dining.java

这是清华大学编写的JAVA教材中所有题目的源代码！

class ChopStick
{
	boolean available;
	
	ChopStick()
	{ available=true; }
	
	public synchronized void takeup(int philo_num,String lf)
	{
		while(!available)
		{
			try
			{
				System.out.println("哲学家"+(philo_num+1)+"等待"+lf+"筷子");
				wait();
			}
			catch(InterruptedException e){}
		}
		System.out.println("哲学家"+(philo_num+1)+"拿起"+lf+"筷子");
		available=false;
	}
	
	public synchronized void putdown(int philo_num,String lf)
	{
		System.out.println("哲学家"+(philo_num+1)+"放下"+lf+"筷子");
		available=true;
		notify();
	}
}
	
class Philosopher extends Thread
{
	ChopStick left,right;
	int philo_num;
	
	Philosopher(int num,ChopStick l,ChopStick r)
	{
		philo_num=num;
		left=l;
		right=r;
	}
	
	public void eat()
	{
		left.takeup(philo_num,"左边");
		right.takeup(philo_num,"右边");
		System.out.println("哲学家"+(philo_num+1)+"正在进餐");
	}
	
	public void think()
	{
		left.putdown(philo_num,"左边");
		right.putdown(philo_num,"右边");
		System.out.println("哲学家"+(philo_num+1)+"正在思考");
	}
	
	public void run()
	{
		while(true)
		{
			eat();
			
			try{ sleep(1000); }
			catch(InterruptedException e){}
			
			think();
			
			try{ sleep(1000); }
			catch(InterruptedException e){}
		}
	}
}
	
public class Dining
{
	static ChopStick[] chopsticks=new ChopStick[5];
	static Philosopher[] philos=new Philosopher[5];
	
	public static void main(String args[])
	{
		for(int i=0;i<5;i++)
			chopsticks[i]=new ChopStick();
		
		for(int i=0;i<5;i++)
			philos[i]=new Philosopher(i,chopsticks[i],chopsticks[(i+1)%5]);
			
		for(int i=0;i<5;i++)
			philos[i].start();
	}
}