Top Highlights

• suppose we don’t care about an object’s class, but we do care that it conforms to MYProtocol.
• Models contain all of the rules for processing application data. The Model is the key subsystem that makes an application valuable. It’s critically important that the Model subsystem is able to stand alone without dependencies on either the View or Controller subsystems.
• The purpose of the Controller is to decouple the Model from the Views.
• A Model may store objects in an unordered collection, but the Controller may sort the objects before providing them to a View for presentation to a user.
• The Model objects might constrain the updated values to fall within application defined limits or perform other validation.