// Ask the Screen for its Layout and then execute the Layout.
// The Screen can override the getLayout() method to re-define
// the Layout depending on data passed in via the
// data.parameters object.
ScreenLoader sl = ScreenLoader.getInstance();
Screen aScreen = sl.getInstance(data.getScreen());
String layout = aScreen.getLayout(data);
// If the Layout has been set to be null, attempt to execute
// the Screen that has been defined.
if ( layout != null )
{