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/* |
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* %W% %E% |
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* Copyright 1998-2006 Sun Microsystems, Inc. All Rights Reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* Copyright 2004 Sun Microsystems, Inc. All rights reserved. |
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* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Sun designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Sun in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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* CA 95054 USA or visit www.sun.com if you need additional information or |
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* have any questions. |
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*/ |
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|
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package java.util; |
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package java.util; |
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|
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/** |
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* This class implements the <tt>Set</tt> interface, backed by a |
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* <tt>TreeMap</tt> instance. This class guarantees that the sorted set will |
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* be in ascending element order, sorted according to the <i>natural order</i> |
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* of the elements (see <tt>Comparable</tt>), or by the comparator provided at |
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* set creation time, depending on which constructor is used.<p> |
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* A {@link NavigableSet} implementation based on a {@link TreeMap}. |
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* The elements are ordered using their {@linkplain Comparable natural |
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* ordering}, or by a {@link Comparator} provided at set creation |
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* time, depending on which constructor is used. |
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* |
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* This implementation provides guaranteed log(n) time cost for the basic |
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* operations (<tt>add</tt>, <tt>remove</tt> and <tt>contains</tt>).<p> |
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* <p>This implementation provides guaranteed log(n) time cost for the basic |
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* operations ({@code add}, {@code remove} and {@code contains}). |
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* |
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* Note that the ordering maintained by a set (whether or not an explicit |
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* <p>Note that the ordering maintained by a set (whether or not an explicit |
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* comparator is provided) must be <i>consistent with equals</i> if it is to |
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* correctly implement the <tt>Set</tt> interface. (See <tt>Comparable</tt> |
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* or <tt>Comparator</tt> for a precise definition of <i>consistent with |
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* equals</i>.) This is so because the <tt>Set</tt> interface is defined in |
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* terms of the <tt>equals</tt> operation, but a <tt>TreeSet</tt> instance |
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* performs all key comparisons using its <tt>compareTo</tt> (or |
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* <tt>compare</tt>) method, so two keys that are deemed equal by this method |
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* correctly implement the {@code Set} interface. (See {@code Comparable} |
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* or {@code Comparator} for a precise definition of <i>consistent with |
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* equals</i>.) This is so because the {@code Set} interface is defined in |
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* terms of the {@code equals} operation, but a {@code TreeSet} instance |
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* performs all element comparisons using its {@code compareTo} (or |
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* {@code compare}) method, so two elements that are deemed equal by this method |
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* are, from the standpoint of the set, equal. The behavior of a set |
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* <i>is</i> well-defined even if its ordering is inconsistent with equals; it |
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* just fails to obey the general contract of the <tt>Set</tt> interface.<p> |
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* just fails to obey the general contract of the {@code Set} interface. |
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* |
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* <b>Note that this implementation is not synchronized.</b> If multiple |
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* threads access a set concurrently, and at least one of the threads modifies |
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* the set, it <i>must</i> be synchronized externally. This is typically |
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* accomplished by synchronizing on some object that naturally encapsulates |
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* the set. If no such object exists, the set should be "wrapped" using the |
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* <tt>Collections.synchronizedSet</tt> method. This is best done at creation |
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* time, to prevent accidental unsynchronized access to the set: <pre> |
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* SortedSet s = Collections.synchronizedSortedSet(new TreeSet(...)); |
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* </pre><p> |
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* <p><strong>Note that this implementation is not synchronized.</strong> |
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* If multiple threads access a tree set concurrently, and at least one |
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* of the threads modifies the set, it <i>must</i> be synchronized |
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* externally. This is typically accomplished by synchronizing on some |
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* object that naturally encapsulates the set. |
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* If no such object exists, the set should be "wrapped" using the |
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* {@link Collections#synchronizedSortedSet Collections.synchronizedSortedSet} |
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* method. This is best done at creation time, to prevent accidental |
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* unsynchronized access to the set: <pre> |
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* SortedSet s = Collections.synchronizedSortedSet(new TreeSet(...));</pre> |
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* |
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* The Iterators returned by this class's <tt>iterator</tt> method are |
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* <p>The iterators returned by this class's {@code iterator} method are |
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* <i>fail-fast</i>: if the set is modified at any time after the iterator is |
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* created, in any way except through the iterator's own <tt>remove</tt> |
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* method, the iterator will throw a <tt>ConcurrentModificationException</tt>. |
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* created, in any way except through the iterator's own {@code remove} |
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* method, the iterator will throw a {@link ConcurrentModificationException}. |
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* Thus, in the face of concurrent modification, the iterator fails quickly |
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* and cleanly, rather than risking arbitrary, non-deterministic behavior at |
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* an undetermined time in the future. |
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* <p>Note that the fail-fast behavior of an iterator cannot be guaranteed |
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* as it is, generally speaking, impossible to make any hard guarantees in the |
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* presence of unsynchronized concurrent modification. Fail-fast iterators |
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* throw <tt>ConcurrentModificationException</tt> on a best-effort basis. |
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* throw {@code ConcurrentModificationException} on a best-effort basis. |
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* Therefore, it would be wrong to write a program that depended on this |
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* exception for its correctness: <i>the fail-fast behavior of iterators |
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* should be used only to detect bugs.</i><p> |
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* should be used only to detect bugs.</i> |
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* |
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* This class is a member of the |
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* <a href="{@docRoot}/../guide/collections/index.html"> |
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* <p>This class is a member of the |
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* <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
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* Java Collections Framework</a>. |
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* |
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* @param <E> the type of elements maintained by this set |
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* |
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* @author Josh Bloch |
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* @version %I%, %G% |
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* @see Collection |
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* @see HashSet |
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* @see Comparable |
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* @see Comparator |
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* @see Collections#synchronizedSortedSet(SortedSet) |
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* @see TreeMap |
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* @since 1.2 |
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*/ |
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|
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public class TreeSet<E> |
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extends AbstractSet<E> |
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public class TreeSet<E> extends AbstractSet<E> |
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implements NavigableSet<E>, Cloneable, java.io.Serializable |
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{ |
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private transient NavigableMap<E,Object> m; // The backing Map |
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/** |
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* The backing map. |
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*/ |
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private transient NavigableMap<E,Object> m; |
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|
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// Dummy value to associate with an Object in the backing Map |
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private static final Object PRESENT = new Object(); |
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|
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/** |
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* Constructs a set backed by the specified sorted map. |
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* Constructs a set backed by the specified navigable map. |
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*/ |
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private TreeSet(NavigableMap<E,Object> m) { |
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TreeSet(NavigableMap<E,Object> m) { |
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this.m = m; |
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} |
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/** |
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* Constructs a new, empty set, sorted according to the elements' natural |
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* order. All elements inserted into the set must implement the |
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* <tt>Comparable</tt> interface. Furthermore, all such elements must be |
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* <i>mutually comparable</i>: <tt>e1.compareTo(e2)</tt> must not throw a |
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* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and |
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* <tt>e2</tt> in the set. If the user attempts to add an element to the |
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* set that violates this constraint (for example, the user attempts to |
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* add a string element to a set whose elements are integers), the |
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* <tt>add(Object)</tt> call will throw a <tt>ClassCastException</tt>. |
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* |
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* @see Comparable |
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* Constructs a new, empty tree set, sorted according to the |
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* natural ordering of its elements. All elements inserted into |
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* the set must implement the {@link Comparable} interface. |
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* Furthermore, all such elements must be <i>mutually |
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* comparable</i>: {@code e1.compareTo(e2)} must not throw a |
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* {@code ClassCastException} for any elements {@code e1} and |
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* {@code e2} in the set. If the user attempts to add an element |
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* to the set that violates this constraint (for example, the user |
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* attempts to add a string element to a set whose elements are |
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* integers), the {@code add} call will throw a |
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* {@code ClassCastException}. |
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*/ |
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public TreeSet() { |
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this(new TreeMap<E,Object>()); |
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} |
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/** |
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* Constructs a new, empty set, sorted according to the specified |
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* Constructs a new, empty tree set, sorted according to the specified |
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* comparator. All elements inserted into the set must be <i>mutually |
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* comparable</i> by the specified comparator: <tt>comparator.compare(e1, |
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* e2)</tt> must not throw a <tt>ClassCastException</tt> for any elements |
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* <tt>e1</tt> and <tt>e2</tt> in the set. If the user attempts to add |
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* comparable</i> by the specified comparator: {@code comparator.compare(e1, |
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* e2)} must not throw a {@code ClassCastException} for any elements |
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* {@code e1} and {@code e2} in the set. If the user attempts to add |
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* an element to the set that violates this constraint, the |
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* <tt>add(Object)</tt> call will throw a <tt>ClassCastException</tt>. |
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* {@code add} call will throw a {@code ClassCastException}. |
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* |
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* @param c the comparator that will be used to sort this set. A |
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* <tt>null</tt> value indicates that the elements' <i>natural |
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* ordering</i> should be used. |
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* @param comparator the comparator that will be used to order this set. |
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* If {@code null}, the {@linkplain Comparable natural |
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* ordering} of the elements will be used. |
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*/ |
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public TreeSet(Comparator<? super E> c) { |
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this(new TreeMap<E,Object>(c)); |
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public TreeSet(Comparator<? super E> comparator) { |
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this(new TreeMap<E,Object>(comparator)); |
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} |
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/** |
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* Constructs a new set containing the elements in the specified |
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* collection, sorted according to the elements' <i>natural order</i>. |
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* All keys inserted into the set must implement the <tt>Comparable</tt> |
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* interface. Furthermore, all such keys must be <i>mutually |
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* comparable</i>: <tt>k1.compareTo(k2)</tt> must not throw a |
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* <tt>ClassCastException</tt> for any elements <tt>k1</tt> and |
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* <tt>k2</tt> in the set. |
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* Constructs a new tree set containing the elements in the specified |
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* collection, sorted according to the <i>natural ordering</i> of its |
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* elements. All elements inserted into the set must implement the |
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* {@link Comparable} interface. Furthermore, all such elements must be |
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* <i>mutually comparable</i>: {@code e1.compareTo(e2)} must not throw a |
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* {@code ClassCastException} for any elements {@code e1} and |
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* {@code e2} in the set. |
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* |
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* @param c The elements that will comprise the new set. |
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* |
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* @throws ClassCastException if the keys in the specified collection are |
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* not comparable, or are not mutually comparable. |
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* @throws NullPointerException if the specified collection is null. |
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* @param c collection whose elements will comprise the new set |
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* @throws ClassCastException if the elements in {@code c} are |
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* not {@link Comparable}, or are not mutually comparable |
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* @throws NullPointerException if the specified collection is null |
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*/ |
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public TreeSet(Collection<? extends E> c) { |
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this(); |
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} |
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|
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/** |
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* Constructs a new set containing the same elements as the specified |
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* sorted set, sorted according to the same ordering. |
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* Constructs a new tree set containing the same elements and |
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* using the same ordering as the specified sorted set. |
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* |
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* @param s sorted set whose elements will comprise the new set. |
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* @throws NullPointerException if the specified sorted set is null. |
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* @param s sorted set whose elements will comprise the new set |
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* @throws NullPointerException if the specified sorted set is null |
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*/ |
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public TreeSet(SortedSet<E> s) { |
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this(s.comparator()); |
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} |
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|
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/** |
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* Returns an iterator over the elements in this set. The elements |
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* are returned in ascending order. |
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* Returns an iterator over the elements in this set in ascending order. |
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* |
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* @return an iterator over the elements in this set. |
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* @return an iterator over the elements in this set in ascending order |
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*/ |
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public Iterator<E> iterator() { |
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return m.keySet().iterator(); |
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return m.navigableKeySet().iterator(); |
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} |
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|
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/** |
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* Returns an iterator over the elements in this set. The elements |
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* are returned in descending order. |
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* Returns an iterator over the elements in this set in descending order. |
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* |
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* @return an iterator over the elements in this set. |
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* @return an iterator over the elements in this set in descending order |
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* @since 1.6 |
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*/ |
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public Iterator<E> descendingIterator() { |
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return m.descendingKeySet().iterator(); |
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} |
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|
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/** |
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* @since 1.6 |
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*/ |
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public NavigableSet<E> descendingSet() { |
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return new TreeSet(m.descendingMap()); |
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} |
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|
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/** |
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* Returns the number of elements in this set (its cardinality). |
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* |
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* @return the number of elements in this set (its cardinality). |
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* @return the number of elements in this set (its cardinality) |
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*/ |
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public int size() { |
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return m.size(); |
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} |
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|
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/** |
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* Returns <tt>true</tt> if this set contains no elements. |
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* Returns {@code true} if this set contains no elements. |
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* |
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* @return <tt>true</tt> if this set contains no elements. |
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* @return {@code true} if this set contains no elements |
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*/ |
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public boolean isEmpty() { |
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return m.isEmpty(); |
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} |
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|
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/** |
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* Returns <tt>true</tt> if this set contains the specified element. |
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* |
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* @param o the object to be checked for containment in this set. |
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* @return <tt>true</tt> if this set contains the specified element. |
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* Returns {@code true} if this set contains the specified element. |
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* More formally, returns {@code true} if and only if this set |
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* contains an element {@code e} such that |
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* <tt>(o==null ? e==null : o.equals(e))</tt>. |
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* |
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* @param o object to be checked for containment in this set |
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* @return {@code true} if this set contains the specified element |
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* @throws ClassCastException if the specified object cannot be compared |
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* with the elements currently in the set. |
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* @throws NullPointerException o is <tt>null</tt> and this map |
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* uses natural ordering and is non-empty, or its comparator does |
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* not tolerate <tt>null</tt> keys. |
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* with the elements currently in the set |
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* @throws NullPointerException if the specified element is null |
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* and this set uses natural ordering, or its comparator |
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* does not permit null elements |
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*/ |
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public boolean contains(Object o) { |
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return m.containsKey(o); |
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|
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/** |
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* Adds the specified element to this set if it is not already present. |
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* |
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* @param o element to be added to this set. |
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* @return <tt>true</tt> if the set did not already contain the specified |
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* element. |
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* |
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* More formally, adds the specified element {@code e} to this set if |
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* the set contains no element {@code e2} such that |
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* <tt>(e==null ? e2==null : e.equals(e2))</tt>. |
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* If this set already contains the element, the call leaves the set |
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* unchanged and returns {@code false}. |
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* |
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* @param e element to be added to this set |
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* @return {@code true} if this set did not already contain the specified |
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* element |
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* @throws ClassCastException if the specified object cannot be compared |
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* with the elements currently in the set. |
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* @throws NullPointerException o is <tt>null</tt> and this map |
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* uses natural ordering and is non-empty, or its comparator does |
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* not tolerate <tt>null</tt> keys. |
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* with the elements currently in this set |
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* @throws NullPointerException if the specified element is null |
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* and this set uses natural ordering, or its comparator |
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* does not permit null elements |
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*/ |
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< |
public boolean add(E o) { |
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< |
return m.put(o, PRESENT)==null; |
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public boolean add(E e) { |
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> |
return m.put(e, PRESENT)==null; |
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} |
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|
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/** |
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* Removes the specified element from this set if it is present. |
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+ |
* More formally, removes an element {@code e} such that |
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* <tt>(o==null ? e==null : o.equals(e))</tt>, |
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* if this set contains such an element. Returns {@code true} if |
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* this set contained the element (or equivalently, if this set |
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* changed as a result of the call). (This set will not contain the |
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* element once the call returns.) |
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* |
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* @param o object to be removed from this set, if present. |
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* @return <tt>true</tt> if the set contained the specified element. |
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* |
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* @param o object to be removed from this set, if present |
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* @return {@code true} if this set contained the specified element |
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* @throws ClassCastException if the specified object cannot be compared |
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* with the elements currently in the set. |
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* @throws NullPointerException o is <tt>null</tt> and this map |
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* uses natural ordering and is non-empty, or its comparator does |
274 |
< |
* not tolerate <tt>null</tt> keys. |
271 |
> |
* with the elements currently in this set |
272 |
> |
* @throws NullPointerException if the specified element is null |
273 |
> |
* and this set uses natural ordering, or its comparator |
274 |
> |
* does not permit null elements |
275 |
|
*/ |
276 |
|
public boolean remove(Object o) { |
277 |
|
return m.remove(o)==PRESENT; |
279 |
|
|
280 |
|
/** |
281 |
|
* Removes all of the elements from this set. |
282 |
+ |
* The set will be empty after this call returns. |
283 |
|
*/ |
284 |
|
public void clear() { |
285 |
|
m.clear(); |
288 |
|
/** |
289 |
|
* Adds all of the elements in the specified collection to this set. |
290 |
|
* |
291 |
< |
* @param c elements to be added |
292 |
< |
* @return <tt>true</tt> if this set changed as a result of the call. |
255 |
< |
* |
291 |
> |
* @param c collection containing elements to be added to this set |
292 |
> |
* @return {@code true} if this set changed as a result of the call |
293 |
|
* @throws ClassCastException if the elements provided cannot be compared |
294 |
< |
* with the elements currently in the set. |
295 |
< |
* @throws NullPointerException of the specified collection is |
296 |
< |
* <tt>null</tt> or if any element is <tt>null</tt> and this map |
297 |
< |
* uses natural ordering, or its comparator does not tolerate |
261 |
< |
* <tt>null</tt> keys. |
294 |
> |
* with the elements currently in the set |
295 |
> |
* @throws NullPointerException if the specified collection is null or |
296 |
> |
* if any element is null and this set uses natural ordering, or |
297 |
> |
* its comparator does not permit null elements |
298 |
|
*/ |
299 |
|
public boolean addAll(Collection<? extends E> c) { |
300 |
|
// Use linear-time version if applicable |
301 |
|
if (m.size()==0 && c.size() > 0 && |
302 |
|
c instanceof SortedSet && |
303 |
|
m instanceof TreeMap) { |
304 |
< |
SortedSet<Map.Entry<E, Object>> set = (SortedSet<Map.Entry<E, Object>>) (SortedSet) c; |
304 |
> |
SortedSet<? extends E> set = (SortedSet<? extends E>) c; |
305 |
|
TreeMap<E,Object> map = (TreeMap<E, Object>) m; |
306 |
< |
Comparator<? super E> cc = (Comparator<E>) set.comparator(); |
306 |
> |
Comparator<? super E> cc = (Comparator<? super E>) set.comparator(); |
307 |
|
Comparator<? super E> mc = map.comparator(); |
308 |
|
if (cc==mc || (cc != null && cc.equals(mc))) { |
309 |
|
map.addAllForTreeSet(set, PRESENT); |
314 |
|
} |
315 |
|
|
316 |
|
/** |
317 |
< |
* Returns a view of the portion of this set whose elements range from |
318 |
< |
* <tt>fromElement</tt>, inclusive, to <tt>toElement</tt>, exclusive. (If |
319 |
< |
* <tt>fromElement</tt> and <tt>toElement</tt> are equal, the returned |
320 |
< |
* sorted set is empty.) The returned sorted set is backed by this set, |
321 |
< |
* so changes in the returned sorted set are reflected in this set, and |
322 |
< |
* vice-versa. The returned sorted set supports all optional Set |
323 |
< |
* operations.<p> |
324 |
< |
* |
325 |
< |
* The sorted set returned by this method will throw an |
326 |
< |
* <tt>IllegalArgumentException</tt> if the user attempts to insert an |
327 |
< |
* 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>. |
323 |
< |
* @throws NullPointerException if <tt>fromElement</tt> or |
324 |
< |
* <tt>toElement</tt> is <tt>null</tt> and this set uses natural |
325 |
< |
* order, or its comparator does not tolerate <tt>null</tt> |
326 |
< |
* elements. |
327 |
< |
*/ |
328 |
< |
public NavigableSet<E> subSet(E fromElement, E toElement) { |
329 |
< |
return new TreeSet<E>(m.subMap(fromElement, toElement)); |
330 |
< |
} |
331 |
< |
|
332 |
< |
/** |
333 |
< |
* Returns a view of the portion of this set whose elements are strictly |
334 |
< |
* less than <tt>toElement</tt>. The returned sorted set is backed by |
335 |
< |
* this set, so changes in the returned sorted set are reflected in this |
336 |
< |
* set, and vice-versa. The returned sorted set supports all optional set |
337 |
< |
* operations.<p> |
338 |
< |
* |
339 |
< |
* The sorted set returned by this method will throw an |
340 |
< |
* <tt>IllegalArgumentException</tt> if the user attempts to insert an |
341 |
< |
* element greater than or equal to <tt>toElement</tt>.<p> |
342 |
< |
* |
343 |
< |
* Note: this method always returns a view that does not contain its |
344 |
< |
* (high) endpoint. If you need a view that does contain this endpoint, |
345 |
< |
* and the element type allows for calculation of the successor of a |
346 |
< |
* specified value, merely request a headSet bounded by |
347 |
< |
* <tt>successor(highEndpoint)</tt>. For example, suppose that <tt>s</tt> |
348 |
< |
* is a sorted set of strings. The following idiom obtains a view |
349 |
< |
* containing all of the strings in <tt>s</tt> that are less than or equal |
350 |
< |
* to <tt>high</tt>: <pre> NavigableSet head = s.headSet(high+"\0");</pre> |
351 |
< |
* |
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)); |
317 |
> |
* @throws ClassCastException {@inheritDoc} |
318 |
> |
* @throws NullPointerException if {@code fromElement} or {@code toElement} |
319 |
> |
* is null and this set uses natural ordering, or its comparator |
320 |
> |
* does not permit null elements |
321 |
> |
* @throws IllegalArgumentException {@inheritDoc} |
322 |
> |
* @since 1.6 |
323 |
> |
*/ |
324 |
> |
public NavigableSet<E> subSet(E fromElement, boolean fromInclusive, |
325 |
> |
E toElement, boolean toInclusive) { |
326 |
> |
return new TreeSet<E>(m.subMap(fromElement, fromInclusive, |
327 |
> |
toElement, toInclusive)); |
328 |
|
} |
329 |
|
|
330 |
|
/** |
331 |
< |
* Returns the comparator used to order this sorted set, or <tt>null</tt> |
332 |
< |
* if this tree set uses its elements natural ordering. |
333 |
< |
* |
334 |
< |
* @return the comparator used to order this sorted set, or <tt>null</tt> |
335 |
< |
* if this tree set uses its elements natural ordering. |
331 |
> |
* @throws ClassCastException {@inheritDoc} |
332 |
> |
* @throws NullPointerException if {@code toElement} is null and |
333 |
> |
* this set uses natural ordering, or its comparator does |
334 |
> |
* not permit null elements |
335 |
> |
* @throws IllegalArgumentException {@inheritDoc} |
336 |
> |
* @since 1.6 |
337 |
> |
*/ |
338 |
> |
public NavigableSet<E> headSet(E toElement, boolean inclusive) { |
339 |
> |
return new TreeSet<E>(m.headMap(toElement, inclusive)); |
340 |
> |
} |
341 |
> |
|
342 |
> |
/** |
343 |
> |
* @throws ClassCastException {@inheritDoc} |
344 |
> |
* @throws NullPointerException if {@code fromElement} is null and |
345 |
> |
* this set uses natural ordering, or its comparator does |
346 |
> |
* not permit null elements |
347 |
> |
* @throws IllegalArgumentException {@inheritDoc} |
348 |
> |
* @since 1.6 |
349 |
> |
*/ |
350 |
> |
public NavigableSet<E> tailSet(E fromElement, boolean inclusive) { |
351 |
> |
return new TreeSet<E>(m.tailMap(fromElement, inclusive)); |
352 |
> |
} |
353 |
> |
|
354 |
> |
/** |
355 |
> |
* @throws ClassCastException {@inheritDoc} |
356 |
> |
* @throws NullPointerException if {@code fromElement} or |
357 |
> |
* {@code toElement} is null and this set uses natural ordering, |
358 |
> |
* or its comparator does not permit null elements |
359 |
> |
* @throws IllegalArgumentException {@inheritDoc} |
360 |
|
*/ |
361 |
+ |
public SortedSet<E> subSet(E fromElement, E toElement) { |
362 |
+ |
return subSet(fromElement, true, toElement, false); |
363 |
+ |
} |
364 |
+ |
|
365 |
+ |
/** |
366 |
+ |
* @throws ClassCastException {@inheritDoc} |
367 |
+ |
* @throws NullPointerException if {@code toElement} is null |
368 |
+ |
* and this set uses natural ordering, or its comparator does |
369 |
+ |
* not permit null elements |
370 |
+ |
* @throws IllegalArgumentException {@inheritDoc} |
371 |
+ |
*/ |
372 |
+ |
public SortedSet<E> headSet(E toElement) { |
373 |
+ |
return headSet(toElement, false); |
374 |
+ |
} |
375 |
+ |
|
376 |
+ |
/** |
377 |
+ |
* @throws ClassCastException {@inheritDoc} |
378 |
+ |
* @throws NullPointerException if {@code fromElement} is null |
379 |
+ |
* and this set uses natural ordering, or its comparator does |
380 |
+ |
* not permit null elements |
381 |
+ |
* @throws IllegalArgumentException {@inheritDoc} |
382 |
+ |
*/ |
383 |
+ |
public SortedSet<E> tailSet(E fromElement) { |
384 |
+ |
return tailSet(fromElement, true); |
385 |
+ |
} |
386 |
+ |
|
387 |
|
public Comparator<? super E> comparator() { |
388 |
|
return m.comparator(); |
389 |
|
} |
390 |
|
|
391 |
|
/** |
392 |
< |
* 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. |
392 |
> |
* @throws NoSuchElementException {@inheritDoc} |
393 |
|
*/ |
394 |
|
public E first() { |
395 |
|
return m.firstKey(); |
396 |
|
} |
397 |
|
|
398 |
|
/** |
399 |
< |
* 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. |
399 |
> |
* @throws NoSuchElementException {@inheritDoc} |
400 |
|
*/ |
401 |
|
public E last() { |
402 |
|
return m.lastKey(); |
404 |
|
|
405 |
|
// NavigableSet API methods |
406 |
|
|
407 |
+ |
/** |
408 |
+ |
* @throws ClassCastException {@inheritDoc} |
409 |
+ |
* @throws NullPointerException if the specified element is null |
410 |
+ |
* and this set uses natural ordering, or its comparator |
411 |
+ |
* does not permit null elements |
412 |
+ |
* @since 1.6 |
413 |
+ |
*/ |
414 |
+ |
public E lower(E e) { |
415 |
+ |
return m.lowerKey(e); |
416 |
+ |
} |
417 |
+ |
|
418 |
+ |
/** |
419 |
+ |
* @throws ClassCastException {@inheritDoc} |
420 |
+ |
* @throws NullPointerException if the specified element is null |
421 |
+ |
* and this set uses natural ordering, or its comparator |
422 |
+ |
* does not permit null elements |
423 |
+ |
* @since 1.6 |
424 |
+ |
*/ |
425 |
+ |
public E floor(E e) { |
426 |
+ |
return m.floorKey(e); |
427 |
+ |
} |
428 |
|
|
429 |
|
/** |
430 |
< |
* Returns an element greater than or equal to the given element, or |
431 |
< |
* <tt>null</tt> if there is no such element. |
432 |
< |
* |
433 |
< |
* @param o the value to match |
434 |
< |
* @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. |
430 |
> |
* @throws ClassCastException {@inheritDoc} |
431 |
> |
* @throws NullPointerException if the specified element is null |
432 |
> |
* and this set uses natural ordering, or its comparator |
433 |
> |
* does not permit null elements |
434 |
> |
* @since 1.6 |
435 |
|
*/ |
436 |
< |
public E higher(E o) { |
437 |
< |
return m.higherKey(o); |
436 |
> |
public E ceiling(E e) { |
437 |
> |
return m.ceilingKey(e); |
438 |
|
} |
439 |
|
|
440 |
|
/** |
441 |
< |
* Retrieves and removes the first (lowest) element. |
442 |
< |
* |
443 |
< |
* @return the least element, or <tt>null</tt> if empty. |
441 |
> |
* @throws ClassCastException {@inheritDoc} |
442 |
> |
* @throws NullPointerException if the specified element is null |
443 |
> |
* and this set uses natural ordering, or its comparator |
444 |
> |
* does not permit null elements |
445 |
> |
* @since 1.6 |
446 |
> |
*/ |
447 |
> |
public E higher(E e) { |
448 |
> |
return m.higherKey(e); |
449 |
> |
} |
450 |
> |
|
451 |
> |
/** |
452 |
> |
* @since 1.6 |
453 |
|
*/ |
454 |
|
public E pollFirst() { |
455 |
|
Map.Entry<E,?> e = m.pollFirstEntry(); |
457 |
|
} |
458 |
|
|
459 |
|
/** |
460 |
< |
* Retrieves and removes the last (highest) element. |
522 |
< |
* |
523 |
< |
* @return the last element, or <tt>null</tt> if empty. |
460 |
> |
* @since 1.6 |
461 |
|
*/ |
462 |
|
public E pollLast() { |
463 |
|
Map.Entry<E,?> e = m.pollLastEntry(); |
465 |
|
} |
466 |
|
|
467 |
|
/** |
468 |
< |
* Returns a shallow copy of this <tt>TreeSet</tt> instance. (The elements |
468 |
> |
* Returns a shallow copy of this {@code TreeSet} instance. (The elements |
469 |
|
* themselves are not cloned.) |
470 |
|
* |
471 |
< |
* @return a shallow copy of this set. |
471 |
> |
* @return a shallow copy of this set |
472 |
|
*/ |
473 |
|
public Object clone() { |
474 |
|
TreeSet<E> clone = null; |
479 |
|
} |
480 |
|
|
481 |
|
clone.m = new TreeMap<E,Object>(m); |
545 |
– |
|
482 |
|
return clone; |
483 |
|
} |
484 |
|
|
485 |
|
/** |
486 |
< |
* Save the state of the <tt>TreeSet</tt> instance to a stream (that is, |
486 |
> |
* Save the state of the {@code TreeSet} instance to a stream (that is, |
487 |
|
* serialize it). |
488 |
|
* |
489 |
|
* @serialData Emits the comparator used to order this set, or |
490 |
< |
* <tt>null</tt> if it obeys its elements' natural ordering |
491 |
< |
* (Object), followed by the size of the set (the number of |
492 |
< |
* elements it contains) (int), followed by all of its |
493 |
< |
* elements (each an Object) in order (as determined by the |
494 |
< |
* set's Comparator, or by the elements' natural ordering if |
490 |
> |
* {@code null} if it obeys its elements' natural ordering |
491 |
> |
* (Object), followed by the size of the set (the number of |
492 |
> |
* elements it contains) (int), followed by all of its |
493 |
> |
* elements (each an Object) in order (as determined by the |
494 |
> |
* set's Comparator, or by the elements' natural ordering if |
495 |
|
* the set has no Comparator). |
496 |
|
*/ |
497 |
|
private void writeObject(java.io.ObjectOutputStream s) |
511 |
|
} |
512 |
|
|
513 |
|
/** |
514 |
< |
* Reconstitute the <tt>TreeSet</tt> instance from a stream (that is, |
514 |
> |
* Reconstitute the {@code TreeSet} instance from a stream (that is, |
515 |
|
* deserialize it). |
516 |
|
*/ |
517 |
|
private void readObject(java.io.ObjectInputStream s) |
520 |
|
s.defaultReadObject(); |
521 |
|
|
522 |
|
// Read in Comparator |
523 |
< |
Comparator<E> c = (Comparator<E>) s.readObject(); |
523 |
> |
Comparator<? super E> c = (Comparator<? super E>) s.readObject(); |
524 |
|
|
525 |
|
// Create backing TreeMap |
526 |
|
TreeMap<E,Object> tm; |