Uncle Bob's Agile Development Corner
OBSERVER—Evolving into a pattern, Part 2
by Robert C. Martin
Listing 1. TimeSource.java.

import java.util.*;

public class TimeSource
    private Vector itsObservers = new Vector();

    protected void notify(int hours, int minutes, int seconds)
        Iterator i = itsObservers.iterator();
        while (i.hasNext())
            ClockObserver observer = (ClockObserver) i.next();
            observer.update(hours, minutes, seconds);

    public void registerObserver(ClockObserver observer)

About the Author

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 rmartin@objectmentor.com.


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