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Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.101 by jsr166, Tue Dec 2 05:48:28 2014 UTC vs.
Revision 1.123 by jsr166, Sun May 6 16:26:03 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 jdk.internal.misc.SharedSecrets;
30
31		/**
32		* An unbounded priority {@linkplain Queue queue} based on a priority heap.
#	Line 54 | Line 55 | import java.util.stream.Stream;
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 72 | Line 74 | import java.util.stream.Stream;
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
#	Line 99 | Line 101 | public class PriorityQueue<E> extends Ab
101		/**
102		* The number of elements in the priority queue.
103		*/
104	<	private int size;
104	>	int size;
105
106		/**
107		* The comparator, or null if priority queue uses elements'
#	Line 111 | 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 136 | 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 245 | 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 324 | 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;
328	–	if (i == 0)
329	–	queue[0] = e;
330	–	else
331	–	siftUp(i, e);
344		return true;
345		}
346
#	Line 339 | Line 351 | public class PriorityQueue<E> extends Ab
351
352		private int indexOf(Object o) {
353		if (o != null) {
354	<	for (int i = 0; i < size; i++)
355	<	if (o.equals(queue[i]))
354	>	final Object[] es = queue;
355	>	for (int i = 0, n = size; i < n; i++)
356	>	if (o.equals(es[i]))
357		return i;
358		}
359		return -1;
#	Line 368 | Line 381 | public class PriorityQueue<E> extends Ab
381		}
382
383		/**
384	<	* Version of remove using reference equality, not equals.
372	<	* Needed by iterator.remove.
384	>	* Identity-based version for use in Itr.remove.
385		*
386		* @param o element to be removed from this queue, if present
375	–	* @return {@code true} if removed
387		*/
388	<	boolean removeEq(Object o) {
389	<	for (int i = 0; i < size; i++) {
390	<	if (o == queue[i]) {
388	>	void removeEq(Object o) {
389	>	final Object[] es = queue;
390	>	for (int i = 0, n = size; i < n; i++) {
391	>	if (o == es[i]) {
392		removeAt(i);
393	<	return true;
393	>	break;
394		}
395		}
384	–	return false;
396		}
397
398		/**
#	Line 435 | Line 446 | public class PriorityQueue<E> extends Ab
446		* The following code can be used to dump the queue into a newly
447		* allocated array of {@code String}:
448		*
449	<	*  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
449	>	* <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
450		*
451		* Note that {@code toArray(new Object[0])} is identical in function to
452		* {@code toArray()}.
#	Line 511 | Line 522 | public class PriorityQueue<E> extends Ab
522		*/
523		private int expectedModCount = modCount;
524
525	+	Itr() {}                        // prevent access constructor creation
526	+
527		public boolean hasNext() {
528		return cursor < size ||
529		(forgetMeNot != null && !forgetMeNot.isEmpty());
#	Line 564 | Line 577 | public class PriorityQueue<E> extends Ab
577		*/
578		public void clear() {
579		modCount++;
580	<	for (int i = 0; i < size; i++)
581	<	queue[i] = null;
580	>	final Object[] es = queue;
581	>	for (int i = 0, n = size; i < n; i++)
582	>	es[i] = null;
583		size = 0;
584		}
585
#	Line 596 | 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 620 | 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 716 | 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 739 | 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.
745	–	* @param s the stream
746	–	* @throws java.io.IOException if an I/O error occurs
768		*/
769		private void writeObject(java.io.ObjectOutputStream s)
770		throws java.io.IOException {
#	Line 754 | Line 775 | public class PriorityQueue<E> extends Ab
775		s.writeInt(Math.max(2, size + 1));
776
777		// Write out all elements in the "proper order".
778	<	for (int i = 0; i < size; i++)
779	<	s.writeObject(queue[i]);
778	>	final Object[] es = queue;
779	>	for (int i = 0, n = size; i < n; i++)
780	>	s.writeObject(es[i]);
781		}
782
783		/**
#	Line 775 | Line 797 | public class PriorityQueue<E> extends Ab
797		// Read in (and discard) array length
798		s.readInt();
799
800	+	SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Object[].class, size);
801		queue = new Object[size];
802
803		// Read in all elements.
804	<	for (int i = 0; i < size; i++)
805	<	queue[i] = s.readObject();
804	>	final Object[] es = queue;
805	>	for (int i = 0, n = size; i < n; i++)
806	>	es[i] = s.readObject();
807
808		// Elements are guaranteed to be in "proper order", but the
809		// spec has never explained what that might be.
810		heapify();
811		}
812
789	–	public Spliterator<E> spliterator() {
790	–	return new PriorityQueueSpliterator<E>(this, 0, -1, 0);
791	–	}
792	–
813		/**
814	<	* This is very similar to ArrayList Spliterator, except for extra
815	<	* null checks.
814	>	* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em>
815	>	* and <em>fail-fast</em> {@link Spliterator} over the elements in this
816	>	* queue. The spliterator does not traverse elements in any particular order
817	>	* (the {@link Spliterator#ORDERED ORDERED} characteristic is not reported).
818	>	*
819	>	* <p>The {@code Spliterator} reports {@link Spliterator#SIZED},
820	>	* {@link Spliterator#SUBSIZED}, and {@link Spliterator#NONNULL}.
821	>	* Overriding implementations should document the reporting of additional
822	>	* characteristic values.
823	>	*
824	>	* @return a {@code Spliterator} over the elements in this queue
825	>	* @since 1.8
826		*/
827	<	static final class PriorityQueueSpliterator<E> implements Spliterator<E> {
828	<	private final PriorityQueue<E> pq;
827	>	public final Spliterator<E> spliterator() {
828	>	return new PriorityQueueSpliterator(0, -1, 0);
829	>	}
830	>
831	>	final class PriorityQueueSpliterator implements Spliterator<E> {
832		private int index;            // current index, modified on advance/split
833		private int fence;            // -1 until first use
834		private int expectedModCount; // initialized when fence set
835
836	<	/** Creates new spliterator covering the given range */
837	<	PriorityQueueSpliterator(PriorityQueue<E> pq, int origin, int fence,
805	<	int expectedModCount) {
806	<	this.pq = pq;
836	>	/** Creates new spliterator covering the given range. */
837	>	PriorityQueueSpliterator(int origin, int fence, int expectedModCount) {
838		this.index = origin;
839		this.fence = fence;
840		this.expectedModCount = expectedModCount;
#	Line 812 | Line 843 | public class PriorityQueue<E> extends Ab
843		private int getFence() { // initialize fence to size on first use
844		int hi;
845		if ((hi = fence) < 0) {
846	<	expectedModCount = pq.modCount;
847	<	hi = fence = pq.size;
846	>	expectedModCount = modCount;
847	>	hi = fence = size;
848		}
849		return hi;
850		}
851
852	<	public Spliterator<E> trySplit() {
852	>	public PriorityQueueSpliterator trySplit() {
853		int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
854		return (lo >= mid) ? null :
855	<	new PriorityQueueSpliterator<E>(pq, lo, index = mid,
825	<	expectedModCount);
855	>	new PriorityQueueSpliterator(lo, index = mid, expectedModCount);
856		}
857
858		@SuppressWarnings("unchecked")
859		public void forEachRemaining(Consumer<? super E> action) {
830	–	int i, hi, mc; // hoist accesses and checks from loop
831	–	PriorityQueue<E> q; Object[] a;
860		if (action == null)
861		throw new NullPointerException();
862	<	if ((q = pq) != null && (a = q.queue) != null) {
863	<	if ((hi = fence) < 0) {
864	<	mc = q.modCount;
865	<	hi = q.size;
866	<	}
867	<	else
868	<	mc = expectedModCount;
841	<	if ((i = index) >= 0 && (index = hi) <= a.length) {
842	<	for (E e;; ++i) {
843	<	if (i < hi) {
844	<	if ((e = (E) a[i]) == null) // must be CME
845	<	break;
846	<	action.accept(e);
847	<	}
848	<	else if (q.modCount != mc)
849	<	break;
850	<	else
851	<	return;
852	<	}
853	<	}
862	>	if (fence < 0) { fence = size; expectedModCount = modCount; }
863	>	final Object[] a = queue;
864	>	int i, hi; E e;
865	>	for (i = index, index = hi = fence; i < hi; i++) {
866	>	if ((e = (E) a[i]) == null)
867	>	break;      // must be CME
868	>	action.accept(e);
869		}
870	<	throw new ConcurrentModificationException();
870	>	if (modCount != expectedModCount)
871	>	throw new ConcurrentModificationException();
872		}
873
874	+	@SuppressWarnings("unchecked")
875		public boolean tryAdvance(Consumer<? super E> action) {
876	<	int hi = getFence(), lo = index;
877	<	if (lo >= 0 && lo < hi) {
878	<	index = lo + 1;
879	<	@SuppressWarnings("unchecked") E e = (E)pq.queue[lo];
880	<	if (e == null)
876	>	if (action == null)
877	>	throw new NullPointerException();
878	>	if (fence < 0) { fence = size; expectedModCount = modCount; }
879	>	int i;
880	>	if ((i = index) < fence) {
881	>	index = i + 1;
882	>	E e;
883	>	if ((e = (E) queue[i]) == null
884	>	|| modCount != expectedModCount)
885		throw new ConcurrentModificationException();
886		action.accept(e);
866	–	if (pq.modCount != expectedModCount)
867	–	throw new ConcurrentModificationException();
887		return true;
888		}
889		return false;
890		}
891
892		public long estimateSize() {
893	<	return (long) (getFence() - index);
893	>	return getFence() - index;
894		}
895
896		public int characteristics() {
897		return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL;
898		}
899		}
900	+
901	+	/**
902	+	* @throws NullPointerException {@inheritDoc}
903	+	*/
904	+	@SuppressWarnings("unchecked")
905	+	public void forEach(Consumer<? super E> action) {
906	+	Objects.requireNonNull(action);
907	+	final int expectedModCount = modCount;
908	+	final Object[] es = queue;
909	+	for (int i = 0, n = size; i < n; i++)
910	+	action.accept((E) es[i]);
911	+	if (expectedModCount != modCount)
912	+	throw new ConcurrentModificationException();
913	+	}
914		}

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