mapping
127	+	* @return a non-null value
128	+	*/
129	+	V remap(K key, V value);
130	+	}
131	+
132		/*
133		* Overview:
134		*
135		* The primary design goal of this hash table is to maintain
136		* concurrent readability (typically method get(), but also
137		* iterators and related methods) while minimizing update
138	<	* contention.
138	>	* contention. Secondary goals are to keep space consumption about
139	>	* the same or better than java.util.HashMap, and to support high
140	>	* initial insertion rates on an empty table by many threads.
141		*
142		* Each key-value mapping is held in a Node.  Because Node fields
143		* can contain special values, they are defined using plain Object
#	Line 116 | Line 145 | public class ConcurrentHashMapV8<K, V>
145		* work off Object types. And similarly, so do the internal
146		* methods of auxiliary iterator and view classes.  All public
147		* generic typed methods relay in/out of these internal methods,
148	<	* supplying null-checks and casts as needed.
148	>	* supplying null-checks and casts as needed. This also allows
149	>	* many of the public methods to be factored into a smaller number
150	>	* of internal methods (although sadly not so for the five
151	>	* sprawling variants of put-related operations).
152		*
153		* The table is lazily initialized to a power-of-two size upon the
154		* first insertion.  Each bin in the table contains a list of
155	<	* Nodes (most often, zero or one Node).  Table accesses require
156	<	* volatile/atomic reads, writes, and CASes.  Because there is no
157	<	* other way to arrange this without adding further indirections,
158	<	* we use intrinsics (sun.misc.Unsafe) operations.  The lists of
159	<	* nodes within bins are always accurately traversable under
160	<	* volatile reads, so long as lookups check hash code and
161	<	* non-nullness of value before checking key equality. (All valid
162	<	* hash codes are nonnegative. Negative values are reserved for
163	<	* special forwarding nodes; see below.)
155	>	* Nodes (most often, the list has only zero or one Node).  Table
156	>	* accesses require volatile/atomic reads, writes, and CASes.
157	>	* Because there is no other way to arrange this without adding
158	>	* further indirections, we use intrinsics (sun.misc.Unsafe)
159	>	* operations.  The lists of nodes within bins are always
160	>	* accurately traversable under volatile reads, so long as lookups
161	>	* check hash code and non-nullness of value before checking key
162	>	* equality.
163	>	*
164	>	* We use the top two bits of Node hash fields for control
165	>	* purposes -- they are available anyway because of addressing
166	>	* constraints.  As explained further below, these top bits are
167	>	* used as follows:
168	>	*  00 - Normal
169	>	*  01 - Locked
170	>	*  11 - Locked and may have a thread waiting for lock
171	>	*  10 - Node is a forwarding node
172	>	*
173	>	* The lower 30 bits of each Node's hash field contain a
174	>	* transformation (for better randomization -- method "spread") of
175	>	* the key's hash code, except for forwarding nodes, for which the
176	>	* lower bits are zero (and so always have hash field == MOVED).
177		*
178	<	* Insertion (via put or putIfAbsent) of the first node in an
178	>	* Insertion (via put or its variants) of the first node in an
179		* empty bin is performed by just CASing it to the bin.  This is
180	<	* on average by far the most common case for put operations.
181	<	* Other update operations (insert, delete, and replace) require
182	<	* locks.  We do not want to waste the space required to associate
183	<	* a distinct lock object with each bin, so instead use the first
184	<	* node of a bin list itself as a lock, using plain "synchronized"
185	<	* locks. These save space and we can live with block-structured
186	<	* lock/unlock operations. Using the first node of a list as a
187	<	* lock does not by itself suffice though: When a node is locked,
188	<	* any update must first validate that it is still the first node,
189	<	* and retry if not. Because new nodes are always appended to
190	<	* lists, once a node is first in a bin, it remains first until
191	<	* deleted or the bin becomes invalidated.  However, operations
192	<	* that only conditionally update can and sometimes do inspect
193	<	* nodes until the point of update. This is a converse of sorts to
194	<	* the lazy locking technique described by Herlihy & Shavit.
180	>	* by far the most common case for put operations.  Other update
181	>	* operations (insert, delete, and replace) require locks.  We do
182	>	* not want to waste the space required to associate a distinct
183	>	* lock object with each bin, so instead use the first node of a
184	>	* bin list itself as a lock. Blocking support for these locks
185	>	* relies on the builtin "synchronized" monitors.  However, we
186	>	* also need a tryLock construction, so we overlay these by using
187	>	* bits of the Node hash field for lock control (see above), and
188	>	* so normally use builtin monitors only for blocking and
189	>	* signalling using wait/notifyAll constructions. See
190	>	* Node.tryAwaitLock.
191	>	*
192	>	* Using the first node of a list as a lock does not by itself
193	>	* suffice though: When a node is locked, any update must first
194	>	* validate that it is still the first node after locking it, and
195	>	* retry if not. Because new nodes are always appended to lists,
196	>	* once a node is first in a bin, it remains first until deleted
197	>	* or the bin becomes invalidated (upon resizing).  However,
198	>	* operations that only conditionally update may inspect nodes
199	>	* until the point of update. This is a converse of sorts to the
200	>	* lazy locking technique described by Herlihy & Shavit.
201		*
202	<	* The main disadvantage of this approach is that most update
202	>	* The main disadvantage of per-bin locks is that other update
203		* operations on other nodes in a bin list protected by the same
204		* lock can stall, for example when user equals() or mapping
205		* functions take a long time.  However, statistically, this is
#	Line 156 | Line 207 | public class ConcurrentHashMapV8<K, V>
207		* of alternatives: Under random hash codes, the frequency of
208		* nodes in bins follows a Poisson distribution
209		* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
210	<	* parameter of 0.5 on average under the default loadFactor of
211	<	* 0.75. The expected number of locks covering different elements
212	<	* (i.e., bins with 2 or more nodes) is approximately 10% at
213	<	* steady state.  Lock contention probability for two threads
214	<	* accessing distinct elements is roughly 1 / (8 * #elements).
215	<	* Function "spread" performs hashCode randomization that improves
216	<	* the likelihood that these assumptions hold unless users define
217	<	* exactly the same value for too many hashCodes.
218	<	*
219	<	* The table is resized when occupancy exceeds a threshold.  Only
220	<	* a single thread performs the resize (using field "resizing", to
221	<	* arrange exclusion), but the table otherwise remains usable for
222	<	* reads and updates. Resizing proceeds by transferring bins, one
223	<	* by one, from the table to the next table.  Upon transfer, the
224	<	* old table bin contains only a special forwarding node (with
225	<	* negative hash field) that contains the next table as its
226	<	* key. On encountering a forwarding node, access and update
227	<	* operations restart, using the new table. To ensure concurrent
228	<	* readability of traversals, transfers must proceed from the last
229	<	* bin (table.length - 1) up towards the first.  Upon seeing a
230	<	* forwarding node, traversals (see class InternalIterator)
231	<	* arrange to move to the new table for the rest of the traversal
232	<	* without revisiting nodes.  This constrains bin transfers to a
233	<	* particular order, and so can block indefinitely waiting for the
234	<	* next lock, and other threads cannot help with the transfer.
235	<	* However, expected stalls are infrequent enough to not warrant
236	<	* the additional overhead of access and iteration schemes that
237	<	* could admit out-of-order or concurrent bin transfers.
210	>	* parameter of about 0.5 on average, given the resizing threshold
211	>	* of 0.75, although with a large variance because of resizing
212	>	* granularity. Ignoring variance, the expected occurrences of
213	>	* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
214	>	* first few values are:
215	>	*
216	>	* 0:    0.607
217	>	* 1:    0.303
218	>	* 2:    0.076
219	>	* 3:    0.012
220	>	* more: 0.002
221	>	*
222	>	* Lock contention probability for two threads accessing distinct
223	>	* elements is roughly 1 / (8 * #elements).  Function "spread"
224	>	* performs hashCode randomization that improves the likelihood
225	>	* that these assumptions hold unless users define exactly the
226	>	* same value for too many hashCodes.
227	>	*
228	>	* The table is resized when occupancy exceeds an occupancy
229	>	* threshold (nominally, 0.75, but see below).  Only a single
230	>	* thread performs the resize (using field "sizeCtl", to arrange
231	>	* exclusion), but the table otherwise remains usable for reads
232	>	* and updates. Resizing proceeds by transferring bins, one by
233	>	* one, from the table to the next table.  Because we are using
234	>	* power-of-two expansion, the elements from each bin must either
235	>	* stay at same index, or move with a power of two offset. We
236	>	* eliminate unnecessary node creation by catching cases where old
237	>	* nodes can be reused because their next fields won't change.  On
238	>	* average, only about one-sixth of them need cloning when a table
239	>	* doubles. The nodes they replace will be garbage collectable as
240	>	* soon as they are no longer referenced by any reader thread that
241	>	* may be in the midst of concurrently traversing table.  Upon
242	>	* transfer, the old table bin contains only a special forwarding
243	>	* node (with hash field "MOVED") that contains the next table as
244	>	* its key. On encountering a forwarding node, access and update
245	>	* operations restart, using the new table.
246	>	*
247	>	* Each bin transfer requires its bin lock. However, unlike other
248	>	* cases, a transfer can skip a bin if it fails to acquire its
249	>	* lock, and revisit it later. Method rebuild maintains a buffer
250	>	* of TRANSFER_BUFFER_SIZE bins that have been skipped because of
251	>	* failure to acquire a lock, and blocks only if none are
252	>	* available (i.e., only very rarely).  The transfer operation
253	>	* must also ensure that all accessible bins in both the old and
254	>	* new table are usable by any traversal.  When there are no lock
255	>	* acquisition failures, this is arranged simply by proceeding
256	>	* from the last bin (table.length - 1) up towards the first.
257	>	* Upon seeing a forwarding node, traversals (see class
258	>	* InternalIterator) arrange to move to the new table without
259	>	* revisiting nodes.  However, when any node is skipped during a
260	>	* transfer, all earlier table bins may have become visible, so
261	>	* are initialized with a reverse-forwarding node back to the old
262	>	* table until the new ones are established. (This sometimes
263	>	* requires transiently locking a forwarding node, which is
264	>	* possible under the above encoding.) These more expensive
265	>	* mechanics trigger only when necessary.
266		*
267	<	* This traversal scheme also applies to partial traversals of
267	>	* The traversal scheme also applies to partial traversals of
268		* ranges of bins (via an alternate InternalIterator constructor)
269		* to support partitioned aggregate operations (that are not
270		* otherwise implemented yet).  Also, read-only operations give up
#	Line 196 | Line 275 | public class ConcurrentHashMapV8<K, V>
275		* Lazy table initialization minimizes footprint until first use,
276		* and also avoids resizings when the first operation is from a
277		* putAll, constructor with map argument, or deserialization.
278	<	* These cases attempt to override the targetCapacity used in
279	<	* growTable (which may harmlessly fail to take effect in cases of
201	<	* races with other ongoing resizings).
278	>	* These cases attempt to override the initial capacity settings,
279	>	* but harmlessly fail to take effect in cases of races.
280		*
281		* The element count is maintained using a LongAdder, which avoids
282		* contention on updates but can encounter cache thrashing if read
283		* too frequently during concurrent access. To avoid reading so
284	<	* often, resizing is normally attempted only upon adding to a bin
285	<	* already holding two or more nodes. Under the default load
286	<	* factor and uniform hash distributions, the probability of this
287	<	* occurring at threshold is around 13%, meaning that only about 1
288	<	* in 8 puts check threshold (and after resizing, many fewer do
289	<	* so). But this approximation has high variance for small table
290	<	* sizes, so we check on any collision for sizes <= 64.  Further,
291	<	* to increase the probability that a resize occurs soon enough,
292	<	* we offset the threshold (see THRESHOLD_OFFSET) by the expected
293	<	* number of puts between checks. This is currently set to 8, in
294	<	* accord with the default load factor. In practice, this default
217	<	* is rarely overridden, and in any case is close enough to other
218	<	* plausible values not to waste dynamic probability computation
219	<	* for the sake of more precision.
284	>	* often, resizing is attempted either when a bin lock is
285	>	* contended, or upon adding to a bin already holding two or more
286	>	* nodes (checked before adding in the xIfAbsent methods, after
287	>	* adding in others). Under uniform hash distributions, the
288	>	* probability of this occurring at threshold is around 13%,
289	>	* meaning that only about 1 in 8 puts check threshold (and after
290	>	* resizing, many fewer do so). But this approximation has high
291	>	* variance for small table sizes, so we check on any collision
292	>	* for sizes <= 64. The bulk putAll operation further reduces
293	>	* contention by only committing count updates upon these size
294	>	* checks.
295		*
296		* Maintaining API and serialization compatibility with previous
297		* versions of this class introduces several oddities. Mainly: We
298		* leave untouched but unused constructor arguments refering to
299	<	* concurrencyLevel. We also declare an unused "Segment" class
300	<	* that is instantiated in minimal form only when serializing.
299	>	* concurrencyLevel. We accept a loadFactor constructor argument,
300	>	* but apply it only to initial table capacity (which is the only
301	>	* time that we can guarantee to honor it.) We also declare an
302	>	* unused "Segment" class that is instantiated in minimal form
303	>	* only when serializing.
304		*/
305
306		/* ---------------- Constants -------------- */
307
308		/**
309	<	* The largest allowed table capacity.  Must be a power of 2, at
310	<	* most 1<<30 to stay within Java array size limits.
309	>	* The largest possible table capacity.  This value must be
310	>	* exactly 1<<30 to stay within Java array allocation and indexing
311	>	* bounds for power of two table sizes, and is further required
312	>	* because the top two bits of 32bit hash fields are used for
313	>	* control purposes.
314		*/
315		private static final int MAXIMUM_CAPACITY = 1 << 30;
316
#	Line 240 | Line 321 | public class ConcurrentHashMapV8<K, V>
321		private static final int DEFAULT_CAPACITY = 16;
322
323		/**
324	<	* The default load factor for this table, used when not otherwise
325	<	* specified in a constructor.
324	>	* The largest possible (non-power of two) array size.
325	>	* Needed by toArray and related methods.
326		*/
327	<	private static final float DEFAULT_LOAD_FACTOR = 0.75f;
327	>	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
328
329		/**
330	<	* The default concurrency level for this table. Unused, but
330	>	* The default concurrency level for this table. Unused but
331		* defined for compatibility with previous versions of this class.
332		*/
333		private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
334
335		/**
336	<	* The count value to offset thresholds to compensate for checking
337	<	* for the need to resize only when inserting into bins with two
338	<	* or more elements. See above for explanation.
336	>	* The load factor for this table. Overrides of this value in
337	>	* constructors affect only the initial table capacity.  The
338	>	* actual floating point value isn't normally used -- it is
339	>	* simpler to use expressions such as {@code n - (n >>> 2)} for
340	>	* the associated resizing threshold.
341		*/
342	<	private static final int THRESHOLD_OFFSET = 8;
260	<
261	<	/* ---------------- Nodes -------------- */
342	>	private static final float LOAD_FACTOR = 0.75f;
343
344		/**
345	<	* Key-value entry. Note that this is never exported out as a
346	<	* user-visible Map.Entry. Nodes with a negative hash field are
347	<	* special, and do not contain user keys or values.  Otherwise,
267	<	* keys are never null, and null val fields indicate that a node
268	<	* is in the process of being deleted or created. For purposes of
269	<	* read-only, access, a key may be read before a val, but can only
270	<	* be used after checking val.  (For an update operation, when a
271	<	* lock is held on a node, order doesn't matter.)
345	>	* The buffer size for skipped bins during transfers. The
346	>	* value is arbitrary but should be large enough to avoid
347	>	* most locking stalls during resizes.
348		*/
349	<	static final class Node {
274	<	final int hash;
275	<	final Object key;
276	<	volatile Object val;
277	<	volatile Node next;
349	>	private static final int TRANSFER_BUFFER_SIZE = 32;
350
351	<	Node(int hash, Object key, Object val, Node next) {
352	<	this.hash = hash;
353	<	this.key = key;
282	<	this.val = val;
283	<	this.next = next;
284	<	}
285	<	}
286	<
287	<	/**
288	<	* Sign bit of node hash value indicating to use table in node.key.
351	>	/*
352	>	* Encodings for special uses of Node hash fields. See above for
353	>	* explanation.
354		*/
355	<	private static final int SIGN_BIT = 0x80000000;
355	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
356	>	static final int LOCKED    = 0x40000000; // set/tested only as a bit
357	>	static final int WAITING   = 0xc0000000; // both bits set/tested together
358	>	static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
359
360		/* ---------------- Fields -------------- */
361
#	Line 297 | Line 365 | public class ConcurrentHashMapV8<K, V>
365		*/
366		transient volatile Node[] table;
367
368	<	/** The counter maintaining number of elements. */
368	>	/**
369	>	* The counter maintaining number of elements.
370	>	*/
371		private transient final LongAdder counter;
372	<	/** Nonzero when table is being initialized or resized. Updated via CAS. */
373	<	private transient volatile int resizing;
374	<	/** The next element count value upon which to resize the table. */
375	<	private transient int threshold;
376	<	/** The target capacity; volatile to cover initialization races. */
377	<	private transient volatile int targetCapacity;
378	<	/** The target load factor for the table */
379	<	private transient final float loadFactor;
372	>
373	>	/**
374	>	* Table initialization and resizing control.  When negative, the
375	>	* table is being initialized or resized. Otherwise, when table is
376	>	* null, holds the initial table size to use upon creation, or 0
377	>	* for default. After initialization, holds the next element count
378	>	* value upon which to resize the table.
379	>	*/
380	>	private transient volatile int sizeCtl;
381
382		// views
383		private transient KeySet<K,V> keySet;
#	Line 316 | Line 387 | public class ConcurrentHashMapV8<K, V>
387		/** For serialization compatibility. Null unless serialized; see below */
388		private Segment<K,V>[] segments;
389
390	+	/* ---------------- Nodes -------------- */
391	+
392	+	/**
393	+	* Key-value entry. Note that this is never exported out as a
394	+	* user-visible Map.Entry (see WriteThroughEntry and SnapshotEntry
395	+	* below). Nodes with a hash field of MOVED are special, and do
396	+	* not contain user keys or values.  Otherwise, keys are never
397	+	* null, and null val fields indicate that a node is in the
398	+	* process of being deleted or created. For purposes of read-only
399	+	* access, a key may be read before a val, but can only be used
400	+	* after checking val to be non-null.
401	+	*/
402	+	static final class Node {
403	+	volatile int hash;
404	+	final Object key;
405	+	volatile Object val;
406	+	volatile Node next;
407	+
408	+	Node(int hash, Object key, Object val, Node next) {
409	+	this.hash = hash;
410	+	this.key = key;
411	+	this.val = val;
412	+	this.next = next;
413	+	}
414	+
415	+	/** CompareAndSet the hash field */
416	+	final boolean casHash(int cmp, int val) {
417	+	return UNSAFE.compareAndSwapInt(this, hashOffset, cmp, val);
418	+	}
419	+
420	+	/** The number of spins before blocking for a lock */
421	+	static final int MAX_SPINS =
422	+	Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1;
423	+
424	+	/**
425	+	* Spins a while if LOCKED bit set and this node is the first
426	+	* of its bin, and then sets WAITING bits on hash field and
427	+	* blocks (once) if they are still set.  It is OK for this
428	+	* method to return even if lock is not available upon exit,
429	+	* which enables these simple single-wait mechanics.
430	+	*
431	+	* The corresponding signalling operation is performed within
432	+	* callers: Upon detecting that WAITING has been set when
433	+	* unlocking lock (via a failed CAS from non-waiting LOCKED
434	+	* state), unlockers acquire the sync lock and perform a
435	+	* notifyAll.
436	+	*/
437	+	final void tryAwaitLock(Node[] tab, int i) {
438	+	if (tab != null && i >= 0 && i < tab.length) { // bounds check
439	+	int r = ThreadLocalRandom.current().nextInt(); // randomize spins
440	+	int spins = MAX_SPINS, h;
441	+	while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
442	+	if (spins >= 0) {
443	+	r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
444	+	if (r >= 0 && --spins == 0)
445	+	Thread.yield();  // yield before block
446	+	}
447	+	else if (casHash(h, h | WAITING)) {
448	+	synchronized (this) {
449	+	if (tabAt(tab, i) == this &&
450	+	(hash & WAITING) == WAITING) {
451	+	try {
452	+	wait();
453	+	} catch (InterruptedException ie) {
454	+	Thread.currentThread().interrupt();
455	+	}
456	+	}
457	+	else
458	+	notifyAll(); // possibly won race vs signaller
459	+	}
460	+	break;
461	+	}
462	+	}
463	+	}
464	+	}
465	+
466	+	// Unsafe mechanics for casHash
467	+	private static final sun.misc.Unsafe UNSAFE;
468	+	private static final long hashOffset;
469	+
470	+	static {
471	+	try {
472	+	UNSAFE = getUnsafe();
473	+	Class<?> k = Node.class;
474	+	hashOffset = UNSAFE.objectFieldOffset
475	+	(k.getDeclaredField("hash"));
476	+	} catch (Exception e) {
477	+	throw new Error(e);
478	+	}
479	+	}
480	+	}
481	+
482		/* ---------------- Table element access -------------- */
483
484		/*
#	Line 342 | Line 505 | public class ConcurrentHashMapV8<K, V>
505		UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
506		}
507
345	–	/* ----------------Table Initialization and Resizing -------------- */
346	–
347	–	/**
348	–	* Returns a power of two table size for the given desired capacity.
349	–	* See Hackers Delight, sec 3.2
350	–	*/
351	–	private static final int tableSizeFor(int c) {
352	–	int n = c - 1;
353	–	n |= n >>> 1;
354	–	n |= n >>> 2;
355	–	n |= n >>> 4;
356	–	n |= n >>> 8;
357	–	n |= n >>> 16;
358	–	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
359	–	}
360	–
361	–	/**
362	–	* If not already resizing, initializes or creates next table and
363	–	* transfers bins. Initial table size uses the capacity recorded
364	–	* in targetCapacity.  Rechecks occupancy after a transfer to see
365	–	* if another resize is already needed because resizings are
366	–	* lagging additions.
367	–	*
368	–	* @return current table
369	–	*/
370	–	private final Node[] growTable() {
371	–	if (resizing == 0 &&
372	–	UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
373	–	try {
374	–	for (;;) {
375	–	Node[] tab = table;
376	–	int n, c;
377	–	if (tab == null)
378	–	n = (c = targetCapacity) > 0 ? c : DEFAULT_CAPACITY;
379	–	else if ((n = tab.length) < MAXIMUM_CAPACITY &&
380	–	counter.sum() >= threshold)
381	–	n <<= 1;
382	–	else
383	–	break;
384	–	Node[] nextTab = new Node[n];
385	–	threshold = (int)(n * loadFactor) - THRESHOLD_OFFSET;
386	–	if (tab != null)
387	–	transfer(tab, nextTab,
388	–	new Node(SIGN_BIT, nextTab, null, null));
389	–	table = nextTab;
390	–	if (tab == null)
391	–	break;
392	–	}
393	–	} finally {
394	–	resizing = 0;
395	–	}
396	–	}
397	–	else if (table == null)
398	–	Thread.yield(); // lost initialization race; just spin
399	–	return table;
400	–	}
401	–
402	–	/*
403	–	* Reclassifies nodes in each bin to new table.  Because we are
404	–	* using power-of-two expansion, the elements from each bin must
405	–	* either stay at same index, or move with a power of two
406	–	* offset. We eliminate unnecessary node creation by catching
407	–	* cases where old nodes can be reused because their next fields
408	–	* won't change.  Statistically, at the default loadFactor, only
409	–	* about one-sixth of them need cloning when a table doubles. The
410	–	* nodes they replace will be garbage collectable as soon as they
411	–	* are no longer referenced by any reader thread that may be in
412	–	* the midst of concurrently traversing table.
413	–	*
414	–	* Transfers are done from the bottom up to preserve iterator
415	–	* traversability. On each step, the old bin is locked,
416	–	* moved/copied, and then replaced with a forwarding node.
417	–	*/
418	–	private static final void transfer(Node[] tab, Node[] nextTab, Node fwd) {
419	–	int n = tab.length;
420	–	Node ignore = nextTab[n + n - 1]; // force bounds check
421	–	for (int i = n - 1; i >= 0; --i) {
422	–	for (Node e;;) {
423	–	if ((e = tabAt(tab, i)) != null) {
424	–	boolean validated = false;
425	–	synchronized (e) {
426	–	if (tabAt(tab, i) == e) {
427	–	validated = true;
428	–	Node lo = null, hi = null, lastRun = e;
429	–	int runBit = e.hash & n;
430	–	for (Node p = e.next; p != null; p = p.next) {
431	–	int b = p.hash & n;
432	–	if (b != runBit) {
433	–	runBit = b;
434	–	lastRun = p;
435	–	}
436	–	}
437	–	if (runBit == 0)
438	–	lo = lastRun;
439	–	else
440	–	hi = lastRun;
441	–	for (Node p = e; p != lastRun; p = p.next) {
442	–	int ph = p.hash;
443	–	Object pk = p.key, pv = p.val;
444	–	if ((ph & n) == 0)
445	–	lo = new Node(ph, pk, pv, lo);
446	–	else
447	–	hi = new Node(ph, pk, pv, hi);
448	–	}
449	–	setTabAt(nextTab, i, lo);
450	–	setTabAt(nextTab, i + n, hi);
451	–	setTabAt(tab, i, fwd);
452	–	}
453	–	}
454	–	if (validated)
455	–	break;
456	–	}
457	–	else if (casTabAt(tab, i, e, fwd))
458	–	break;
459	–	}
460	–	}
461	–	}
462	–
508		/* ---------------- Internal access and update methods -------------- */
509
510		/**
511		* Applies a supplemental hash function to a given hashCode, which
512		* defends against poor quality hash functions.  The result must
513	<	* be non-negative, and for reasonable performance must have good
514	<	* avalanche properties; i.e., that each bit of the argument
515	<	* affects each bit (except sign bit) of the result.
513	>	* be have the top 2 bits clear. For reasonable performance, this
514	>	* function must have good avalanche properties; i.e., that each
515	>	* bit of the argument affects each bit of the result. (Although
516	>	* we don't care about the unused top 2 bits.)
517		*/
518		private static final int spread(int h) {
519		// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
520	+	// Despite two multiplies, this is often faster than others
521	+	// with comparable bit-spread properties.
522		h ^= h >>> 16;
523		h *= 0x85ebca6b;
524		h ^= h >>> 13;
525		h *= 0xc2b2ae35;
526	<	return (h >>> 16) ^ (h & 0x7fffffff); // mask out sign bit
526	>	return ((h >>> 16) ^ h) & HASH_BITS; // mask out top bits
527		}
528
529		/** Implementation for get and containsKey */
530		private final Object internalGet(Object k) {
531		int h = spread(k.hashCode());
532		retry: for (Node[] tab = table; tab != null;) {
533	<	Node e; Object ek, ev; int eh;  // locals to read fields once
533	>	Node e; Object ek, ev; int eh;    // locals to read fields once
534		for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
535	<	if ((eh = e.hash) == h) {
536	<	if ((ev = e.val) != null &&
489	<	((ek = e.key) == k || k.equals(ek)))
490	<	return ev;
491	<	}
492	<	else if (eh < 0) {          // sign bit set
493	<	tab = (Node[])e.key;    // bin was moved during resize
535	>	if ((eh = e.hash) == MOVED) {
536	>	tab = (Node[])e.key;      // restart with new table
537		continue retry;
538		}
539	+	if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
540	+	((ek = e.key) == k || k.equals(ek)))
541	+	return ev;
542		}
543		break;
544		}
545		return null;
546		}
547
548	<	/** Implementation for put and putIfAbsent */
549	<	private final Object internalPut(Object k, Object v, boolean replace) {
548	>	/**
549	>	* Implementation for the four public remove/replace methods:
550	>	* Replaces node value with v, conditional upon match of cv if
551	>	* non-null.  If resulting value is null, delete.
552	>	*/
553	>	private final Object internalReplace(Object k, Object v, Object cv) {
554		int h = spread(k.hashCode());
555	<	Object oldVal = null;               // previous value or null if none
555	>	Object oldVal = null;
556		for (Node[] tab = table;;) {
557	<	Node e; int i; Object ek, ev;
557	>	Node f; int i, fh;
558	>	if (tab == null ||
559	>	(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
560	>	break;
561	>	else if ((fh = f.hash) == MOVED)
562	>	tab = (Node[])f.key;
563	>	else if ((fh & HASH_BITS) != h && f.next == null) // precheck
564	>	break;                          // rules out possible existence
565	>	else if ((fh & LOCKED) != 0) {
566	>	checkForResize();               // try resizing if can't get lock
567	>	f.tryAwaitLock(tab, i);
568	>	}
569	>	else if (f.casHash(fh, fh | LOCKED)) {
570	>	boolean validated = false;
571	>	boolean deleted = false;
572	>	try {
573	>	if (tabAt(tab, i) == f) {
574	>	validated = true;
575	>	for (Node e = f, pred = null;;) {
576	>	Object ek, ev;
577	>	if ((e.hash & HASH_BITS) == h &&
578	>	((ev = e.val) != null) &&
579	>	((ek = e.key) == k || k.equals(ek))) {
580	>	if (cv == null || cv == ev || cv.equals(ev)) {
581	>	oldVal = ev;
582	>	if ((e.val = v) == null) {
583	>	deleted = true;
584	>	Node en = e.next;
585	>	if (pred != null)
586	>	pred.next = en;
587	>	else
588	>	setTabAt(tab, i, en);
589	>	}
590	>	}
591	>	break;
592	>	}
593	>	pred = e;
594	>	if ((e = e.next) == null)
595	>	break;
596	>	}
597	>	}
598	>	} finally {
599	>	if (!f.casHash(fh | LOCKED, fh)) {
600	>	f.hash = fh;
601	>	synchronized (f) { f.notifyAll(); };
602	>	}
603	>	}
604	>	if (validated) {
605	>	if (deleted)
606	>	counter.add(-1L);
607	>	break;
608	>	}
609	>	}
610	>	}
611	>	return oldVal;
612	>	}
613	>
614	>	/*
615	>	* Internal versions of the five insertion methods, each a
616	>	* little more complicated than the last. All have
617	>	* the same basic structure as the first (internalPut):
618	>	*  1. If table uninitialized, create
619	>	*  2. If bin empty, try to CAS new node
620	>	*  3. If bin stale, use new table
621	>	*  4. Lock and validate; if valid, scan and add or update
622	>	*
623	>	* The others interweave other checks and/or alternative actions:
624	>	*  * Plain put checks for and performs resize after insertion.
625	>	*  * putIfAbsent prescans for mapping without lock (and fails to add
626	>	*    if present), which also makes pre-emptive resize checks worthwhile.
627	>	*  * computeIfAbsent extends form used in putIfAbsent with additional
628	>	*    mechanics to deal with, calls, potential exceptions and null
629	>	*    returns from function call.
630	>	*  * compute uses the same function-call mechanics, but without
631	>	*    the prescans
632	>	*  * putAll attempts to pre-allocate enough table space
633	>	*    and more lazily performs count updates and checks.
634	>	*
635	>	* Someday when details settle down a bit more, it might be worth
636	>	* some factoring to reduce sprawl.
637	>	*/
638	>
639	>	/** Implementation for put */
640	>	private final Object internalPut(Object k, Object v) {
641	>	int h = spread(k.hashCode());
642	>	boolean checkSize = false;
643	>	for (Node[] tab = table;;) {
644	>	int i; Node f; int fh;
645		if (tab == null)
646	<	tab = growTable();
647	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
646	>	tab = initTable();
647	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
648		if (casTabAt(tab, i, null, new Node(h, k, v, null)))
649		break;                   // no lock when adding to empty bin
650		}
651	<	else if (e.hash < 0)             // resized -- restart with new table
652	<	tab = (Node[])e.key;
653	<	else if (!replace && e.hash == h && (ev = e.val) != null &&
654	<	((ek = e.key) == k || k.equals(ek))) {
655	<	if (tabAt(tab, i) == e) {    // inspect and validate 1st node
519	<	oldVal = ev;             // without lock for putIfAbsent
520	<	break;
521	<	}
651	>	else if ((fh = f.hash) == MOVED)
652	>	tab = (Node[])f.key;
653	>	else if ((fh & LOCKED) != 0) {
654	>	checkForResize();
655	>	f.tryAwaitLock(tab, i);
656		}
657	<	else {
657	>	else if (f.casHash(fh, fh | LOCKED)) {
658	>	Object oldVal = null;
659		boolean validated = false;
660	<	boolean checkSize = false;
661	<	synchronized (e) {           // lock the 1st node of bin list
527	<	if (tabAt(tab, i) == e) {
660	>	try {                        // needed in case equals() throws
661	>	if (tabAt(tab, i) == f) {
662		validated = true;    // retry if 1st already deleted
663	<	for (Node first = e;;) {
664	<	if (e.hash == h &&
665	<	((ek = e.key) == k || k.equals(ek)) &&
666	<	(ev = e.val) != null) {
663	>	for (Node e = f;;) {
664	>	Object ek, ev;
665	>	if ((e.hash & HASH_BITS) == h &&
666	>	(ev = e.val) != null &&
667	>	((ek = e.key) == k || k.equals(ek))) {
668		oldVal = ev;
669	<	if (replace)
535	<	e.val = v;
669	>	e.val = v;
670		break;
671		}
672		Node last = e;
673		if ((e = e.next) == null) {
674		last.next = new Node(h, k, v, null);
675	<	if (last != first || tab.length <= 64)
675	>	if (last != f || tab.length <= 64)
676		checkSize = true;
677		break;
678		}
679		}
680		}
681	+	} finally {                  // unlock and signal if needed
682	+	if (!f.casHash(fh | LOCKED, fh)) {
683	+	f.hash = fh;
684	+	synchronized (f) { f.notifyAll(); };
685	+	}
686		}
687		if (validated) {
688	<	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
689	<	resizing == 0 && counter.sum() >= threshold)
551	<	growTable();
688	>	if (oldVal != null)
689	>	return oldVal;
690		break;
691		}
692		}
693		}
694	<	if (oldVal == null)
695	<	counter.increment();             // update counter outside of locks
696	<	return oldVal;
694	>	counter.add(1L);
695	>	if (checkSize)
696	>	checkForResize();
697	>	return null;
698		}
699
700	<	/**
701	<	* Implementation for the four public remove/replace methods:
563	<	* Replaces node value with v, conditional upon match of cv if
564	<	* non-null.  If resulting value is null, delete.
565	<	*/
566	<	private final Object internalReplace(Object k, Object v, Object cv) {
700	>	/** Implementation for putIfAbsent */
701	>	private final Object internalPutIfAbsent(Object k, Object v) {
702		int h = spread(k.hashCode());
703		for (Node[] tab = table;;) {
704	<	Node e; int i;
705	<	if (tab == null ||
706	<	(e = tabAt(tab, i = (tab.length - 1) & h)) == null)
707	<	return null;
708	<	else if (e.hash < 0)
709	<	tab = (Node[])e.key;
704	>	int i; Node f; int fh; Object fk, fv;
705	>	if (tab == null)
706	>	tab = initTable();
707	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
708	>	if (casTabAt(tab, i, null, new Node(h, k, v, null)))
709	>	break;
710	>	}
711	>	else if ((fh = f.hash) == MOVED)
712	>	tab = (Node[])f.key;
713	>	else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
714	>	((fk = f.key) == k || k.equals(fk)))
715	>	return fv;
716		else {
717	<	Object oldVal = null;
718	<	boolean validated = false;
719	<	boolean deleted = false;
720	<	synchronized (e) {
721	<	if (tabAt(tab, i) == e) {
722	<	validated = true;
723	<	Node pred = null;
724	<	do {
725	<	Object ek, ev;
726	<	if (e.hash == h &&
727	<	((ek = e.key) == k || k.equals(ek)) &&
728	<	((ev = e.val) != null)) {
729	<	if (cv == null || cv == ev || cv.equals(ev)) {
717	>	Node g = f.next;
718	>	if (g != null) { // at least 2 nodes -- search and maybe resize
719	>	for (Node e = g;;) {
720	>	Object ek, ev;
721	>	if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
722	>	((ek = e.key) == k || k.equals(ek)))
723	>	return ev;
724	>	if ((e = e.next) == null) {
725	>	checkForResize();
726	>	break;
727	>	}
728	>	}
729	>	}
730	>	if (((fh = f.hash) & LOCKED) != 0) {
731	>	checkForResize();
732	>	f.tryAwaitLock(tab, i);
733	>	}
734	>	else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
735	>	Object oldVal = null;
736	>	boolean validated = false;
737	>	try {
738	>	if (tabAt(tab, i) == f) {
739	>	validated = true;
740	>	for (Node e = f;;) {
741	>	Object ek, ev;
742	>	if ((e.hash & HASH_BITS) == h &&
743	>	(ev = e.val) != null &&
744	>	((ek = e.key) == k || k.equals(ek))) {
745		oldVal = ev;
746	<	if ((e.val = v) == null) {
747	<	deleted = true;
748	<	Node en = e.next;
749	<	if (pred != null)
750	<	pred.next = en;
751	<	else
596	<	setTabAt(tab, i, en);
597	<	}
746	>	break;
747	>	}
748	>	Node last = e;
749	>	if ((e = e.next) == null) {
750	>	last.next = new Node(h, k, v, null);
751	>	break;
752		}
599	–	break;
753		}
754	<	} while ((e = (pred = e).next) != null);
754	>	}
755	>	} finally {
756	>	if (!f.casHash(fh | LOCKED, fh)) {
757	>	f.hash = fh;
758	>	synchronized (f) { f.notifyAll(); };
759	>	}
760	>	}
761	>	if (validated) {
762	>	if (oldVal != null)
763	>	return oldVal;
764	>	break;
765		}
766		}
767	<	if (validated) {
768	<	if (deleted)
769	<	counter.decrement();
770	<	return oldVal;
767	>	}
768	>	}
769	>	counter.add(1L);
770	>	return null;
771	>	}
772	>
773	>	/** Implementation for computeIfAbsent */
774	>	private final Object internalComputeIfAbsent(K k,
775	>	MappingFunction<? super K, ?> mf) {
776	>	int h = spread(k.hashCode());
777	>	Object val = null;
778	>	for (Node[] tab = table;;) {
779	>	Node f; int i, fh; Object fk, fv;
780	>	if (tab == null)
781	>	tab = initTable();
782	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
783	>	Node node = new Node(fh = h | LOCKED, k, null, null);
784	>	boolean validated = false;
785	>	if (casTabAt(tab, i, null, node)) {
786	>	validated = true;
787	>	try {
788	>	if ((val = mf.map(k)) != null)
789	>	node.val = val;
790	>	} finally {
791	>	if (val == null)
792	>	setTabAt(tab, i, null);
793	>	if (!node.casHash(fh, h)) {
794	>	node.hash = h;
795	>	synchronized (node) { node.notifyAll(); };
796	>	}
797	>	}
798	>	}
799	>	if (validated)
800	>	break;
801	>	}
802	>	else if ((fh = f.hash) == MOVED)
803	>	tab = (Node[])f.key;
804	>	else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
805	>	((fk = f.key) == k || k.equals(fk)))
806	>	return fv;
807	>	else {
808	>	Node g = f.next;
809	>	if (g != null) {
810	>	for (Node e = g;;) {
811	>	Object ek, ev;
812	>	if ((e.hash & HASH_BITS) == h && (ev = e.val) != null &&
813	>	((ek = e.key) == k || k.equals(ek)))
814	>	return ev;
815	>	if ((e = e.next) == null) {
816	>	checkForResize();
817	>	break;
818	>	}
819	>	}
820	>	}
821	>	if (((fh = f.hash) & LOCKED) != 0) {
822	>	checkForResize();
823	>	f.tryAwaitLock(tab, i);
824	>	}
825	>	else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
826	>	boolean validated = false;
827	>	try {
828	>	if (tabAt(tab, i) == f) {
829	>	validated = true;
830	>	for (Node e = f;;) {
831	>	Object ek, ev;
832	>	if ((e.hash & HASH_BITS) == h &&
833	>	(ev = e.val) != null &&
834	>	((ek = e.key) == k || k.equals(ek))) {
835	>	val = ev;
836	>	break;
837	>	}
838	>	Node last = e;
839	>	if ((e = e.next) == null) {
840	>	if ((val = mf.map(k)) != null)
841	>	last.next = new Node(h, k, val, null);
842	>	break;
843	>	}
844	>	}
845	>	}
846	>	} finally {
847	>	if (!f.casHash(fh | LOCKED, fh)) {
848	>	f.hash = fh;
849	>	synchronized (f) { f.notifyAll(); };
850	>	}
851	>	}
852	>	if (validated)
853	>	break;
854		}
855		}
856		}
857	+	if (val == null)
858	+	throw new NullPointerException();
859	+	counter.add(1L);
860	+	return val;
861		}
862
863	<	/** Implementation for computeIfAbsent and compute. Like put, but messier. */
863	>	/** Implementation for compute */
864		@SuppressWarnings("unchecked")
865	<	private final V internalCompute(K k,
866	<	MappingFunction<? super K, ? extends V> f,
617	<	boolean replace) {
865	>	private final Object internalCompute(K k,
866	>	RemappingFunction<? super K, V> mf) {
867		int h = spread(k.hashCode());
868	<	V val = null;
868	>	Object val = null;
869		boolean added = false;
870	<	Node[] tab = table;
871	<	outer:for (;;) {
872	<	Node e; int i; Object ek, ev;
870	>	boolean checkSize = false;
871	>	for (Node[] tab = table;;) {
872	>	Node f; int i, fh;
873		if (tab == null)
874	<	tab = growTable();
875	<	else if ((e = tabAt(tab, i = (tab.length - 1) & h)) == null) {
876	<	Node node = new Node(h, k, null, null);
874	>	tab = initTable();
875	>	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
876	>	Node node = new Node(fh = h | LOCKED, k, null, null);
877		boolean validated = false;
878	<	synchronized (node) {  // must lock while computing value
879	<	if (casTabAt(tab, i, null, node)) {
880	<	validated = true;
881	<	try {
882	<	val = f.map(k);
883	<	if (val != null) {
884	<	node.val = val;
885	<	added = true;
886	<	}
887	<	} finally {
888	<	if (!added)
889	<	setTabAt(tab, i, null);
878	>	if (casTabAt(tab, i, null, node)) {
879	>	validated = true;
880	>	try {
881	>	if ((val = mf.remap(k, null)) != null) {
882	>	node.val = val;
883	>	added = true;
884	>	}
885	>	} finally {
886	>	if (!added)
887	>	setTabAt(tab, i, null);
888	>	if (!node.casHash(fh, h)) {
889	>	node.hash = h;
890	>	synchronized (node) { node.notifyAll(); };
891		}
892		}
893		}
894		if (validated)
895		break;
896		}
897	<	else if (e.hash < 0)
898	<	tab = (Node[])e.key;
899	<	else if (!replace && e.hash == h && (ev = e.val) != null &&
900	<	((ek = e.key) == k || k.equals(ek))) {
901	<	if (tabAt(tab, i) == e) {
652	<	val = (V)ev;
653	<	break;
654	<	}
897	>	else if ((fh = f.hash) == MOVED)
898	>	tab = (Node[])f.key;
899	>	else if ((fh & LOCKED) != 0) {
900	>	checkForResize();
901	>	f.tryAwaitLock(tab, i);
902		}
903	<	else if (Thread.holdsLock(e))
657	<	throw new IllegalStateException("Recursive map computation");
658	<	else {
903	>	else if (f.casHash(fh, fh | LOCKED)) {
904		boolean validated = false;
905	<	boolean checkSize = false;
906	<	synchronized (e) {
662	<	if (tabAt(tab, i) == e) {
905	>	try {
906	>	if (tabAt(tab, i) == f) {
907		validated = true;
908	<	for (Node first = e;;) {
909	<	if (e.hash == h &&
910	<	((ek = e.key) == k || k.equals(ek)) &&
911	<	((ev = e.val) != null)) {
912	<	Object fv;
913	<	if (replace && (fv = f.map(k)) != null)
914	<	ev = e.val = fv;
915	<	val = (V)ev;
908	>	for (Node e = f;;) {
909	>	Object ek, ev;
910	>	if ((e.hash & HASH_BITS) == h &&
911	>	(ev = e.val) != null &&
912	>	((ek = e.key) == k || k.equals(ek))) {
913	>	val = mf.remap(k, (V)ev);
914	>	if (val != null)
915	>	e.val = val;
916		break;
917		}
918		Node last = e;
919		if ((e = e.next) == null) {
920	<	if ((val = f.map(k)) != null) {
920	>	if ((val = mf.remap(k, null)) != null) {
921		last.next = new Node(h, k, val, null);
922		added = true;
923	<	if (last != first || tab.length <= 64)
923	>	if (last != f || tab.length <= 64)
924		checkSize = true;
925		}
926		break;
927		}
928		}
929		}
930	+	} finally {
931	+	if (!f.casHash(fh | LOCKED, fh)) {
932	+	f.hash = fh;
933	+	synchronized (f) { f.notifyAll(); };
934	+	}
935		}
936	<	if (validated) {
688	<	if (checkSize && tab.length < MAXIMUM_CAPACITY &&
689	<	resizing == 0 && counter.sum() >= threshold)
690	<	growTable();
936	>	if (validated)
937		break;
692	–	}
938		}
939		}
940	<	if (added)
941	<	counter.increment();
940	>	if (val == null)
941	>	throw new NullPointerException();
942	>	if (added) {
943	>	counter.add(1L);
944	>	if (checkSize)
945	>	checkForResize();
946	>	}
947		return val;
948		}
949
950	+	/** Implementation for putAll */
951	+	private final void internalPutAll(Map<?, ?> m) {
952	+	tryPresize(m.size());
953	+	long delta = 0L;     // number of uncommitted additions
954	+	boolean npe = false; // to throw exception on exit for nulls
955	+	try {                // to clean up counts on other exceptions
956	+	for (Map.Entry<?, ?> entry : m.entrySet()) {
957	+	Object k, v;
958	+	if (entry == null || (k = entry.getKey()) == null ||
959	+	(v = entry.getValue()) == null) {
960	+	npe = true;
961	+	break;
962	+	}
963	+	int h = spread(k.hashCode());
964	+	for (Node[] tab = table;;) {
965	+	int i; Node f; int fh;
966	+	if (tab == null)
967	+	tab = initTable();
968	+	else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
969	+	if (casTabAt(tab, i, null, new Node(h, k, v, null))) {
970	+	++delta;
971	+	break;
972	+	}
973	+	}
974	+	else if ((fh = f.hash) == MOVED)
975	+	tab = (Node[])f.key;
976	+	else if ((fh & LOCKED) != 0) {
977	+	counter.add(delta);
978	+	delta = 0L;
979	+	checkForResize();
980	+	f.tryAwaitLock(tab, i);
981	+	}
982	+	else if (f.casHash(fh, fh | LOCKED)) {
983	+	boolean validated = false;
984	+	boolean tooLong = false;
985	+	try {
986	+	if (tabAt(tab, i) == f) {
987	+	validated = true;
988	+	for (Node e = f;;) {
989	+	Object ek, ev;
990	+	if ((e.hash & HASH_BITS) == h &&
991	+	(ev = e.val) != null &&
992	+	((ek = e.key) == k || k.equals(ek))) {
993	+	e.val = v;
994	+	break;
995	+	}
996	+	Node last = e;
997	+	if ((e = e.next) == null) {
998	+	++delta;
999	+	last.next = new Node(h, k, v, null);
1000	+	break;
1001	+	}
1002	+	tooLong = true;
1003	+	}
1004	+	}
1005	+	} finally {
1006	+	if (!f.casHash(fh | LOCKED, fh)) {
1007	+	f.hash = fh;
1008	+	synchronized (f) { f.notifyAll(); };
1009	+	}
1010	+	}
1011	+	if (validated) {
1012	+	if (tooLong) {
1013	+	counter.add(delta);
1014	+	delta = 0L;
1015	+	checkForResize();
1016	+	}
1017	+	break;
1018	+	}
1019	+	}
1020	+	}
1021	+	}
1022	+	} finally {
1023	+	if (delta != 0)
1024	+	counter.add(delta);
1025	+	}
1026	+	if (npe)
1027	+	throw new NullPointerException();
1028	+	}
1029	+
1030	+	/* ---------------- Table Initialization and Resizing -------------- */
1031	+
1032	+	/**
1033	+	* Returns a power of two table size for the given desired capacity.
1034	+	* See Hackers Delight, sec 3.2
1035	+	*/
1036	+	private static final int tableSizeFor(int c) {
1037	+	int n = c - 1;
1038	+	n |= n >>> 1;
1039	+	n |= n >>> 2;
1040	+	n |= n >>> 4;
1041	+	n |= n >>> 8;
1042	+	n |= n >>> 16;
1043	+	return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
1044	+	}
1045	+
1046	+	/**
1047	+	* Initializes table, using the size recorded in sizeCtl.
1048	+	*/
1049	+	private final Node[] initTable() {
1050	+	Node[] tab; int sc;
1051	+	while ((tab = table) == null) {
1052	+	if ((sc = sizeCtl) < 0)
1053	+	Thread.yield(); // lost initialization race; just spin
1054	+	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1055	+	try {
1056	+	if ((tab = table) == null) {
1057	+	int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
1058	+	tab = table = new Node[n];
1059	+	sc = n - (n >>> 2);
1060	+	}
1061	+	} finally {
1062	+	sizeCtl = sc;
1063	+	}
1064	+	break;
1065	+	}
1066	+	}
1067	+	return tab;
1068	+	}
1069	+
1070	+	/**
1071	+	* If table is too small and not already resizing, creates next
1072	+	* table and transfers bins.  Rechecks occupancy after a transfer
1073	+	* to see if another resize is already needed because resizings
1074	+	* are lagging additions.
1075	+	*/
1076	+	private final void checkForResize() {
1077	+	Node[] tab; int n, sc;
1078	+	while ((tab = table) != null &&
1079	+	(n = tab.length) < MAXIMUM_CAPACITY &&
1080	+	(sc = sizeCtl) >= 0 && counter.sum() >= (long)sc &&
1081	+	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1082	+	try {
1083	+	if (tab == table) {
1084	+	table = rebuild(tab);
1085	+	sc = (n << 1) - (n >>> 1);
1086	+	}
1087	+	} finally {
1088	+	sizeCtl = sc;
1089	+	}
1090	+	}
1091	+	}
1092	+
1093		/**
1094	<	* Implementation for clear. Steps through each bin, removing all nodes.
1094	>	* Tries to presize table to accommodate the given number of elements.
1095	>	*
1096	>	* @param size number of elements (doesn't need to be perfectly accurate)
1097	>	*/
1098	>	private final void tryPresize(int size) {
1099	>	int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1100	>	tableSizeFor(size + (size >>> 1) + 1);
1101	>	int sc;
1102	>	while ((sc = sizeCtl) >= 0) {
1103	>	Node[] tab = table; int n;
1104	>	if (tab == null || (n = tab.length) == 0) {
1105	>	n = (sc > c) ? sc : c;
1106	>	if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1107	>	try {
1108	>	if (table == tab) {
1109	>	table = new Node[n];
1110	>	sc = n - (n >>> 2);
1111	>	}
1112	>	} finally {
1113	>	sizeCtl = sc;
1114	>	}
1115	>	}
1116	>	}
1117	>	else if (c <= sc || n >= MAXIMUM_CAPACITY)
1118	>	break;
1119	>	else if (UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
1120	>	try {
1121	>	if (table == tab) {
1122	>	table = rebuild(tab);
1123	>	sc = (n << 1) - (n >>> 1);
1124	>	}
1125	>	} finally {
1126	>	sizeCtl = sc;
1127	>	}
1128	>	}
1129	>	}
1130	>	}
1131	>
1132	>	/*
1133	>	* Moves and/or copies the nodes in each bin to new table. See
1134	>	* above for explanation.
1135	>	*
1136	>	* @return the new table
1137	>	*/
1138	>	private static final Node[] rebuild(Node[] tab) {
1139	>	int n = tab.length;
1140	>	Node[] nextTab = new Node[n << 1];
1141	>	Node fwd = new Node(MOVED, nextTab, null, null);
1142	>	int[] buffer = null;       // holds bins to revisit; null until needed
1143	>	Node rev = null;           // reverse forwarder; null until needed
1144	>	int nbuffered = 0;         // the number of bins in buffer list
1145	>	int bufferIndex = 0;       // buffer index of current buffered bin
1146	>	int bin = n - 1;           // current non-buffered bin or -1 if none
1147	>
1148	>	for (int i = bin;;) {      // start upwards sweep
1149	>	int fh; Node f;
1150	>	if ((f = tabAt(tab, i)) == null) {
1151	>	if (bin >= 0) {    // no lock needed (or available)
1152	>	if (!casTabAt(tab, i, f, fwd))
1153	>	continue;
1154	>	}
1155	>	else {             // transiently use a locked forwarding node
1156	>	Node g = new Node(MOVED|LOCKED, nextTab, null, null);
1157	>	if (!casTabAt(tab, i, f, g))
1158	>	continue;
1159	>	setTabAt(nextTab, i, null);
1160	>	setTabAt(nextTab, i + n, null);
1161	>	setTabAt(tab, i, fwd);
1162	>	if (!g.casHash(MOVED|LOCKED, MOVED)) {
1163	>	g.hash = MOVED;
1164	>	synchronized (g) { g.notifyAll(); }
1165	>	}
1166	>	}
1167	>	}
1168	>	else if (((fh = f.hash) & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
1169	>	boolean validated = false;
1170	>	try {              // split to lo and hi lists; copying as needed
1171	>	if (tabAt(tab, i) == f) {
1172	>	validated = true;
1173	>	Node e = f, lastRun = f;
1174	>	Node lo = null, hi = null;
1175	>	int runBit = e.hash & n;
1176	>	for (Node p = e.next; p != null; p = p.next) {
1177	>	int b = p.hash & n;
1178	>	if (b != runBit) {
1179	>	runBit = b;
1180	>	lastRun = p;
1181	>	}
1182	>	}
1183	>	if (runBit == 0)
1184	>	lo = lastRun;
1185	>	else
1186	>	hi = lastRun;
1187	>	for (Node p = e; p != lastRun; p = p.next) {
1188	>	int ph = p.hash & HASH_BITS;
1189	>	Object pk = p.key, pv = p.val;
1190	>	if ((ph & n) == 0)
1191	>	lo = new Node(ph, pk, pv, lo);
1192	>	else
1193	>	hi = new Node(ph, pk, pv, hi);
1194	>	}
1195	>	setTabAt(nextTab, i, lo);
1196	>	setTabAt(nextTab, i + n, hi);
1197	>	setTabAt(tab, i, fwd);
1198	>	}
1199	>	} finally {
1200	>	if (!f.casHash(fh | LOCKED, fh)) {
1201	>	f.hash = fh;
1202	>	synchronized (f) { f.notifyAll(); };
1203	>	}
1204	>	}
1205	>	if (!validated)
1206	>	continue;
1207	>	}
1208	>	else {
1209	>	if (buffer == null) // initialize buffer for revisits
1210	>	buffer = new int[TRANSFER_BUFFER_SIZE];
1211	>	if (bin < 0 && bufferIndex > 0) {
1212	>	int j = buffer[--bufferIndex];
1213	>	buffer[bufferIndex] = i;
1214	>	i = j;         // swap with another bin
1215	>	continue;
1216	>	}
1217	>	if (bin < 0 || nbuffered >= TRANSFER_BUFFER_SIZE) {
1218	>	f.tryAwaitLock(tab, i);
1219	>	continue;      // no other options -- block
1220	>	}
1221	>	if (rev == null)   // initialize reverse-forwarder
1222	>	rev = new Node(MOVED, tab, null, null);
1223	>	if (tabAt(tab, i) != f || (f.hash & LOCKED) == 0)
1224	>	continue;      // recheck before adding to list
1225	>	buffer[nbuffered++] = i;
1226	>	setTabAt(nextTab, i, rev);     // install place-holders
1227	>	setTabAt(nextTab, i + n, rev);
1228	>	}
1229	>
1230	>	if (bin > 0)
1231	>	i = --bin;
1232	>	else if (buffer != null && nbuffered > 0) {
1233	>	bin = -1;
1234	>	i = buffer[bufferIndex = --nbuffered];
1235	>	}
1236	>	else
1237	>	return nextTab;
1238	>	}
1239	>	}
1240	>
1241	>	/**
1242	>	* Implementation for clear. Steps through each bin, removing all
1243	>	* nodes.
1244		*/
1245		private final void internalClear() {
1246		long delta = 0L; // negative number of deletions
1247		int i = 0;
1248		Node[] tab = table;
1249		while (tab != null && i < tab.length) {
1250	<	Node e = tabAt(tab, i);
1251	<	if (e == null)
1250	>	int fh;
1251	>	Node f = tabAt(tab, i);
1252	>	if (f == null)
1253		++i;
1254	<	else if (e.hash < 0)
1255	<	tab = (Node[])e.key;
1256	<	else {
1254	>	else if ((fh = f.hash) == MOVED)
1255	>	tab = (Node[])f.key;
1256	>	else if ((fh & LOCKED) != 0) {
1257	>	counter.add(delta); // opportunistically update count
1258	>	delta = 0L;
1259	>	f.tryAwaitLock(tab, i);
1260	>	}
1261	>	else if (f.casHash(fh, fh | LOCKED)) {
1262		boolean validated = false;
1263	<	synchronized (e) {
1264	<	if (tabAt(tab, i) == e) {
1263	>	try {
1264	>	if (tabAt(tab, i) == f) {
1265		validated = true;
1266	<	Node en;
719	<	do {
720	<	en = e.next;
1266	>	for (Node e = f; e != null; e = e.next) {
1267		if (e.val != null) { // currently always true
1268		e.val = null;
1269		--delta;
1270		}
1271	<	} while ((e = en) != null);
1271	>	}
1272		setTabAt(tab, i, null);
1273		}
1274	+	} finally {
1275	+	if (!f.casHash(fh | LOCKED, fh)) {
1276	+	f.hash = fh;
1277	+	synchronized (f) { f.notifyAll(); };
1278	+	}
1279		}
1280		if (validated)
1281		++i;
1282		}
1283		}
1284	<	counter.add(delta);
1284	>	if (delta != 0)
1285	>	counter.add(delta);
1286		}
1287
1288	+
1289		/* ----------------Table Traversal -------------- */
1290
1291		/**
#	Line 741 | Line 1294 | public class ConcurrentHashMapV8<K, V>
1294		*
1295		* At each step, the iterator snapshots the key ("nextKey") and
1296		* value ("nextVal") of a valid node (i.e., one that, at point of
1297	<	* snapshot, has a nonnull user value). Because val fields can
1297	>	* snapshot, has a non-null user value). Because val fields can
1298		* change (including to null, indicating deletion), field nextVal
1299		* might not be accurate at point of use, but still maintains the
1300		* weak consistency property of holding a value that was once
1301		* valid.
1302		*
1303		* Internal traversals directly access these fields, as in:
1304	<	* {@code while (it.next != null) { process(nextKey); it.advance(); }}
1304	>	* {@code while (it.next != null) { process(it.nextKey); it.advance(); }}
1305		*
1306		* Exported iterators (subclasses of ViewIterator) extract key,
1307		* value, or key-value pairs as return values of Iterator.next(),
1308	<	* and encapulate the it.next check as hasNext();
1308	>	* and encapsulate the it.next check as hasNext();
1309		*
1310	<	* The iterator visits each valid node that was reachable upon
1311	<	* iterator construction once. It might miss some that were added
1312	<	* to a bin after the bin was visited, which is OK wrt consistency
1313	<	* guarantees. Maintaining this property in the face of possible
1314	<	* ongoing resizes requires a fair amount of bookkeeping state
1315	<	* that is difficult to optimize away amidst volatile accesses.
1316	<	* Even so, traversal maintains reasonable throughput.
1310	>	* The iterator visits once each still-valid node that was
1311	>	* reachable upon iterator construction. It might miss some that
1312	>	* were added to a bin after the bin was visited, which is OK wrt
1313	>	* consistency guarantees. Maintaining this property in the face
1314	>	* of possible ongoing resizes requires a fair amount of
1315	>	* bookkeeping state that is difficult to optimize away amidst
1316	>	* volatile accesses.  Even so, traversal maintains reasonable
1317	>	* throughput.
1318		*
1319		* Normally, iteration proceeds bin-by-bin traversing lists.
1320		* However, if the table has been resized, then all future steps
#	Line 797 | Line 1351 | public class ConcurrentHashMapV8<K, V>
1351		InternalIterator(Node[] tab, int lo, int hi) {
1352		this.tab = tab;
1353		baseSize = (tab == null) ? 0 : tab.length;
1354	<	baseLimit = (hi <= baseSize)? hi : baseSize;
1355	<	index = baseIndex = lo;
1354	>	baseLimit = (hi <= baseSize) ? hi : baseSize;
1355	>	index = baseIndex = (lo >= 0) ? lo : 0;
1356		next = null;
1357		advance();
1358		}
#	Line 807 | Line 1361 | public class ConcurrentHashMapV8<K, V>
1361		final void advance() {
1362		Node e = last = next;
1363		outer: do {
1364	<	if (e != null)                   // pass used or skipped node
1364	>	if (e != null)                  // advance past used/skipped node
1365		e = e.next;
1366	<	while (e == null) {              // get to next non-null bin
1367	<	Node[] t; int b, i, n;       // checks must use locals
1366	>	while (e == null) {             // get to next non-null bin
1367	>	Node[] t; int b, i, n;      // checks must use locals
1368		if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
1369		(t = tab) == null || i >= (n = t.length))
1370		break outer;
1371	<	else if ((e = tabAt(t, i)) != null && e.hash < 0)
1372	<	tab = (Node[])e.key;     // restarts due to null val
1373	<	else                         // visit upper slots if present
1371	>	else if ((e = tabAt(t, i)) != null && e.hash == MOVED)
1372	>	tab = (Node[])e.key;    // restarts due to null val
1373	>	else                        // visit upper slots if present
1374		index = (i += baseSize) < n ? i : (baseIndex = b + 1);
1375		}
1376		nextKey = e.key;
1377	<	} while ((nextVal = e.val) == null); // skip deleted or special nodes
1377	>	} while ((nextVal = e.val) == null);// skip deleted or special nodes
1378		next = e;
1379		}
1380		}
#	Line 828 | Line 1382 | public class ConcurrentHashMapV8<K, V>
1382		/* ---------------- Public operations -------------- */
1383
1384		/**
1385	<	* Creates a new, empty map with the specified initial
832	<	* capacity, load factor and concurrency level.
833	<	*
834	<	* @param initialCapacity the initial capacity. The implementation
835	<	* performs internal sizing to accommodate this many elements.
836	<	* @param loadFactor  the load factor threshold, used to control resizing.
837	<	* Resizing may be performed when the average number of elements per
838	<	* bin exceeds this threshold.
839	<	* @param concurrencyLevel the estimated number of concurrently
840	<	* updating threads. The implementation may use this value as
841	<	* a sizing hint.
842	<	* @throws IllegalArgumentException if the initial capacity is
843	<	* negative or the load factor or concurrencyLevel are
844	<	* nonpositive.
1385	>	* Creates a new, empty map with the default initial table size (16),
1386		*/
1387	<	public ConcurrentHashMapV8(int initialCapacity,
847	<	float loadFactor, int concurrencyLevel) {
848	<	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
849	<	throw new IllegalArgumentException();
850	<	int cap = tableSizeFor(initialCapacity);
1387	>	public ConcurrentHashMapV8() {
1388		this.counter = new LongAdder();
852	–	this.loadFactor = loadFactor;
853	–	this.targetCapacity = cap;
1389		}
1390
1391		/**
1392	<	* Creates a new, empty map with the specified initial capacity
1393	<	* and load factor and with the default concurrencyLevel (16).
1392	>	* Creates a new, empty map with an initial table size
1393	>	* accommodating the specified number of elements without the need
1394	>	* to dynamically resize.
1395		*
1396		* @param initialCapacity The implementation performs internal
1397		* sizing to accommodate this many elements.
862	–	* @param loadFactor  the load factor threshold, used to control resizing.
863	–	* Resizing may be performed when the average number of elements per
864	–	* bin exceeds this threshold.
1398		* @throws IllegalArgumentException if the initial capacity of
1399	<	* elements is negative or the load factor is nonpositive
867	<	*
868	<	* @since 1.6
1399	>	* elements is negative
1400		*/
1401	<	public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
1402	<	this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL);
1401	>	public ConcurrentHashMapV8(int initialCapacity) {
1402	>	if (initialCapacity < 0)
1403	>	throw new IllegalArgumentException();
1404	>	int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ?
1405	>	MAXIMUM_CAPACITY :
1406	>	tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
1407	>	this.counter = new LongAdder();
1408	>	this.sizeCtl = cap;
1409		}
1410
1411		/**
1412	<	* Creates a new, empty map with the specified initial capacity,
876	<	* and with default load factor (0.75) and concurrencyLevel (16).
1412	>	* Creates a new map with the same mappings as the given map.
1413		*
1414	<	* @param initialCapacity the initial capacity. The implementation
879	<	* performs internal sizing to accommodate this many elements.
880	<	* @throws IllegalArgumentException if the initial capacity of
881	<	* elements is negative.
1414	>	* @param m the map
1415		*/
1416	<	public ConcurrentHashMapV8(int initialCapacity) {
1417	<	this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1416	>	public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
1417	>	this.counter = new LongAdder();
1418	>	this.sizeCtl = DEFAULT_CAPACITY;
1419	>	internalPutAll(m);
1420		}
1421
1422		/**
1423	<	* Creates a new, empty map with a default initial capacity (16),
1424	<	* load factor (0.75) and concurrencyLevel (16).
1423	>	* Creates a new, empty map with an initial table size based on
1424	>	* the given number of elements ({@code initialCapacity}) and
1425	>	* initial table density ({@code loadFactor}).
1426	>	*
1427	>	* @param initialCapacity the initial capacity. The implementation
1428	>	* performs internal sizing to accommodate this many elements,
1429	>	* given the specified load factor.
1430	>	* @param loadFactor the load factor (table density) for
1431	>	* establishing the initial table size
1432	>	* @throws IllegalArgumentException if the initial capacity of
1433	>	* elements is negative or the load factor is nonpositive
1434	>	*
1435	>	* @since 1.6
1436		*/
1437	<	public ConcurrentHashMapV8() {
1438	<	this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1437	>	public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
1438	>	this(initialCapacity, loadFactor, 1);
1439		}
1440
1441		/**
1442	<	* Creates a new map with the same mappings as the given map.
1443	<	* The map is created with a capacity of 1.5 times the number
1444	<	* of mappings in the given map or 16 (whichever is greater),
1445	<	* and a default load factor (0.75) and concurrencyLevel (16).
1442	>	* Creates a new, empty map with an initial table size based on
1443	>	* the given number of elements ({@code initialCapacity}), table
1444	>	* density ({@code loadFactor}), and number of concurrently
1445	>	* updating threads ({@code concurrencyLevel}).
1446		*
1447	<	* @param m the map
1447	>	* @param initialCapacity the initial capacity. The implementation
1448	>	* performs internal sizing to accommodate this many elements,
1449	>	* given the specified load factor.
1450	>	* @param loadFactor the load factor (table density) for
1451	>	* establishing the initial table size
1452	>	* @param concurrencyLevel the estimated number of concurrently
1453	>	* updating threads. The implementation may use this value as
1454	>	* a sizing hint.
1455	>	* @throws IllegalArgumentException if the initial capacity is
1456	>	* negative or the load factor or concurrencyLevel are
1457	>	* nonpositive
1458		*/
1459	<	public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
1460	<	this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL);
1461	<	putAll(m);
1459	>	public ConcurrentHashMapV8(int initialCapacity,
1460	>	float loadFactor, int concurrencyLevel) {
1461	>	if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
1462	>	throw new IllegalArgumentException();
1463	>	if (initialCapacity < concurrencyLevel)   // Use at least as many bins
1464	>	initialCapacity = concurrencyLevel;   // as estimated threads
1465	>	long size = (long)(1.0 + (long)initialCapacity / loadFactor);
1466	>	int cap = ((size >= (long)MAXIMUM_CAPACITY) ?
1467	>	MAXIMUM_CAPACITY: tableSizeFor((int)size));
1468	>	this.counter = new LongAdder();
1469	>	this.sizeCtl = cap;
1470		}
1471
1472		/**
#	Line 917 | Line 1481 | public class ConcurrentHashMapV8<K, V>
1481		*/
1482		public int size() {
1483		long n = counter.sum();
1484	<	return ((n < 0L)? 0 :
1485	<	(n > (long)Integer.MAX_VALUE)? Integer.MAX_VALUE :
1484	>	return ((n < 0L) ? 0 :
1485	>	(n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE :
1486		(int)n);
1487		}
1488
1489	+	final long longSize() { // accurate version of size needed for views
1490	+	long n = counter.sum();
1491	+	return (n < 0L) ? 0L : n;
1492	+	}
1493	+
1494		/**
1495		* Returns the value to which the specified key is mapped,
1496		* or {@code null} if this map contains no mapping for the key.
#	Line 946 | Line 1515 | public class ConcurrentHashMapV8<K, V>
1515		* @param  key   possible key
1516		* @return {@code true} if and only if the specified object
1517		*         is a key in this table, as determined by the
1518	<	*         {@code equals} method; {@code false} otherwise.
1518	>	*         {@code equals} method; {@code false} otherwise
1519		* @throws NullPointerException if the specified key is null
1520		*/
1521		public boolean containsKey(Object key) {
#	Line 1014 | Line 1583 | public class ConcurrentHashMapV8<K, V>
1583		public V put(K key, V value) {
1584		if (key == null || value == null)
1585		throw new NullPointerException();
1586	<	return (V)internalPut(key, value, true);
1586	>	return (V)internalPut(key, value);
1587		}
1588
1589		/**
#	Line 1028 | Line 1597 | public class ConcurrentHashMapV8<K, V>
1597		public V putIfAbsent(K key, V value) {
1598		if (key == null || value == null)
1599		throw new NullPointerException();
1600	<	return (V)internalPut(key, value, false);
1600	>	return (V)internalPutIfAbsent(key, value);
1601		}
1602
1603		/**
#	Line 1039 | Line 1608 | public class ConcurrentHashMapV8<K, V>
1608		* @param m mappings to be stored in this map
1609		*/
1610		public void putAll(Map<? extends K, ? extends V> m) {
1611	<	if (m == null)
1043	<	throw new NullPointerException();
1044	<	/*
1045	<	* If uninitialized, try to adjust targetCapacity to
1046	<	* accommodate the given number of elements.
1047	<	*/
1048	<	if (table == null) {
1049	<	int size = m.size();
1050	<	int cap = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY :
1051	<	tableSizeFor(size + (size >>> 1));
1052	<	if (cap > targetCapacity)
1053	<	targetCapacity = cap;
1054	<	}
1055	<	for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
1056	<	put(e.getKey(), e.getValue());
1611	>	internalPutAll(m);
1612		}
1613
1614		/**
1615		* If the specified key is not already associated with a value,
1616	<	* computes its value using the given mappingFunction, and if
1617	<	* non-null, enters it into the map.  This is equivalent to
1618	<	*  <pre> {@code
1616	>	* computes its value using the given mappingFunction and
1617	>	* enters it into the map.  This is equivalent to
1618	>	* <pre> {@code
1619		* if (map.containsKey(key))
1620		*   return map.get(key);
1621		* value = mappingFunction.map(key);
1622	<	* if (value != null)
1068	<	*   map.put(key, value);
1622	>	* map.put(key, value);
1623		* return value;}</pre>
1624		*
1625	<	* except that the action is performed atomically.  Some attempted
1626	<	* update operations on this map by other threads may be blocked
1627	<	* while computation is in progress, so the computation should be
1628	<	* short and simple, and must not attempt to update any other
1629	<	* mappings of this Map. The most appropriate usage is to
1630	<	* construct a new object serving as an initial mapped value, or
1631	<	* memoized result, as in:
1625	>	* except that the action is performed atomically.  If the
1626	>	* function returns {@code null} (in which case a {@code
1627	>	* NullPointerException} is thrown), or the function itself throws
1628	>	* an (unchecked) exception, the exception is rethrown to its
1629	>	* caller, and no mapping is recorded.  Some attempted update
1630	>	* operations on this map by other threads may be blocked while
1631	>	* computation is in progress, so the computation should be short
1632	>	* and simple, and must not attempt to update any other mappings
1633	>	* of this Map. The most appropriate usage is to construct a new
1634	>	* object serving as an initial mapped value, or memoized result,
1635	>	* as in:
1636	>	*
1637		*  <pre> {@code
1638		* map.computeIfAbsent(key, new MappingFunction<K, V>() {
1639		*   public V map(K k) { return new Value(f(k)); }});}</pre>
#	Line 1082 | Line 1641 | public class ConcurrentHashMapV8<K, V>
1641		* @param key key with which the specified value is to be associated
1642		* @param mappingFunction the function to compute a value
1643		* @return the current (existing or computed) value associated with
1644	<	*         the specified key, or {@code null} if the computation
1645	<	*         returned {@code null}.
1646	<	* @throws NullPointerException if the specified key or mappingFunction
1088	<	*         is null,
1644	>	*         the specified key.
1645	>	* @throws NullPointerException if the specified key, mappingFunction,
1646	>	*         or computed value is null
1647		* @throws IllegalStateException if the computation detectably
1648		*         attempts a recursive update to this map that would
1649	<	*         otherwise never complete.
1649	>	*         otherwise never complete
1650		* @throws RuntimeException or Error if the mappingFunction does so,
1651	<	*         in which case the mapping is left unestablished.
1651	>	*         in which case the mapping is left unestablished
1652		*/
1653	+	@SuppressWarnings("unchecked")
1654		public V computeIfAbsent(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
1655		if (key == null || mappingFunction == null)
1656		throw new NullPointerException();
1657	<	return internalCompute(key, mappingFunction, false);
1657	>	return (V)internalComputeIfAbsent(key, mappingFunction);
1658		}
1659
1660		/**
1661	<	* Computes the value associated with the given key using the given
1662	<	* mappingFunction, and if non-null, enters it into the map.  This
1663	<	* is equivalent to
1661	>	* Computes and enters a new mapping value given a key and
1662	>	* its current mapped value (or {@code null} if there is no current
1663	>	* mapping). This is equivalent to
1664		*  <pre> {@code
1665	<	* value = mappingFunction.map(key);
1666	<	* if (value != null)
1108	<	*   map.put(key, value);
1109	<	* else
1110	<	*   value = map.get(key);
1111	<	* return value;}</pre>
1665	>	*  map.put(key, remappingFunction.remap(key, map.get(key));
1666	>	* }</pre>
1667		*
1668	<	* except that the action is performed atomically.  Some attempted
1668	>	* except that the action is performed atomically.  If the
1669	>	* function returns {@code null} (in which case a {@code
1670	>	* NullPointerException} is thrown), or the function itself throws
1671	>	* an (unchecked) exception, the exception is rethrown to its
1672	>	* caller, and current mapping is left unchanged.  Some attempted
1673		* update operations on this map by other threads may be blocked
1674		* while computation is in progress, so the computation should be
1675		* short and simple, and must not attempt to update any other
1676	<	* mappings of this Map.
1676	>	* mappings of this Map. For example, to either create or
1677	>	* append new messages to a value mapping:
1678	>	*
1679	>	* <pre> {@code
1680	>	* Map<Key, String> map = ...;
1681	>	* final String msg = ...;
1682	>	* map.compute(key, new RemappingFunction<Key, String>() {
1683	>	*   public String remap(Key k, String v) {
1684	>	*    return (v == null) ? msg : v + msg;});}}</pre>
1685		*
1686		* @param key key with which the specified value is to be associated
1687	<	* @param mappingFunction the function to compute a value
1688	<	* @return the current value associated with
1689	<	*         the specified key, or {@code null} if the computation
1690	<	*         returned {@code null} and the value was not otherwise present.
1691	<	* @throws NullPointerException if the specified key or mappingFunction
1125	<	*         is null,
1687	>	* @param remappingFunction the function to compute a value
1688	>	* @return the new value associated with
1689	>	*         the specified key.
1690	>	* @throws NullPointerException if the specified key or remappingFunction
1691	>	*         or computed value is null
1692		* @throws IllegalStateException if the computation detectably
1693		*         attempts a recursive update to this map that would
1694	<	*         otherwise never complete.
1695	<	* @throws RuntimeException or Error if the mappingFunction does so,
1696	<	*         in which case the mapping is unchanged.
1694	>	*         otherwise never complete
1695	>	* @throws RuntimeException or Error if the remappingFunction does so,
1696	>	*         in which case the mapping is unchanged
1697		*/
1698	<	public V compute(K key, MappingFunction<? super K, ? extends V> mappingFunction) {
1699	<	if (key == null || mappingFunction == null)
1698	>	@SuppressWarnings("unchecked")
1699	>	public V compute(K key, RemappingFunction<? super K, V> remappingFunction) {
1700	>	if (key == null || remappingFunction == null)
1701		throw new NullPointerException();
1702	<	return internalCompute(key, mappingFunction, true);
1702	>	return (V)internalCompute(key, remappingFunction);
1703		}
1704
1705		/**
#	Line 1428 | Line 1995 | public class ConcurrentHashMapV8<K, V>
1995		Object k = nextKey;
1996		Object v = nextVal;
1997		advance();
1998	<	return new WriteThroughEntry<K,V>(map, (K)k, (V)v);
1998	>	return new WriteThroughEntry<K,V>((K)k, (V)v, map);
1999	>	}
2000	>	}
2001	>
2002	>	static final class SnapshotEntryIterator<K,V> extends ViewIterator<K,V>
2003	>	implements Iterator<Map.Entry<K,V>> {
2004	>	SnapshotEntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2005	>
2006	>	@SuppressWarnings("unchecked")
2007	>	public final Map.Entry<K,V> next() {
2008	>	if (next == null)
2009	>	throw new NoSuchElementException();
2010	>	Object k = nextKey;
2011	>	Object v = nextVal;
2012	>	advance();
2013	>	return new SnapshotEntry<K,V>((K)k, (V)v);
2014		}
2015		}
2016
2017		/**
2018	<	* Custom Entry class used by EntryIterator.next(), that relays
1437	<	* setValue changes to the underlying map.
2018	>	* Base of writeThrough and Snapshot entry classes
2019		*/
2020	<	static final class WriteThroughEntry<K,V> implements Map.Entry<K, V> {
1440	<	final ConcurrentHashMapV8<K, V> map;
2020	>	static abstract class MapEntry<K,V> implements Map.Entry<K, V> {
2021		final K key; // non-null
2022		V val;       // non-null
2023	<	WriteThroughEntry(ConcurrentHashMapV8<K, V> map, K key, V val) {
1444	<	this.map = map; this.key = key; this.val = val;
1445	<	}
1446	<
2023	>	MapEntry(K key, V val)        { this.key = key; this.val = val; }
2024		public final K getKey()       { return key; }
2025		public final V getValue()     { return val; }
2026		public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
#	Line 1458 | Line 2035 | public class ConcurrentHashMapV8<K, V>
2035		(v == val || v.equals(val)));
2036		}
2037
2038	+	public abstract V setValue(V value);
2039	+	}
2040	+
2041	+	/**
2042	+	* Entry used by EntryIterator.next(), that relays setValue
2043	+	* changes to the underlying map.
2044	+	*/
2045	+	static final class WriteThroughEntry<K,V> extends MapEntry<K,V>
2046	+	implements Map.Entry<K, V> {
2047	+	final ConcurrentHashMapV8<K, V> map;
2048	+	WriteThroughEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
2049	+	super(key, val);
2050	+	this.map = map;
2051	+	}
2052	+
2053		/**
2054		* Sets our entry's value and writes through to the map. The
2055		* value to return is somewhat arbitrary here. Since a
#	Line 1476 | Line 2068 | public class ConcurrentHashMapV8<K, V>
2068		}
2069		}
2070
2071	+	/**
2072	+	* Internal version of entry, that doesn't write though changes
2073	+	*/
2074	+	static final class SnapshotEntry<K,V> extends MapEntry<K,V>
2075	+	implements Map.Entry<K, V> {
2076	+	SnapshotEntry(K key, V val) { super(key, val); }
2077	+	public final V setValue(V value) { // only locally update
2078	+	if (value == null) throw new NullPointerException();
2079	+	V v = val;
2080	+	val = value;
2081	+	return v;
2082	+	}
2083	+	}
2084	+
2085		/* ----------------Views -------------- */
2086
2087	<	/*
2088	<	* These currently just extend java.util.AbstractX classes, but
2089	<	* may need a new custom base to support partitioned traversal.
2087	>	/**
2088	>	* Base class for views. This is done mainly to allow adding
2089	>	* customized parallel traversals (not yet implemented.)
2090		*/
2091	<
1486	<	static final class KeySet<K,V> extends AbstractSet<K> {
2091	>	static abstract class MapView<K, V> {
2092		final ConcurrentHashMapV8<K, V> map;
2093	<	KeySet(ConcurrentHashMapV8<K, V> map)   { this.map = map; }
1489	<
2093	>	MapView(ConcurrentHashMapV8<K, V> map)  { this.map = map; }
2094		public final int size()                 { return map.size(); }
2095		public final boolean isEmpty()          { return map.isEmpty(); }
2096		public final void clear()               { map.clear(); }
2097	+
2098	+	// implementations below rely on concrete classes supplying these
2099	+	abstract Iterator<?> iter();
2100	+	abstract public boolean contains(Object o);
2101	+	abstract public boolean remove(Object o);
2102	+
2103	+	private static final String oomeMsg = "Required array size too large";
2104	+
2105	+	public final Object[] toArray() {
2106	+	long sz = map.longSize();
2107	+	if (sz > (long)(MAX_ARRAY_SIZE))
2108	+	throw new OutOfMemoryError(oomeMsg);
2109	+	int n = (int)sz;
2110	+	Object[] r = new Object[n];
2111	+	int i = 0;
2112	+	Iterator<?> it = iter();
2113	+	while (it.hasNext()) {
2114	+	if (i == n) {
2115	+	if (n >= MAX_ARRAY_SIZE)
2116	+	throw new OutOfMemoryError(oomeMsg);
2117	+	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
2118	+	n = MAX_ARRAY_SIZE;
2119	+	else
2120	+	n += (n >>> 1) + 1;
2121	+	r = Arrays.copyOf(r, n);
2122	+	}
2123	+	r[i++] = it.next();
2124	+	}
2125	+	return (i == n) ? r : Arrays.copyOf(r, i);
2126	+	}
2127	+
2128	+	@SuppressWarnings("unchecked")
2129	+	public final <T> T[] toArray(T[] a) {
2130	+	long sz = map.longSize();
2131	+	if (sz > (long)(MAX_ARRAY_SIZE))
2132	+	throw new OutOfMemoryError(oomeMsg);
2133	+	int m = (int)sz;
2134	+	T[] r = (a.length >= m) ? a :
2135	+	(T[])java.lang.reflect.Array
2136	+	.newInstance(a.getClass().getComponentType(), m);
2137	+	int n = r.length;
2138	+	int i = 0;
2139	+	Iterator<?> it = iter();
2140	+	while (it.hasNext()) {
2141	+	if (i == n) {
2142	+	if (n >= MAX_ARRAY_SIZE)
2143	+	throw new OutOfMemoryError(oomeMsg);
2144	+	if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
2145	+	n = MAX_ARRAY_SIZE;
2146	+	else
2147	+	n += (n >>> 1) + 1;
2148	+	r = Arrays.copyOf(r, n);
2149	+	}
2150	+	r[i++] = (T)it.next();
2151	+	}
2152	+	if (a == r && i < n) {
2153	+	r[i] = null; // null-terminate
2154	+	return r;
2155	+	}
2156	+	return (i == n) ? r : Arrays.copyOf(r, i);
2157	+	}
2158	+
2159	+	public final int hashCode() {
2160	+	int h = 0;
2161	+	for (Iterator<?> it = iter(); it.hasNext();)
2162	+	h += it.next().hashCode();
2163	+	return h;
2164	+	}
2165	+
2166	+	public final String toString() {
2167	+	StringBuilder sb = new StringBuilder();
2168	+	sb.append('[');
2169	+	Iterator<?> it = iter();
2170	+	if (it.hasNext()) {
2171	+	for (;;) {
2172	+	Object e = it.next();
2173	+	sb.append(e == this ? "(this Collection)" : e);
2174	+	if (!it.hasNext())
2175	+	break;
2176	+	sb.append(',').append(' ');
2177	+	}
2178	+	}
2179	+	return sb.append(']').toString();
2180	+	}
2181	+
2182	+	public final boolean containsAll(Collection<?> c) {
2183	+	if (c != this) {
2184	+	for (Iterator<?> it = c.iterator(); it.hasNext();) {
2185	+	Object e = it.next();
2186	+	if (e == null || !contains(e))
2187	+	return false;
2188	+	}
2189	+	}
2190	+	return true;
2191	+	}
2192	+
2193	+	public final boolean removeAll(Collection<?> c) {
2194	+	boolean modified = false;
2195	+	for (Iterator<?> it = iter(); it.hasNext();) {
2196	+	if (c.contains(it.next())) {
2197	+	it.remove();
2198	+	modified = true;
2199	+	}
2200	+	}
2201	+	return modified;
2202	+	}
2203	+
2204	+	public final boolean retainAll(Collection<?> c) {
2205	+	boolean modified = false;
2206	+	for (Iterator<?> it = iter(); it.hasNext();) {
2207	+	if (!c.contains(it.next())) {
2208	+	it.remove();
2209	+	modified = true;
2210	+	}
2211	+	}
2212	+	return modified;
2213	+	}
2214	+
2215	+	}
2216	+
2217	+	static final class KeySet<K,V> extends MapView<K,V> implements Set<K> {
2218	+	KeySet(ConcurrentHashMapV8<K, V> map)   { super(map); }
2219		public final boolean contains(Object o) { return map.containsKey(o); }
2220		public final boolean remove(Object o)   { return map.remove(o) != null; }
2221	+
2222		public final Iterator<K> iterator() {
2223		return new KeyIterator<K,V>(map);
2224		}
2225	+	final Iterator<?> iter() {
2226	+	return new KeyIterator<K,V>(map);
2227	+	}
2228	+	public final boolean add(K e) {
2229	+	throw new UnsupportedOperationException();
2230	+	}
2231	+	public final boolean addAll(Collection<? extends K> c) {
2232	+	throw new UnsupportedOperationException();
2233	+	}
2234	+	public boolean equals(Object o) {
2235	+	Set<?> c;
2236	+	return ((o instanceof Set) &&
2237	+	((c = (Set<?>)o) == this ||
2238	+	(containsAll(c) && c.containsAll(this))));
2239	+	}
2240		}
2241
2242	<	static final class Values<K,V> extends AbstractCollection<V> {
2243	<	final ConcurrentHashMapV8<K, V> map;
2244	<	Values(ConcurrentHashMapV8<K, V> map)   { this.map = map; }
1503	<
1504	<	public final int size()                 { return map.size(); }
1505	<	public final boolean isEmpty()          { return map.isEmpty(); }
1506	<	public final void clear()               { map.clear(); }
2242	>	static final class Values<K,V> extends MapView<K,V>
2243	>	implements Collection<V> {
2244	>	Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
2245		public final boolean contains(Object o) { return map.containsValue(o); }
2246	+
2247	+	public final boolean remove(Object o) {
2248	+	if (o != null) {
2249	+	Iterator<V> it = new ValueIterator<K,V>(map);
2250	+	while (it.hasNext()) {
2251	+	if (o.equals(it.next())) {
2252	+	it.remove();
2253	+	return true;
2254	+	}
2255	+	}
2256	+	}
2257	+	return false;
2258	+	}
2259		public final Iterator<V> iterator() {
2260		return new ValueIterator<K,V>(map);
2261		}
2262	+	final Iterator<?> iter() {
2263	+	return new ValueIterator<K,V>(map);
2264	+	}
2265	+	public final boolean add(V e) {
2266	+	throw new UnsupportedOperationException();
2267	+	}
2268	+	public final boolean addAll(Collection<? extends V> c) {
2269	+	throw new UnsupportedOperationException();
2270	+	}
2271		}
2272
2273	<	static final class EntrySet<K,V> extends AbstractSet<Map.Entry<K,V>> {
2274	<	final ConcurrentHashMapV8<K, V> map;
2275	<	EntrySet(ConcurrentHashMapV8<K, V> map) { this.map = map; }
1516	<
1517	<	public final int size()                 { return map.size(); }
1518	<	public final boolean isEmpty()          { return map.isEmpty(); }
1519	<	public final void clear()               { map.clear(); }
1520	<	public final Iterator<Map.Entry<K,V>> iterator() {
1521	<	return new EntryIterator<K,V>(map);
1522	<	}
2273	>	static final class EntrySet<K,V> extends MapView<K,V>
2274	>	implements Set<Map.Entry<K,V>> {
2275	>	EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
2276
2277		public final boolean contains(Object o) {
2278		Object k, v, r; Map.Entry<?,?> e;
#	Line 1537 | Line 2290 | public class ConcurrentHashMapV8<K, V>
2290		(v = e.getValue()) != null &&
2291		map.remove(k, v));
2292		}
2293	+
2294	+	public final Iterator<Map.Entry<K,V>> iterator() {
2295	+	return new EntryIterator<K,V>(map);
2296	+	}
2297	+	final Iterator<?> iter() {
2298	+	return new SnapshotEntryIterator<K,V>(map);
2299	+	}
2300	+	public final boolean add(Entry<K,V> e) {
2301	+	throw new UnsupportedOperationException();
2302	+	}
2303	+	public final boolean addAll(Collection<? extends Entry<K,V>> c) {
2304	+	throw new UnsupportedOperationException();
2305	+	}
2306	+	public boolean equals(Object o) {
2307	+	Set<?> c;
2308	+	return ((o instanceof Set) &&
2309	+	((c = (Set<?>)o) == this ||
2310	+	(containsAll(c) && c.containsAll(this))));
2311	+	}
2312		}
2313
2314		/* ---------------- Serialization Support -------------- */
#	Line 1567 | Line 2339 | public class ConcurrentHashMapV8<K, V>
2339		segments = (Segment<K,V>[])
2340		new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL];
2341		for (int i = 0; i < segments.length; ++i)
2342	<	segments[i] = new Segment<K,V>(DEFAULT_LOAD_FACTOR);
2342	>	segments[i] = new Segment<K,V>(LOAD_FACTOR);
2343		}
2344		s.defaultWriteObject();
2345		InternalIterator it = new InternalIterator(table);
#	Line 1590 | Line 2362 | public class ConcurrentHashMapV8<K, V>
2362		throws java.io.IOException, ClassNotFoundException {
2363		s.defaultReadObject();
2364		this.segments = null; // unneeded
2365	<	// initalize transient final fields
2365	>	// initialize transient final field
2366		UNSAFE.putObjectVolatile(this, counterOffset, new LongAdder());
1595	–	UNSAFE.putFloatVolatile(this, loadFactorOffset, DEFAULT_LOAD_FACTOR);
1596	–	this.targetCapacity = DEFAULT_CAPACITY;
2367
2368		// Create all nodes, then place in table once size is known
2369		long size = 0L;
#	Line 1610 | Line 2380 | public class ConcurrentHashMapV8<K, V>
2380		}
2381		if (p != null) {
2382		boolean init = false;
2383	<	if (resizing == 0 &&
2384	<	UNSAFE.compareAndSwapInt(this, resizingOffset, 0, 1)) {
2383	>	int n;
2384	>	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
2385	>	n = MAXIMUM_CAPACITY;
2386	>	else {
2387	>	int sz = (int)size;
2388	>	n = tableSizeFor(sz + (sz >>> 1) + 1);
2389	>	}
2390	>	int sc = sizeCtl;
2391	>	if (n > sc &&
2392	>	UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
2393		try {
2394		if (table == null) {
2395		init = true;
1618	–	int n;
1619	–	if (size >= (long)(MAXIMUM_CAPACITY >>> 1))
1620	–	n = MAXIMUM_CAPACITY;
1621	–	else {
1622	–	int sz = (int)size;
1623	–	n = tableSizeFor(sz + (sz >>> 1));
1624	–	}
1625	–	threshold = (n - (n >>> 2)) - THRESHOLD_OFFSET;
2396		Node[] tab = new Node[n];
2397		int mask = n - 1;
2398		while (p != null) {
#	Line 1634 | Line 2404 | public class ConcurrentHashMapV8<K, V>
2404		}
2405		table = tab;
2406		counter.add(size);
2407	+	sc = n - (n >>> 2);
2408		}
2409		} finally {
2410	<	resizing = 0;
2410	>	sizeCtl = sc;
2411		}
2412		}
2413		if (!init) { // Can only happen if unsafely published.
2414		while (p != null) {
2415	<	internalPut(p.key, p.val, true);
2415	>	internalPut(p.key, p.val);
2416		p = p.next;
2417		}
2418		}
#	Line 1651 | Line 2422 | public class ConcurrentHashMapV8<K, V>
2422		// Unsafe mechanics
2423		private static final sun.misc.Unsafe UNSAFE;
2424		private static final long counterOffset;
2425	<	private static final long loadFactorOffset;
1655	<	private static final long resizingOffset;
2425	>	private static final long sizeCtlOffset;
2426		private static final long ABASE;
2427		private static final int ASHIFT;
2428
#	Line 1663 | Line 2433 | public class ConcurrentHashMapV8<K, V>
2433		Class<?> k = ConcurrentHashMapV8.class;
2434		counterOffset = UNSAFE.objectFieldOffset
2435		(k.getDeclaredField("counter"));
2436	<	loadFactorOffset = UNSAFE.objectFieldOffset
2437	<	(k.getDeclaredField("loadFactor"));
1668	<	resizingOffset = UNSAFE.objectFieldOffset
1669	<	(k.getDeclaredField("resizing"));
2436	>	sizeCtlOffset = UNSAFE.objectFieldOffset
2437	>	(k.getDeclaredField("sizeCtl"));
2438		Class<?> sc = Node[].class;
2439		ABASE = UNSAFE.arrayBaseOffset(sc);
2440		ss = UNSAFE.arrayIndexScale(sc);

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