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/* |
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* %W% %E% |
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* |
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* Copyright 2003 Sun Microsystems, Inc. All rights reserved. |
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* Copyright 2004 Sun Microsystems, Inc. All rights reserved. |
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* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. |
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*/ |
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* <i>natural order</i> (see {@link Comparable}), or according to a |
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* {@link java.util.Comparator}, depending on which constructor is |
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* used. A priority queue does not permit <tt>null</tt> elements. |
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* A priority queue relying on natural ordering also does not |
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* permit insertion of non-comparable objects (doing so may result |
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* in <tt>ClassCastException</tt>). |
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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 {@link #remove()} and {@link #poll()} |
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* methods remove and return the head of the queue, and the {@link |
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* #element()} and {@link #peek()} methods return, but do not delete, |
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* the head of the queue. |
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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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* 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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* 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 implements all of the <em>optional</em> methods of |
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* the {@link Collection} and {@link Iterator} interfaces. The |
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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. |
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* The |
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* 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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* @since 1.5 |
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* @version %I%, %G% |
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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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*/ |
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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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private static final long serialVersionUID = -7720805057305804111L; |
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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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SortedSet<? extends E> s = (SortedSet<? extends E>)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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/** |
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* Inserts the specified element to this priority queue. |
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* Inserts the specified element into this priority queue. |
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* |
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* @return <tt>true</tt> |
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* @throws ClassCastException if the specified element cannot be compared |
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return offer(o); |
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} |
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– |
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/** |
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* Adds all of the elements in the specified collection to this queue. |
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* The behavior of this operation is undefined if |
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* the specified collection is modified while the operation is in |
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* progress. (This implies that the behavior of this call is undefined if |
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* the specified collection is this queue, and this queue is nonempty.) |
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* <p> |
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* This implementation iterates over the specified collection, and adds |
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* each object returned by the iterator to this collection, in turn. |
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* @param c collection whose elements are to be added to this queue |
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* @return <tt>true</tt> if this queue changed as a result of the |
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* call. |
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* @throws NullPointerException if <tt>c</tt> or any element in <tt>c</tt> |
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* is <tt>null</tt> |
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* @throws ClassCastException if any element cannot be compared |
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* with elements currently in the priority queue according |
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* to the priority queue's ordering. |
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* Removes a single instance of the specified element from this |
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* queue, if it is present. |
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*/ |
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public boolean addAll(Collection<? extends E> c) { |
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return super.addAll(c); |
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} |
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public boolean remove(Object o) { |
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if (o == null) |
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return false; |
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} |
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/** |
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* Remove all elements from the priority queue. |
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* Removes all elements from the priority queue. |
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* The queue will be empty after this call returns. |
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*/ |
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public void clear() { |
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modCount++; |