Design Patterns: Model View Controller Emerson Murphy-Hill

Model-View-Controller (MVC) MVC Pattern: Isolates business or domain logic from the input and presentation Can focus testing on the individual pieces Model: behavior and data underlying the application Provides data about state requested from the view (notifies the view) Updates state when requested by the controller Model abstracts and encapsulates the underlying data storage (DB, POJOs, etc.) View: UI A model may have many views View is a composite of elements Controller: receives input and initiates response by calling model Strategy for the view

MVC in Web Apps (like iTrust) View: HTML or XHTML Generated by JSPs Controller: Action classes Pass user input to model Handle exceptions Model: underlying domain logic Beans and DAOs encapsulate the database