Model-View-Controller
Stores application state data.
Stateless pages that transform model data into a form appropriate for display to the user, such as HTML, WAP or XML.
Process user input, update the model, and choose views (Figure A-6).
The controller receives the user input, and translates it into appropriate updates to the model. The model applies business rules and stores the data persistently, either locally, in the business tier, or using some other remote persistence mechanism. Based on the model changes and user input, the controller chooses a view. The view transforms the updated model data into a form suitable for the user.