Uncle Bob's Agile Development Corner
OBSERVEREvolving into a pattern, Part 2
by Robert C. Martin
Listing 1. TimeSource.java.
public class TimeSource
private Vector itsObservers = new Vector();
protected void notify(int hours, int minutes, int seconds)
Iterator i = itsObservers.iterator();
ClockObserver observer = (ClockObserver) i.next();
observer.update(hours, minutes, seconds);
public void registerObserver(ClockObserver observer)
Robert C. Martin is president of Object Mentor Inc., a firm that offers high-level, OO software design consulting, training, and development services. He is the author of Designing Object Oriented C++ Applications Using the Booch Method. He can be contacted at firstname.lastname@example.org.