--- jsr166/src/main/java/util/PriorityQueue.java 2013/07/18 18:21:22 1.97
+++ jsr166/src/main/java/util/PriorityQueue.java 2016/06/01 16:08:04 1.109
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -24,8 +24,8 @@
*/
package java.util;
+
import java.util.function.Consumer;
-import java.util.stream.Stream;
/**
* An unbounded priority {@linkplain Queue queue} based on a priority heap.
@@ -65,7 +65,7 @@ import java.util.stream.Stream;
* java.util.concurrent.PriorityBlockingQueue} class.
*
*
Implementation note: this implementation provides
- * O(log(n)) time for the enqueing and dequeing methods
+ * O(log(n)) time for the enqueuing and dequeuing methods
* ({@code offer}, {@code poll}, {@code remove()} and {@code add});
* linear time for the {@code remove(Object)} and {@code contains(Object)}
* methods; and constant time for the retrieval methods
@@ -77,7 +77,7 @@ import java.util.stream.Stream;
*
* @since 1.5
* @author Josh Bloch, Doug Lea
- * @param the type of elements held in this collection
+ * @param the type of elements held in this queue
*/
public class PriorityQueue extends AbstractQueue
implements java.io.Serializable {
@@ -99,7 +99,7 @@ public class PriorityQueue extends Ab
/**
* The number of elements in the priority queue.
*/
- private int size = 0;
+ int size;
/**
* The comparator, or null if priority queue uses elements'
@@ -111,7 +111,7 @@ public class PriorityQueue extends Ab
* The number of times this priority queue has been
* structurally modified. See AbstractList for gory details.
*/
- transient int modCount = 0; // non-private to simplify nested class access
+ transient int modCount; // non-private to simplify nested class access
/**
* Creates a {@code PriorityQueue} with the default initial
@@ -136,6 +136,19 @@ public class PriorityQueue extends Ab
}
/**
+ * Creates a {@code PriorityQueue} with the default initial capacity and
+ * whose elements are ordered according to the specified comparator.
+ *
+ * @param comparator the comparator that will be used to order this
+ * priority queue. If {@code null}, the {@linkplain Comparable
+ * natural ordering} of the elements will be used.
+ * @since 1.8
+ */
+ public PriorityQueue(Comparator super E> comparator) {
+ this(DEFAULT_INITIAL_CAPACITY, comparator);
+ }
+
+ /**
* Creates a {@code PriorityQueue} with the specified initial capacity
* that orders its elements according to the specified comparator.
*
@@ -245,8 +258,8 @@ public class PriorityQueue extends Ab
a = Arrays.copyOf(a, a.length, Object[].class);
int len = a.length;
if (len == 1 || this.comparator != null)
- for (int i = 0; i < len; i++)
- if (a[i] == null)
+ for (Object e : a)
+ if (e == null)
throw new NullPointerException();
this.queue = a;
this.size = a.length;
@@ -324,11 +337,8 @@ public class PriorityQueue extends Ab
int i = size;
if (i >= queue.length)
grow(i + 1);
+ siftUp(i, e);
size = i + 1;
- if (i == 0)
- queue[0] = e;
- else
- siftUp(i, e);
return true;
}
@@ -393,7 +403,7 @@ public class PriorityQueue extends Ab
* @return {@code true} if this queue contains the specified element
*/
public boolean contains(Object o) {
- return indexOf(o) != -1;
+ return indexOf(o) >= 0;
}
/**
@@ -435,7 +445,7 @@ public class PriorityQueue extends Ab
* The following code can be used to dump the queue into a newly
* allocated array of {@code String}:
*
- * {@code String[] y = x.toArray(new String[0]);}
+ * {@code String[] y = x.toArray(new String[0]);}
*
* Note that {@code toArray(new Object[0])} is identical in function to
* {@code toArray()}.
@@ -476,7 +486,7 @@ public class PriorityQueue extends Ab
* Index (into queue array) of element to be returned by
* subsequent call to next.
*/
- private int cursor = 0;
+ private int cursor;
/**
* Index of element returned by most recent call to next,
@@ -496,13 +506,13 @@ public class PriorityQueue extends Ab
* We expect that most iterations, even those involving removals,
* will not need to store elements in this field.
*/
- private ArrayDeque forgetMeNot = null;
+ private ArrayDeque forgetMeNot;
/**
* Element returned by the most recent call to next iff that
* element was drawn from the forgetMeNot list.
*/
- private E lastRetElt = null;
+ private E lastRetElt;
/**
* The modCount value that the iterator believes that the backing
@@ -596,7 +606,7 @@ public class PriorityQueue extends Ab
* avoid missing traversing elements.
*/
@SuppressWarnings("unchecked")
- private E removeAt(int i) {
+ E removeAt(int i) {
// assert i >= 0 && i < size;
modCount++;
int s = --size;
@@ -786,23 +796,36 @@ public class PriorityQueue extends Ab
heapify();
}
- public Spliterator spliterator() {
- return new PriorityQueueSpliterator(this, 0, -1, 0);
- }
-
/**
- * This is very similar to ArrayList Spliterator, except for extra
- * null checks.
+ * Creates a late-binding
+ * and fail-fast {@link Spliterator} over the elements in this
+ * queue.
+ *
+ * The {@code Spliterator} reports {@link Spliterator#SIZED},
+ * {@link Spliterator#SUBSIZED}, and {@link Spliterator#NONNULL}.
+ * Overriding implementations should document the reporting of additional
+ * characteristic values.
+ *
+ * @return a {@code Spliterator} over the elements in this queue
+ * @since 1.8
*/
+ public final Spliterator spliterator() {
+ return new PriorityQueueSpliterator<>(this, 0, -1, 0);
+ }
+
static final class PriorityQueueSpliterator implements Spliterator {
+ /*
+ * This is very similar to ArrayList Spliterator, except for
+ * extra null checks.
+ */
private final PriorityQueue pq;
private int index; // current index, modified on advance/split
private int fence; // -1 until first use
private int expectedModCount; // initialized when fence set
- /** Creates new spliterator covering the given range */
+ /** Creates new spliterator covering the given range. */
PriorityQueueSpliterator(PriorityQueue pq, int origin, int fence,
- int expectedModCount) {
+ int expectedModCount) {
this.pq = pq;
this.index = origin;
this.fence = fence;
@@ -818,11 +841,11 @@ public class PriorityQueue extends Ab
return hi;
}
- public Spliterator trySplit() {
+ public PriorityQueueSpliterator trySplit() {
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
return (lo >= mid) ? null :
- new PriorityQueueSpliterator(pq, lo, index = mid,
- expectedModCount);
+ new PriorityQueueSpliterator<>(pq, lo, index = mid,
+ expectedModCount);
}
@SuppressWarnings("unchecked")
@@ -856,6 +879,8 @@ public class PriorityQueue extends Ab
}
public boolean tryAdvance(Consumer super E> action) {
+ if (action == null)
+ throw new NullPointerException();
int hi = getFence(), lo = index;
if (lo >= 0 && lo < hi) {
index = lo + 1;