The interface definition for a PureMVC Observer.

In PureMVC, IObserver implementors assume 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 interested object' notification method and context.
• Provide a method for notifying the interested object.

PureMVC does not rely upon underlying event models such as the one provided with Flash.

The Observer Pattern as implemented within PureMVC exists to support event driven communication between the application and the actors of the MVC triad.

An Observer is an object that encapsulates information about an interested object with a notification method that should be called when an INotification is broadcast. The Observer then acts as a proxy for notifying the interested object.

Observers can receive Notifications by having their notifyObserver method invoked, passing in an object implementing the INotification interface, such as a subclass of Notification.