ViewVC Help

View File | Revision Log | Show Annotations | Download File | Root Listing

root/jsr166/jsr166/src/main/java/util/PriorityQueue.java

Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.63 by jsr166, Tue Mar 7 07:11:39 2006 UTC vs.
Revision 1.96 by jsr166, Thu May 2 06:02:17 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 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	+	import java.util.function.Consumer;
28	+	import java.util.stream.Stream;
29
30		/**
31		* An unbounded priority {@linkplain Queue queue} based on a priority heap.
#	Line 38 | Line 58 | package java.util;
58		* the priority queue in any particular order. If you need ordered
59		* traversal, consider using {@code Arrays.sort(pq.toArray())}.
60		*
61	<	* <p> <strong>Note that this implementation is not synchronized.</strong>
61	>	* <p><strong>Note that this implementation is not synchronized.</strong>
62		* Multiple threads should not access a {@code PriorityQueue}
63		* instance concurrently if any of the threads modifies the queue.
64		* Instead, use the thread-safe {@link
#	Line 52 | Line 72 | package java.util;
72		* ({@code peek}, {@code element}, and {@code size}).
73		*
74		* <p>This class is a member of the
75	<	* <a href="{@docRoot}/../guide/collections/index.html">
75	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
76		* Java Collections Framework</a>.
77		*
78		* @since 1.5
59	–	* @version %I%, %G%
79		* @author Josh Bloch, Doug Lea
80		* @param <E> the type of elements held in this collection
81		*/
#	Line 75 | Line 94 | public class PriorityQueue<E> extends Ab
94		* heap and each descendant d of n, n <= d.  The element with the
95		* lowest value is in queue[0], assuming the queue is nonempty.
96		*/
97	<	private transient Object[] queue;
97	>	transient Object[] queue; // non-private to simplify nested class access
98
99		/**
100		* The number of elements in the priority queue.
#	Line 92 | Line 111 | public class PriorityQueue<E> extends Ab
111		* The number of times this priority queue has been
112		* <i>structurally modified</i>.  See AbstractList for gory details.
113		*/
114	<	private transient int modCount = 0;
114	>	transient int modCount = 0; // non-private to simplify nested class access
115
116		/**
117		* Creates a {@code PriorityQueue} with the default initial
#	Line 153 | Line 172 | public class PriorityQueue<E> extends Ab
172		* @throws NullPointerException if the specified collection or any
173		*         of its elements are null
174		*/
175	+	@SuppressWarnings("unchecked")
176		public PriorityQueue(Collection<? extends E> c) {
177	<	initFromCollection(c);
178	<	if (c instanceof SortedSet)
179	<	comparator = (Comparator<? super E>)
180	<	((SortedSet<? extends E>)c).comparator();
181	<	else if (c instanceof PriorityQueue)
182	<	comparator = (Comparator<? super E>)
183	<	((PriorityQueue<? extends E>)c).comparator();
177	>	if (c instanceof SortedSet<?>) {
178	>	SortedSet<? extends E> ss = (SortedSet<? extends E>) c;
179	>	this.comparator = (Comparator<? super E>) ss.comparator();
180	>	initElementsFromCollection(ss);
181	>	}
182	>	else if (c instanceof PriorityQueue<?>) {
183	>	PriorityQueue<? extends E> pq = (PriorityQueue<? extends E>) c;
184	>	this.comparator = (Comparator<? super E>) pq.comparator();
185	>	initFromPriorityQueue(pq);
186	>	}
187		else {
188	<	comparator = null;
189	<	heapify();
188	>	this.comparator = null;
189	>	initFromCollection(c);
190		}
191		}
192
#	Line 181 | Line 204 | public class PriorityQueue<E> extends Ab
204		* @throws NullPointerException if the specified priority queue or any
205		*         of its elements are null
206		*/
207	+	@SuppressWarnings("unchecked")
208		public PriorityQueue(PriorityQueue<? extends E> c) {
209	<	comparator = (Comparator<? super E>)c.comparator();
210	<	initFromCollection(c);
209	>	this.comparator = (Comparator<? super E>) c.comparator();
210	>	initFromPriorityQueue(c);
211		}
212
213		/**
#	Line 199 | Line 223 | public class PriorityQueue<E> extends Ab
223		* @throws NullPointerException if the specified sorted set or any
224		*         of its elements are null
225		*/
226	+	@SuppressWarnings("unchecked")
227		public PriorityQueue(SortedSet<? extends E> c) {
228	<	comparator = (Comparator<? super E>)c.comparator();
229	<	initFromCollection(c);
228	>	this.comparator = (Comparator<? super E>) c.comparator();
229	>	initElementsFromCollection(c);
230	>	}
231	>
232	>	private void initFromPriorityQueue(PriorityQueue<? extends E> c) {
233	>	if (c.getClass() == PriorityQueue.class) {
234	>	this.queue = c.toArray();
235	>	this.size = c.size();
236	>	} else {
237	>	initFromCollection(c);
238	>	}
239	>	}
240	>
241	>	private void initElementsFromCollection(Collection<? extends E> c) {
242	>	Object[] a = c.toArray();
243	>	// If c.toArray incorrectly doesn't return Object[], copy it.
244	>	if (a.getClass() != Object[].class)
245	>	a = Arrays.copyOf(a, a.length, Object[].class);
246	>	int len = a.length;
247	>	if (len == 1 || this.comparator != null)
248	>	for (int i = 0; i < len; i++)
249	>	if (a[i] == null)
250	>	throw new NullPointerException();
251	>	this.queue = a;
252	>	this.size = a.length;
253		}
254
255		/**
#	Line 210 | Line 258 | public class PriorityQueue<E> extends Ab
258		* @param c the collection
259		*/
260		private void initFromCollection(Collection<? extends E> c) {
261	<	Object[] a = c.toArray();
262	<	// 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;
261	>	initElementsFromCollection(c);
262	>	heapify();
263		}
264
265		/**
266	+	* The maximum size of array to allocate.
267	+	* Some VMs reserve some header words in an array.
268	+	* Attempts to allocate larger arrays may result in
269	+	* OutOfMemoryError: Requested array size exceeds VM limit
270	+	*/
271	+	private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
272	+
273	+	/**
274		* Increases the capacity of the array.
275		*
276		* @param minCapacity the desired minimum capacity
277		*/
278		private void grow(int minCapacity) {
279	<	if (minCapacity < 0) // overflow
228	<	throw new OutOfMemoryError();
229	<	int oldCapacity = queue.length;
279	>	int oldCapacity = queue.length;
280		// Double size if small; else grow by 50%
281	<	int newCapacity = ((oldCapacity < 64)?
282	<	((oldCapacity + 1) * 2):
283	<	((oldCapacity / 2) * 3));
284	<	if (newCapacity < 0) // overflow
285	<	newCapacity = Integer.MAX_VALUE;
286	<	if (newCapacity < minCapacity)
237	<	newCapacity = minCapacity;
281	>	int newCapacity = oldCapacity + ((oldCapacity < 64) ?
282	>	(oldCapacity + 2) :
283	>	(oldCapacity >> 1));
284	>	// overflow-conscious code
285	>	if (newCapacity - MAX_ARRAY_SIZE > 0)
286	>	newCapacity = hugeCapacity(minCapacity);
287		queue = Arrays.copyOf(queue, newCapacity);
288		}
289
290	+	private static int hugeCapacity(int minCapacity) {
291	+	if (minCapacity < 0) // overflow
292	+	throw new OutOfMemoryError();
293	+	return (minCapacity > MAX_ARRAY_SIZE) ?
294	+	Integer.MAX_VALUE :
295	+	MAX_ARRAY_SIZE;
296	+	}
297	+
298		/**
299		* Inserts the specified element into this priority queue.
300		*
#	Line 275 | Line 332 | public class PriorityQueue<E> extends Ab
332		return true;
333		}
334
335	+	@SuppressWarnings("unchecked")
336		public E peek() {
337	<	if (size == 0)
280	<	return null;
281	<	return (E) queue[0];
337	>	return (size == 0) ? null : (E) queue[0];
338		}
339
340		private int indexOf(Object o) {
341	<	if (o != null) {
341	>	if (o != null) {
342		for (int i = 0; i < size; i++)
343		if (o.equals(queue[i]))
344		return i;
#	Line 302 | Line 358 | public class PriorityQueue<E> extends Ab
358		* @return {@code true} if this queue changed as a result of the call
359		*/
360		public boolean remove(Object o) {
361	<	int i = indexOf(o);
362	<	if (i == -1)
363	<	return false;
364	<	else {
365	<	removeAt(i);
366	<	return true;
367	<	}
361	>	int i = indexOf(o);
362	>	if (i == -1)
363	>	return false;
364	>	else {
365	>	removeAt(i);
366	>	return true;
367	>	}
368		}
369
370		/**
#	Line 319 | Line 375 | public class PriorityQueue<E> extends Ab
375		* @return {@code true} if removed
376		*/
377		boolean removeEq(Object o) {
378	<	for (int i = 0; i < size; i++) {
379	<	if (o == queue[i]) {
378	>	for (int i = 0; i < size; i++) {
379	>	if (o == queue[i]) {
380		removeAt(i);
381		return true;
382		}
#	Line 337 | Line 393 | public class PriorityQueue<E> extends Ab
393		* @return {@code true} if this queue contains the specified element
394		*/
395		public boolean contains(Object o) {
396	<	return indexOf(o) != -1;
396	>	return indexOf(o) != -1;
397		}
398
399		/**
#	Line 375 | Line 431 | public class PriorityQueue<E> extends Ab
431		* precise control over the runtime type of the output array, and may,
432		* under certain circumstances, be used to save allocation costs.
433		*
434	<	* <p>Suppose <tt>x</tt> is a queue known to contain only strings.
434	>	* <p>Suppose {@code x} is a queue known to contain only strings.
435		* The following code can be used to dump the queue into a newly
436	<	* allocated array of <tt>String</tt>:
436	>	* allocated array of {@code String}:
437		*
438	<	* <pre>
383	<	*     String[] y = x.toArray(new String[0]);</pre>
438	>	*  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
439		*
440	<	* Note that <tt>toArray(new Object[0])</tt> is identical in function to
441	<	* <tt>toArray()</tt>.
440	>	* Note that {@code toArray(new Object[0])} is identical in function to
441	>	* {@code toArray()}.
442		*
443		* @param a the array into which the elements of the queue are to
444		*          be stored, if it is big enough; otherwise, a new array of the
#	Line 394 | Line 449 | public class PriorityQueue<E> extends Ab
449		*         this queue
450		* @throws NullPointerException if the specified array is null
451		*/
452	+	@SuppressWarnings("unchecked")
453		public <T> T[] toArray(T[] a) {
454	+	final int size = this.size;
455		if (a.length < size)
456		// Make a new array of a's runtime type, but my contents:
457		return (T[]) Arrays.copyOf(queue, size, a.getClass());
458	<	System.arraycopy(queue, 0, a, 0, size);
458	>	System.arraycopy(queue, 0, a, 0, size);
459		if (a.length > size)
460		a[size] = null;
461		return a;
#	Line 459 | Line 516 | public class PriorityQueue<E> extends Ab
516		(forgetMeNot != null && !forgetMeNot.isEmpty());
517		}
518
519	+	@SuppressWarnings("unchecked")
520		public E next() {
521		if (expectedModCount != modCount)
522		throw new ConcurrentModificationException();
#	Line 483 | Line 541 | public class PriorityQueue<E> extends Ab
541		cursor--;
542		else {
543		if (forgetMeNot == null)
544	<	forgetMeNot = new ArrayDeque<E>();
544	>	forgetMeNot = new ArrayDeque<>();
545		forgetMeNot.add(moved);
546		}
547		} else if (lastRetElt != null) {
#	Line 491 | Line 549 | public class PriorityQueue<E> extends Ab
549		lastRetElt = null;
550		} else {
551		throw new IllegalStateException();
552	<	}
552	>	}
553		expectedModCount = modCount;
554		}
555		}
#	Line 511 | Line 569 | public class PriorityQueue<E> extends Ab
569		size = 0;
570		}
571
572	+	@SuppressWarnings("unchecked")
573		public E poll() {
574		if (size == 0)
575		return null;
#	Line 536 | Line 595 | public class PriorityQueue<E> extends Ab
595		* position before i. This fact is used by iterator.remove so as to
596		* avoid missing traversing elements.
597		*/
598	+	@SuppressWarnings("unchecked")
599		private E removeAt(int i) {
600	<	assert i >= 0 && i < size;
600	>	// assert i >= 0 && i < size;
601		modCount++;
602		int s = --size;
603		if (s == i) // removed last element
#	Line 574 | Line 634 | public class PriorityQueue<E> extends Ab
634		siftUpComparable(k, x);
635		}
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) {
#	Line 587 | Line 648 | public class PriorityQueue<E> extends Ab
648		queue[k] = key;
649		}
650
651	+	@SuppressWarnings("unchecked")
652		private void siftUpUsingComparator(int k, E x) {
653		while (k > 0) {
654		int parent = (k - 1) >>> 1;
#	Line 614 | Line 676 | public class PriorityQueue<E> extends Ab
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
#	Line 632 | Line 695 | public class PriorityQueue<E> extends Ab
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) {
#	Line 653 | Line 717 | public class PriorityQueue<E> extends Ab
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]);
#	Line 672 | Line 737 | public class PriorityQueue<E> extends Ab
737		}
738
739		/**
740	<	* Saves the state of the instance to a stream (that
676	<	* 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
#	Line 681 | Line 745 | public class PriorityQueue<E> extends Ab
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
752		// Write out array length, for compatibility with 1.5 version
753		s.writeInt(Math.max(2, size + 1));
754
755	<	// Write out all elements in the proper order.
755	>	// Write out all elements in the "proper order".
756		for (int i = 0; i < size; i++)
757		s.writeObject(queue[i]);
758		}
#	Line 707 | Line 771 | public class PriorityQueue<E> extends Ab
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 in the proper order.
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();
783	+	}
784	+
785	+	public Spliterator<E> spliterator() {
786	+	return new PriorityQueueSpliterator<E>(this, 0, -1, 0);
787	+	}
788	+
789	+	/**
790	+	* This is very similar to ArrayList Spliterator, except for extra
791	+	* null checks.
792	+	*/
793	+	static final class PriorityQueueSpliterator<E> implements Spliterator<E> {
794	+	private final PriorityQueue<E> pq;
795	+	private int index;            // current index, modified on advance/split
796	+	private int fence;            // -1 until first use
797	+	private int expectedModCount; // initialized when fence set
798	+
799	+	/** Creates new spliterator covering the given range */
800	+	PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
801	+	int expectedModCount) {
802	+	this.pq = pq;
803	+	this.index = origin;
804	+	this.fence = fence;
805	+	this.expectedModCount = expectedModCount;
806	+	}
807	+
808	+	private int getFence() { // initialize fence to size on first use
809	+	int hi;
810	+	if ((hi = fence) < 0) {
811	+	expectedModCount = pq.modCount;
812	+	hi = fence = pq.size;
813	+	}
814	+	return hi;
815	+	}
816	+
817	+	public Spliterator<E> trySplit() {
818	+	int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
819	+	return (lo >= mid) ? null :
820	+	new PriorityQueueSpliterator<E>(pq, lo, index = mid,
821	+	expectedModCount);
822	+	}
823	+
824	+	@SuppressWarnings("unchecked")
825	+	public void forEachRemaining(Consumer<? super E> action) {
826	+	int i, hi, mc; // hoist accesses and checks from loop
827	+	PriorityQueue<E> q; Object[] a;
828	+	if (action == null)
829	+	throw new NullPointerException();
830	+	if ((q = pq) != null && (a = q.queue) != null) {
831	+	if ((hi = fence) < 0) {
832	+	mc = q.modCount;
833	+	hi = q.size;
834	+	}
835	+	else
836	+	mc = expectedModCount;
837	+	if ((i = index) >= 0 && (index = hi) <= a.length) {
838	+	for (E e;; ++i) {
839	+	if (i < hi) {
840	+	if ((e = (E) a[i]) == null) // must be CME
841	+	break;
842	+	action.accept(e);
843	+	}
844	+	else if (q.modCount != mc)
845	+	break;
846	+	else
847	+	return;
848	+	}
849	+	}
850	+	}
851	+	throw new ConcurrentModificationException();
852	+	}
853	+
854	+	public boolean tryAdvance(Consumer<? super E> action) {
855	+	int hi = getFence(), lo = index;
856	+	if (lo >= 0 && lo < hi) {
857	+	index = lo + 1;
858	+	@SuppressWarnings("unchecked") E e = (E)pq.queue[lo];
859	+	if (e == null)
860	+	throw new ConcurrentModificationException();
861	+	action.accept(e);
862	+	if (pq.modCount != expectedModCount)
863	+	throw new ConcurrentModificationException();
864	+	return true;
865	+	}
866	+	return false;
867	+	}
868	+
869	+	public long estimateSize() {
870	+	return (long) (getFence() - index);
871	+	}
872	+
873	+	public int characteristics() {
874	+	return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL;
875	+	}
876		}
877		}

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines