--- jsr166/src/main/java/util/PriorityQueue.java 2016/06/01 16:08:04 1.109
+++ jsr166/src/main/java/util/PriorityQueue.java 2018/05/06 02:08:36 1.122
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2018, 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
@@ -26,6 +26,7 @@
package java.util;
import java.util.function.Consumer;
+import jdk.internal.misc.SharedSecrets;
/**
* An unbounded priority {@linkplain Queue queue} based on a priority heap.
@@ -54,7 +55,8 @@ import java.util.function.Consumer;
*
This class and its iterator implement all of the
* optional methods of the {@link Collection} and {@link
* Iterator} interfaces. The Iterator provided in method {@link
- * #iterator()} is not guaranteed to traverse the elements of
+ * #iterator()} and the Spliterator provided in method {@link #spliterator()}
+ * are not guaranteed to traverse the elements of
* the priority queue in any particular order. If you need ordered
* traversal, consider using {@code Arrays.sort(pq.toArray())}.
*
@@ -72,7 +74,7 @@ import java.util.function.Consumer;
* ({@code peek}, {@code element}, and {@code size}).
*
*
This class is a member of the
- *
+ *
* Java Collections Framework.
*
* @since 1.5
@@ -521,6 +523,8 @@ public class PriorityQueue extends Ab
*/
private int expectedModCount = modCount;
+ Itr() {} // prevent access constructor creation
+
public boolean hasNext() {
return cursor < size ||
(forgetMeNot != null && !forgetMeNot.isEmpty());
@@ -630,7 +634,7 @@ public class PriorityQueue extends Ab
* promoting x up the tree until it is greater than or equal to
* its parent, or is the root.
*
- * To simplify and speed up coercions and comparisons. the
+ * To simplify and speed up coercions and comparisons, the
* Comparable and Comparator versions are separated into different
* methods that are otherwise identical. (Similarly for siftDown.)
*
@@ -726,11 +730,18 @@ public class PriorityQueue extends Ab
/**
* Establishes the heap invariant (described above) in the entire tree,
* assuming nothing about the order of the elements prior to the call.
+ * This classic algorithm due to Floyd (1964) is known to be O(size).
*/
@SuppressWarnings("unchecked")
private void heapify() {
- for (int i = (size >>> 1) - 1; i >= 0; i--)
- siftDown(i, (E) queue[i]);
+ final Object[] es = queue;
+ int i = (size >>> 1) - 1;
+ if (comparator == null)
+ for (; i >= 0; i--)
+ siftDownComparable(i, (E) es[i]);
+ else
+ for (; i >= 0; i--)
+ siftDownUsingComparator(i, (E) es[i]);
}
/**
@@ -749,11 +760,11 @@ public class PriorityQueue extends Ab
/**
* Saves this queue to a stream (that is, serializes it).
*
+ * @param s the stream
+ * @throws java.io.IOException if an I/O error occurs
* @serialData The length of the array backing the instance is
* emitted (int), followed by all of its elements
* (each an {@code Object}) in the proper order.
- * @param s the stream
- * @throws java.io.IOException if an I/O error occurs
*/
private void writeObject(java.io.ObjectOutputStream s)
throws java.io.IOException {
@@ -785,6 +796,7 @@ public class PriorityQueue extends Ab
// Read in (and discard) array length
s.readInt();
+ SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Object[].class, size);
queue = new Object[size];
// Read in all elements.
@@ -799,7 +811,8 @@ public class PriorityQueue extends Ab
/**
* Creates a late-binding
* and fail-fast {@link Spliterator} over the elements in this
- * queue.
+ * queue. The spliterator does not traverse elements in any particular order
+ * (the {@link Spliterator#ORDERED ORDERED} characteristic is not reported).
*
* The {@code Spliterator} reports {@link Spliterator#SIZED},
* {@link Spliterator#SUBSIZED}, and {@link Spliterator#NONNULL}.
@@ -810,23 +823,16 @@ public class PriorityQueue extends Ab
* @since 1.8
*/
public final Spliterator spliterator() {
- return new PriorityQueueSpliterator<>(this, 0, -1, 0);
+ return new PriorityQueueSpliterator(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;
+ final class PriorityQueueSpliterator implements Spliterator {
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. */
- PriorityQueueSpliterator(PriorityQueue pq, int origin, int fence,
- int expectedModCount) {
- this.pq = pq;
+ PriorityQueueSpliterator(int origin, int fence, int expectedModCount) {
this.index = origin;
this.fence = fence;
this.expectedModCount = expectedModCount;
@@ -835,72 +841,72 @@ public class PriorityQueue extends Ab
private int getFence() { // initialize fence to size on first use
int hi;
if ((hi = fence) < 0) {
- expectedModCount = pq.modCount;
- hi = fence = pq.size;
+ expectedModCount = modCount;
+ hi = fence = size;
}
return hi;
}
- public PriorityQueueSpliterator 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(lo, index = mid, expectedModCount);
}
@SuppressWarnings("unchecked")
public void forEachRemaining(Consumer super E> action) {
- int i, hi, mc; // hoist accesses and checks from loop
- PriorityQueue q; Object[] a;
if (action == null)
throw new NullPointerException();
- if ((q = pq) != null && (a = q.queue) != null) {
- if ((hi = fence) < 0) {
- mc = q.modCount;
- hi = q.size;
- }
- else
- mc = expectedModCount;
- if ((i = index) >= 0 && (index = hi) <= a.length) {
- for (E e;; ++i) {
- if (i < hi) {
- if ((e = (E) a[i]) == null) // must be CME
- break;
- action.accept(e);
- }
- else if (q.modCount != mc)
- break;
- else
- return;
- }
- }
+ if (fence < 0) { fence = size; expectedModCount = modCount; }
+ final Object[] a = queue;
+ int i, hi; E e;
+ for (i = index, index = hi = fence; i < hi; i++) {
+ if ((e = (E) a[i]) == null)
+ break; // must be CME
+ action.accept(e);
}
- throw new ConcurrentModificationException();
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
}
+ @SuppressWarnings("unchecked")
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;
- @SuppressWarnings("unchecked") E e = (E)pq.queue[lo];
- if (e == null)
+ if (fence < 0) { fence = size; expectedModCount = modCount; }
+ int i;
+ if ((i = index) < fence) {
+ index = i + 1;
+ E e;
+ if ((e = (E) queue[i]) == null
+ || modCount != expectedModCount)
throw new ConcurrentModificationException();
action.accept(e);
- if (pq.modCount != expectedModCount)
- throw new ConcurrentModificationException();
return true;
}
return false;
}
public long estimateSize() {
- return (long) (getFence() - index);
+ return getFence() - index;
}
public int characteristics() {
return Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.NONNULL;
}
}
+
+ /**
+ * @throws NullPointerException {@inheritDoc}
+ */
+ @SuppressWarnings("unchecked")
+ public void forEach(Consumer super E> action) {
+ Objects.requireNonNull(action);
+ final int expectedModCount = modCount;
+ final Object[] es = queue;
+ for (int i = 0, n = size; i < n; i++)
+ action.accept((E) es[i]);
+ if (expectedModCount != modCount)
+ throw new ConcurrentModificationException();
+ }
}