#language en
= Observer Pattern =

'''Intent:''' Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.

Described in Wiki:ObserverPattern.

Common incarnations of the Observer Pattern use events to notify observers about changes in the subject. A python solution that encapsulates event triggering and subscription and mimics C#-style events can be found [[http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/410686|here]].

== Discussion ==