/* * Copyright (c) 2003, 2006, 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 * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */package com.sun.jmx.remote.internal;import java.util.AbstractList;import java.util.Iterator;public class ArrayQueue<T> extends AbstractList<T> { public ArrayQueue(int capacity) { this.capacity = capacity + 1; this.queue = newArray(capacity + 1); this.head = 0; this.tail = 0; } public void resize(int newcapacity) { int size = size(); if (newcapacity < size) throw new IndexOutOfBoundsException("Resizing would lose data"); newcapacity++; if (newcapacity == this.capacity) return; T[] newqueue = newArray(newcapacity); for (int i = 0; i < size; i++) newqueue[i] = get(i); this.capacity = newcapacity; this.queue = newqueue; this.head = 0; this.tail = size; } @SuppressWarnings("unchecked") private T[] newArray(int size) { return (T[]) new Object[size]; } public boolean add(T o) { queue[tail] = o; int newtail = (tail + 1) % capacity; if (newtail == head) throw new IndexOutOfBoundsException("Queue full"); tail = newtail; return true; // we did add something } public T remove(int i) { if (i != 0) throw new IllegalArgumentException("Can only remove head of queue"); if (head == tail) throw new IndexOutOfBoundsException("Queue empty"); T removed = queue[head]; queue[head] = null; head = (head + 1) % capacity; return removed; } public T get(int i) { int size = size(); if (i < 0 || i >= size) { final String msg = "Index " + i + ", queue size " + size; throw new IndexOutOfBoundsException(msg); } int index = (head + i) % capacity; return queue[index]; } public int size() { // Can't use % here because it's not mod: -3 % 2 is -1, not +1. int diff = tail - head; if (diff < 0) diff += capacity; return diff; } private int capacity; private T[] queue; private int head; private int tail;}
/*
* Copyright (c) 2003, 2006, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package com.sun.jmx.remote.internal;
import java.util.AbstractList;
import java.util.Iterator;
public class ArrayQueue<T> extends AbstractList<T> {
public ArrayQueue(int capacity) {
this.capacity = capacity + 1;
this.queue = newArray(capacity + 1);
this.head = 0;
this.tail = 0;
}
public void resize(int newcapacity) {
int size = size();
if (newcapacity < size)
throw new IndexOutOfBoundsException("Resizing would lose data");
newcapacity++;
if (newcapacity == this.capacity)
return;
T[] newqueue = newArray(newcapacity);
for (int i = 0; i < size; i++)
newqueue[i] = get(i);
this.capacity = newcapacity;
this.queue = newqueue;
this.head = 0;
this.tail = size;
}
@SuppressWarnings("unchecked")
private T[] newArray(int size) {
return (T[]) new Object[size];
}
public boolean add(T o) {
queue[tail] = o;
int newtail = (tail + 1) % capacity;
if (newtail == head)
throw new IndexOutOfBoundsException("Queue full");
tail = newtail;
return true; // we did add something
}
public T remove(int i) {
if (i != 0)
throw new IllegalArgumentException("Can only remove head of queue");
if (head == tail)
throw new IndexOutOfBoundsException("Queue empty");
T removed = queue[head];
queue[head] = null;
head = (head + 1) % capacity;
return removed;
}
public T get(int i) {
int size = size();
if (i < 0 || i >= size) {
final String msg = "Index " + i + ", queue size " + size;
throw new IndexOutOfBoundsException(msg);
}
int index = (head + i) % capacity;
return queue[index];
}
public int size() {
// Can't use % here because it's not mod: -3 % 2 is -1, not +1.
int diff = tail - head;
if (diff < 0)
diff += capacity;
return diff;
}
private int capacity;
private T[] queue;
private int head;
private int tail;
}