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/* |
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* Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved. |
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* Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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package java.util; |
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import java.util.function.Consumer; |
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import jdk.internal.misc.SharedSecrets; |
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import java.util.function.Predicate; |
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// OPENJDK import jdk.internal.access.SharedSecrets; |
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import jdk.internal.util.ArraysSupport; |
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/** |
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* An unbounded priority {@linkplain Queue queue} based on a priority heap. |
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* ({@code peek}, {@code element}, and {@code size}). |
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* |
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* <p>This class is a member of the |
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* <a href="{@docRoot}/java/util/package-summary.html#CollectionsFramework"> |
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* <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework"> |
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* Java Collections Framework</a>. |
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* |
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* @since 1.5 |
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initElementsFromCollection(c); |
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} |
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/** Ensures that queue[0] exists, helping peek() and poll(). */ |
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private static Object[] ensureNonEmpty(Object[] es) { |
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return (es.length > 0) ? es : new Object[1]; |
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} |
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|
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private void initFromPriorityQueue(PriorityQueue<? extends E> c) { |
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if (c.getClass() == PriorityQueue.class) { |
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this.queue = c.toArray(); |
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this.queue = ensureNonEmpty(c.toArray()); |
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this.size = c.size(); |
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} else { |
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initFromCollection(c); |
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for (Object e : es) |
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if (e == null) |
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throw new NullPointerException(); |
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this.queue = es; |
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this.queue = ensureNonEmpty(es); |
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this.size = len; |
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} |
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} |
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/** |
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* The maximum size of array to allocate. |
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* Some VMs reserve some header words in an array. |
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* Attempts to allocate larger arrays may result in |
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* OutOfMemoryError: Requested array size exceeds VM limit |
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*/ |
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private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; |
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/** |
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* Increases the capacity of the array. |
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* |
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* @param minCapacity the desired minimum capacity |
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private void grow(int minCapacity) { |
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int oldCapacity = queue.length; |
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// Double size if small; else grow by 50% |
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int newCapacity = oldCapacity + ((oldCapacity < 64) ? |
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(oldCapacity + 2) : |
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(oldCapacity >> 1)); |
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// overflow-conscious code |
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if (newCapacity - MAX_ARRAY_SIZE > 0) |
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newCapacity = hugeCapacity(minCapacity); |
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int newCapacity = ArraysSupport.newLength(oldCapacity, |
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minCapacity - oldCapacity, /* minimum growth */ |
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oldCapacity < 64 ? oldCapacity + 2 : oldCapacity >> 1 |
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/* preferred growth */); |
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queue = Arrays.copyOf(queue, newCapacity); |
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} |
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private static int hugeCapacity(int minCapacity) { |
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if (minCapacity < 0) // overflow |
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throw new OutOfMemoryError(); |
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return (minCapacity > MAX_ARRAY_SIZE) ? |
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Integer.MAX_VALUE : |
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MAX_ARRAY_SIZE; |
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} |
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|
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/** |
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* Inserts the specified element into this priority queue. |
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* |
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} |
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public E peek() { |
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return (size == 0) ? null : (E) queue[0]; |
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return (E) queue[0]; |
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} |
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private int indexOf(Object o) { |
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} |
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public E poll() { |
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if (size == 0) |
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return null; |
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int s = --size; |
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modCount++; |
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E result = (E) queue[0]; |
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E x = (E) queue[s]; |
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queue[s] = null; |
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if (s != 0) |
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siftDown(0, x); |
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final Object[] es; |
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final E result; |
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|
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if ((result = (E) ((es = queue)[0])) != null) { |
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modCount++; |
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final int n; |
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final E x = (E) es[(n = --size)]; |
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es[n] = null; |
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if (n > 0) { |
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final Comparator<? super E> cmp; |
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if ((cmp = comparator) == null) |
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siftDownComparable(0, x, es, n); |
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else |
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siftDownUsingComparator(0, x, es, n, cmp); |
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} |
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} |
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return result; |
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} |
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*/ |
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E removeAt(int i) { |
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// assert i >= 0 && i < size; |
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final Object[] es = queue; |
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modCount++; |
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int s = --size; |
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if (s == i) // removed last element |
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queue[i] = null; |
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es[i] = null; |
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else { |
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E moved = (E) queue[s]; |
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queue[s] = null; |
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E moved = (E) es[s]; |
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es[s] = null; |
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siftDown(i, moved); |
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if (queue[i] == moved) { |
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if (es[i] == moved) { |
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siftUp(i, moved); |
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if (queue[i] != moved) |
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if (es[i] != moved) |
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return moved; |
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} |
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} |
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private void heapify() { |
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final Object[] es = queue; |
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int n = size, i = (n >>> 1) - 1; |
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Comparator<? super E> cmp = comparator; |
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if (cmp == null) |
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final Comparator<? super E> cmp; |
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if ((cmp = comparator) == null) |
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for (; i >= 0; i--) |
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siftDownComparable(i, (E) es[i], es, n); |
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else |
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// Read in (and discard) array length |
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s.readInt(); |
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|
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SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Object[].class, size); |
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queue = new Object[size]; |
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jsr166.Platform.checkArray(s, Object[].class, size); |
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final Object[] es = queue = new Object[Math.max(size, 1)]; |
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// Read in all elements. |
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final Object[] es = queue; |
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for (int i = 0, n = size; i < n; i++) |
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es[i] = s.readObject(); |
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} |
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/** |
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* @throws NullPointerException {@inheritDoc} |
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*/ |
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public boolean removeIf(Predicate<? super E> filter) { |
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Objects.requireNonNull(filter); |
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return bulkRemove(filter); |
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} |
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|
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/** |
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* @throws NullPointerException {@inheritDoc} |
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*/ |
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public boolean removeAll(Collection<?> c) { |
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Objects.requireNonNull(c); |
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return bulkRemove(e -> c.contains(e)); |
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} |
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|
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/** |
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* @throws NullPointerException {@inheritDoc} |
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*/ |
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public boolean retainAll(Collection<?> c) { |
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Objects.requireNonNull(c); |
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return bulkRemove(e -> !c.contains(e)); |
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} |
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|
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// A tiny bit set implementation |
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|
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private static long[] nBits(int n) { |
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return new long[((n - 1) >> 6) + 1]; |
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} |
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private static void setBit(long[] bits, int i) { |
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bits[i >> 6] |= 1L << i; |
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} |
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private static boolean isClear(long[] bits, int i) { |
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return (bits[i >> 6] & (1L << i)) == 0; |
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} |
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|
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/** Implementation of bulk remove methods. */ |
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private boolean bulkRemove(Predicate<? super E> filter) { |
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final int expectedModCount = ++modCount; |
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final Object[] es = queue; |
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final int end = size; |
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int i; |
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// Optimize for initial run of survivors |
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for (i = 0; i < end && !filter.test((E) es[i]); i++) |
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; |
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if (i >= end) { |
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if (modCount != expectedModCount) |
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throw new ConcurrentModificationException(); |
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return false; |
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} |
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// Tolerate predicates that reentrantly access the collection for |
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// read (but writers still get CME), so traverse once to find |
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// elements to delete, a second pass to physically expunge. |
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final int beg = i; |
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final long[] deathRow = nBits(end - beg); |
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deathRow[0] = 1L; // set bit 0 |
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for (i = beg + 1; i < end; i++) |
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if (filter.test((E) es[i])) |
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setBit(deathRow, i - beg); |
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if (modCount != expectedModCount) |
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throw new ConcurrentModificationException(); |
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int w = beg; |
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for (i = beg; i < end; i++) |
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if (isClear(deathRow, i - beg)) |
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es[w++] = es[i]; |
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for (i = size = w; i < end; i++) |
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es[i] = null; |
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heapify(); |
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return true; |
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} |
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|
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/** |
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* @throws NullPointerException {@inheritDoc} |
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*/ |
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public void forEach(Consumer<? super E> action) { |
