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

Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.86 by dl, Tue Jan 22 19:28:05 2013 UTC vs.
Revision 1.110 by jsr166, Wed Aug 24 21:46:18 2016 UTC

#	Line 1 | Line 1
1		/*
2	<	* Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
2	>	* Copyright (c) 2003, 2013, 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
#	Line 24 | Line 24
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;
27	>
28	>	import java.util.function.Consumer;
29
30		/**
31		* An unbounded priority {@linkplain Queue queue} based on a priority heap.
#	Line 67 | Line 65 | import java.util.function.Block;
65		* java.util.concurrent.PriorityBlockingQueue} class.
66		*
67		* <p>Implementation note: this implementation provides
68	<	* O(log(n)) time for the enqueing and dequeing methods
68	>	* O(log(n)) time for the enqueuing and dequeuing methods
69		* ({@code offer}, {@code poll}, {@code remove()} and {@code add});
70		* linear time for the {@code remove(Object)} and {@code contains(Object)}
71		* methods; and constant time for the retrieval methods
#	Line 79 | Line 77 | import java.util.function.Block;
77		*
78		* @since 1.5
79		* @author Josh Bloch, Doug Lea
80	<	* @param <E> the type of elements held in this collection
80	>	* @param <E> the type of elements held in this queue
81		*/
82		public class PriorityQueue<E> extends AbstractQueue<E>
83		implements java.io.Serializable {
#	Line 101 | Line 99 | public class PriorityQueue<E> extends Ab
99		/**
100		* The number of elements in the priority queue.
101		*/
102	<	private int size = 0;
102	>	int size;
103
104		/**
105		* The comparator, or null if priority queue uses elements'
#	Line 113 | 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	<	transient int modCount = 0; // non-private to simplify nested class access
114	>	transient int modCount;     // non-private to simplify nested class access
115
116		/**
117		* Creates a {@code PriorityQueue} with the default initial
#	Line 138 | Line 136 | public class PriorityQueue<E> extends Ab
136		}
137
138		/**
139	+	* Creates a {@code PriorityQueue} with the default initial capacity and
140	+	* whose elements are ordered according to the specified comparator.
141	+	*
142	+	* @param  comparator the comparator that will be used to order this
143	+	*         priority queue.  If {@code null}, the {@linkplain Comparable
144	+	*         natural ordering} of the elements will be used.
145	+	* @since 1.8
146	+	*/
147	+	public PriorityQueue(Comparator<? super E> comparator) {
148	+	this(DEFAULT_INITIAL_CAPACITY, comparator);
149	+	}
150	+
151	+	/**
152		* Creates a {@code PriorityQueue} with the specified initial capacity
153		* that orders its elements according to the specified comparator.
154		*
#	Line 247 | Line 258 | public class PriorityQueue<E> extends Ab
258		a = Arrays.copyOf(a, a.length, Object[].class);
259		int len = a.length;
260		if (len == 1 || this.comparator != null)
261	<	for (int i = 0; i < len; i++)
262	<	if (a[i] == null)
261	>	for (Object e : a)
262	>	if (e == null)
263		throw new NullPointerException();
264		this.queue = a;
265		this.size = a.length;
#	Line 326 | Line 337 | public class PriorityQueue<E> extends Ab
337		int i = size;
338		if (i >= queue.length)
339		grow(i + 1);
340	+	siftUp(i, e);
341		size = i + 1;
330	–	if (i == 0)
331	–	queue[0] = e;
332	–	else
333	–	siftUp(i, e);
342		return true;
343		}
344
#	Line 395 | Line 403 | public class PriorityQueue<E> extends Ab
403		* @return {@code true} if this queue contains the specified element
404		*/
405		public boolean contains(Object o) {
406	<	return indexOf(o) != -1;
406	>	return indexOf(o) >= 0;
407		}
408
409		/**
#	Line 437 | Line 445 | public class PriorityQueue<E> extends Ab
445		* The following code can be used to dump the queue into a newly
446		* allocated array of {@code String}:
447		*
448	<	*  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
448	>	* <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
449		*
450		* Note that {@code toArray(new Object[0])} is identical in function to
451		* {@code toArray()}.
#	Line 478 | Line 486 | public class PriorityQueue<E> extends Ab
486		* Index (into queue array) of element to be returned by
487		* subsequent call to next.
488		*/
489	<	private int cursor = 0;
489	>	private int cursor;
490
491		/**
492		* Index of element returned by most recent call to next,
#	Line 498 | Line 506 | public class PriorityQueue<E> extends Ab
506		* We expect that most iterations, even those involving removals,
507		* will not need to store elements in this field.
508		*/
509	<	private ArrayDeque<E> forgetMeNot = null;
509	>	private ArrayDeque<E> forgetMeNot;
510
511		/**
512		* Element returned by the most recent call to next iff that
513		* element was drawn from the forgetMeNot list.
514		*/
515	<	private E lastRetElt = null;
515	>	private E lastRetElt;
516
517		/**
518		* The modCount value that the iterator believes that the backing
#	Line 543 | Line 551 | public class PriorityQueue<E> extends Ab
551		cursor--;
552		else {
553		if (forgetMeNot == null)
554	<	forgetMeNot = new ArrayDeque<E>();
554	>	forgetMeNot = new ArrayDeque<>();
555		forgetMeNot.add(moved);
556		}
557		} else if (lastRetElt != null) {
#	Line 598 | Line 606 | public class PriorityQueue<E> extends Ab
606		* avoid missing traversing elements.
607		*/
608		@SuppressWarnings("unchecked")
609	<	private E removeAt(int i) {
609	>	E removeAt(int i) {
610		// assert i >= 0 && i < size;
611		modCount++;
612		int s = --size;
#	Line 741 | Line 749 | public class PriorityQueue<E> extends Ab
749		/**
750		* Saves this queue to a stream (that is, serializes it).
751		*
752	+	* @param s the stream
753	+	* @throws java.io.IOException if an I/O error occurs
754		* @serialData The length of the array backing the instance is
755		*             emitted (int), followed by all of its elements
756		*             (each an {@code Object}) in the proper order.
747	–	* @param s the stream
757		*/
758		private void writeObject(java.io.ObjectOutputStream s)
759		throws java.io.IOException {
#	Line 764 | Line 773 | public class PriorityQueue<E> extends Ab
773		* (that is, deserializes it).
774		*
775		* @param s the stream
776	+	* @throws ClassNotFoundException if the class of a serialized object
777	+	*         could not be found
778	+	* @throws java.io.IOException if an I/O error occurs
779		*/
780		private void readObject(java.io.ObjectInputStream s)
781		throws java.io.IOException, ClassNotFoundException {
#	Line 784 | Line 796 | public class PriorityQueue<E> extends Ab
796		heapify();
797		}
798
799	<	// wrapping constructor in method avoids transient javac problems
800	<	final PriorityQueueSpliterator<E> spliterator(int origin, int fence,
801	<	int expectedModCount) {
802	<	return new PriorityQueueSpliterator<E>(this, origin, fence,
803	<	expectedModCount);
804	<	}
805	<
806	<	public Stream<E> stream() {
807	<	int flags = Streams.STREAM_IS_SIZED;
808	<	return Streams.stream
809	<	(() -> spliterator(0, size, modCount), flags);
810	<	}
811	<	public Stream<E> parallelStream() {
812	<	int flags = Streams.STREAM_IS_SIZED;
813	<	return Streams.parallelStream
802	<	(() -> spliterator(0, size, modCount), flags);
799	>	/**
800	>	* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em>
801	>	* and <em>fail-fast</em> {@link Spliterator} over the elements in this
802	>	* queue.
803	>	*
804	>	* <p>The {@code Spliterator} reports {@link Spliterator#SIZED},
805	>	* {@link Spliterator#SUBSIZED}, and {@link Spliterator#NONNULL}.
806	>	* Overriding implementations should document the reporting of additional
807	>	* characteristic values.
808	>	*
809	>	* @return a {@code Spliterator} over the elements in this queue
810	>	* @since 1.8
811	>	*/
812	>	public final Spliterator<E> spliterator() {
813	>	return new PriorityQueueSpliterator<>(this, 0, -1, 0);
814		}
815
805	–	/** Index-based split-by-two Spliterator */
816		static final class PriorityQueueSpliterator<E> implements Spliterator<E> {
817	+	/*
818	+	* This is very similar to ArrayList Spliterator, except for
819	+	* extra null checks.
820	+	*/
821		private final PriorityQueue<E> pq;
822	<	private int index;           // current index, modified on advance/split
823	<	private final int fence;     // one past last index
824	<	private final int expectedModCount; // for comodification checks
822	>	private int index;            // current index, modified on advance/split
823	>	private int fence;            // -1 until first use
824	>	private int expectedModCount; // initialized when fence set
825
826	<	/** Create new spliterator covering the given  range */
826	>	/** Creates new spliterator covering the given range. */
827		PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
828	<	int expectedModCount) {
829	<	this.pq = pq; this.index = origin; this.fence = fence;
828	>	int expectedModCount) {
829	>	this.pq = pq;
830	>	this.index = origin;
831	>	this.fence = fence;
832		this.expectedModCount = expectedModCount;
833		}
834
835	+	private int getFence() { // initialize fence to size on first use
836	+	int hi;
837	+	if ((hi = fence) < 0) {
838	+	expectedModCount = pq.modCount;
839	+	hi = fence = pq.size;
840	+	}
841	+	return hi;
842	+	}
843	+
844		public PriorityQueueSpliterator<E> trySplit() {
845	<	int lo = index, mid = (lo + fence) >>> 1;
845	>	int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
846		return (lo >= mid) ? null :
847	<	new PriorityQueueSpliterator<E>(pq, lo, index = mid,
848	<	expectedModCount);
847	>	new PriorityQueueSpliterator<>(pq, lo, index = mid,
848	>	expectedModCount);
849		}
850
851	<	public void forEach(Block<? super E> block) {
852	<	Object[] a; int i, hi; // hoist accesses and checks from loop
853	<	if (block == null)
851	>	@SuppressWarnings("unchecked")
852	>	public void forEachRemaining(Consumer<? super E> action) {
853	>	int i, hi, mc; // hoist accesses and checks from loop
854	>	PriorityQueue<E> q; Object[] a;
855	>	if (action == null)
856		throw new NullPointerException();
857	<	if ((a = pq.queue).length >= (hi = fence) &&
858	<	(i = index) >= 0 && i < hi) {
859	<	index = hi;
860	<	do {
861	<	@SuppressWarnings("unchecked") E e = (E) a[i];
862	<	block.accept(e);
863	<	} while (++i < hi);
864	<	if (pq.modCount != expectedModCount)
865	<	throw new ConcurrentModificationException();
857	>	if ((q = pq) != null && (a = q.queue) != null) {
858	>	if ((hi = fence) < 0) {
859	>	mc = q.modCount;
860	>	hi = q.size;
861	>	}
862	>	else
863	>	mc = expectedModCount;
864	>	if ((i = index) >= 0 && (index = hi) <= a.length) {
865	>	for (E e;; ++i) {
866	>	if (i < hi) {
867	>	if ((e = (E) a[i]) == null) // must be CME
868	>	break;
869	>	action.accept(e);
870	>	}
871	>	else if (q.modCount != mc)
872	>	break;
873	>	else
874	>	return;
875	>	}
876	>	}
877		}
878	+	throw new ConcurrentModificationException();
879		}
880
881	<	public boolean tryAdvance(Block<? super E> block) {
882	<	if (index >= 0 && index < fence) {
883	<	@SuppressWarnings("unchecked") E e =
884	<	(E)pq.queue[index++];
885	<	block.accept(e);
881	>	public boolean tryAdvance(Consumer<? super E> action) {
882	>	if (action == null)
883	>	throw new NullPointerException();
884	>	int hi = getFence(), lo = index;
885	>	if (lo >= 0 && lo < hi) {
886	>	index = lo + 1;
887	>	@SuppressWarnings("unchecked") E e = (E)pq.queue[lo];
888	>	if (e == null)
889	>	throw new ConcurrentModificationException();
890	>	action.accept(e);
891		if (pq.modCount != expectedModCount)
892		throw new ConcurrentModificationException();
893		return true;
#	Line 851 | Line 895 | public class PriorityQueue<E> extends Ab
895		return false;
896		}
897
898	<	public long estimateSize() { return (long)(fence - index); }
899	<	public boolean hasExactSize() { return true; }
900	<	public boolean hasExactSplits() { return true; }
898	>	public long estimateSize() {
899	>	return (long) (getFence() - index);
900	>	}
901	>
902	>	public int characteristics() {
903	>	return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL;
904	>	}
905		}
906		}

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