How to create a block method?

[Anza Power]

I want to implement something that looks like this:

while(true){
	waitForSignal();
	//do the code
}

How do I make the waitForSignal() method? I want that method to block the current thread until another method calls a certain method to give it the signal (namely, a button being pressed in the GUI app)

Is there a good up-to-date book/tutorial you'd recommend for getting good control of java concurrency?

[doWhile]

Are you familiar with the wait/notify methods? Guarded Blocks (The Java™ Tutorials > Essential Classes > Concurrency)

[Anza Power]

^ I came across that page while doing the search on my own before posting, it kept failing for me and giving me an IllegalMonitorStateException, silly me that was because I was calling the notify() method that belonged to the anonymous ActionListener class attached to the button and not the main class of the program on which I invoke the wait() method...

Thanks for your help...:)

[JosAH]

A wait or notifty(All) call on an object only works if the caller holds the 'monitor' for that object; so:

// in one thread:
synchronized(anObject) { // get the monitor of anObject
   while (!aCondition()) anObject.wait(); // wait on anObject
}

// while in another thread:
synchronize(anObject) { // get the monitor on the same 'anObject'
   // make aCondition return true
   anObject.notifyAll(); // wake up all waiting threads
}

kind regards,

Jos

[Anza Power]

^ Yeah I know, my problem was that I wrote it like this:

myButton.addActionListener(new ActionListener(){
	public void actionPerformed(ActionEvent ae){
		startExecution = true;
		notifyAll();
	}
}

I didn't notice that I was calling the notifyAll() method that belonged to the ActionListener object and not the containing object on which I call the wait() method...