生产，消费者改进

/*
等待的目的是让cpu给其他线程。
*/
class Resource
{
	private String name;
	private int count = 0;
	private boolean flag = false;
	Resource(String name)
	{
		this.name = name;
	}

	public synchronized void product()
	{
		while(flag)						//此处如果是if的效果
		{
			try
			{
				wait();
			}
			catch (InterruptedException ex)
			{
				
			}
		}

		this.name = "---"+this.count;
		System.out.println(Thread.currentThread().getName() + "生产者---" + this.name);
		flag  = true;
		this.count++;
		this.notify();
	}
	
	public synchronized void consume()
	{
		while(!flag)					//此处如果是if的效果,如果某个线程被wait，接着又一个，然后两个都醒了，就会造成对一个产品两次消费
		{
			try
			{
				wait();
			}
			catch (InterruptedException ex)
			{
			}
		}

		System.out.println(Thread.currentThread().getName() + "消费者---------" + this.name);
		flag = false;
		this.notify();
	}
}

class Product implements Runnable
{
	private Resource sr;
	Product(Resource sr)
	{
		this.sr = sr;
	}

	public void run()
	{
		while(true)
		{
			if(sr != null)
			{
				sr.product();
			}
		}
	}
}

class Consume implements Runnable
{
	private Resource sr;
	Consume(Resource sr)
	{
		this.sr = sr;
	}

	public void run()
	{
		while(true)
		{
			if(sr != null)
			{
				sr.consume();
			}
		}
	}
}
class DemoRunnable
{
	public static void main(String[] args) 
	{
		Resource sr = new Resource("产品");
		Product p = new Product(sr);
		Consume c =new Consume(sr);
		Thread t1 = new Thread(p);
		Thread t2 = new Thread(p);
		Thread c1 = new Thread(c);
		Thread c2 = new Thread(c);
		Thread c3 = new Thread(c);
		t1.start();
		t2.start();
		c1.start();
		c2.start();
		c3.start();
	}
}