This package includes the GUI Flow control and Access control to select
a screen in a hierarchical menu.
Flow control
The GUIState interface define the methods to set up the states (screens) in a hierarchical menu.
This interface is implemented as an AbstractGUIState to create a template.
The DefaultGUIState implements all the methods.
Access Control
The access control is implemented on top of the flow control and defined in the RestrictedGUIState interface and implemented in the AbstractAdminState.
All the displays are derived from this class AbstractAdminState and created in the screen package.