Queue(队列)是一种特殊类型的集合，旨在使用先进先出方式处理和排序之前保存元素。
下面使用 Array 实现 Queue，并提供诸如enqueue(obj)，dequeue()和isEmpty()等基本功能。
代码语言：javascript复制/**
* <p></p>
*
* @author 三产
* @version 1.0
* @date 2017-03-24
* @QQGroup 213732117
* @website http://www.coderknock.com
* @copyright Copyright 2017 拿客 coderknock.com All rights reserved.
* @since JDK 1.8
*/
public class MyQueue {
//CONSTRUCTION: with no initializer
//
// ******************PUBLIC OPERATIONS*********************
// void enqueue( obj ) --> Insert obj
// Object dequeue( ) --> Return and remove least recent item
// boolean isEmpty( ) --> Return true if empty; else false
public static final int DEFAULT_SIZE=5;
private Object data[];
private int index;
public MyQueue(){
data=new Object[DEFAULT_SIZE];
}
public boolean isEmpty(){
return index==0;
}
public void enqueue(Object obj) throws Exception{
if(index==DEFAULT_SIZE-1){
throw new Exception("Queue is full. Dequeue some objects");
}
this.data[index]=obj;
this.index ;
}
public Object dequeue() throws Exception{
if(isEmpty())throw new Exception("Queue is empty");
Object obj=this.data[0];
for(int i =0; i<this.index-1; i ){
data[i]=data[i 1];
}
this.index--;
return obj;
}
public static void main(String[] args) throws Exception {
MyQueue queue = new MyQueue();
queue.enqueue("1");
System.out.println(queue.dequeue());
queue.enqueue("2");
queue.enqueue("3");
queue.enqueue("4");
System.out.println(queue.dequeue());
queue.enqueue("5");
queue.enqueue("6");
System.out.println(queue.dequeue());
queue.enqueue("7");
/**
* 这里是队列超出默认大小的时候会抛出的异常
* Exception in thread "main" java.lang.Exception: Queue is full. Dequeue some objects
* at MyQueue.enqueue(MyQueue.java:37)
* at MyQueue.main(MyQueue.java:69)
*/
queue.enqueue("8");
System.out.println(queue.dequeue());
}
}
