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/* |
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* %W% %E% |
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* Copyright (c) 2003, 2013, Oracle and/or its affiliates. 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 2005 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. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package java.util; |
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import java.util.*; // for javadoc (till 6280605 is fixed) |
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|
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import java.util.function.Consumer; |
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/** |
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* An unbounded priority {@linkplain Queue queue} based on a priority |
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* heap. The elements of the priority queue are ordered according to |
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* their {@linkplain Comparable natural ordering}, or by a {@link |
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* Comparator} provided at queue construction time, depending on which |
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* constructor is used. A priority queue does not permit |
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* <tt>null</tt> elements. A priority queue relying on natural |
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* ordering also does not permit insertion of non-comparable objects |
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* (doing so may result in <tt>ClassCastException</tt>). |
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* An unbounded priority {@linkplain Queue queue} based on a priority heap. |
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* The elements of the priority queue are ordered according to their |
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* {@linkplain Comparable natural ordering}, or by a {@link Comparator} |
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* provided at queue construction time, depending on which constructor is |
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* used. A priority queue does not permit {@code null} elements. |
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* A priority queue relying on natural ordering also does not permit |
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* insertion of non-comparable objects (doing so may result in |
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* {@code ClassCastException}). |
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* |
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* <p>The <em>head</em> of this queue is the <em>least</em> element |
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* with respect to the specified ordering. If multiple elements are |
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* tied for least value, the head is one of those elements -- ties are |
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* broken arbitrarily. The queue retrieval operations <tt>poll</tt>, |
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* <tt>remove</tt>, <tt>peek</tt>, and <tt>element</tt> access the |
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* broken arbitrarily. The queue retrieval operations {@code poll}, |
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* {@code remove}, {@code peek}, and {@code element} access the |
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* element at the head of the queue. |
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* |
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* <p>A priority queue is unbounded, but has an internal |
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* Iterator} interfaces. The Iterator provided in method {@link |
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* #iterator()} is <em>not</em> guaranteed to traverse the elements of |
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* the priority queue in any particular order. If you need ordered |
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* traversal, consider using <tt>Arrays.sort(pq.toArray())</tt>. |
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* traversal, consider using {@code Arrays.sort(pq.toArray())}. |
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* |
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* <p> <strong>Note that this implementation is not synchronized.</strong> |
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* Multiple threads should not access a <tt>PriorityQueue</tt> |
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* instance concurrently if any of the threads modifies the list |
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* structurally. Instead, use the thread-safe {@link |
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* <p><strong>Note that this implementation is not synchronized.</strong> |
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* Multiple threads should not access a {@code PriorityQueue} |
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* instance concurrently if any of the threads modifies the queue. |
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* Instead, use the thread-safe {@link |
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* java.util.concurrent.PriorityBlockingQueue} class. |
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* |
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* <p>Implementation note: this implementation provides O(log(n)) time |
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* for the insertion methods (<tt>offer</tt>, <tt>poll</tt>, |
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* <tt>remove()</tt> and <tt>add</tt>) methods; linear time for the |
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* <tt>remove(Object)</tt> and <tt>contains(Object)</tt> methods; and |
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* constant time for the retrieval methods (<tt>peek</tt>, |
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* <tt>element</tt>, and <tt>size</tt>). |
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* <p>Implementation note: this implementation provides |
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* O(log(n)) time for the enqueuing and dequeuing methods |
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* ({@code offer}, {@code poll}, {@code remove()} and {@code add}); |
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* linear time for the {@code remove(Object)} and {@code contains(Object)} |
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* methods; and constant time for the retrieval methods |
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* ({@code peek}, {@code element}, and {@code size}). |
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* |
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* <p>This class is a member of the |
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* <a href="{@docRoot}/../guide/collections/index.html"> |
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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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* @since 1.5 |
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* @version 1.8, 08/27/05 |
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* @author Josh Bloch |
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* @param <E> the type of elements held in this collection |
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* @author Josh Bloch, Doug Lea |
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* @param <E> the type of elements held in this queue |
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*/ |
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public class PriorityQueue<E> extends AbstractQueue<E> |
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implements java.io.Serializable { |
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* heap and each descendant d of n, n <= d. The element with the |
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* lowest value is in queue[0], assuming the queue is nonempty. |
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*/ |
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private transient Object[] queue; |
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transient Object[] queue; // non-private to simplify nested class access |
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|
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/** |
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* The number of elements in the priority queue. |
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*/ |
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private int size = 0; |
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int size; |
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|
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/** |
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* The comparator, or null if priority queue uses elements' |
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* The number of times this priority queue has been |
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* <i>structurally modified</i>. See AbstractList for gory details. |
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*/ |
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private transient int modCount = 0; |
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transient int modCount; // non-private to simplify nested class access |
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|
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/** |
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* Creates a <tt>PriorityQueue</tt> with the default initial |
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* Creates a {@code PriorityQueue} with the default initial |
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* capacity (11) that orders its elements according to their |
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* {@linkplain Comparable natural ordering}. |
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*/ |
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} |
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|
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/** |
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* Creates a <tt>PriorityQueue</tt> with the specified initial |
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* Creates a {@code PriorityQueue} with the specified initial |
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* capacity that orders its elements according to their |
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* {@linkplain Comparable natural ordering}. |
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* |
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* @param initialCapacity the initial capacity for this priority queue |
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* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less |
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* than 1 |
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* @throws IllegalArgumentException if {@code initialCapacity} is less |
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* than 1 |
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*/ |
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public PriorityQueue(int initialCapacity) { |
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this(initialCapacity, null); |
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} |
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|
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/** |
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* Creates a <tt>PriorityQueue</tt> with the specified initial capacity |
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* Creates a {@code PriorityQueue} with the default initial capacity and |
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* whose elements are ordered according to the specified comparator. |
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* |
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* @param comparator the comparator that will be used to order this |
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* priority queue. If {@code null}, the {@linkplain Comparable |
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* natural ordering} of the elements will be used. |
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* @since 1.8 |
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*/ |
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public PriorityQueue(Comparator<? super E> comparator) { |
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this(DEFAULT_INITIAL_CAPACITY, comparator); |
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} |
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|
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/** |
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* Creates a {@code PriorityQueue} with the specified initial capacity |
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* that orders its elements according to the specified comparator. |
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* |
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* @param initialCapacity the initial capacity for this priority queue |
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* @param comparator the comparator that will be used to order |
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* this priority queue. If <tt>null</tt>, the <i>natural |
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* ordering</i> of the elements will be used. |
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* @throws IllegalArgumentException if <tt>initialCapacity</tt> is |
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* @param comparator the comparator that will be used to order this |
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* priority queue. If {@code null}, the {@linkplain Comparable |
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* natural ordering} of the elements will be used. |
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* @throws IllegalArgumentException if {@code initialCapacity} is |
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* less than 1 |
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*/ |
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public PriorityQueue(int initialCapacity, |
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} |
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|
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/** |
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* Creates a <tt>PriorityQueue</tt> containing the elements in the |
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* specified collection. If the specified collection is an |
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* instance of a {@link java.util.SortedSet} or is another |
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* <tt>PriorityQueue</tt>, the priority queue will be ordered |
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* according to the same ordering. Otherwise, this priority queue |
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* will be ordered according to the natural ordering of its elements. |
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* Creates a {@code PriorityQueue} containing the elements in the |
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* specified collection. If the specified collection is an instance of |
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* a {@link SortedSet} or is another {@code PriorityQueue}, this |
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* priority queue will be ordered according to the same ordering. |
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* Otherwise, this priority queue will be ordered according to the |
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* {@linkplain Comparable natural ordering} of its elements. |
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* |
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* @param c the collection whose elements are to be placed |
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* into this priority queue |
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* @throws NullPointerException if the specified collection or any |
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* of its elements are null |
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*/ |
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@SuppressWarnings("unchecked") |
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public PriorityQueue(Collection<? extends E> c) { |
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initFromCollection(c); |
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if (c instanceof SortedSet) |
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comparator = (Comparator<? super E>) |
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((SortedSet<? extends E>)c).comparator(); |
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else if (c instanceof PriorityQueue) |
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comparator = (Comparator<? super E>) |
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((PriorityQueue<? extends E>)c).comparator(); |
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if (c instanceof SortedSet<?>) { |
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SortedSet<? extends E> ss = (SortedSet<? extends E>) c; |
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this.comparator = (Comparator<? super E>) ss.comparator(); |
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initElementsFromCollection(ss); |
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} |
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else if (c instanceof PriorityQueue<?>) { |
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PriorityQueue<? extends E> pq = (PriorityQueue<? extends E>) c; |
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this.comparator = (Comparator<? super E>) pq.comparator(); |
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initFromPriorityQueue(pq); |
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} |
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else { |
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comparator = null; |
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heapify(); |
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this.comparator = null; |
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initFromCollection(c); |
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} |
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} |
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|
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/** |
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* Creates a <tt>PriorityQueue</tt> containing the elements in the |
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* Creates a {@code PriorityQueue} containing the elements in the |
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* specified priority queue. This priority queue will be |
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* ordered according to the same ordering as the given priority |
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* queue. |
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* |
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* @param c the priority queue whose elements are to be placed |
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* into this priority queue |
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* @throws ClassCastException if elements of <tt>c</tt> cannot be |
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* compared to one another according to <tt>c</tt>'s |
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* @throws ClassCastException if elements of {@code c} cannot be |
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* compared to one another according to {@code c}'s |
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* ordering |
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* @throws NullPointerException if the specified priority queue or any |
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* of its elements are null |
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*/ |
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@SuppressWarnings("unchecked") |
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public PriorityQueue(PriorityQueue<? extends E> c) { |
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comparator = (Comparator<? super E>)c.comparator(); |
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initFromCollection(c); |
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this.comparator = (Comparator<? super E>) c.comparator(); |
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initFromPriorityQueue(c); |
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} |
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|
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/** |
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* Creates a <tt>PriorityQueue</tt> containing the elements in the |
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* specified sorted set. This priority queue will be ordered |
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* Creates a {@code PriorityQueue} containing the elements in the |
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* specified sorted set. This priority queue will be ordered |
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* according to the same ordering as the given sorted set. |
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* |
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* @param c the sorted set whose elements are to be placed |
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* into this priority queue. |
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* into this priority queue |
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* @throws ClassCastException if elements of the specified sorted |
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* set cannot be compared to one another according to the |
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* sorted set's ordering |
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* @throws NullPointerException if the specified sorted set or any |
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* of its elements are null |
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*/ |
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@SuppressWarnings("unchecked") |
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public PriorityQueue(SortedSet<? extends E> c) { |
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comparator = (Comparator<? super E>)c.comparator(); |
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initFromCollection(c); |
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this.comparator = (Comparator<? super E>) c.comparator(); |
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initElementsFromCollection(c); |
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} |
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|
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/** |
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* Initialize queue array with elements from the given Collection. |
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* @param c the collection |
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*/ |
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private void initFromCollection(Collection<? extends E> c) { |
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private void initFromPriorityQueue(PriorityQueue<? extends E> c) { |
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if (c.getClass() == PriorityQueue.class) { |
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this.queue = c.toArray(); |
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this.size = c.size(); |
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} else { |
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initFromCollection(c); |
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} |
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} |
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|
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private void initElementsFromCollection(Collection<? extends E> c) { |
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Object[] a = c.toArray(); |
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// If c.toArray incorrectly doesn't return Object[], copy it. |
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if (a.getClass() != Object[].class) |
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a = Arrays.copyOf(a, a.length, Object[].class); |
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queue = a; |
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size = a.length; |
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int len = a.length; |
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if (len == 1 || this.comparator != null) |
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for (Object e : a) |
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if (e == null) |
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throw new NullPointerException(); |
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this.queue = a; |
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this.size = a.length; |
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} |
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|
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/** |
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* Initializes queue array with elements from the given Collection. |
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* |
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* @param c the collection |
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*/ |
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private void initFromCollection(Collection<? extends E> c) { |
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initElementsFromCollection(c); |
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heapify(); |
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} |
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|
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/** |
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* The maximum size of array to allocate. |
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* Some VMs reserve some header words in an array. |
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* Attempts to allocate larger arrays may result in |
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* OutOfMemoryError: Requested array size exceeds VM limit |
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*/ |
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private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; |
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|
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/** |
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* Increases the capacity of the array. |
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* |
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* @param minCapacity the desired minimum capacity |
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*/ |
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private void grow(int minCapacity) { |
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if (minCapacity < 0) // overflow |
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throw new OutOfMemoryError(); |
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int oldCapacity = queue.length; |
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int oldCapacity = queue.length; |
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// Double size if small; else grow by 50% |
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int newCapacity = ((oldCapacity < 64)? |
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((oldCapacity + 1) * 2): |
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((oldCapacity / 2) * 3)); |
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if (newCapacity < 0) // overflow |
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newCapacity = Integer.MAX_VALUE; |
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if (newCapacity < minCapacity) |
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newCapacity = minCapacity; |
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int newCapacity = oldCapacity + ((oldCapacity < 64) ? |
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(oldCapacity + 2) : |
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(oldCapacity >> 1)); |
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// overflow-conscious code |
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if (newCapacity - MAX_ARRAY_SIZE > 0) |
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newCapacity = hugeCapacity(minCapacity); |
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queue = Arrays.copyOf(queue, newCapacity); |
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} |
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|
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private static int hugeCapacity(int minCapacity) { |
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if (minCapacity < 0) // overflow |
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throw new OutOfMemoryError(); |
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return (minCapacity > MAX_ARRAY_SIZE) ? |
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Integer.MAX_VALUE : |
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MAX_ARRAY_SIZE; |
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} |
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|
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/** |
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* Inserts the specified element into this priority queue. |
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* |
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< |
* @return <tt>true</tt> (as specified by {@link Collection#add}) |
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* @return {@code true} (as specified by {@link Collection#add}) |
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* @throws ClassCastException if the specified element cannot be |
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* compared with elements currently in this priority queue |
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* according to the priority queue's ordering |
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/** |
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* Inserts the specified element into this priority queue. |
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* |
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* @return <tt>true</tt> (as specified by {@link Queue#offer}) |
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> |
* @return {@code true} (as specified by {@link Queue#offer}) |
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* @throws ClassCastException if the specified element cannot be |
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* compared with elements currently in this priority queue |
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* according to the priority queue's ordering |
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return true; |
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} |
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|
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+ |
@SuppressWarnings("unchecked") |
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public E peek() { |
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< |
if (size == 0) |
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return null; |
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return (E) queue[0]; |
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> |
return (size == 0) ? null : (E) queue[0]; |
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} |
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|
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private int indexOf(Object o) { |
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< |
if (o != null) { |
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> |
if (o != null) { |
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for (int i = 0; i < size; i++) |
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if (o.equals(queue[i])) |
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return i; |
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|
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/** |
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* Removes a single instance of the specified element from this queue, |
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* if it is present. More formally, removes an element <tt>e</tt> such |
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* that <tt>o.equals(e)</tt>, if this queue contains one or more such |
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* elements. Returns true if this queue contained the specified element |
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* (or equivalently, if this queue changed as a result of the call). |
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* if it is present. More formally, removes an element {@code e} such |
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* that {@code o.equals(e)}, if this queue contains one or more such |
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> |
* elements. Returns {@code true} if and only if this queue contained |
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> |
* the specified element (or equivalently, if this queue changed as a |
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> |
* result of the call). |
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* |
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* @param o element to be removed from this queue, if present |
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< |
* @return <tt>true</tt> if this queue changed as a result of the call |
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* @return {@code true} if this queue changed as a result of the call |
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*/ |
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public boolean remove(Object o) { |
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< |
int i = indexOf(o); |
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< |
if (i == -1) |
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< |
return false; |
377 |
< |
else { |
378 |
< |
removeAt(i); |
379 |
< |
return true; |
380 |
< |
} |
374 |
> |
int i = indexOf(o); |
375 |
> |
if (i == -1) |
376 |
> |
return false; |
377 |
> |
else { |
378 |
> |
removeAt(i); |
379 |
> |
return true; |
380 |
> |
} |
381 |
|
} |
382 |
|
|
383 |
|
/** |
384 |
|
* Version of remove using reference equality, not equals. |
385 |
< |
* Needed by iterator.remove |
385 |
> |
* Needed by iterator.remove. |
386 |
|
* |
387 |
|
* @param o element to be removed from this queue, if present |
388 |
< |
* @return <tt>true</tt> if removed. |
388 |
> |
* @return {@code true} if removed |
389 |
|
*/ |
390 |
|
boolean removeEq(Object o) { |
391 |
< |
for (int i = 0; i < size; i++) { |
392 |
< |
if (o == queue[i]) { |
391 |
> |
for (int i = 0; i < size; i++) { |
392 |
> |
if (o == queue[i]) { |
393 |
|
removeAt(i); |
394 |
|
return true; |
395 |
|
} |
398 |
|
} |
399 |
|
|
400 |
|
/** |
401 |
< |
* Returns <tt>true</tt> if this queue contains the specified element. |
402 |
< |
* More formally, returns <tt>true</tt> if and only if this queue contains |
403 |
< |
* at least one element <tt>e</tt> such that <tt>o.equals(e)</tt>. |
401 |
> |
* Returns {@code true} if this queue contains the specified element. |
402 |
> |
* More formally, returns {@code true} if and only if this queue contains |
403 |
> |
* at least one element {@code e} such that {@code o.equals(e)}. |
404 |
|
* |
405 |
|
* @param o object to be checked for containment in this queue |
406 |
< |
* @return <tt>true</tt> if this queue contains the specified element |
406 |
> |
* @return {@code true} if this queue contains the specified element |
407 |
|
*/ |
408 |
|
public boolean contains(Object o) { |
409 |
< |
return indexOf(o) != -1; |
409 |
> |
return indexOf(o) >= 0; |
410 |
|
} |
411 |
|
|
412 |
|
/** |
413 |
< |
* Returns an array containing all of the elements in this queue, |
413 |
> |
* Returns an array containing all of the elements in this queue. |
414 |
|
* The elements are in no particular order. |
415 |
|
* |
416 |
|
* <p>The returned array will be "safe" in that no references to it are |
417 |
< |
* maintained by this list. (In other words, this method must allocate |
417 |
> |
* maintained by this queue. (In other words, this method must allocate |
418 |
|
* a new array). The caller is thus free to modify the returned array. |
419 |
|
* |
420 |
< |
* @return an array containing all of the elements in this queue. |
420 |
> |
* <p>This method acts as bridge between array-based and collection-based |
421 |
> |
* APIs. |
422 |
> |
* |
423 |
> |
* @return an array containing all of the elements in this queue |
424 |
|
*/ |
425 |
|
public Object[] toArray() { |
426 |
|
return Arrays.copyOf(queue, size); |
427 |
|
} |
428 |
|
|
429 |
|
/** |
430 |
< |
* Returns an array containing all of the elements in this queue. |
431 |
< |
* The elements are in no particular order. The runtime type of |
432 |
< |
* the returned array is that of the specified array. If the queue |
433 |
< |
* fits in the specified array, it is returned therein. |
434 |
< |
* Otherwise, a new array is allocated with the runtime type of |
435 |
< |
* the specified array and the size of this queue. |
430 |
> |
* Returns an array containing all of the elements in this queue; the |
431 |
> |
* runtime type of the returned array is that of the specified array. |
432 |
> |
* The returned array elements are in no particular order. |
433 |
> |
* If the queue fits in the specified array, it is returned therein. |
434 |
> |
* Otherwise, a new array is allocated with the runtime type of the |
435 |
> |
* specified array and the size of this queue. |
436 |
|
* |
437 |
|
* <p>If the queue fits in the specified array with room to spare |
438 |
|
* (i.e., the array has more elements than the queue), the element in |
439 |
|
* the array immediately following the end of the collection is set to |
440 |
< |
* <tt>null</tt>. (This is useful in determining the length of the |
441 |
< |
* queue <i>only</i> if the caller knows that the queue does not contain |
442 |
< |
* any null elements.) |
440 |
> |
* {@code null}. |
441 |
> |
* |
442 |
> |
* <p>Like the {@link #toArray()} method, this method acts as bridge between |
443 |
> |
* array-based and collection-based APIs. Further, this method allows |
444 |
> |
* precise control over the runtime type of the output array, and may, |
445 |
> |
* under certain circumstances, be used to save allocation costs. |
446 |
> |
* |
447 |
> |
* <p>Suppose {@code x} is a queue known to contain only strings. |
448 |
> |
* The following code can be used to dump the queue into a newly |
449 |
> |
* allocated array of {@code String}: |
450 |
> |
* |
451 |
> |
* <pre> {@code String[] y = x.toArray(new String[0]);}</pre> |
452 |
> |
* |
453 |
> |
* Note that {@code toArray(new Object[0])} is identical in function to |
454 |
> |
* {@code toArray()}. |
455 |
|
* |
456 |
|
* @param a the array into which the elements of the queue are to |
457 |
|
* be stored, if it is big enough; otherwise, a new array of the |
458 |
|
* same runtime type is allocated for this purpose. |
459 |
< |
* @return an array containing the elements of the queue |
459 |
> |
* @return an array containing all of the elements in this queue |
460 |
|
* @throws ArrayStoreException if the runtime type of the specified array |
461 |
|
* is not a supertype of the runtime type of every element in |
462 |
|
* this queue |
463 |
|
* @throws NullPointerException if the specified array is null |
464 |
|
*/ |
465 |
+ |
@SuppressWarnings("unchecked") |
466 |
|
public <T> T[] toArray(T[] a) { |
467 |
+ |
final int size = this.size; |
468 |
|
if (a.length < size) |
469 |
|
// Make a new array of a's runtime type, but my contents: |
470 |
|
return (T[]) Arrays.copyOf(queue, size, a.getClass()); |
471 |
< |
System.arraycopy(queue, 0, a, 0, size); |
471 |
> |
System.arraycopy(queue, 0, a, 0, size); |
472 |
|
if (a.length > size) |
473 |
|
a[size] = null; |
474 |
|
return a; |
489 |
|
* Index (into queue array) of element to be returned by |
490 |
|
* subsequent call to next. |
491 |
|
*/ |
492 |
< |
private int cursor = 0; |
492 |
> |
private int cursor; |
493 |
|
|
494 |
|
/** |
495 |
|
* Index of element returned by most recent call to next, |
507 |
|
* after we've completed the "normal" iteration. |
508 |
|
* |
509 |
|
* We expect that most iterations, even those involving removals, |
510 |
< |
* will not use need to store elements in this field. |
510 |
> |
* will not need to store elements in this field. |
511 |
|
*/ |
512 |
< |
private ArrayDeque<E> forgetMeNot = null; |
512 |
> |
private ArrayDeque<E> forgetMeNot; |
513 |
|
|
514 |
|
/** |
515 |
|
* Element returned by the most recent call to next iff that |
516 |
|
* element was drawn from the forgetMeNot list. |
517 |
|
*/ |
518 |
< |
private E lastRetElt = null; |
518 |
> |
private E lastRetElt; |
519 |
|
|
520 |
|
/** |
521 |
|
* The modCount value that the iterator believes that the backing |
522 |
< |
* List should have. If this expectation is violated, the iterator |
522 |
> |
* Queue should have. If this expectation is violated, the iterator |
523 |
|
* has detected concurrent modification. |
524 |
|
*/ |
525 |
|
private int expectedModCount = modCount; |
529 |
|
(forgetMeNot != null && !forgetMeNot.isEmpty()); |
530 |
|
} |
531 |
|
|
532 |
+ |
@SuppressWarnings("unchecked") |
533 |
|
public E next() { |
534 |
|
if (expectedModCount != modCount) |
535 |
|
throw new ConcurrentModificationException(); |
547 |
|
public void remove() { |
548 |
|
if (expectedModCount != modCount) |
549 |
|
throw new ConcurrentModificationException(); |
461 |
– |
if (lastRet == -1 && lastRetElt == null) |
462 |
– |
throw new IllegalStateException(); |
550 |
|
if (lastRet != -1) { |
551 |
|
E moved = PriorityQueue.this.removeAt(lastRet); |
552 |
|
lastRet = -1; |
554 |
|
cursor--; |
555 |
|
else { |
556 |
|
if (forgetMeNot == null) |
557 |
< |
forgetMeNot = new ArrayDeque<E>(); |
557 |
> |
forgetMeNot = new ArrayDeque<>(); |
558 |
|
forgetMeNot.add(moved); |
559 |
|
} |
560 |
< |
} else { |
560 |
> |
} else if (lastRetElt != null) { |
561 |
|
PriorityQueue.this.removeEq(lastRetElt); |
562 |
|
lastRetElt = null; |
563 |
+ |
} else { |
564 |
+ |
throw new IllegalStateException(); |
565 |
|
} |
566 |
|
expectedModCount = modCount; |
567 |
|
} |
479 |
– |
|
568 |
|
} |
569 |
|
|
570 |
|
public int size() { |
582 |
|
size = 0; |
583 |
|
} |
584 |
|
|
585 |
+ |
@SuppressWarnings("unchecked") |
586 |
|
public E poll() { |
587 |
|
if (size == 0) |
588 |
|
return null; |
589 |
|
int s = --size; |
590 |
|
modCount++; |
591 |
< |
E result = (E)queue[0]; |
592 |
< |
E x = (E)queue[s]; |
591 |
> |
E result = (E) queue[0]; |
592 |
> |
E x = (E) queue[s]; |
593 |
|
queue[s] = null; |
594 |
|
if (s != 0) |
595 |
|
siftDown(0, x); |
606 |
|
* i. Under these circumstances, this method returns the element |
607 |
|
* that was previously at the end of the list and is now at some |
608 |
|
* position before i. This fact is used by iterator.remove so as to |
609 |
< |
* avoid missing traverseing elements. |
609 |
> |
* avoid missing traversing elements. |
610 |
|
*/ |
611 |
< |
private E removeAt(int i) { |
612 |
< |
assert i >= 0 && i < size; |
611 |
> |
@SuppressWarnings("unchecked") |
612 |
> |
E removeAt(int i) { |
613 |
> |
// assert i >= 0 && i < size; |
614 |
|
modCount++; |
615 |
|
int s = --size; |
616 |
|
if (s == i) // removed last element |
647 |
|
siftUpComparable(k, x); |
648 |
|
} |
649 |
|
|
650 |
+ |
@SuppressWarnings("unchecked") |
651 |
|
private void siftUpComparable(int k, E x) { |
652 |
|
Comparable<? super E> key = (Comparable<? super E>) x; |
653 |
|
while (k > 0) { |
654 |
|
int parent = (k - 1) >>> 1; |
655 |
|
Object e = queue[parent]; |
656 |
< |
if (key.compareTo((E)e) >= 0) |
656 |
> |
if (key.compareTo((E) e) >= 0) |
657 |
|
break; |
658 |
|
queue[k] = e; |
659 |
|
k = parent; |
661 |
|
queue[k] = key; |
662 |
|
} |
663 |
|
|
664 |
+ |
@SuppressWarnings("unchecked") |
665 |
|
private void siftUpUsingComparator(int k, E x) { |
666 |
|
while (k > 0) { |
667 |
|
int parent = (k - 1) >>> 1; |
668 |
|
Object e = queue[parent]; |
669 |
< |
if (comparator.compare(x, (E)e) >= 0) |
669 |
> |
if (comparator.compare(x, (E) e) >= 0) |
670 |
|
break; |
671 |
|
queue[k] = e; |
672 |
|
k = parent; |
689 |
|
siftDownComparable(k, x); |
690 |
|
} |
691 |
|
|
692 |
+ |
@SuppressWarnings("unchecked") |
693 |
|
private void siftDownComparable(int k, E x) { |
694 |
|
Comparable<? super E> key = (Comparable<? super E>)x; |
695 |
|
int half = size >>> 1; // loop while a non-leaf |
698 |
|
Object c = queue[child]; |
699 |
|
int right = child + 1; |
700 |
|
if (right < size && |
701 |
< |
((Comparable<? super E>)c).compareTo((E)queue[right]) > 0) |
701 |
> |
((Comparable<? super E>) c).compareTo((E) queue[right]) > 0) |
702 |
|
c = queue[child = right]; |
703 |
< |
if (key.compareTo((E)c) <= 0) |
703 |
> |
if (key.compareTo((E) c) <= 0) |
704 |
|
break; |
705 |
|
queue[k] = c; |
706 |
|
k = child; |
708 |
|
queue[k] = key; |
709 |
|
} |
710 |
|
|
711 |
+ |
@SuppressWarnings("unchecked") |
712 |
|
private void siftDownUsingComparator(int k, E x) { |
713 |
|
int half = size >>> 1; |
714 |
|
while (k < half) { |
716 |
|
Object c = queue[child]; |
717 |
|
int right = child + 1; |
718 |
|
if (right < size && |
719 |
< |
comparator.compare((E)c, (E)queue[right]) > 0) |
719 |
> |
comparator.compare((E) c, (E) queue[right]) > 0) |
720 |
|
c = queue[child = right]; |
721 |
< |
if (comparator.compare(x, (E)c) <= 0) |
721 |
> |
if (comparator.compare(x, (E) c) <= 0) |
722 |
|
break; |
723 |
|
queue[k] = c; |
724 |
|
k = child; |
730 |
|
* Establishes the heap invariant (described above) in the entire tree, |
731 |
|
* assuming nothing about the order of the elements prior to the call. |
732 |
|
*/ |
733 |
+ |
@SuppressWarnings("unchecked") |
734 |
|
private void heapify() { |
735 |
|
for (int i = (size >>> 1) - 1; i >= 0; i--) |
736 |
< |
siftDown(i, (E)queue[i]); |
736 |
> |
siftDown(i, (E) queue[i]); |
737 |
|
} |
738 |
|
|
739 |
|
/** |
740 |
|
* Returns the comparator used to order the elements in this |
741 |
< |
* queue, or <tt>null</tt> if this queue is sorted according to |
741 |
> |
* queue, or {@code null} if this queue is sorted according to |
742 |
|
* the {@linkplain Comparable natural ordering} of its elements. |
743 |
|
* |
744 |
|
* @return the comparator used to order this queue, or |
745 |
< |
* <tt>null</tt> if this queue is sorted according to the |
746 |
< |
* natural ordering of its elements. |
745 |
> |
* {@code null} if this queue is sorted according to the |
746 |
> |
* natural ordering of its elements |
747 |
|
*/ |
748 |
|
public Comparator<? super E> comparator() { |
749 |
|
return comparator; |
750 |
|
} |
751 |
|
|
752 |
|
/** |
753 |
< |
* Save the state of the instance to a stream (that |
659 |
< |
* is, serialize it). |
753 |
> |
* Saves this queue to a stream (that is, serializes it). |
754 |
|
* |
755 |
|
* @serialData The length of the array backing the instance is |
756 |
< |
* emitted (int), followed by all of its elements (each an |
757 |
< |
* <tt>Object</tt>) in the proper order. |
756 |
> |
* emitted (int), followed by all of its elements |
757 |
> |
* (each an {@code Object}) in the proper order. |
758 |
|
* @param s the stream |
759 |
+ |
* @throws java.io.IOException if an I/O error occurs |
760 |
|
*/ |
761 |
|
private void writeObject(java.io.ObjectOutputStream s) |
762 |
< |
throws java.io.IOException{ |
762 |
> |
throws java.io.IOException { |
763 |
|
// Write out element count, and any hidden stuff |
764 |
|
s.defaultWriteObject(); |
765 |
|
|
766 |
< |
// Write out array length |
767 |
< |
// For compatibility with 1.5 version, must be at least 2. |
673 |
< |
s.writeInt(Math.max(2, queue.length)); |
766 |
> |
// Write out array length, for compatibility with 1.5 version |
767 |
> |
s.writeInt(Math.max(2, size + 1)); |
768 |
|
|
769 |
< |
// Write out all elements in the proper order. |
770 |
< |
for (int i=0; i<size; i++) |
769 |
> |
// Write out all elements in the "proper order". |
770 |
> |
for (int i = 0; i < size; i++) |
771 |
|
s.writeObject(queue[i]); |
772 |
|
} |
773 |
|
|
774 |
|
/** |
775 |
< |
* Reconstitute the <tt>PriorityQueue</tt> instance from a stream |
776 |
< |
* (that is, deserialize it). |
775 |
> |
* Reconstitutes the {@code PriorityQueue} instance from a stream |
776 |
> |
* (that is, deserializes it). |
777 |
> |
* |
778 |
|
* @param s the stream |
779 |
+ |
* @throws ClassNotFoundException if the class of a serialized object |
780 |
+ |
* could not be found |
781 |
+ |
* @throws java.io.IOException if an I/O error occurs |
782 |
|
*/ |
783 |
|
private void readObject(java.io.ObjectInputStream s) |
784 |
|
throws java.io.IOException, ClassNotFoundException { |
785 |
|
// Read in size, and any hidden stuff |
786 |
|
s.defaultReadObject(); |
787 |
|
|
788 |
< |
// Read in array length and allocate array |
789 |
< |
int arrayLength = s.readInt(); |
790 |
< |
queue = new Object[arrayLength]; |
791 |
< |
|
792 |
< |
// Read in all elements in the proper order. |
793 |
< |
for (int i=0; i<size; i++) |
794 |
< |
queue[i] = (E) s.readObject(); |
788 |
> |
// Read in (and discard) array length |
789 |
> |
s.readInt(); |
790 |
> |
|
791 |
> |
queue = new Object[size]; |
792 |
> |
|
793 |
> |
// Read in all elements. |
794 |
> |
for (int i = 0; i < size; i++) |
795 |
> |
queue[i] = s.readObject(); |
796 |
> |
|
797 |
> |
// Elements are guaranteed to be in "proper order", but the |
798 |
> |
// spec has never explained what that might be. |
799 |
> |
heapify(); |
800 |
|
} |
801 |
|
|
802 |
+ |
/** |
803 |
+ |
* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em> |
804 |
+ |
* and <em>fail-fast</em> {@link Spliterator} over the elements in this |
805 |
+ |
* queue. |
806 |
+ |
* |
807 |
+ |
* <p>The {@code Spliterator} reports {@link Spliterator#SIZED}, |
808 |
+ |
* {@link Spliterator#SUBSIZED}, and {@link Spliterator#NONNULL}. |
809 |
+ |
* Overriding implementations should document the reporting of additional |
810 |
+ |
* characteristic values. |
811 |
+ |
* |
812 |
+ |
* @return a {@code Spliterator} over the elements in this queue |
813 |
+ |
* @since 1.8 |
814 |
+ |
*/ |
815 |
+ |
public final Spliterator<E> spliterator() { |
816 |
+ |
return new PriorityQueueSpliterator<>(this, 0, -1, 0); |
817 |
+ |
} |
818 |
+ |
|
819 |
+ |
static final class PriorityQueueSpliterator<E> implements Spliterator<E> { |
820 |
+ |
/* |
821 |
+ |
* This is very similar to ArrayList Spliterator, except for |
822 |
+ |
* extra null checks. |
823 |
+ |
*/ |
824 |
+ |
private final PriorityQueue<E> pq; |
825 |
+ |
private int index; // current index, modified on advance/split |
826 |
+ |
private int fence; // -1 until first use |
827 |
+ |
private int expectedModCount; // initialized when fence set |
828 |
+ |
|
829 |
+ |
/** Creates new spliterator covering the given range. */ |
830 |
+ |
PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence, |
831 |
+ |
int expectedModCount) { |
832 |
+ |
this.pq = pq; |
833 |
+ |
this.index = origin; |
834 |
+ |
this.fence = fence; |
835 |
+ |
this.expectedModCount = expectedModCount; |
836 |
+ |
} |
837 |
+ |
|
838 |
+ |
private int getFence() { // initialize fence to size on first use |
839 |
+ |
int hi; |
840 |
+ |
if ((hi = fence) < 0) { |
841 |
+ |
expectedModCount = pq.modCount; |
842 |
+ |
hi = fence = pq.size; |
843 |
+ |
} |
844 |
+ |
return hi; |
845 |
+ |
} |
846 |
+ |
|
847 |
+ |
public PriorityQueueSpliterator<E> trySplit() { |
848 |
+ |
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; |
849 |
+ |
return (lo >= mid) ? null : |
850 |
+ |
new PriorityQueueSpliterator<>(pq, lo, index = mid, |
851 |
+ |
expectedModCount); |
852 |
+ |
} |
853 |
+ |
|
854 |
+ |
@SuppressWarnings("unchecked") |
855 |
+ |
public void forEachRemaining(Consumer<? super E> action) { |
856 |
+ |
int i, hi, mc; // hoist accesses and checks from loop |
857 |
+ |
PriorityQueue<E> q; Object[] a; |
858 |
+ |
if (action == null) |
859 |
+ |
throw new NullPointerException(); |
860 |
+ |
if ((q = pq) != null && (a = q.queue) != null) { |
861 |
+ |
if ((hi = fence) < 0) { |
862 |
+ |
mc = q.modCount; |
863 |
+ |
hi = q.size; |
864 |
+ |
} |
865 |
+ |
else |
866 |
+ |
mc = expectedModCount; |
867 |
+ |
if ((i = index) >= 0 && (index = hi) <= a.length) { |
868 |
+ |
for (E e;; ++i) { |
869 |
+ |
if (i < hi) { |
870 |
+ |
if ((e = (E) a[i]) == null) // must be CME |
871 |
+ |
break; |
872 |
+ |
action.accept(e); |
873 |
+ |
} |
874 |
+ |
else if (q.modCount != mc) |
875 |
+ |
break; |
876 |
+ |
else |
877 |
+ |
return; |
878 |
+ |
} |
879 |
+ |
} |
880 |
+ |
} |
881 |
+ |
throw new ConcurrentModificationException(); |
882 |
+ |
} |
883 |
+ |
|
884 |
+ |
public boolean tryAdvance(Consumer<? super E> action) { |
885 |
+ |
if (action == null) |
886 |
+ |
throw new NullPointerException(); |
887 |
+ |
int hi = getFence(), lo = index; |
888 |
+ |
if (lo >= 0 && lo < hi) { |
889 |
+ |
index = lo + 1; |
890 |
+ |
@SuppressWarnings("unchecked") E e = (E)pq.queue[lo]; |
891 |
+ |
if (e == null) |
892 |
+ |
throw new ConcurrentModificationException(); |
893 |
+ |
action.accept(e); |
894 |
+ |
if (pq.modCount != expectedModCount) |
895 |
+ |
throw new ConcurrentModificationException(); |
896 |
+ |
return true; |
897 |
+ |
} |
898 |
+ |
return false; |
899 |
+ |
} |
900 |
+ |
|
901 |
+ |
public long estimateSize() { |
902 |
+ |
return (long) (getFence() - index); |
903 |
+ |
} |
904 |
+ |
|
905 |
+ |
public int characteristics() { |
906 |
+ |
return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL; |
907 |
+ |
} |
908 |
+ |
} |
909 |
|
} |