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Comparing jsr166/src/jsr166e/ConcurrentHashMapV8.java (file contents):
Revision 1.34 by jsr166, Mon Dec 19 19:18:35 2011 UTC vs.
Revision 1.46 by dl, Thu Jul 5 18:05:28 2012 UTC

#	Line 20 | Line 20 | import java.util.Enumeration;
20		import java.util.ConcurrentModificationException;
21		import java.util.NoSuchElementException;
22		import java.util.concurrent.ConcurrentMap;
23	+	import java.util.concurrent.ThreadLocalRandom;
24		import java.util.concurrent.locks.LockSupport;
25	+	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
26		import java.io.Serializable;
27
28		/**
#	Line 103 | Line 105 | public class ConcurrentHashMapV8<K, V>
105		*/
106		public static interface MappingFunction<K, V> {
107		/**
108	<	* Returns a non-null value for the given key.
108	>	* Returns a value for the given key, or null if there is no mapping.
109		*
110		* @param key the (non-null) key
111	<	* @return a non-null value
111	>	* @return a value for the key, or null if none
112		*/
113		V map(K key);
114		}
#	Line 123 | Line 125 | public class ConcurrentHashMapV8<K, V>
125		*
126		* @param key the (non-null) key
127		* @param value the current value, or null if there is no mapping
128	<	* @return a non-null value
128	>	* @return a value for the key, or null if none
129		*/
130		V remap(K key, V value);
131		}
132
133	+	/**
134	+	* A partitionable iterator. A Spliterator can be traversed
135	+	* directly, but can also be partitioned (before traversal) by
136	+	* creating another Spliterator that covers a non-overlapping
137	+	* portion of the elements, and so may be amenable to parallel
138	+	* execution.
139	+	*
140	+	* <p> This interface exports a subset of expected JDK8
141	+	* functionality.
142	+	*
143	+	* <p>Sample usage: Here is one (of the several) ways to compute
144	+	* the sum of the values held in a map using the ForkJoin
145	+	* framework. As illustrated here, Spliterators are well suited to
146	+	* designs in which a task repeatedly splits off half its work
147	+	* into forked subtasks until small enough to process directly,
148	+	* and then joins these subtasks. Variants of this style can also
149	+	* be used in completion-based designs.
150	+	*
151	+	* <pre>
152	+	* {@code ConcurrentHashMapV8<String, Long> m = ...
153	+	* // Uses parallel depth of log2 of size / (parallelism * slack of 8).
154	+	* int depth = 32 - Integer.numberOfLeadingZeros(m.size() / (aForkJoinPool.getParallelism() * 8));
155	+	* long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), depth, null));
156	+	* // ...
157	+	* static class SumValues extends RecursiveTask<Long> {
158	+	*   final Spliterator<Long> s;
159	+	*   final int depth;             // number of splits before processing
160	+	*   final SumValues nextJoin;    // records forked subtasks to join
161	+	*   SumValues(Spliterator<Long> s, int depth, SumValues nextJoin) {
162	+	*     this.s = s; this.depth = depth; this.nextJoin = nextJoin;
163	+	*   }
164	+	*   public Long compute() {
165	+	*     long sum = 0;
166	+	*     SumValues subtasks = null; // fork subtasks
167	+	*     for (int d = depth - 1; d >= 0; --d)
168	+	*       (subtasks = new SumValues(s.split(), d, subtasks)).fork();
169	+	*     while (s.hasNext())        // directly process remaining elements
170	+	*       sum += s.next();
171	+	*     for (SumValues t = subtasks; t != null; t = t.nextJoin)
172	+	*       sum += t.join();         // collect subtask results
173	+	*     return sum;
174	+	*   }
175	+	* }
176	+	* }</pre>
177	+	*/
178	+	public static interface Spliterator<T> extends Iterator<T> {
179	+	/**
180	+	* Returns a Spliterator covering approximately half of the
181	+	* elements, guaranteed not to overlap with those subsequently
182	+	* returned by this Spliterator.  After invoking this method,
183	+	* the current Spliterator will <em>not</em> produce any of
184	+	* the elements of the returned Spliterator, but the two
185	+	* Spliterators together will produce all of the elements that
186	+	* would have been produced by this Spliterator had this
187	+	* method not been called. The exact number of elements
188	+	* produced by the returned Spliterator is not guaranteed, and
189	+	* may be zero (i.e., with {@code hasNext()} reporting {@code
190	+	* false}) if this Spliterator cannot be further split.
191	+	*
192	+	* @return a Spliterator covering approximately half of the
193	+	* elements
194	+	* @throws IllegalStateException if this Spliterator has
195	+	* already commenced traversing elements
196	+	*/
197	+	Spliterator<T> split();
198	+	}
199	+
200		/*
201		* Overview:
202		*
#	Line 147 | Line 216 | public class ConcurrentHashMapV8<K, V>
216		* supplying null-checks and casts as needed. This also allows
217		* many of the public methods to be factored into a smaller number
218		* of internal methods (although sadly not so for the five
219	<	* sprawling variants of put-related operations).
219	>	* variants of put-related operations). The validation-based
220	>	* approach explained below leads to a lot of code sprawl because
221	>	* retry-control precludes factoring into smaller methods.
222		*
223		* The table is lazily initialized to a power-of-two size upon the
224	<	* first insertion.  Each bin in the table contains a list of
225	<	* Nodes (most often, the list has only zero or one Node).  Table
226	<	* accesses require volatile/atomic reads, writes, and CASes.
227	<	* Because there is no other way to arrange this without adding
228	<	* further indirections, we use intrinsics (sun.misc.Unsafe)
229	<	* operations.  The lists of nodes within bins are always
230	<	* accurately traversable under volatile reads, so long as lookups
231	<	* check hash code and non-nullness of value before checking key
232	<	* equality.
224	>	* first insertion.  Each bin in the table normally contains a
225	>	* list of Nodes (most often, the list has only zero or one Node).
226	>	* Table accesses require volatile/atomic reads, writes, and
227	>	* CASes.  Because there is no other way to arrange this without
228	>	* adding further indirections, we use intrinsics
229	>	* (sun.misc.Unsafe) operations.  The lists of nodes within bins
230	>	* are always accurately traversable under volatile reads, so long
231	>	* as lookups check hash code and non-nullness of value before
232	>	* checking key equality.
233		*
234		* We use the top two bits of Node hash fields for control
235		* purposes -- they are available anyway because of addressing
#	Line 170 | Line 241 | public class ConcurrentHashMapV8<K, V>
241		*  10 - Node is a forwarding node
242		*
243		* The lower 30 bits of each Node's hash field contain a
244	<	* transformation (for better randomization -- method "spread") of
245	<	* the key's hash code, except for forwarding nodes, for which the
246	<	* lower bits are zero (and so always have hash field == MOVED).
244	>	* transformation of the key's hash code, except for forwarding
245	>	* nodes, for which the lower bits are zero (and so always have
246	>	* hash field == MOVED).
247		*
248		* Insertion (via put or its variants) of the first node in an
249		* empty bin is performed by just CASing it to the bin.  This is
250	<	* by far the most common case for put operations.  Other update
251	<	* operations (insert, delete, and replace) require locks.  We do
252	<	* not want to waste the space required to associate a distinct
253	<	* lock object with each bin, so instead use the first node of a
254	<	* bin list itself as a lock. Blocking support for these locks
255	<	* relies on the builtin "synchronized" monitors.  However, we
256	<	* also need a tryLock construction, so we overlay these by using
257	<	* bits of the Node hash field for lock control (see above), and
258	<	* so normally use builtin monitors only for blocking and
259	<	* signalling using wait/notifyAll constructions. See
260	<	* Node.tryAwaitLock.
250	>	* by far the most common case for put operations under most
251	>	* key/hash distributions.  Other update operations (insert,
252	>	* delete, and replace) require locks.  We do not want to waste
253	>	* the space required to associate a distinct lock object with
254	>	* each bin, so instead use the first node of a bin list itself as
255	>	* a lock. Blocking support for these locks relies on the builtin
256	>	* "synchronized" monitors.  However, we also need a tryLock
257	>	* construction, so we overlay these by using bits of the Node
258	>	* hash field for lock control (see above), and so normally use
259	>	* builtin monitors only for blocking and signalling using
260	>	* wait/notifyAll constructions. See Node.tryAwaitLock.
261		*
262		* Using the first node of a list as a lock does not by itself
263		* suffice though: When a node is locked, any update must first
#	Line 201 | Line 272 | public class ConcurrentHashMapV8<K, V>
272		* The main disadvantage of per-bin locks is that other update
273		* operations on other nodes in a bin list protected by the same
274		* lock can stall, for example when user equals() or mapping
275	<	* functions take a long time.  However, statistically, this is
276	<	* not a common enough problem to outweigh the time/space overhead
277	<	* of alternatives: Under random hash codes, the frequency of
207	<	* nodes in bins follows a Poisson distribution
275	>	* functions take a long time.  However, statistically, under
276	>	* random hash codes, this is not a common problem.  Ideally, the
277	>	* frequency of nodes in bins follows a Poisson distribution
278		* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
279		* parameter of about 0.5 on average, given the resizing threshold
280		* of 0.75, although with a large variance because of resizing
281		* granularity. Ignoring variance, the expected occurrences of
282		* list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The
283	<	* first few values are:
283	>	* first values are:
284		*
285	<	* 0:    0.607
286	<	* 1:    0.303
287	<	* 2:    0.076
288	<	* 3:    0.012
289	<	* more: 0.002
285	>	* 0:    0.60653066
286	>	* 1:    0.30326533
287	>	* 2:    0.07581633
288	>	* 3:    0.01263606
289	>	* 4:    0.00157952
290	>	* 5:    0.00015795
291	>	* 6:    0.00001316
292	>	* 7:    0.00000094
293	>	* 8:    0.00000006
294	>	* more: less than 1 in ten million
295		*
296		* Lock contention probability for two threads accessing distinct
297	<	* elements is roughly 1 / (8 * #elements).  Function "spread"
298	<	* performs hashCode randomization that improves the likelihood
299	<	* that these assumptions hold unless users define exactly the
300	<	* same value for too many hashCodes.
297	>	* elements is roughly 1 / (8 * #elements) under random hashes.
298	>	*
299	>	* Actual hash code distributions encountered in practice
300	>	* sometimes deviate significantly from uniform randomness.  This
301	>	* includes the case when N > (1<<30), so some keys MUST collide.
302	>	* Similarly for dumb or hostile usages in which multiple keys are
303	>	* designed to have identical hash codes. Also, although we guard
304	>	* against the worst effects of this (see method spread), sets of
305	>	* hashes may differ only in bits that do not impact their bin
306	>	* index for a given power-of-two mask.  So we use a secondary
307	>	* strategy that applies when the number of nodes in a bin exceeds
308	>	* a threshold, and at least one of the keys implements
309	>	* Comparable.  These TreeBins use a balanced tree to hold nodes
310	>	* (a specialized form of red-black trees), bounding search time
311	>	* to O(log N).  Each search step in a TreeBin is around twice as
312	>	* slow as in a regular list, but given that N cannot exceed
313	>	* (1<<64) (before running out of addresses) this bounds search
314	>	* steps, lock hold times, etc, to reasonable constants (roughly
315	>	* 100 nodes inspected per operation worst case) so long as keys
316	>	* are Comparable (which is very common -- String, Long, etc).
317	>	* TreeBin nodes (TreeNodes) also maintain the same "next"
318	>	* traversal pointers as regular nodes, so can be traversed in
319	>	* iterators in the same way.
320		*
321	<	* The table is resized when occupancy exceeds an occupancy
321	>	* The table is resized when occupancy exceeds a percentage
322		* threshold (nominally, 0.75, but see below).  Only a single
323		* thread performs the resize (using field "sizeCtl", to arrange
324		* exclusion), but the table otherwise remains usable for reads
#	Line 245 | Line 339 | public class ConcurrentHashMapV8<K, V>
339		*
340		* Each bin transfer requires its bin lock. However, unlike other
341		* cases, a transfer can skip a bin if it fails to acquire its
342	<	* lock, and revisit it later. Method rebuild maintains a buffer
343	<	* of TRANSFER_BUFFER_SIZE bins that have been skipped because of
344	<	* failure to acquire a lock, and blocks only if none are
345	<	* available (i.e., only very rarely).  The transfer operation
346	<	* must also ensure that all accessible bins in both the old and
347	<	* new table are usable by any traversal.  When there are no lock
348	<	* acquisition failures, this is arranged simply by proceeding
349	<	* from the last bin (table.length - 1) up towards the first.
350	<	* Upon seeing a forwarding node, traversals (see class
351	<	* InternalIterator) arrange to move to the new table without
352	<	* revisiting nodes.  However, when any node is skipped during a
353	<	* transfer, all earlier table bins may have become visible, so
354	<	* are initialized with a reverse-forwarding node back to the old
355	<	* table until the new ones are established. (This sometimes
356	<	* requires transiently locking a forwarding node, which is
357	<	* possible under the above encoding.) These more expensive
342	>	* lock, and revisit it later (unless it is a TreeBin). Method
343	>	* rebuild maintains a buffer of TRANSFER_BUFFER_SIZE bins that
344	>	* have been skipped because of failure to acquire a lock, and
345	>	* blocks only if none are available (i.e., only very rarely).
346	>	* The transfer operation must also ensure that all accessible
347	>	* bins in both the old and new table are usable by any traversal.
348	>	* When there are no lock acquisition failures, this is arranged
349	>	* simply by proceeding from the last bin (table.length - 1) up
350	>	* towards the first.  Upon seeing a forwarding node, traversals
351	>	* (see class InternalIterator) arrange to move to the new table
352	>	* without revisiting nodes.  However, when any node is skipped
353	>	* during a transfer, all earlier table bins may have become
354	>	* visible, so are initialized with a reverse-forwarding node back
355	>	* to the old table until the new ones are established. (This
356	>	* sometimes requires transiently locking a forwarding node, which
357	>	* is possible under the above encoding.) These more expensive
358		* mechanics trigger only when necessary.
359		*
360		* The traversal scheme also applies to partial traversals of
361		* ranges of bins (via an alternate InternalIterator constructor)
362	<	* to support partitioned aggregate operations (that are not
363	<	* otherwise implemented yet).  Also, read-only operations give up
364	<	* if ever forwarded to a null table, which provides support for
365	<	* shutdown-style clearing, which is also not currently
272	<	* implemented.
362	>	* to support partitioned aggregate operations.  Also, read-only
363	>	* operations give up if ever forwarded to a null table, which
364	>	* provides support for shutdown-style clearing, which is also not
365	>	* currently implemented.
366		*
367		* Lazy table initialization minimizes footprint until first use,
368		* and also avoids resizings when the first operation is from a
#	Line 347 | Line 440 | public class ConcurrentHashMapV8<K, V>
440		*/
441		private static final int TRANSFER_BUFFER_SIZE = 32;
442
443	+	/**
444	+	* The bin count threshold for using a tree rather than list for a
445	+	* bin.  The value reflects the approximate break-even point for
446	+	* using tree-based operations.
447	+	*/
448	+	private static final int TREE_THRESHOLD = 8;
449	+
450		/*
451		* Encodings for special uses of Node hash fields. See above for
452		* explanation.
453		*/
454	<	static final int MOVED     = 0x80000000; // hash field for fowarding nodes
454	>	static final int MOVED     = 0x80000000; // hash field for forwarding nodes
455		static final int LOCKED    = 0x40000000; // set/tested only as a bit
456		static final int WAITING   = 0xc0000000; // both bits set/tested together
457		static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
#	Line 386 | Line 486 | public class ConcurrentHashMapV8<K, V>
486		/** For serialization compatibility. Null unless serialized; see below */
487		private Segment<K,V>[] segments;
488
489	+	/* ---------------- Table element access -------------- */
490	+
491	+	/*
492	+	* Volatile access methods are used for table elements as well as
493	+	* elements of in-progress next table while resizing.  Uses are
494	+	* null checked by callers, and implicitly bounds-checked, relying
495	+	* on the invariants that tab arrays have non-zero size, and all
496	+	* indices are masked with (tab.length - 1) which is never
497	+	* negative and always less than length. Note that, to be correct
498	+	* wrt arbitrary concurrency errors by users, bounds checks must
499	+	* operate on local variables, which accounts for some odd-looking
500	+	* inline assignments below.
501	+	*/
502	+
503	+	static final Node tabAt(Node[] tab, int i) { // used by InternalIterator
504	+	return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
505	+	}
506	+
507	+	private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) {
508	+	return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v);
509	+	}
510	+
511	+	private static final void setTabAt(Node[] tab, int i, Node v) {
512	+	UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
513	+	}
514	+
515		/* ---------------- Nodes -------------- */
516
517		/**
518		* Key-value entry. Note that this is never exported out as a
519	<	* user-visible Map.Entry (see WriteThroughEntry and SnapshotEntry
520	<	* below). Nodes with a hash field of MOVED are special, and do
521	<	* not contain user keys or values.  Otherwise, keys are never
522	<	* null, and null val fields indicate that a node is in the
523	<	* process of being deleted or created. For purposes of read-only
524	<	* access, a key may be read before a val, but can only be used
525	<	* after checking val to be non-null.
519	>	* user-visible Map.Entry (see MapEntry below). Nodes with a hash
520	>	* field of MOVED are special, and do not contain user keys or
521	>	* values.  Otherwise, keys are never null, and null val fields
522	>	* indicate that a node is in the process of being deleted or
523	>	* created. For purposes of read-only access, a key may be read
524	>	* before a val, but can only be used after checking val to be
525	>	* non-null.
526		*/
527	<	static final class Node {
527	>	static class Node {
528		volatile int hash;
529		final Object key;
530		volatile Object val;
#	Line 435 | Line 561 | public class ConcurrentHashMapV8<K, V>
561		*/
562		final void tryAwaitLock(Node[] tab, int i) {
563		if (tab != null && i >= 0 && i < tab.length) { // bounds check
564	+	int r = ThreadLocalRandom.current().nextInt(); // randomize spins
565		int spins = MAX_SPINS, h;
566		while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
567		if (spins >= 0) {
568	<	if (--spins == MAX_SPINS >>> 1)
569	<	Thread.yield();  // heuristically yield mid-way
568	>	r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
569	>	if (r >= 0 && --spins == 0)
570	>	Thread.yield();  // yield before block
571		}
572		else if (casHash(h, h | WAITING)) {
573		synchronized (this) {
#	Line 476 | Line 604 | public class ConcurrentHashMapV8<K, V>
604		}
605		}
606
607	<	/* ---------------- Table element access -------------- */
607	>	/* ---------------- TreeBins -------------- */
608
609	<	/*
610	<	* Volatile access methods are used for table elements as well as
483	<	* elements of in-progress next table while resizing.  Uses are
484	<	* null checked by callers, and implicitly bounds-checked, relying
485	<	* on the invariants that tab arrays have non-zero size, and all
486	<	* indices are masked with (tab.length - 1) which is never
487	<	* negative and always less than length. Note that, to be correct
488	<	* wrt arbitrary concurrency errors by users, bounds checks must
489	<	* operate on local variables, which accounts for some odd-looking
490	<	* inline assignments below.
609	>	/**
610	>	* Nodes for use in TreeBins
611		*/
612	<
613	<	static final Node tabAt(Node[] tab, int i) { // used by InternalIterator
614	<	return (Node)UNSAFE.getObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE);
612	>	static final class TreeNode extends Node {
613	>	TreeNode parent;  // red-black tree links
614	>	TreeNode left;
615	>	TreeNode right;
616	>	TreeNode prev;    // needed to unlink next upon deletion
617	>	boolean red;
618	>
619	>	TreeNode(int hash, Object key, Object val, Node next, TreeNode parent) {
620	>	super(hash, key, val, next);
621	>	this.parent = parent;
622	>	}
623		}
624
625	<	private static final boolean casTabAt(Node[] tab, int i, Node c, Node v) {
626	<	return UNSAFE.compareAndSwapObject(tab, ((long)i<<ASHIFT)+ABASE, c, v);
627	<	}
625	>	/**
626	>	* A specialized form of red-black tree for use in bins
627	>	* whose size exceeds a threshold.
628	>	*
629	>	* TreeBins use a special form of comparison for search and
630	>	* related operations (which is the main reason we cannot use
631	>	* existing collections such as TreeMaps). TreeBins contain
632	>	* Comparable elements, but may contain others, as well as
633	>	* elements that are Comparable but not necessarily Comparable<T>
634	>	* for the same T, so we cannot invoke compareTo among them. To
635	>	* handle this, the tree is ordered primarily by hash value, then
636	>	* by getClass().getName() order, and then by Comparator order
637	>	* among elements of the same class.  On lookup at a node, if
638	>	* elements are not comparable or compare as 0, both left and
639	>	* right children may need to be searched in the case of tied hash
640	>	* values. (This corresponds to the full list search that would be
641	>	* necessary if all elements were non-Comparable and had tied
642	>	* hashes.)  The red-black balancing code is updated from
643	>	* pre-jdk-collections
644	>	* (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java)
645	>	* based in turn on Cormen, Leiserson, and Rivest "Introduction to
646	>	* Algorithms" (CLR).
647	>	*
648	>	* TreeBins also maintain a separate locking discipline than
649	>	* regular bins. Because they are forwarded via special MOVED
650	>	* nodes at bin heads (which can never change once established),
651	>	* we cannot use use those nodes as locks. Instead, TreeBin
652	>	* extends AbstractQueuedSynchronizer to support a simple form of
653	>	* read-write lock. For update operations and table validation,
654	>	* the exclusive form of lock behaves in the same way as bin-head
655	>	* locks. However, lookups use shared read-lock mechanics to allow
656	>	* multiple readers in the absence of writers.  Additionally,
657	>	* these lookups do not ever block: While the lock is not
658	>	* available, they proceed along the slow traversal path (via
659	>	* next-pointers) until the lock becomes available or the list is
660	>	* exhausted, whichever comes first. (These cases are not fast,
661	>	* but maximize aggregate expected throughput.)  The AQS mechanics
662	>	* for doing this are straightforward.  The lock state is held as
663	>	* AQS getState().  Read counts are negative; the write count (1)
664	>	* is positive.  There are no signalling preferences among readers
665	>	* and writers. Since we don't need to export full Lock API, we
666	>	* just override the minimal AQS methods and use them directly.
667	>	*/
668	>	static final class TreeBin extends AbstractQueuedSynchronizer {
669	>	private static final long serialVersionUID = 2249069246763182397L;
670	>	transient TreeNode root;  // root of tree
671	>	transient TreeNode first; // head of next-pointer list
672
673	<	private static final void setTabAt(Node[] tab, int i, Node v) {
674	<	UNSAFE.putObjectVolatile(tab, ((long)i<<ASHIFT)+ABASE, v);
675	<	}
673	>	/* AQS overrides */
674	>	public final boolean isHeldExclusively() { return getState() > 0; }
675	>	public final boolean tryAcquire(int ignore) {
676	>	if (compareAndSetState(0, 1)) {
677	>	setExclusiveOwnerThread(Thread.currentThread());
678	>	return true;
679	>	}
680	>	return false;
681	>	}
682	>	public final boolean tryRelease(int ignore) {
683	>	setExclusiveOwnerThread(null);
684	>	setState(0);
685	>	return true;
686	>	}
687	>	public final int tryAcquireShared(int ignore) {
688	>	for (int c;;) {
689	>	if ((c = getState()) > 0)
690	>	return -1;
691	>	if (compareAndSetState(c, c -1))
692	>	return 1;
693	>	}
694	>	}
695	>	public final boolean tryReleaseShared(int ignore) {
696	>	int c;
697	>	do {} while (!compareAndSetState(c = getState(), c + 1));
698	>	return c == -1;
699	>	}
700	>
701	>	/** From CLR */
702	>	private void rotateLeft(TreeNode p) {
703	>	if (p != null) {
704	>	TreeNode r = p.right, pp, rl;
705	>	if ((rl = p.right = r.left) != null)
706	>	rl.parent = p;
707	>	if ((pp = r.parent = p.parent) == null)
708	>	root = r;
709	>	else if (pp.left == p)
710	>	pp.left = r;
711	>	else
712	>	pp.right = r;
713	>	r.left = p;
714	>	p.parent = r;
715	>	}
716	>	}
717
718	<	/* ---------------- Internal access and update methods -------------- */
718	>	/** From CLR */
719	>	private void rotateRight(TreeNode p) {
720	>	if (p != null) {
721	>	TreeNode l = p.left, pp, lr;
722	>	if ((lr = p.left = l.right) != null)
723	>	lr.parent = p;
724	>	if ((pp = l.parent = p.parent) == null)
725	>	root = l;
726	>	else if (pp.right == p)
727	>	pp.right = l;
728	>	else
729	>	pp.left = l;
730	>	l.right = p;
731	>	p.parent = l;
732	>	}
733	>	}
734
735	<	/**
736	<	* Applies a supplemental hash function to a given hashCode, which
737	<	* defends against poor quality hash functions.  The result must
738	<	* be have the top 2 bits clear. For reasonable performance, this
739	<	* function must have good avalanche properties; i.e., that each
740	<	* bit of the argument affects each bit of the result. (Although
741	<	* we don't care about the unused top 2 bits.)
735	>	/**
736	>	* Return the TreeNode (or null if not found) for the given key
737	>	* starting at given root.
738	>	*/
739	>	@SuppressWarnings("unchecked") // suppress Comparable cast warning
740	>	final TreeNode getTreeNode(int h, Object k, TreeNode p) {
741	>	Class<?> c = k.getClass();
742	>	while (p != null) {
743	>	int dir, ph;  Object pk; Class<?> pc;
744	>	if ((ph = p.hash) == h) {
745	>	if ((pk = p.key) == k || k.equals(pk))
746	>	return p;
747	>	if (c != (pc = pk.getClass()) ||
748	>	!(k instanceof Comparable) ||
749	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
750	>	dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
751	>	TreeNode r = null, s = null, pl, pr;
752	>	if (dir >= 0) {
753	>	if ((pl = p.left) != null && h <= pl.hash)
754	>	s = pl;
755	>	}
756	>	else if ((pr = p.right) != null && h >= pr.hash)
757	>	s = pr;
758	>	if (s != null && (r = getTreeNode(h, k, s)) != null)
759	>	return r;
760	>	}
761	>	}
762	>	else
763	>	dir = (h < ph) ? -1 : 1;
764	>	p = (dir > 0) ? p.right : p.left;
765	>	}
766	>	return null;
767	>	}
768	>
769	>	/**
770	>	* Wrapper for getTreeNode used by CHM.get. Tries to obtain
771	>	* read-lock to call getTreeNode, but during failure to get
772	>	* lock, searches along next links.
773	>	*/
774	>	final Object getValue(int h, Object k) {
775	>	Node r = null;
776	>	int c = getState(); // Must read lock state first
777	>	for (Node e = first; e != null; e = e.next) {
778	>	if (c <= 0 && compareAndSetState(c, c - 1)) {
779	>	try {
780	>	r = getTreeNode(h, k, root);
781	>	} finally {
782	>	releaseShared(0);
783	>	}
784	>	break;
785	>	}
786	>	else if ((e.hash & HASH_BITS) == h && k.equals(e.key)) {
787	>	r = e;
788	>	break;
789	>	}
790	>	else
791	>	c = getState();
792	>	}
793	>	return r == null ? null : r.val;
794	>	}
795	>
796	>	/**
797	>	* Finds or adds a node.
798	>	* @return null if added
799	>	*/
800	>	@SuppressWarnings("unchecked") // suppress Comparable cast warning
801	>	final TreeNode putTreeNode(int h, Object k, Object v) {
802	>	Class<?> c = k.getClass();
803	>	TreeNode pp = root, p = null;
804	>	int dir = 0;
805	>	while (pp != null) { // find existing node or leaf to insert at
806	>	int ph;  Object pk; Class<?> pc;
807	>	p = pp;
808	>	if ((ph = p.hash) == h) {
809	>	if ((pk = p.key) == k || k.equals(pk))
810	>	return p;
811	>	if (c != (pc = pk.getClass()) ||
812	>	!(k instanceof Comparable) ||
813	>	(dir = ((Comparable)k).compareTo((Comparable)pk)) == 0) {
814	>	dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName());
815	>	TreeNode r = null, s = null, pl, pr;
816	>	if (dir >= 0) {
817	>	if ((pl = p.left) != null && h <= pl.hash)
818	>	s = pl;
819	>	}
820	>	else if ((pr = p.right) != null && h >= pr.hash)
821	>	s = pr;
822	>	if (s != null && (r = getTreeNode(h, k, s)) != null)
823	>	return r;
824	>	}
825	>	}
826	>	else
827	>	dir = (h < ph) ? -1 : 1;
828	>	pp = (dir > 0) ? p.right : p.left;
829	>	}
830	>
831	>	TreeNode f = first;
832	>	TreeNode x = first = new TreeNode(h, k, v, f, p);
833	>	if (p == null)
834	>	root = x;
835	>	else { // attach and rebalance; adapted from CLR
836	>	TreeNode xp, xpp;
837	>	if (f != null)
838	>	f.prev = x;
839	>	if (dir <= 0)
840	>	p.left = x;
841	>	else
842	>	p.right = x;
843	>	x.red = true;
844	>	while (x != null && (xp = x.parent) != null && xp.red &&
845	>	(xpp = xp.parent) != null) {
846	>	TreeNode xppl = xpp.left;
847	>	if (xp == xppl) {
848	>	TreeNode y = xpp.right;
849	>	if (y != null && y.red) {
850	>	y.red = false;
851	>	xp.red = false;
852	>	xpp.red = true;
853	>	x = xpp;
854	>	}
855	>	else {
856	>	if (x == xp.right) {
857	>	rotateLeft(x = xp);
858	>	xpp = (xp = x.parent) == null ? null : xp.parent;
859	>	}
860	>	if (xp != null) {
861	>	xp.red = false;
862	>	if (xpp != null) {
863	>	xpp.red = true;
864	>	rotateRight(xpp);
865	>	}
866	>	}
867	>	}
868	>	}
869	>	else {
870	>	TreeNode y = xppl;
871	>	if (y != null && y.red) {
872	>	y.red = false;
873	>	xp.red = false;
874	>	xpp.red = true;
875	>	x = xpp;
876	>	}
877	>	else {
878	>	if (x == xp.left) {
879	>	rotateRight(x = xp);
880	>	xpp = (xp = x.parent) == null ? null : xp.parent;
881	>	}
882	>	if (xp != null) {
883	>	xp.red = false;
884	>	if (xpp != null) {
885	>	xpp.red = true;
886	>	rotateLeft(xpp);
887	>	}
888	>	}
889	>	}
890	>	}
891	>	}
892	>	TreeNode r = root;
893	>	if (r != null && r.red)
894	>	r.red = false;
895	>	}
896	>	return null;
897	>	}
898	>
899	>	/**
900	>	* Removes the given node, that must be present before this
901	>	* call.  This is messier than typical red-black deletion code
902	>	* because we cannot swap the contents of an interior node
903	>	* with a leaf successor that is pinned by "next" pointers
904	>	* that are accessible independently of lock. So instead we
905	>	* swap the tree linkages.
906	>	*/
907	>	final void deleteTreeNode(TreeNode p) {
908	>	TreeNode next = (TreeNode)p.next; // unlink traversal pointers
909	>	TreeNode pred = p.prev;
910	>	if (pred == null)
911	>	first = next;
912	>	else
913	>	pred.next = next;
914	>	if (next != null)
915	>	next.prev = pred;
916	>	TreeNode replacement;
917	>	TreeNode pl = p.left;
918	>	TreeNode pr = p.right;
919	>	if (pl != null && pr != null) {
920	>	TreeNode s = pr, sl;
921	>	while ((sl = s.left) != null) // find successor
922	>	s = sl;
923	>	boolean c = s.red; s.red = p.red; p.red = c; // swap colors
924	>	TreeNode sr = s.right;
925	>	TreeNode pp = p.parent;
926	>	if (s == pr) { // p was s's direct parent
927	>	p.parent = s;
928	>	s.right = p;
929	>	}
930	>	else {
931	>	TreeNode sp = s.parent;
932	>	if ((p.parent = sp) != null) {
933	>	if (s == sp.left)
934	>	sp.left = p;
935	>	else
936	>	sp.right = p;
937	>	}
938	>	if ((s.right = pr) != null)
939	>	pr.parent = s;
940	>	}
941	>	p.left = null;
942	>	if ((p.right = sr) != null)
943	>	sr.parent = p;
944	>	if ((s.left = pl) != null)
945	>	pl.parent = s;
946	>	if ((s.parent = pp) == null)
947	>	root = s;
948	>	else if (p == pp.left)
949	>	pp.left = s;
950	>	else
951	>	pp.right = s;
952	>	replacement = sr;
953	>	}
954	>	else
955	>	replacement = (pl != null) ? pl : pr;
956	>	TreeNode pp = p.parent;
957	>	if (replacement == null) {
958	>	if (pp == null) {
959	>	root = null;
960	>	return;
961	>	}
962	>	replacement = p;
963	>	}
964	>	else {
965	>	replacement.parent = pp;
966	>	if (pp == null)
967	>	root = replacement;
968	>	else if (p == pp.left)
969	>	pp.left = replacement;
970	>	else
971	>	pp.right = replacement;
972	>	p.left = p.right = p.parent = null;
973	>	}
974	>	if (!p.red) { // rebalance, from CLR
975	>	TreeNode x = replacement;
976	>	while (x != null) {
977	>	TreeNode xp, xpl;
978	>	if (x.red || (xp = x.parent) == null) {
979	>	x.red = false;
980	>	break;
981	>	}
982	>	if (x == (xpl = xp.left)) {
983	>	TreeNode sib = xp.right;
984	>	if (sib != null && sib.red) {
985	>	sib.red = false;
986	>	xp.red = true;
987	>	rotateLeft(xp);
988	>	sib = (xp = x.parent) == null ? null : xp.right;
989	>	}
990	>	if (sib == null)
991	>	x = xp;
992	>	else {
993	>	TreeNode sl = sib.left, sr = sib.right;
994	>	if ((sr == null || !sr.red) &&
995	>	(sl == null || !sl.red)) {
996	>	sib.red = true;
997	>	x = xp;
998	>	}
999	>	else {
1000	>	if (sr == null || !sr.red) {
1001	>	if (sl != null)
1002	>	sl.red = false;
1003	>	sib.red = true;
1004	>	rotateRight(sib);
1005	>	sib = (xp = x.parent) == null ? null : xp.right;
1006	>	}
1007	>	if (sib != null) {
1008	>	sib.red = (xp == null) ? false : xp.red;
1009	>	if ((sr = sib.right) != null)
1010	>	sr.red = false;
1011	>	}
1012	>	if (xp != null) {
1013	>	xp.red = false;
1014	>	rotateLeft(xp);
1015	>	}
1016	>	x = root;
1017	>	}
1018	>	}
1019	>	}
1020	>	else { // symmetric
1021	>	TreeNode sib = xpl;
1022	>	if (sib != null && sib.red) {
1023	>	sib.red = false;
1024	>	xp.red = true;
1025	>	rotateRight(xp);
1026	>	sib = (xp = x.parent) == null ? null : xp.left;
1027	>	}
1028	>	if (sib == null)
1029	>	x = xp;
1030	>	else {
1031	>	TreeNode sl = sib.left, sr = sib.right;
1032	>	if ((sl == null || !sl.red) &&
1033	>	(sr == null || !sr.red)) {
1034	>	sib.red = true;
1035	>	x = xp;
1036	>	}
1037	>	else {
1038	>	if (sl == null || !sl.red) {
1039	>	if (sr != null)
1040	>	sr.red = false;
1041	>	sib.red = true;
1042	>	rotateLeft(sib);
1043	>	sib = (xp = x.parent) == null ? null : xp.left;
1044	>	}
1045	>	if (sib != null) {
1046	>	sib.red = (xp == null) ? false : xp.red;
1047	>	if ((sl = sib.left) != null)
1048	>	sl.red = false;
1049	>	}
1050	>	if (xp != null) {
1051	>	xp.red = false;
1052	>	rotateRight(xp);
1053	>	}
1054	>	x = root;
1055	>	}
1056	>	}
1057	>	}
1058	>	}
1059	>	}
1060	>	if (p == replacement && (pp = p.parent) != null) {
1061	>	if (p == pp.left) // detach pointers
1062	>	pp.left = null;
1063	>	else if (p == pp.right)
1064	>	pp.right = null;
1065	>	p.parent = null;
1066	>	}
1067	>	}
1068	>	}
1069	>
1070	>	/* ---------------- Collision reduction methods -------------- */
1071	>
1072	>	/**
1073	>	* Spreads higher bits to lower, and also forces top 2 bits to 0.
1074	>	* Because the table uses power-of-two masking, sets of hashes
1075	>	* that vary only in bits above the current mask will always
1076	>	* collide. (Among known examples are sets of Float keys holding
1077	>	* consecutive whole numbers in small tables.)  To counter this,
1078	>	* we apply a transform that spreads the impact of higher bits
1079	>	* downward. There is a tradeoff between speed, utility, and
1080	>	* quality of bit-spreading. Because many common sets of hashes
1081	>	* are already reasonably distributed across bits (so don't benefit
1082	>	* from spreading), and because we use trees to handle large sets
1083	>	* of collisions in bins, we don't need excessively high quality.
1084		*/
1085		private static final int spread(int h) {
1086	<	// Apply base step of MurmurHash; see http://code.google.com/p/smhasher/
1087	<	// Despite two multiplies, this is often faster than others
1088	<	// with comparable bit-spread properties.
1089	<	h ^= h >>> 16;
1090	<	h *= 0x85ebca6b;
1091	<	h ^= h >>> 13;
1092	<	h *= 0xc2b2ae35;
1093	<	return ((h >>> 16) ^ h) & HASH_BITS; // mask out top bits
1086	>	h ^= (h >>> 18) ^ (h >>> 12);
1087	>	return (h ^ (h >>> 10)) & HASH_BITS;
1088	>	}
1089	>
1090	>	/**
1091	>	* Replaces a list bin with a tree bin. Call only when locked.
1092	>	* Fails to replace if the given key is non-comparable or table
1093	>	* is, or needs, resizing.
1094	>	*/
1095	>	private final void replaceWithTreeBin(Node[] tab, int index, Object key) {
1096	>	if ((key instanceof Comparable) &&
1097	>	(tab.length >= MAXIMUM_CAPACITY || counter.sum() < (long)sizeCtl)) {
1098	>	TreeBin t = new TreeBin();
1099	>	for (Node e = tabAt(tab, index); e != null; e = e.next)
1100	>	t.putTreeNode(e.hash & HASH_BITS, e.key, e.val);
1101	>	setTabAt(tab, index, new Node(MOVED, t, null, null));
1102	>	}
1103		}
1104
1105	+	/* ---------------- Internal access and update methods -------------- */
1106	+
1107		/** Implementation for get and containsKey */
1108		private final Object internalGet(Object k) {
1109		int h = spread(k.hashCode());
1110		retry: for (Node[] tab = table; tab != null;) {
1111	<	Node e; Object ek, ev; int eh;    // locals to read fields once
1111	>	Node e, p; Object ek, ev; int eh;      // locals to read fields once
1112		for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
1113		if ((eh = e.hash) == MOVED) {
1114	<	tab = (Node[])e.key;      // restart with new table
1115	<	continue retry;
1114	>	if ((ek = e.key) instanceof TreeBin)  // search TreeBin
1115	>	return ((TreeBin)ek).getValue(h, k);
1116	>	else {                        // restart with new table
1117	>	tab = (Node[])ek;
1118	>	continue retry;
1119	>	}
1120		}
1121	<	if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
1122	<	((ek = e.key) == k || k.equals(ek)))
1121	>	else if ((eh & HASH_BITS) == h && (ev = e.val) != null &&
1122	>	((ek = e.key) == k || k.equals(ek)))
1123		return ev;
1124		}
1125		break;
#	Line 551 | Line 1136 | public class ConcurrentHashMapV8<K, V>
1136		int h = spread(k.hashCode());
1137		Object oldVal = null;
1138		for (Node[] tab = table;;) {
1139	<	Node f; int i, fh;
1139	>	Node f; int i, fh; Object fk;
1140		if (tab == null ||
1141		(f = tabAt(tab, i = (tab.length - 1) & h)) == null)
1142		break;
1143	<	else if ((fh = f.hash) == MOVED)
1144	<	tab = (Node[])f.key;
1143	>	else if ((fh = f.hash) == MOVED) {
1144	>	if ((fk = f.key) instanceof TreeBin) {
1145	>	TreeBin t = (TreeBin)fk;
1146	>	boolean validated = false;
1147	>	boolean deleted = false;
1148	>	t.acquire(0);
1149	>	try {
1150	>	if (tabAt(tab, i) == f) {
1151	>	validated = true;
1152	>	TreeNode p = t.getTreeNode(h, k, t.root);
1153	>	if (p != null) {
1154	>	Object pv = p.val;
1155	>	if (cv == null || cv == pv || cv.equals(pv)) {
1156	>	oldVal = pv;
1157	>	if ((p.val = v) == null) {
1158	>	deleted = true;
1159	>	t.deleteTreeNode(p);
1160	>	}
1161	>	}
1162	>	}
1163	>	}
1164	>	} finally {
1165	>	t.release(0);
1166	>	}
1167	>	if (validated) {
1168	>	if (deleted)
1169	>	counter.add(-1L);
1170	>	break;
1171	>	}
1172	>	}
1173	>	else
1174	>	tab = (Node[])fk;
1175	>	}
1176		else if ((fh & HASH_BITS) != h && f.next == null) // precheck
1177		break;                          // rules out possible existence
1178		else if ((fh & LOCKED) != 0) {
#	Line 615 | Line 1231 | public class ConcurrentHashMapV8<K, V>
1231		*  1. If table uninitialized, create
1232		*  2. If bin empty, try to CAS new node
1233		*  3. If bin stale, use new table
1234	<	*  4. Lock and validate; if valid, scan and add or update
1234	>	*  4. if bin converted to TreeBin, validate and relay to TreeBin methods
1235	>	*  5. Lock and validate; if valid, scan and add or update
1236		*
1237		* The others interweave other checks and/or alternative actions:
1238		*  * Plain put checks for and performs resize after insertion.
#	Line 636 | Line 1253 | public class ConcurrentHashMapV8<K, V>
1253		/** Implementation for put */
1254		private final Object internalPut(Object k, Object v) {
1255		int h = spread(k.hashCode());
1256	<	boolean checkSize = false;
1256	>	int count = 0;
1257		for (Node[] tab = table;;) {
1258	<	int i; Node f; int fh;
1258	>	int i; Node f; int fh; Object fk;
1259		if (tab == null)
1260		tab = initTable();
1261		else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1262		if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1263		break;                   // no lock when adding to empty bin
1264		}
1265	<	else if ((fh = f.hash) == MOVED)
1266	<	tab = (Node[])f.key;
1265	>	else if ((fh = f.hash) == MOVED) {
1266	>	if ((fk = f.key) instanceof TreeBin) {
1267	>	TreeBin t = (TreeBin)fk;
1268	>	Object oldVal = null;
1269	>	t.acquire(0);
1270	>	try {
1271	>	if (tabAt(tab, i) == f) {
1272	>	count = 2;
1273	>	TreeNode p = t.putTreeNode(h, k, v);
1274	>	if (p != null) {
1275	>	oldVal = p.val;
1276	>	p.val = v;
1277	>	}
1278	>	}
1279	>	} finally {
1280	>	t.release(0);
1281	>	}
1282	>	if (count != 0) {
1283	>	if (oldVal != null)
1284	>	return oldVal;
1285	>	break;
1286	>	}
1287	>	}
1288	>	else
1289	>	tab = (Node[])fk;
1290	>	}
1291		else if ((fh & LOCKED) != 0) {
1292		checkForResize();
1293		f.tryAwaitLock(tab, i);
1294		}
1295		else if (f.casHash(fh, fh | LOCKED)) {
1296		Object oldVal = null;
656	–	boolean validated = false;
1297		try {                        // needed in case equals() throws
1298		if (tabAt(tab, i) == f) {
1299	<	validated = true;    // retry if 1st already deleted
1300	<	for (Node e = f;;) {
1299	>	count = 1;
1300	>	for (Node e = f;; ++count) {
1301		Object ek, ev;
1302		if ((e.hash & HASH_BITS) == h &&
1303		(ev = e.val) != null &&
#	Line 669 | Line 1309 | public class ConcurrentHashMapV8<K, V>
1309		Node last = e;
1310		if ((e = e.next) == null) {
1311		last.next = new Node(h, k, v, null);
1312	<	if (last != f || tab.length <= 64)
1313	<	checkSize = true;
1312	>	if (count >= TREE_THRESHOLD)
1313	>	replaceWithTreeBin(tab, i, k);
1314		break;
1315		}
1316		}
#	Line 681 | Line 1321 | public class ConcurrentHashMapV8<K, V>
1321		synchronized (f) { f.notifyAll(); };
1322		}
1323		}
1324	<	if (validated) {
1324	>	if (count != 0) {
1325		if (oldVal != null)
1326		return oldVal;
1327	+	if (tab.length <= 64)
1328	+	count = 2;
1329		break;
1330		}
1331		}
1332		}
1333		counter.add(1L);
1334	<	if (checkSize)
1334	>	if (count > 1)
1335		checkForResize();
1336		return null;
1337		}
#	Line 697 | Line 1339 | public class ConcurrentHashMapV8<K, V>
1339		/** Implementation for putIfAbsent */
1340		private final Object internalPutIfAbsent(Object k, Object v) {
1341		int h = spread(k.hashCode());
1342	+	int count = 0;
1343		for (Node[] tab = table;;) {
1344		int i; Node f; int fh; Object fk, fv;
1345		if (tab == null)
#	Line 705 | Line 1348 | public class ConcurrentHashMapV8<K, V>
1348		if (casTabAt(tab, i, null, new Node(h, k, v, null)))
1349		break;
1350		}
1351	<	else if ((fh = f.hash) == MOVED)
1352	<	tab = (Node[])f.key;
1351	>	else if ((fh = f.hash) == MOVED) {
1352	>	if ((fk = f.key) instanceof TreeBin) {
1353	>	TreeBin t = (TreeBin)fk;
1354	>	Object oldVal = null;
1355	>	t.acquire(0);
1356	>	try {
1357	>	if (tabAt(tab, i) == f) {
1358	>	count = 2;
1359	>	TreeNode p = t.putTreeNode(h, k, v);
1360	>	if (p != null)
1361	>	oldVal = p.val;
1362	>	}
1363	>	} finally {
1364	>	t.release(0);
1365	>	}
1366	>	if (count != 0) {
1367	>	if (oldVal != null)
1368	>	return oldVal;
1369	>	break;
1370	>	}
1371	>	}
1372	>	else
1373	>	tab = (Node[])fk;
1374	>	}
1375		else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1376		((fk = f.key) == k || k.equals(fk)))
1377		return fv;
#	Line 730 | Line 1395 | public class ConcurrentHashMapV8<K, V>
1395		}
1396		else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1397		Object oldVal = null;
733	–	boolean validated = false;
1398		try {
1399		if (tabAt(tab, i) == f) {
1400	<	validated = true;
1401	<	for (Node e = f;;) {
1400	>	count = 1;
1401	>	for (Node e = f;; ++count) {
1402		Object ek, ev;
1403		if ((e.hash & HASH_BITS) == h &&
1404		(ev = e.val) != null &&
#	Line 745 | Line 1409 | public class ConcurrentHashMapV8<K, V>
1409		Node last = e;
1410		if ((e = e.next) == null) {
1411		last.next = new Node(h, k, v, null);
1412	+	if (count >= TREE_THRESHOLD)
1413	+	replaceWithTreeBin(tab, i, k);
1414		break;
1415		}
1416		}
#	Line 755 | Line 1421 | public class ConcurrentHashMapV8<K, V>
1421		synchronized (f) { f.notifyAll(); };
1422		}
1423		}
1424	<	if (validated) {
1424	>	if (count != 0) {
1425		if (oldVal != null)
1426		return oldVal;
1427	+	if (tab.length <= 64)
1428	+	count = 2;
1429		break;
1430		}
1431		}
1432		}
1433		}
1434		counter.add(1L);
1435	+	if (count > 1)
1436	+	checkForResize();
1437		return null;
1438		}
1439
#	Line 772 | Line 1442 | public class ConcurrentHashMapV8<K, V>
1442		MappingFunction<? super K, ?> mf) {
1443		int h = spread(k.hashCode());
1444		Object val = null;
1445	+	int count = 0;
1446		for (Node[] tab = table;;) {
1447		Node f; int i, fh; Object fk, fv;
1448		if (tab == null)
1449		tab = initTable();
1450		else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1451		Node node = new Node(fh = h | LOCKED, k, null, null);
781	–	boolean validated = false;
1452		if (casTabAt(tab, i, null, node)) {
1453	<	validated = true;
1453	>	count = 1;
1454		try {
1455		if ((val = mf.map(k)) != null)
1456		node.val = val;
#	Line 793 | Line 1463 | public class ConcurrentHashMapV8<K, V>
1463		}
1464		}
1465		}
1466	<	if (validated)
1466	>	if (count != 0)
1467		break;
1468		}
1469	<	else if ((fh = f.hash) == MOVED)
1470	<	tab = (Node[])f.key;
1469	>	else if ((fh = f.hash) == MOVED) {
1470	>	if ((fk = f.key) instanceof TreeBin) {
1471	>	TreeBin t = (TreeBin)fk;
1472	>	boolean added = false;
1473	>	t.acquire(0);
1474	>	try {
1475	>	if (tabAt(tab, i) == f) {
1476	>	count = 1;
1477	>	TreeNode p = t.getTreeNode(h, k, t.root);
1478	>	if (p != null)
1479	>	val = p.val;
1480	>	else if ((val = mf.map(k)) != null) {
1481	>	added = true;
1482	>	count = 2;
1483	>	t.putTreeNode(h, k, val);
1484	>	}
1485	>	}
1486	>	} finally {
1487	>	t.release(0);
1488	>	}
1489	>	if (count != 0) {
1490	>	if (!added)
1491	>	return val;
1492	>	break;
1493	>	}
1494	>	}
1495	>	else
1496	>	tab = (Node[])fk;
1497	>	}
1498		else if ((fh & HASH_BITS) == h && (fv = f.val) != null &&
1499		((fk = f.key) == k || k.equals(fk)))
1500		return fv;
#	Line 820 | Line 1517 | public class ConcurrentHashMapV8<K, V>
1517		f.tryAwaitLock(tab, i);
1518		}
1519		else if (tabAt(tab, i) == f && f.casHash(fh, fh | LOCKED)) {
1520	<	boolean validated = false;
1520	>	boolean added = false;
1521		try {
1522		if (tabAt(tab, i) == f) {
1523	<	validated = true;
1524	<	for (Node e = f;;) {
1523	>	count = 1;
1524	>	for (Node e = f;; ++count) {
1525		Object ek, ev;
1526		if ((e.hash & HASH_BITS) == h &&
1527		(ev = e.val) != null &&
#	Line 834 | Line 1531 | public class ConcurrentHashMapV8<K, V>
1531		}
1532		Node last = e;
1533		if ((e = e.next) == null) {
1534	<	if ((val = mf.map(k)) != null)
1534	>	if ((val = mf.map(k)) != null) {
1535	>	added = true;
1536		last.next = new Node(h, k, val, null);
1537	+	if (count >= TREE_THRESHOLD)
1538	+	replaceWithTreeBin(tab, i, k);
1539	+	}
1540		break;
1541		}
1542		}
#	Line 846 | Line 1547 | public class ConcurrentHashMapV8<K, V>
1547		synchronized (f) { f.notifyAll(); };
1548		}
1549		}
1550	<	if (validated)
1550	>	if (count != 0) {
1551	>	if (!added)
1552	>	return val;
1553	>	if (tab.length <= 64)
1554	>	count = 2;
1555		break;
1556	+	}
1557		}
1558		}
1559		}
1560	<	if (val == null)
1561	<	throw new NullPointerException();
1562	<	counter.add(1L);
1560	>	if (val != null) {
1561	>	counter.add(1L);
1562	>	if (count > 1)
1563	>	checkForResize();
1564	>	}
1565		return val;
1566		}
1567
#	Line 863 | Line 1571 | public class ConcurrentHashMapV8<K, V>
1571		RemappingFunction<? super K, V> mf) {
1572		int h = spread(k.hashCode());
1573		Object val = null;
1574	<	boolean added = false;
1575	<	boolean checkSize = false;
1574	>	int delta = 0;
1575	>	int count = 0;
1576		for (Node[] tab = table;;) {
1577	<	Node f; int i, fh;
1577	>	Node f; int i, fh; Object fk;
1578		if (tab == null)
1579		tab = initTable();
1580		else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
1581		Node node = new Node(fh = h | LOCKED, k, null, null);
874	–	boolean validated = false;
1582		if (casTabAt(tab, i, null, node)) {
876	–	validated = true;
1583		try {
1584	+	count = 1;
1585		if ((val = mf.remap(k, null)) != null) {
1586		node.val = val;
1587	<	added = true;
1587	>	delta = 1;
1588		}
1589		} finally {
1590	<	if (!added)
1590	>	if (delta == 0)
1591		setTabAt(tab, i, null);
1592		if (!node.casHash(fh, h)) {
1593		node.hash = h;
#	Line 888 | Line 1595 | public class ConcurrentHashMapV8<K, V>
1595		}
1596		}
1597		}
1598	<	if (validated)
1598	>	if (count != 0)
1599		break;
1600		}
1601	<	else if ((fh = f.hash) == MOVED)
1602	<	tab = (Node[])f.key;
1601	>	else if ((fh = f.hash) == MOVED) {
1602	>	if ((fk = f.key) instanceof TreeBin) {
1603	>	TreeBin t = (TreeBin)fk;
1604	>	t.acquire(0);
1605	>	try {
1606	>	if (tabAt(tab, i) == f) {
1607	>	count = 1;
1608	>	TreeNode p = t.getTreeNode(h, k, t.root);
1609	>	Object pv = (p == null) ? null : p.val;
1610	>	if ((val = mf.remap(k, (V)pv)) != null) {
1611	>	if (p != null)
1612	>	p.val = val;
1613	>	else {
1614	>	count = 2;
1615	>	delta = 1;
1616	>	t.putTreeNode(h, k, val);
1617	>	}
1618	>	}
1619	>	else if (p != null) {
1620	>	delta = -1;
1621	>	t.deleteTreeNode(p);
1622	>	}
1623	>	}
1624	>	} finally {
1625	>	t.release(0);
1626	>	}
1627	>	if (count != 0)
1628	>	break;
1629	>	}
1630	>	else
1631	>	tab = (Node[])fk;
1632	>	}
1633		else if ((fh & LOCKED) != 0) {
1634		checkForResize();
1635		f.tryAwaitLock(tab, i);
1636		}
1637		else if (f.casHash(fh, fh | LOCKED)) {
901	–	boolean validated = false;
1638		try {
1639		if (tabAt(tab, i) == f) {
1640	<	validated = true;
1641	<	for (Node e = f;;) {
1640	>	count = 1;
1641	>	for (Node e = f, pred = null;; ++count) {
1642		Object ek, ev;
1643		if ((e.hash & HASH_BITS) == h &&
1644		(ev = e.val) != null &&
#	Line 910 | Line 1646 | public class ConcurrentHashMapV8<K, V>
1646		val = mf.remap(k, (V)ev);
1647		if (val != null)
1648		e.val = val;
1649	+	else {
1650	+	delta = -1;
1651	+	Node en = e.next;
1652	+	if (pred != null)
1653	+	pred.next = en;
1654	+	else
1655	+	setTabAt(tab, i, en);
1656	+	}
1657		break;
1658		}
1659	<	Node last = e;
1659	>	pred = e;
1660		if ((e = e.next) == null) {
1661		if ((val = mf.remap(k, null)) != null) {
1662	<	last.next = new Node(h, k, val, null);
1663	<	added = true;
1664	<	if (last != f || tab.length <= 64)
1665	<	checkSize = true;
1662	>	pred.next = new Node(h, k, val, null);
1663	>	delta = 1;
1664	>	if (count >= TREE_THRESHOLD)
1665	>	replaceWithTreeBin(tab, i, k);
1666		}
1667		break;
1668		}
#	Line 930 | Line 1674 | public class ConcurrentHashMapV8<K, V>
1674		synchronized (f) { f.notifyAll(); };
1675		}
1676		}
1677	<	if (validated)
1677	>	if (count != 0) {
1678	>	if (tab.length <= 64)
1679	>	count = 2;
1680		break;
1681	+	}
1682		}
1683		}
1684	<	if (val == null)
1685	<	throw new NullPointerException();
1686	<	if (added) {
940	<	counter.add(1L);
941	<	if (checkSize)
1684	>	if (delta != 0) {
1685	>	counter.add((long)delta);
1686	>	if (count > 1)
1687		checkForResize();
1688		}
1689		return val;
#	Line 959 | Line 1704 | public class ConcurrentHashMapV8<K, V>
1704		}
1705		int h = spread(k.hashCode());
1706		for (Node[] tab = table;;) {
1707	<	int i; Node f; int fh;
1707	>	int i; Node f; int fh; Object fk;
1708		if (tab == null)
1709		tab = initTable();
1710		else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){
#	Line 968 | Line 1713 | public class ConcurrentHashMapV8<K, V>
1713		break;
1714		}
1715		}
1716	<	else if ((fh = f.hash) == MOVED)
1717	<	tab = (Node[])f.key;
1716	>	else if ((fh = f.hash) == MOVED) {
1717	>	if ((fk = f.key) instanceof TreeBin) {
1718	>	TreeBin t = (TreeBin)fk;
1719	>	boolean validated = false;
1720	>	t.acquire(0);
1721	>	try {
1722	>	if (tabAt(tab, i) == f) {
1723	>	validated = true;
1724	>	TreeNode p = t.getTreeNode(h, k, t.root);
1725	>	if (p != null)
1726	>	p.val = v;
1727	>	else {
1728	>	t.putTreeNode(h, k, v);
1729	>	++delta;
1730	>	}
1731	>	}
1732	>	} finally {
1733	>	t.release(0);
1734	>	}
1735	>	if (validated)
1736	>	break;
1737	>	}
1738	>	else
1739	>	tab = (Node[])fk;
1740	>	}
1741		else if ((fh & LOCKED) != 0) {
1742		counter.add(delta);
1743		delta = 0L;
#	Line 977 | Line 1745 | public class ConcurrentHashMapV8<K, V>
1745		f.tryAwaitLock(tab, i);
1746		}
1747		else if (f.casHash(fh, fh | LOCKED)) {
1748	<	boolean validated = false;
981	<	boolean tooLong = false;
1748	>	int count = 0;
1749		try {
1750		if (tabAt(tab, i) == f) {
1751	<	validated = true;
1752	<	for (Node e = f;;) {
1751	>	count = 1;
1752	>	for (Node e = f;; ++count) {
1753		Object ek, ev;
1754		if ((e.hash & HASH_BITS) == h &&
1755		(ev = e.val) != null &&
#	Line 994 | Line 1761 | public class ConcurrentHashMapV8<K, V>
1761		if ((e = e.next) == null) {
1762		++delta;
1763		last.next = new Node(h, k, v, null);
1764	+	if (count >= TREE_THRESHOLD)
1765	+	replaceWithTreeBin(tab, i, k);
1766		break;
1767		}
999	–	tooLong = true;
1768		}
1769		}
1770		} finally {
#	Line 1005 | Line 1773 | public class ConcurrentHashMapV8<K, V>
1773		synchronized (f) { f.notifyAll(); };
1774		}
1775		}
1776	<	if (validated) {
1777	<	if (tooLong) {
1776	>	if (count != 0) {
1777	>	if (count > 1) {
1778		counter.add(delta);
1779		delta = 0L;
1780		checkForResize();
#	Line 1162 | Line 1930 | public class ConcurrentHashMapV8<K, V>
1930		}
1931		}
1932		}
1933	<	else if (((fh = f.hash) & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
1933	>	else if ((fh = f.hash) == MOVED) {
1934	>	Object fk = f.key;
1935	>	if (fk instanceof TreeBin) {
1936	>	TreeBin t = (TreeBin)fk;
1937	>	boolean validated = false;
1938	>	t.acquire(0);
1939	>	try {
1940	>	if (tabAt(tab, i) == f) {
1941	>	validated = true;
1942	>	splitTreeBin(nextTab, i, t);
1943	>	setTabAt(tab, i, fwd);
1944	>	}
1945	>	} finally {
1946	>	t.release(0);
1947	>	}
1948	>	if (!validated)
1949	>	continue;
1950	>	}
1951	>	}
1952	>	else if ((fh & LOCKED) == 0 && f.casHash(fh, fh|LOCKED)) {
1953		boolean validated = false;
1954		try {              // split to lo and hi lists; copying as needed
1955		if (tabAt(tab, i) == f) {
1956		validated = true;
1957	<	Node e = f, lastRun = f;
1171	<	Node lo = null, hi = null;
1172	<	int runBit = e.hash & n;
1173	<	for (Node p = e.next; p != null; p = p.next) {
1174	<	int b = p.hash & n;
1175	<	if (b != runBit) {
1176	<	runBit = b;
1177	<	lastRun = p;
1178	<	}
1179	<	}
1180	<	if (runBit == 0)
1181	<	lo = lastRun;
1182	<	else
1183	<	hi = lastRun;
1184	<	for (Node p = e; p != lastRun; p = p.next) {
1185	<	int ph = p.hash & HASH_BITS;
1186	<	Object pk = p.key, pv = p.val;
1187	<	if ((ph & n) == 0)
1188	<	lo = new Node(ph, pk, pv, lo);
1189	<	else
1190	<	hi = new Node(ph, pk, pv, hi);
1191	<	}
1192	<	setTabAt(nextTab, i, lo);
1193	<	setTabAt(nextTab, i + n, hi);
1957	>	splitBin(nextTab, i, f);
1958		setTabAt(tab, i, fwd);
1959		}
1960		} finally {
#	Line 1236 | Line 2000 | public class ConcurrentHashMapV8<K, V>
2000		}
2001
2002		/**
2003	+	* Splits a normal bin with list headed by e into lo and hi parts;
2004	+	* installs in given table.
2005	+	*/
2006	+	private static void splitBin(Node[] nextTab, int i, Node e) {
2007	+	int bit = nextTab.length >>> 1; // bit to split on
2008	+	int runBit = e.hash & bit;
2009	+	Node lastRun = e, lo = null, hi = null;
2010	+	for (Node p = e.next; p != null; p = p.next) {
2011	+	int b = p.hash & bit;
2012	+	if (b != runBit) {
2013	+	runBit = b;
2014	+	lastRun = p;
2015	+	}
2016	+	}
2017	+	if (runBit == 0)
2018	+	lo = lastRun;
2019	+	else
2020	+	hi = lastRun;
2021	+	for (Node p = e; p != lastRun; p = p.next) {
2022	+	int ph = p.hash & HASH_BITS;
2023	+	Object pk = p.key, pv = p.val;
2024	+	if ((ph & bit) == 0)
2025	+	lo = new Node(ph, pk, pv, lo);
2026	+	else
2027	+	hi = new Node(ph, pk, pv, hi);
2028	+	}
2029	+	setTabAt(nextTab, i, lo);
2030	+	setTabAt(nextTab, i + bit, hi);
2031	+	}
2032	+
2033	+	/**
2034	+	* Splits a tree bin into lo and hi parts; installs in given table.
2035	+	*/
2036	+	private static void splitTreeBin(Node[] nextTab, int i, TreeBin t) {
2037	+	int bit = nextTab.length >>> 1;
2038	+	TreeBin lt = new TreeBin();
2039	+	TreeBin ht = new TreeBin();
2040	+	int lc = 0, hc = 0;
2041	+	for (Node e = t.first; e != null; e = e.next) {
2042	+	int h = e.hash & HASH_BITS;
2043	+	Object k = e.key, v = e.val;
2044	+	if ((h & bit) == 0) {
2045	+	++lc;
2046	+	lt.putTreeNode(h, k, v);
2047	+	}
2048	+	else {
2049	+	++hc;
2050	+	ht.putTreeNode(h, k, v);
2051	+	}
2052	+	}
2053	+	Node ln, hn; // throw away trees if too small
2054	+	if (lc <= (TREE_THRESHOLD >>> 1)) {
2055	+	ln = null;
2056	+	for (Node p = lt.first; p != null; p = p.next)
2057	+	ln = new Node(p.hash, p.key, p.val, ln);
2058	+	}
2059	+	else
2060	+	ln = new Node(MOVED, lt, null, null);
2061	+	setTabAt(nextTab, i, ln);
2062	+	if (hc <= (TREE_THRESHOLD >>> 1)) {
2063	+	hn = null;
2064	+	for (Node p = ht.first; p != null; p = p.next)
2065	+	hn = new Node(p.hash, p.key, p.val, hn);
2066	+	}
2067	+	else
2068	+	hn = new Node(MOVED, ht, null, null);
2069	+	setTabAt(nextTab, i + bit, hn);
2070	+	}
2071	+
2072	+	/**
2073		* Implementation for clear. Steps through each bin, removing all
2074		* nodes.
2075		*/
#	Line 1244 | Line 2078 | public class ConcurrentHashMapV8<K, V>
2078		int i = 0;
2079		Node[] tab = table;
2080		while (tab != null && i < tab.length) {
2081	<	int fh;
2081	>	int fh; Object fk;
2082		Node f = tabAt(tab, i);
2083		if (f == null)
2084		++i;
2085	<	else if ((fh = f.hash) == MOVED)
2086	<	tab = (Node[])f.key;
2085	>	else if ((fh = f.hash) == MOVED) {
2086	>	if ((fk = f.key) instanceof TreeBin) {
2087	>	TreeBin t = (TreeBin)fk;
2088	>	t.acquire(0);
2089	>	try {
2090	>	if (tabAt(tab, i) == f) {
2091	>	for (Node p = t.first; p != null; p = p.next) {
2092	>	p.val = null;
2093	>	--delta;
2094	>	}
2095	>	t.first = null;
2096	>	t.root = null;
2097	>	++i;
2098	>	}
2099	>	} finally {
2100	>	t.release(0);
2101	>	}
2102	>	}
2103	>	else
2104	>	tab = (Node[])fk;
2105	>	}
2106		else if ((fh & LOCKED) != 0) {
2107		counter.add(delta); // opportunistically update count
2108		delta = 0L;
2109		f.tryAwaitLock(tab, i);
2110		}
2111		else if (f.casHash(fh, fh | LOCKED)) {
1259	–	boolean validated = false;
2112		try {
2113		if (tabAt(tab, i) == f) {
1262	–	validated = true;
2114		for (Node e = f; e != null; e = e.next) {
2115	<	if (e.val != null) { // currently always true
2116	<	e.val = null;
1266	<	--delta;
1267	<	}
2115	>	e.val = null;
2116	>	--delta;
2117		}
2118		setTabAt(tab, i, null);
2119	+	++i;
2120		}
2121		} finally {
2122		if (!f.casHash(fh | LOCKED, fh)) {
#	Line 1274 | Line 2124 | public class ConcurrentHashMapV8<K, V>
2124		synchronized (f) { f.notifyAll(); };
2125		}
2126		}
1277	–	if (validated)
1278	–	++i;
2127		}
2128		}
2129		if (delta != 0)
2130		counter.add(delta);
2131		}
2132
1285	–
2133		/* ----------------Table Traversal -------------- */
2134
2135		/**
#	Line 1291 | Line 2138 | public class ConcurrentHashMapV8<K, V>
2138		*
2139		* At each step, the iterator snapshots the key ("nextKey") and
2140		* value ("nextVal") of a valid node (i.e., one that, at point of
2141	<	* snapshot, has a nonnull user value). Because val fields can
2141	>	* snapshot, has a non-null user value). Because val fields can
2142		* change (including to null, indicating deletion), field nextVal
2143		* might not be accurate at point of use, but still maintains the
2144		* weak consistency property of holding a value that was once
2145		* valid.
2146		*
2147		* Internal traversals directly access these fields, as in:
2148	<	* {@code while (it.next != null) { process(it.nextKey); it.advance(); }}
2148	>	* {@code while (it.advance() != null) { process(it.nextKey); }}
2149		*
2150	<	* Exported iterators (subclasses of ViewIterator) extract key,
2151	<	* value, or key-value pairs as return values of Iterator.next(),
2152	<	* and encapsulate the it.next check as hasNext();
2150	>	* Exported iterators must track whether the iterator has advanced
2151	>	* (in hasNext vs next) (by setting/checking/nulling field
2152	>	* nextVal), and then extract key, value, or key-value pairs as
2153	>	* return values of next().
2154		*
2155		* The iterator visits once each still-valid node that was
2156		* reachable upon iterator construction. It might miss some that
#	Line 1320 | Line 2168 | public class ConcurrentHashMapV8<K, V>
2168		* paranoically cope with potential sharing by users of iterators
2169		* across threads, iteration terminates if a bounds checks fails
2170		* for a table read.
1323	–	*
1324	–	* The range-based constructor enables creation of parallel
1325	–	* range-splitting traversals. (Not yet implemented.)
2171		*/
2172	<	static class InternalIterator {
2172	>	static class InternalIterator<K,V> {
2173	>	final ConcurrentHashMapV8<K, V> map;
2174		Node next;           // the next entry to use
2175		Node last;           // the last entry used
2176		Object nextKey;      // cached key field of next
#	Line 1332 | Line 2178 | public class ConcurrentHashMapV8<K, V>
2178		Node[] tab;          // current table; updated if resized
2179		int index;           // index of bin to use next
2180		int baseIndex;       // current index of initial table
2181	<	final int baseLimit; // index bound for initial table
2181	>	int baseLimit;       // index bound for initial table
2182		final int baseSize;  // initial table size
2183
2184		/** Creates iterator for all entries in the table. */
2185	<	InternalIterator(Node[] tab) {
2186	<	this.tab = tab;
2185	>	InternalIterator(ConcurrentHashMapV8<K, V> map) {
2186	>	this.tab = (this.map = map).table;
2187		baseLimit = baseSize = (tab == null) ? 0 : tab.length;
1342	–	index = baseIndex = 0;
1343	–	next = null;
1344	–	advance();
1345	–	}
1346	–
1347	–	/** Creates iterator for the given range of the table */
1348	–	InternalIterator(Node[] tab, int lo, int hi) {
1349	–	this.tab = tab;
1350	–	baseSize = (tab == null) ? 0 : tab.length;
1351	–	baseLimit = (hi <= baseSize) ? hi : baseSize;
1352	–	index = baseIndex = (lo >= 0) ? lo : 0;
1353	–	next = null;
1354	–	advance();
2188		}
2189
2190	<	/** Advances next. See above for explanation. */
2191	<	final void advance() {
2190	>	/** Creates iterator for clone() and split() methods */
2191	>	InternalIterator(InternalIterator<K,V> it, boolean split) {
2192	>	this.map = it.map;
2193	>	this.tab = it.tab;
2194	>	this.baseSize = it.baseSize;
2195	>	int lo = it.baseIndex;
2196	>	int hi = this.baseLimit = it.baseLimit;
2197	>	this.index = this.baseIndex =
2198	>	(split) ? (it.baseLimit = (lo + hi + 1) >>> 1) : lo;
2199	>	}
2200	>
2201	>	/**
2202	>	* Advances next; returns nextVal or null if terminated
2203	>	* See above for explanation.
2204	>	*/
2205	>	final Object advance() {
2206		Node e = last = next;
2207	+	Object ev = null;
2208		outer: do {
2209		if (e != null)                  // advance past used/skipped node
2210		e = e.next;
2211		while (e == null) {             // get to next non-null bin
2212	<	Node[] t; int b, i, n;      // checks must use locals
2212	>	Node[] t; int b, i, n; Object ek; // checks must use locals
2213		if ((b = baseIndex) >= baseLimit || (i = index) < 0 ||
2214		(t = tab) == null || i >= (n = t.length))
2215		break outer;
2216	<	else if ((e = tabAt(t, i)) != null && e.hash == MOVED)
2217	<	tab = (Node[])e.key;    // restarts due to null val
2218	<	else                        // visit upper slots if present
2219	<	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2216	>	else if ((e = tabAt(t, i)) != null && e.hash == MOVED) {
2217	>	if ((ek = e.key) instanceof TreeBin)
2218	>	e = ((TreeBin)ek).first;
2219	>	else {
2220	>	tab = (Node[])ek;
2221	>	continue;           // restarts due to null val
2222	>	}
2223	>	}                           // visit upper slots if present
2224	>	index = (i += baseSize) < n ? i : (baseIndex = b + 1);
2225		}
2226		nextKey = e.key;
2227	<	} while ((nextVal = e.val) == null);// skip deleted or special nodes
2227	>	} while ((ev = e.val) == null);    // skip deleted or special nodes
2228		next = e;
2229	+	return nextVal = ev;
2230		}
2231	+
2232	+	public final void remove() {
2233	+	if (nextVal == null)
2234	+	advance();
2235	+	Node e = last;
2236	+	if (e == null)
2237	+	throw new IllegalStateException();
2238	+	last = null;
2239	+	map.remove(e.key);
2240	+	}
2241	+
2242	+	public final boolean hasNext() {
2243	+	return nextVal != null || advance() != null;
2244	+	}
2245	+
2246	+	public final boolean hasMoreElements() { return hasNext(); }
2247		}
2248
2249		/* ---------------- Public operations -------------- */
#	Line 1535 | Line 2405 | public class ConcurrentHashMapV8<K, V>
2405		if (value == null)
2406		throw new NullPointerException();
2407		Object v;
2408	<	InternalIterator it = new InternalIterator(table);
2409	<	while (it.next != null) {
2410	<	if ((v = it.nextVal) == value || value.equals(v))
2408	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2409	>	while ((v = it.advance()) != null) {
2410	>	if (v == value || value.equals(v))
2411		return true;
1542	–	it.advance();
2412		}
2413		return false;
2414		}
#	Line 1610 | Line 2479 | public class ConcurrentHashMapV8<K, V>
2479
2480		/**
2481		* If the specified key is not already associated with a value,
2482	<	* computes its value using the given mappingFunction and
2483	<	* enters it into the map.  This is equivalent to
2482	>	* computes its value using the given mappingFunction and enters
2483	>	* it into the map unless null.  This is equivalent to
2484		* <pre> {@code
2485		* if (map.containsKey(key))
2486		*   return map.get(key);
2487		* value = mappingFunction.map(key);
2488	<	* map.put(key, value);
2488	>	* if (value != null)
2489	>	*   map.put(key, value);
2490		* return value;}</pre>
2491		*
2492		* except that the action is performed atomically.  If the
2493	<	* function returns {@code null} (in which case a {@code
2494	<	* NullPointerException} is thrown), or the function itself throws
2495	<	* an (unchecked) exception, the exception is rethrown to its
2496	<	* caller, and no mapping is recorded.  Some attempted update
2497	<	* operations on this map by other threads may be blocked while
2498	<	* computation is in progress, so the computation should be short
2499	<	* and simple, and must not attempt to update any other mappings
2500	<	* of this Map. The most appropriate usage is to construct a new
2501	<	* object serving as an initial mapped value, or memoized result,
1632	<	* as in:
2493	>	* function returns {@code null} no mapping is recorded. If the
2494	>	* function itself throws an (unchecked) exception, the exception
2495	>	* is rethrown to its caller, and no mapping is recorded.  Some
2496	>	* attempted update operations on this map by other threads may be
2497	>	* blocked while computation is in progress, so the computation
2498	>	* should be short and simple, and must not attempt to update any
2499	>	* other mappings of this Map. The most appropriate usage is to
2500	>	* construct a new object serving as an initial mapped value, or
2501	>	* memoized result, as in:
2502		*
2503		*  <pre> {@code
2504		* map.computeIfAbsent(key, new MappingFunction<K, V>() {
#	Line 1638 | Line 2507 | public class ConcurrentHashMapV8<K, V>
2507		* @param key key with which the specified value is to be associated
2508		* @param mappingFunction the function to compute a value
2509		* @return the current (existing or computed) value associated with
2510	<	*         the specified key.
2511	<	* @throws NullPointerException if the specified key, mappingFunction,
2512	<	*         or computed value is null
2510	>	*         the specified key, or null if the computed value is null.
2511	>	* @throws NullPointerException if the specified key or mappingFunction
2512	>	*         is null
2513		* @throws IllegalStateException if the computation detectably
2514		*         attempts a recursive update to this map that would
2515		*         otherwise never complete
#	Line 1655 | Line 2524 | public class ConcurrentHashMapV8<K, V>
2524		}
2525
2526		/**
2527	<	* Computes and enters a new mapping value given a key and
2527	>	* Computes a new mapping value given a key and
2528		* its current mapped value (or {@code null} if there is no current
2529		* mapping). This is equivalent to
2530		*  <pre> {@code
2531	<	*  map.put(key, remappingFunction.remap(key, map.get(key));
2531	>	*   value = remappingFunction.remap(key, map.get(key));
2532	>	*   if (value != null)
2533	>	*     map.put(key, value);
2534	>	*   else
2535	>	*     map.remove(key);
2536		* }</pre>
2537		*
2538		* except that the action is performed atomically.  If the
2539	<	* function returns {@code null} (in which case a {@code
2540	<	* NullPointerException} is thrown), or the function itself throws
2541	<	* an (unchecked) exception, the exception is rethrown to its
2542	<	* caller, and current mapping is left unchanged.  Some attempted
2543	<	* update operations on this map by other threads may be blocked
2544	<	* while computation is in progress, so the computation should be
2545	<	* short and simple, and must not attempt to update any other
2546	<	* mappings of this Map. For example, to either create or
1674	<	* append new messages to a value mapping:
2539	>	* function returns {@code null}, the mapping is removed.  If the
2540	>	* function itself throws an (unchecked) exception, the exception
2541	>	* is rethrown to its caller, and the current mapping is left
2542	>	* unchanged.  Some attempted update operations on this map by
2543	>	* other threads may be blocked while computation is in progress,
2544	>	* so the computation should be short and simple, and must not
2545	>	* attempt to update any other mappings of this Map. For example,
2546	>	* to either create or append new messages to a value mapping:
2547		*
2548		* <pre> {@code
2549		* Map<Key, String> map = ...;
#	Line 1683 | Line 2555 | public class ConcurrentHashMapV8<K, V>
2555		* @param key key with which the specified value is to be associated
2556		* @param remappingFunction the function to compute a value
2557		* @return the new value associated with
2558	<	*         the specified key.
2558	>	*         the specified key, or null if none.
2559		* @throws NullPointerException if the specified key or remappingFunction
2560	<	*         or computed value is null
2560	>	*         is null
2561		* @throws IllegalStateException if the computation detectably
2562		*         attempts a recursive update to this map that would
2563		*         otherwise never complete
#	Line 1844 | Line 2716 | public class ConcurrentHashMapV8<K, V>
2716		}
2717
2718		/**
2719	+	* Returns a partionable iterator of the keys in this map.
2720	+	*
2721	+	* @return a partionable iterator of the keys in this map
2722	+	*/
2723	+	public Spliterator<K> keySpliterator() {
2724	+	return new KeyIterator<K,V>(this);
2725	+	}
2726	+
2727	+	/**
2728	+	* Returns a partionable iterator of the values in this map.
2729	+	*
2730	+	* @return a partionable iterator of the values in this map
2731	+	*/
2732	+	public Spliterator<V> valueSpliterator() {
2733	+	return new ValueIterator<K,V>(this);
2734	+	}
2735	+
2736	+	/**
2737	+	* Returns a partionable iterator of the entries in this map.
2738	+	*
2739	+	* @return a partionable iterator of the entries in this map
2740	+	*/
2741	+	public Spliterator<Map.Entry<K,V>> entrySpliterator() {
2742	+	return new EntryIterator<K,V>(this);
2743	+	}
2744	+
2745	+	/**
2746		* Returns the hash code value for this {@link Map}, i.e.,
2747		* the sum of, for each key-value pair in the map,
2748		* {@code key.hashCode() ^ value.hashCode()}.
#	Line 1852 | Line 2751 | public class ConcurrentHashMapV8<K, V>
2751		*/
2752		public int hashCode() {
2753		int h = 0;
2754	<	InternalIterator it = new InternalIterator(table);
2755	<	while (it.next != null) {
2756	<	h += it.nextKey.hashCode() ^ it.nextVal.hashCode();
2757	<	it.advance();
2754	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2755	>	Object v;
2756	>	while ((v = it.advance()) != null) {
2757	>	h += it.nextKey.hashCode() ^ v.hashCode();
2758		}
2759		return h;
2760		}
#	Line 1872 | Line 2771 | public class ConcurrentHashMapV8<K, V>
2771		* @return a string representation of this map
2772		*/
2773		public String toString() {
2774	<	InternalIterator it = new InternalIterator(table);
2774	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2775		StringBuilder sb = new StringBuilder();
2776		sb.append('{');
2777	<	if (it.next != null) {
2777	>	Object v;
2778	>	if ((v = it.advance()) != null) {
2779		for (;;) {
2780	<	Object k = it.nextKey, v = it.nextVal;
2780	>	Object k = it.nextKey;
2781		sb.append(k == this ? "(this Map)" : k);
2782		sb.append('=');
2783		sb.append(v == this ? "(this Map)" : v);
2784	<	it.advance();
1885	<	if (it.next == null)
2784	>	if ((v = it.advance()) == null)
2785		break;
2786		sb.append(',').append(' ');
2787		}
#	Line 1905 | Line 2804 | public class ConcurrentHashMapV8<K, V>
2804		if (!(o instanceof Map))
2805		return false;
2806		Map<?,?> m = (Map<?,?>) o;
2807	<	InternalIterator it = new InternalIterator(table);
2808	<	while (it.next != null) {
2809	<	Object val = it.nextVal;
2807	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
2808	>	Object val;
2809	>	while ((val = it.advance()) != null) {
2810		Object v = m.get(it.nextKey);
2811		if (v == null || (v != val && !v.equals(val)))
2812		return false;
1914	–	it.advance();
2813		}
2814		for (Map.Entry<?,?> e : m.entrySet()) {
2815		Object mk, mv, v;
#	Line 1927 | Line 2825 | public class ConcurrentHashMapV8<K, V>
2825
2826		/* ----------------Iterators -------------- */
2827
2828	<	/**
2829	<	* Base class for key, value, and entry iterators.  Adds a map
2830	<	* reference to InternalIterator to support Iterator.remove.
2831	<	*/
2832	<	static abstract class ViewIterator<K,V> extends InternalIterator {
1935	<	final ConcurrentHashMapV8<K, V> map;
1936	<	ViewIterator(ConcurrentHashMapV8<K, V> map) {
1937	<	super(map.table);
1938	<	this.map = map;
2828	>	static final class KeyIterator<K,V> extends InternalIterator<K,V>
2829	>	implements Spliterator<K>, Enumeration<K> {
2830	>	KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2831	>	KeyIterator(InternalIterator<K,V> it, boolean split) {
2832	>	super(it, split);
2833		}
2834	<
2835	<	public final void remove() {
1942	<	if (last == null)
2834	>	public KeyIterator<K,V> split() {
2835	>	if (last != null || (next != null && nextVal == null))
2836		throw new IllegalStateException();
2837	<	map.remove(last.key);
2838	<	last = null;
2837	>	return new KeyIterator<K,V>(this, true);
2838	>	}
2839	>	public KeyIterator<K,V> clone() {
2840	>	if (last != null || (next != null && nextVal == null))
2841	>	throw new IllegalStateException();
2842	>	return new KeyIterator<K,V>(this, false);
2843		}
1947	–
1948	–	public final boolean hasNext()         { return next != null; }
1949	–	public final boolean hasMoreElements() { return next != null; }
1950	–	}
1951	–
1952	–	static final class KeyIterator<K,V> extends ViewIterator<K,V>
1953	–	implements Iterator<K>, Enumeration<K> {
1954	–	KeyIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2844
2845		@SuppressWarnings("unchecked")
2846		public final K next() {
2847	<	if (next == null)
2847	>	if (nextVal == null && advance() == null)
2848		throw new NoSuchElementException();
2849		Object k = nextKey;
2850	<	advance();
2851	<	return (K)k;
2850	>	nextVal = null;
2851	>	return (K) k;
2852		}
2853
2854		public final K nextElement() { return next(); }
2855		}
2856
2857	<	static final class ValueIterator<K,V> extends ViewIterator<K,V>
2858	<	implements Iterator<V>, Enumeration<V> {
2857	>	static final class ValueIterator<K,V> extends InternalIterator<K,V>
2858	>	implements Spliterator<V>, Enumeration<V> {
2859		ValueIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2860	+	ValueIterator(InternalIterator<K,V> it, boolean split) {
2861	+	super(it, split);
2862	+	}
2863	+	public ValueIterator<K,V> split() {
2864	+	if (last != null || (next != null && nextVal == null))
2865	+	throw new IllegalStateException();
2866	+	return new ValueIterator<K,V>(this, true);
2867	+	}
2868	+
2869	+	public ValueIterator<K,V> clone() {
2870	+	if (last != null || (next != null && nextVal == null))
2871	+	throw new IllegalStateException();
2872	+	return new ValueIterator<K,V>(this, false);
2873	+	}
2874
2875		@SuppressWarnings("unchecked")
2876		public final V next() {
2877	<	if (next == null)
2877	>	Object v;
2878	>	if ((v = nextVal) == null && (v = advance()) == null)
2879		throw new NoSuchElementException();
2880	<	Object v = nextVal;
2881	<	advance();
1978	<	return (V)v;
2880	>	nextVal = null;
2881	>	return (V) v;
2882		}
2883
2884		public final V nextElement() { return next(); }
2885		}
2886
2887	<	static final class EntryIterator<K,V> extends ViewIterator<K,V>
2888	<	implements Iterator<Map.Entry<K,V>> {
2887	>	static final class EntryIterator<K,V> extends InternalIterator<K,V>
2888	>	implements Spliterator<Map.Entry<K,V>> {
2889		EntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2890	<
2891	<	@SuppressWarnings("unchecked")
2892	<	public final Map.Entry<K,V> next() {
2893	<	if (next == null)
2894	<	throw new NoSuchElementException();
2895	<	Object k = nextKey;
2896	<	Object v = nextVal;
2897	<	advance();
2898	<	return new WriteThroughEntry<K,V>((K)k, (V)v, map);
2890	>	EntryIterator(InternalIterator<K,V> it, boolean split) {
2891	>	super(it, split);
2892	>	}
2893	>	public EntryIterator<K,V> split() {
2894	>	if (last != null || (next != null && nextVal == null))
2895	>	throw new IllegalStateException();
2896	>	return new EntryIterator<K,V>(this, true);
2897	>	}
2898	>	public EntryIterator<K,V> clone() {
2899	>	if (last != null || (next != null && nextVal == null))
2900	>	throw new IllegalStateException();
2901	>	return new EntryIterator<K,V>(this, false);
2902		}
1997	–	}
1998	–
1999	–	static final class SnapshotEntryIterator<K,V> extends ViewIterator<K,V>
2000	–	implements Iterator<Map.Entry<K,V>> {
2001	–	SnapshotEntryIterator(ConcurrentHashMapV8<K, V> map) { super(map); }
2903
2904		@SuppressWarnings("unchecked")
2905		public final Map.Entry<K,V> next() {
2906	<	if (next == null)
2906	>	Object v;
2907	>	if ((v = nextVal) == null && (v = advance()) == null)
2908		throw new NoSuchElementException();
2909		Object k = nextKey;
2910	<	Object v = nextVal;
2911	<	advance();
2010	<	return new SnapshotEntry<K,V>((K)k, (V)v);
2910	>	nextVal = null;
2911	>	return new MapEntry<K,V>((K)k, (V)v, map);
2912		}
2913		}
2914
2915		/**
2916	<	* Base of writeThrough and Snapshot entry classes
2916	>	* Exported Entry for iterators
2917		*/
2918	<	static abstract class MapEntry<K,V> implements Map.Entry<K, V> {
2918	>	static final class MapEntry<K,V> implements Map.Entry<K, V> {
2919		final K key; // non-null
2920		V val;       // non-null
2921	<	MapEntry(K key, V val)        { this.key = key; this.val = val; }
2921	>	final ConcurrentHashMapV8<K, V> map;
2922	>	MapEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
2923	>	this.key = key;
2924	>	this.val = val;
2925	>	this.map = map;
2926	>	}
2927		public final K getKey()       { return key; }
2928		public final V getValue()     { return val; }
2929		public final int hashCode()   { return key.hashCode() ^ val.hashCode(); }
#	Line 2032 | Line 2938 | public class ConcurrentHashMapV8<K, V>
2938		(v == val || v.equals(val)));
2939		}
2940
2035	–	public abstract V setValue(V value);
2036	–	}
2037	–
2038	–	/**
2039	–	* Entry used by EntryIterator.next(), that relays setValue
2040	–	* changes to the underlying map.
2041	–	*/
2042	–	static final class WriteThroughEntry<K,V> extends MapEntry<K,V>
2043	–	implements Map.Entry<K, V> {
2044	–	final ConcurrentHashMapV8<K, V> map;
2045	–	WriteThroughEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
2046	–	super(key, val);
2047	–	this.map = map;
2048	–	}
2049	–
2941		/**
2942		* Sets our entry's value and writes through to the map. The
2943	<	* value to return is somewhat arbitrary here. Since a
2944	<	* WriteThroughEntry does not necessarily track asynchronous
2945	<	* changes, the most recent "previous" value could be
2946	<	* different from what we return (or could even have been
2947	<	* removed in which case the put will re-establish). We do not
2057	<	* and cannot guarantee more.
2943	>	* value to return is somewhat arbitrary here. Since a we do
2944	>	* not necessarily track asynchronous changes, the most recent
2945	>	* "previous" value could be different from what we return (or
2946	>	* could even have been removed in which case the put will
2947	>	* re-establish). We do not and cannot guarantee more.
2948		*/
2949		public final V setValue(V value) {
2950		if (value == null) throw new NullPointerException();
#	Line 2065 | Line 2955 | public class ConcurrentHashMapV8<K, V>
2955		}
2956		}
2957
2068	–	/**
2069	–	* Internal version of entry, that doesn't write though changes
2070	–	*/
2071	–	static final class SnapshotEntry<K,V> extends MapEntry<K,V>
2072	–	implements Map.Entry<K, V> {
2073	–	SnapshotEntry(K key, V val) { super(key, val); }
2074	–	public final V setValue(V value) { // only locally update
2075	–	if (value == null) throw new NullPointerException();
2076	–	V v = val;
2077	–	val = value;
2078	–	return v;
2079	–	}
2080	–	}
2081	–
2958		/* ----------------Views -------------- */
2959
2960		/**
2961	<	* Base class for views. This is done mainly to allow adding
2086	<	* customized parallel traversals (not yet implemented.)
2961	>	* Base class for views.
2962		*/
2963		static abstract class MapView<K, V> {
2964		final ConcurrentHashMapV8<K, V> map;
#	Line 2093 | Line 2968 | public class ConcurrentHashMapV8<K, V>
2968		public final void clear()               { map.clear(); }
2969
2970		// implementations below rely on concrete classes supplying these
2971	<	abstract Iterator<?> iter();
2971	>	abstract public Iterator<?> iterator();
2972		abstract public boolean contains(Object o);
2973		abstract public boolean remove(Object o);
2974
#	Line 2106 | Line 2981 | public class ConcurrentHashMapV8<K, V>
2981		int n = (int)sz;
2982		Object[] r = new Object[n];
2983		int i = 0;
2984	<	Iterator<?> it = iter();
2984	>	Iterator<?> it = iterator();
2985		while (it.hasNext()) {
2986		if (i == n) {
2987		if (n >= MAX_ARRAY_SIZE)
#	Line 2133 | Line 3008 | public class ConcurrentHashMapV8<K, V>
3008		.newInstance(a.getClass().getComponentType(), m);
3009		int n = r.length;
3010		int i = 0;
3011	<	Iterator<?> it = iter();
3011	>	Iterator<?> it = iterator();
3012		while (it.hasNext()) {
3013		if (i == n) {
3014		if (n >= MAX_ARRAY_SIZE)
#	Line 2155 | Line 3030 | public class ConcurrentHashMapV8<K, V>
3030
3031		public final int hashCode() {
3032		int h = 0;
3033	<	for (Iterator<?> it = iter(); it.hasNext();)
3033	>	for (Iterator<?> it = iterator(); it.hasNext();)
3034		h += it.next().hashCode();
3035		return h;
3036		}
#	Line 2163 | Line 3038 | public class ConcurrentHashMapV8<K, V>
3038		public final String toString() {
3039		StringBuilder sb = new StringBuilder();
3040		sb.append('[');
3041	<	Iterator<?> it = iter();
3041	>	Iterator<?> it = iterator();
3042		if (it.hasNext()) {
3043		for (;;) {
3044		Object e = it.next();
#	Line 2189 | Line 3064 | public class ConcurrentHashMapV8<K, V>
3064
3065		public final boolean removeAll(Collection<?> c) {
3066		boolean modified = false;
3067	<	for (Iterator<?> it = iter(); it.hasNext();) {
3067	>	for (Iterator<?> it = iterator(); it.hasNext();) {
3068		if (c.contains(it.next())) {
3069		it.remove();
3070		modified = true;
#	Line 2200 | Line 3075 | public class ConcurrentHashMapV8<K, V>
3075
3076		public final boolean retainAll(Collection<?> c) {
3077		boolean modified = false;
3078	<	for (Iterator<?> it = iter(); it.hasNext();) {
3078	>	for (Iterator<?> it = iterator(); it.hasNext();) {
3079		if (!c.contains(it.next())) {
3080		it.remove();
3081		modified = true;
#	Line 2215 | Line 3090 | public class ConcurrentHashMapV8<K, V>
3090		KeySet(ConcurrentHashMapV8<K, V> map)   { super(map); }
3091		public final boolean contains(Object o) { return map.containsKey(o); }
3092		public final boolean remove(Object o)   { return map.remove(o) != null; }
2218	–
3093		public final Iterator<K> iterator() {
3094		return new KeyIterator<K,V>(map);
3095		}
2222	–	final Iterator<?> iter() {
2223	–	return new KeyIterator<K,V>(map);
2224	–	}
3096		public final boolean add(K e) {
3097		throw new UnsupportedOperationException();
3098		}
#	Line 2240 | Line 3111 | public class ConcurrentHashMapV8<K, V>
3111		implements Collection<V> {
3112		Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
3113		public final boolean contains(Object o) { return map.containsValue(o); }
2243	–
3114		public final boolean remove(Object o) {
3115		if (o != null) {
3116		Iterator<V> it = new ValueIterator<K,V>(map);
#	Line 2256 | Line 3126 | public class ConcurrentHashMapV8<K, V>
3126		public final Iterator<V> iterator() {
3127		return new ValueIterator<K,V>(map);
3128		}
2259	–	final Iterator<?> iter() {
2260	–	return new ValueIterator<K,V>(map);
2261	–	}
3129		public final boolean add(V e) {
3130		throw new UnsupportedOperationException();
3131		}
#	Line 2270 | Line 3137 | public class ConcurrentHashMapV8<K, V>
3137		static final class EntrySet<K,V> extends MapView<K,V>
3138		implements Set<Map.Entry<K,V>> {
3139		EntrySet(ConcurrentHashMapV8<K, V> map) { super(map); }
2273	–
3140		public final boolean contains(Object o) {
3141		Object k, v, r; Map.Entry<?,?> e;
3142		return ((o instanceof Map.Entry) &&
#	Line 2279 | Line 3145 | public class ConcurrentHashMapV8<K, V>
3145		(v = e.getValue()) != null &&
3146		(v == r || v.equals(r)));
3147		}
2282	–
3148		public final boolean remove(Object o) {
3149		Object k, v; Map.Entry<?,?> e;
3150		return ((o instanceof Map.Entry) &&
#	Line 2287 | Line 3152 | public class ConcurrentHashMapV8<K, V>
3152		(v = e.getValue()) != null &&
3153		map.remove(k, v));
3154		}
2290	–
3155		public final Iterator<Map.Entry<K,V>> iterator() {
3156		return new EntryIterator<K,V>(map);
3157		}
2294	–	final Iterator<?> iter() {
2295	–	return new SnapshotEntryIterator<K,V>(map);
2296	–	}
3158		public final boolean add(Entry<K,V> e) {
3159		throw new UnsupportedOperationException();
3160		}
#	Line 2339 | Line 3200 | public class ConcurrentHashMapV8<K, V>
3200		segments[i] = new Segment<K,V>(LOAD_FACTOR);
3201		}
3202		s.defaultWriteObject();
3203	<	InternalIterator it = new InternalIterator(table);
3204	<	while (it.next != null) {
3203	>	InternalIterator<K,V> it = new InternalIterator<K,V>(this);
3204	>	Object v;
3205	>	while ((v = it.advance()) != null) {
3206		s.writeObject(it.nextKey);
3207	<	s.writeObject(it.nextVal);
2346	<	it.advance();
3207	>	s.writeObject(v);
3208		}
3209		s.writeObject(null);
3210		s.writeObject(null);
#	Line 2369 | Line 3230 | public class ConcurrentHashMapV8<K, V>
3230		K k = (K) s.readObject();
3231		V v = (V) s.readObject();
3232		if (k != null && v != null) {
3233	<	p = new Node(spread(k.hashCode()), k, v, p);
3233	>	int h = spread(k.hashCode());
3234	>	p = new Node(h, k, v, p);
3235		++size;
3236		}
3237		else
#	Line 2385 | Line 3247 | public class ConcurrentHashMapV8<K, V>
3247		n = tableSizeFor(sz + (sz >>> 1) + 1);
3248		}
3249		int sc = sizeCtl;
3250	+	boolean collide = false;
3251		if (n > sc &&
3252		UNSAFE.compareAndSwapInt(this, sizeCtlOffset, sc, -1)) {
3253		try {
#	Line 2395 | Line 3258 | public class ConcurrentHashMapV8<K, V>
3258		while (p != null) {
3259		int j = p.hash & mask;
3260		Node next = p.next;
3261	<	p.next = tabAt(tab, j);
3261	>	Node q = p.next = tabAt(tab, j);
3262		setTabAt(tab, j, p);
3263	+	if (!collide && q != null && q.hash == p.hash)
3264	+	collide = true;
3265		p = next;
3266		}
3267		table = tab;
#	Line 2406 | Line 3271 | public class ConcurrentHashMapV8<K, V>
3271		} finally {
3272		sizeCtl = sc;
3273		}
3274	+	if (collide) { // rescan and convert to TreeBins
3275	+	Node[] tab = table;
3276	+	for (int i = 0; i < tab.length; ++i) {
3277	+	int c = 0;
3278	+	for (Node e = tabAt(tab, i); e != null; e = e.next) {
3279	+	if (++c > TREE_THRESHOLD &&
3280	+	(e.key instanceof Comparable)) {
3281	+	replaceWithTreeBin(tab, i, e.key);
3282	+	break;
3283	+	}
3284	+	}
3285	+	}
3286	+	}
3287		}
3288		if (!init) { // Can only happen if unsafely published.
3289		while (p != null) {

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