An inside view of Observer
The Observer pattern facilitates communication between decoupled objects
By David Geary, JavaWorld.com, 03/28/03
Page 6 of 6
- Maintain a collection of listeners
- Implement
addPropertyChangeListener()
- Notify listeners when a bound property changes
Once you implement the above steps, you can add property change listeners to your event source and react to events.
Listen and observe
The Observer design pattern is one of the most fundamental design patterns because it allows loosely coupled objects to communicate.
That ability lets you create pluggable components, which lie at the heart of object-oriented extensibility and reuse.
About the author
David
Geary is the author of
Core JSTL Mastering the JSP Standard Tag Library (Prentice
Hall, 2002; ISBN: 0131001531),
Advanced JavaServer Pages (Prentice Hall, 2001; ISBN:
0130307041), and the
Graphic Java series (Prentice Hall). David has been
developing object-oriented software with numerous object-oriented
languages for 18 years. Since the GOF Design Patterns book
was published in 1994, David has been an active proponent of design
patterns, and has used and implemented design patterns in
Smalltalk, C++, and Java. In 1997, David began working full-time as
an author and occasional speaker and consultant. David is a member
of the expert groups defining the JSP Standard Tag Library and
JavaServer Faces, and is a contributor to the Apache Struts JSP
framework.
Read more about Core Java in JavaWorld's Core Java section.