observer.rb

An Observer is an object that encapsulates information about an interested object with a method that should be called when a particular Notification is broadcast.

In PureMVC, the Observer class assumes these responsibilities:

• Encapsulate the notification (callback) method of the interested object.
• Encapsulate the notification context (this) of the interested object.
• Provide methods for setting the notification method and context.
• Provide a method for notifying the interested object.