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Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.62 by jsr166, Thu Feb 16 08:17:21 2006 UTC vs.
Revision 1.102 by jsr166, Wed Dec 31 07:54:13 2014 UTC

#	Line 1 | Line 1
1		/*
2	<	* %W% %E%
2	>	* Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
3	>	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4		*
5	<	* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
6	<	* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
5	>	* This code is free software; you can redistribute it and/or modify it
6	>	* under the terms of the GNU General Public License version 2 only, as
7	>	* published by the Free Software Foundation.  Oracle designates this
8	>	* particular file as subject to the "Classpath" exception as provided
9	>	* by Oracle in the LICENSE file that accompanied this code.
10	>	*
11	>	* This code is distributed in the hope that it will be useful, but WITHOUT
12	>	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13	>	* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14	>	* version 2 for more details (a copy is included in the LICENSE file that
15	>	* accompanied this code).
16	>	*
17	>	* You should have received a copy of the GNU General Public License version
18	>	* 2 along with this work; if not, write to the Free Software Foundation,
19	>	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20	>	*
21	>	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22	>	* or visit www.oracle.com if you need additional information or have any
23	>	* questions.
24		*/
25
26		package java.util;
27
28	+	import java.util.function.Consumer;
29	+	import java.util.stream.Stream;
30	+
31		/**
32	<	* An unbounded priority {@linkplain Queue queue} based on a priority
33	<	* heap.  The elements of the priority queue are ordered according to
34	<	* their {@linkplain Comparable natural ordering}, or by a {@link
35	<	* Comparator} provided at queue construction time, depending on which
36	<	* constructor is used.  A priority queue does not permit
37	<	* <tt>null</tt> elements.  A priority queue relying on natural
38	<	* ordering also does not permit insertion of non-comparable objects
39	<	* (doing so may result in <tt>ClassCastException</tt>).
32	>	* An unbounded priority {@linkplain Queue queue} based on a priority heap.
33	>	* The elements of the priority queue are ordered according to their
34	>	* {@linkplain Comparable natural ordering}, or by a {@link Comparator}
35	>	* provided at queue construction time, depending on which constructor is
36	>	* used.  A priority queue does not permit {@code null} elements.
37	>	* A priority queue relying on natural ordering also does not permit
38	>	* insertion of non-comparable objects (doing so may result in
39	>	* {@code ClassCastException}).
40		*
41		* <p>The <em>head</em> of this queue is the <em>least</em> element
42		* with respect to the specified ordering.  If multiple elements are
43		* tied for least value, the head is one of those elements -- ties are
44	<	* broken arbitrarily.  The queue retrieval operations <tt>poll</tt>,
45	<	* <tt>remove</tt>, <tt>peek</tt>, and <tt>element</tt> access the
44	>	* broken arbitrarily.  The queue retrieval operations {@code poll},
45	>	* {@code remove}, {@code peek}, and {@code element} access the
46		* element at the head of the queue.
47		*
48		* <p>A priority queue is unbounded, but has an internal
#	Line 36 | Line 57 | package java.util;
57		* Iterator} interfaces.  The Iterator provided in method {@link
58		* #iterator()} is <em>not</em> guaranteed to traverse the elements of
59		* the priority queue in any particular order. If you need ordered
60	<	* traversal, consider using <tt>Arrays.sort(pq.toArray())</tt>.
60	>	* traversal, consider using {@code Arrays.sort(pq.toArray())}.
61		*
62	<	* <p> <strong>Note that this implementation is not synchronized.</strong>
63	<	* Multiple threads should not access a <tt>PriorityQueue</tt>
64	<	* instance concurrently if any of the threads modifies the list
65	<	* structurally. Instead, use the thread-safe {@link
62	>	* <p><strong>Note that this implementation is not synchronized.</strong>
63	>	* Multiple threads should not access a {@code PriorityQueue}
64	>	* instance concurrently if any of the threads modifies the queue.
65	>	* Instead, use the thread-safe {@link
66		* java.util.concurrent.PriorityBlockingQueue} class.
67		*
68	<	* <p>Implementation note: this implementation provides O(log(n)) time
69	<	* for the insertion methods (<tt>offer</tt>, <tt>poll</tt>,
70	<	* <tt>remove()</tt> and <tt>add</tt>) methods; linear time for the
71	<	* <tt>remove(Object)</tt> and <tt>contains(Object)</tt> methods; and
72	<	* constant time for the retrieval methods (<tt>peek</tt>,
73	<	* <tt>element</tt>, and <tt>size</tt>).
68	>	* <p>Implementation note: this implementation provides
69	>	* O(log(n)) time for the enqueuing and dequeuing methods
70	>	* ({@code offer}, {@code poll}, {@code remove()} and {@code add});
71	>	* linear time for the {@code remove(Object)} and {@code contains(Object)}
72	>	* methods; and constant time for the retrieval methods
73	>	* ({@code peek}, {@code element}, and {@code size}).
74		*
75		* <p>This class is a member of the
76	<	* <a href="{@docRoot}/../guide/collections/index.html">
76	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
77		* Java Collections Framework</a>.
78	+	*
79		* @since 1.5
80	<	* @version %I%, %G%
81	<	* @author Josh Bloch
60	<	* @param <E> the type of elements held in this collection
80	>	* @author Josh Bloch, Doug Lea
81	>	* @param <E> the type of elements held in this queue
82		*/
83		public class PriorityQueue<E> extends AbstractQueue<E>
84		implements java.io.Serializable {
#	Line 74 | Line 95 | public class PriorityQueue<E> extends Ab
95		* heap and each descendant d of n, n <= d.  The element with the
96		* lowest value is in queue[0], assuming the queue is nonempty.
97		*/
98	<	private transient Object[] queue;
98	>	transient Object[] queue; // non-private to simplify nested class access
99
100		/**
101		* The number of elements in the priority queue.
102		*/
103	<	private int size = 0;
103	>	private int size;
104
105		/**
106		* The comparator, or null if priority queue uses elements'
#	Line 91 | Line 112 | public class PriorityQueue<E> extends Ab
112		* The number of times this priority queue has been
113		* <i>structurally modified</i>.  See AbstractList for gory details.
114		*/
115	<	private transient int modCount = 0;
115	>	transient int modCount = 0; // non-private to simplify nested class access
116
117		/**
118	<	* Creates a <tt>PriorityQueue</tt> with the default initial
118	>	* Creates a {@code PriorityQueue} with the default initial
119		* capacity (11) that orders its elements according to their
120		* {@linkplain Comparable natural ordering}.
121		*/
#	Line 103 | Line 124 | public class PriorityQueue<E> extends Ab
124		}
125
126		/**
127	<	* Creates a <tt>PriorityQueue</tt> with the specified initial
127	>	* Creates a {@code PriorityQueue} with the specified initial
128		* capacity that orders its elements according to their
129		* {@linkplain Comparable natural ordering}.
130		*
131		* @param initialCapacity the initial capacity for this priority queue
132	<	* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less
133	<	* than 1
132	>	* @throws IllegalArgumentException if {@code initialCapacity} is less
133	>	*         than 1
134		*/
135		public PriorityQueue(int initialCapacity) {
136		this(initialCapacity, null);
137		}
138
139		/**
140	<	* Creates a <tt>PriorityQueue</tt> with the specified initial capacity
140	>	* Creates a {@code PriorityQueue} with the specified initial capacity
141		* that orders its elements according to the specified comparator.
142		*
143		* @param  initialCapacity the initial capacity for this priority queue
144	<	* @param  comparator the comparator that will be used to order
145	<	*         this priority queue.  If <tt>null</tt>, the <i>natural
146	<	*         ordering</i> of the elements will be used.
147	<	* @throws IllegalArgumentException if <tt>initialCapacity</tt> is
144	>	* @param  comparator the comparator that will be used to order this
145	>	*         priority queue.  If {@code null}, the {@linkplain Comparable
146	>	*         natural ordering} of the elements will be used.
147	>	* @throws IllegalArgumentException if {@code initialCapacity} is
148		*         less than 1
149		*/
150		public PriorityQueue(int initialCapacity,
#	Line 137 | Line 158 | public class PriorityQueue<E> extends Ab
158		}
159
160		/**
161	<	* Creates a <tt>PriorityQueue</tt> containing the elements in the
162	<	* specified collection.   If the specified collection is an
163	<	* instance of a {@link java.util.SortedSet} or is another
164	<	* <tt>PriorityQueue</tt>, the priority queue will be ordered
165	<	* according to the same ordering.  Otherwise, this priority queue
166	<	* will be ordered according to the natural ordering of its elements.
161	>	* Creates a {@code PriorityQueue} containing the elements in the
162	>	* specified collection.  If the specified collection is an instance of
163	>	* a {@link SortedSet} or is another {@code PriorityQueue}, this
164	>	* priority queue will be ordered according to the same ordering.
165	>	* Otherwise, this priority queue will be ordered according to the
166	>	* {@linkplain Comparable natural ordering} of its elements.
167		*
168		* @param  c the collection whose elements are to be placed
169		*         into this priority queue
#	Line 152 | Line 173 | public class PriorityQueue<E> extends Ab
173		* @throws NullPointerException if the specified collection or any
174		*         of its elements are null
175		*/
176	+	@SuppressWarnings("unchecked")
177		public PriorityQueue(Collection<? extends E> c) {
178	<	initFromCollection(c);
179	<	if (c instanceof SortedSet)
180	<	comparator = (Comparator<? super E>)
181	<	((SortedSet<? extends E>)c).comparator();
182	<	else if (c instanceof PriorityQueue)
183	<	comparator = (Comparator<? super E>)
184	<	((PriorityQueue<? extends E>)c).comparator();
178	>	if (c instanceof SortedSet<?>) {
179	>	SortedSet<? extends E> ss = (SortedSet<? extends E>) c;
180	>	this.comparator = (Comparator<? super E>) ss.comparator();
181	>	initElementsFromCollection(ss);
182	>	}
183	>	else if (c instanceof PriorityQueue<?>) {
184	>	PriorityQueue<? extends E> pq = (PriorityQueue<? extends E>) c;
185	>	this.comparator = (Comparator<? super E>) pq.comparator();
186	>	initFromPriorityQueue(pq);
187	>	}
188		else {
189	<	comparator = null;
190	<	heapify();
189	>	this.comparator = null;
190	>	initFromCollection(c);
191		}
192		}
193
194		/**
195	<	* Creates a <tt>PriorityQueue</tt> containing the elements in the
195	>	* Creates a {@code PriorityQueue} containing the elements in the
196		* specified priority queue.  This priority queue will be
197		* ordered according to the same ordering as the given priority
198		* queue.
199		*
200		* @param  c the priority queue whose elements are to be placed
201		*         into this priority queue
202	<	* @throws ClassCastException if elements of <tt>c</tt> cannot be
203	<	*         compared to one another according to <tt>c</tt>'s
202	>	* @throws ClassCastException if elements of {@code c} cannot be
203	>	*         compared to one another according to {@code c}'s
204		*         ordering
205		* @throws NullPointerException if the specified priority queue or any
206		*         of its elements are null
207		*/
208	+	@SuppressWarnings("unchecked")
209		public PriorityQueue(PriorityQueue<? extends E> c) {
210	<	comparator = (Comparator<? super E>)c.comparator();
211	<	initFromCollection(c);
210	>	this.comparator = (Comparator<? super E>) c.comparator();
211	>	initFromPriorityQueue(c);
212		}
213
214		/**
215	<	* Creates a <tt>PriorityQueue</tt> containing the elements in the
216	<	* specified sorted set.  This priority queue will be ordered
215	>	* Creates a {@code PriorityQueue} containing the elements in the
216	>	* specified sorted set.   This priority queue will be ordered
217		* according to the same ordering as the given sorted set.
218		*
219		* @param  c the sorted set whose elements are to be placed
220	<	*         into this priority queue.
220	>	*         into this priority queue
221		* @throws ClassCastException if elements of the specified sorted
222		*         set cannot be compared to one another according to the
223		*         sorted set's ordering
224		* @throws NullPointerException if the specified sorted set or any
225		*         of its elements are null
226		*/
227	+	@SuppressWarnings("unchecked")
228		public PriorityQueue(SortedSet<? extends E> c) {
229	<	comparator = (Comparator<? super E>)c.comparator();
230	<	initFromCollection(c);
229	>	this.comparator = (Comparator<? super E>) c.comparator();
230	>	initElementsFromCollection(c);
231		}
232
233	<	/**
234	<	* Initialize queue array with elements from the given Collection.
235	<	* @param c the collection
236	<	*/
237	<	private void initFromCollection(Collection<? extends E> c) {
233	>	private void initFromPriorityQueue(PriorityQueue<? extends E> c) {
234	>	if (c.getClass() == PriorityQueue.class) {
235	>	this.queue = c.toArray();
236	>	this.size = c.size();
237	>	} else {
238	>	initFromCollection(c);
239	>	}
240	>	}
241	>
242	>	private void initElementsFromCollection(Collection<? extends E> c) {
243		Object[] a = c.toArray();
244		// If c.toArray incorrectly doesn't return Object[], copy it.
245		if (a.getClass() != Object[].class)
246		a = Arrays.copyOf(a, a.length, Object[].class);
247	<	queue = a;
248	<	size = a.length;
247	>	int len = a.length;
248	>	if (len == 1 || this.comparator != null)
249	>	for (int i = 0; i < len; i++)
250	>	if (a[i] == null)
251	>	throw new NullPointerException();
252	>	this.queue = a;
253	>	this.size = a.length;
254	>	}
255	>
256	>	/**
257	>	* Initializes queue array with elements from the given Collection.
258	>	*
259	>	* @param c the collection
260	>	*/
261	>	private void initFromCollection(Collection<? extends E> c) {
262	>	initElementsFromCollection(c);
263	>	heapify();
264		}
265
266		/**
267	+	* The maximum size of array to allocate.
268	+	* Some VMs reserve some header words in an array.
269	+	* Attempts to allocate larger arrays may result in
270	+	* OutOfMemoryError: Requested array size exceeds VM limit
271	+	*/
272	+	private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
273	+
274	+	/**
275		* Increases the capacity of the array.
276		*
277		* @param minCapacity the desired minimum capacity
278		*/
279		private void grow(int minCapacity) {
280	<	if (minCapacity < 0) // overflow
226	<	throw new OutOfMemoryError();
227	<	int oldCapacity = queue.length;
280	>	int oldCapacity = queue.length;
281		// Double size if small; else grow by 50%
282	<	int newCapacity = ((oldCapacity < 64)?
283	<	((oldCapacity + 1) * 2):
284	<	((oldCapacity / 2) * 3));
285	<	if (newCapacity < 0) // overflow
286	<	newCapacity = Integer.MAX_VALUE;
287	<	if (newCapacity < minCapacity)
235	<	newCapacity = minCapacity;
282	>	int newCapacity = oldCapacity + ((oldCapacity < 64) ?
283	>	(oldCapacity + 2) :
284	>	(oldCapacity >> 1));
285	>	// overflow-conscious code
286	>	if (newCapacity - MAX_ARRAY_SIZE > 0)
287	>	newCapacity = hugeCapacity(minCapacity);
288		queue = Arrays.copyOf(queue, newCapacity);
289		}
290
291	+	private static int hugeCapacity(int minCapacity) {
292	+	if (minCapacity < 0) // overflow
293	+	throw new OutOfMemoryError();
294	+	return (minCapacity > MAX_ARRAY_SIZE) ?
295	+	Integer.MAX_VALUE :
296	+	MAX_ARRAY_SIZE;
297	+	}
298	+
299		/**
300		* Inserts the specified element into this priority queue.
301		*
302	<	* @return <tt>true</tt> (as specified by {@link Collection#add})
302	>	* @return {@code true} (as specified by {@link Collection#add})
303		* @throws ClassCastException if the specified element cannot be
304		*         compared with elements currently in this priority queue
305		*         according to the priority queue's ordering
#	Line 252 | Line 312 | public class PriorityQueue<E> extends Ab
312		/**
313		* Inserts the specified element into this priority queue.
314		*
315	<	* @return <tt>true</tt> (as specified by {@link Queue#offer})
315	>	* @return {@code true} (as specified by {@link Queue#offer})
316		* @throws ClassCastException if the specified element cannot be
317		*         compared with elements currently in this priority queue
318		*         according to the priority queue's ordering
#	Line 273 | Line 333 | public class PriorityQueue<E> extends Ab
333		return true;
334		}
335
336	+	@SuppressWarnings("unchecked")
337		public E peek() {
338	<	if (size == 0)
278	<	return null;
279	<	return (E) queue[0];
338	>	return (size == 0) ? null : (E) queue[0];
339		}
340
341		private int indexOf(Object o) {
342	<	if (o != null) {
342	>	if (o != null) {
343		for (int i = 0; i < size; i++)
344		if (o.equals(queue[i]))
345		return i;
#	Line 290 | Line 349 | public class PriorityQueue<E> extends Ab
349
350		/**
351		* Removes a single instance of the specified element from this queue,
352	<	* if it is present.  More formally, removes an element <tt>e</tt> such
353	<	* that <tt>o.equals(e)</tt>, if this queue contains one or more such
354	<	* elements.  Returns true if this queue contained the specified element
355	<	* (or equivalently, if this queue changed as a result of the call).
352	>	* if it is present.  More formally, removes an element {@code e} such
353	>	* that {@code o.equals(e)}, if this queue contains one or more such
354	>	* elements.  Returns {@code true} if and only if this queue contained
355	>	* the specified element (or equivalently, if this queue changed as a
356	>	* result of the call).
357		*
358		* @param o element to be removed from this queue, if present
359	<	* @return <tt>true</tt> if this queue changed as a result of the call
359	>	* @return {@code true} if this queue changed as a result of the call
360		*/
361		public boolean remove(Object o) {
362	<	int i = indexOf(o);
363	<	if (i == -1)
364	<	return false;
365	<	else {
366	<	removeAt(i);
367	<	return true;
368	<	}
362	>	int i = indexOf(o);
363	>	if (i == -1)
364	>	return false;
365	>	else {
366	>	removeAt(i);
367	>	return true;
368	>	}
369		}
370
371		/**
#	Line 313 | Line 373 | public class PriorityQueue<E> extends Ab
373		* Needed by iterator.remove.
374		*
375		* @param o element to be removed from this queue, if present
376	<	* @return <tt>true</tt> if removed
376	>	* @return {@code true} if removed
377		*/
378		boolean removeEq(Object o) {
379	<	for (int i = 0; i < size; i++) {
380	<	if (o == queue[i]) {
379	>	for (int i = 0; i < size; i++) {
380	>	if (o == queue[i]) {
381		removeAt(i);
382		return true;
383		}
#	Line 326 | Line 386 | public class PriorityQueue<E> extends Ab
386		}
387
388		/**
389	<	* Returns <tt>true</tt> if this queue contains the specified element.
390	<	* More formally, returns <tt>true</tt> if and only if this queue contains
391	<	* at least one element <tt>e</tt> such that <tt>o.equals(e)</tt>.
389	>	* Returns {@code true} if this queue contains the specified element.
390	>	* More formally, returns {@code true} if and only if this queue contains
391	>	* at least one element {@code e} such that {@code o.equals(e)}.
392		*
393		* @param o object to be checked for containment in this queue
394	<	* @return <tt>true</tt> if this queue contains the specified element
394	>	* @return {@code true} if this queue contains the specified element
395		*/
396		public boolean contains(Object o) {
397	<	return indexOf(o) != -1;
397	>	return indexOf(o) >= 0;
398		}
399
400		/**
401	<	* Returns an array containing all of the elements in this queue,
401	>	* Returns an array containing all of the elements in this queue.
402		* The elements are in no particular order.
403		*
404		* <p>The returned array will be "safe" in that no references to it are
405	<	* maintained by this list.  (In other words, this method must allocate
405	>	* maintained by this queue.  (In other words, this method must allocate
406		* a new array).  The caller is thus free to modify the returned array.
407		*
408	+	* <p>This method acts as bridge between array-based and collection-based
409	+	* APIs.
410	+	*
411		* @return an array containing all of the elements in this queue
412		*/
413		public Object[] toArray() {
#	Line 352 | Line 415 | public class PriorityQueue<E> extends Ab
415		}
416
417		/**
418	<	* Returns an array containing all of the elements in this queue.
419	<	* The elements are in no particular order.  The runtime type of
420	<	* the returned array is that of the specified array.  If the queue
421	<	* fits in the specified array, it is returned therein.
422	<	* Otherwise, a new array is allocated with the runtime type of
423	<	* the specified array and the size of this queue.
418	>	* Returns an array containing all of the elements in this queue; the
419	>	* runtime type of the returned array is that of the specified array.
420	>	* The returned array elements are in no particular order.
421	>	* If the queue fits in the specified array, it is returned therein.
422	>	* Otherwise, a new array is allocated with the runtime type of the
423	>	* specified array and the size of this queue.
424		*
425		* <p>If the queue fits in the specified array with room to spare
426		* (i.e., the array has more elements than the queue), the element in
427		* the array immediately following the end of the collection is set to
428	<	* <tt>null</tt>.  (This is useful in determining the length of the
429	<	* queue <i>only</i> if the caller knows that the queue does not contain
430	<	* any null elements.)
428	>	* {@code null}.
429	>	*
430	>	* <p>Like the {@link #toArray()} method, this method acts as bridge between
431	>	* array-based and collection-based APIs.  Further, this method allows
432	>	* precise control over the runtime type of the output array, and may,
433	>	* under certain circumstances, be used to save allocation costs.
434	>	*
435	>	* <p>Suppose {@code x} is a queue known to contain only strings.
436	>	* The following code can be used to dump the queue into a newly
437	>	* allocated array of {@code String}:
438	>	*
439	>	*  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
440	>	*
441	>	* Note that {@code toArray(new Object[0])} is identical in function to
442	>	* {@code toArray()}.
443		*
444		* @param a the array into which the elements of the queue are to
445		*          be stored, if it is big enough; otherwise, a new array of the
446		*          same runtime type is allocated for this purpose.
447	<	* @return an array containing the elements of the queue
447	>	* @return an array containing all of the elements in this queue
448		* @throws ArrayStoreException if the runtime type of the specified array
449		*         is not a supertype of the runtime type of every element in
450		*         this queue
451		* @throws NullPointerException if the specified array is null
452		*/
453	+	@SuppressWarnings("unchecked")
454		public <T> T[] toArray(T[] a) {
455	+	final int size = this.size;
456		if (a.length < size)
457		// Make a new array of a's runtime type, but my contents:
458		return (T[]) Arrays.copyOf(queue, size, a.getClass());
459	<	System.arraycopy(queue, 0, a, 0, size);
459	>	System.arraycopy(queue, 0, a, 0, size);
460		if (a.length > size)
461		a[size] = null;
462		return a;
#	Line 400 | Line 477 | public class PriorityQueue<E> extends Ab
477		* Index (into queue array) of element to be returned by
478		* subsequent call to next.
479		*/
480	<	private int cursor = 0;
480	>	private int cursor;
481
482		/**
483		* Index of element returned by most recent call to next,
#	Line 418 | Line 495 | public class PriorityQueue<E> extends Ab
495		* after we've completed the "normal" iteration.
496		*
497		* We expect that most iterations, even those involving removals,
498	<	* will not use need to store elements in this field.
498	>	* will not need to store elements in this field.
499		*/
500	<	private ArrayDeque<E> forgetMeNot = null;
500	>	private ArrayDeque<E> forgetMeNot;
501
502		/**
503		* Element returned by the most recent call to next iff that
504		* element was drawn from the forgetMeNot list.
505		*/
506	<	private E lastRetElt = null;
506	>	private E lastRetElt;
507
508		/**
509		* The modCount value that the iterator believes that the backing
510	<	* List should have.  If this expectation is violated, the iterator
510	>	* Queue should have.  If this expectation is violated, the iterator
511		* has detected concurrent modification.
512		*/
513		private int expectedModCount = modCount;
#	Line 440 | Line 517 | public class PriorityQueue<E> extends Ab
517		(forgetMeNot != null && !forgetMeNot.isEmpty());
518		}
519
520	+	@SuppressWarnings("unchecked")
521		public E next() {
522		if (expectedModCount != modCount)
523		throw new ConcurrentModificationException();
#	Line 457 | Line 535 | public class PriorityQueue<E> extends Ab
535		public void remove() {
536		if (expectedModCount != modCount)
537		throw new ConcurrentModificationException();
460	–	if (lastRet == -1 && lastRetElt == null)
461	–	throw new IllegalStateException();
538		if (lastRet != -1) {
539		E moved = PriorityQueue.this.removeAt(lastRet);
540		lastRet = -1;
#	Line 466 | Line 542 | public class PriorityQueue<E> extends Ab
542		cursor--;
543		else {
544		if (forgetMeNot == null)
545	<	forgetMeNot = new ArrayDeque<E>();
545	>	forgetMeNot = new ArrayDeque<>();
546		forgetMeNot.add(moved);
547		}
548	<	} else {
548	>	} else if (lastRetElt != null) {
549		PriorityQueue.this.removeEq(lastRetElt);
550		lastRetElt = null;
551	+	} else {
552	+	throw new IllegalStateException();
553		}
554		expectedModCount = modCount;
555		}
478	–
556		}
557
558		public int size() {
#	Line 493 | Line 570 | public class PriorityQueue<E> extends Ab
570		size = 0;
571		}
572
573	+	@SuppressWarnings("unchecked")
574		public E poll() {
575		if (size == 0)
576		return null;
577		int s = --size;
578		modCount++;
579	<	E result = (E)queue[0];
580	<	E x = (E)queue[s];
579	>	E result = (E) queue[0];
580	>	E x = (E) queue[s];
581		queue[s] = null;
582		if (s != 0)
583		siftDown(0, x);
#	Line 516 | Line 594 | public class PriorityQueue<E> extends Ab
594		* i.  Under these circumstances, this method returns the element
595		* that was previously at the end of the list and is now at some
596		* position before i. This fact is used by iterator.remove so as to
597	<	* avoid missing traverseing elements.
597	>	* avoid missing traversing elements.
598		*/
599	+	@SuppressWarnings("unchecked")
600		private E removeAt(int i) {
601	<	assert i >= 0 && i < size;
601	>	// assert i >= 0 && i < size;
602		modCount++;
603		int s = --size;
604		if (s == i) // removed last element
#	Line 556 | Line 635 | public class PriorityQueue<E> extends Ab
635		siftUpComparable(k, x);
636		}
637
638	+	@SuppressWarnings("unchecked")
639		private void siftUpComparable(int k, E x) {
640		Comparable<? super E> key = (Comparable<? super E>) x;
641		while (k > 0) {
642		int parent = (k - 1) >>> 1;
643		Object e = queue[parent];
644	<	if (key.compareTo((E)e) >= 0)
644	>	if (key.compareTo((E) e) >= 0)
645		break;
646		queue[k] = e;
647		k = parent;
#	Line 569 | Line 649 | public class PriorityQueue<E> extends Ab
649		queue[k] = key;
650		}
651
652	+	@SuppressWarnings("unchecked")
653		private void siftUpUsingComparator(int k, E x) {
654		while (k > 0) {
655		int parent = (k - 1) >>> 1;
656		Object e = queue[parent];
657	<	if (comparator.compare(x, (E)e) >= 0)
657	>	if (comparator.compare(x, (E) e) >= 0)
658		break;
659		queue[k] = e;
660		k = parent;
#	Line 596 | Line 677 | public class PriorityQueue<E> extends Ab
677		siftDownComparable(k, x);
678		}
679
680	+	@SuppressWarnings("unchecked")
681		private void siftDownComparable(int k, E x) {
682		Comparable<? super E> key = (Comparable<? super E>)x;
683		int half = size >>> 1;        // loop while a non-leaf
#	Line 604 | Line 686 | public class PriorityQueue<E> extends Ab
686		Object c = queue[child];
687		int right = child + 1;
688		if (right < size &&
689	<	((Comparable<? super E>)c).compareTo((E)queue[right]) > 0)
689	>	((Comparable<? super E>) c).compareTo((E) queue[right]) > 0)
690		c = queue[child = right];
691	<	if (key.compareTo((E)c) <= 0)
691	>	if (key.compareTo((E) c) <= 0)
692		break;
693		queue[k] = c;
694		k = child;
#	Line 614 | Line 696 | public class PriorityQueue<E> extends Ab
696		queue[k] = key;
697		}
698
699	+	@SuppressWarnings("unchecked")
700		private void siftDownUsingComparator(int k, E x) {
701		int half = size >>> 1;
702		while (k < half) {
#	Line 621 | Line 704 | public class PriorityQueue<E> extends Ab
704		Object c = queue[child];
705		int right = child + 1;
706		if (right < size &&
707	<	comparator.compare((E)c, (E)queue[right]) > 0)
707	>	comparator.compare((E) c, (E) queue[right]) > 0)
708		c = queue[child = right];
709	<	if (comparator.compare(x, (E)c) <= 0)
709	>	if (comparator.compare(x, (E) c) <= 0)
710		break;
711		queue[k] = c;
712		k = child;
#	Line 635 | Line 718 | public class PriorityQueue<E> extends Ab
718		* Establishes the heap invariant (described above) in the entire tree,
719		* assuming nothing about the order of the elements prior to the call.
720		*/
721	+	@SuppressWarnings("unchecked")
722		private void heapify() {
723		for (int i = (size >>> 1) - 1; i >= 0; i--)
724	<	siftDown(i, (E)queue[i]);
724	>	siftDown(i, (E) queue[i]);
725		}
726
727		/**
728		* Returns the comparator used to order the elements in this
729	<	* queue, or <tt>null</tt> if this queue is sorted according to
729	>	* queue, or {@code null} if this queue is sorted according to
730		* the {@linkplain Comparable natural ordering} of its elements.
731		*
732		* @return the comparator used to order this queue, or
733	<	*         <tt>null</tt> if this queue is sorted according to the
734	<	*         natural ordering of its elements.
733	>	*         {@code null} if this queue is sorted according to the
734	>	*         natural ordering of its elements
735		*/
736		public Comparator<? super E> comparator() {
737		return comparator;
738		}
739
740		/**
741	<	* Save the state of the instance to a stream (that
658	<	* is, serialize it).
741	>	* Saves this queue to a stream (that is, serializes it).
742		*
743		* @serialData The length of the array backing the instance is
744	<	* emitted (int), followed by all of its elements (each an
745	<	* <tt>Object</tt>) in the proper order.
744	>	*             emitted (int), followed by all of its elements
745	>	*             (each an {@code Object}) in the proper order.
746		* @param s the stream
747	+	* @throws java.io.IOException if an I/O error occurs
748		*/
749		private void writeObject(java.io.ObjectOutputStream s)
750	<	throws java.io.IOException{
750	>	throws java.io.IOException {
751		// Write out element count, and any hidden stuff
752		s.defaultWriteObject();
753
754	<	// Write out array length
755	<	// For compatibility with 1.5 version, must be at least 2.
672	<	s.writeInt(Math.max(2, queue.length));
754	>	// Write out array length, for compatibility with 1.5 version
755	>	s.writeInt(Math.max(2, size + 1));
756
757	<	// Write out all elements in the proper order.
758	<	for (int i=0; i<size; i++)
757	>	// Write out all elements in the "proper order".
758	>	for (int i = 0; i < size; i++)
759		s.writeObject(queue[i]);
760		}
761
762		/**
763	<	* Reconstitute the <tt>PriorityQueue</tt> instance from a stream
764	<	* (that is, deserialize it).
763	>	* Reconstitutes the {@code PriorityQueue} instance from a stream
764	>	* (that is, deserializes it).
765	>	*
766		* @param s the stream
767	+	* @throws ClassNotFoundException if the class of a serialized object
768	+	*         could not be found
769	+	* @throws java.io.IOException if an I/O error occurs
770		*/
771		private void readObject(java.io.ObjectInputStream s)
772		throws java.io.IOException, ClassNotFoundException {
773		// Read in size, and any hidden stuff
774		s.defaultReadObject();
775
776	<	// Read in array length and allocate array
777	<	int arrayLength = s.readInt();
778	<	queue = new Object[arrayLength];
779	<
780	<	// Read in all elements in the proper order.
781	<	for (int i=0; i<size; i++)
782	<	queue[i] = (E) s.readObject();
776	>	// Read in (and discard) array length
777	>	s.readInt();
778	>
779	>	queue = new Object[size];
780	>
781	>	// Read in all elements.
782	>	for (int i = 0; i < size; i++)
783	>	queue[i] = s.readObject();
784	>
785	>	// Elements are guaranteed to be in "proper order", but the
786	>	// spec has never explained what that might be.
787	>	heapify();
788		}
789
790	+	public Spliterator<E> spliterator() {
791	+	return new PriorityQueueSpliterator<E>(this, 0, -1, 0);
792	+	}
793	+
794	+	/**
795	+	* This is very similar to ArrayList Spliterator, except for extra
796	+	* null checks.
797	+	*/
798	+	static final class PriorityQueueSpliterator<E> implements Spliterator<E> {
799	+	private final PriorityQueue<E> pq;
800	+	private int index;            // current index, modified on advance/split
801	+	private int fence;            // -1 until first use
802	+	private int expectedModCount; // initialized when fence set
803	+
804	+	/** Creates new spliterator covering the given range */
805	+	PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
806	+	int expectedModCount) {
807	+	this.pq = pq;
808	+	this.index = origin;
809	+	this.fence = fence;
810	+	this.expectedModCount = expectedModCount;
811	+	}
812	+
813	+	private int getFence() { // initialize fence to size on first use
814	+	int hi;
815	+	if ((hi = fence) < 0) {
816	+	expectedModCount = pq.modCount;
817	+	hi = fence = pq.size;
818	+	}
819	+	return hi;
820	+	}
821	+
822	+	public Spliterator<E> trySplit() {
823	+	int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
824	+	return (lo >= mid) ? null :
825	+	new PriorityQueueSpliterator<E>(pq, lo, index = mid,
826	+	expectedModCount);
827	+	}
828	+
829	+	@SuppressWarnings("unchecked")
830	+	public void forEachRemaining(Consumer<? super E> action) {
831	+	int i, hi, mc; // hoist accesses and checks from loop
832	+	PriorityQueue<E> q; Object[] a;
833	+	if (action == null)
834	+	throw new NullPointerException();
835	+	if ((q = pq) != null && (a = q.queue) != null) {
836	+	if ((hi = fence) < 0) {
837	+	mc = q.modCount;
838	+	hi = q.size;
839	+	}
840	+	else
841	+	mc = expectedModCount;
842	+	if ((i = index) >= 0 && (index = hi) <= a.length) {
843	+	for (E e;; ++i) {
844	+	if (i < hi) {
845	+	if ((e = (E) a[i]) == null) // must be CME
846	+	break;
847	+	action.accept(e);
848	+	}
849	+	else if (q.modCount != mc)
850	+	break;
851	+	else
852	+	return;
853	+	}
854	+	}
855	+	}
856	+	throw new ConcurrentModificationException();
857	+	}
858	+
859	+	public boolean tryAdvance(Consumer<? super E> action) {
860	+	int hi = getFence(), lo = index;
861	+	if (lo >= 0 && lo < hi) {
862	+	index = lo + 1;
863	+	@SuppressWarnings("unchecked") E e = (E)pq.queue[lo];
864	+	if (e == null)
865	+	throw new ConcurrentModificationException();
866	+	action.accept(e);
867	+	if (pq.modCount != expectedModCount)
868	+	throw new ConcurrentModificationException();
869	+	return true;
870	+	}
871	+	return false;
872	+	}
873	+
874	+	public long estimateSize() {
875	+	return (long) (getFence() - index);
876	+	}
877	+
878	+	public int characteristics() {
879	+	return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL;
880	+	}
881	+	}
882		}

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