生产者_消费者

线程之间，通过wait() notify() notifyAll()来协作编程；

1. 必须在synchronized方法或方法块中使用

2. 与Thread.sleep()的区别：wait()方法释放持有的对象的锁。

3. 属于Object类的方法

4. 替代类：java.util.concurrent.locks.Condition  接口

5. 经典举例，生产者/消费者：餐馆有一个厨师负责生产食物，一个服务员负责上菜（消费食物）；服务员必须在厨师生产完食物后工作，未生产完成时等待；系统必须有序的停止。

a)食物类：

class Meal {
	private final int orderNum;

	public Meal(int orderNum) {
		this.orderNum = orderNum;
	}

	@Override
	public String toString() {
		return "Meal : " + orderNum;
	}
	
}

b)厨师：

class Chef implements Runnable {
	
	private Restaurant res;
	private int count = 0;
	
	public Chef(Restaurant res) {
		this.res = res;
	}
	
	@Override
	public void run() {
		try {
			while(!Thread.interrupted()) {
				synchronized (this) {
					if(null != res.getMeal()) {
						wait();
					}
				}
				if(++count > 10) {
					System.out.println("Out of food, close! ");
					res.getExec().shutdownNow();  //通知wait收工
					throw(new InterruptedException());  //自己收工
				}
				System.out.print("Order up! ");
				synchronized (res.getWaitPerson()) {
					res.setMeal(new Meal(count));
					res.getWaitPerson().notifyAll();
				}
				TimeUnit.MICROSECONDS.sleep(100);
			}
		} catch(InterruptedException e) {
			System.out.println("Chef interrupted! ");
		}
	}
	
}

class WaitPerson implements Runnable {
	
	private Restaurant res;
	
	public WaitPerson(Restaurant res) {
		this.res = res;
	}

	@Override
	public void run() {
		try {
			while(!Thread.interrupted()) {
				synchronized (this) {
					if(null == res.getMeal()) {
						wait();
					}
				}
				System.out.println("WaitPerson got " + res.getMeal());
				synchronized (res.getChef()) {
					res.setMeal(null);    //上酸菜
					res.getChef().notifyAll();  //通知厨师准备下一份
				}
			}
		} catch(InterruptedException e) {
			System.out.println("WaitPerson interrupted! ");
		}
	}
	
}

public class Restaurant {
	
	private Meal meal;
	private Chef chef = new Chef(this);
	private WaitPerson waitPerson = new WaitPerson(this);
	private ExecutorService exec = Executors.newCachedThreadPool();
	
	public Restaurant() {
		exec.execute(chef);
		exec.execute(waitPerson);
	}

	public Meal getMeal() {
		return meal;
	}

	public void setMeal(Meal meal) {
		this.meal = meal;
	}

	public Chef getChef() {
		return chef;
	}

	public WaitPerson getWaitPerson() {
		return waitPerson;
	}

	public ExecutorService getExec() {
		return exec;
	}

	public static void main(String[] args) {
		new Restaurant();
	}
}

//output
Order up! WaitPerson got Meal : 1
Order up! WaitPerson got Meal : 2
Order up! WaitPerson got Meal : 3
Order up! WaitPerson got Meal : 4
Order up! WaitPerson got Meal : 5
Order up! WaitPerson got Meal : 6
Order up! WaitPerson got Meal : 7
Order up! WaitPerson got Meal : 8
Order up! WaitPerson got Meal : 9
Order up! WaitPerson got Meal : 10
Out of food, close! 
Chef interrupted! 
WaitPerson interrupted! 

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生产者_消费者

原文：http://blog.csdn.net/y172158950/article/details/21158291