Re: How to use wait() and notifyAll() in simple container object

Hello all,

I have a simple container object that has a get and set method for a
variable it contains. Multiple threads will potentially be accessing
the container object to get and set the variable. Can anyone tell me
what's wrong with the code I have below? It's not working for me...

public class Container {

    private boolean value = false;
    private boolean available = false;

    public Container(boolean value) {
        this.value = value;
    }

    public synchronized boolean get() {
        while (available == false) {
            try {
                wait();
            } catch (InterruptedException ex) { ex.printStackTrace(); }
        }
        available = false;
        notifyAll();
        return value;
    }

    public synchronized void set(boolean value) {
        while (available == true) {
            try {
                wait();
            } catch (InterruptedException ex) { ex.printStackTrace(); }
        }
        this.value = value;
        available = true;
        notifyAll();
    }
}

I found most of the above code in a tutorial on the web --
http://www.janeg.ca/scjp/threads/synchronized.html -- but like I said
it's not working for me. Here's how I'm testing it:

I have a class that extends TimerTask and is called every 5 seconds to
randomize the value by calling the set method and passing it a random
boolean value obtained from Random.nextBoolean(). I have it set up to
print to the console each time it changes the value... it prints one
time but never prints again. Any suggestions as to why this isn't
working for me?

Thanks!