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Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.59 by jsr166, Tue Nov 29 08:52:26 2005 UTC vs.
Revision 1.88 by dl, Fri Feb 1 16:23:04 2013 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 2005 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	<	import java.util.*; // for javadoc (till 6280605 is fixed)
27	>	import java.util.stream.Stream;
28	>	import java.util.Spliterator;
29	>	import java.util.stream.Streams;
30	>	import java.util.function.Consumer;
31
32		/**
33	<	* An unbounded priority {@linkplain Queue queue} based on a priority
34	<	* heap.  The elements of the priority queue are ordered according to
35	<	* their {@linkplain Comparable natural ordering}, or by a {@link
36	<	* Comparator} provided at queue construction time, depending on which
37	<	* constructor is used.  A priority queue does not permit
38	<	* <tt>null</tt> elements.  A priority queue relying on natural
39	<	* ordering also does not permit insertion of non-comparable objects
40	<	* (doing so may result in <tt>ClassCastException</tt>).
33	>	* An unbounded priority {@linkplain Queue queue} based on a priority heap.
34	>	* The elements of the priority queue are ordered according to their
35	>	* {@linkplain Comparable natural ordering}, or by a {@link Comparator}
36	>	* provided at queue construction time, depending on which constructor is
37	>	* used.  A priority queue does not permit {@code null} elements.
38	>	* A priority queue relying on natural ordering also does not permit
39	>	* insertion of non-comparable objects (doing so may result in
40	>	* {@code ClassCastException}).
41		*
42		* <p>The <em>head</em> of this queue is the <em>least</em> element
43		* with respect to the specified ordering.  If multiple elements are
44		* tied for least value, the head is one of those elements -- ties are
45	<	* broken arbitrarily.  The queue retrieval operations <tt>poll</tt>,
46	<	* <tt>remove</tt>, <tt>peek</tt>, and <tt>element</tt> access the
45	>	* broken arbitrarily.  The queue retrieval operations {@code poll},
46	>	* {@code remove}, {@code peek}, and {@code element} access the
47		* element at the head of the queue.
48		*
49		* <p>A priority queue is unbounded, but has an internal
#	Line 37 | Line 58 | import java.util.*; // for javadoc (till
58		* Iterator} interfaces.  The Iterator provided in method {@link
59		* #iterator()} is <em>not</em> guaranteed to traverse the elements of
60		* the priority queue in any particular order. If you need ordered
61	<	* traversal, consider using <tt>Arrays.sort(pq.toArray())</tt>.
61	>	* traversal, consider using {@code Arrays.sort(pq.toArray())}.
62		*
63	<	* <p> <strong>Note that this implementation is not synchronized.</strong>
64	<	* Multiple threads should not access a <tt>PriorityQueue</tt>
65	<	* instance concurrently if any of the threads modifies the list
66	<	* structurally. Instead, use the thread-safe {@link
63	>	* <p><strong>Note that this implementation is not synchronized.</strong>
64	>	* Multiple threads should not access a {@code PriorityQueue}
65	>	* instance concurrently if any of the threads modifies the queue.
66	>	* Instead, use the thread-safe {@link
67		* java.util.concurrent.PriorityBlockingQueue} class.
68		*
69	<	* <p>Implementation note: this implementation provides O(log(n)) time
70	<	* for the insertion methods (<tt>offer</tt>, <tt>poll</tt>,
71	<	* <tt>remove()</tt> and <tt>add</tt>) methods; linear time for the
72	<	* <tt>remove(Object)</tt> and <tt>contains(Object)</tt> methods; and
73	<	* constant time for the retrieval methods (<tt>peek</tt>,
74	<	* <tt>element</tt>, and <tt>size</tt>).
69	>	* <p>Implementation note: this implementation provides
70	>	* O(log(n)) time for the enqueing and dequeing methods
71	>	* ({@code offer}, {@code poll}, {@code remove()} and {@code add});
72	>	* linear time for the {@code remove(Object)} and {@code contains(Object)}
73	>	* methods; and constant time for the retrieval methods
74	>	* ({@code peek}, {@code element}, and {@code size}).
75		*
76		* <p>This class is a member of the
77	<	* <a href="{@docRoot}/../guide/collections/index.html">
77	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
78		* Java Collections Framework</a>.
79	+	*
80		* @since 1.5
81	<	* @version 1.8, 08/27/05
60	<	* @author Josh Bloch
81	>	* @author Josh Bloch, Doug Lea
82		* @param <E> the type of elements held in this collection
83		*/
84		public class PriorityQueue<E> extends AbstractQueue<E>
#	Line 75 | Line 96 | public class PriorityQueue<E> extends Ab
96		* heap and each descendant d of n, n <= d.  The element with the
97		* lowest value is in queue[0], assuming the queue is nonempty.
98		*/
99	<	private transient Object[] queue;
99	>	transient Object[] queue; // non-private to simplify nested class access
100
101		/**
102		* The number of elements in the priority queue.
#	Line 92 | Line 113 | public class PriorityQueue<E> extends Ab
113		* The number of times this priority queue has been
114		* <i>structurally modified</i>.  See AbstractList for gory details.
115		*/
116	<	private transient int modCount = 0;
116	>	transient int modCount = 0; // non-private to simplify nested class access
117
118		/**
119	<	* Creates a <tt>PriorityQueue</tt> with the default initial
119	>	* Creates a {@code PriorityQueue} with the default initial
120		* capacity (11) that orders its elements according to their
121		* {@linkplain Comparable natural ordering}.
122		*/
#	Line 104 | Line 125 | public class PriorityQueue<E> extends Ab
125		}
126
127		/**
128	<	* Creates a <tt>PriorityQueue</tt> with the specified initial
128	>	* Creates a {@code PriorityQueue} with the specified initial
129		* capacity that orders its elements according to their
130		* {@linkplain Comparable natural ordering}.
131		*
132		* @param initialCapacity the initial capacity for this priority queue
133	<	* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less
134	<	* than 1
133	>	* @throws IllegalArgumentException if {@code initialCapacity} is less
134	>	*         than 1
135		*/
136		public PriorityQueue(int initialCapacity) {
137		this(initialCapacity, null);
138		}
139
140		/**
141	<	* Creates a <tt>PriorityQueue</tt> with the specified initial capacity
141	>	* Creates a {@code PriorityQueue} with the specified initial capacity
142		* that orders its elements according to the specified comparator.
143		*
144		* @param  initialCapacity the initial capacity for this priority queue
145	<	* @param  comparator the comparator that will be used to order
146	<	*         this priority queue.  If <tt>null</tt>, the <i>natural
147	<	*         ordering</i> of the elements will be used.
148	<	* @throws IllegalArgumentException if <tt>initialCapacity</tt> is
145	>	* @param  comparator the comparator that will be used to order this
146	>	*         priority queue.  If {@code null}, the {@linkplain Comparable
147	>	*         natural ordering} of the elements will be used.
148	>	* @throws IllegalArgumentException if {@code initialCapacity} is
149		*         less than 1
150		*/
151		public PriorityQueue(int initialCapacity,
#	Line 138 | Line 159 | public class PriorityQueue<E> extends Ab
159		}
160
161		/**
162	<	* Creates a <tt>PriorityQueue</tt> containing the elements in the
163	<	* specified collection.   If the specified collection is an
164	<	* instance of a {@link java.util.SortedSet} or is another
165	<	* <tt>PriorityQueue</tt>, the priority queue will be ordered
166	<	* according to the same ordering.  Otherwise, this priority queue
167	<	* will be ordered according to the natural ordering of its elements.
162	>	* Creates a {@code PriorityQueue} containing the elements in the
163	>	* specified collection.  If the specified collection is an instance of
164	>	* a {@link SortedSet} or is another {@code PriorityQueue}, this
165	>	* priority queue will be ordered according to the same ordering.
166	>	* Otherwise, this priority queue will be ordered according to the
167	>	* {@linkplain Comparable natural ordering} of its elements.
168		*
169		* @param  c the collection whose elements are to be placed
170		*         into this priority queue
#	Line 153 | Line 174 | public class PriorityQueue<E> extends Ab
174		* @throws NullPointerException if the specified collection or any
175		*         of its elements are null
176		*/
177	+	@SuppressWarnings("unchecked")
178		public PriorityQueue(Collection<? extends E> c) {
179	<	initFromCollection(c);
180	<	if (c instanceof SortedSet)
181	<	comparator = (Comparator<? super E>)
182	<	((SortedSet<? extends E>)c).comparator();
183	<	else if (c instanceof PriorityQueue)
184	<	comparator = (Comparator<? super E>)
185	<	((PriorityQueue<? extends E>)c).comparator();
179	>	if (c instanceof SortedSet<?>) {
180	>	SortedSet<? extends E> ss = (SortedSet<? extends E>) c;
181	>	this.comparator = (Comparator<? super E>) ss.comparator();
182	>	initElementsFromCollection(ss);
183	>	}
184	>	else if (c instanceof PriorityQueue<?>) {
185	>	PriorityQueue<? extends E> pq = (PriorityQueue<? extends E>) c;
186	>	this.comparator = (Comparator<? super E>) pq.comparator();
187	>	initFromPriorityQueue(pq);
188	>	}
189		else {
190	<	comparator = null;
191	<	heapify();
190	>	this.comparator = null;
191	>	initFromCollection(c);
192		}
193		}
194
195		/**
196	<	* Creates a <tt>PriorityQueue</tt> containing the elements in the
196	>	* Creates a {@code PriorityQueue} containing the elements in the
197		* specified priority queue.  This priority queue will be
198		* ordered according to the same ordering as the given priority
199		* queue.
200		*
201		* @param  c the priority queue whose elements are to be placed
202		*         into this priority queue
203	<	* @throws ClassCastException if elements of <tt>c</tt> cannot be
204	<	*         compared to one another according to <tt>c</tt>'s
203	>	* @throws ClassCastException if elements of {@code c} cannot be
204	>	*         compared to one another according to {@code c}'s
205		*         ordering
206		* @throws NullPointerException if the specified priority queue or any
207		*         of its elements are null
208		*/
209	+	@SuppressWarnings("unchecked")
210		public PriorityQueue(PriorityQueue<? extends E> c) {
211	<	comparator = (Comparator<? super E>)c.comparator();
212	<	initFromCollection(c);
211	>	this.comparator = (Comparator<? super E>) c.comparator();
212	>	initFromPriorityQueue(c);
213		}
214
215		/**
216	<	* Creates a <tt>PriorityQueue</tt> containing the elements in the
217	<	* specified sorted set.  This priority queue will be ordered
216	>	* Creates a {@code PriorityQueue} containing the elements in the
217	>	* specified sorted set.   This priority queue will be ordered
218		* according to the same ordering as the given sorted set.
219		*
220		* @param  c the sorted set whose elements are to be placed
221	<	*         into this priority queue.
221	>	*         into this priority queue
222		* @throws ClassCastException if elements of the specified sorted
223		*         set cannot be compared to one another according to the
224		*         sorted set's ordering
225		* @throws NullPointerException if the specified sorted set or any
226		*         of its elements are null
227		*/
228	+	@SuppressWarnings("unchecked")
229		public PriorityQueue(SortedSet<? extends E> c) {
230	<	comparator = (Comparator<? super E>)c.comparator();
231	<	initFromCollection(c);
230	>	this.comparator = (Comparator<? super E>) c.comparator();
231	>	initElementsFromCollection(c);
232		}
233
234	<	/**
235	<	* Initialize queue array with elements from the given Collection.
236	<	* @param c the collection
237	<	*/
238	<	private void initFromCollection(Collection<? extends E> c) {
234	>	private void initFromPriorityQueue(PriorityQueue<? extends E> c) {
235	>	if (c.getClass() == PriorityQueue.class) {
236	>	this.queue = c.toArray();
237	>	this.size = c.size();
238	>	} else {
239	>	initFromCollection(c);
240	>	}
241	>	}
242	>
243	>	private void initElementsFromCollection(Collection<? extends E> c) {
244		Object[] a = c.toArray();
245		// If c.toArray incorrectly doesn't return Object[], copy it.
246		if (a.getClass() != Object[].class)
247		a = Arrays.copyOf(a, a.length, Object[].class);
248	<	queue = a;
249	<	size = a.length;
248	>	int len = a.length;
249	>	if (len == 1 || this.comparator != null)
250	>	for (int i = 0; i < len; i++)
251	>	if (a[i] == null)
252	>	throw new NullPointerException();
253	>	this.queue = a;
254	>	this.size = a.length;
255	>	}
256	>
257	>	/**
258	>	* Initializes queue array with elements from the given Collection.
259	>	*
260	>	* @param c the collection
261	>	*/
262	>	private void initFromCollection(Collection<? extends E> c) {
263	>	initElementsFromCollection(c);
264	>	heapify();
265		}
266
267		/**
268	+	* The maximum size of array to allocate.
269	+	* Some VMs reserve some header words in an array.
270	+	* Attempts to allocate larger arrays may result in
271	+	* OutOfMemoryError: Requested array size exceeds VM limit
272	+	*/
273	+	private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
274	+
275	+	/**
276		* Increases the capacity of the array.
277		*
278		* @param minCapacity the desired minimum capacity
279		*/
280		private void grow(int minCapacity) {
281	<	if (minCapacity < 0) // overflow
227	<	throw new OutOfMemoryError();
228	<	int oldCapacity = queue.length;
281	>	int oldCapacity = queue.length;
282		// Double size if small; else grow by 50%
283	<	int newCapacity = ((oldCapacity < 64)?
284	<	((oldCapacity + 1) * 2):
285	<	((oldCapacity / 2) * 3));
286	<	if (newCapacity < 0) // overflow
287	<	newCapacity = Integer.MAX_VALUE;
288	<	if (newCapacity < minCapacity)
236	<	newCapacity = minCapacity;
283	>	int newCapacity = oldCapacity + ((oldCapacity < 64) ?
284	>	(oldCapacity + 2) :
285	>	(oldCapacity >> 1));
286	>	// overflow-conscious code
287	>	if (newCapacity - MAX_ARRAY_SIZE > 0)
288	>	newCapacity = hugeCapacity(minCapacity);
289		queue = Arrays.copyOf(queue, newCapacity);
290		}
291
292	+	private static int hugeCapacity(int minCapacity) {
293	+	if (minCapacity < 0) // overflow
294	+	throw new OutOfMemoryError();
295	+	return (minCapacity > MAX_ARRAY_SIZE) ?
296	+	Integer.MAX_VALUE :
297	+	MAX_ARRAY_SIZE;
298	+	}
299	+
300		/**
301		* Inserts the specified element into this priority queue.
302		*
303	<	* @return <tt>true</tt> (as specified by {@link Collection#add})
303	>	* @return {@code true} (as specified by {@link Collection#add})
304		* @throws ClassCastException if the specified element cannot be
305		*         compared with elements currently in this priority queue
306		*         according to the priority queue's ordering
#	Line 253 | Line 313 | public class PriorityQueue<E> extends Ab
313		/**
314		* Inserts the specified element into this priority queue.
315		*
316	<	* @return <tt>true</tt> (as specified by {@link Queue#offer})
316	>	* @return {@code true} (as specified by {@link Queue#offer})
317		* @throws ClassCastException if the specified element cannot be
318		*         compared with elements currently in this priority queue
319		*         according to the priority queue's ordering
#	Line 274 | Line 334 | public class PriorityQueue<E> extends Ab
334		return true;
335		}
336
337	+	@SuppressWarnings("unchecked")
338		public E peek() {
339	<	if (size == 0)
279	<	return null;
280	<	return (E) queue[0];
339	>	return (size == 0) ? null : (E) queue[0];
340		}
341
342		private int indexOf(Object o) {
343	<	if (o != null) {
343	>	if (o != null) {
344		for (int i = 0; i < size; i++)
345		if (o.equals(queue[i]))
346		return i;
#	Line 291 | Line 350 | public class PriorityQueue<E> extends Ab
350
351		/**
352		* Removes a single instance of the specified element from this queue,
353	<	* if it is present.  More formally, removes an element <tt>e</tt> such
354	<	* that <tt>o.equals(e)</tt>, if this queue contains one or more such
355	<	* elements.  Returns true if this queue contained the specified element
356	<	* (or equivalently, if this queue changed as a result of the call).
353	>	* if it is present.  More formally, removes an element {@code e} such
354	>	* that {@code o.equals(e)}, if this queue contains one or more such
355	>	* elements.  Returns {@code true} if and only if this queue contained
356	>	* the specified element (or equivalently, if this queue changed as a
357	>	* result of the call).
358		*
359		* @param o element to be removed from this queue, if present
360	<	* @return <tt>true</tt> if this queue changed as a result of the call
360	>	* @return {@code true} if this queue changed as a result of the call
361		*/
362		public boolean remove(Object o) {
363	<	int i = indexOf(o);
364	<	if (i == -1)
365	<	return false;
366	<	else {
367	<	removeAt(i);
368	<	return true;
369	<	}
363	>	int i = indexOf(o);
364	>	if (i == -1)
365	>	return false;
366	>	else {
367	>	removeAt(i);
368	>	return true;
369	>	}
370		}
371
372		/**
#	Line 314 | Line 374 | public class PriorityQueue<E> extends Ab
374		* Needed by iterator.remove.
375		*
376		* @param o element to be removed from this queue, if present
377	<	* @return <tt>true</tt> if removed
377	>	* @return {@code true} if removed
378		*/
379		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++) {
381	>	if (o == queue[i]) {
382		removeAt(i);
383		return true;
384		}
#	Line 327 | Line 387 | public class PriorityQueue<E> extends Ab
387		}
388
389		/**
390	<	* Returns <tt>true</tt> if this queue contains the specified element.
391	<	* More formally, returns <tt>true</tt> if and only if this queue contains
392	<	* at least one element <tt>e</tt> such that <tt>o.equals(e)</tt>.
390	>	* Returns {@code true} if this queue contains the specified element.
391	>	* More formally, returns {@code true} if and only if this queue contains
392	>	* at least one element {@code e} such that {@code o.equals(e)}.
393		*
394		* @param o object to be checked for containment in this queue
395	<	* @return <tt>true</tt> if this queue contains the specified element
395	>	* @return {@code true} if this queue contains the specified element
396		*/
397		public boolean contains(Object o) {
398	<	return indexOf(o) != -1;
398	>	return indexOf(o) != -1;
399		}
400
401		/**
402	<	* Returns an array containing all of the elements in this queue,
402	>	* Returns an array containing all of the elements in this queue.
403		* The elements are in no particular order.
404		*
405		* <p>The returned array will be "safe" in that no references to it are
406	<	* maintained by this list.  (In other words, this method must allocate
406	>	* maintained by this queue.  (In other words, this method must allocate
407		* a new array).  The caller is thus free to modify the returned array.
408		*
409	+	* <p>This method acts as bridge between array-based and collection-based
410	+	* APIs.
411	+	*
412		* @return an array containing all of the elements in this queue
413		*/
414		public Object[] toArray() {
#	Line 353 | Line 416 | public class PriorityQueue<E> extends Ab
416		}
417
418		/**
419	<	* Returns an array containing all of the elements in this queue.
420	<	* The elements are in no particular order.  The runtime type of
421	<	* the returned array is that of the specified array.  If the queue
422	<	* fits in the specified array, it is returned therein.
423	<	* Otherwise, a new array is allocated with the runtime type of
424	<	* the specified array and the size of this queue.
419	>	* Returns an array containing all of the elements in this queue; the
420	>	* runtime type of the returned array is that of the specified array.
421	>	* The returned array elements are in no particular order.
422	>	* If the queue fits in the specified array, it is returned therein.
423	>	* Otherwise, a new array is allocated with the runtime type of the
424	>	* specified array and the size of this queue.
425		*
426		* <p>If the queue fits in the specified array with room to spare
427		* (i.e., the array has more elements than the queue), the element in
428		* the array immediately following the end of the collection is set to
429	<	* <tt>null</tt>.  (This is useful in determining the length of the
430	<	* queue <i>only</i> if the caller knows that the queue does not contain
431	<	* any null elements.)
429	>	* {@code null}.
430	>	*
431	>	* <p>Like the {@link #toArray()} method, this method acts as bridge between
432	>	* array-based and collection-based APIs.  Further, this method allows
433	>	* precise control over the runtime type of the output array, and may,
434	>	* under certain circumstances, be used to save allocation costs.
435	>	*
436	>	* <p>Suppose {@code x} is a queue known to contain only strings.
437	>	* The following code can be used to dump the queue into a newly
438	>	* allocated array of {@code String}:
439	>	*
440	>	*  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
441	>	*
442	>	* Note that {@code toArray(new Object[0])} is identical in function to
443	>	* {@code toArray()}.
444		*
445		* @param a the array into which the elements of the queue are to
446		*          be stored, if it is big enough; otherwise, a new array of the
447		*          same runtime type is allocated for this purpose.
448	<	* @return an array containing the elements of the queue
448	>	* @return an array containing all of the elements in this queue
449		* @throws ArrayStoreException if the runtime type of the specified array
450		*         is not a supertype of the runtime type of every element in
451		*         this queue
452		* @throws NullPointerException if the specified array is null
453		*/
454	+	@SuppressWarnings("unchecked")
455		public <T> T[] toArray(T[] a) {
456	+	final int size = this.size;
457		if (a.length < size)
458		// Make a new array of a's runtime type, but my contents:
459		return (T[]) Arrays.copyOf(queue, size, a.getClass());
460	<	System.arraycopy(queue, 0, a, 0, size);
460	>	System.arraycopy(queue, 0, a, 0, size);
461		if (a.length > size)
462		a[size] = null;
463		return a;
#	Line 419 | Line 496 | public class PriorityQueue<E> extends Ab
496		* after we've completed the "normal" iteration.
497		*
498		* We expect that most iterations, even those involving removals,
499	<	* will not use need to store elements in this field.
499	>	* will not need to store elements in this field.
500		*/
501		private ArrayDeque<E> forgetMeNot = null;
502
#	Line 431 | Line 508 | public class PriorityQueue<E> extends Ab
508
509		/**
510		* The modCount value that the iterator believes that the backing
511	<	* List should have.  If this expectation is violated, the iterator
511	>	* Queue should have.  If this expectation is violated, the iterator
512		* has detected concurrent modification.
513		*/
514		private int expectedModCount = modCount;
#	Line 441 | Line 518 | public class PriorityQueue<E> extends Ab
518		(forgetMeNot != null && !forgetMeNot.isEmpty());
519		}
520
521	+	@SuppressWarnings("unchecked")
522		public E next() {
523		if (expectedModCount != modCount)
524		throw new ConcurrentModificationException();
#	Line 458 | Line 536 | public class PriorityQueue<E> extends Ab
536		public void remove() {
537		if (expectedModCount != modCount)
538		throw new ConcurrentModificationException();
461	–	if (lastRet == -1 && lastRetElt == null)
462	–	throw new IllegalStateException();
539		if (lastRet != -1) {
540		E moved = PriorityQueue.this.removeAt(lastRet);
541		lastRet = -1;
#	Line 470 | Line 546 | public class PriorityQueue<E> extends Ab
546		forgetMeNot = new ArrayDeque<E>();
547		forgetMeNot.add(moved);
548		}
549	<	} else {
549	>	} else if (lastRetElt != null) {
550		PriorityQueue.this.removeEq(lastRetElt);
551		lastRetElt = null;
552	+	} else {
553	+	throw new IllegalStateException();
554		}
555		expectedModCount = modCount;
556		}
479	–
557		}
558
559		public int size() {
#	Line 494 | Line 571 | public class PriorityQueue<E> extends Ab
571		size = 0;
572		}
573
574	+	@SuppressWarnings("unchecked")
575		public E poll() {
576		if (size == 0)
577		return null;
578		int s = --size;
579		modCount++;
580	<	E result = (E)queue[0];
581	<	E x = (E)queue[s];
580	>	E result = (E) queue[0];
581	>	E x = (E) queue[s];
582		queue[s] = null;
583		if (s != 0)
584		siftDown(0, x);
#	Line 517 | Line 595 | public class PriorityQueue<E> extends Ab
595		* i.  Under these circumstances, this method returns the element
596		* that was previously at the end of the list and is now at some
597		* position before i. This fact is used by iterator.remove so as to
598	<	* avoid missing traverseing elements.
598	>	* avoid missing traversing elements.
599		*/
600	+	@SuppressWarnings("unchecked")
601		private E removeAt(int i) {
602	<	assert i >= 0 && i < size;
602	>	// assert i >= 0 && i < size;
603		modCount++;
604		int s = --size;
605		if (s == i) // removed last element
#	Line 557 | Line 636 | public class PriorityQueue<E> extends Ab
636		siftUpComparable(k, x);
637		}
638
639	+	@SuppressWarnings("unchecked")
640		private void siftUpComparable(int k, E x) {
641		Comparable<? super E> key = (Comparable<? super E>) x;
642		while (k > 0) {
643		int parent = (k - 1) >>> 1;
644		Object e = queue[parent];
645	<	if (key.compareTo((E)e) >= 0)
645	>	if (key.compareTo((E) e) >= 0)
646		break;
647		queue[k] = e;
648		k = parent;
#	Line 570 | Line 650 | public class PriorityQueue<E> extends Ab
650		queue[k] = key;
651		}
652
653	+	@SuppressWarnings("unchecked")
654		private void siftUpUsingComparator(int k, E x) {
655		while (k > 0) {
656		int parent = (k - 1) >>> 1;
657		Object e = queue[parent];
658	<	if (comparator.compare(x, (E)e) >= 0)
658	>	if (comparator.compare(x, (E) e) >= 0)
659		break;
660		queue[k] = e;
661		k = parent;
#	Line 597 | Line 678 | public class PriorityQueue<E> extends Ab
678		siftDownComparable(k, x);
679		}
680
681	+	@SuppressWarnings("unchecked")
682		private void siftDownComparable(int k, E x) {
683		Comparable<? super E> key = (Comparable<? super E>)x;
684		int half = size >>> 1;        // loop while a non-leaf
#	Line 605 | Line 687 | public class PriorityQueue<E> extends Ab
687		Object c = queue[child];
688		int right = child + 1;
689		if (right < size &&
690	<	((Comparable<? super E>)c).compareTo((E)queue[right]) > 0)
690	>	((Comparable<? super E>) c).compareTo((E) queue[right]) > 0)
691		c = queue[child = right];
692	<	if (key.compareTo((E)c) <= 0)
692	>	if (key.compareTo((E) c) <= 0)
693		break;
694		queue[k] = c;
695		k = child;
#	Line 615 | Line 697 | public class PriorityQueue<E> extends Ab
697		queue[k] = key;
698		}
699
700	+	@SuppressWarnings("unchecked")
701		private void siftDownUsingComparator(int k, E x) {
702		int half = size >>> 1;
703		while (k < half) {
#	Line 622 | Line 705 | public class PriorityQueue<E> extends Ab
705		Object c = queue[child];
706		int right = child + 1;
707		if (right < size &&
708	<	comparator.compare((E)c, (E)queue[right]) > 0)
708	>	comparator.compare((E) c, (E) queue[right]) > 0)
709		c = queue[child = right];
710	<	if (comparator.compare(x, (E)c) <= 0)
710	>	if (comparator.compare(x, (E) c) <= 0)
711		break;
712		queue[k] = c;
713		k = child;
#	Line 636 | Line 719 | public class PriorityQueue<E> extends Ab
719		* Establishes the heap invariant (described above) in the entire tree,
720		* assuming nothing about the order of the elements prior to the call.
721		*/
722	+	@SuppressWarnings("unchecked")
723		private void heapify() {
724		for (int i = (size >>> 1) - 1; i >= 0; i--)
725	<	siftDown(i, (E)queue[i]);
725	>	siftDown(i, (E) queue[i]);
726		}
727
728		/**
729		* Returns the comparator used to order the elements in this
730	<	* queue, or <tt>null</tt> if this queue is sorted according to
730	>	* queue, or {@code null} if this queue is sorted according to
731		* the {@linkplain Comparable natural ordering} of its elements.
732		*
733		* @return the comparator used to order this queue, or
734	<	*         <tt>null</tt> if this queue is sorted according to the
735	<	*         natural ordering of its elements.
734	>	*         {@code null} if this queue is sorted according to the
735	>	*         natural ordering of its elements
736		*/
737		public Comparator<? super E> comparator() {
738		return comparator;
739		}
740
741		/**
742	<	* Save the state of the instance to a stream (that
659	<	* is, serialize it).
742	>	* Saves this queue to a stream (that is, serializes it).
743		*
744		* @serialData The length of the array backing the instance is
745	<	* emitted (int), followed by all of its elements (each an
746	<	* <tt>Object</tt>) in the proper order.
745	>	*             emitted (int), followed by all of its elements
746	>	*             (each an {@code Object}) in the proper order.
747		* @param s the stream
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.
673	<	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		*/
768		private void readObject(java.io.ObjectInputStream s)
#	Line 687 | Line 770 | public class PriorityQueue<E> extends Ab
770		// Read in size, and any hidden stuff
771		s.defaultReadObject();
772
773	<	// Read in array length and allocate array
774	<	int arrayLength = s.readInt();
692	<	queue = new Object[arrayLength];
693	<
694	<	// Read in all elements in the proper order.
695	<	for (int i=0; i<size; i++)
696	<	queue[i] = (E) s.readObject();
697	<	}
773	>	// Read in (and discard) array length
774	>	s.readInt();
775
776	+	queue = new Object[size];
777	+
778	+	// Read in all elements.
779	+	for (int i = 0; i < size; i++)
780	+	queue[i] = s.readObject();
781	+
782	+	// Elements are guaranteed to be in "proper order", but the
783	+	// spec has never explained what that might be.
784	+	heapify();
785	+	}
786	+
787	+	// wrapping constructor in method avoids transient javac problems
788	+	final PriorityQueueSpliterator<E> spliterator(int origin, int fence,
789	+	int expectedModCount) {
790	+	return new PriorityQueueSpliterator<E>(this, origin, fence,
791	+	expectedModCount);
792	+	}
793	+
794	+	public Stream<E> stream() {
795	+	int flags = Streams.STREAM_IS_SIZED;
796	+	return Streams.stream
797	+	(() -> spliterator(0, size, modCount), flags);
798	+	}
799	+	public Stream<E> parallelStream() {
800	+	int flags = Streams.STREAM_IS_SIZED;
801	+	return Streams.parallelStream
802	+	(() -> spliterator(0, size, modCount), flags);
803	+	}
804	+
805	+	/** Index-based split-by-two Spliterator */
806	+	static final class PriorityQueueSpliterator<E> implements Spliterator<E> {
807	+	private final PriorityQueue<E> pq;
808	+	private int index;           // current index, modified on advance/split
809	+	private final int fence;     // one past last index
810	+	private final int expectedModCount; // for comodification checks
811	+
812	+	/** Create new spliterator covering the given  range */
813	+	PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
814	+	int expectedModCount) {
815	+	this.pq = pq; this.index = origin; this.fence = fence;
816	+	this.expectedModCount = expectedModCount;
817	+	}
818	+
819	+	public PriorityQueueSpliterator<E> trySplit() {
820	+	int lo = index, mid = (lo + fence) >>> 1;
821	+	return (lo >= mid) ? null :
822	+	new PriorityQueueSpliterator<E>(pq, lo, index = mid,
823	+	expectedModCount);
824	+	}
825	+
826	+	public void forEach(Consumer<? super E> block) {
827	+	Object[] a; int i, hi; // hoist accesses and checks from loop
828	+	if (block == null)
829	+	throw new NullPointerException();
830	+	if ((a = pq.queue).length >= (hi = fence) &&
831	+	(i = index) >= 0 && i < hi) {
832	+	index = hi;
833	+	do {
834	+	@SuppressWarnings("unchecked") E e = (E) a[i];
835	+	block.accept(e);
836	+	} while (++i < hi);
837	+	if (pq.modCount != expectedModCount)
838	+	throw new ConcurrentModificationException();
839	+	}
840	+	}
841	+
842	+	public boolean tryAdvance(Consumer<? super E> block) {
843	+	if (index >= 0 && index < fence) {
844	+	@SuppressWarnings("unchecked") E e =
845	+	(E)pq.queue[index++];
846	+	block.accept(e);
847	+	if (pq.modCount != expectedModCount)
848	+	throw new ConcurrentModificationException();
849	+	return true;
850	+	}
851	+	return false;
852	+	}
853	+
854	+	public long estimateSize() { return (long)(fence - index); }
855	+	public boolean hasExactSize() { return true; }
856	+	public boolean hasExactSplits() { return true; }
857	+	}
858		}

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