# 112 - Learning the Observer Pattern w/ Callbacks

Date: 5/21/2009

Level: Intermediate

Author: Derik Whittaker

Tags: Design Patterns

Views: (4441) Watched: (4662)

In this episode we will take at how we can use the Observer Pattern in our application.

This is a follow up episode to Episode 108 where we take another look at this pattern and how we can implement it using either call backs or events. The Observer pattern allows you to define a one-to-many relationship inside your application where the parent object (the one) has the ability to notify the child objects (the many) of any state change. You can utilize this pattern to make sure that a set of objects are keep in order when there behavior needs to change based on the state of your application.
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