Introduction to OOP

Chapter 24: Design Patterns :

Observer

Problem: How do you dynamically (at run time) add and remove connections between objects.

Solution: An Observer Manager implements the following protocol:

``I Want to Observe X'' -- the OM will keep track of who is watching who
``Tell Everybody who is Observing Met that I have Changed'' -- the OM can then tell everybody that an object has changed.

In this way neither the observer nor the observed object need know the existance of the other.