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package java.util; |
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/* |
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* Copyright 2003-2006 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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* 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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/** |
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* An unbounded priority {@linkplain Queue queue} based on a priority heap. |
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* This queue orders |
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* elements according to an order specified at construction time, which is |
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* specified in the same manner as {@link java.util.TreeSet} and |
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* {@link java.util.TreeMap}: elements are ordered |
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* either according to their <i>natural order</i> (see {@link Comparable}), or |
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* according to a {@link java.util.Comparator}, depending on which |
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* constructor is used. |
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* <p>The <em>head</em> of this queue is the <em>least</em> element with |
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* respect to the specified ordering. |
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* If multiple elements are tied for least value, the |
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* head is one of those elements. A priority queue does not permit |
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* <tt>null</tt> elements. |
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* |
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* <p>The {@link #remove()} and {@link #poll()} methods remove and |
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* return the head of the queue. |
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* |
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* <p>The {@link #element()} and {@link #peek()} methods return, but do |
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* not delete, the head of the queue. |
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* |
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* <p>A priority queue has a <i>capacity</i>. The capacity is the |
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* size of the array used internally to store the elements on the |
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* queue. |
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* It is always at least as large as the queue size. As |
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* elements are added to a priority queue, its capacity grows |
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* automatically. The details of the growth policy are not specified. |
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* |
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* <p>The Iterator provided in method {@link #iterator()} is <em>not</em> |
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* guaranteed to traverse the elements of the PriorityQueue in any |
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* particular order. If you need ordered traversal, consider using |
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* <tt>Arrays.sort(pq.toArray())</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 {@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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* <i>capacity</i> governing the size of an array used to store the |
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* elements on the queue. It is always at least as large as the queue |
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* size. As elements are added to a priority queue, its capacity |
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* grows automatically. The details of the growth policy are not |
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* specified. |
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* |
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* <p>This class and its iterator implement all of the |
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* <em>optional</em> methods of the {@link Collection} and {@link |
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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 {@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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* java.util.concurrent.BlockingPriorityQueue} class. |
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* |
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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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* 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 |
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* O(log(n)) time for the enqueing and dequeing 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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* @author Josh Bloch |
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* @version %I%, %G% |
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* @author Josh Bloch, Doug Lea |
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* @param <E> the type of elements held in this collection |
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*/ |
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public class PriorityQueue<E> extends AbstractQueue<E> |
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implements Queue<E>, java.io.Serializable { |
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implements java.io.Serializable { |
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|
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private static final long serialVersionUID = -7720805057305804111L; |
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|
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private static final int DEFAULT_INITIAL_CAPACITY = 11; |
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|
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/** |
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* Priority queue represented as a balanced binary heap: the two children |
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* of queue[n] are queue[2*n] and queue[2*n + 1]. The priority queue is |
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* ordered by comparator, or by the elements' natural ordering, if |
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* comparator is null: For each node n in the heap and each descendant d |
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* of n, n <= d. |
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* |
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* The element with the lowest value is in queue[1], assuming the queue is |
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* nonempty. (A one-based array is used in preference to the traditional |
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* zero-based array to simplify parent and child calculations.) |
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* |
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* queue.length must be >= 2, even if size == 0. |
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* Priority queue represented as a balanced binary heap: the two |
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* children of queue[n] are queue[2*n+1] and queue[2*(n+1)]. The |
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* priority queue is ordered by comparator, or by the elements' |
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* natural ordering, if comparator is null: For each node n in the |
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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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|
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private transient int modCount = 0; |
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|
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/** |
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* Creates a <tt>PriorityQueue</tt> with the default initial capacity |
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* (11) that orders its elements according to their natural |
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* ordering (using <tt>Comparable</tt>). |
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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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public PriorityQueue() { |
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this(DEFAULT_INITIAL_CAPACITY, 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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* that orders its elements according to their natural ordering |
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* (using <tt>Comparable</tt>). |
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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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* 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 {@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 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 used to order this priority queue. |
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* If <tt>null</tt> then the order depends on the elements' natural |
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* ordering. |
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* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less |
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* than 1 |
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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 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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public PriorityQueue(int initialCapacity, |
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Comparator<? super E> comparator) { |
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// Note: This restriction of at least one is not actually needed, |
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// but continues for 1.5 compatibility |
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if (initialCapacity < 1) |
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throw new IllegalArgumentException(); |
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this.queue = new Object[initialCapacity + 1]; |
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this.queue = new Object[initialCapacity]; |
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this.comparator = comparator; |
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} |
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|
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/** |
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* Common code to initialize underlying queue array across |
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* constructors below. |
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*/ |
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private void initializeArray(Collection<? extends E> c) { |
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int sz = c.size(); |
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int initialCapacity = (int)Math.min((sz * 110L) / 100, |
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Integer.MAX_VALUE - 1); |
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if (initialCapacity < 1) |
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initialCapacity = 1; |
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|
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this.queue = new Object[initialCapacity + 1]; |
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} |
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|
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/** |
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* Initially fill elements of the queue array under the |
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* knowledge that it is sorted or is another PQ, in which |
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* case we can just place the elements without fixups. |
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*/ |
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private void fillFromSorted(Collection<? extends E> c) { |
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for (Iterator<? extends E> i = c.iterator(); i.hasNext(); ) |
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queue[++size] = i.next(); |
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} |
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|
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|
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/** |
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* Initially fill elements of the queue array that is |
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* not to our knowledge sorted, so we must add them |
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* one by one. |
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*/ |
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private void fillFromUnsorted(Collection<? extends E> c) { |
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for (Iterator<? extends E> i = c.iterator(); i.hasNext(); ) |
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add(i.next()); |
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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. The priority queue has an initial |
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* capacity of 110% of the size of the specified collection or 1 |
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* if the collection is empty. 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 sorted |
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* according to the same comparator, or according to its elements' |
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* natural order if the collection is sorted according to its |
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* elements' natural order. Otherwise, the priority queue is |
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* ordered according to its elements' natural order. |
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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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* @param c the collection whose elements are to be placed |
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* into this priority queue |
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* @throws ClassCastException if elements of the specified collection |
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* cannot be compared to one another according to the priority |
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* queue's ordering. |
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* @throws NullPointerException if <tt>c</tt> or any element within it |
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* is <tt>null</tt> |
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* queue's ordering |
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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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public PriorityQueue(Collection<? extends E> c) { |
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initializeArray(c); |
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if (c instanceof SortedSet) { |
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// @fixme double-cast workaround for compiler |
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SortedSet<? extends E> s = (SortedSet<? extends E>) (SortedSet)c; |
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comparator = (Comparator<? super E>)s.comparator(); |
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fillFromSorted(s); |
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< |
} else if (c instanceof PriorityQueue) { |
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PriorityQueue<? extends E> s = (PriorityQueue<? extends E>) c; |
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comparator = (Comparator<? super E>)s.comparator(); |
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fillFromSorted(s); |
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} else { |
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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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else { |
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comparator = null; |
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< |
fillFromUnsorted(c); |
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> |
heapify(); |
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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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* specified collection. The priority queue has an initial |
191 |
< |
* capacity of 110% of the size of the specified collection or 1 |
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* if the collection is empty. This priority queue will be sorted |
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* according to the same comparator as the given collection, or |
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< |
* according to its elements' natural order if the collection is |
195 |
< |
* sorted according to its elements' natural order. |
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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. |
199 |
< |
* @throws ClassCastException if elements of the specified collection |
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* cannot be compared to one another according to the priority |
219 |
< |
* queue's ordering. |
220 |
< |
* @throws NullPointerException if <tt>c</tt> or any element within it |
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< |
* is <tt>null</tt> |
189 |
> |
* Creates a {@code PriorityQueue} containing the elements in the |
190 |
> |
* specified priority queue. This priority queue will be |
191 |
> |
* ordered according to the same ordering as the given priority |
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> |
* queue. |
193 |
> |
* |
194 |
> |
* @param c the priority queue whose elements are to be placed |
195 |
> |
* into this priority queue |
196 |
> |
* @throws ClassCastException if elements of {@code c} cannot be |
197 |
> |
* compared to one another according to {@code c}'s |
198 |
> |
* ordering |
199 |
> |
* @throws NullPointerException if the specified priority queue or any |
200 |
> |
* of its elements are null |
201 |
|
*/ |
202 |
|
public PriorityQueue(PriorityQueue<? extends E> c) { |
224 |
– |
initializeArray(c); |
203 |
|
comparator = (Comparator<? super E>)c.comparator(); |
204 |
< |
fillFromSorted(c); |
204 |
> |
initFromCollection(c); |
205 |
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} |
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|
|
207 |
|
/** |
208 |
< |
* Creates a <tt>PriorityQueue</tt> containing the elements in the |
209 |
< |
* specified collection. The priority queue has an initial |
210 |
< |
* capacity of 110% of the size of the specified collection or 1 |
233 |
< |
* if the collection is empty. This priority queue will be sorted |
234 |
< |
* according to the same comparator as the given collection, or |
235 |
< |
* according to its elements' natural order if the collection is |
236 |
< |
* sorted according to its elements' natural order. |
208 |
> |
* Creates a {@code PriorityQueue} containing the elements in the |
209 |
> |
* specified sorted set. This priority queue will be ordered |
210 |
> |
* according to the same ordering as the given sorted set. |
211 |
|
* |
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< |
* @param c the collection whose elements are to be placed |
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< |
* into this priority queue. |
214 |
< |
* @throws ClassCastException if elements of the specified collection |
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< |
* cannot be compared to one another according to the priority |
216 |
< |
* queue's ordering. |
217 |
< |
* @throws NullPointerException if <tt>c</tt> or any element within it |
218 |
< |
* is <tt>null</tt> |
212 |
> |
* @param c the sorted set whose elements are to be placed |
213 |
> |
* into this priority queue |
214 |
> |
* @throws ClassCastException if elements of the specified sorted |
215 |
> |
* set cannot be compared to one another according to the |
216 |
> |
* sorted set's ordering |
217 |
> |
* @throws NullPointerException if the specified sorted set or any |
218 |
> |
* of its elements are null |
219 |
|
*/ |
220 |
|
public PriorityQueue(SortedSet<? extends E> c) { |
247 |
– |
initializeArray(c); |
221 |
|
comparator = (Comparator<? super E>)c.comparator(); |
222 |
< |
fillFromSorted(c); |
222 |
> |
initFromCollection(c); |
223 |
|
} |
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|
|
225 |
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/** |
226 |
< |
* Resize array, if necessary, to be able to hold given index |
226 |
> |
* Initializes queue array with elements from the given Collection. |
227 |
> |
* |
228 |
> |
* @param c the collection |
229 |
|
*/ |
230 |
< |
private void grow(int index) { |
231 |
< |
int newlen = queue.length; |
232 |
< |
if (index < newlen) // don't need to grow |
233 |
< |
return; |
234 |
< |
if (index == Integer.MAX_VALUE) |
235 |
< |
throw new OutOfMemoryError(); |
236 |
< |
while (newlen <= index) { |
262 |
< |
if (newlen >= Integer.MAX_VALUE / 2) // avoid overflow |
263 |
< |
newlen = Integer.MAX_VALUE; |
264 |
< |
else |
265 |
< |
newlen <<= 2; |
266 |
< |
} |
267 |
< |
Object[] newQueue = new Object[newlen]; |
268 |
< |
System.arraycopy(queue, 0, newQueue, 0, queue.length); |
269 |
< |
queue = newQueue; |
230 |
> |
private void initFromCollection(Collection<? extends E> c) { |
231 |
> |
Object[] a = c.toArray(); |
232 |
> |
// If c.toArray incorrectly doesn't return Object[], copy it. |
233 |
> |
if (a.getClass() != Object[].class) |
234 |
> |
a = Arrays.copyOf(a, a.length, Object[].class); |
235 |
> |
queue = a; |
236 |
> |
size = a.length; |
237 |
|
} |
271 |
– |
|
272 |
– |
// Queue Methods |
238 |
|
|
239 |
+ |
/** |
240 |
+ |
* Increases the capacity of the array. |
241 |
+ |
* |
242 |
+ |
* @param minCapacity the desired minimum capacity |
243 |
+ |
*/ |
244 |
+ |
private void grow(int minCapacity) { |
245 |
+ |
if (minCapacity < 0) // overflow |
246 |
+ |
throw new OutOfMemoryError(); |
247 |
+ |
int oldCapacity = queue.length; |
248 |
+ |
// Double size if small; else grow by 50% |
249 |
+ |
int newCapacity = ((oldCapacity < 64)? |
250 |
+ |
((oldCapacity + 1) * 2): |
251 |
+ |
((oldCapacity / 2) * 3)); |
252 |
+ |
if (newCapacity < 0) // overflow |
253 |
+ |
newCapacity = Integer.MAX_VALUE; |
254 |
+ |
if (newCapacity < minCapacity) |
255 |
+ |
newCapacity = minCapacity; |
256 |
+ |
queue = Arrays.copyOf(queue, newCapacity); |
257 |
+ |
} |
258 |
|
|
259 |
+ |
/** |
260 |
+ |
* Inserts the specified element into this priority queue. |
261 |
+ |
* |
262 |
+ |
* @return {@code true} (as specified by {@link Collection#add}) |
263 |
+ |
* @throws ClassCastException if the specified element cannot be |
264 |
+ |
* compared with elements currently in this priority queue |
265 |
+ |
* according to the priority queue's ordering |
266 |
+ |
* @throws NullPointerException if the specified element is null |
267 |
+ |
*/ |
268 |
+ |
public boolean add(E e) { |
269 |
+ |
return offer(e); |
270 |
+ |
} |
271 |
|
|
272 |
|
/** |
273 |
< |
* Add the specified element to this priority queue. |
273 |
> |
* Inserts the specified element into this priority queue. |
274 |
|
* |
275 |
< |
* @return <tt>true</tt> |
276 |
< |
* @throws ClassCastException if the specified element cannot be compared |
277 |
< |
* with elements currently in the priority queue according |
278 |
< |
* to the priority queue's ordering. |
279 |
< |
* @throws NullPointerException if the specified element is <tt>null</tt>. |
275 |
> |
* @return {@code true} (as specified by {@link Queue#offer}) |
276 |
> |
* @throws ClassCastException if the specified element cannot be |
277 |
> |
* compared with elements currently in this priority queue |
278 |
> |
* according to the priority queue's ordering |
279 |
> |
* @throws NullPointerException if the specified element is null |
280 |
|
*/ |
281 |
< |
public boolean offer(E o) { |
282 |
< |
if (o == null) |
281 |
> |
public boolean offer(E e) { |
282 |
> |
if (e == null) |
283 |
|
throw new NullPointerException(); |
284 |
|
modCount++; |
285 |
< |
++size; |
286 |
< |
|
287 |
< |
// Grow backing store if necessary |
288 |
< |
if (size >= queue.length) |
289 |
< |
grow(size); |
290 |
< |
|
291 |
< |
queue[size] = o; |
292 |
< |
fixUp(size); |
285 |
> |
int i = size; |
286 |
> |
if (i >= queue.length) |
287 |
> |
grow(i + 1); |
288 |
> |
size = i + 1; |
289 |
> |
if (i == 0) |
290 |
> |
queue[0] = e; |
291 |
> |
else |
292 |
> |
siftUp(i, e); |
293 |
|
return true; |
294 |
|
} |
295 |
|
|
296 |
< |
public E poll() { |
296 |
> |
public E peek() { |
297 |
|
if (size == 0) |
298 |
|
return null; |
299 |
< |
return (E) remove(1); |
299 |
> |
return (E) queue[0]; |
300 |
|
} |
301 |
|
|
302 |
< |
public E peek() { |
303 |
< |
return (E) queue[1]; |
302 |
> |
private int indexOf(Object o) { |
303 |
> |
if (o != null) { |
304 |
> |
for (int i = 0; i < size; i++) |
305 |
> |
if (o.equals(queue[i])) |
306 |
> |
return i; |
307 |
> |
} |
308 |
> |
return -1; |
309 |
|
} |
310 |
|
|
310 |
– |
// Collection Methods - the first two override to update docs |
311 |
– |
|
311 |
|
/** |
312 |
< |
* Adds the specified element to this queue. |
313 |
< |
* @return <tt>true</tt> (as per the general contract of |
314 |
< |
* <tt>Collection.add</tt>). |
312 |
> |
* Removes a single instance of the specified element from this queue, |
313 |
> |
* if it is present. More formally, removes an element {@code e} such |
314 |
> |
* that {@code o.equals(e)}, if this queue contains one or more such |
315 |
> |
* elements. Returns {@code true} if and only if this queue contained |
316 |
> |
* the specified element (or equivalently, if this queue changed as a |
317 |
> |
* result of the call). |
318 |
|
* |
319 |
< |
* @throws NullPointerException {@inheritDoc} |
320 |
< |
* @throws ClassCastException if the specified element cannot be compared |
319 |
< |
* with elements currently in the priority queue according |
320 |
< |
* to the priority queue's ordering. |
319 |
> |
* @param o element to be removed from this queue, if present |
320 |
> |
* @return {@code true} if this queue changed as a result of the call |
321 |
|
*/ |
322 |
< |
public boolean add(E o) { |
323 |
< |
return super.add(o); |
322 |
> |
public boolean remove(Object o) { |
323 |
> |
int i = indexOf(o); |
324 |
> |
if (i == -1) |
325 |
> |
return false; |
326 |
> |
else { |
327 |
> |
removeAt(i); |
328 |
> |
return true; |
329 |
> |
} |
330 |
|
} |
331 |
|
|
326 |
– |
|
332 |
|
/** |
333 |
< |
* Adds all of the elements in the specified collection to this queue. |
334 |
< |
* The behavior of this operation is undefined if |
335 |
< |
* the specified collection is modified while the operation is in |
336 |
< |
* progress. (This implies that the behavior of this call is undefined if |
337 |
< |
* the specified collection is this queue, and this queue is nonempty.) |
338 |
< |
* <p> |
339 |
< |
* This implementation iterates over the specified collection, and adds |
340 |
< |
* each object returned by the iterator to this collection, in turn. |
341 |
< |
* @throws NullPointerException {@inheritDoc} |
342 |
< |
* @throws ClassCastException if any element cannot be compared |
343 |
< |
* with elements currently in the priority queue according |
344 |
< |
* to the priority queue's ordering. |
345 |
< |
*/ |
346 |
< |
public boolean addAll(Collection<? extends E> c) { |
342 |
< |
return super.addAll(c); |
333 |
> |
* Version of remove using reference equality, not equals. |
334 |
> |
* Needed by iterator.remove. |
335 |
> |
* |
336 |
> |
* @param o element to be removed from this queue, if present |
337 |
> |
* @return {@code true} if removed |
338 |
> |
*/ |
339 |
> |
boolean removeEq(Object o) { |
340 |
> |
for (int i = 0; i < size; i++) { |
341 |
> |
if (o == queue[i]) { |
342 |
> |
removeAt(i); |
343 |
> |
return true; |
344 |
> |
} |
345 |
> |
} |
346 |
> |
return false; |
347 |
|
} |
348 |
|
|
349 |
+ |
/** |
350 |
+ |
* Returns {@code true} if this queue contains the specified element. |
351 |
+ |
* More formally, returns {@code true} if and only if this queue contains |
352 |
+ |
* at least one element {@code e} such that {@code o.equals(e)}. |
353 |
+ |
* |
354 |
+ |
* @param o object to be checked for containment in this queue |
355 |
+ |
* @return {@code true} if this queue contains the specified element |
356 |
+ |
*/ |
357 |
+ |
public boolean contains(Object o) { |
358 |
+ |
return indexOf(o) != -1; |
359 |
+ |
} |
360 |
|
|
361 |
< |
/** |
362 |
< |
* Removes a single instance of the specified element from this |
363 |
< |
* queue, if it is present. More formally, |
349 |
< |
* removes an element <tt>e</tt> such that <tt>(o==null ? e==null : |
350 |
< |
* o.equals(e))</tt>, if the queue contains one or more such |
351 |
< |
* elements. Returns <tt>true</tt> if the queue contained the |
352 |
< |
* specified element (or equivalently, if the queue changed as a |
353 |
< |
* result of the call). |
361 |
> |
/** |
362 |
> |
* Returns an array containing all of the elements in this queue. |
363 |
> |
* The elements are in no particular order. |
364 |
|
* |
365 |
< |
* <p>This implementation iterates over the queue looking for the |
366 |
< |
* specified element. If it finds the element, it removes the element |
367 |
< |
* from the queue using the iterator's remove method.<p> |
365 |
> |
* <p>The returned array will be "safe" in that no references to it are |
366 |
> |
* maintained by this queue. (In other words, this method must allocate |
367 |
> |
* a new array). The caller is thus free to modify the returned array. |
368 |
|
* |
369 |
+ |
* <p>This method acts as bridge between array-based and collection-based |
370 |
+ |
* APIs. |
371 |
+ |
* |
372 |
+ |
* @return an array containing all of the elements in this queue |
373 |
|
*/ |
374 |
< |
public boolean remove(Object o) { |
375 |
< |
if (o == null) |
376 |
< |
return false; |
374 |
> |
public Object[] toArray() { |
375 |
> |
return Arrays.copyOf(queue, size); |
376 |
> |
} |
377 |
|
|
378 |
< |
if (comparator == null) { |
379 |
< |
for (int i = 1; i <= size; i++) { |
380 |
< |
if (((Comparable<E>)queue[i]).compareTo((E)o) == 0) { |
381 |
< |
remove(i); |
382 |
< |
return true; |
383 |
< |
} |
384 |
< |
} |
385 |
< |
} else { |
386 |
< |
for (int i = 1; i <= size; i++) { |
387 |
< |
if (comparator.compare((E)queue[i], (E)o) == 0) { |
388 |
< |
remove(i); |
389 |
< |
return true; |
390 |
< |
} |
391 |
< |
} |
392 |
< |
} |
393 |
< |
return false; |
378 |
> |
/** |
379 |
> |
* Returns an array containing all of the elements in this queue; the |
380 |
> |
* runtime type of the returned array is that of the specified array. |
381 |
> |
* The returned array elements are in no particular order. |
382 |
> |
* If the queue fits in the specified array, it is returned therein. |
383 |
> |
* Otherwise, a new array is allocated with the runtime type of the |
384 |
> |
* specified array and the size of this queue. |
385 |
> |
* |
386 |
> |
* <p>If the queue fits in the specified array with room to spare |
387 |
> |
* (i.e., the array has more elements than the queue), the element in |
388 |
> |
* the array immediately following the end of the collection is set to |
389 |
> |
* {@code null}. |
390 |
> |
* |
391 |
> |
* <p>Like the {@link #toArray()} method, this method acts as bridge between |
392 |
> |
* array-based and collection-based APIs. Further, this method allows |
393 |
> |
* precise control over the runtime type of the output array, and may, |
394 |
> |
* under certain circumstances, be used to save allocation costs. |
395 |
> |
* |
396 |
> |
* <p>Suppose <tt>x</tt> is a queue known to contain only strings. |
397 |
> |
* The following code can be used to dump the queue into a newly |
398 |
> |
* allocated array of <tt>String</tt>: |
399 |
> |
* |
400 |
> |
* <pre> |
401 |
> |
* String[] y = x.toArray(new String[0]);</pre> |
402 |
> |
* |
403 |
> |
* Note that <tt>toArray(new Object[0])</tt> is identical in function to |
404 |
> |
* <tt>toArray()</tt>. |
405 |
> |
* |
406 |
> |
* @param a the array into which the elements of the queue are to |
407 |
> |
* be stored, if it is big enough; otherwise, a new array of the |
408 |
> |
* same runtime type is allocated for this purpose. |
409 |
> |
* @return an array containing all of the elements in this queue |
410 |
> |
* @throws ArrayStoreException if the runtime type of the specified array |
411 |
> |
* is not a supertype of the runtime type of every element in |
412 |
> |
* this queue |
413 |
> |
* @throws NullPointerException if the specified array is null |
414 |
> |
*/ |
415 |
> |
public <T> T[] toArray(T[] a) { |
416 |
> |
if (a.length < size) |
417 |
> |
// Make a new array of a's runtime type, but my contents: |
418 |
> |
return (T[]) Arrays.copyOf(queue, size, a.getClass()); |
419 |
> |
System.arraycopy(queue, 0, a, 0, size); |
420 |
> |
if (a.length > size) |
421 |
> |
a[size] = null; |
422 |
> |
return a; |
423 |
|
} |
424 |
|
|
425 |
|
/** |
426 |
|
* Returns an iterator over the elements in this queue. The iterator |
427 |
|
* does not return the elements in any particular order. |
428 |
|
* |
429 |
< |
* @return an iterator over the elements in this queue. |
429 |
> |
* @return an iterator over the elements in this queue |
430 |
|
*/ |
431 |
|
public Iterator<E> iterator() { |
432 |
|
return new Itr(); |
433 |
|
} |
434 |
|
|
435 |
< |
private class Itr implements Iterator<E> { |
435 |
> |
private final class Itr implements Iterator<E> { |
436 |
|
/** |
437 |
|
* Index (into queue array) of element to be returned by |
438 |
|
* subsequent call to next. |
439 |
|
*/ |
440 |
< |
private int cursor = 1; |
440 |
> |
private int cursor = 0; |
441 |
|
|
442 |
|
/** |
443 |
< |
* Index of element returned by most recent call to next or |
444 |
< |
* previous. Reset to 0 if this element is deleted by a call |
445 |
< |
* to remove. |
443 |
> |
* Index of element returned by most recent call to next, |
444 |
> |
* unless that element came from the forgetMeNot list. |
445 |
> |
* Set to -1 if element is deleted by a call to remove. |
446 |
|
*/ |
447 |
< |
private int lastRet = 0; |
447 |
> |
private int lastRet = -1; |
448 |
> |
|
449 |
> |
/** |
450 |
> |
* A queue of elements that were moved from the unvisited portion of |
451 |
> |
* the heap into the visited portion as a result of "unlucky" element |
452 |
> |
* removals during the iteration. (Unlucky element removals are those |
453 |
> |
* that require a siftup instead of a siftdown.) We must visit all of |
454 |
> |
* the elements in this list to complete the iteration. We do this |
455 |
> |
* after we've completed the "normal" iteration. |
456 |
> |
* |
457 |
> |
* We expect that most iterations, even those involving removals, |
458 |
> |
* will not need to store elements in this field. |
459 |
> |
*/ |
460 |
> |
private ArrayDeque<E> forgetMeNot = null; |
461 |
> |
|
462 |
> |
/** |
463 |
> |
* Element returned by the most recent call to next iff that |
464 |
> |
* element was drawn from the forgetMeNot list. |
465 |
> |
*/ |
466 |
> |
private E lastRetElt = null; |
467 |
|
|
468 |
|
/** |
469 |
|
* The modCount value that the iterator believes that the backing |
470 |
< |
* List should have. If this expectation is violated, the iterator |
470 |
> |
* Queue should have. If this expectation is violated, the iterator |
471 |
|
* has detected concurrent modification. |
472 |
|
*/ |
473 |
|
private int expectedModCount = modCount; |
474 |
|
|
475 |
|
public boolean hasNext() { |
476 |
< |
return cursor <= size; |
476 |
> |
return cursor < size || |
477 |
> |
(forgetMeNot != null && !forgetMeNot.isEmpty()); |
478 |
|
} |
479 |
|
|
480 |
|
public E next() { |
481 |
< |
checkForComodification(); |
482 |
< |
if (cursor > size) |
483 |
< |
throw new NoSuchElementException(); |
484 |
< |
E result = (E) queue[cursor]; |
485 |
< |
lastRet = cursor++; |
486 |
< |
return result; |
481 |
> |
if (expectedModCount != modCount) |
482 |
> |
throw new ConcurrentModificationException(); |
483 |
> |
if (cursor < size) |
484 |
> |
return (E) queue[lastRet = cursor++]; |
485 |
> |
if (forgetMeNot != null) { |
486 |
> |
lastRet = -1; |
487 |
> |
lastRetElt = forgetMeNot.poll(); |
488 |
> |
if (lastRetElt != null) |
489 |
> |
return lastRetElt; |
490 |
> |
} |
491 |
> |
throw new NoSuchElementException(); |
492 |
|
} |
493 |
|
|
494 |
|
public void remove() { |
495 |
< |
if (lastRet == 0) |
495 |
> |
if (expectedModCount != modCount) |
496 |
> |
throw new ConcurrentModificationException(); |
497 |
> |
if (lastRet != -1) { |
498 |
> |
E moved = PriorityQueue.this.removeAt(lastRet); |
499 |
> |
lastRet = -1; |
500 |
> |
if (moved == null) |
501 |
> |
cursor--; |
502 |
> |
else { |
503 |
> |
if (forgetMeNot == null) |
504 |
> |
forgetMeNot = new ArrayDeque<E>(); |
505 |
> |
forgetMeNot.add(moved); |
506 |
> |
} |
507 |
> |
} else if (lastRetElt != null) { |
508 |
> |
PriorityQueue.this.removeEq(lastRetElt); |
509 |
> |
lastRetElt = null; |
510 |
> |
} else { |
511 |
|
throw new IllegalStateException(); |
512 |
< |
checkForComodification(); |
430 |
< |
|
431 |
< |
PriorityQueue.this.remove(lastRet); |
432 |
< |
if (lastRet < cursor) |
433 |
< |
cursor--; |
434 |
< |
lastRet = 0; |
512 |
> |
} |
513 |
|
expectedModCount = modCount; |
514 |
|
} |
437 |
– |
|
438 |
– |
final void checkForComodification() { |
439 |
– |
if (modCount != expectedModCount) |
440 |
– |
throw new ConcurrentModificationException(); |
441 |
– |
} |
515 |
|
} |
516 |
|
|
517 |
|
public int size() { |
519 |
|
} |
520 |
|
|
521 |
|
/** |
522 |
< |
* Remove all elements from the priority queue. |
522 |
> |
* Removes all of the elements from this priority queue. |
523 |
> |
* The queue will be empty after this call returns. |
524 |
|
*/ |
525 |
|
public void clear() { |
526 |
|
modCount++; |
527 |
< |
|
454 |
< |
// Null out element references to prevent memory leak |
455 |
< |
for (int i=1; i<=size; i++) |
527 |
> |
for (int i = 0; i < size; i++) |
528 |
|
queue[i] = null; |
457 |
– |
|
529 |
|
size = 0; |
530 |
|
} |
531 |
|
|
532 |
+ |
public E poll() { |
533 |
+ |
if (size == 0) |
534 |
+ |
return null; |
535 |
+ |
int s = --size; |
536 |
+ |
modCount++; |
537 |
+ |
E result = (E) queue[0]; |
538 |
+ |
E x = (E) queue[s]; |
539 |
+ |
queue[s] = null; |
540 |
+ |
if (s != 0) |
541 |
+ |
siftDown(0, x); |
542 |
+ |
return result; |
543 |
+ |
} |
544 |
+ |
|
545 |
|
/** |
546 |
< |
* Removes and returns the ith element from queue. Recall |
463 |
< |
* that queue is one-based, so 1 <= i <= size. |
546 |
> |
* Removes the ith element from queue. |
547 |
|
* |
548 |
< |
* XXX: Could further special-case i==size, but is it worth it? |
549 |
< |
* XXX: Could special-case i==0, but is it worth it? |
548 |
> |
* Normally this method leaves the elements at up to i-1, |
549 |
> |
* inclusive, untouched. Under these circumstances, it returns |
550 |
> |
* null. Occasionally, in order to maintain the heap invariant, |
551 |
> |
* it must swap a later element of the list with one earlier than |
552 |
> |
* i. Under these circumstances, this method returns the element |
553 |
> |
* that was previously at the end of the list and is now at some |
554 |
> |
* position before i. This fact is used by iterator.remove so as to |
555 |
> |
* avoid missing traversing elements. |
556 |
|
*/ |
557 |
< |
private E remove(int i) { |
558 |
< |
assert i <= size; |
557 |
> |
private E removeAt(int i) { |
558 |
> |
assert i >= 0 && i < size; |
559 |
|
modCount++; |
560 |
< |
|
561 |
< |
E result = (E) queue[i]; |
562 |
< |
queue[i] = queue[size]; |
563 |
< |
queue[size--] = null; // Drop extra ref to prevent memory leak |
564 |
< |
if (i <= size) |
565 |
< |
fixDown(i); |
566 |
< |
return result; |
560 |
> |
int s = --size; |
561 |
> |
if (s == i) // removed last element |
562 |
> |
queue[i] = null; |
563 |
> |
else { |
564 |
> |
E moved = (E) queue[s]; |
565 |
> |
queue[s] = null; |
566 |
> |
siftDown(i, moved); |
567 |
> |
if (queue[i] == moved) { |
568 |
> |
siftUp(i, moved); |
569 |
> |
if (queue[i] != moved) |
570 |
> |
return moved; |
571 |
> |
} |
572 |
> |
} |
573 |
> |
return null; |
574 |
|
} |
575 |
|
|
576 |
|
/** |
577 |
< |
* Establishes the heap invariant (described above) assuming the heap |
578 |
< |
* satisfies the invariant except possibly for the leaf-node indexed by k |
579 |
< |
* (which may have a nextExecutionTime less than its parent's). |
580 |
< |
* |
581 |
< |
* This method functions by "promoting" queue[k] up the hierarchy |
582 |
< |
* (by swapping it with its parent) repeatedly until queue[k] |
583 |
< |
* is greater than or equal to its parent. |
584 |
< |
*/ |
585 |
< |
private void fixUp(int k) { |
586 |
< |
if (comparator == null) { |
587 |
< |
while (k > 1) { |
588 |
< |
int j = k >> 1; |
589 |
< |
if (((Comparable<E>)queue[j]).compareTo((E)queue[k]) <= 0) |
590 |
< |
break; |
591 |
< |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
592 |
< |
k = j; |
593 |
< |
} |
594 |
< |
} else { |
595 |
< |
while (k > 1) { |
596 |
< |
int j = k >> 1; |
597 |
< |
if (comparator.compare((E)queue[j], (E)queue[k]) <= 0) |
598 |
< |
break; |
599 |
< |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
600 |
< |
k = j; |
601 |
< |
} |
577 |
> |
* Inserts item x at position k, maintaining heap invariant by |
578 |
> |
* promoting x up the tree until it is greater than or equal to |
579 |
> |
* its parent, or is the root. |
580 |
> |
* |
581 |
> |
* To simplify and speed up coercions and comparisons. the |
582 |
> |
* Comparable and Comparator versions are separated into different |
583 |
> |
* methods that are otherwise identical. (Similarly for siftDown.) |
584 |
> |
* |
585 |
> |
* @param k the position to fill |
586 |
> |
* @param x the item to insert |
587 |
> |
*/ |
588 |
> |
private void siftUp(int k, E x) { |
589 |
> |
if (comparator != null) |
590 |
> |
siftUpUsingComparator(k, x); |
591 |
> |
else |
592 |
> |
siftUpComparable(k, x); |
593 |
> |
} |
594 |
> |
|
595 |
> |
private void siftUpComparable(int k, E x) { |
596 |
> |
Comparable<? super E> key = (Comparable<? super E>) x; |
597 |
> |
while (k > 0) { |
598 |
> |
int parent = (k - 1) >>> 1; |
599 |
> |
Object e = queue[parent]; |
600 |
> |
if (key.compareTo((E) e) >= 0) |
601 |
> |
break; |
602 |
> |
queue[k] = e; |
603 |
> |
k = parent; |
604 |
|
} |
605 |
+ |
queue[k] = key; |
606 |
+ |
} |
607 |
+ |
|
608 |
+ |
private void siftUpUsingComparator(int k, E x) { |
609 |
+ |
while (k > 0) { |
610 |
+ |
int parent = (k - 1) >>> 1; |
611 |
+ |
Object e = queue[parent]; |
612 |
+ |
if (comparator.compare(x, (E) e) >= 0) |
613 |
+ |
break; |
614 |
+ |
queue[k] = e; |
615 |
+ |
k = parent; |
616 |
+ |
} |
617 |
+ |
queue[k] = x; |
618 |
|
} |
619 |
|
|
620 |
|
/** |
621 |
< |
* Establishes the heap invariant (described above) in the subtree |
622 |
< |
* rooted at k, which is assumed to satisfy the heap invariant except |
623 |
< |
* possibly for node k itself (which may be greater than its children). |
624 |
< |
* |
625 |
< |
* This method functions by "demoting" queue[k] down the hierarchy |
626 |
< |
* (by swapping it with its smaller child) repeatedly until queue[k] |
627 |
< |
* is less than or equal to its children. |
628 |
< |
*/ |
629 |
< |
private void fixDown(int k) { |
630 |
< |
int j; |
631 |
< |
if (comparator == null) { |
632 |
< |
while ((j = k << 1) <= size) { |
633 |
< |
if (j<size && ((Comparable<E>)queue[j]).compareTo((E)queue[j+1]) > 0) |
634 |
< |
j++; // j indexes smallest kid |
635 |
< |
if (((Comparable<E>)queue[k]).compareTo((E)queue[j]) <= 0) |
636 |
< |
break; |
637 |
< |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
638 |
< |
k = j; |
639 |
< |
} |
640 |
< |
} else { |
641 |
< |
while ((j = k << 1) <= size) { |
642 |
< |
if (j < size && comparator.compare((E)queue[j], (E)queue[j+1]) > 0) |
643 |
< |
j++; // j indexes smallest kid |
644 |
< |
if (comparator.compare((E)queue[k], (E)queue[j]) <= 0) |
645 |
< |
break; |
646 |
< |
Object tmp = queue[j]; queue[j] = queue[k]; queue[k] = tmp; |
647 |
< |
k = j; |
648 |
< |
} |
621 |
> |
* Inserts item x at position k, maintaining heap invariant by |
622 |
> |
* demoting x down the tree repeatedly until it is less than or |
623 |
> |
* equal to its children or is a leaf. |
624 |
> |
* |
625 |
> |
* @param k the position to fill |
626 |
> |
* @param x the item to insert |
627 |
> |
*/ |
628 |
> |
private void siftDown(int k, E x) { |
629 |
> |
if (comparator != null) |
630 |
> |
siftDownUsingComparator(k, x); |
631 |
> |
else |
632 |
> |
siftDownComparable(k, x); |
633 |
> |
} |
634 |
> |
|
635 |
> |
private void siftDownComparable(int k, E x) { |
636 |
> |
Comparable<? super E> key = (Comparable<? super E>)x; |
637 |
> |
int half = size >>> 1; // loop while a non-leaf |
638 |
> |
while (k < half) { |
639 |
> |
int child = (k << 1) + 1; // assume left child is least |
640 |
> |
Object c = queue[child]; |
641 |
> |
int right = child + 1; |
642 |
> |
if (right < size && |
643 |
> |
((Comparable<? super E>) c).compareTo((E) queue[right]) > 0) |
644 |
> |
c = queue[child = right]; |
645 |
> |
if (key.compareTo((E) c) <= 0) |
646 |
> |
break; |
647 |
> |
queue[k] = c; |
648 |
> |
k = child; |
649 |
> |
} |
650 |
> |
queue[k] = key; |
651 |
> |
} |
652 |
> |
|
653 |
> |
private void siftDownUsingComparator(int k, E x) { |
654 |
> |
int half = size >>> 1; |
655 |
> |
while (k < half) { |
656 |
> |
int child = (k << 1) + 1; |
657 |
> |
Object c = queue[child]; |
658 |
> |
int right = child + 1; |
659 |
> |
if (right < size && |
660 |
> |
comparator.compare((E) c, (E) queue[right]) > 0) |
661 |
> |
c = queue[child = right]; |
662 |
> |
if (comparator.compare(x, (E) c) <= 0) |
663 |
> |
break; |
664 |
> |
queue[k] = c; |
665 |
> |
k = child; |
666 |
|
} |
667 |
+ |
queue[k] = x; |
668 |
|
} |
669 |
|
|
670 |
+ |
/** |
671 |
+ |
* Establishes the heap invariant (described above) in the entire tree, |
672 |
+ |
* assuming nothing about the order of the elements prior to the call. |
673 |
+ |
*/ |
674 |
+ |
private void heapify() { |
675 |
+ |
for (int i = (size >>> 1) - 1; i >= 0; i--) |
676 |
+ |
siftDown(i, (E) queue[i]); |
677 |
+ |
} |
678 |
|
|
679 |
|
/** |
680 |
< |
* Returns the comparator used to order this collection, or <tt>null</tt> |
681 |
< |
* if this collection is sorted according to its elements natural ordering |
682 |
< |
* (using <tt>Comparable</tt>). |
680 |
> |
* Returns the comparator used to order the elements in this |
681 |
> |
* queue, or {@code null} if this queue is sorted according to |
682 |
> |
* the {@linkplain Comparable natural ordering} of its elements. |
683 |
|
* |
684 |
< |
* @return the comparator used to order this collection, or <tt>null</tt> |
685 |
< |
* if this collection is sorted according to its elements natural ordering. |
684 |
> |
* @return the comparator used to order this queue, or |
685 |
> |
* {@code null} if this queue is sorted according to the |
686 |
> |
* natural ordering of its elements |
687 |
|
*/ |
688 |
|
public Comparator<? super E> comparator() { |
689 |
|
return comparator; |
690 |
|
} |
691 |
|
|
692 |
|
/** |
693 |
< |
* Save the state of the instance to a stream (that |
694 |
< |
* is, serialize it). |
693 |
> |
* Saves the state of the instance to a stream (that |
694 |
> |
* is, serializes it). |
695 |
|
* |
696 |
|
* @serialData The length of the array backing the instance is |
697 |
< |
* emitted (int), followed by all of its elements (each an |
698 |
< |
* <tt>Object</tt>) in the proper order. |
697 |
> |
* emitted (int), followed by all of its elements |
698 |
> |
* (each an {@code Object}) in the proper order. |
699 |
|
* @param s the stream |
700 |
|
*/ |
701 |
|
private void writeObject(java.io.ObjectOutputStream s) |
703 |
|
// Write out element count, and any hidden stuff |
704 |
|
s.defaultWriteObject(); |
705 |
|
|
706 |
< |
// Write out array length |
707 |
< |
s.writeInt(queue.length); |
706 |
> |
// Write out array length, for compatibility with 1.5 version |
707 |
> |
s.writeInt(Math.max(2, size + 1)); |
708 |
|
|
709 |
< |
// Write out all elements in the proper order. |
710 |
< |
for (int i=0; i<size; i++) |
709 |
> |
// Write out all elements in the "proper order". |
710 |
> |
for (int i = 0; i < size; i++) |
711 |
|
s.writeObject(queue[i]); |
712 |
|
} |
713 |
|
|
714 |
|
/** |
715 |
< |
* Reconstitute the <tt>ArrayList</tt> instance from a stream (that is, |
716 |
< |
* deserialize it). |
715 |
> |
* Reconstitutes the {@code PriorityQueue} instance from a stream |
716 |
> |
* (that is, deserializes it). |
717 |
> |
* |
718 |
|
* @param s the stream |
719 |
|
*/ |
720 |
|
private void readObject(java.io.ObjectInputStream s) |
722 |
|
// Read in size, and any hidden stuff |
723 |
|
s.defaultReadObject(); |
724 |
|
|
725 |
< |
// Read in array length and allocate array |
726 |
< |
int arrayLength = s.readInt(); |
588 |
< |
queue = new Object[arrayLength]; |
725 |
> |
// Read in (and discard) array length |
726 |
> |
s.readInt(); |
727 |
|
|
728 |
< |
// Read in all elements in the proper order. |
729 |
< |
for (int i=0; i<size; i++) |
728 |
> |
queue = new Object[size]; |
729 |
> |
|
730 |
> |
// Read in all elements. |
731 |
> |
for (int i = 0; i < size; i++) |
732 |
|
queue[i] = s.readObject(); |
593 |
– |
} |
733 |
|
|
734 |
+ |
// Elements are guaranteed to be in "proper order", but the |
735 |
+ |
// spec has never explained what that might be. |
736 |
+ |
heapify(); |
737 |
+ |
} |
738 |
|
} |
596 |
– |
|