Assign the responsibility for receiving or handling a system event message to a class representing one of the following choices:
Represents the overall system, device, or subsystem (facade controller).
Represents a use case scenario within which the system event occurs, often named <UseCaseName>Handler, <UseCaseName>Coordinator, or <UseCaseName>Session (use-case or session controller).
Use the same controller class for all system events in the same use case scenario.
Corollary: Note that “window,” “applet,” “widget,” “view,” and “document” classes are not ...