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Comparing jsr166/src/jsr166x/ConcurrentSkipListMap.java (file contents):
Revision 1.8 by jsr166, Mon Nov 16 04:16:42 2009 UTC vs.
Revision 1.35 by jsr166, Thu Sep 3 22:54:46 2015 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;
#	Line 20 | Line 20 | import java.util.concurrent.atomic.*;
20		* <p>This class implements a concurrent variant of <a
21		* href="http://www.cs.umd.edu/~pugh/">SkipLists</a> providing
22		* expected average <i>log(n)</i> time cost for the
23	<	* <tt>containsKey</tt>, <tt>get</tt>, <tt>put</tt> and
24	<	* <tt>remove</tt> operations and their variants.  Insertion, removal,
23	>	* {@code containsKey}, {@code get}, {@code put} and
24	>	* {@code remove} operations and their variants.  Insertion, removal,
25		* update, and access operations safely execute concurrently by
26		* multiple threads. Iterators are <i>weakly consistent</i>, returning
27		* elements reflecting the state of the map at some point at or since
#	Line 30 | Line 30 | import java.util.concurrent.atomic.*;
30		* other operations. Ascending key ordered views and their iterators
31		* are faster than descending ones.
32		*
33	<	* <p>All <tt>Map.Entry</tt> pairs returned by methods in this class
33	>	* <p>All {@code Map.Entry} pairs returned by methods in this class
34		* and its views represent snapshots of mappings at the time they were
35	<	* produced. They do <em>not</em> support the <tt>Entry.setValue</tt>
35	>	* produced. They do <em>not</em> support the {@code Entry.setValue}
36		* method. (Note however that it is possible to change mappings in the
37	<	* associated map using <tt>put</tt>, <tt>putIfAbsent</tt>, or
38	<	* <tt>replace</tt>, depending on exactly which effect you need.)
37	>	* associated map using {@code put}, {@code putIfAbsent}, or
38	>	* {@code replace}, depending on exactly which effect you need.)
39		*
40	<	* <p>Beware that, unlike in most collections, the <tt>size</tt>
40	>	* <p>Beware that, unlike in most collections, the {@code size}
41		* method is <em>not</em> a constant-time operation. Because of the
42		* asynchronous nature of these maps, determining the current number
43		* of elements requires a traversal of the elements.  Additionally,
44	<	* the bulk operations <tt>putAll</tt>, <tt>equals</tt>, and
45	<	* <tt>clear</tt> are <em>not</em> guaranteed to be performed
44	>	* the bulk operations {@code putAll}, {@code equals}, and
45	>	* {@code clear} are <em>not</em> guaranteed to be performed
46		* atomically. For example, an iterator operating concurrently with a
47	<	* <tt>putAll</tt> operation might view only some of the added
47	>	* {@code putAll} operation might view only some of the added
48		* elements.
49		*
50		* <p>This class and its views and iterators implement all of the
51		* <em>optional</em> methods of the {@link Map} and {@link Iterator}
52		* interfaces. Like most other concurrent collections, this class does
53	<	* not permit the use of <tt>null</tt> keys or values because some
53	>	* not permit the use of {@code null} keys or values because some
54		* null return values cannot be reliably distinguished from the
55		* absence of elements.
56		*
#	Line 212 | Line 212 | public class ConcurrentSkipListMap<K,V>
212		* highly contended cases.
213		*
214		* Unlike most skip-list implementations, index insertion and
215	<	* deletion here require a separate traversal pass occuring after
215	>	* deletion here require a separate traversal pass occurring after
216		* the base-level action, to add or remove index nodes.  This adds
217		* to single-threaded overhead, but improves contended
218		* multithreaded performance by narrowing interference windows,
#	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		*/
#	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
421		* test if value points to node.
422	<	* @param n a possibly null reference to a node
422	>	*
423		* @return true if this node is a marker node
424		*/
425		boolean isMarker() {
#	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,
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.
471	>	* is deleted, else null
472		*/
473		V getValidValue() {
474		Object v = value;
#	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 507 | Line 507 | public class ConcurrentSkipListMap<K,V>
507		volatile Index<K,V> right;
508
509		/**
510	<	* Creates index node with given values
510	>	* Creates index node with given values.
511		*/
512		Index(Node<K,V> node, Index<K,V> down, Index<K,V> right) {
513		this.node = node;
#	Line 580 | Line 580 | public class ConcurrentSkipListMap<K,V>
580		/**
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.
583	>	* support the {@code Map.Entry.setValue} method.
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 {@code UnsupportedOperationException}.
619	>	* @throws UnsupportedOperationException always
620		*/
621		public V setValue(V value) {
622		throw new UnsupportedOperationException();
#	Line 644 | Line 644 | public class ConcurrentSkipListMap<K,V>
644
645		/**
646		* Returns a String consisting of the key followed by an
647	<	* equals sign (<tt>"="</tt>) followed by the associated
647	>	* equals sign ({@code "="}) 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 696 | Line 696 | public class ConcurrentSkipListMap<K,V>
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)
#	Line 720 | Line 720 | public class ConcurrentSkipListMap<K,V>
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) {
#	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.
#	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 807 | Line 807 | public class ConcurrentSkipListMap<K,V>
807		* were performed.
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 (;;) {
#	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		}
#	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 917 | Line 917 | public class ConcurrentSkipListMap<K,V>
917		* Main insertion method.  Adds element if not present, or
918		* replaces value if present and onlyIfAbsent is false.
919		* @param kkey the key
920	<	* @param value  the value that must be associated with 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
923		*/
#	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 987 | Line 987 | public class ConcurrentSkipListMap<K,V>
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 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
1045	>	* snapshotted by callers to provide correct insertion level.
1046		* @param indexLevel the level of the index
1047		*/
1048		private void addIndex(Index<K,V> idx, HeadIndex<K,V> h, int indexLevel) {
#	Line 1196 | Line 1196 | public class ConcurrentSkipListMap<K,V>
1196		}
1197
1198		/**
1199	<	* Version of remove with boolean return. Needed by view classes
1199	>	* Version of remove with boolean return. Needed by view classes.
1200		*/
1201		boolean removep(Object key) {
1202		return doRemove(key, null) != null;
#	Line 1221 | Line 1221 | public class ConcurrentSkipListMap<K,V>
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
#	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 1270 | Line 1270 | public class ConcurrentSkipListMap<K,V>
1270		}
1271		}
1272
1273	<	/**
1274	<	* Remove first entry; return key or null if empty.
1273	>	/**
1274	>	* Removes first entry; return key or null if empty.
1275		*/
1276		K pollFirstKey() {
1277		return (K)doRemoveFirst(true);
#	Line 1306 | Line 1306 | public class ConcurrentSkipListMap<K,V>
1306		Node<K,V> n = b.next;
1307		for (;;) {
1308		if (n == null)
1309	<	return (b.isBaseHeader())? null : b;
1309	>	return b.isBaseHeader() ? null : b;
1310		Node<K,V> f = n.next;            // inconsistent read
1311		if (n != b.next)
1312		break;
#	Line 1368 | Line 1368 | public class ConcurrentSkipListMap<K,V>
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 1405 | Line 1405 | public class ConcurrentSkipListMap<K,V>
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 1432 | Line 1432 | public class ConcurrentSkipListMap<K,V>
1432		Node<K,V> n = b.next;
1433		for (;;) {
1434		if (n == null)
1435	<	return ((rel & LT) == 0 || b.isBaseHeader())? null : b;
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 {@code null}.
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 {@code null}.
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
1494		* @param least minimum allowed key value
1495		* @param fence key greater than maximum allowed key value
1496		* @param keyOnly if true return key, else return SnapshotEntry
1497	<	* @return Key or Entry fitting relation, or <tt>null</tt> if no such
1497	>	* @return Key or Entry fitting relation, or {@code null} if no such
1498		*/
1499		Object getNear(K kkey, int rel, K least, K fence, boolean keyOnly) {
1500		K key = kkey;
#	Line 1513 | Line 1513 | public class ConcurrentSkipListMap<K,V>
1513		K k = n.key;
1514		V v = n.getValidValue();
1515		if (v != null)
1516	<	return keyOnly? k : new SnapshotEntry<K,V>(k, v);
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
1525	<	* @return least Key or Entry, or <tt>null</tt> if no such
1525	>	* @return least Key or Entry, or {@code null} if no such
1526		*/
1527		Object removeFirstEntryOfSubrange(K least, K fence, boolean keyOnly) {
1528		for (;;) {
#	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
1546	<	* @return least Key or Entry, or <tt>null</tt> if no such
1546	>	* @return least Key or Entry, or {@code null} if no such
1547		*/
1548		Object removeLastEntryOfSubrange(K least, K fence, boolean keyOnly) {
1549		for (;;) {
#	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 1574 | Line 1574 | public class ConcurrentSkipListMap<K,V>
1574		* Constructs a new empty map, sorted according to the given comparator.
1575		*
1576		* @param c the comparator that will be used to sort this map.  A
1577	<	*        <tt>null</tt> value indicates that the keys' <i>natural
1577	>	*        {@code null} value indicates that the keys' <i>natural
1578		*        ordering</i> should be used.
1579		*/
1580		public ConcurrentSkipListMap(Comparator<? super K> c) {
#	Line 1586 | Line 1586 | public class ConcurrentSkipListMap<K,V>
1586		* Constructs a new map containing the same mappings as the given map,
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 {@code null}
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	>	* {@code SortedMap}, 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.
1604	>	* map, and whose comparator is to be used to sort this map
1605		* @throws NullPointerException if the specified sorted map is
1606	<	* <tt>null</tt>.
1606	>	* {@code null}
1607		*/
1608		public ConcurrentSkipListMap(SortedMap<K, ? extends V> m) {
1609		this.comparator = m.comparator();
#	Line 1612 | Line 1612 | public class ConcurrentSkipListMap<K,V>
1612		}
1613
1614		/**
1615	<	* Returns a shallow copy of this <tt>Map</tt> instance. (The keys and
1615	>	* Returns a shallow copy of this {@code Map} 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 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 {@code Map} 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
1696	<	* <tt>null</tt>. The key-value mappings are emitted in key-order
1696	>	* {@code null}. 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).
1699		*/
#	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 {@code Map} instance from a stream.
1718		*/
1719		private void readObject(final java.io.ObjectInputStream s)
1720		throws java.io.IOException, ClassNotFoundException {
#	Line 1728 | Line 1728 | public class ConcurrentSkipListMap<K,V>
1728		* distinct because readObject calls can't be nicely adapted
1729		* as the kind of iterator needed by buildFromSorted. (They
1730		* can be, but doing so requires type cheats and/or creation
1731	<	* of adaptor classes.) It is simpler to just adapt the code.
1731	>	* of adapter classes.) It is simpler to just adapt the code.
1732		*/
1733
1734		HeadIndex<K,V> h = head;
#	Line 1777 | Line 1777 | public class ConcurrentSkipListMap<K,V>
1777		/* ------ Map API methods ------ */
1778
1779		/**
1780	<	* Returns <tt>true</tt> if this map contains a mapping for the specified
1780	>	* Returns {@code true} if this map contains a mapping for the specified
1781		* key.
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.
1782	>	* @param key key whose presence in this map is to be tested
1783	>	* @return {@code true} if this map contains a mapping for the
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 {@code null}
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	>	* {@code null} 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	>	*               {@code null} 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 {@code null}
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.
1816	>	* @return previous value associated with specified key, or {@code null}
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 {@code null}
1821		*/
1822		public V put(K key, V value) {
1823		if (value == null)
#	Line 1829 | Line 1829 | public class ConcurrentSkipListMap<K,V>
1829		* Removes the mapping for this key from this Map if present.
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.
1832	>	* @return previous value associated with specified key, or {@code null}
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 {@code null}
1838		*/
1839		public V remove(Object key) {
1840		return doRemove(key, null);
1841		}
1842
1843		/**
1844	<	* Returns <tt>true</tt> if this map maps one or more keys to the
1844	>	* Returns {@code true} if this map maps one or more keys to the
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.
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>.
1848	>	* @param value value whose presence in this Map is to be tested
1849	>	* @return  {@code true} if a mapping to {@code value} exists;
1850	>	*          {@code false} otherwise
1851	>	* @throws  NullPointerException  if the value is {@code null}
1852		*/
1853		public boolean containsValue(Object value) {
1854		if (value == null)
#	Line 1863 | Line 1863 | public class ConcurrentSkipListMap<K,V>
1863
1864		/**
1865		* Returns the number of elements in this map.  If this map
1866	<	* contains more than <tt>Integer.MAX_VALUE</tt> elements, it
1867	<	* returns <tt>Integer.MAX_VALUE</tt>.
1866	>	* contains more than {@code Integer.MAX_VALUE} elements, it
1867	>	* returns {@code Integer.MAX_VALUE}.
1868		*
1869		* <p>Beware that, unlike in most collections, this method is
1870		* <em>NOT</em> a constant-time operation. Because of the
#	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.
1890	>	* Returns {@code true} if this map contains no key-value mappings.
1891	>	* @return {@code true} if this map contains no key-value mappings
1892		*/
1893		public boolean isEmpty() {
1894		return findFirst() == null;
#	Line 1905 | Line 1905 | public class ConcurrentSkipListMap<K,V>
1905		* Returns a set view of the keys contained in this map.  The set is
1906		* backed by the map, so changes to the map are reflected in the set, and
1907		* vice-versa.  The set supports element removal, which removes the
1908	<	* corresponding mapping from this map, via the <tt>Iterator.remove</tt>,
1909	<	* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and
1910	<	* <tt>clear</tt> operations.  It does not support the <tt>add</tt> or
1911	<	* <tt>addAll</tt> operations.
1912	<	* The view's <tt>iterator</tt> is a "weakly consistent" iterator that
1908	>	* corresponding mapping from this map, via the {@code Iterator.remove},
1909	>	* {@code Set.remove}, {@code removeAll}, {@code retainAll}, and
1910	>	* {@code clear} operations.  It does not support the {@code add} or
1911	>	* {@code addAll} operations.
1912	>	* The view's {@code iterator} is a "weakly consistent" iterator that
1913		* will never throw {@link java.util.ConcurrentModificationException},
1914		* and guarantees to traverse elements as they existed upon
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 1936 | Line 1936 | public class ConcurrentSkipListMap<K,V>
1936		* descending order.  The set is backed by the map, so changes to
1937		* the map are reflected in the set, and vice-versa.  The set
1938		* supports element removal, which removes the corresponding
1939	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
1940	<	* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>,
1941	<	* and <tt>clear</tt> operations.  It does not support the
1942	<	* <tt>add</tt> or <tt>addAll</tt> operations.  The view's
1943	<	* <tt>iterator</tt> is a "weakly consistent" iterator that will
1939	>	* mapping from this map, via the {@code Iterator.remove},
1940	>	* {@code Set.remove}, {@code removeAll}, {@code retainAll},
1941	>	* and {@code clear} operations.  It does not support the
1942	>	* {@code add} or {@code addAll} operations.  The view's
1943	>	* {@code iterator} is a "weakly consistent" iterator that will
1944		* never throw {@link java.util.ConcurrentModificationException},
1945		* and guarantees to traverse elements as they existed upon
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 1967 | Line 1967 | public class ConcurrentSkipListMap<K,V>
1967		* The collection is backed by the map, so changes to the map are
1968		* reflected in the collection, and vice-versa.  The collection
1969		* supports element removal, which removes the corresponding
1970	<	* mapping from this map, via the <tt>Iterator.remove</tt>,
1971	<	* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
1972	<	* <tt>retainAll</tt>, and <tt>clear</tt> operations.  It does not
1973	<	* support the <tt>add</tt> or <tt>addAll</tt> operations.  The
1974	<	* view's <tt>iterator</tt> is a "weakly consistent" iterator that
1970	>	* mapping from this map, via the {@code Iterator.remove},
1971	>	* {@code Collection.remove}, {@code removeAll},
1972	>	* {@code retainAll}, and {@code clear} operations.  It does not
1973	>	* support the {@code add} or {@code addAll} operations.  The
1974	>	* view's {@code iterator} is a "weakly consistent" iterator that
1975		* will never throw {@link
1976		* java.util.ConcurrentModificationException}, and guarantees to
1977		* traverse elements as they existed upon construction of the
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 1988 | Line 1988 | public class ConcurrentSkipListMap<K,V>
1988		/**
1989		* Returns a collection view of the mappings contained in this
1990		* map.  Each element in the returned collection is a
1991	<	* <tt>Map.Entry</tt>.  The collection is backed by the map, so
1991	>	* {@code Map.Entry}.  The collection is backed by the map, so
1992		* changes to the map are reflected in the collection, and
1993		* vice-versa.  The collection supports element removal, which
1994		* removes the corresponding mapping from the map, via the
1995	<	* <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
1996	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
1997	<	* operations.  It does not support the <tt>add</tt> or
1998	<	* <tt>addAll</tt> operations.  The view's <tt>iterator</tt> is a
1995	>	* {@code Iterator.remove}, {@code Collection.remove},
1996	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
1997	>	* operations.  It does not support the {@code add} or
1998	>	* {@code addAll} operations.  The view's {@code iterator} is a
1999		* "weakly consistent" iterator that will never throw {@link
2000		* java.util.ConcurrentModificationException}, and guarantees to
2001		* traverse elements as they existed upon construction of the
2002		* iterator, and may (but is not guaranteed to) reflect any
2003		* modifications subsequent to construction. The
2004	<	* <tt>Map.Entry</tt> elements returned by
2005	<	* <tt>iterator.next()</tt> do <em>not</em> support the
2006	<	* <tt>setValue</tt> operation.
2004	>	* {@code Map.Entry} elements returned by
2005	>	* {@code iterator.next()} do <em>not</em> support the
2006	>	* {@code setValue} 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 2015 | Line 2015 | public class ConcurrentSkipListMap<K,V>
2015		/**
2016		* Returns a collection view of the mappings contained in this
2017		* map, in descending order.  Each element in the returned
2018	<	* collection is a <tt>Map.Entry</tt>.  The collection is backed
2018	>	* collection is a {@code Map.Entry}.  The collection is backed
2019		* by the map, so changes to the map are reflected in the
2020		* collection, and vice-versa.  The collection supports element
2021		* removal, which removes the corresponding mapping from the map,
2022	<	* via the <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>,
2023	<	* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
2024	<	* operations.  It does not support the <tt>add</tt> or
2025	<	* <tt>addAll</tt> operations.  The view's <tt>iterator</tt> is a
2022	>	* via the {@code Iterator.remove}, {@code Collection.remove},
2023	>	* {@code removeAll}, {@code retainAll}, and {@code clear}
2024	>	* operations.  It does not support the {@code add} or
2025	>	* {@code addAll} operations.  The view's {@code iterator} is a
2026		* "weakly consistent" iterator that will never throw {@link
2027		* java.util.ConcurrentModificationException}, and guarantees to
2028		* traverse elements as they existed upon construction of the
2029		* iterator, and may (but is not guaranteed to) reflect any
2030		* modifications subsequent to construction. The
2031	<	* <tt>Map.Entry</tt> elements returned by
2032	<	* <tt>iterator.next()</tt> do <em>not</em> support the
2033	<	* <tt>setValue</tt> operation.
2031	>	* {@code Map.Entry} elements returned by
2032	>	* {@code iterator.next()} do <em>not</em> support the
2033	>	* {@code setValue} 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 2043 | Line 2043 | public class ConcurrentSkipListMap<K,V>
2043
2044		/**
2045		* Compares the specified object with this map for equality.
2046	<	* Returns <tt>true</tt> if the given object is also a map and the
2046	>	* Returns {@code true} if the given object is also a map and the
2047		* two maps represent the same mappings.  More formally, two maps
2048	<	* <tt>t1</tt> and <tt>t2</tt> represent the same mappings if
2049	<	* <tt>t1.keySet().equals(t2.keySet())</tt> and for every key
2050	<	* <tt>k</tt> in <tt>t1.keySet()</tt>, <tt> (t1.get(k)==null ?
2051	<	* t2.get(k)==null : t1.get(k).equals(t2.get(k))) </tt>.  This
2048	>	* {@code t1} and {@code t2} represent the same mappings if
2049	>	* {@code t1.keySet().equals(t2.keySet())} and for every key
2050	>	* {@code k} in {@code t1.keySet()}, {@code  (t1.get(k)==null ?
2051	>	* t2.get(k)==null : t1.get(k).equals(t2.get(k))) }.  This
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 {@code true} 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) &&
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 2094 | Line 2094 | public class ConcurrentSkipListMap<K,V>
2094		* This is equivalent to
2095		* <pre>
2096		*   if (!map.containsKey(key))
2097	<	*      return map.put(key, value);
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.
2104	<	* @return previous value associated with specified key, or <tt>null</tt>
2105	<	*         if there was no mapping for 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 {@code null}
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 {@code null}
2110		*/
2111		public V putIfAbsent(K key, V value) {
2112		if (value == null)
#	Line 2115 | Line 2115 | public class ConcurrentSkipListMap<K,V>
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>
2121		*  if ((map.containsKey(key) && map.get(key).equals(value)) {
#	Line 2124 | Line 2124 | public class ConcurrentSkipListMap<K,V>
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 {@code null}
2133		*/
2134		public boolean remove(Object key, Object value) {
2135		if (value == null)
#	Line 2138 | Line 2138 | public class ConcurrentSkipListMap<K,V>
2138		}
2139
2140		/**
2141	<	* Replace entry for key only if currently mapped to given value.
2141	>	* Replaces entry for key only if currently mapped to given value.
2142		* Acts as
2143		* <pre>
2144		*  if ((map.containsKey(key) && map.get(key).equals(oldValue)) {
#	Line 2147 | Line 2147 | public class ConcurrentSkipListMap<K,V>
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	>	* {@code null}
2158		*/
2159		public boolean replace(K key, V oldValue, V newValue) {
2160		if (oldValue == null || newValue == null)
#	Line 2175 | Line 2175 | public class ConcurrentSkipListMap<K,V>
2175		}
2176
2177		/**
2178	<	* Replace entry for key only if currently mapped to some value.
2178	>	* Replaces entry for key only if currently mapped to some value.
2179		* Acts as
2180		* <pre>
2181		*  if ((map.containsKey(key)) {
#	Line 2183 | Line 2183 | public class ConcurrentSkipListMap<K,V>
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.
2188	<	* @return previous value associated with specified key, or <tt>null</tt>
2189	<	*         if there was no mapping for 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 {@code null}
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 {@code null}
2193		*/
2194		public V replace(K key, V value) {
2195		if (value == null)
#	Line 2208 | Line 2208 | public class ConcurrentSkipListMap<K,V>
2208		/* ------ SortedMap API methods ------ */
2209
2210		/**
2211	<	* Returns the comparator used to order this map, or <tt>null</tt>
2211	>	* Returns the comparator used to order this map, or {@code null}
2212		* if this map uses its keys' natural order.
2213		*
2214		* @return the comparator associated with this map, or
2215	<	* <tt>null</tt> if it uses its keys' natural sort method.
2215	>	* {@code null} if it uses its keys' natural sort method
2216		*/
2217		public Comparator<? super K> comparator() {
2218		return comparator;
#	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() {
2228		Node<K,V> n = findFirst();
#	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 2246 | Line 2246 | public class ConcurrentSkipListMap<K,V>
2246
2247		/**
2248		* Returns a view of the portion of this map whose keys range from
2249	<	* <tt>fromKey</tt>, inclusive, to <tt>toKey</tt>, exclusive.  (If
2250	<	* <tt>fromKey</tt> and <tt>toKey</tt> are equal, the returned sorted map
2249	>	* {@code fromKey}, inclusive, to {@code toKey}, exclusive.  (If
2250	>	* {@code fromKey} and {@code toKey} 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	>	* {@code fromKey}, inclusive, to {@code toKey}, exclusive
2259		*
2260	<	* @throws ClassCastException if <tt>fromKey</tt> and <tt>toKey</tt>
2260	>	* @throws ClassCastException if {@code fromKey} and {@code toKey}
2261		*         cannot be compared to one another using this map's comparator
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>.
2265	<	* @throws NullPointerException if <tt>fromKey</tt> or <tt>toKey</tt> is
2266	<	*               <tt>null</tt>.
2262	>	*         (or, if the map has no comparator, using natural ordering)
2263	>	* @throws IllegalArgumentException if {@code fromKey} is greater than
2264	>	*         {@code toKey}
2265	>	* @throws NullPointerException if {@code fromKey} or {@code toKey} is
2266	>	*               {@code null}
2267		*/
2268		public ConcurrentNavigableMap<K,V> subMap(K fromKey, K toKey) {
2269		if (fromKey == null || toKey == null)
#	Line 2273 | Line 2273 | public class ConcurrentSkipListMap<K,V>
2273
2274		/**
2275		* Returns a view of the portion of this map whose keys are
2276	<	* strictly less than <tt>toKey</tt>.  The returned sorted map is
2276	>	* strictly less than {@code toKey}.  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 {@code toKey}
2282		*
2283	<	* @throws ClassCastException if <tt>toKey</tt> is not compatible
2283	>	* @throws ClassCastException if {@code toKey} 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 {@code toKey} does not implement {@code Comparable})
2286	>	* @throws NullPointerException if {@code toKey} is {@code null}
2287		*/
2288		public ConcurrentNavigableMap<K,V> headMap(K toKey) {
2289		if (toKey == null)
#	Line 2293 | Line 2293 | public class ConcurrentSkipListMap<K,V>
2293
2294		/**
2295		* Returns a view of the portion of this map whose keys are
2296	<	* greater than or equal to <tt>fromKey</tt>.  The returned sorted
2296	>	* greater than or equal to {@code fromKey}.  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>.
2302	<	* @throws ClassCastException if <tt>fromKey</tt> is not
2301	>	* greater than or equal to {@code fromKey}
2302	>	* @throws ClassCastException if {@code fromKey} 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>.
2304	>	* comparator, if {@code fromKey} does not implement
2305	>	* {@code Comparable})
2306	>	* @throws NullPointerException if {@code fromKey} is {@code null}
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 2315 | Line 2315 | public class ConcurrentSkipListMap<K,V>
2315
2316		/**
2317		* Returns a key-value mapping associated with the least key
2318	<	* greater than or equal to the given key, or <tt>null</tt> if
2318	>	* greater than or equal to the given key, or {@code null} if
2319		* there is no such entry. The returned entry does <em>not</em>
2320	<	* support the <tt>Entry.setValue</tt> method.
2320	>	* support the {@code Entry.setValue} method.
2321		*
2322	<	* @param key the key.
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	>	* {@code null} 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 {@code null}
2328		*/
2329		public Map.Entry<K,V> ceilingEntry(K key) {
2330		return getNear(key, GT|EQ);
#	Line 2332 | Line 2332 | public class ConcurrentSkipListMap<K,V>
2332
2333		/**
2334		* Returns least key greater than or equal to the given key, or
2335	<	* <tt>null</tt> if there is no such key.
2335	>	* {@code null} if there is no such key.
2336		*
2337	<	* @param key the key.
2338	<	* @return the ceiling key, or <tt>null</tt>
2339	<	* if there is no such key.
2337	>	* @param key the key
2338	>	* @return the ceiling key, or {@code null}
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 {@code null}
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		/**
2350		* Returns a key-value mapping associated with the greatest
2351	<	* key strictly less than the given key, or <tt>null</tt> if there is no
2351	>	* key strictly less than the given key, or {@code null} if there is no
2352		* such entry. The returned entry does <em>not</em> support
2353	<	* the <tt>Entry.setValue</tt> method.
2353	>	* the {@code Entry.setValue} method.
2354		*
2355	<	* @param key the key.
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 {@code null} 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 {@code null}
2361		*/
2362		public Map.Entry<K,V> lowerEntry(K key) {
2363		return getNear(key, LT);
#	Line 2365 | Line 2365 | public class ConcurrentSkipListMap<K,V>
2365
2366		/**
2367		* Returns the greatest key strictly less than the given key, or
2368	<	* <tt>null</tt> if there is no such key.
2368	>	* {@code null} if there is no such key.
2369		*
2370	<	* @param key the key.
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 {@code null} 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 {@code null}
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		/**
2383		* Returns a key-value mapping associated with the greatest key
2384	<	* less than or equal to the given key, or <tt>null</tt> if there
2384	>	* less than or equal to the given key, or {@code null} if there
2385		* is no such entry. The returned entry does <em>not</em> support
2386	<	* the <tt>Entry.setValue</tt> method.
2386	>	* the {@code Entry.setValue} method.
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.
2388	>	* @param key the key
2389	>	* @return an Entry associated with floor of given key, or {@code null}
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 {@code null}
2394		*/
2395		public Map.Entry<K,V> floorEntry(K key) {
2396		return getNear(key, LT|EQ);
#	Line 2398 | Line 2398 | public class ConcurrentSkipListMap<K,V>
2398
2399		/**
2400		* Returns the greatest key
2401	<	* less than or equal to the given key, or <tt>null</tt> if there
2401	>	* less than or equal to the given key, or {@code null} if there
2402		* is no such 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.
2404	>	* @param key the key
2405	>	* @return the floor of given key, or {@code null} if there is no
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 {@code null}
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		/**
2417		* Returns a key-value mapping associated with the least key
2418	<	* strictly greater than the given key, or <tt>null</tt> if there
2418	>	* strictly greater than the given key, or {@code null} if there
2419		* is no such entry. The returned entry does <em>not</em> support
2420	<	* the <tt>Entry.setValue</tt> method.
2420	>	* the {@code Entry.setValue} method.
2421		*
2422	<	* @param key the key.
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	>	* {@code null} 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 {@code null}
2428		*/
2429		public Map.Entry<K,V> higherEntry(K key) {
2430		return getNear(key, GT);
#	Line 2432 | Line 2432 | public class ConcurrentSkipListMap<K,V>
2432
2433		/**
2434		* Returns the least key strictly greater than the given key, or
2435	<	* <tt>null</tt> if there is no such key.
2435	>	* {@code null} if there is no such key.
2436		*
2437	<	* @param key the key.
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	>	* {@code null} 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 {@code null}
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		/**
2450		* Returns a key-value mapping associated with the least
2451	<	* key in this map, or <tt>null</tt> if the map is empty.
2451	>	* key in this map, or {@code null} if the map is empty.
2452		* The returned entry does <em>not</em> support
2453	<	* the <tt>Entry.setValue</tt> method.
2453	>	* the {@code Entry.setValue} method.
2454		*
2455	<	* @return an Entry with least key, or <tt>null</tt>
2456	<	* if the map is empty.
2455	>	* @return an Entry with least key, or {@code null}
2456	>	* if the map is empty
2457		*/
2458		public Map.Entry<K,V> firstEntry() {
2459		for (;;) {
#	Line 2468 | Line 2468 | public class ConcurrentSkipListMap<K,V>
2468
2469		/**
2470		* Returns a key-value mapping associated with the greatest
2471	<	* key in this map, or <tt>null</tt> if the map is empty.
2471	>	* key in this map, or {@code null} if the map is empty.
2472		* The returned entry does <em>not</em> support
2473	<	* the <tt>Entry.setValue</tt> method.
2473	>	* the {@code Entry.setValue} method.
2474		*
2475	<	* @return an Entry with greatest key, or <tt>null</tt>
2476	<	* if the map is empty.
2475	>	* @return an Entry with greatest key, or {@code null}
2476	>	* if the map is empty
2477		*/
2478		public Map.Entry<K,V> lastEntry() {
2479		for (;;) {
#	Line 2488 | Line 2488 | public class ConcurrentSkipListMap<K,V>
2488
2489		/**
2490		* Removes and returns a key-value mapping associated with
2491	<	* the least key in this map, or <tt>null</tt> if the map is empty.
2491	>	* the least key in this map, or {@code null} if the map is empty.
2492		* The returned entry does <em>not</em> support
2493	<	* the <tt>Entry.setValue</tt> method.
2493	>	* the {@code Entry.setValue} method.
2494		*
2495	<	* @return the removed first entry of this map, or <tt>null</tt>
2496	<	* if the map is empty.
2495	>	* @return the removed first entry of this map, or {@code null}
2496	>	* if the map is empty
2497		*/
2498		public Map.Entry<K,V> pollFirstEntry() {
2499		return (SnapshotEntry<K,V>)doRemoveFirst(false);
#	Line 2501 | Line 2501 | public class ConcurrentSkipListMap<K,V>
2501
2502		/**
2503		* Removes and returns a key-value mapping associated with
2504	<	* the greatest key in this map, or <tt>null</tt> if the map is empty.
2504	>	* the greatest key in this map, or {@code null} if the map is empty.
2505		* The returned entry does <em>not</em> support
2506	<	* the <tt>Entry.setValue</tt> method.
2506	>	* the {@code Entry.setValue} method.
2507		*
2508	<	* @return the removed last entry of this map, or <tt>null</tt>
2509	<	* if the map is empty.
2508	>	* @return the removed last entry of this map, or {@code null}
2509	>	* if the map is empty
2510		*/
2511		public Map.Entry<K,V> pollLastEntry() {
2512		return (SnapshotEntry<K,V>)doRemoveLast(false);
#	Line 2525 | Line 2525 | public class ConcurrentSkipListMap<K,V>
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
#	Line 2537 | Line 2537 | public class ConcurrentSkipListMap<K,V>
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 2548 | Line 2548 | public class ConcurrentSkipListMap<K,V>
2548
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>.
2551	>	* or first node if least is {@code null}, but not greater or
2552	>	* equal to fence, or end if fence is {@code null}.
2553		*/
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 2616 | Line 2616 | public class ConcurrentSkipListMap<K,V>
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>.
2619	>	* last node if fence is {@code null}, but not less than
2620	>	* least, or beginning if lest is {@code null}.
2621		*/
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 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
#	Line 2842 | Line 2842 | public class ConcurrentSkipListMap<K,V>
2842		}
2843
2844		final class DescendingEntryIterator extends EntryIter
2845	<	implements Iterator<Map.Entry<K,V>>  {
2845	>	implements Iterator<Map.Entry<K,V>> {
2846		DescendingEntryIterator() {
2847		initDescending();
2848		}
#	Line 2854 | Line 2854 | public class ConcurrentSkipListMap<K,V>
2854		}
2855
2856		final class DescendingSubMapEntryIterator extends EntryIter
2857	<	implements Iterator<Map.Entry<K,V>>  {
2857	>	implements Iterator<Map.Entry<K,V>> {
2858		final K least;
2859		DescendingSubMapEntryIterator(K least, K fence) {
2860		initDescending(least, fence);
#	Line 3025 | Line 3025 | public class ConcurrentSkipListMap<K,V>
3025		* underlying maps, differing in that mappings outside their range are
3026		* ignored, and attempts to add mappings outside their ranges result
3027		* in {@link IllegalArgumentException}.  Instances of this class are
3028	<	* constructed only using the <tt>subMap</tt>, <tt>headMap</tt>, and
3029	<	* <tt>tailMap</tt> methods of their underlying maps.
3028	>	* constructed only using the {@code subMap}, {@code headMap}, and
3029	>	* {@code tailMap} methods of their underlying maps.
3030		*/
3031		static class ConcurrentSkipListSubMap<K,V> extends AbstractMap<K,V>
3032		implements ConcurrentNavigableMap<K,V>, java.io.Serializable {
#	Line 3048 | Line 3048 | public class ConcurrentSkipListMap<K,V>
3048
3049		/**
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
3051	>	* @param least inclusive least value, or {@code null} if from start
3052	>	* @param fence exclusive upper bound, or {@code null} if to end
3053	>	* @throws IllegalArgumentException if least and fence non-null
3054		*  and least greater than fence
3055		*/
3056		ConcurrentSkipListSubMap(ConcurrentSkipListMap<K,V> map,
#	Line 3095 | Line 3095 | public class ConcurrentSkipListMap<K,V>
3095		}
3096
3097		/**
3098	<	* Returns underlying map. Needed by ConcurrentSkipListSet
3098	>	* Returns underlying map. Needed by ConcurrentSkipListSet.
3099		* @return the backing map
3100		*/
3101		ConcurrentSkipListMap<K,V> getMap() {
#	Line 3103 | Line 3103 | public class ConcurrentSkipListMap<K,V>
3103		}
3104
3105		/**
3106	<	* Returns least key. Needed by ConcurrentSkipListSet
3107	<	* @return least key or <tt>null</tt> if from start
3106	>	* Returns least key. Needed by ConcurrentSkipListSet.
3107	>	* @return least key, or {@code null} if from start
3108		*/
3109		K getLeast() {
3110		return least;
3111		}
3112
3113		/**
3114	<	* Returns fence key. Needed by ConcurrentSkipListSet
3115	<	* @return fence key or <tt>null</tt> of to end
3114	>	* Returns fence key. Needed by ConcurrentSkipListSet.
3115	>	* @return fence key, or {@code null} if to end
3116		*/
3117		K getFence() {
3118		return fence;
#	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() {
#	Line 3149 | Line 3149 | public class ConcurrentSkipListMap<K,V>
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 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 3252 | Line 3253 | public class ConcurrentSkipListMap<K,V>
3253
3254		public Map.Entry<K,V> ceilingEntry(K key) {
3255		return (SnapshotEntry<K,V>)
3256	<	m.getNear(key, m.GT|m.EQ, least, fence, false);
3256	>	m.getNear(key, GT|EQ, least, fence, false);
3257		}
3258
3259		public K ceilingKey(K key) {
3260		return (K)
3261	<	m.getNear(key, m.GT|m.EQ, least, fence, true);
3261	>	m.getNear(key, GT|EQ, least, fence, true);
3262		}
3263
3264		public Map.Entry<K,V> lowerEntry(K key) {
3265		return (SnapshotEntry<K,V>)
3266	<	m.getNear(key, m.LT, least, fence, false);
3266	>	m.getNear(key, LT, least, fence, false);
3267		}
3268
3269		public K lowerKey(K key) {
3270		return (K)
3271	<	m.getNear(key, m.LT, least, fence, true);
3271	>	m.getNear(key, LT, least, fence, true);
3272		}
3273
3274		public Map.Entry<K,V> floorEntry(K key) {
3275		return (SnapshotEntry<K,V>)
3276	<	m.getNear(key, m.LT|m.EQ, least, fence, false);
3276	>	m.getNear(key, LT|EQ, least, fence, false);
3277		}
3278
3279		public K floorKey(K key) {
3280		return (K)
3281	<	m.getNear(key, m.LT|m.EQ, least, fence, true);
3281	>	m.getNear(key, LT|EQ, least, fence, true);
3282		}
3283
3284
3285		public Map.Entry<K,V> higherEntry(K key) {
3286		return (SnapshotEntry<K,V>)
3287	<	m.getNear(key, m.GT, least, fence, false);
3287	>	m.getNear(key, GT, least, fence, false);
3288		}
3289
3290		public K higherKey(K key) {
3291		return (K)
3292	<	m.getNear(key, m.GT, least, fence, true);
3292	>	m.getNear(key, GT, least, fence, true);
3293		}
3294
3295		public Map.Entry<K,V> firstEntry() {

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