public class SubjectImpl implements Subject {
  public SubjectImpl() { itsObservers = new java.util.Vector(); }
  public void Register(Observer o) { itsObservers.addElement(o); }
  public void Notify() {
    java.util.Enumeration i = itsObservers.elements();
    while ( i.hasMoreElements() ) {
      Observer o = (Observer)(i.nextElement());
      o.Update();
    }
  }
  private java.util.Vector itsObservers;
}