Object's Lock

[Marcelo Ortega]

 
class Storage{
    
    private int val;
    
    synchronized int getVal(){
        try{
            this.wait();
        }
        catch(InterruptedException ex){}
        return val;
    }
    
    synchronized void setVal(int val){
        this.notify();
        this.val = val;
    }
    
}
 
class Counter implements Runnable{
    
    private Storage store;
    private Thread t1;
    
    Counter(String name, Storage store){
        this.store = store;
        t1 = new Thread(this,name);
        t1.start();
    }
    
    public void run(){
        
        try{
            for(int i=0; i<=10; i++){
                store.setVal(i);
                Thread.sleep(300);
            }
        }
        catch(InterruptedException ex){}
    }
    
}
 
 
class Printer implements Runnable{
 
    private Storage store;
    private Thread t2;
    
    Printer(String name, Storage store){
        this.store = store;
        t2 = new Thread(this,name);
        t2.start();
    }
    
    
    public void run(){
        
        try{
            for(int i=0; i<=10; i++){
                System.out.println(store.getVal());            
                Thread.sleep(300);
            }        
        }
        catch(InterruptedException ex){}
    }   
    
}
 
public class Main{        
    public static void main(String[] args){
        Storage store = new Storage();
        Counter count = new Counter("Counter", store);
        Printer print = new Printer("Printer", store);
        
        System.out.println("Yielding...");
        Thread.yield();
        
        System.out.println("End main thread...");
    }
} 
 

Are the notify() and wait() methods implemented correctly? I was expecting the output to be from 0 to 10 with no double nor numbers missing, but i am actually get doubles AND number missing...
[ July 07, 2005: Message edited by: Barry Gaunt ]

[janki tangeda]

I have just started reading on java threads and i have a question on the code you wrote.Don't we use wait() method to wait for some condition to be met.I don't see any such condition here.For e.g. in getValue() method, is it not required to check if the value is updated and wait until the updating is done.