//【例7.6】  發送線程與接收線程。

public class Buffer                    //緩沖區
{
    private int value;                 //共享變量
    public void put(int i)
    {
       value = i;
    }
    public int get()
    {
       return value;
    }
}

class Sender extends Thread            //發送線程類
{
    private Buffer buffer;             //用于交換數據的共享變量
    
    public Sender(Buffer buffer)       //指定緩沖區
    {
        this.buffer = buffer;
    }
    
    public void run()
    {
        for (int i=1;i<6;i++)          //連續向緩沖區發送若干數據
        {
            buffer.put( i );
            System.out.println("Sender  put : " + i );

            try
            {
                 sleep(1);
            }
            catch(InterruptedException e) {}
        }
    }
}

class Receiver extends Thread          //接收線程類
{
    private Buffer buffer;
    
    public Receiver(Buffer buffer)     //指定緩沖區
    {
        this.buffer = buffer ;
    }
    
    public void run()        
    {
        for (int i=1; i<6;i++)         //連續從緩沖區接收若干數據
        {
            System.out.println("\t\t\tReceiver get : " + buffer.get()) ;
            
            try
            {
                 sleep(1);
            }
            catch(InterruptedException e) {}
        }
    }

    public static void main(String args[])
    {
        Buffer buffer = new Buffer();
        (new Sender(buffer)).start();
        (new Receiver(buffer)).start();
    }

}

/*
沒有sleep(1)語句時，程序運行結果如下：
Sender  put : 1
Sender  put : 2
Sender  put : 3
Sender  put : 4
Sender  put : 5

    			Receiver get : 5
    			Receiver get : 5
    			Receiver get : 5
    			Receiver get : 5
    			Receiver get : 5


有sleep(1)方法時，每次運行結果不確定，交替執行，間隔輸出，一種可能的運行結果如下：
Sender  put : 1
    			Receiver get : 1
Sender  put : 2
    			Receiver get : 2
Sender  put : 3
Sender  put : 4
    			Receiver get : 4
Sender  put : 5
    			Receiver get : 5
    			Receiver get : 5
*/