import java.util.*;

/**
 * A simple demo of Observable->Observer
 *
 * @author Ian Darwin
 * @version $Id: ObservDemo.java,v 1.3 2003/12/29 19:52:22 ian Exp $
 */
public class ObservDemo extends Object {
	MyView view;
	MyModel model;

	public ObservDemo() {

		view = new MyView();

		model = new MyModel(); 
		model.addObserver(view);

	}

	public static void main(String[] av) {
		ObservDemo me = new ObservDemo();
		me.demo();
	}

	public void demo() {
		model.changeSomething();
	}

	/** The Observer normally maintains a view on the data */
	class MyView implements Observer {
		/** For now, we just print the fact that we got notified. */
		public void update( Observable obs, Object x ) {
			System.out.println("update(" + obs + "," + x + ");");
		}
	}

	/** The Observable normally maintains the data */
	class MyModel extends Observable {
		public void changeSomething() {
			// Notify observers of change
			setChanged();
			notifyObservers();
		}
	}
}