simplequeue.java

Messaging- MIDP的是一个彩信客户端

/*
 *  JVending - J2ME MMS Client
 *  Copyright (C) 2004  Shane Isbell
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package org.jvending.messaging.impl.mms;

/**
 * @author Shane Isbell
 * @version 1.0.0a
 * @created 04/03/27
 */

public class SimpleQueue {

    private int buffersize;

    private Object[] buffer;

    private int front;

    private int rear;

    public SimpleQueue(int buffersize) {
        this.buffersize = buffersize;
        buffer = new Object[buffersize];
    }

    public void enqueue(Object x) throws IndexOutOfBoundsException {
        rear = (rear == buffersize) ? 0: rear;
        buffer[rear++] = x;
    }

    public boolean isEmpty() {
        return front == rear;
    }

    public Object dequeue() throws IndexOutOfBoundsException {
        front = (front == buffersize) ? 0: front;
        return buffer[front++];
    }
 
    //this peeks across the entire buffer, even if consumed.
    public Object peek(int peekValue) throws IndexOutOfBoundsException {
        if (peekValue > buffersize) throw new IndexOutOfBoundsException();
        return buffer[peekValue];    
    }
}