import java.util.Observable;
import java.util.Observer;
class Watcher1 implements Observer {
public void update(Observable obj, Object arg) {
System.out.println("update() called, count is " + ((Integer) arg).intValue());
}
}
class Watcher2 implements Observer {
public void update(Observable obj, Object arg) {
if (((Integer) arg).intValue() == 0)
System.out.println("Done");
}
}
class BeingWatched extends Observable {
void counter(int period) {
for (; period >= 0; period--) {
setChanged();
notifyObservers(new Integer(period));
try {
Thread.sleep(100);
} catch (InterruptedException e) {
System.out.println("Sleep interrupted");
}
}
}
}
class MainClass {
public static void main(String args[]) {
BeingWatched observed = new BeingWatched();
Watcher1 observing1 = new Watcher1();
Watcher2 observing2 = new Watcher2();
observed.addObserver(observing1);
observed.addObserver(observing2);
observed.counter(10);
}
}