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Comparing jsr166/src/jsr166x/ConcurrentSkipListMap.java (file contents):
Revision 1.7 by jsr166, Sat Aug 1 22:12:59 2009 UTC vs.
Revision 1.20 by jsr166, Sat Dec 29 23:55:19 2012 UTC

#	Line 1 | Line 1
1		/*
2		* Written by Doug Lea with assistance from members of JCP JSR-166
3		* Expert Group and released to the public domain, as explained at
4	<	* http://creativecommons.org/licenses/publicdomain
4	>	* http://creativecommons.org/publicdomain/zero/1.0/
5		*/
6
7	<	package jsr166x;
7	>	package jsr166x;
8
9		import java.util.*;
10		import java.util.concurrent.*;
#	Line 56 | Line 56 | import java.util.concurrent.atomic.*;
56		*
57		* @author Doug Lea
58		* @param <K> the type of keys maintained by this map
59	<	* @param <V> the type of mapped values
59	>	* @param <V> the type of mapped values
60		*/
61	<	public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
61	>	public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
62		implements ConcurrentNavigableMap<K,V>,
63	<	Cloneable,
63	>	Cloneable,
64		java.io.Serializable {
65		/*
66		* This class implements a tree-like two-dimensionally linked skip
#	Line 74 | Line 74 | public class ConcurrentSkipListMap<K,V>
74		* possible list with 2 levels of index:
75		*
76		* Head nodes          Index nodes
77	<	* +-+    right        +-+                      +-+
77	>	* +-+    right        +-+                      +-+
78		* |2|---------------->| |--------------------->| |->null
79	<	* +-+                 +-+                      +-+
79	>	* +-+                 +-+                      +-+
80		*  | down              |                        |
81		*  v                   v                        v
82	<	* +-+            +-+  +-+       +-+            +-+       +-+
82	>	* +-+            +-+  +-+       +-+            +-+       +-+
83		* |1|----------->| |->| |------>| |----------->| |------>| |->null
84	<	* +-+            +-+  +-+       +-+            +-+       +-+
84	>	* +-+            +-+  +-+       +-+            +-+       +-+
85		*  v              |    |         |              |         |
86		* Nodes  next     v    v         v              v         v
87	<	* +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+
87	>	* +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+
88		* | |->|A|->|B|->|C|->|D|->|E|->|F|->|G|->|H|->|I|->|J|->|K|->null
89	<	* +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+
89	>	* +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+  +-+
90		*
91		* The base lists use a variant of the HM linked ordered set
92		* algorithm. See Tim Harris, "A pragmatic implementation of
#	Line 145 | Line 145 | public class ConcurrentSkipListMap<K,V>
145		* Here's the sequence of events for a deletion of node n with
146		* predecessor b and successor f, initially:
147		*
148	<	*        +------+       +------+      +------+
148	>	*        +------+       +------+      +------+
149		*   ...  |   b  |------>|   n  |----->|   f  | ...
150	<	*        +------+       +------+      +------+
150	>	*        +------+       +------+      +------+
151		*
152		* 1. CAS n's value field from non-null to null.
153		*    From this point on, no public operations encountering
#	Line 161 | Line 161 | public class ConcurrentSkipListMap<K,V>
161		*
162		*        +------+       +------+      +------+       +------+
163		*   ...  |   b  |------>|   n  |----->|marker|------>|   f  | ...
164	<	*        +------+       +------+      +------+       +------+
164	>	*        +------+       +------+      +------+       +------+
165		*
166		* 3. CAS b's next pointer over both n and its marker.
167		*    From this point on, no new traversals will encounter n,
168		*    and it can eventually be GCed.
169		*        +------+                                    +------+
170		*   ...  |   b  |----------------------------------->|   f  | ...
171	<	*        +------+                                    +------+
172	<	*
171	>	*        +------+                                    +------+
172	>	*
173		* A failure at step 1 leads to simple retry due to a lost race
174		* with another operation. Steps 2-3 can fail because some other
175		* thread noticed during a traversal a node with null value and
#	Line 188 | Line 188 | public class ConcurrentSkipListMap<K,V>
188		* nodes. This doesn't change the basic algorithm except for the
189		* need to make sure base traversals start at predecessors (here,
190		* b) that are not (structurally) deleted, otherwise retrying
191	<	* after processing the deletion.
191	>	* after processing the deletion.
192		*
193		* Index levels are maintained as lists with volatile next fields,
194		* using CAS to link and unlink.  Races are allowed in index-list
#	Line 292 | Line 292 | public class ConcurrentSkipListMap<K,V>
292
293		/**
294		* Special value used to identify base-level header
295	<	*/
295	>	*/
296		private static final Object BASE_HEADER = new Object();
297
298		/**
299	<	* The topmost head index of the skiplist.
299	>	* The topmost head index of the skiplist.
300		*/
301		private transient volatile HeadIndex<K,V> head;
302
#	Line 325 | Line 325 | public class ConcurrentSkipListMap<K,V>
325		private transient DescendingEntrySet descendingEntrySet;
326
327		/**
328	<	* Initialize or reset state. Needed by constructors, clone,
328	>	* Initializes or resets state. Needed by constructors, clone,
329		* clear, readObject. and ConcurrentSkipListSet.clone.
330		* (Note that comparator must be separately initialized.)
331		*/
332		final void initialize() {
333		keySet = null;
334	<	entrySet = null;
334	>	entrySet = null;
335		values = null;
336		descendingEntrySet = null;
337		descendingKeySet = null;
#	Line 341 | Line 341 | public class ConcurrentSkipListMap<K,V>
341		}
342
343		/** Updater for casHead */
344	<	private static final
345	<	AtomicReferenceFieldUpdater<ConcurrentSkipListMap, HeadIndex>
344	>	private static final
345	>	AtomicReferenceFieldUpdater<ConcurrentSkipListMap, HeadIndex>
346		headUpdater = AtomicReferenceFieldUpdater.newUpdater
347		(ConcurrentSkipListMap.class, HeadIndex.class, "head");
348
#	Line 390 | Line 390 | public class ConcurrentSkipListMap<K,V>
390		}
391
392		/** Updater for casNext */
393	<	static final AtomicReferenceFieldUpdater<Node, Node>
393	>	static final AtomicReferenceFieldUpdater<Node, Node>
394		nextUpdater = AtomicReferenceFieldUpdater.newUpdater
395		(Node.class, Node.class, "next");
396
397		/** Updater for casValue */
398	<	static final AtomicReferenceFieldUpdater<Node, Object>
398	>	static final AtomicReferenceFieldUpdater<Node, Object>
399		valueUpdater = AtomicReferenceFieldUpdater.newUpdater
400		(Node.class, Object.class, "value");
401
#	Line 414 | Line 414 | public class ConcurrentSkipListMap<K,V>
414		}
415
416		/**
417	<	* Return true if this node is a marker. This method isn't
417	>	* Returns true if this node is a marker. This method isn't
418		* actually called in an any current code checking for markers
419		* because callers will have already read value field and need
420		* to use that read (not another done here) and so directly
#	Line 427 | Line 427 | public class ConcurrentSkipListMap<K,V>
427		}
428
429		/**
430	<	* Return true if this node is the header of base-level list.
430	>	* Returns true if this node is the header of base-level list.
431		* @return true if this node is header node
432		*/
433		boolean isBaseHeader() {
#	Line 465 | Line 465 | public class ConcurrentSkipListMap<K,V>
465		}
466
467		/**
468	<	* Return value if this node contains a valid key-value pair,
469	<	* else null.
468	>	* Returns value if this node contains a valid key-value pair,
469	>	* else null.
470		* @return this node's value if it isn't a marker or header or
471		* is deleted, else null.
472		*/
#	Line 478 | Line 478 | public class ConcurrentSkipListMap<K,V>
478		}
479
480		/**
481	<	* Create and return a new SnapshotEntry holding current
482	<	* mapping if this node holds a valid value, else null
481	>	* Creates and returns a new SnapshotEntry holding current
482	>	* mapping if this node holds a valid value, else null.
483		* @return new entry or null
484		*/
485		SnapshotEntry<K,V> createSnapshot() {
#	Line 508 | Line 508 | public class ConcurrentSkipListMap<K,V>
508
509		/**
510		* Creates index node with given values
511	<	*/
511	>	*/
512		Index(Node<K,V> node, Index<K,V> down, Index<K,V> right) {
513		this.node = node;
514		this.key = node.key;
#	Line 517 | Line 517 | public class ConcurrentSkipListMap<K,V>
517		}
518
519		/** Updater for casRight */
520	<	static final AtomicReferenceFieldUpdater<Index, Index>
520	>	static final AtomicReferenceFieldUpdater<Index, Index>
521		rightUpdater = AtomicReferenceFieldUpdater.newUpdater
522		(Index.class, Index.class, "right");
523
#	Line 546 | Line 546 | public class ConcurrentSkipListMap<K,V>
546		*/
547		final boolean link(Index<K,V> succ, Index<K,V> newSucc) {
548		Node<K,V> n = node;
549	<	newSucc.right = succ;
549	>	newSucc.right = succ;
550		return n.value != null && casRight(succ, newSucc);
551		}
552
#	Line 573 | Line 573 | public class ConcurrentSkipListMap<K,V>
573		super(node, down, right);
574		this.level = level;
575		}
576	<	}
576	>	}
577
578		/* ---------------- Map.Entry support -------------- */
579
#	Line 581 | Line 581 | public class ConcurrentSkipListMap<K,V>
581		* An immutable representation of a key-value mapping as it
582		* existed at some point in time. This class does <em>not</em>
583		* support the <tt>Map.Entry.setValue</tt> method.
584	<	*/
584	>	*/
585		static class SnapshotEntry<K,V> implements Map.Entry<K,V> {
586	<	private final K key;
587	<	private final V value;
586	>	private final K key;
587	>	private final V value;
588
589		/**
590		* Creates a new entry representing the given key and value.
#	Line 592 | Line 592 | public class ConcurrentSkipListMap<K,V>
592		* @param value the value
593		*/
594		SnapshotEntry(K key, V value) {
595	<	this.key = key;
596	<	this.value = value;
597	<	}
598	<
599	<	/**
600	<	* Returns the key corresponding to this entry.
601	<	*
602	<	* @return the key corresponding to this entry.
603	<	*/
595	>	this.key = key;
596	>	this.value = value;
597	>	}
598	>
599	>	/**
600	>	* Returns the key corresponding to this entry.
601	>	*
602	>	* @return the key corresponding to this entry
603	>	*/
604		public K getKey() {
605		return key;
606		}
607
608	<	/**
609	<	* Returns the value corresponding to this entry.
610	<	*
611	<	* @return the value corresponding to this entry.
612	<	*/
608	>	/**
609	>	* Returns the value corresponding to this entry.
610	>	*
611	>	* @return the value corresponding to this entry
612	>	*/
613		public V getValue() {
614	<	return value;
614	>	return value;
615		}
616
617	<	/**
618	<	* Always fails, throwing <tt>UnsupportedOperationException</tt>.
619	<	* @throws UnsupportedOperationException always.
617	>	/**
618	>	* Always fails, throwing <tt>UnsupportedOperationException</tt>.
619	>	* @throws UnsupportedOperationException always
620		*/
621		public V setValue(V value) {
622		throw new UnsupportedOperationException();
#	Line 646 | Line 646 | public class ConcurrentSkipListMap<K,V>
646		* Returns a String consisting of the key followed by an
647		* equals sign (<tt>"="</tt>) followed by the associated
648		* value.
649	<	* @return a String representation of this entry.
649	>	* @return a String representation of this entry
650		*/
651		public String toString() {
652	<	return getKey() + "=" + getValue();
652	>	return getKey() + "=" + getValue();
653		}
654		}
655
#	Line 688 | Line 688 | public class ConcurrentSkipListMap<K,V>
688		* which is propagated back to caller.
689		*/
690		private Comparable<K> comparable(Object key) throws ClassCastException {
691	<	if (key == null)
691	>	if (key == null)
692		throw new NullPointerException();
693	<	return (comparator != null)
694	<	? new ComparableUsingComparator(key, comparator)
693	>	return (comparator != null)
694	>	? new ComparableUsingComparator(key, comparator)
695		: (Comparable<K>)key;
696		}
697
698		/**
699	<	* Compare using comparator or natural ordering. Used when the
699	>	* Compares using comparator or natural ordering. Used when the
700		* ComparableUsingComparator approach doesn't apply.
701		*/
702		int compare(K k1, K k2) throws ClassCastException {
#	Line 708 | Line 708 | public class ConcurrentSkipListMap<K,V>
708		}
709
710		/**
711	<	* Return true if given key greater than or equal to least and
711	>	* Returns true if given key greater than or equal to least and
712		* strictly less than fence, bypassing either test if least or
713	<	* fence oare null. Needed mainly in submap operations.
713	>	* fence are null. Needed mainly in submap operations.
714		*/
715		boolean inHalfOpenRange(K key, K least, K fence) {
716	<	if (key == null)
716	>	if (key == null)
717		throw new NullPointerException();
718		return ((least == null || compare(key, least) >= 0) &&
719		(fence == null || compare(key, fence) <  0));
720		}
721
722		/**
723	<	* Return true if given key greater than or equal to least and less
723	>	* Returns true if given key greater than or equal to least and less
724		* or equal to fence. Needed mainly in submap operations.
725		*/
726		boolean inOpenRange(K key, K least, K fence) {
727	<	if (key == null)
727	>	if (key == null)
728		throw new NullPointerException();
729		return ((least == null || compare(key, least) >= 0) &&
730		(fence == null || compare(key, fence) <= 0));
#	Line 733 | Line 733 | public class ConcurrentSkipListMap<K,V>
733		/* ---------------- Traversal -------------- */
734
735		/**
736	<	* Return a base-level node with key strictly less than given key,
736	>	* Returns a base-level node with key strictly less than given key,
737		* or the base-level header if there is no such node.  Also
738		* unlinks indexes to deleted nodes found along the way.  Callers
739		* rely on this side-effect of clearing indices to deleted nodes.
740		* @param key the key
741	<	* @return a predecessor of key
741	>	* @return a predecessor of key
742		*/
743		private Node<K,V> findPredecessor(Comparable<K> key) {
744		for (;;) {
#	Line 757 | Line 757 | public class ConcurrentSkipListMap<K,V>
757		continue;
758		}
759		}
760	<	if ((d = q.down) != null)
760	>	if ((d = q.down) != null)
761		q = d;
762		else
763		return q.node;
#	Line 766 | Line 766 | public class ConcurrentSkipListMap<K,V>
766		}
767
768		/**
769	<	* Return node holding key or null if no such, clearing out any
769	>	* Returns node holding key or null if no such, clearing out any
770		* deleted nodes seen along the way.  Repeatedly traverses at
771		* base-level looking for key starting at predecessor returned
772		* from findPredecessor, processing base-level deletions as
#	Line 787 | Line 787 | public class ConcurrentSkipListMap<K,V>
787		*       here because doing so would not usually outweigh cost of
788		*       restarting.
789		*
790	<	*   (3) n is a marker or n's predecessor's value field is null,
790	>	*   (3) n is a marker or n's predecessor's value field is null,
791		*       indicating (among other possibilities) that
792		*       findPredecessor returned a deleted node. We can't unlink
793		*       the node because we don't know its predecessor, so rely
#	Line 805 | Line 805 | public class ConcurrentSkipListMap<K,V>
805		* findLast. They can't easily share code because each uses the
806		* reads of fields held in locals occurring in the orders they
807		* were performed.
808	<	*
808	>	*
809		* @param key the key
810	<	* @return node holding key, or null if no such.
810	>	* @return node holding key, or null if no such
811		*/
812		private Node<K,V> findNode(Comparable<K> key) {
813		for (;;) {
814		Node<K,V> b = findPredecessor(key);
815		Node<K,V> n = b.next;
816		for (;;) {
817	<	if (n == null)
817	>	if (n == null)
818		return null;
819		Node<K,V> f = n.next;
820		if (n != b.next)                // inconsistent read
#	Line 829 | Line 829 | public class ConcurrentSkipListMap<K,V>
829		int c = key.compareTo(n.key);
830		if (c < 0)
831		return null;
832	<	if (c == 0)
832	>	if (c == 0)
833		return n;
834		b = n;
835		n = f;
#	Line 837 | Line 837 | public class ConcurrentSkipListMap<K,V>
837		}
838		}
839
840	<	/**
840	>	/**
841		* Specialized variant of findNode to perform Map.get. Does a weak
842		* traversal, not bothering to fix any deleted index nodes,
843		* returning early if it happens to see key in index, and passing
#	Line 856 | Line 856 | public class ConcurrentSkipListMap<K,V>
856		for (;;) {
857		K rk;
858		Index<K,V> d, r;
859	<	if ((r = q.right) != null &&
859	>	if ((r = q.right) != null &&
860		(rk = r.key) != null && rk != bound) {
861		int c = key.compareTo(rk);
862		if (c > 0) {
#	Line 865 | Line 865 | public class ConcurrentSkipListMap<K,V>
865		}
866		if (c == 0) {
867		Object v = r.node.value;
868	<	return (v != null)? (V)v : getUsingFindNode(key);
868	>	return (v != null) ? (V)v : getUsingFindNode(key);
869		}
870		bound = rk;
871		}
872	<	if ((d = q.down) != null)
872	>	if ((d = q.down) != null)
873		q = d;
874		else {
875		for (Node<K,V> n = q.node.next; n != null; n = n.next) {
#	Line 878 | Line 878 | public class ConcurrentSkipListMap<K,V>
878		int c = key.compareTo(nk);
879		if (c == 0) {
880		Object v = n.value;
881	<	return (v != null)? (V)v : getUsingFindNode(key);
881	>	return (v != null) ? (V)v : getUsingFindNode(key);
882		}
883		if (c < 0)
884		return null;
#	Line 890 | Line 890 | public class ConcurrentSkipListMap<K,V>
890		}
891
892		/**
893	<	* Perform map.get via findNode.  Used as a backup if doGet
893	>	* Performs map.get via findNode.  Used as a backup if doGet
894		* encounters an in-progress deletion.
895		* @param key the key
896		* @return the value, or null if absent
#	Line 916 | Line 916 | public class ConcurrentSkipListMap<K,V>
916		/**
917		* Main insertion method.  Adds element if not present, or
918		* replaces value if present and onlyIfAbsent is false.
919	<	* @param kkey the key
919	>	* @param kkey the key
920		* @param value  the value that must be associated with key
921		* @param onlyIfAbsent if should not insert if already present
922		* @return the old value, or null if newly inserted
#	Line 952 | Line 952 | public class ConcurrentSkipListMap<K,V>
952		}
953		// else c < 0; fall through
954		}
955	<
955	>
956		Node<K,V> z = new Node<K,V>(kkey, value, n);
957	<	if (!b.casNext(n, z))
957	>	if (!b.casNext(n, z))
958		break;         // restart if lost race to append to b
959	<	int level = randomLevel();
960	<	if (level > 0)
959	>	int level = randomLevel();
960	>	if (level > 0)
961		insertIndex(z, level);
962		return null;
963		}
#	Line 965 | Line 965 | public class ConcurrentSkipListMap<K,V>
965		}
966
967		/**
968	<	* Return a random level for inserting a new node.
968	>	* Returns a random level for inserting a new node.
969		* Hardwired to k=1, p=0.5, max 31.
970		*
971		* This uses a cheap pseudo-random function that according to
#	Line 979 | Line 979 | public class ConcurrentSkipListMap<K,V>
979		int level = 0;
980		int r = randomSeed;
981		randomSeed = r * 134775813 + 1;
982	<	if (r < 0) {
983	<	while ((r <<= 1) > 0)
982	>	if (r < 0) {
983	>	while ((r <<= 1) > 0)
984		++level;
985		}
986		return level;
987		}
988
989		/**
990	<	* Create and add index nodes for given node.
990	>	* Creates and adds index nodes for given node.
991		* @param z the node
992		* @param level the level of the index
993		*/
#	Line 1013 | Line 1013 | public class ConcurrentSkipListMap<K,V>
1013		level = max + 1;
1014		Index<K,V>[] idxs = (Index<K,V>[])new Index[level+1];
1015		Index<K,V> idx = null;
1016	<	for (int i = 1; i <= level; ++i)
1016	>	for (int i = 1; i <= level; ++i)
1017		idxs[i] = idx = new Index<K,V>(z, idx, null);
1018
1019		HeadIndex<K,V> oldh;
#	Line 1027 | Line 1027 | public class ConcurrentSkipListMap<K,V>
1027		}
1028		HeadIndex<K,V> newh = oldh;
1029		Node<K,V> oldbase = oldh.node;
1030	<	for (int j = oldLevel+1; j <= level; ++j)
1030	>	for (int j = oldLevel+1; j <= level; ++j)
1031		newh = new HeadIndex<K,V>(oldbase, newh, idxs[j], j);
1032		if (casHead(oldh, newh)) {
1033		k = oldLevel;
#	Line 1039 | Line 1039 | public class ConcurrentSkipListMap<K,V>
1039		}
1040
1041		/**
1042	<	* Add given index nodes from given level down to 1.
1042	>	* Adds given index nodes from given level down to 1.
1043		* @param idx the topmost index node being inserted
1044		* @param h the value of head to use to insert. This must be
1045		* snapshotted by callers to provide correct insertion level
#	Line 1065 | Line 1065 | public class ConcurrentSkipListMap<K,V>
1065		if (q.unlink(r))
1066		continue;
1067		else
1068	<	break;
1068	>	break;
1069		}
1070		if (c > 0) {
1071		q = r;
#	Line 1079 | Line 1079 | public class ConcurrentSkipListMap<K,V>
1079		findNode(key); // cleans up
1080		return;
1081		}
1082	<	if (!q.link(r, t))
1082	>	if (!q.link(r, t))
1083		break; // restart
1084		if (--insertionLevel == 0) {
1085		// need final deletion check before return
1086	<	if (t.indexesDeletedNode())
1087	<	findNode(key);
1086	>	if (t.indexesDeletedNode())
1087	>	findNode(key);
1088		return;
1089		}
1090		}
1091
1092	<	if (j > insertionLevel && j <= indexLevel)
1092	>	if (j > insertionLevel && j <= indexLevel)
1093		t = t.down;
1094		q = q.down;
1095		--j;
#	Line 1111 | Line 1111 | public class ConcurrentSkipListMap<K,V>
1111		* index nodes because it might be the case that some or all
1112		* indexes hadn't been inserted yet for this node during initial
1113		* search for it, and we'd like to ensure lack of garbage
1114	<	* retention, so must call to be sure.
1114	>	* retention, so must call to be sure.
1115		*
1116		* @param okey the key
1117		* @param value if non-null, the value that must be
#	Line 1120 | Line 1120 | public class ConcurrentSkipListMap<K,V>
1120		*/
1121		private V doRemove(Object okey, Object value) {
1122		Comparable<K> key = comparable(okey);
1123	<	for (;;) {
1123	>	for (;;) {
1124		Node<K,V> b = findPredecessor(key);
1125		Node<K,V> n = b.next;
1126		for (;;) {
1127	<	if (n == null)
1127	>	if (n == null)
1128		return null;
1129		Node<K,V> f = n.next;
1130		if (n != b.next)                    // inconsistent read
#	Line 1144 | Line 1144 | public class ConcurrentSkipListMap<K,V>
1144		n = f;
1145		continue;
1146		}
1147	<	if (value != null && !value.equals(v))
1148	<	return null;
1149	<	if (!n.casValue(v, null))
1147	>	if (value != null && !value.equals(v))
1148	>	return null;
1149	>	if (!n.casValue(v, null))
1150		break;
1151	<	if (!n.appendMarker(f) || !b.casNext(n, f))
1151	>	if (!n.appendMarker(f) || !b.casNext(n, f))
1152		findNode(key);                  // Retry via findNode
1153		else {
1154		findPredecessor(key);           // Clean index
1155	<	if (head.right == null)
1155	>	if (head.right == null)
1156		tryReduceLevel();
1157		}
1158		return (V)v;
#	Line 1185 | Line 1185 | public class ConcurrentSkipListMap<K,V>
1185		HeadIndex<K,V> d;
1186		HeadIndex<K,V> e;
1187		if (h.level > 3 &&
1188	<	(d = (HeadIndex<K,V>)h.down) != null &&
1189	<	(e = (HeadIndex<K,V>)d.down) != null &&
1190	<	e.right == null &&
1191	<	d.right == null &&
1188	>	(d = (HeadIndex<K,V>)h.down) != null &&
1189	>	(e = (HeadIndex<K,V>)d.down) != null &&
1190	>	e.right == null &&
1191	>	d.right == null &&
1192		h.right == null &&
1193		casHead(h, d) && // try to set
1194		h.right != null) // recheck
#	Line 1214 | Line 1214 | public class ConcurrentSkipListMap<K,V>
1214		Node<K,V> n = b.next;
1215		if (n == null)
1216		return null;
1217	<	if (n.value != null)
1217	>	if (n.value != null)
1218		return n;
1219		n.helpDelete(b, n.next);
1220		}
1221		}
1222
1223		/**
1224	<	* Remove first entry; return either its key or a snapshot.
1224	>	* Removes first entry; return either its key or a snapshot.
1225		* @param keyOnly if true return key, else return SnapshotEntry
1226		* (This is a little ugly, but avoids code duplication.)
1227		* @return null if empty, first key if keyOnly true, else key,value entry
1228		*/
1229		Object doRemoveFirst(boolean keyOnly) {
1230	<	for (;;) {
1230	>	for (;;) {
1231		Node<K,V> b = head.node;
1232		Node<K,V> n = b.next;
1233	<	if (n == null)
1233	>	if (n == null)
1234		return null;
1235		Node<K,V> f = n.next;
1236		if (n != b.next)
#	Line 1246 | Line 1246 | public class ConcurrentSkipListMap<K,V>
1246		findFirst(); // retry
1247		clearIndexToFirst();
1248		K key = n.key;
1249	<	return (keyOnly)? key : new SnapshotEntry<K,V>(key, (V)v);
1249	>	return keyOnly ? key : new SnapshotEntry<K,V>(key, (V)v);
1250		}
1251		}
1252
1253		/**
1254	<	* Clear out index nodes associated with deleted first entry.
1255	<	* Needed by doRemoveFirst
1254	>	* Clears out index nodes associated with deleted first entry.
1255	>	* Needed by doRemoveFirst.
1256		*/
1257		private void clearIndexToFirst() {
1258		for (;;) {
#	Line 1260 | Line 1260 | public class ConcurrentSkipListMap<K,V>
1260		for (;;) {
1261		Index<K,V> r = q.right;
1262		if (r != null && r.indexesDeletedNode() && !q.unlink(r))
1263	<	break;
1263	>	break;
1264		if ((q = q.down) == null) {
1265	<	if (head.right == null)
1265	>	if (head.right == null)
1266		tryReduceLevel();
1267		return;
1268		}
#	Line 1271 | Line 1271 | public class ConcurrentSkipListMap<K,V>
1271		}
1272
1273		/**
1274	<	* Remove first entry; return key or null if empty.
1274	>	* Removes first entry; return key or null if empty.
1275		*/
1276		K pollFirstKey() {
1277		return (K)doRemoveFirst(true);
#	Line 1296 | Line 1296 | public class ConcurrentSkipListMap<K,V>
1296		if (r.indexesDeletedNode()) {
1297		q.unlink(r);
1298		q = head; // restart
1299	<	}
1299	>	}
1300		else
1301		q = r;
1302		} else if ((d = q.down) != null) {
#	Line 1305 | Line 1305 | public class ConcurrentSkipListMap<K,V>
1305		Node<K,V> b = q.node;
1306		Node<K,V> n = b.next;
1307		for (;;) {
1308	<	if (n == null)
1309	<	return (b.isBaseHeader())? null : b;
1308	>	if (n == null)
1309	>	return b.isBaseHeader() ? null : b;
1310		Node<K,V> f = n.next;            // inconsistent read
1311		if (n != b.next)
1312		break;
#	Line 1332 | Line 1332 | public class ConcurrentSkipListMap<K,V>
1332		* @return null if empty, last key if keyOnly true, else key,value entry
1333		*/
1334		Object doRemoveLast(boolean keyOnly) {
1335	<	for (;;) {
1335	>	for (;;) {
1336		Node<K,V> b = findPredecessorOfLast();
1337		Node<K,V> n = b.next;
1338		if (n == null) {
1339		if (b.isBaseHeader())               // empty
1340		return null;
1341	<	else
1341	>	else
1342		continue; // all b's successors are deleted; retry
1343		}
1344		for (;;) {
#	Line 1357 | Line 1357 | public class ConcurrentSkipListMap<K,V>
1357		n = f;
1358		continue;
1359		}
1360	<	if (!n.casValue(v, null))
1360	>	if (!n.casValue(v, null))
1361		break;
1362		K key = n.key;
1363		Comparable<K> ck = comparable(key);
1364	<	if (!n.appendMarker(f) || !b.casNext(n, f))
1364	>	if (!n.appendMarker(f) || !b.casNext(n, f))
1365		findNode(ck);                  // Retry via findNode
1366		else {
1367		findPredecessor(ck);           // Clean index
1368	<	if (head.right == null)
1368	>	if (head.right == null)
1369		tryReduceLevel();
1370		}
1371	<	return (keyOnly)? key : new SnapshotEntry<K,V>(key, (V)v);
1371	>	return keyOnly ? key : new SnapshotEntry<K,V>(key, (V)v);
1372		}
1373		}
1374		}
#	Line 1378 | Line 1378 | public class ConcurrentSkipListMap<K,V>
1378		* last valid node. Needed by doRemoveLast. It is possible that
1379		* all successors of returned node will have been deleted upon
1380		* return, in which case this method can be retried.
1381	<	* @return likely predecessor of last node.
1381	>	* @return likely predecessor of last node
1382		*/
1383		private Node<K,V> findPredecessorOfLast() {
1384		for (;;) {
#	Line 1396 | Line 1396 | public class ConcurrentSkipListMap<K,V>
1396		continue;
1397		}
1398		}
1399	<	if ((d = q.down) != null)
1399	>	if ((d = q.down) != null)
1400		q = d;
1401	<	else
1401	>	else
1402		return q.node;
1403		}
1404		}
1405		}
1406
1407		/**
1408	<	* Remove last entry; return key or null if empty.
1408	>	* Removes last entry; return key or null if empty.
1409		*/
1410		K pollLastKey() {
1411		return (K)doRemoveLast(true);
#	Line 1431 | Line 1431 | public class ConcurrentSkipListMap<K,V>
1431		Node<K,V> b = findPredecessor(key);
1432		Node<K,V> n = b.next;
1433		for (;;) {
1434	<	if (n == null)
1435	<	return ((rel & LT) == 0 || b.isBaseHeader())? null : b;
1434	>	if (n == null)
1435	>	return ((rel & LT) == 0 || b.isBaseHeader()) ? null : b;
1436		Node<K,V> f = n.next;
1437		if (n != b.next)                  // inconsistent read
1438		break;
#	Line 1448 | Line 1448 | public class ConcurrentSkipListMap<K,V>
1448		(c <  0 && (rel & LT) == 0))
1449		return n;
1450		if ( c <= 0 && (rel & LT) != 0)
1451	<	return (b.isBaseHeader())? null : b;
1451	>	return b.isBaseHeader() ? null : b;
1452		b = n;
1453		n = f;
1454		}
#	Line 1456 | Line 1456 | public class ConcurrentSkipListMap<K,V>
1456		}
1457
1458		/**
1459	<	* Return SnapshotEntry for results of findNear.
1459	>	* Returns SnapshotEntry for results of findNear.
1460		* @param kkey the key
1461		* @param rel the relation -- OR'ed combination of EQ, LT, GT
1462		* @return Entry fitting relation, or null if no such
#	Line 1473 | Line 1473 | public class ConcurrentSkipListMap<K,V>
1473		}
1474
1475		/**
1476	<	* Return ceiling, or first node if key is <tt>null</tt>
1476	>	* Returns ceiling, or first node if key is <tt>null</tt>.
1477		*/
1478		Node<K,V> findCeiling(K key) {
1479	<	return (key == null)? findFirst() : findNear(key, GT|EQ);
1479	>	return (key == null) ? findFirst() : findNear(key, GT|EQ);
1480		}
1481
1482		/**
1483	<	* Return lower node, or last node if key is <tt>null</tt>
1483	>	* Returns lower node, or last node if key is <tt>null</tt>.
1484		*/
1485		Node<K,V> findLower(K key) {
1486	<	return (key == null)? findLast() : findNear(key, LT);
1486	>	return (key == null) ? findLast() : findNear(key, LT);
1487		}
1488
1489		/**
1490	<	* Return SnapshotEntry or key for results of findNear ofter screening
1490	>	* Returns SnapshotEntry or key for results of findNear ofter screening
1491		* to ensure result is in given range. Needed by submaps.
1492		* @param kkey the key
1493		* @param rel the relation -- OR'ed combination of EQ, LT, GT
#	Line 1512 | Line 1512 | public class ConcurrentSkipListMap<K,V>
1512		return null;
1513		K k = n.key;
1514		V v = n.getValidValue();
1515	<	if (v != null)
1516	<	return keyOnly? k : new SnapshotEntry<K,V>(k, v);
1515	>	if (v != null)
1516	>	return keyOnly ? k : new SnapshotEntry<K,V>(k, v);
1517		}
1518		}
1519
1520		/**
1521	<	* Find and remove least element of subrange.
1521	>	* Finds and removes least element of subrange.
1522		* @param least minimum allowed key value
1523		* @param fence key greater than maximum allowed key value
1524		* @param keyOnly if true return key, else return SnapshotEntry
#	Line 1534 | Line 1534 | public class ConcurrentSkipListMap<K,V>
1534		return null;
1535		V v = doRemove(k, null);
1536		if (v != null)
1537	<	return (keyOnly)? k : new SnapshotEntry<K,V>(k, v);
1537	>	return keyOnly ? k : new SnapshotEntry<K,V>(k, v);
1538		}
1539		}
1540
1541		/**
1542	<	* Find and remove greatest element of subrange.
1542	>	* Finds and removes greatest element of subrange.
1543		* @param least minimum allowed key value
1544		* @param fence key greater than maximum allowed key value
1545		* @param keyOnly if true return key, else return SnapshotEntry
#	Line 1555 | Line 1555 | public class ConcurrentSkipListMap<K,V>
1555		return null;
1556		V v = doRemove(k, null);
1557		if (v != null)
1558	<	return (keyOnly)? k : new SnapshotEntry<K,V>(k, v);
1558	>	return keyOnly ? k : new SnapshotEntry<K,V>(k, v);
1559		}
1560		}
1561
#	Line 1563 | Line 1563 | public class ConcurrentSkipListMap<K,V>
1563
1564		/**
1565		* Constructs a new empty map, sorted according to the keys' natural
1566	<	* order.
1566	>	* order.
1567		*/
1568		public ConcurrentSkipListMap() {
1569		this.comparator = null;
#	Line 1584 | Line 1584 | public class ConcurrentSkipListMap<K,V>
1584
1585		/**
1586		* Constructs a new map containing the same mappings as the given map,
1587	<	* sorted according to the keys' <i>natural order</i>.
1587	>	* sorted according to the keys' <i>natural order</i>.
1588		*
1589	<	* @param  m the map whose mappings are to be placed in this map.
1589	>	* @param  m the map whose mappings are to be placed in this map
1590		* @throws ClassCastException if the keys in m are not Comparable, or
1591	<	*         are not mutually comparable.
1592	<	* @throws NullPointerException if the specified map is <tt>null</tt>.
1591	>	*         are not mutually comparable
1592	>	* @throws NullPointerException if the specified map is <tt>null</tt>
1593		*/
1594		public ConcurrentSkipListMap(Map<? extends K, ? extends V> m) {
1595		this.comparator = null;
#	Line 1599 | Line 1599 | public class ConcurrentSkipListMap<K,V>
1599
1600		/**
1601		* Constructs a new map containing the same mappings as the given
1602	<	* <tt>SortedMap</tt>, sorted according to the same ordering.
1602	>	* <tt>SortedMap</tt>, sorted according to the same ordering.
1603		* @param m the sorted map whose mappings are to be placed in this
1604		* map, and whose comparator is to be used to sort this map.
1605		* @throws NullPointerException if the specified sorted map is
#	Line 1615 | Line 1615 | public class ConcurrentSkipListMap<K,V>
1615		* Returns a shallow copy of this <tt>Map</tt> instance. (The keys and
1616		* values themselves are not cloned.)
1617		*
1618	<	* @return a shallow copy of this Map.
1618	>	* @return a shallow copy of this Map
1619		*/
1620		public Object clone() {
1621		ConcurrentSkipListMap<K,V> clone = null;
#	Line 1647 | Line 1647 | public class ConcurrentSkipListMap<K,V>
1647		ArrayList<Index<K,V>> preds = new ArrayList<Index<K,V>>();
1648
1649		// initialize
1650	<	for (int i = 0; i <= h.level; ++i)
1650	>	for (int i = 0; i <= h.level; ++i)
1651		preds.add(null);
1652		Index<K,V> q = h;
1653		for (int i = h.level; i > 0; --i) {
#	Line 1655 | Line 1655 | public class ConcurrentSkipListMap<K,V>
1655		q = q.down;
1656		}
1657
1658	<	Iterator<? extends Map.Entry<? extends K, ? extends V>> it =
1658	>	Iterator<? extends Map.Entry<? extends K, ? extends V>> it =
1659		map.entrySet().iterator();
1660		while (it.hasNext()) {
1661		Map.Entry<? extends K, ? extends V> e = it.next();
#	Line 1672 | Line 1672 | public class ConcurrentSkipListMap<K,V>
1672		Index<K,V> idx = null;
1673		for (int i = 1; i <= j; ++i) {
1674		idx = new Index<K,V>(z, idx, null);
1675	<	if (i > h.level)
1675	>	if (i > h.level)
1676		h = new HeadIndex<K,V>(h.node, h, idx, i);
1677
1678		if (i < preds.size()) {
#	Line 1689 | Line 1689 | public class ConcurrentSkipListMap<K,V>
1689		/* ---------------- Serialization -------------- */
1690
1691		/**
1692	<	* Save the state of the <tt>Map</tt> instance to a stream.
1692	>	* Saves the state of the <tt>Map</tt> instance to a stream.
1693		*
1694		* @serialData The key (Object) and value (Object) for each
1695	<	* key-value mapping represented by the Map, followed by
1695	>	* key-value mapping represented by the Map, followed by
1696		* <tt>null</tt>. The key-value mappings are emitted in key-order
1697		* (as determined by the Comparator, or by the keys' natural
1698		* ordering if no Comparator).
#	Line 1714 | Line 1714 | public class ConcurrentSkipListMap<K,V>
1714		}
1715
1716		/**
1717	<	* Reconstitute the <tt>Map</tt> instance from a stream.
1717	>	* Reconstitutes the <tt>Map</tt> instance from a stream.
1718		*/
1719		private void readObject(final java.io.ObjectInputStream s)
1720		throws java.io.IOException, ClassNotFoundException {
#	Line 1723 | Line 1723 | public class ConcurrentSkipListMap<K,V>
1723		// Reset transients
1724		initialize();
1725
1726	<	/*
1726	>	/*
1727		* This is nearly identical to buildFromSorted, but is
1728		* distinct because readObject calls can't be nicely adapted
1729		* as the kind of iterator needed by buildFromSorted. (They
#	Line 1734 | Line 1734 | public class ConcurrentSkipListMap<K,V>
1734		HeadIndex<K,V> h = head;
1735		Node<K,V> basepred = h.node;
1736		ArrayList<Index<K,V>> preds = new ArrayList<Index<K,V>>();
1737	<	for (int i = 0; i <= h.level; ++i)
1737	>	for (int i = 0; i <= h.level; ++i)
1738		preds.add(null);
1739		Index<K,V> q = h;
1740		for (int i = h.level; i > 0; --i) {
#	Line 1747 | Line 1747 | public class ConcurrentSkipListMap<K,V>
1747		if (k == null)
1748		break;
1749		Object v = s.readObject();
1750	<	if (v == null)
1750	>	if (v == null)
1751		throw new NullPointerException();
1752		K key = (K) k;
1753		V val = (V) v;
#	Line 1760 | Line 1760 | public class ConcurrentSkipListMap<K,V>
1760		Index<K,V> idx = null;
1761		for (int i = 1; i <= j; ++i) {
1762		idx = new Index<K,V>(z, idx, null);
1763	<	if (i > h.level)
1763	>	if (i > h.level)
1764		h = new HeadIndex<K,V>(h.node, h, idx, i);
1765
1766		if (i < preds.size()) {
#	Line 1779 | Line 1779 | public class ConcurrentSkipListMap<K,V>
1779		/**
1780		* Returns <tt>true</tt> if this map contains a mapping for the specified
1781		* key.
1782	<	* @param key key whose presence in this map is to be tested.
1782	>	* @param key key whose presence in this map is to be tested
1783		* @return <tt>true</tt> if this map contains a mapping for the
1784	<	*            specified key.
1784	>	*            specified key
1785		* @throws ClassCastException if the key cannot be compared with the keys
1786	<	*                  currently in the map.
1787	<	* @throws NullPointerException if the key is <tt>null</tt>.
1786	>	*                  currently in the map
1787	>	* @throws NullPointerException if the key is <tt>null</tt>
1788		*/
1789		public boolean containsKey(Object key) {
1790		return doGet(key) != null;
#	Line 1792 | Line 1792 | public class ConcurrentSkipListMap<K,V>
1792
1793		/**
1794		* Returns the value to which this map maps the specified key.  Returns
1795	<	* <tt>null</tt> if the map contains no mapping for this key.
1795	>	* <tt>null</tt> if the map contains no mapping for this key.
1796		*
1797	<	* @param key key whose associated value is to be returned.
1797	>	* @param key key whose associated value is to be returned
1798		* @return the value to which this map maps the specified key, or
1799	<	*               <tt>null</tt> if the map contains no mapping for the key.
1799	>	*               <tt>null</tt> if the map contains no mapping for the key
1800		* @throws ClassCastException if the key cannot be compared with the keys
1801	<	*                  currently in the map.
1802	<	* @throws NullPointerException if the key is <tt>null</tt>.
1801	>	*                  currently in the map
1802	>	* @throws NullPointerException if the key is <tt>null</tt>
1803		*/
1804		public V get(Object key) {
1805		return doGet(key);
#	Line 1810 | Line 1810 | public class ConcurrentSkipListMap<K,V>
1810		* If the map previously contained a mapping for this key, the old
1811		* value is replaced.
1812		*
1813	<	* @param key key with which the specified value is to be associated.
1814	<	* @param value value to be associated with the specified key.
1813	>	* @param key key with which the specified value is to be associated
1814	>	* @param value value to be associated with the specified key
1815		*
1816		* @return previous value associated with specified key, or <tt>null</tt>
1817	<	*         if there was no mapping for key.
1817	>	*         if there was no mapping for key
1818		* @throws ClassCastException if the key cannot be compared with the keys
1819	<	*            currently in the map.
1820	<	* @throws NullPointerException if the key or value are <tt>null</tt>.
1819	>	*            currently in the map
1820	>	* @throws NullPointerException if the key or value are <tt>null</tt>
1821		*/
1822		public V put(K key, V value) {
1823	<	if (value == null)
1823	>	if (value == null)
1824		throw new NullPointerException();
1825		return doPut(key, value, false);
1826		}
#	Line 1830 | Line 1830 | public class ConcurrentSkipListMap<K,V>
1830		*
1831		* @param  key key for which mapping should be removed
1832		* @return previous value associated with specified key, or <tt>null</tt>
1833	<	*         if there was no mapping for key.
1833	>	*         if there was no mapping for key
1834		*
1835		* @throws ClassCastException if the key cannot be compared with the keys
1836	<	*            currently in the map.
1837	<	* @throws NullPointerException if the key is <tt>null</tt>.
1836	>	*            currently in the map
1837	>	* @throws NullPointerException if the key is <tt>null</tt>
1838		*/
1839		public V remove(Object key) {
1840		return doRemove(key, null);
#	Line 1845 | Line 1845 | public class ConcurrentSkipListMap<K,V>
1845		* specified value.  This operation requires time linear in the
1846		* Map size.
1847		*
1848	<	* @param value value whose presence in this Map is to be tested.
1848	>	* @param value value whose presence in this Map is to be tested
1849		* @return  <tt>true</tt> if a mapping to <tt>value</tt> exists;
1850	<	*          <tt>false</tt> otherwise.
1851	<	* @throws  NullPointerException  if the value is <tt>null</tt>.
1852	<	*/
1850	>	*          <tt>false</tt> otherwise
1851	>	* @throws  NullPointerException  if the value is <tt>null</tt>
1852	>	*/
1853		public boolean containsValue(Object value) {
1854	<	if (value == null)
1854	>	if (value == null)
1855		throw new NullPointerException();
1856		for (Node<K,V> n = findFirst(); n != null; n = n.next) {
1857		V v = n.getValidValue();
#	Line 1875 | Line 1875 | public class ConcurrentSkipListMap<K,V>
1875		* will be inaccurate. Thus, this method is typically not very
1876		* useful in concurrent applications.
1877		*
1878	<	* @return  the number of elements in this map.
1878	>	* @return  the number of elements in this map
1879		*/
1880		public int size() {
1881		long count = 0;
#	Line 1883 | Line 1883 | public class ConcurrentSkipListMap<K,V>
1883		if (n.getValidValue() != null)
1884		++count;
1885		}
1886	<	return (count >= Integer.MAX_VALUE)? Integer.MAX_VALUE : (int)count;
1886	>	return (count >= Integer.MAX_VALUE) ? Integer.MAX_VALUE : (int)count;
1887		}
1888
1889		/**
1890		* Returns <tt>true</tt> if this map contains no key-value mappings.
1891	<	* @return <tt>true</tt> if this map contains no key-value mappings.
1891	>	* @return <tt>true</tt> if this map contains no key-value mappings
1892		*/
1893		public boolean isEmpty() {
1894		return findFirst() == null;
#	Line 1915 | Line 1915 | public class ConcurrentSkipListMap<K,V>
1915		* construction of the iterator, and may (but is not guaranteed to)
1916		* reflect any modifications subsequent to construction.
1917		*
1918	<	* @return a set view of the keys contained in this map.
1918	>	* @return a set view of the keys contained in this map
1919		*/
1920		public Set<K> keySet() {
1921		/*
#	Line 1946 | Line 1946 | public class ConcurrentSkipListMap<K,V>
1946		* construction of the iterator, and may (but is not guaranteed
1947		* to) reflect any modifications subsequent to construction.
1948		*
1949	<	* @return a set view of the keys contained in this map.
1949	>	* @return a set view of the keys contained in this map
1950		*/
1951		public Set<K> descendingKeySet() {
1952		/*
#	Line 1978 | Line 1978 | public class ConcurrentSkipListMap<K,V>
1978		* iterator, and may (but is not guaranteed to) reflect any
1979		* modifications subsequent to construction.
1980		*
1981	<	* @return a collection view of the values contained in this map.
1981	>	* @return a collection view of the values contained in this map
1982		*/
1983		public Collection<V> values() {
1984		Values vs = values;
#	Line 2005 | Line 2005 | public class ConcurrentSkipListMap<K,V>
2005		* <tt>iterator.next()</tt> do <em>not</em> support the
2006		* <tt>setValue</tt> operation.
2007		*
2008	<	* @return a collection view of the mappings contained in this map.
2008	>	* @return a collection view of the mappings contained in this map
2009		*/
2010		public Set<Map.Entry<K,V>> entrySet() {
2011		EntrySet es = entrySet;
#	Line 2032 | Line 2032 | public class ConcurrentSkipListMap<K,V>
2032		* <tt>iterator.next()</tt> do <em>not</em> support the
2033		* <tt>setValue</tt> operation.
2034		*
2035	<	* @return a collection view of the mappings contained in this map.
2035	>	* @return a collection view of the mappings contained in this map
2036		*/
2037		public Set<Map.Entry<K,V>> descendingEntrySet() {
2038		DescendingEntrySet es = descendingEntrySet;
#	Line 2052 | Line 2052 | public class ConcurrentSkipListMap<K,V>
2052		* operation may return misleading results if either map is
2053		* concurrently modified during execution of this method.
2054		*
2055	<	* @param o object to be compared for equality with this map.
2056	<	* @return <tt>true</tt> if the specified object is equal to this map.
2055	>	* @param o object to be compared for equality with this map
2056	>	* @return <tt>true</tt> if the specified object is equal to this map
2057		*/
2058		public boolean equals(Object o) {
2059	<	if (o == this)
2060	<	return true;
2061	<	if (!(o instanceof Map))
2062	<	return false;
2063	<	Map<K,V> t = (Map<K,V>) o;
2059	>	if (o == this)
2060	>	return true;
2061	>	if (!(o instanceof Map))
2062	>	return false;
2063	>	Map<K,V> t = (Map<K,V>) o;
2064		try {
2065	<	return (containsAllMappings(this, t) &&
2065	>	return (containsAllMappings(this, t) &&
2066		containsAllMappings(t, this));
2067	<	} catch(ClassCastException unused) {
2067	>	} catch (ClassCastException unused) {
2068		return false;
2069	<	} catch(NullPointerException unused) {
2069	>	} catch (NullPointerException unused) {
2070		return false;
2071		}
2072		}
#	Line 2080 | Line 2080 | public class ConcurrentSkipListMap<K,V>
2080		Entry<K,V> e = it.next();
2081		Object k = e.getKey();
2082		Object v = e.getValue();
2083	<	if (k == null || v == null || !v.equals(a.get(k)))
2083	>	if (k == null || v == null || !v.equals(a.get(k)))
2084		return false;
2085		}
2086		return true;
#	Line 2093 | Line 2093 | public class ConcurrentSkipListMap<K,V>
2093		* with a value, associate it with the given value.
2094		* This is equivalent to
2095		* <pre>
2096	<	*   if (!map.containsKey(key))
2097	<	*      return map.put(key, value);
2096	>	*   if (!map.containsKey(key))
2097	>	*     return map.put(key, value);
2098		*   else
2099	<	*      return map.get(key);
2099	>	*     return map.get(key);
2100		* </pre>
2101		* except that the action is performed atomically.
2102	<	* @param key key with which the specified value is to be associated.
2103	<	* @param value value to be associated with the specified key.
2102	>	* @param key key with which the specified value is to be associated
2103	>	* @param value value to be associated with the specified key
2104		* @return previous value associated with specified key, or <tt>null</tt>
2105	<	*         if there was no mapping for key.
2105	>	*         if there was no mapping for key
2106		*
2107		* @throws ClassCastException if the key cannot be compared with the keys
2108	<	*            currently in the map.
2109	<	* @throws NullPointerException if the key or value are <tt>null</tt>.
2108	>	*            currently in the map
2109	>	* @throws NullPointerException if the key or value are <tt>null</tt>
2110		*/
2111		public V putIfAbsent(K key, V value) {
2112	<	if (value == null)
2112	>	if (value == null)
2113		throw new NullPointerException();
2114		return doPut(key, value, true);
2115		}
2116
2117		/**
2118	<	* Remove entry for key only if currently mapped to given value.
2118	>	* Removes entry for key only if currently mapped to given value.
2119		* Acts as
2120	<	* <pre>
2120	>	* <pre>
2121		*  if ((map.containsKey(key) && map.get(key).equals(value)) {
2122		*     map.remove(key);
2123		*     return true;
2124		* } else return false;
2125		* </pre>
2126		* except that the action is performed atomically.
2127	<	* @param key key with which the specified value is associated.
2128	<	* @param value value associated with the specified key.
2127	>	* @param key key with which the specified value is associated
2128	>	* @param value value associated with the specified key
2129		* @return true if the value was removed, false otherwise
2130		* @throws ClassCastException if the key cannot be compared with the keys
2131	<	*            currently in the map.
2132	<	* @throws NullPointerException if the key or value are <tt>null</tt>.
2131	>	*            currently in the map
2132	>	* @throws NullPointerException if the key or value are <tt>null</tt>
2133		*/
2134		public boolean remove(Object key, Object value) {
2135	<	if (value == null)
2135	>	if (value == null)
2136		throw new NullPointerException();
2137		return doRemove(key, value) != null;
2138		}
#	Line 2140 | Line 2140 | public class ConcurrentSkipListMap<K,V>
2140		/**
2141		* Replace entry for key only if currently mapped to given value.
2142		* Acts as
2143	<	* <pre>
2143	>	* <pre>
2144		*  if ((map.containsKey(key) && map.get(key).equals(oldValue)) {
2145		*     map.put(key, newValue);
2146		*     return true;
2147		* } else return false;
2148		* </pre>
2149		* except that the action is performed atomically.
2150	<	* @param key key with which the specified value is associated.
2151	<	* @param oldValue value expected to be associated with the specified key.
2152	<	* @param newValue value to be associated with the specified key.
2150	>	* @param key key with which the specified value is associated
2151	>	* @param oldValue value expected to be associated with the specified key
2152	>	* @param newValue value to be associated with the specified key
2153		* @return true if the value was replaced
2154		* @throws ClassCastException if the key cannot be compared with the keys
2155	<	*            currently in the map.
2155	>	*            currently in the map
2156		* @throws NullPointerException if key, oldValue or newValue are
2157	<	* <tt>null</tt>.
2157	>	* <tt>null</tt>
2158		*/
2159		public boolean replace(K key, V oldValue, V newValue) {
2160	<	if (oldValue == null || newValue == null)
2160	>	if (oldValue == null || newValue == null)
2161		throw new NullPointerException();
2162		Comparable<K> k = comparable(key);
2163		for (;;) {
#	Line 2177 | Line 2177 | public class ConcurrentSkipListMap<K,V>
2177		/**
2178		* Replace entry for key only if currently mapped to some value.
2179		* Acts as
2180	<	* <pre>
2180	>	* <pre>
2181		*  if ((map.containsKey(key)) {
2182		*     return map.put(key, value);
2183		* } else return null;
2184		* </pre>
2185		* except that the action is performed atomically.
2186	<	* @param key key with which the specified value is associated.
2187	<	* @param value value to be associated with the specified key.
2186	>	* @param key key with which the specified value is associated
2187	>	* @param value value to be associated with the specified key
2188		* @return previous value associated with specified key, or <tt>null</tt>
2189	<	*         if there was no mapping for key.
2189	>	*         if there was no mapping for key
2190		* @throws ClassCastException if the key cannot be compared with the keys
2191	<	*            currently in the map.
2192	<	* @throws NullPointerException if the key or value are <tt>null</tt>.
2191	>	*            currently in the map
2192	>	* @throws NullPointerException if the key or value are <tt>null</tt>
2193		*/
2194		public V replace(K key, V value) {
2195	<	if (value == null)
2195	>	if (value == null)
2196		throw new NullPointerException();
2197		Comparable<K> k = comparable(key);
2198		for (;;) {
#	Line 2221 | Line 2221 | public class ConcurrentSkipListMap<K,V>
2221		/**
2222		* Returns the first (lowest) key currently in this map.
2223		*
2224	<	* @return the first (lowest) key currently in this map.
2225	<	* @throws    NoSuchElementException Map is empty.
2224	>	* @return the first (lowest) key currently in this map
2225	>	* @throws    NoSuchElementException Map is empty
2226		*/
2227	<	public K firstKey() {
2227	>	public K firstKey() {
2228		Node<K,V> n = findFirst();
2229		if (n == null)
2230		throw new NoSuchElementException();
#	Line 2234 | Line 2234 | public class ConcurrentSkipListMap<K,V>
2234		/**
2235		* Returns the last (highest) key currently in this map.
2236		*
2237	<	* @return the last (highest) key currently in this map.
2238	<	* @throws    NoSuchElementException Map is empty.
2237	>	* @return the last (highest) key currently in this map
2238	>	* @throws    NoSuchElementException Map is empty
2239		*/
2240		public K lastKey() {
2241		Node<K,V> n = findLast();
#	Line 2250 | Line 2250 | public class ConcurrentSkipListMap<K,V>
2250		* <tt>fromKey</tt> and <tt>toKey</tt> are equal, the returned sorted map
2251		* is empty.)  The returned sorted map is backed by this map, so changes
2252		* in the returned sorted map are reflected in this map, and vice-versa.
2253	<
2254	<	* @param fromKey low endpoint (inclusive) of the subMap.
2255	<	* @param toKey high endpoint (exclusive) of the subMap.
2253	>	*
2254	>	* @param fromKey low endpoint (inclusive) of the subMap
2255	>	* @param toKey high endpoint (exclusive) of the subMap
2256		*
2257		* @return a view of the portion of this map whose keys range from
2258	<	* <tt>fromKey</tt>, inclusive, to <tt>toKey</tt>, exclusive.
2258	>	* <tt>fromKey</tt>, inclusive, to <tt>toKey</tt>, exclusive
2259		*
2260		* @throws ClassCastException if <tt>fromKey</tt> and <tt>toKey</tt>
2261		*         cannot be compared to one another using this map's comparator
2262	<	*         (or, if the map has no comparator, using natural ordering).
2262	>	*         (or, if the map has no comparator, using natural ordering)
2263		* @throws IllegalArgumentException if <tt>fromKey</tt> is greater than
2264	<	*         <tt>toKey</tt>.
2264	>	*         <tt>toKey</tt>
2265		* @throws NullPointerException if <tt>fromKey</tt> or <tt>toKey</tt> is
2266	<	*               <tt>null</tt>.
2266	>	*               <tt>null</tt>
2267		*/
2268		public ConcurrentNavigableMap<K,V> subMap(K fromKey, K toKey) {
2269		if (fromKey == null || toKey == null)
#	Line 2276 | Line 2276 | public class ConcurrentSkipListMap<K,V>
2276		* strictly less than <tt>toKey</tt>.  The returned sorted map is
2277		* backed by this map, so changes in the returned sorted map are
2278		* reflected in this map, and vice-versa.
2279	<	* @param toKey high endpoint (exclusive) of the headMap.
2279	>	* @param toKey high endpoint (exclusive) of the headMap
2280		* @return a view of the portion of this map whose keys are
2281	<	* strictly less than <tt>toKey</tt>.
2281	>	* strictly less than <tt>toKey</tt>
2282		*
2283		* @throws ClassCastException if <tt>toKey</tt> is not compatible
2284		* with this map's comparator (or, if the map has no comparator,
2285	<	* if <tt>toKey</tt> does not implement <tt>Comparable</tt>).
2286	<	* @throws NullPointerException if <tt>toKey</tt> is <tt>null</tt>.
2285	>	* if <tt>toKey</tt> does not implement <tt>Comparable</tt>)
2286	>	* @throws NullPointerException if <tt>toKey</tt> is <tt>null</tt>
2287		*/
2288		public ConcurrentNavigableMap<K,V> headMap(K toKey) {
2289		if (toKey == null)
#	Line 2296 | Line 2296 | public class ConcurrentSkipListMap<K,V>
2296		* greater than or equal to <tt>fromKey</tt>.  The returned sorted
2297		* map is backed by this map, so changes in the returned sorted
2298		* map are reflected in this map, and vice-versa.
2299	<	* @param fromKey low endpoint (inclusive) of the tailMap.
2299	>	* @param fromKey low endpoint (inclusive) of the tailMap
2300		* @return a view of the portion of this map whose keys are
2301	<	* greater than or equal to <tt>fromKey</tt>.
2301	>	* greater than or equal to <tt>fromKey</tt>
2302		* @throws ClassCastException if <tt>fromKey</tt> is not
2303		* compatible with this map's comparator (or, if the map has no
2304		* comparator, if <tt>fromKey</tt> does not implement
2305	<	* <tt>Comparable</tt>).
2306	<	* @throws NullPointerException if <tt>fromKey</tt> is <tt>null</tt>.
2305	>	* <tt>Comparable</tt>)
2306	>	* @throws NullPointerException if <tt>fromKey</tt> is <tt>null</tt>
2307		*/
2308	<	public ConcurrentNavigableMap<K,V>  tailMap(K fromKey) {
2308	>	public ConcurrentNavigableMap<K,V> tailMap(K fromKey) {
2309		if (fromKey == null)
2310		throw new NullPointerException();
2311		return new ConcurrentSkipListSubMap(this, fromKey, null);
#	Line 2318 | Line 2318 | public class ConcurrentSkipListMap<K,V>
2318		* greater than or equal to the given key, or <tt>null</tt> if
2319		* there is no such entry. The returned entry does <em>not</em>
2320		* support the <tt>Entry.setValue</tt> method.
2321	<	*
2322	<	* @param key the key.
2321	>	*
2322	>	* @param key the key
2323		* @return an Entry associated with ceiling of given key, or
2324	<	* <tt>null</tt> if there is no such Entry.
2324	>	* <tt>null</tt> if there is no such Entry
2325		* @throws ClassCastException if key cannot be compared with the
2326	<	* keys currently in the map.
2327	<	* @throws NullPointerException if key is <tt>null</tt>.
2326	>	* keys currently in the map
2327	>	* @throws NullPointerException if key is <tt>null</tt>
2328		*/
2329		public Map.Entry<K,V> ceilingEntry(K key) {
2330		return getNear(key, GT|EQ);
#	Line 2333 | Line 2333 | public class ConcurrentSkipListMap<K,V>
2333		/**
2334		* Returns least key greater than or equal to the given key, or
2335		* <tt>null</tt> if there is no such key.
2336	<	*
2337	<	* @param key the key.
2336	>	*
2337	>	* @param key the key
2338		* @return the ceiling key, or <tt>null</tt>
2339	<	* if there is no such key.
2339	>	* if there is no such key
2340		* @throws ClassCastException if key cannot be compared with the keys
2341	<	*            currently in the map.
2342	<	* @throws NullPointerException if key is <tt>null</tt>.
2341	>	*            currently in the map
2342	>	* @throws NullPointerException if key is <tt>null</tt>
2343		*/
2344		public K ceilingKey(K key) {
2345		Node<K,V> n = findNear(key, GT|EQ);
2346	<	return (n == null)? null : n.key;
2346	>	return (n == null) ? null : n.key;
2347		}
2348
2349		/**
#	Line 2351 | Line 2351 | public class ConcurrentSkipListMap<K,V>
2351		* key strictly less than the given key, or <tt>null</tt> if there is no
2352		* such entry. The returned entry does <em>not</em> support
2353		* the <tt>Entry.setValue</tt> method.
2354	<	*
2355	<	* @param key the key.
2354	>	*
2355	>	* @param key the key
2356		* @return an Entry with greatest key less than the given
2357	<	* key, or <tt>null</tt> if there is no such Entry.
2357	>	* key, or <tt>null</tt> if there is no such Entry
2358		* @throws ClassCastException if key cannot be compared with the keys
2359	<	*            currently in the map.
2360	<	* @throws NullPointerException if key is <tt>null</tt>.
2359	>	*            currently in the map
2360	>	* @throws NullPointerException if key is <tt>null</tt>
2361		*/
2362		public Map.Entry<K,V> lowerEntry(K key) {
2363		return getNear(key, LT);
#	Line 2366 | Line 2366 | public class ConcurrentSkipListMap<K,V>
2366		/**
2367		* Returns the greatest key strictly less than the given key, or
2368		* <tt>null</tt> if there is no such key.
2369	<	*
2370	<	* @param key the key.
2369	>	*
2370	>	* @param key the key
2371		* @return the greatest key less than the given
2372	<	* key, or <tt>null</tt> if there is no such key.
2372	>	* key, or <tt>null</tt> if there is no such key
2373		* @throws ClassCastException if key cannot be compared with the keys
2374	<	*            currently in the map.
2375	<	* @throws NullPointerException if key is <tt>null</tt>.
2374	>	*            currently in the map
2375	>	* @throws NullPointerException if key is <tt>null</tt>
2376		*/
2377		public K lowerKey(K key) {
2378		Node<K,V> n = findNear(key, LT);
2379	<	return (n == null)? null : n.key;
2379	>	return (n == null) ? null : n.key;
2380		}
2381
2382		/**
#	Line 2384 | Line 2384 | public class ConcurrentSkipListMap<K,V>
2384		* less than or equal to the given key, or <tt>null</tt> if there
2385		* is no such entry. The returned entry does <em>not</em> support
2386		* the <tt>Entry.setValue</tt> method.
2387	<	*
2388	<	* @param key the key.
2387	>	*
2388	>	* @param key the key
2389		* @return an Entry associated with floor of given key, or <tt>null</tt>
2390	<	* if there is no such Entry.
2390	>	* if there is no such Entry
2391		* @throws ClassCastException if key cannot be compared with the keys
2392	<	*            currently in the map.
2393	<	* @throws NullPointerException if key is <tt>null</tt>.
2392	>	*            currently in the map
2393	>	* @throws NullPointerException if key is <tt>null</tt>
2394		*/
2395		public Map.Entry<K,V> floorEntry(K key) {
2396		return getNear(key, LT|EQ);
#	Line 2400 | Line 2400 | public class ConcurrentSkipListMap<K,V>
2400		* Returns the greatest key
2401		* less than or equal to the given key, or <tt>null</tt> if there
2402		* is no such key.
2403	<	*
2404	<	* @param key the key.
2403	>	*
2404	>	* @param key the key
2405		* @return the floor of given key, or <tt>null</tt> if there is no
2406	<	* such key.
2406	>	* such key
2407		* @throws ClassCastException if key cannot be compared with the keys
2408	<	*            currently in the map.
2409	<	* @throws NullPointerException if key is <tt>null</tt>.
2408	>	*            currently in the map
2409	>	* @throws NullPointerException if key is <tt>null</tt>
2410		*/
2411		public K floorKey(K key) {
2412		Node<K,V> n = findNear(key, LT|EQ);
2413	<	return (n == null)? null : n.key;
2413	>	return (n == null) ? null : n.key;
2414		}
2415
2416		/**
#	Line 2418 | Line 2418 | public class ConcurrentSkipListMap<K,V>
2418		* strictly greater than the given key, or <tt>null</tt> if there
2419		* is no such entry. The returned entry does <em>not</em> support
2420		* the <tt>Entry.setValue</tt> method.
2421	<	*
2422	<	* @param key the key.
2421	>	*
2422	>	* @param key the key
2423		* @return an Entry with least key greater than the given key, or
2424	<	* <tt>null</tt> if there is no such Entry.
2424	>	* <tt>null</tt> if there is no such Entry
2425		* @throws ClassCastException if key cannot be compared with the keys
2426	<	*            currently in the map.
2427	<	* @throws NullPointerException if key is <tt>null</tt>.
2426	>	*            currently in the map
2427	>	* @throws NullPointerException if key is <tt>null</tt>
2428		*/
2429		public Map.Entry<K,V> higherEntry(K key) {
2430		return getNear(key, GT);
#	Line 2433 | Line 2433 | public class ConcurrentSkipListMap<K,V>
2433		/**
2434		* Returns the least key strictly greater than the given key, or
2435		* <tt>null</tt> if there is no such key.
2436	<	*
2437	<	* @param key the key.
2436	>	*
2437	>	* @param key the key
2438		* @return the least key greater than the given key, or
2439	<	* <tt>null</tt> if there is no such key.
2439	>	* <tt>null</tt> if there is no such key
2440		* @throws ClassCastException if key cannot be compared with the keys
2441	<	*            currently in the map.
2442	<	* @throws NullPointerException if key is <tt>null</tt>.
2441	>	*            currently in the map
2442	>	* @throws NullPointerException if key is <tt>null</tt>
2443		*/
2444		public K higherKey(K key) {
2445		Node<K,V> n = findNear(key, GT);
2446	<	return (n == null)? null : n.key;
2446	>	return (n == null) ? null : n.key;
2447		}
2448
2449		/**
#	Line 2451 | Line 2451 | public class ConcurrentSkipListMap<K,V>
2451		* key in this map, or <tt>null</tt> if the map is empty.
2452		* The returned entry does <em>not</em> support
2453		* the <tt>Entry.setValue</tt> method.
2454	<	*
2455	<	* @return an Entry with least key, or <tt>null</tt>
2456	<	* if the map is empty.
2454	>	*
2455	>	* @return an Entry with least key, or <tt>null</tt>
2456	>	* if the map is empty
2457		*/
2458		public Map.Entry<K,V> firstEntry() {
2459		for (;;) {
2460		Node<K,V> n = findFirst();
2461	<	if (n == null)
2461	>	if (n == null)
2462		return null;
2463		SnapshotEntry<K,V> e = n.createSnapshot();
2464		if (e != null)
#	Line 2471 | Line 2471 | public class ConcurrentSkipListMap<K,V>
2471		* key in this map, or <tt>null</tt> if the map is empty.
2472		* The returned entry does <em>not</em> support
2473		* the <tt>Entry.setValue</tt> method.
2474	<	*
2474	>	*
2475		* @return an Entry with greatest key, or <tt>null</tt>
2476	<	* if the map is empty.
2476	>	* if the map is empty
2477		*/
2478		public Map.Entry<K,V> lastEntry() {
2479		for (;;) {
2480		Node<K,V> n = findLast();
2481	<	if (n == null)
2481	>	if (n == null)
2482		return null;
2483		SnapshotEntry<K,V> e = n.createSnapshot();
2484		if (e != null)
#	Line 2491 | Line 2491 | public class ConcurrentSkipListMap<K,V>
2491		* the least key in this map, or <tt>null</tt> if the map is empty.
2492		* The returned entry does <em>not</em> support
2493		* the <tt>Entry.setValue</tt> method.
2494	<	*
2494	>	*
2495		* @return the removed first entry of this map, or <tt>null</tt>
2496	<	* if the map is empty.
2496	>	* if the map is empty
2497		*/
2498		public Map.Entry<K,V> pollFirstEntry() {
2499		return (SnapshotEntry<K,V>)doRemoveFirst(false);
#	Line 2504 | Line 2504 | public class ConcurrentSkipListMap<K,V>
2504		* the greatest key in this map, or <tt>null</tt> if the map is empty.
2505		* The returned entry does <em>not</em> support
2506		* the <tt>Entry.setValue</tt> method.
2507	<	*
2507	>	*
2508		* @return the removed last entry of this map, or <tt>null</tt>
2509	<	* if the map is empty.
2509	>	* if the map is empty
2510		*/
2511		public Map.Entry<K,V> pollLastEntry() {
2512		return (SnapshotEntry<K,V>)doRemoveLast(false);
#	Line 2517 | Line 2517 | public class ConcurrentSkipListMap<K,V>
2517
2518		/**
2519		* Base of ten kinds of iterator classes:
2520	<	*   ascending:  {map, submap} X {key, value, entry}
2521	<	*   descending: {map, submap} X {key, entry}
2520	>	*   ascending:  {map, submap} X {key, value, entry}
2521	>	*   descending: {map, submap} X {key, entry}
2522		*/
2523		abstract class Iter {
2524		/** the last node returned by next() */
2525		Node<K,V> last;
2526		/** the next node to return from next(); */
2527		Node<K,V> next;
2528	<	/** Cache of next value field to maintain weak consistency */
2529	<	Object nextValue;
2528	>	/** Cache of next value field to maintain weak consistency */
2529	>	Object nextValue;
2530
2531		Iter() {}
2532
2533	<	public final boolean hasNext() {
2534	<	return next != null;
2533	>	public final boolean hasNext() {
2534	>	return next != null;
2535		}
2536
2537		/** initialize ascending iterator for entire range  */
2538		final void initAscending() {
2539		for (;;) {
2540	<	next = findFirst();
2540	>	next = findFirst();
2541		if (next == null)
2542		break;
2543		nextValue = next.value;
#	Line 2546 | Line 2546 | public class ConcurrentSkipListMap<K,V>
2546		}
2547		}
2548
2549	<	/**
2549	>	/**
2550		* initialize ascending iterator starting at given least key,
2551		* or first node if least is <tt>null</tt>, but not greater or
2552		* equal to fence, or end if fence is <tt>null</tt>.
2553		*/
2554	<	final void initAscending(K least, K fence) {
2554	>	final void initAscending(K least, K fence) {
2555		for (;;) {
2556	<	next = findCeiling(least);
2556	>	next = findCeiling(least);
2557		if (next == null)
2558		break;
2559		nextValue = next.value;
#	Line 2571 | Line 2571 | public class ConcurrentSkipListMap<K,V>
2571		if ((last = next) == null)
2572		throw new NoSuchElementException();
2573		for (;;) {
2574	<	next = next.next;
2574	>	next = next.next;
2575		if (next == null)
2576		break;
2577		nextValue = next.value;
#	Line 2587 | Line 2587 | public class ConcurrentSkipListMap<K,V>
2587		if ((last = next) == null)
2588		throw new NoSuchElementException();
2589		for (;;) {
2590	<	next = next.next;
2590	>	next = next.next;
2591		if (next == null)
2592		break;
2593		nextValue = next.value;
#	Line 2604 | Line 2604 | public class ConcurrentSkipListMap<K,V>
2604		/** initialize descending iterator for entire range  */
2605		final void initDescending() {
2606		for (;;) {
2607	<	next = findLast();
2607	>	next = findLast();
2608		if (next == null)
2609		break;
2610		nextValue = next.value;
#	Line 2613 | Line 2613 | public class ConcurrentSkipListMap<K,V>
2613		}
2614		}
2615
2616	<	/**
2616	>	/**
2617		* initialize descending iterator starting at key less
2618		* than or equal to given fence key, or
2619		* last node if fence is <tt>null</tt>, but not less than
2620		* least, or beginning if lest is <tt>null</tt>.
2621		*/
2622	<	final void initDescending(K least, K fence) {
2622	>	final void initDescending(K least, K fence) {
2623		for (;;) {
2624	<	next = findLower(fence);
2624	>	next = findLower(fence);
2625		if (next == null)
2626		break;
2627		nextValue = next.value;
#	Line 2641 | Line 2641 | public class ConcurrentSkipListMap<K,V>
2641		throw new NoSuchElementException();
2642		K k = last.key;
2643		for (;;) {
2644	<	next = findNear(k, LT);
2644	>	next = findNear(k, LT);
2645		if (next == null)
2646		break;
2647		nextValue = next.value;
#	Line 2658 | Line 2658 | public class ConcurrentSkipListMap<K,V>
2658		throw new NoSuchElementException();
2659		K k = last.key;
2660		for (;;) {
2661	<	next = findNear(k, LT);
2661	>	next = findNear(k, LT);
2662		if (next == null)
2663		break;
2664		nextValue = next.value;
#	Line 2687 | Line 2687 | public class ConcurrentSkipListMap<K,V>
2687		ValueIterator() {
2688		initAscending();
2689		}
2690	<	public V next() {
2690	>	public V next() {
2691		Object v = nextValue;
2692		ascend();
2693		return (V)v;
#	Line 2698 | Line 2698 | public class ConcurrentSkipListMap<K,V>
2698		KeyIterator() {
2699		initAscending();
2700		}
2701	<	public K next() {
2701	>	public K next() {
2702		Node<K,V> n = next;
2703		ascend();
2704		return n.key;
#	Line 2712 | Line 2712 | public class ConcurrentSkipListMap<K,V>
2712		this.fence = fence;
2713		}
2714
2715	<	public V next() {
2715	>	public V next() {
2716		Object v = nextValue;
2717		ascend(fence);
2718		return (V)v;
#	Line 2726 | Line 2726 | public class ConcurrentSkipListMap<K,V>
2726		this.fence = fence;
2727		}
2728
2729	<	public K next() {
2729	>	public K next() {
2730		Node<K,V> n = next;
2731		ascend(fence);
2732		return n.key;
#	Line 2737 | Line 2737 | public class ConcurrentSkipListMap<K,V>
2737		DescendingKeyIterator() {
2738		initDescending();
2739		}
2740	<	public K next() {
2740	>	public K next() {
2741		Node<K,V> n = next;
2742		descend();
2743		return n.key;
#	Line 2751 | Line 2751 | public class ConcurrentSkipListMap<K,V>
2751		this.least = least;
2752		}
2753
2754	<	public K next() {
2754	>	public K next() {
2755		Node<K,V> n = next;
2756		descend(least);
2757		return n.key;
#	Line 2767 | Line 2767 | public class ConcurrentSkipListMap<K,V>
2767		/** Cache of last value returned */
2768		Object lastValue;
2769
2770	<	EntryIter() {
2770	>	EntryIter() {
2771		}
2772
2773		public K getKey() {
#	Line 2781 | Line 2781 | public class ConcurrentSkipListMap<K,V>
2781		Object v = lastValue;
2782		if (last == null || v == null)
2783		throw new IllegalStateException();
2784	<	return (V)v;
2784	>	return (V)v;
2785		}
2786
2787		public V setValue(V value) {
#	Line 2810 | Line 2810 | public class ConcurrentSkipListMap<K,V>
2810		// If not acting as entry, just use default.
2811		if (last == null)
2812		return super.toString();
2813	<	return getKey() + "=" + getValue();
2813	>	return getKey() + "=" + getValue();
2814		}
2815		}
2816
2817	<	final class EntryIterator extends EntryIter
2817	>	final class EntryIterator extends EntryIter
2818		implements Iterator<Map.Entry<K,V>> {
2819	<	EntryIterator() {
2820	<	initAscending();
2819	>	EntryIterator() {
2820	>	initAscending();
2821		}
2822	<	public Map.Entry<K,V> next() {
2822	>	public Map.Entry<K,V> next() {
2823		lastValue = nextValue;
2824		ascend();
2825		return this;
2826		}
2827		}
2828
2829	<	final class SubMapEntryIterator extends EntryIter
2829	>	final class SubMapEntryIterator extends EntryIter
2830		implements Iterator<Map.Entry<K,V>> {
2831		final K fence;
2832		SubMapEntryIterator(K least, K fence) {
#	Line 2834 | Line 2834 | public class ConcurrentSkipListMap<K,V>
2834		this.fence = fence;
2835		}
2836
2837	<	public Map.Entry<K,V> next() {
2837	>	public Map.Entry<K,V> next() {
2838		lastValue = nextValue;
2839		ascend(fence);
2840		return this;
2841		}
2842		}
2843
2844	<	final class DescendingEntryIterator extends EntryIter
2844	>	final class DescendingEntryIterator extends EntryIter
2845		implements Iterator<Map.Entry<K,V>>  {
2846	<	DescendingEntryIterator() {
2847	<	initDescending();
2846	>	DescendingEntryIterator() {
2847	>	initDescending();
2848		}
2849	<	public Map.Entry<K,V> next() {
2849	>	public Map.Entry<K,V> next() {
2850		lastValue = nextValue;
2851		descend();
2852		return this;
2853		}
2854		}
2855
2856	<	final class DescendingSubMapEntryIterator extends EntryIter
2856	>	final class DescendingSubMapEntryIterator extends EntryIter
2857		implements Iterator<Map.Entry<K,V>>  {
2858		final K least;
2859		DescendingSubMapEntryIterator(K least, K fence) {
#	Line 2861 | Line 2861 | public class ConcurrentSkipListMap<K,V>
2861		this.least = least;
2862		}
2863
2864	<	public Map.Entry<K,V> next() {
2864	>	public Map.Entry<K,V> next() {
2865		lastValue = nextValue;
2866		descend(least);
2867		return this;
#	Line 2985 | Line 2985 | public class ConcurrentSkipListMap<K,V>
2985		if (!(o instanceof Map.Entry))
2986		return false;
2987		Map.Entry<K,V> e = (Map.Entry<K,V>)o;
2988	<	return ConcurrentSkipListMap.this.remove(e.getKey(),
2988	>	return ConcurrentSkipListMap.this.remove(e.getKey(),
2989		e.getValue());
2990		}
2991		public boolean isEmpty() {
#	Line 3000 | Line 3000 | public class ConcurrentSkipListMap<K,V>
3000
3001		public Object[] toArray() {
3002		Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>();
3003	<	for (Map.Entry e : this)
3003	>	for (Map.Entry e : this)
3004		c.add(new SnapshotEntry(e.getKey(), e.getValue()));
3005		return c.toArray();
3006		}
3007		public <T> T[] toArray(T[] a) {
3008		Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>();
3009	<	for (Map.Entry e : this)
3009	>	for (Map.Entry e : this)
3010		c.add(new SnapshotEntry(e.getKey(), e.getValue()));
3011		return c.toArray(a);
3012		}
#	Line 3036 | Line 3036 | public class ConcurrentSkipListMap<K,V>
3036		/** Underlying map */
3037		private final ConcurrentSkipListMap<K,V> m;
3038		/** lower bound key, or null if from start */
3039	<	private final K least;
3039	>	private final K least;
3040		/** upper fence key, or null if to end */
3041	<	private final K fence;
3041	>	private final K fence;
3042		// Lazily initialized view holders
3043		private transient Set<K> keySetView;
3044		private transient Set<Map.Entry<K,V>> entrySetView;
#	Line 3047 | Line 3047 | public class ConcurrentSkipListMap<K,V>
3047		private transient Set<Map.Entry<K,V>> descendingEntrySetView;
3048
3049		/**
3050	<	* Creates a new submap.
3050	>	* Creates a new submap.
3051		* @param least inclusive least value, or <tt>null</tt> if from start
3052		* @param fence exclusive upper bound or <tt>null</tt> if to end
3053	<	* @throws IllegalArgumentException if least and fence nonnull
3053	>	* @throws IllegalArgumentException if least and fence non-null
3054		*  and least greater than fence
3055		*/
3056	<	ConcurrentSkipListSubMap(ConcurrentSkipListMap<K,V> map,
3056	>	ConcurrentSkipListSubMap(ConcurrentSkipListMap<K,V> map,
3057		K least, K fence) {
3058	<	if (least != null &&
3059	<	fence != null &&
3058	>	if (least != null &&
3059	>	fence != null &&
3060		map.compare(least, fence) > 0)
3061		throw new IllegalArgumentException("inconsistent range");
3062		this.m = map;
#	Line 3083 | Line 3083 | public class ConcurrentSkipListMap<K,V>
3083		}
3084
3085		boolean isBeforeEnd(ConcurrentSkipListMap.Node<K,V> n) {
3086	<	return (n != null &&
3087	<	(fence == null ||
3086	>	return (n != null &&
3087	>	(fence == null ||
3088		n.key == null || // pass by markers and headers
3089		m.compare(fence, n.key) > 0));
3090		}
#	Line 3128 | Line 3128 | public class ConcurrentSkipListMap<K,V>
3128
3129		public V get(Object key) {
3130		K k = (K)key;
3131	<	return ((!inHalfOpenRange(k)) ? null : m.get(k));
3131	>	return (!inHalfOpenRange(k)) ? null : m.get(k);
3132		}
3133
3134		public V put(K key, V value) {
#	Line 3138 | Line 3138 | public class ConcurrentSkipListMap<K,V>
3138
3139		public V remove(Object key) {
3140		K k = (K)key;
3141	<	return (!inHalfOpenRange(k))? null : m.remove(k);
3141	>	return (!inHalfOpenRange(k)) ? null : m.remove(k);
3142		}
3143
3144		public int size() {
3145		long count = 0;
3146	<	for (ConcurrentSkipListMap.Node<K,V> n = firstNode();
3147	<	isBeforeEnd(n);
3146	>	for (ConcurrentSkipListMap.Node<K,V> n = firstNode();
3147	>	isBeforeEnd(n);
3148		n = n.next) {
3149		if (n.getValidValue() != null)
3150		++count;
3151		}
3152	<	return count >= Integer.MAX_VALUE? Integer.MAX_VALUE : (int)count;
3152	>	return (count >= Integer.MAX_VALUE) ?
3153	>	Integer.MAX_VALUE : (int)count;
3154		}
3155
3156		public boolean isEmpty() {
#	Line 3157 | Line 3158 | public class ConcurrentSkipListMap<K,V>
3158		}
3159
3160		public boolean containsValue(Object value) {
3161	<	if (value == null)
3161	>	if (value == null)
3162		throw new NullPointerException();
3163	<	for (ConcurrentSkipListMap.Node<K,V> n = firstNode();
3164	<	isBeforeEnd(n);
3163	>	for (ConcurrentSkipListMap.Node<K,V> n = firstNode();
3164	>	isBeforeEnd(n);
3165		n = n.next) {
3166		V v = n.getValidValue();
3167		if (v != null && value.equals(v))
#	Line 3170 | Line 3171 | public class ConcurrentSkipListMap<K,V>
3171		}
3172
3173		public void clear() {
3174	<	for (ConcurrentSkipListMap.Node<K,V> n = firstNode();
3175	<	isBeforeEnd(n);
3174	>	for (ConcurrentSkipListMap.Node<K,V> n = firstNode();
3175	>	isBeforeEnd(n);
3176		n = n.next) {
3177		if (n.getValidValue() != null)
3178		m.remove(n.key);
#	Line 3240 | Line 3241 | public class ConcurrentSkipListMap<K,V>
3241		return new ConcurrentSkipListSubMap(m, least, toKey);
3242		}
3243
3244	<	public  ConcurrentNavigableMap<K,V> tailMap(K fromKey) {
3244	>	public ConcurrentNavigableMap<K,V> tailMap(K fromKey) {
3245		if (fromKey == null)
3246		throw new NullPointerException();
3247		if (!inOpenRange(fromKey))
#	Line 3280 | Line 3281 | public class ConcurrentSkipListMap<K,V>
3281		m.getNear(key, m.LT|m.EQ, least, fence, true);
3282		}
3283
3284	<
3284	>
3285		public Map.Entry<K,V> higherEntry(K key) {
3286		return (SnapshotEntry<K,V>)
3287		m.getNear(key, m.GT, least, fence, false);
#	Line 3294 | Line 3295 | public class ConcurrentSkipListMap<K,V>
3295		public Map.Entry<K,V> firstEntry() {
3296		for (;;) {
3297		ConcurrentSkipListMap.Node<K,V> n = firstNode();
3298	<	if (!isBeforeEnd(n))
3298	>	if (!isBeforeEnd(n))
3299		return null;
3300		Map.Entry<K,V> e = n.createSnapshot();
3301		if (e != null)
#	Line 3436 | Line 3437 | public class ConcurrentSkipListMap<K,V>
3437		}
3438		public Object[] toArray() {
3439		Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>();
3440	<	for (Map.Entry e : this)
3440	>	for (Map.Entry e : this)
3441		c.add(new SnapshotEntry(e.getKey(), e.getValue()));
3442		return c.toArray();
3443		}
3444		public <T> T[] toArray(T[] a) {
3445		Collection<Map.Entry<K,V>> c = new ArrayList<Map.Entry<K,V>>();
3446	<	for (Map.Entry e : this)
3446	>	for (Map.Entry e : this)
3447		c.add(new SnapshotEntry(e.getKey(), e.getValue()));
3448		return c.toArray(a);
3449		}

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