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Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.70 by jsr166, Mon May 10 20:11:01 2010 UTC vs.
Revision 1.85 by jsr166, Sat Jan 19 18:18:10 2013 UTC

#	Line 1 | Line 1
1		/*
2	<	* Copyright 2003-2006 Sun Microsystems, Inc.  All Rights Reserved.
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		* 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.  Sun designates this
7	>	* published by the Free Software Foundation.  Oracle designates this
8		* particular file as subject to the "Classpath" exception as provided
9	<	* by Sun in the LICENSE file that accompanied this code.
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
#	Line 18 | Line 18
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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22	<	* CA 95054 USA or visit www.sun.com if you need additional information or
23	<	* have any questions.
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.stream.Stream;
28	+	import java.util.Spliterator;
29	+	import java.util.stream.Streams;
30	+	import java.util.function.Block;
31
32		/**
33		* An unbounded priority {@linkplain Queue queue} based on a priority heap.
#	Line 56 | Line 60 | package java.util;
60		* the priority queue in any particular order. If you need ordered
61		* traversal, consider using {@code Arrays.sort(pq.toArray())}.
62		*
63	<	* <p> <strong>Note that this implementation is not synchronized.</strong>
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
#	Line 92 | 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 109 | 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 {@code PriorityQueue} with the default initial
#	Line 330 | Line 334 | public class PriorityQueue<E> extends Ab
334		return true;
335		}
336
337	+	@SuppressWarnings("unchecked")
338		public E peek() {
339	<	if (size == 0)
335	<	return null;
336	<	return (E) queue[0];
339	>	return (size == 0) ? null : (E) queue[0];
340		}
341
342		private int indexOf(Object o) {
#	Line 430 | Line 433 | public class PriorityQueue<E> extends Ab
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 <tt>x</tt> is a queue known to contain only strings.
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 <tt>String</tt>:
438	>	* allocated array of {@code String}:
439		*
440	<	* <pre>
438	<	*     String[] y = x.toArray(new String[0]);</pre>
440	>	*  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
441		*
442	<	* Note that <tt>toArray(new Object[0])</tt> is identical in function to
443	<	* <tt>toArray()</tt>.
442	>	* Note that {@code toArray(new Object[0])} is identical in function to
443	>	* {@code toArray()}.
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
#	Line 449 | Line 451 | public class PriorityQueue<E> extends Ab
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());
#	Line 514 | 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 566 | 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;
#	Line 591 | Line 597 | public class PriorityQueue<E> extends Ab
597		* position before i. This fact is used by iterator.remove so as to
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 629 | 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) {
#	Line 642 | 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;
#	Line 669 | 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 687 | 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 708 | 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]);
#	Line 727 | Line 739 | public class PriorityQueue<E> extends Ab
739		}
740
741		/**
742	<	* Saves the state of the instance to a stream (that
731	<	* is, serializes 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
#	Line 736 | Line 747 | public class PriorityQueue<E> extends Ab
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
#	Line 772 | Line 783 | public class PriorityQueue<E> extends Ab
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>
807	+	implements Spliterator<E>, Iterator<E> {
808	+	private final PriorityQueue<E> pq;
809	+	private int index;           // current index, modified on advance/split
810	+	private final int fence;     // one past last index
811	+	private final int expectedModCount; // for comodification checks
812	+
813	+	/** Create new spliterator covering the given  range */
814	+	PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
815	+	int expectedModCount) {
816	+	this.pq = pq; this.index = origin; this.fence = fence;
817	+	this.expectedModCount = expectedModCount;
818	+	}
819	+
820	+	public PriorityQueueSpliterator<E> trySplit() {
821	+	int lo = index, mid = (lo + fence) >>> 1;
822	+	return (lo >= mid) ? null :
823	+	new PriorityQueueSpliterator<E>(pq, lo, index = mid,
824	+	expectedModCount);
825	+	}
826	+
827	+	public void forEach(Block<? super E> block) {
828	+	Object[] a; int i, hi; // hoist accesses and checks from loop
829	+	if (block == null)
830	+	throw new NullPointerException();
831	+	if ((a = pq.queue).length >= (hi = fence) &&
832	+	(i = index) >= 0 && i < hi) {
833	+	index = hi;
834	+	do {
835	+	@SuppressWarnings("unchecked") E e = (E) a[i];
836	+	block.accept(e);
837	+	} while (++i < hi);
838	+	if (pq.modCount != expectedModCount)
839	+	throw new ConcurrentModificationException();
840	+	}
841	+	}
842	+
843	+	public boolean tryAdvance(Block<? super E> block) {
844	+	if (index >= 0 && index < fence) {
845	+	if (pq.modCount != expectedModCount)
846	+	throw new ConcurrentModificationException();
847	+	@SuppressWarnings("unchecked") E e =
848	+	(E)pq.queue[index++];
849	+	block.accept(e);
850	+	return true;
851	+	}
852	+	return false;
853	+	}
854	+
855	+	public long estimateSize() { return (long)(fence - index); }
856	+	public boolean hasExactSize() { return true; }
857	+	public boolean hasExactSplits() { return true; }
858	+
859	+	// Iterator support
860	+	public Iterator<E> iterator() { return this; }
861	+	public void remove() { throw new UnsupportedOperationException(); }
862	+	public boolean hasNext() { return index >= 0 && index < fence; }
863	+
864	+	public E next() {
865	+	if (index < 0 || index >= fence)
866	+	throw new NoSuchElementException();
867	+	if (pq.modCount != expectedModCount)
868	+	throw new ConcurrentModificationException();
869	+	@SuppressWarnings("unchecked") E e =
870	+	(E) pq.queue[index++];
871	+	return e;
872	+	}
873	+	}
874		}

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