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Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.90 by jsr166, Mon Feb 18 01:30:23 2013 UTC vs.
Revision 1.121 by jsr166, Wed Mar 28 02:50:41 2018 UTC

#	Line 1 | Line 1
1		/*
2	<	* Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
2	>	* Copyright (c) 2003, 2018, 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	+
28		import java.util.function.Consumer;
29	<	import java.util.stream.Stream;
29	<	import java.util.stream.Streams;
29	>	import jdk.internal.misc.SharedSecrets;
30
31		/**
32		* An unbounded priority {@linkplain Queue queue} based on a priority heap.
#	Line 55 | Line 55 | import java.util.stream.Streams;
55		* <p>This class and its iterator implement all of the
56		* <em>optional</em> methods of the {@link Collection} and {@link
57		* Iterator} interfaces.  The Iterator provided in method {@link
58	<	* #iterator()} is <em>not</em> guaranteed to traverse the elements of
58	>	* #iterator()} and the Spliterator provided in method {@link #spliterator()}
59	>	* are <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 {@code Arrays.sort(pq.toArray())}.
62		*
#	Line 66 | Line 67 | import java.util.stream.Streams;
67		* java.util.concurrent.PriorityBlockingQueue} class.
68		*
69		* <p>Implementation note: this implementation provides
70	<	* O(log(n)) time for the enqueing and dequeing methods
70	>	* O(log(n)) time for the enqueuing and dequeuing 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}/../technotes/guides/collections/index.html">
77	>	* <a href="{@docRoot}/java/util/package-summary.html#CollectionsFramework">
78		* Java Collections Framework</a>.
79		*
80		* @since 1.5
81		* @author Josh Bloch, Doug Lea
82	<	* @param <E> the type of elements held in this collection
82	>	* @param <E> the type of elements held in this queue
83		*/
84		public class PriorityQueue<E> extends AbstractQueue<E>
85		implements java.io.Serializable {
#	Line 100 | Line 101 | public class PriorityQueue<E> extends Ab
101		/**
102		* The number of elements in the priority queue.
103		*/
104	<	private int size = 0;
104	>	int size;
105
106		/**
107		* The comparator, or null if priority queue uses elements'
#	Line 112 | 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	<	transient int modCount = 0; // non-private to simplify nested class access
116	>	transient int modCount;     // non-private to simplify nested class access
117
118		/**
119		* Creates a {@code PriorityQueue} with the default initial
#	Line 137 | Line 138 | public class PriorityQueue<E> extends Ab
138		}
139
140		/**
141	+	* Creates a {@code PriorityQueue} with the default initial capacity and
142	+	* whose elements are ordered according to the specified comparator.
143	+	*
144	+	* @param  comparator the comparator that will be used to order this
145	+	*         priority queue.  If {@code null}, the {@linkplain Comparable
146	+	*         natural ordering} of the elements will be used.
147	+	* @since 1.8
148	+	*/
149	+	public PriorityQueue(Comparator<? super E> comparator) {
150	+	this(DEFAULT_INITIAL_CAPACITY, comparator);
151	+	}
152	+
153	+	/**
154		* Creates a {@code PriorityQueue} with the specified initial capacity
155		* that orders its elements according to the specified comparator.
156		*
#	Line 246 | Line 260 | public class PriorityQueue<E> extends Ab
260		a = Arrays.copyOf(a, a.length, Object[].class);
261		int len = a.length;
262		if (len == 1 || this.comparator != null)
263	<	for (int i = 0; i < len; i++)
264	<	if (a[i] == null)
263	>	for (Object e : a)
264	>	if (e == null)
265		throw new NullPointerException();
266		this.queue = a;
267		this.size = a.length;
#	Line 325 | Line 339 | public class PriorityQueue<E> extends Ab
339		int i = size;
340		if (i >= queue.length)
341		grow(i + 1);
342	+	siftUp(i, e);
343		size = i + 1;
329	–	if (i == 0)
330	–	queue[0] = e;
331	–	else
332	–	siftUp(i, e);
344		return true;
345		}
346
#	Line 394 | Line 405 | public class PriorityQueue<E> extends Ab
405		* @return {@code true} if this queue contains the specified element
406		*/
407		public boolean contains(Object o) {
408	<	return indexOf(o) != -1;
408	>	return indexOf(o) >= 0;
409		}
410
411		/**
#	Line 436 | Line 447 | public class PriorityQueue<E> extends Ab
447		* The following code can be used to dump the queue into a newly
448		* allocated array of {@code String}:
449		*
450	<	*  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
450	>	* <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
451		*
452		* Note that {@code toArray(new Object[0])} is identical in function to
453		* {@code toArray()}.
#	Line 477 | Line 488 | public class PriorityQueue<E> extends Ab
488		* Index (into queue array) of element to be returned by
489		* subsequent call to next.
490		*/
491	<	private int cursor = 0;
491	>	private int cursor;
492
493		/**
494		* Index of element returned by most recent call to next,
#	Line 497 | Line 508 | public class PriorityQueue<E> extends Ab
508		* We expect that most iterations, even those involving removals,
509		* will not need to store elements in this field.
510		*/
511	<	private ArrayDeque<E> forgetMeNot = null;
511	>	private ArrayDeque<E> forgetMeNot;
512
513		/**
514		* Element returned by the most recent call to next iff that
515		* element was drawn from the forgetMeNot list.
516		*/
517	<	private E lastRetElt = null;
517	>	private E lastRetElt;
518
519		/**
520		* The modCount value that the iterator believes that the backing
#	Line 512 | Line 523 | public class PriorityQueue<E> extends Ab
523		*/
524		private int expectedModCount = modCount;
525
526	+	Itr() {}                        // prevent access constructor creation
527	+
528		public boolean hasNext() {
529		return cursor < size ||
530		(forgetMeNot != null && !forgetMeNot.isEmpty());
#	Line 597 | Line 610 | public class PriorityQueue<E> extends Ab
610		* avoid missing traversing elements.
611		*/
612		@SuppressWarnings("unchecked")
613	<	private E removeAt(int i) {
613	>	E removeAt(int i) {
614		// assert i >= 0 && i < size;
615		modCount++;
616		int s = --size;
#	Line 621 | Line 634 | public class PriorityQueue<E> extends Ab
634		* promoting x up the tree until it is greater than or equal to
635		* its parent, or is the root.
636		*
637	<	* To simplify and speed up coercions and comparisons. the
637	>	* To simplify and speed up coercions and comparisons, the
638		* Comparable and Comparator versions are separated into different
639		* methods that are otherwise identical. (Similarly for siftDown.)
640		*
#	Line 717 | Line 730 | public class PriorityQueue<E> extends Ab
730		/**
731		* Establishes the heap invariant (described above) in the entire tree,
732		* assuming nothing about the order of the elements prior to the call.
733	+	* This classic algorithm due to Floyd (1964) is known to be O(size).
734		*/
735		@SuppressWarnings("unchecked")
736		private void heapify() {
737	<	for (int i = (size >>> 1) - 1; i >= 0; i--)
738	<	siftDown(i, (E) queue[i]);
737	>	final Object[] es = queue;
738	>	int i = (size >>> 1) - 1;
739	>	if (comparator == null)
740	>	for (; i >= 0; i--)
741	>	siftDownComparable(i, (E) es[i]);
742	>	else
743	>	for (; i >= 0; i--)
744	>	siftDownUsingComparator(i, (E) es[i]);
745		}
746
747		/**
#	Line 740 | Line 760 | public class PriorityQueue<E> extends Ab
760		/**
761		* Saves this queue to a stream (that is, serializes it).
762		*
763	+	* @param s the stream
764	+	* @throws java.io.IOException if an I/O error occurs
765		* @serialData The length of the array backing the instance is
766		*             emitted (int), followed by all of its elements
767		*             (each an {@code Object}) in the proper order.
746	–	* @param s the stream
768		*/
769		private void writeObject(java.io.ObjectOutputStream s)
770		throws java.io.IOException {
#	Line 763 | Line 784 | public class PriorityQueue<E> extends Ab
784		* (that is, deserializes it).
785		*
786		* @param s the stream
787	+	* @throws ClassNotFoundException if the class of a serialized object
788	+	*         could not be found
789	+	* @throws java.io.IOException if an I/O error occurs
790		*/
791		private void readObject(java.io.ObjectInputStream s)
792		throws java.io.IOException, ClassNotFoundException {
#	Line 772 | Line 796 | public class PriorityQueue<E> extends Ab
796		// Read in (and discard) array length
797		s.readInt();
798
799	+	SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Object[].class, size);
800		queue = new Object[size];
801
802		// Read in all elements.
#	Line 783 | Line 808 | public class PriorityQueue<E> extends Ab
808		heapify();
809		}
810
811	<	final Spliterator<E> spliterator() {
812	<	return new PriorityQueueSpliterator<E>(this, 0, -1, 0);
813	<	}
814	<
815	<	public Stream<E> stream() {
816	<	return Streams.stream(spliterator());
817	<	}
818	<
819	<	public Stream<E> parallelStream() {
820	<	return Streams.parallelStream(spliterator());
811	>	/**
812	>	* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em>
813	>	* and <em>fail-fast</em> {@link Spliterator} over the elements in this
814	>	* queue. The spliterator does not traverse elements in any particular order
815	>	* (the {@link Spliterator#ORDERED ORDERED} characteristic is not reported).
816	>	*
817	>	* <p>The {@code Spliterator} reports {@link Spliterator#SIZED},
818	>	* {@link Spliterator#SUBSIZED}, and {@link Spliterator#NONNULL}.
819	>	* Overriding implementations should document the reporting of additional
820	>	* characteristic values.
821	>	*
822	>	* @return a {@code Spliterator} over the elements in this queue
823	>	* @since 1.8
824	>	*/
825	>	public final Spliterator<E> spliterator() {
826	>	return new PriorityQueueSpliterator(0, -1, 0);
827		}
828
829	<	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;
829	>	final class PriorityQueueSpliterator implements Spliterator<E> {
830		private int index;            // current index, modified on advance/split
831		private int fence;            // -1 until first use
832		private int expectedModCount; // initialized when fence set
833
834	<	/** Create new spliterator covering the given  range */
835	<	PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
810	<	int expectedModCount) {
811	<	this.pq = pq;
834	>	/** Creates new spliterator covering the given range. */
835	>	PriorityQueueSpliterator(int origin, int fence, int expectedModCount) {
836		this.index = origin;
837		this.fence = fence;
838		this.expectedModCount = expectedModCount;
#	Line 817 | Line 841 | public class PriorityQueue<E> extends Ab
841		private int getFence() { // initialize fence to size on first use
842		int hi;
843		if ((hi = fence) < 0) {
844	<	expectedModCount = pq.modCount;
845	<	hi = fence = pq.size;
844	>	expectedModCount = modCount;
845	>	hi = fence = size;
846		}
847		return hi;
848		}
849
850	<	public PriorityQueueSpliterator<E> trySplit() {
850	>	public PriorityQueueSpliterator trySplit() {
851		int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
852		return (lo >= mid) ? null :
853	<	new PriorityQueueSpliterator<E>(pq, lo, index = mid,
830	<	expectedModCount);
853	>	new PriorityQueueSpliterator(lo, index = mid, expectedModCount);
854		}
855
856		@SuppressWarnings("unchecked")
857	<	public void forEach(Consumer<? super E> action) {
835	<	int i, hi, mc; // hoist accesses and checks from loop
836	<	PriorityQueue<E> q; Object[] a;
857	>	public void forEachRemaining(Consumer<? super E> action) {
858		if (action == null)
859		throw new NullPointerException();
860	<	if ((q = pq) != null && (a = q.queue) != null) {
861	<	if ((hi = fence) < 0) {
862	<	mc = q.modCount;
863	<	hi = q.size;
864	<	}
865	<	else
866	<	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	<	}
860	>	if (fence < 0) { fence = size; expectedModCount = modCount; }
861	>	final Object[] a = queue;
862	>	int i, hi; E e;
863	>	for (i = index, index = hi = fence; i < hi; i++) {
864	>	if ((e = (E) a[i]) == null)
865	>	break;      // must be CME
866	>	action.accept(e);
867		}
868	<	throw new ConcurrentModificationException();
868	>	if (modCount != expectedModCount)
869	>	throw new ConcurrentModificationException();
870		}
871
872	+	@SuppressWarnings("unchecked")
873		public boolean tryAdvance(Consumer<? super E> action) {
874	<	int hi = getFence(), lo = index;
875	<	if (lo >= 0 && lo < hi) {
876	<	index = lo + 1;
877	<	@SuppressWarnings("unchecked") E e = (E)pq.queue[lo];
878	<	if (e == null)
874	>	if (action == null)
875	>	throw new NullPointerException();
876	>	if (fence < 0) { fence = size; expectedModCount = modCount; }
877	>	int i;
878	>	if ((i = index) < fence) {
879	>	index = i + 1;
880	>	E e;
881	>	if ((e = (E) queue[i]) == null
882	>	|| modCount != expectedModCount)
883		throw new ConcurrentModificationException();
884		action.accept(e);
871	–	if (pq.modCount != expectedModCount)
872	–	throw new ConcurrentModificationException();
885		return true;
886		}
887		return false;
888		}
889
890		public long estimateSize() {
891	<	return (long) (getFence() - index);
891	>	return getFence() - index;
892		}
893
894		public int characteristics() {

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