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/* |
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* Copyright 2003-2006 Sun Microsystems, Inc. All Rights Reserved. |
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* Copyright (c) 2003, 2012, 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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* 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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* 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 Sun in the LICENSE file that accompanied this code. |
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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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* 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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* 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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|
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package java.util; |
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import java.util.stream.Stream; |
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import java.util.Spliterator; |
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import java.util.stream.Streams; |
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import java.util.function.Block; |
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|
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/** |
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* An unbounded priority {@linkplain Queue queue} based on a priority heap. |
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* Java Collections Framework</a>. |
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* |
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* @since 1.5 |
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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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* 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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* 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 = 0; // non-private to simplify nested class access |
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|
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/** |
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* Creates a {@code PriorityQueue} with the default initial |
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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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* @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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* @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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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. |
246 |
> |
if (a.getClass() != Object[].class) |
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> |
a = Arrays.copyOf(a, a.length, Object[].class); |
248 |
> |
int len = a.length; |
249 |
> |
if (len == 1 || this.comparator != null) |
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for (int i = 0; i < len; i++) |
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if (a[i] == 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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* @param c the collection |
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*/ |
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private void initFromCollection(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. |
233 |
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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; |
236 |
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size = a.length; |
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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 |
272 |
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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 |
287 |
> |
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 true; |
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} |
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|
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+ |
@SuppressWarnings("unchecked") |
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public E peek() { |
339 |
< |
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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* @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); |
364 |
< |
if (i == -1) |
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< |
return false; |
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< |
else { |
367 |
< |
removeAt(i); |
368 |
< |
return true; |
369 |
< |
} |
363 |
> |
int i = indexOf(o); |
364 |
> |
if (i == -1) |
365 |
> |
return false; |
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> |
else { |
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> |
removeAt(i); |
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> |
return true; |
369 |
> |
} |
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} |
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|
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/** |
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* @return {@code true} if removed |
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*/ |
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boolean removeEq(Object o) { |
380 |
< |
for (int i = 0; i < size; i++) { |
381 |
< |
if (o == queue[i]) { |
380 |
> |
for (int i = 0; i < size; i++) { |
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> |
if (o == queue[i]) { |
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removeAt(i); |
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return true; |
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} |
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* @return {@code true} if this queue contains the specified element |
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*/ |
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public boolean contains(Object o) { |
398 |
< |
return indexOf(o) != -1; |
398 |
> |
return indexOf(o) != -1; |
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} |
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|
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/** |
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* precise control over the runtime type of the output array, and may, |
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* under certain circumstances, be used to save allocation costs. |
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* |
436 |
< |
* <p>Suppose <tt>x</tt> is a queue known to contain only strings. |
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> |
* <p>Suppose {@code x} is a queue known to contain only strings. |
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* The following code can be used to dump the queue into a newly |
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* allocated array of <tt>String</tt>: |
438 |
> |
* allocated array of {@code String}: |
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* |
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< |
* <pre> |
401 |
< |
* String[] y = x.toArray(new String[0]);</pre> |
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> |
* <pre> {@code String[] y = x.toArray(new String[0]);}</pre> |
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* |
442 |
< |
* Note that <tt>toArray(new Object[0])</tt> is identical in function to |
443 |
< |
* <tt>toArray()</tt>. |
442 |
> |
* Note that {@code toArray(new Object[0])} is identical in function to |
443 |
> |
* {@code toArray()}. |
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* |
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* @param a the array into which the elements of the queue are to |
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* be stored, if it is big enough; otherwise, a new array of the |
455 |
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if (a.length < size) |
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// Make a new array of a's runtime type, but my contents: |
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return (T[]) Arrays.copyOf(queue, size, a.getClass()); |
458 |
< |
System.arraycopy(queue, 0, a, 0, size); |
458 |
> |
System.arraycopy(queue, 0, a, 0, size); |
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if (a.length > size) |
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a[size] = null; |
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return a; |
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(forgetMeNot != null && !forgetMeNot.isEmpty()); |
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} |
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|
|
519 |
+ |
@SuppressWarnings("unchecked") |
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public E next() { |
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if (expectedModCount != modCount) |
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throw new ConcurrentModificationException(); |
549 |
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lastRetElt = null; |
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} else { |
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throw new IllegalStateException(); |
552 |
< |
} |
552 |
> |
} |
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expectedModCount = modCount; |
554 |
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} |
555 |
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} |
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size = 0; |
570 |
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} |
571 |
|
|
572 |
+ |
@SuppressWarnings("unchecked") |
573 |
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public E poll() { |
574 |
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if (size == 0) |
575 |
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return null; |
595 |
|
* position before i. This fact is used by iterator.remove so as to |
596 |
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* avoid missing traversing elements. |
597 |
|
*/ |
598 |
+ |
@SuppressWarnings("unchecked") |
599 |
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private E removeAt(int i) { |
600 |
< |
assert i >= 0 && i < size; |
600 |
> |
// assert i >= 0 && i < size; |
601 |
|
modCount++; |
602 |
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int s = --size; |
603 |
|
if (s == i) // removed last element |
634 |
|
siftUpComparable(k, x); |
635 |
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} |
636 |
|
|
637 |
+ |
@SuppressWarnings("unchecked") |
638 |
|
private void siftUpComparable(int k, E x) { |
639 |
|
Comparable<? super E> key = (Comparable<? super E>) x; |
640 |
|
while (k > 0) { |
648 |
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queue[k] = key; |
649 |
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} |
650 |
|
|
651 |
+ |
@SuppressWarnings("unchecked") |
652 |
|
private void siftUpUsingComparator(int k, E x) { |
653 |
|
while (k > 0) { |
654 |
|
int parent = (k - 1) >>> 1; |
676 |
|
siftDownComparable(k, x); |
677 |
|
} |
678 |
|
|
679 |
+ |
@SuppressWarnings("unchecked") |
680 |
|
private void siftDownComparable(int k, E x) { |
681 |
|
Comparable<? super E> key = (Comparable<? super E>)x; |
682 |
|
int half = size >>> 1; // loop while a non-leaf |
695 |
|
queue[k] = key; |
696 |
|
} |
697 |
|
|
698 |
+ |
@SuppressWarnings("unchecked") |
699 |
|
private void siftDownUsingComparator(int k, E x) { |
700 |
|
int half = size >>> 1; |
701 |
|
while (k < half) { |
717 |
|
* Establishes the heap invariant (described above) in the entire tree, |
718 |
|
* assuming nothing about the order of the elements prior to the call. |
719 |
|
*/ |
720 |
+ |
@SuppressWarnings("unchecked") |
721 |
|
private void heapify() { |
722 |
|
for (int i = (size >>> 1) - 1; i >= 0; i--) |
723 |
|
siftDown(i, (E) queue[i]); |
737 |
|
} |
738 |
|
|
739 |
|
/** |
740 |
< |
* Saves the state of the instance to a stream (that |
694 |
< |
* is, serializes it). |
740 |
> |
* Saves this queue to a stream (that is, serializes it). |
741 |
|
* |
742 |
|
* @serialData The length of the array backing the instance is |
743 |
|
* emitted (int), followed by all of its elements |
745 |
|
* @param s the stream |
746 |
|
*/ |
747 |
|
private void writeObject(java.io.ObjectOutputStream s) |
748 |
< |
throws java.io.IOException{ |
748 |
> |
throws java.io.IOException { |
749 |
|
// Write out element count, and any hidden stuff |
750 |
|
s.defaultWriteObject(); |
751 |
|
|
771 |
|
// Read in (and discard) array length |
772 |
|
s.readInt(); |
773 |
|
|
774 |
< |
queue = new Object[size]; |
774 |
> |
queue = new Object[size]; |
775 |
|
|
776 |
|
// Read in all elements. |
777 |
|
for (int i = 0; i < size; i++) |
778 |
|
queue[i] = s.readObject(); |
779 |
|
|
780 |
< |
// Elements are guaranteed to be in "proper order", but the |
781 |
< |
// spec has never explained what that might be. |
782 |
< |
heapify(); |
780 |
> |
// Elements are guaranteed to be in "proper order", but the |
781 |
> |
// spec has never explained what that might be. |
782 |
> |
heapify(); |
783 |
> |
} |
784 |
> |
|
785 |
> |
// wrapping constructor in method avoids transient javac problems |
786 |
> |
final PriorityQueueSpliterator<E> spliterator(int origin, int fence, |
787 |
> |
int expectedModCount) { |
788 |
> |
return new PriorityQueueSpliterator(this, origin, fence, |
789 |
> |
expectedModCount); |
790 |
> |
} |
791 |
> |
|
792 |
> |
public Stream<E> stream() { |
793 |
> |
int flags = Streams.STREAM_IS_SIZED; |
794 |
> |
return Streams.stream |
795 |
> |
(() -> spliterator(0, size, modCount), flags); |
796 |
> |
} |
797 |
> |
public Stream<E> parallelStream() { |
798 |
> |
int flags = Streams.STREAM_IS_SIZED; |
799 |
> |
return Streams.parallelStream |
800 |
> |
(() -> spliterator(0, size, modCount), flags); |
801 |
> |
} |
802 |
> |
|
803 |
> |
/** Index-based split-by-two Spliterator */ |
804 |
> |
static final class PriorityQueueSpliterator<E> |
805 |
> |
implements Spliterator<E>, Iterator<E> { |
806 |
> |
private final PriorityQueue<E> pq; |
807 |
> |
private int index; // current index, modified on advance/split |
808 |
> |
private final int fence; // one past last index |
809 |
> |
private final int expectedModCount; // for comodification checks |
810 |
> |
|
811 |
> |
/** Create new spliterator covering the given range */ |
812 |
> |
PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence, |
813 |
> |
int expectedModCount) { |
814 |
> |
this.pq = pq; this.index = origin; this.fence = fence; |
815 |
> |
this.expectedModCount = expectedModCount; |
816 |
> |
} |
817 |
> |
|
818 |
> |
public PriorityQueueSpliterator<E> trySplit() { |
819 |
> |
int lo = index, mid = (lo + fence) >>> 1; |
820 |
> |
return (lo >= mid) ? null : |
821 |
> |
new PriorityQueueSpliterator<E>(pq, lo, index = mid, |
822 |
> |
expectedModCount); |
823 |
> |
} |
824 |
> |
|
825 |
> |
public void forEach(Block<? super E> block) { |
826 |
> |
Object[] a; int i, hi; // hoist accesses and checks from loop |
827 |
> |
if (block == null) |
828 |
> |
throw new NullPointerException(); |
829 |
> |
if ((a = pq.queue).length >= (hi = fence) && |
830 |
> |
(i = index) >= 0 && i < hi) { |
831 |
> |
index = hi; |
832 |
> |
do { |
833 |
> |
@SuppressWarnings("unchecked") E e = (E) a[i]; |
834 |
> |
block.accept(e); |
835 |
> |
} while (++i < hi); |
836 |
> |
if (pq.modCount != expectedModCount) |
837 |
> |
throw new ConcurrentModificationException(); |
838 |
> |
} |
839 |
> |
} |
840 |
> |
|
841 |
> |
public boolean tryAdvance(Block<? super E> block) { |
842 |
> |
if (index >= 0 && index < fence) { |
843 |
> |
if (pq.modCount != expectedModCount) |
844 |
> |
throw new ConcurrentModificationException(); |
845 |
> |
@SuppressWarnings("unchecked") E e = |
846 |
> |
(E)pq.queue[index++]; |
847 |
> |
block.accept(e); |
848 |
> |
return true; |
849 |
> |
} |
850 |
> |
return false; |
851 |
> |
} |
852 |
> |
|
853 |
> |
public long estimateSize() { return (long)(fence - index); } |
854 |
> |
public boolean hasExactSize() { return true; } |
855 |
> |
public boolean hasExactSplits() { return true; } |
856 |
> |
|
857 |
> |
// Iterator support |
858 |
> |
public Iterator<E> iterator() { return this; } |
859 |
> |
public void remove() { throw new UnsupportedOperationException(); } |
860 |
> |
public boolean hasNext() { return index >= 0 && index < fence; } |
861 |
> |
|
862 |
> |
public E next() { |
863 |
> |
if (index < 0 || index >= fence) |
864 |
> |
throw new NoSuchElementException(); |
865 |
> |
if (pq.modCount != expectedModCount) |
866 |
> |
throw new ConcurrentModificationException(); |
867 |
> |
@SuppressWarnings("unchecked") E e = |
868 |
> |
(E) pq.queue[index++]; |
869 |
> |
return e; |
870 |
> |
} |
871 |
|
} |
872 |
|
} |