Showing the changes to java/pkg/com/sun/jmx/remote/internal/ArrayQueue.java (1 of 18352 files). Show all
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| 1 | +/* | |
| 2 | + * Copyright (c) 2003, 2006, 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 | |
| 6 | + * under the terms of the GNU General Public License version 2 only, as | |
| 7 | + * published by the Free Software Foundation. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +package com.sun.jmx.remote.internal; | |
| 27 | + | |
| 28 | +import java.util.AbstractList; | |
| 29 | +import java.util.Iterator; | |
| 30 | + | |
| 31 | +public class ArrayQueue<T> extends AbstractList<T> { | |
| 32 | + public ArrayQueue(int capacity) { | |
| 33 | + this.capacity = capacity + 1; | |
| 34 | + this.queue = newArray(capacity + 1); | |
| 35 | + this.head = 0; | |
| 36 | + this.tail = 0; | |
| 37 | + } | |
| 38 | + | |
| 39 | + public void resize(int newcapacity) { | |
| 40 | + int size = size(); | |
| 41 | + if (newcapacity < size) | |
| 42 | + throw new IndexOutOfBoundsException("Resizing would lose data"); | |
| 43 | + newcapacity++; | |
| 44 | + if (newcapacity == this.capacity) | |
| 45 | + return; | |
| 46 | + T[] newqueue = newArray(newcapacity); | |
| 47 | + for (int i = 0; i < size; i++) | |
| 48 | + newqueue[i] = get(i); | |
| 49 | + this.capacity = newcapacity; | |
| 50 | + this.queue = newqueue; | |
| 51 | + this.head = 0; | |
| 52 | + this.tail = size; | |
| 53 | + } | |
| 54 | + | |
| 55 | + @SuppressWarnings("unchecked") | |
| 56 | + private T[] newArray(int size) { | |
| 57 | + return (T[]) new Object[size]; | |
| 58 | + } | |
| 59 | + | |
| 60 | + public boolean add(T o) { | |
| 61 | + queue[tail] = o; | |
| 62 | + int newtail = (tail + 1) % capacity; | |
| 63 | + if (newtail == head) | |
| 64 | + throw new IndexOutOfBoundsException("Queue full"); | |
| 65 | + tail = newtail; | |
| 66 | + return true; // we did add something | |
| 67 | + } | |
| 68 | + | |
| 69 | + public T remove(int i) { | |
| 70 | + if (i != 0) | |
| 71 | + throw new IllegalArgumentException("Can only remove head of queue"); | |
| 72 | + if (head == tail) | |
| 73 | + throw new IndexOutOfBoundsException("Queue empty"); | |
| 74 | + T removed = queue[head]; | |
| 75 | + queue[head] = null; | |
| 76 | + head = (head + 1) % capacity; | |
| 77 | + return removed; | |
| 78 | + } | |
| 79 | + | |
| 80 | + public T get(int i) { | |
| 81 | + int size = size(); | |
| 82 | + if (i < 0 || i >= size) { | |
| 83 | + final String msg = "Index " + i + ", queue size " + size; | |
| 84 | + throw new IndexOutOfBoundsException(msg); | |
| 85 | + } | |
| 86 | + int index = (head + i) % capacity; | |
| 87 | + return queue[index]; | |
| 88 | + } | |
| 89 | + | |
| 90 | + public int size() { | |
| 91 | + // Can't use % here because it's not mod: -3 % 2 is -1, not +1. | |
| 92 | + int diff = tail - head; | |
| 93 | + if (diff < 0) | |
| 94 | + diff += capacity; | |
| 95 | + return diff; | |
| 96 | + } | |
| 97 | + | |
| 98 | + private int capacity; | |
| 99 | + private T[] queue; | |
| 100 | + private int head; | |
| 101 | + private int tail; | |
| 102 | +} | |