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root/jsr166/jsr166/src/main/java/util/TreeSet.java

Comparing jsr166/src/main/java/util/TreeSet.java (file contents):
Revision 1.1 by dl, Tue Dec 28 12:14:07 2004 UTC vs.
Revision 1.15 by jsr166, Thu May 19 07:47:49 2005 UTC

#	Line 1 | Line 1
1		/*
2		* %W% %E%
3		*
4	<	* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
4	>	* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
5		* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6		*/
7
8	<	package java.util;
8	>	package java.util;
9
10		/**
11	<	* This class implements the <tt>Set</tt> interface, backed by a
12	<	* <tt>TreeMap</tt> instance.  This class guarantees that the sorted set will
13	<	* be in ascending element order, sorted according to the <i>natural order</i>
14	<	* of the elements (see <tt>Comparable</tt>), or by the comparator provided at
15	<	* set creation time, depending on which constructor is used.<p>
11	>	* A {@link NavigableSet} implementation based on a {@link TreeMap}.
12	>	* The elements are ordered using their {@linkplain Comparable natural
13	>	* ordering}, or by a {@link Comparator} provided at set creation
14	>	* time, depending on which constructor is used.
15		*
16	<	* This implementation provides guaranteed log(n) time cost for the basic
17	<	* operations (<tt>add</tt>, <tt>remove</tt> and <tt>contains</tt>).<p>
16	>	* <p>This implementation provides guaranteed log(n) time cost for the basic
17	>	* operations (<tt>add</tt>, <tt>remove</tt> and <tt>contains</tt>).
18		*
19	<	* Note that the ordering maintained by a set (whether or not an explicit
19	>	* <p>Note that the ordering maintained by a set (whether or not an explicit
20		* comparator is provided) must be <i>consistent with equals</i> if it is to
21		* correctly implement the <tt>Set</tt> interface.  (See <tt>Comparable</tt>
22		* or <tt>Comparator</tt> for a precise definition of <i>consistent with
23		* equals</i>.)  This is so because the <tt>Set</tt> interface is defined in
24		* terms of the <tt>equals</tt> operation, but a <tt>TreeSet</tt> instance
25	<	* performs all key comparisons using its <tt>compareTo</tt> (or
26	<	* <tt>compare</tt>) method, so two keys that are deemed equal by this method
25	>	* performs all element comparisons using its <tt>compareTo</tt> (or
26	>	* <tt>compare</tt>) method, so two elements that are deemed equal by this method
27		* are, from the standpoint of the set, equal.  The behavior of a set
28		* <i>is</i> well-defined even if its ordering is inconsistent with equals; it
29	<	* just fails to obey the general contract of the <tt>Set</tt> interface.<p>
29	>	* just fails to obey the general contract of the <tt>Set</tt> interface.
30		*
31	<	* <b>Note that this implementation is not synchronized.</b> If multiple
31	>	* <p><b>Note that this implementation is not synchronized.</b> If multiple
32		* threads access a set concurrently, and at least one of the threads modifies
33		* the set, it <i>must</i> be synchronized externally.  This is typically
34		* accomplished by synchronizing on some object that naturally encapsulates
#	Line 37 | Line 36 | package java.util;
36		* <tt>Collections.synchronizedSet</tt> method.  This is best done at creation
37		* time, to prevent accidental unsynchronized access to the set: <pre>
38		*     SortedSet s = Collections.synchronizedSortedSet(new TreeSet(...));
39	<	* </pre><p>
39	>	* </pre>
40		*
41	<	* The Iterators returned by this class's <tt>iterator</tt> method are
41	>	* <p>The iterators returned by this class's <tt>iterator</tt> method are
42		* <i>fail-fast</i>: if the set is modified at any time after the iterator is
43		* created, in any way except through the iterator's own <tt>remove</tt>
44	<	* method, the iterator will throw a <tt>ConcurrentModificationException</tt>.
44	>	* method, the iterator will throw a {@link ConcurrentModificationException}.
45		* Thus, in the face of concurrent modification, the iterator fails quickly
46		* and cleanly, rather than risking arbitrary, non-deterministic behavior at
47		* an undetermined time in the future.
#	Line 53 | Line 52 | package java.util;
52		* throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
53		* Therefore, it would be wrong to write a program that depended on this
54		* exception for its correctness:   <i>the fail-fast behavior of iterators
55	<	* should be used only to detect bugs.</i><p>
55	>	* should be used only to detect bugs.</i>
56		*
57	<	* This class is a member of the
57	>	* <p>This class is a member of the
58		* <a href="{@docRoot}/../guide/collections/index.html">
59		* Java Collections Framework</a>.
60		*
61	+	* @param <E> the type of elements maintained by this set
62	+	*
63		* @author  Josh Bloch
64		* @version %I%, %G%
65		* @see     Collection
#	Line 81 | Line 82 | public class TreeSet<E>
82		private static final Object PRESENT = new Object();
83
84		/**
85	<	* Constructs a set backed by the specified sorted map.
85	>	* Constructs a set backed by the specified navigable map.
86		*/
87		private TreeSet(NavigableMap<E,Object> m) {
88		this.m = m;
89		}
90
91		/**
92	<	* Constructs a new, empty set, sorted according to the elements' natural
93	<	* order.  All elements inserted into the set must implement the
94	<	* <tt>Comparable</tt> interface.  Furthermore, all such elements must be
95	<	* <i>mutually comparable</i>: <tt>e1.compareTo(e2)</tt> must not throw a
92	>	* Constructs a new, empty tree set, sorted according to the
93	>	* natural ordering of its elements.  All elements inserted into
94	>	* the set must implement the {@link Comparable} interface.
95	>	* Furthermore, all such elements must be <i>mutually
96	>	* comparable</i>: <tt>e1.compareTo(e2)</tt> must not throw a
97		* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and
98	<	* <tt>e2</tt> in the set.  If the user attempts to add an element to the
99	<	* set that violates this constraint (for example, the user attempts to
100	<	* add a string element to a set whose elements are integers), the
101	<	* <tt>add(Object)</tt> call will throw a <tt>ClassCastException</tt>.
102	<	*
101	<	* @see Comparable
98	>	* <tt>e2</tt> in the set.  If the user attempts to add an element
99	>	* to the set that violates this constraint (for example, the user
100	>	* attempts to add a string element to a set whose elements are
101	>	* integers), the <tt>add(Object)</tt> call will throw a
102	>	* <tt>ClassCastException</tt>.
103		*/
104		public TreeSet() {
105		this(new TreeMap<E,Object>());
106		}
107
108		/**
109	<	* Constructs a new, empty set, sorted according to the specified
109	>	* Constructs a new, empty tree set, sorted according to the specified
110		* comparator.  All elements inserted into the set must be <i>mutually
111		* comparable</i> by the specified comparator: <tt>comparator.compare(e1,
112		* e2)</tt> must not throw a <tt>ClassCastException</tt> for any elements
#	Line 113 | Line 114 | public class TreeSet<E>
114		* an element to the set that violates this constraint, the
115		* <tt>add(Object)</tt> call will throw a <tt>ClassCastException</tt>.
116		*
117	<	* @param c the comparator that will be used to sort this set.  A
118	<	*        <tt>null</tt> value indicates that the elements' <i>natural
119	<	*        ordering</i> should be used.
117	>	* @param comparator the comparator that will be used to order this set.
118	>	*        If <tt>null</tt>, the {@linkplain Comparable natural
119	>	*        ordering} of the elements will be used.
120		*/
121	<	public TreeSet(Comparator<? super E> c) {
122	<	this(new TreeMap<E,Object>(c));
121	>	public TreeSet(Comparator<? super E> comparator) {
122	>	this(new TreeMap<E,Object>(comparator));
123		}
124
125		/**
126	<	* Constructs a new set containing the elements in the specified
127	<	* collection, sorted according to the elements' <i>natural order</i>.
128	<	* All keys inserted into the set must implement the <tt>Comparable</tt>
129	<	* interface.  Furthermore, all such keys must be <i>mutually
130	<	* comparable</i>: <tt>k1.compareTo(k2)</tt> must not throw a
131	<	* <tt>ClassCastException</tt> for any elements <tt>k1</tt> and
132	<	* <tt>k2</tt> in the set.
132	<	*
133	<	* @param c The elements that will comprise the new set.
126	>	* Constructs a new tree set containing the elements in the specified
127	>	* collection, sorted according to the <i>natural ordering</i> of its
128	>	* elements.  All elements inserted into the set must implement the
129	>	* {@link Comparable} interface.  Furthermore, all such elements must be
130	>	* <i>mutually comparable</i>: <tt>e1.compareTo(e2)</tt> must not throw a
131	>	* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and
132	>	* <tt>e2</tt> in the set.
133		*
134	<	* @throws ClassCastException if the keys in the specified collection are
135	<	*         not comparable, or are not mutually comparable.
136	<	* @throws NullPointerException if the specified collection is null.
134	>	* @param c collection whose elements will comprise the new set
135	>	* @throws ClassCastException if the elements in <tt>c</tt> are
136	>	*         not {@link Comparable}, or are not mutually comparable
137	>	* @throws NullPointerException if the specified collection is null
138		*/
139		public TreeSet(Collection<? extends E> c) {
140		this();
#	Line 142 | Line 142 | public class TreeSet<E>
142		}
143
144		/**
145	<	* Constructs a new set containing the same elements as the specified
146	<	* sorted set, sorted according to the same ordering.
145	>	* Constructs a new tree set containing the same elements and
146	>	* using the same ordering as the specified sorted set.
147		*
148	<	* @param s sorted set whose elements will comprise the new set.
149	<	* @throws NullPointerException if the specified sorted set is null.
148	>	* @param s sorted set whose elements will comprise the new set
149	>	* @throws NullPointerException if the specified sorted set is null
150		*/
151		public TreeSet(SortedSet<E> s) {
152		this(s.comparator());
#	Line 154 | Line 154 | public class TreeSet<E>
154		}
155
156		/**
157	<	* Returns an iterator over the elements in this set.  The elements
158	<	* are returned in ascending order.
157	>	* Returns an iterator over the elements in this set in ascending order.
158		*
159	<	* @return an iterator over the elements in this set.
159	>	* @return an iterator over the elements in this set in ascending order
160		*/
161		public Iterator<E> iterator() {
162	<	return m.keySet().iterator();
162	>	return m.keySet().iterator();
163		}
164
165		/**
166	<	* Returns an iterator over the elements in this set.  The elements
168	<	* are returned in descending order.
166	>	* Returns an iterator over the elements in this set in descending order.
167		*
168	<	* @return an iterator over the elements in this set.
168	>	* @return an iterator over the elements in this set in descending order
169		*/
170		public Iterator<E> descendingIterator() {
171		return m.descendingKeySet().iterator();
#	Line 176 | Line 174 | public class TreeSet<E>
174		/**
175		* Returns the number of elements in this set (its cardinality).
176		*
177	<	* @return the number of elements in this set (its cardinality).
177	>	* @return the number of elements in this set (its cardinality)
178		*/
179		public int size() {
180		return m.size();
#	Line 185 | Line 183 | public class TreeSet<E>
183		/**
184		* Returns <tt>true</tt> if this set contains no elements.
185		*
186	<	* @return <tt>true</tt> if this set contains no elements.
186	>	* @return <tt>true</tt> if this set contains no elements
187		*/
188		public boolean isEmpty() {
189		return m.isEmpty();
#	Line 194 | Line 192 | public class TreeSet<E>
192		/**
193		* Returns <tt>true</tt> if this set contains the specified element.
194		*
195	<	* @param o the object to be checked for containment in this set.
196	<	* @return <tt>true</tt> if this set contains the specified element.
199	<	*
195	>	* @param o the object to be checked for containment in this set
196	>	* @return <tt>true</tt> if this set contains the specified element
197		* @throws ClassCastException if the specified object cannot be compared
198	<	*            with the elements currently in the set.
199	<	* @throws NullPointerException o is <tt>null</tt> and this map
200	<	* uses natural ordering and is non-empty, or its comparator does
201	<	* not tolerate <tt>null</tt> keys.
198	>	*         with the elements currently in the set
199	>	* @throws NullPointerException if the specified element is null
200	>	*         and this set uses natural ordering, or its comparator
201	>	*         does not permit null elements
202		*/
203		public boolean contains(Object o) {
204		return m.containsKey(o);
#	Line 210 | Line 207 | public class TreeSet<E>
207		/**
208		* Adds the specified element to this set if it is not already present.
209		*
210	<	* @param o element to be added to this set.
210	>	* @param e element to be added to this set
211		* @return <tt>true</tt> if the set did not already contain the specified
212	<	*         element.
216	<	*
212	>	*         element
213		* @throws ClassCastException if the specified object cannot be compared
214	<	*            with the elements currently in the set.
215	<	* @throws NullPointerException o is <tt>null</tt> and this map
216	<	* uses natural ordering and is non-empty, or its comparator does
217	<	* not tolerate <tt>null</tt> keys.
214	>	*         with the elements currently in the set
215	>	* @throws NullPointerException if the specified element is null
216	>	*         and this set uses natural ordering, or its comparator
217	>	*         does not permit null elements
218		*/
219	<	public boolean add(E o) {
220	<	return m.put(o, PRESENT)==null;
219	>	public boolean add(E e) {
220	>	return m.put(e, PRESENT)==null;
221		}
222
223		/**
224		* Removes the specified element from this set if it is present.
225		*
226	<	* @param o object to be removed from this set, if present.
227	<	* @return <tt>true</tt> if the set contained the specified element.
232	<	*
226	>	* @param o object to be removed from this set, if present
227	>	* @return <tt>true</tt> if the set contained the specified element
228		* @throws ClassCastException if the specified object cannot be compared
229	<	*            with the elements currently in the set.
230	<	* @throws NullPointerException o is <tt>null</tt> and this map
231	<	* uses natural ordering and is non-empty, or its comparator does
232	<	* not tolerate <tt>null</tt> keys.
229	>	*         with the elements currently in the set
230	>	* @throws NullPointerException if the specified element is null
231	>	*         and this set uses natural ordering, or its comparator
232	>	*         does not permit null elements
233		*/
234		public boolean remove(Object o) {
235		return m.remove(o)==PRESENT;
#	Line 242 | Line 237 | public class TreeSet<E>
237
238		/**
239		* Removes all of the elements from this set.
240	+	* The set will be empty after this call returns.
241		*/
242		public void clear() {
243		m.clear();
#	Line 250 | Line 246 | public class TreeSet<E>
246		/**
247		* Adds all of the elements in the specified collection to this set.
248		*
249	<	* @param c elements to be added
250	<	* @return <tt>true</tt> if this set changed as a result of the call.
255	<	*
249	>	* @param c collection containing elements to be added to this set
250	>	* @return <tt>true</tt> if this set changed as a result of the call
251		* @throws ClassCastException if the elements provided cannot be compared
252	<	*            with the elements currently in the set.
253	<	* @throws NullPointerException of the specified collection is
254	<	* <tt>null</tt> or if any element is <tt>null</tt> and this map
255	<	* uses natural ordering, or its comparator does not tolerate
261	<	* <tt>null</tt> keys.
252	>	*         with the elements currently in the set
253	>	* @throws NullPointerException if the specified collection is null or
254	>	*         if any element is null and this set uses natural ordering, or
255	>	*         its comparator does not permit null elements
256		*/
257		public  boolean addAll(Collection<? extends E> c) {
258		// Use linear-time version if applicable
259		if (m.size()==0 && c.size() > 0 &&
260		c instanceof SortedSet &&
261		m instanceof TreeMap) {
262	<	SortedSet<Map.Entry<E, Object>> set = (SortedSet<Map.Entry<E, Object>>) (SortedSet) c;
262	>	SortedSet<? extends E> set = (SortedSet<? extends E>) c;
263		TreeMap<E,Object> map = (TreeMap<E, Object>) m;
264	<	Comparator<? super E> cc = (Comparator<E>) set.comparator();
264	>	Comparator<? super E> cc = (Comparator<? super E>) set.comparator();
265		Comparator<? super E> mc = map.comparator();
266		if (cc==mc || (cc != null && cc.equals(mc))) {
267		map.addAllForTreeSet(set, PRESENT);
#	Line 278 | Line 272 | public class TreeSet<E>
272		}
273
274		/**
275	<	* Returns a view of the portion of this set whose elements range from
282	<	* <tt>fromElement</tt>, inclusive, to <tt>toElement</tt>, exclusive.  (If
283	<	* <tt>fromElement</tt> and <tt>toElement</tt> are equal, the returned
284	<	* sorted set is empty.)  The returned sorted set is backed by this set,
285	<	* so changes in the returned sorted set are reflected in this set, and
286	<	* vice-versa.  The returned sorted set supports all optional Set
287	<	* operations.<p>
288	<	*
289	<	* The sorted set returned by this method will throw an
290	<	* <tt>IllegalArgumentException</tt> if the user attempts to insert an
291	<	* element outside the specified range.<p>
292	<	*
293	<	* Note: this method always returns a <i>half-open range</i> (which
294	<	* includes its low endpoint but not its high endpoint).  If you need a
295	<	* <i>closed range</i> (which includes both endpoints), and the element
296	<	* type allows for calculation of the successor of a specified value,
297	<	* merely request the subrange from <tt>lowEndpoint</tt> to
298	<	* <tt>successor(highEndpoint)</tt>.  For example, suppose that <tt>s</tt>
299	<	* is a sorted set of strings.  The following idiom obtains a view
300	<	* containing all of the strings in <tt>s</tt> from <tt>low</tt> to
301	<	* <tt>high</tt>, inclusive: <pre>
302	<	*     NavigableSet sub = s.subSet(low, high+"\0");
303	<	* </pre>
304	<	*
305	<	* A similar technique can be used to generate an <i>open range</i> (which
306	<	* contains neither endpoint).  The following idiom obtains a view
307	<	* containing all of the strings in <tt>s</tt> from <tt>low</tt> to
308	<	* <tt>high</tt>, exclusive: <pre>
309	<	*     NavigableSet sub = s.subSet(low+"\0", high);
310	<	* </pre>
311	<	*
312	<	* @param fromElement low endpoint (inclusive) of the subSet.
313	<	* @param toElement high endpoint (exclusive) of the subSet.
314	<	* @return a view of the portion of this set whose elements range from
315	<	*         <tt>fromElement</tt>, inclusive, to <tt>toElement</tt>,
316	<	*         exclusive.
317	<	* @throws ClassCastException if <tt>fromElement</tt> and
318	<	*         <tt>toElement</tt> cannot be compared to one another using
319	<	*         this set's comparator (or, if the set has no comparator,
320	<	*         using natural ordering).
321	<	* @throws IllegalArgumentException if <tt>fromElement</tt> is greater than
322	<	*         <tt>toElement</tt>.
275	>	* @throws ClassCastException {@inheritDoc}
276		* @throws NullPointerException if <tt>fromElement</tt> or
277	<	*         <tt>toElement</tt> is <tt>null</tt> and this set uses natural
278	<	*         order, or its comparator does not tolerate <tt>null</tt>
279	<	*         elements.
280	<	*/
281	<	public NavigableSet<E> subSet(E fromElement, E toElement) {
282	<	return new TreeSet<E>(m.subMap(fromElement, toElement));
283	<	}
284	<
285	<	/**
286	<	* Returns a view of the portion of this set whose elements are strictly
287	<	* less than <tt>toElement</tt>.  The returned sorted set is backed by
288	<	* this set, so changes in the returned sorted set are reflected in this
289	<	* set, and vice-versa.  The returned sorted set supports all optional set
290	<	* operations.<p>
291	<	*
292	<	* The sorted set returned by this method will throw an
293	<	* <tt>IllegalArgumentException</tt> if the user attempts to insert an
294	<	* element greater than or equal to <tt>toElement</tt>.<p>
295	<	*
296	<	* Note: this method always returns a view that does not contain its
297	<	* (high) endpoint.  If you need a view that does contain this endpoint,
298	<	* and the element type allows for calculation of the successor of a
299	<	* specified value, merely request a headSet bounded by
300	<	* <tt>successor(highEndpoint)</tt>.  For example, suppose that <tt>s</tt>
301	<	* is a sorted set of strings.  The following idiom obtains a view
302	<	* containing all of the strings in <tt>s</tt> that are less than or equal
303	<	* to <tt>high</tt>: <pre> NavigableSet head = s.headSet(high+"\0");</pre>
304	<	*
352	<	* @param toElement high endpoint (exclusive) of the headSet.
353	<	* @return a view of the portion of this set whose elements are strictly
354	<	*         less than toElement.
355	<	* @throws ClassCastException if <tt>toElement</tt> is not compatible
356	<	*         with this set's comparator (or, if the set has no comparator,
357	<	*         if <tt>toElement</tt> does not implement <tt>Comparable</tt>).
358	<	* @throws IllegalArgumentException if this set is itself a subSet,
359	<	*         headSet, or tailSet, and <tt>toElement</tt> is not within the
360	<	*         specified range of the subSet, headSet, or tailSet.
361	<	* @throws NullPointerException if <tt>toElement</tt> is <tt>null</tt> and
362	<	*         this set uses natural ordering, or its comparator does
363	<	*         not tolerate <tt>null</tt> elements.
364	<	*/
365	<	public NavigableSet<E> headSet(E toElement) {
366	<	return new TreeSet<E>(m.headMap(toElement));
367	<	}
368	<
369	<	/**
370	<	* Returns a view of the portion of this set whose elements are
371	<	* greater than or equal to <tt>fromElement</tt>.  The returned sorted set
372	<	* is backed by this set, so changes in the returned sorted set are
373	<	* reflected in this set, and vice-versa.  The returned sorted set
374	<	* supports all optional set operations.<p>
375	<	*
376	<	* The sorted set returned by this method will throw an
377	<	* <tt>IllegalArgumentException</tt> if the user attempts to insert an
378	<	* element less than <tt>fromElement</tt>.
379	<	*
380	<	* Note: this method always returns a view that contains its (low)
381	<	* endpoint.  If you need a view that does not contain this endpoint, and
382	<	* the element type allows for calculation of the successor of a specified
383	<	* value, merely request a tailSet bounded by
384	<	* <tt>successor(lowEndpoint)</tt>.  For example, suppose that <tt>s</tt>
385	<	* is a sorted set of strings.  The following idiom obtains a view
386	<	* containing all of the strings in <tt>s</tt> that are strictly greater
387	<	* than <tt>low</tt>: <pre>
388	<	*     NavigableSet tail = s.tailSet(low+"\0");
389	<	* </pre>
390	<	*
391	<	* @param fromElement low endpoint (inclusive) of the tailSet.
392	<	* @return a view of the portion of this set whose elements are
393	<	*         greater than or equal to <tt>fromElement</tt>.
394	<	* @throws ClassCastException if <tt>fromElement</tt> is not compatible
395	<	*         with this set's comparator (or, if the set has no comparator,
396	<	*         if <tt>fromElement</tt> does not implement <tt>Comparable</tt>).
397	<	* @throws IllegalArgumentException if this set is itself a subSet,
398	<	*         headSet, or tailSet, and <tt>fromElement</tt> is not within the
399	<	*         specified range of the subSet, headSet, or tailSet.
400	<	* @throws NullPointerException if <tt>fromElement</tt> is <tt>null</tt>
401	<	*         and this set uses natural ordering, or its comparator does
402	<	*         not tolerate <tt>null</tt> elements.
403	<	*/
404	<	public NavigableSet<E> tailSet(E fromElement) {
405	<	return new TreeSet<E>(m.tailMap(fromElement));
277	>	*         <tt>toElement</tt> is null and this set uses natural ordering,
278	>	*         or its comparator does not permit null elements
279	>	* @throws IllegalArgumentException {@inheritDoc}
280	>	*/
281	>	public NavigableSet<E> navigableSubSet(E fromElement, E toElement) {
282	>	return new TreeSet<E>(m.navigableSubMap(fromElement, toElement));
283	>	}
284	>
285	>	/**
286	>	* @throws ClassCastException {@inheritDoc}
287	>	* @throws NullPointerException if <tt>toElement</tt> is null and
288	>	*         this set uses natural ordering, or its comparator does
289	>	*         not permit null elements
290	>	* @throws IllegalArgumentException {@inheritDoc}
291	>	*/
292	>	public NavigableSet<E> navigableHeadSet(E toElement) {
293	>	return new TreeSet<E>(m.navigableHeadMap(toElement));
294	>	}
295	>
296	>	/**
297	>	* @throws ClassCastException {@inheritDoc}
298	>	* @throws NullPointerException if <tt>fromElement</tt> is null and
299	>	*         this set uses natural ordering, or its comparator does
300	>	*         not permit null elements
301	>	* @throws IllegalArgumentException {@inheritDoc}
302	>	*/
303	>	public NavigableSet<E> navigableTailSet(E fromElement) {
304	>	return new TreeSet<E>(m.navigableTailMap(fromElement));
305		}
306
307		/**
308	<	* Returns the comparator used to order this sorted set, or <tt>null</tt>
309	<	* if this tree set uses its elements natural ordering.
308	>	* Equivalent to {@link #navigableSubSet} but with a return type
309	>	* conforming to the <tt>SortedSet</tt> interface.
310		*
311	<	* @return the comparator used to order this sorted set, or <tt>null</tt>
312	<	* if this tree set uses its elements natural ordering.
311	>	* <p>{@inheritDoc}
312	>	*
313	>	* @throws ClassCastException {@inheritDoc}
314	>	* @throws NullPointerException if <tt>fromElement</tt> or
315	>	*         <tt>toElement</tt> is null and this set uses natural ordering,
316	>	*         or its comparator does not permit null elements
317	>	* @throws IllegalArgumentException {@inheritDoc}
318		*/
319	+	public SortedSet<E> subSet(E fromElement, E toElement) {
320	+	return new TreeSet<E>(m.navigableSubMap(fromElement, toElement));
321	+	}
322	+
323	+	/**
324	+	* Equivalent to {@link #navigableHeadSet} but with a return type
325	+	* conforming to the <tt>SortedSet</tt> interface.
326	+	*
327	+	* <p>{@inheritDoc}
328	+	*
329	+	* @throws ClassCastException {@inheritDoc}
330	+	* @throws NullPointerException if <tt>toElement</tt> is null
331	+	*         and this set uses natural ordering, or its comparator does
332	+	*         not permit null elements
333	+	* @throws IllegalArgumentException {@inheritDoc}
334	+	*/
335	+	public SortedSet<E> headSet(E toElement) {
336	+	return new TreeSet<E>(m.navigableHeadMap(toElement));
337	+	}
338	+
339	+	/**
340	+	* Equivalent to {@link #navigableTailSet} but with a return type
341	+	* conforming to the <tt>SortedSet</tt> interface.
342	+	*
343	+	* <p>{@inheritDoc}
344	+	*
345	+	* @throws ClassCastException {@inheritDoc}
346	+	* @throws NullPointerException if <tt>fromElement</tt> is null
347	+	*         and this set uses natural ordering, or its comparator does
348	+	*         not permit null elements
349	+	* @throws IllegalArgumentException {@inheritDoc}
350	+	*/
351	+	public SortedSet<E> tailSet(E fromElement) {
352	+	return new TreeSet<E>(m.navigableTailMap(fromElement));
353	+	}
354	+
355		public Comparator<? super E> comparator() {
356		return m.comparator();
357		}
358
359		/**
360	<	* Returns the first (lowest) element currently in this sorted set.
421	<	*
422	<	* @return the first (lowest) element currently in this sorted set.
423	<	* @throws    NoSuchElementException sorted set is empty.
360	>	* @throws NoSuchElementException {@inheritDoc}
361		*/
362		public E first() {
363		return m.firstKey();
364		}
365
366		/**
367	<	* Returns the last (highest) element currently in this sorted set.
431	<	*
432	<	* @return the last (highest) element currently in this sorted set.
433	<	* @throws    NoSuchElementException sorted set is empty.
367	>	* @throws NoSuchElementException {@inheritDoc}
368		*/
369		public E last() {
370		return m.lastKey();
#	Line 438 | Line 372 | public class TreeSet<E>
372
373		// NavigableSet API methods
374
375	+	/**
376	+	* @throws ClassCastException {@inheritDoc}
377	+	* @throws NullPointerException if the specified element is null
378	+	*         and this set uses natural ordering, or its comparator
379	+	*         does not permit null elements
380	+	*/
381	+	public E lower(E e) {
382	+	return m.lowerKey(e);
383	+	}
384
385		/**
386	<	* Returns an element greater than or equal to the given element, or
387	<	* <tt>null</tt> if there is no such element.
388	<	*
389	<	* @param o the value to match
447	<	* @return an element greater than or equal to given element, or
448	<	* <tt>null</tt> if there is no such element.
449	<	* @throws ClassCastException if o cannot be compared with the elements
450	<	*            currently in the set.
451	<	* @throws NullPointerException o is <tt>null</tt> and this map
452	<	* uses natural ordering and is non-empty, or its comparator does
453	<	* not tolerate <tt>null</tt> keys.
454	<	*/
455	<	public E ceiling(E o) {
456	<	return m.ceilingKey(o);
457	<	}
458	<
459	<	/**
460	<	* Returns an element strictly less than the given element, or
461	<	* <tt>null</tt> if there is no such element.
462	<	*
463	<	* @param o the value to match
464	<	* @return the greatest element less than the given element, or
465	<	* <tt>null</tt> if there is no such element.
466	<	* @throws ClassCastException if o cannot be compared with the elements
467	<	*            currently in the set.
468	<	* @throws NullPointerException o is <tt>null</tt> and this map
469	<	* uses natural ordering and is non-empty, or its comparator does
470	<	* not tolerate <tt>null</tt> keys.
471	<	*/
472	<	public E lower(E o) {
473	<	return m.lowerKey(o);
474	<	}
475	<
476	<	/**
477	<	* Returns an element less than or equal to the given element, or
478	<	* <tt>null</tt> if there is no such element.
479	<	*
480	<	* @param o the value to match
481	<	* @return the greatest element less than or equal to given
482	<	* element, or <tt>null</tt> if there is no such element.
483	<	* @throws ClassCastException if o cannot be compared with the elements
484	<	*            currently in the set.
485	<	* @throws NullPointerException o is <tt>null</tt> and this map
486	<	* uses natural ordering and is non-empty, or its comparator does
487	<	* not tolerate <tt>null</tt> keys.
488	<	*/
489	<	public E floor(E o) {
490	<	return m.floorKey(o);
491	<	}
492	<
493	<	/**
494	<	* Returns an element strictly greater than the given element, or
495	<	* <tt>null</tt> if there is no such element.
496	<	*
497	<	* @param o the value to match
498	<	* @return the least element greater than the given element, or
499	<	* <tt>null</tt> if there is no such element.
500	<	* @throws ClassCastException if o cannot be compared with the elements
501	<	*            currently in the set.
502	<	* @throws NullPointerException o is <tt>null</tt> and this map
503	<	* uses natural ordering and is non-empty, or its comparator does
504	<	* not tolerate <tt>null</tt> keys.
386	>	* @throws ClassCastException {@inheritDoc}
387	>	* @throws NullPointerException if the specified element is null
388	>	*         and this set uses natural ordering, or its comparator
389	>	*         does not permit null elements
390		*/
391	<	public E higher(E o) {
392	<	return m.higherKey(o);
391	>	public E floor(E e) {
392	>	return m.floorKey(e);
393		}
394
395		/**
396	<	* Retrieves and removes the first (lowest) element.
397	<	*
398	<	* @return the least element, or <tt>null</tt> if empty.
396	>	* @throws ClassCastException {@inheritDoc}
397	>	* @throws NullPointerException if the specified element is null
398	>	*         and this set uses natural ordering, or its comparator
399	>	*         does not permit null elements
400	>	*/
401	>	public E ceiling(E e) {
402	>	return m.ceilingKey(e);
403	>	}
404	>
405	>	/**
406	>	* @throws ClassCastException {@inheritDoc}
407	>	* @throws NullPointerException if the specified element is null
408	>	*         and this set uses natural ordering, or its comparator
409	>	*         does not permit null elements
410		*/
411	+	public E higher(E e) {
412	+	return m.higherKey(e);
413	+	}
414	+
415		public E pollFirst() {
416		Map.Entry<E,?> e = m.pollFirstEntry();
417		return (e == null)? null : e.getKey();
418		}
419
520	–	/**
521	–	* Retrieves and removes the last (highest) element.
522	–	*
523	–	* @return the last element, or <tt>null</tt> if empty.
524	–	*/
420		public E pollLast() {
421		Map.Entry<E,?> e = m.pollLastEntry();
422		return (e == null)? null : e.getKey();
#	Line 531 | Line 426 | public class TreeSet<E>
426		* Returns a shallow copy of this <tt>TreeSet</tt> instance. (The elements
427		* themselves are not cloned.)
428		*
429	<	* @return a shallow copy of this set.
429	>	* @return a shallow copy of this set
430		*/
431		public Object clone() {
432		TreeSet<E> clone = null;
#	Line 551 | Line 446 | public class TreeSet<E>
446		* serialize it).
447		*
448		* @serialData Emits the comparator used to order this set, or
449	<	*             <tt>null</tt> if it obeys its elements' natural ordering
450	<	*             (Object), followed by the size of the set (the number of
451	<	*             elements it contains) (int), followed by all of its
452	<	*             elements (each an Object) in order (as determined by the
453	<	*             set's Comparator, or by the elements' natural ordering if
449	>	*             <tt>null</tt> if it obeys its elements' natural ordering
450	>	*             (Object), followed by the size of the set (the number of
451	>	*             elements it contains) (int), followed by all of its
452	>	*             elements (each an Object) in order (as determined by the
453	>	*             set's Comparator, or by the elements' natural ordering if
454		*             the set has no Comparator).
455		*/
456		private void writeObject(java.io.ObjectOutputStream s)
#	Line 584 | Line 479 | public class TreeSet<E>
479		s.defaultReadObject();
480
481		// Read in Comparator
482	<	Comparator<E> c = (Comparator<E>) s.readObject();
482	>	Comparator<? super E> c = (Comparator<? super E>) s.readObject();
483
484		// Create backing TreeMap
485		TreeMap<E,Object> tm;

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