simplequeue.java

来自「用Java写的彩信的程序。包括wsp／mime／mms几部分。」· Java 代码 · 共 51 行

/* 
 * JVending - J2ME MMS Client
 *
 * Distributed under Apache style software license included with the source code.
 */

package org.jvending.messaging.util;

import java.util.NoSuchElementException;

/**
 * @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];    
    }
}