帮朋友Every写的消费者的例子

朋友Every今天问我，线程到底怎么控制？消费者模式怎么写？

于是，我给他写了一个生产消费蛋糕的例子，贴出来分享一下。

/**
 * 演示消费者模式
 */
package com.godway.custom;

import java.util.concurrent.ConcurrentLinkedQueue;

/**
 * @author 高伟
 * @date Jan 6, 2012 1:40:07 PM
 * @description: 
 * 
 * 演示蛋糕的生产过程。
 */
public class CakeExample {
	
	public static void main(String[] args) {
		
		/**
		 * 池子
		 * 蛋糕箱子
		 * 所有机器产生的蛋糕都放到这里
		 * 所有人吃蛋糕都从这里取
		 * 
		 * ConcurrentLinkedQueue:采用线程同步的队列
		 */
		ConcurrentLinkedQueue<Cake> cakeList = new ConcurrentLinkedQueue<Cake>();
		
		/**
		 * 生产者
		 * 机器，生产蛋糕
		 * 五个工厂应该够咱俩吃
		 */
		Machine machine1 = new Machine ("machine1",cakeList);
		Machine machine2 = new Machine ("machine2",cakeList);
		Machine machine3 = new Machine ("machine3",cakeList);
		Machine machine4 = new Machine ("machine4",cakeList);
		Machine machine5 = new Machine ("machine5",cakeList);
		
		/**
		 * 消费者
		 * 人，吃蛋糕
		 */
		Person gaogao = new Person("gaogao",cakeList);
		Person every = new Person("every",cakeList);
		
		/**
		 * 启动
		 */
		new Thread(machine1).start();
		new Thread(machine2).start();
		new Thread(machine3).start();
		new Thread(machine4).start();
		new Thread(machine5).start();
		
		new Thread(gaogao).start();
		new Thread(every).start();
	}
	
	
	
}

/**
 * 蛋糕实体
 * @author 高伟
 * @date Jan 6, 2012 1:43:01 PM
 * @description:
 */
class Cake{
	private int id;
	public Cake(int id) {
		this.id = id;
	}
	@Override
	public String toString() {
		return id+"";
	}
}

/**
 * 制作蛋糕机器
 * @author 高伟
 * @date Jan 6, 2012 1:43:43 PM
 * @description:
 */
class Machine implements Runnable{
	
	private String isbn;
	private ConcurrentLinkedQueue<Cake> cakeList;
	private static int count = 0; 
	
	public Machine(String isbn,ConcurrentLinkedQueue<Cake> cakeList) {
		this.isbn = isbn;
		this.cakeList = cakeList;
	}
	
	public void run(){
		while(true){
			synchronized (cakeList) {
				Cake cake = new Cake(count++);
				cakeList.add(cake);
				System.out.printf("Machine (%s) create cake (%s).Total: (%s). Remain: (%s) \n", isbn, cake, count, cakeList.size());
				cakeList.notify();
			}
			try {
				//生产蛋糕需要消耗5秒的时间
				Thread.sleep(5000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
	
	@Override
	public String toString() {
		return isbn;
	}
}

/**
 * 吃蛋糕
 * @author 高伟
 * @date Jan 6, 2012 1:49:36 PM
 * @description:
 */
class Person implements Runnable{
	private String name;
	private ConcurrentLinkedQueue<Cake> cakeList;
	
	public Person(String name,ConcurrentLinkedQueue<Cake> cakeList) {
		this.name = name;
		this.cakeList = cakeList;
	}
	
	public void run( ){
		while(true){
			synchronized (cakeList) {
				if(cakeList.size()==0){
					try {
						cakeList.wait();
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
				Cake cake = cakeList.poll();
				System.out.printf("Cake (%s) is eated by person (%s).\n" , cake, this);
				
			}
			try {
				//吃掉蛋糕也需要1秒的时间
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
	
	@Override
	public String toString() {
		return name;
	}
}