jlab0802.java

经典的生产者和消费者问题

class ProduceInteger extends Thread {
	private HoldInteger sharedObject;
	public ProduceInteger(HoldInteger shared) {
		super("ProduceInteger");
		sharedObject =shared;
	}
	public void run() {
		for(int count =1;count<=10;count++) {
			try {
				Thread.sleep((int)(Math.random()*3000));
			}
			catch(InterruptedException exception) {
				System.err.println( exception.toString());
			}
			sharedObject.setSharedInt(count);
		}
		System.err.println(getName()+"finished producing values"+"\nTerminating "+getName());
	}
}

 class ConsumeInteger extends Thread {
	private HoldInteger sharedObject;
	public ConsumeInteger(HoldInteger shared) {
		super("ConsumeInterger");
		sharedObject=shared;
	}
	public void run() {
		int value,sum=0;
		do {
			try{
				Thread.sleep((int)(Math.random()*3000));
		    } catch(InterruptedException exception) {
			System.err.println(exception.toString());
		    }
		value=sharedObject.getSharedInt();
		sum+=value;
	}while(value!=10);
	System.err.println(getName()+"retrieved values totaling :"+sum+"\nTerminating "+getName());
}
}

 class HoldInteger {
	private int sharedInt=-1;
	private boolean available=false;
	public synchronized  void setSharedInt(int value) {
		while(available==true) {
			try{				
			    wait();
			   } catch(InterruptedException e) {}
	    }
			 
		System.err.println(Thread.currentThread().getName()+"setting sharedInt to"+value);
		sharedInt=value;
		available=true;
		notifyAll();
	    
	}
	public synchronized int getSharedInt() {
		while(available==false) {
			try {
				wait();
			}catch(InterruptedException e) {}
		}
			available=false;
		System.err.println(Thread.currentThread().getName()+"retrieving sharedInt value"+sharedInt);
		notifyAll();
		return sharedInt;
	}
} 

/* class HoldInteger{
	 private int sharedInt=-1;
	 public  void setSharedInt(int value){
	 	 System.out.println(Thread.currentThread().getName()+
	 	                    "setting sharedInt to"+sharedInt);
	 	 sharedInt=value;
   }
    public int getSharedInt(){
    	System.err.println(Thread.currentThread().getName()+
    	                   "retrieving sharedInt value"+sharedInt);
	 	 return sharedInt;
	}
} */	 

public class JLab0802 {
	public static void main(String args[]){
		HoldInteger sharedObject =new HoldInteger();
		ProduceInteger producer =new ProduceInteger(sharedObject);
		ConsumeInteger consumer=new ConsumeInteger(sharedObject);
		producer.start();
		consumer.start();
	}
}