1 package dynaop.observer;2 3 /**4 * Observes a <code>Subject</code>.5 * 6 * @author Bob Lee (crazybob@crazybob.org)7 */8 public interface Observer {9 10 /**11 * Notifies of change in the <code>Subject</code>.12 */13 void notify(Subject subject, Object argument);14 }