GWT and MVP

Getting a handle on GWT and MVP.

MVP=Model-View-Presenter.

An AppController handles things like event bus utilization, page choreography (via History and ValueChangeHandler), creation of Presenters, and delegation of services.

In the value change handling of the app controller page display is controlled. Here new Presenter objects are created and activated.

Presenters hold and manage the Views (which may also be created at the time the Presenter is created).