File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
The moose likes Beginning Java and the fly likes What is Observer and Observable? Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login

Win a copy of EJB 3 in Action this week in the EJB and other Java EE Technologies forum!
JavaRanch » Java Forums » Java » Beginning Java
Bookmark "What is Observer and Observable?" Watch "What is Observer and Observable?" New topic

What is Observer and Observable?

Hemant Agarwal
Ranch Hand

Joined: Nov 21, 2005
Posts: 138
What is Observer and Observable? What is their use?
fred rosenberger
lowercase baba

Joined: Oct 02, 2003
Posts: 10908

They're part of the Observer pattern. you have one object that notifies a bunch of others when needed. many "observers" may register with an "observable", and all may un-register.

Check out the Head First Design Patterns book, or google "design patterns observer" and you'll find tons of into...

There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors
Ulf Dittmer

Joined: Mar 22, 2005
Posts: 39541
There's a good IBM Developerworks tutorial on event delivery techniques, which you can find here. It covers Observer/Observable, JavaBean event techniques and more.
[ January 01, 2006: Message edited by: Ulf Dittmer ]

Ping & DNS - updated with new look and Ping home screen widget
I agree. Here's the link:
subject: What is Observer and Observable?
Similar Threads
What are Observer and Observable? How it is usfull?
a doubt regarding course
Observer and Observable
How to write my own Event ( & Listener for it)??