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Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.66 by jsr166, Sun Jan 7 07:38:27 2007 UTC vs.
Revision 1.89 by dl, Sun Feb 17 23:36:16 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 2007 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.function.Consumer;
28	+	import java.util.stream.Stream;
29	+	import java.util.stream.Streams;
30
31		/**
32		* An unbounded priority {@linkplain Queue queue} based on a priority heap.
#	Line 38 | Line 59 | package java.util;
59		* the priority queue in any particular order. If you need ordered
60		* traversal, consider using {@code Arrays.sort(pq.toArray())}.
61		*
62	<	* <p> <strong>Note that this implementation is not synchronized.</strong>
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
#	Line 56 | Line 77 | package java.util;
77		* Java Collections Framework</a>.
78		*
79		* @since 1.5
59	–	* @version %I%, %G%
80		* @author Josh Bloch, Doug Lea
81		* @param <E> the type of elements held in this collection
82		*/
#	Line 75 | 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.
#	Line 92 | 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 {@code PriorityQueue} with the default initial
#	Line 153 | 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
#	Line 181 | Line 205 | public class PriorityQueue<E> extends Ab
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		/**
#	Line 199 | Line 224 | public class PriorityQueue<E> extends Ab
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	>	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	>	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		/**
#	Line 210 | Line 259 | public class PriorityQueue<E> extends Ab
259		* @param c the collection
260		*/
261		private void initFromCollection(Collection<? extends E> c) {
262	<	Object[] a = c.toArray();
263	<	// If c.toArray incorrectly doesn't return Object[], copy it.
215	<	if (a.getClass() != Object[].class)
216	<	a = Arrays.copyOf(a, a.length, Object[].class);
217	<	queue = a;
218	<	size = a.length;
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
228	<	throw new OutOfMemoryError();
229	<	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)
237	<	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		*
#	Line 275 | Line 333 | public class PriorityQueue<E> extends Ab
333		return true;
334		}
335
336	+	@SuppressWarnings("unchecked")
337		public E peek() {
338	<	if (size == 0)
280	<	return null;
281	<	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 302 | Line 359 | public class PriorityQueue<E> extends Ab
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 319 | Line 376 | public class PriorityQueue<E> extends Ab
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 337 | Line 394 | public class PriorityQueue<E> extends Ab
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) != -1;
398		}
399
400		/**
#	Line 375 | Line 432 | public class PriorityQueue<E> extends Ab
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 <tt>x</tt> is a queue known to contain only strings.
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 <tt>String</tt>:
437	>	* allocated array of {@code String}:
438		*
439	<	* <pre>
383	<	*     String[] y = x.toArray(new String[0]);</pre>
439	>	*  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
440		*
441	<	* Note that <tt>toArray(new Object[0])</tt> is identical in function to
442	<	* <tt>toArray()</tt>.
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
#	Line 394 | Line 450 | public class PriorityQueue<E> extends Ab
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 459 | 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 483 | 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 if (lastRetElt != null) {
#	Line 491 | Line 550 | public class PriorityQueue<E> extends Ab
550		lastRetElt = null;
551		} else {
552		throw new IllegalStateException();
553	<	}
553	>	}
554		expectedModCount = modCount;
555		}
556		}
#	Line 511 | 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;
#	Line 536 | Line 596 | public class PriorityQueue<E> extends Ab
596		* position before i. This fact is used by iterator.remove so as to
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 574 | 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) {
#	Line 587 | 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;
#	Line 614 | 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 632 | 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 653 | 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]);
#	Line 672 | Line 738 | public class PriorityQueue<E> extends Ab
738		}
739
740		/**
741	<	* Saves the state of the instance to a stream (that
676	<	* is, serializes 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
#	Line 681 | Line 746 | public class PriorityQueue<E> extends Ab
746		* @param s the stream
747		*/
748		private void writeObject(java.io.ObjectOutputStream s)
749	<	throws java.io.IOException{
749	>	throws java.io.IOException {
750		// Write out element count, and any hidden stuff
751		s.defaultWriteObject();
752
#	Line 707 | Line 772 | public class PriorityQueue<E> extends Ab
772		// Read in (and discard) array length
773		s.readInt();
774
775	<	queue = new Object[size];
775	>	queue = new Object[size];
776
777		// Read in all elements.
778		for (int i = 0; i < size; i++)
779		queue[i] = s.readObject();
780
781	<	// Elements are guaranteed to be in "proper order", but the
782	<	// spec has never explained what that might be.
783	<	heapify();
781	>	// Elements are guaranteed to be in "proper order", but the
782	>	// spec has never explained what that might be.
783	>	heapify();
784	>	}
785	>
786	>	final Spliterator<E> spliterator() {
787	>	return new PriorityQueueSpliterator<E>(this, 0, -1, 0);
788	>	}
789	>
790	>	public Stream<E> stream() {
791	>	return Streams.stream(spliterator());
792	>	}
793	>
794	>	public Stream<E> parallelStream() {
795	>	return Streams.parallelStream(spliterator());
796	>	}
797	>
798	>	static final class PriorityQueueSpliterator<E> implements Spliterator<E> {
799	>	/*
800	>	* This is very similar to ArrayList Spliterator, except for
801	>	* extra null checks.
802	>	*/
803	>	private final PriorityQueue<E> pq;
804	>	private int index;            // current index, modified on advance/split
805	>	private int fence;            // -1 until first use
806	>	private int expectedModCount; // initialized when fence set
807	>
808	>	/** Create new spliterator covering the given  range */
809	>	PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
810	>	int expectedModCount) {
811	>	this.pq = pq;
812	>	this.index = origin;
813	>	this.fence = fence;
814	>	this.expectedModCount = expectedModCount;
815	>	}
816	>
817	>	private int getFence() { // initialize fence to size on first use
818	>	int hi;
819	>	if ((hi = fence) < 0) {
820	>	expectedModCount = pq.modCount;
821	>	hi = fence = pq.size;
822	>	}
823	>	return hi;
824	>	}
825	>
826	>	public PriorityQueueSpliterator<E> trySplit() {
827	>	int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
828	>	return (lo >= mid) ? null :
829	>	new PriorityQueueSpliterator<E>(pq, lo, index = mid,
830	>	expectedModCount);
831	>	}
832	>
833	>	@SuppressWarnings("unchecked")
834	>	public void forEach(Consumer<? super E> action) {
835	>	int i, hi, mc; // hoist accesses and checks from loop
836	>	PriorityQueue<E> q; Object[] a;
837	>	if (action == null)
838	>	throw new NullPointerException();
839	>	if ((q = pq) != null && (a = q.queue) != null) {
840	>	if ((hi = fence) < 0) {
841	>	mc = q.modCount;
842	>	hi = q.size;
843	>	}
844	>	else
845	>	mc = expectedModCount;
846	>	if ((i = index) >= 0 && (index = hi) <= a.length) {
847	>	for (E e;; ++i) {
848	>	if (i < hi) {
849	>	if ((e = (E) a[i]) == null) // must be CME
850	>	break;
851	>	action.accept(e);
852	>	}
853	>	else if (q.modCount != mc)
854	>	break;
855	>	else
856	>	return;
857	>	}
858	>	}
859	>	}
860	>	throw new ConcurrentModificationException();
861	>	}
862	>
863	>	public boolean tryAdvance(Consumer<? super E> action) {
864	>	int hi = getFence(), lo = index;
865	>	if (lo >= 0 && lo < hi) {
866	>	index = lo + 1;
867	>	@SuppressWarnings("unchecked") E e = (E)pq.queue[lo];
868	>	if (e == null)
869	>	throw new ConcurrentModificationException();
870	>	action.accept(e);
871	>	if (pq.modCount != expectedModCount)
872	>	throw new ConcurrentModificationException();
873	>	return true;
874	>	}
875	>	return false;
876	>	}
877	>
878	>	public long estimateSize() {
879	>	return (long) (getFence() - index);
880	>	}
881	>
882	>	public int characteristics() {
883	>	return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL;
884	>	}
885		}
886		}

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