Handler interface for {@link BeforeSelectionEvent} events.

@param <T> the type about to be selected

abstract class BeforeSelectionHandler<T> extends EventHandler {

 /**
  * Called when {@link BeforeSelectionEvent} is fired.
  *
  * @param event the {@link BeforeSelectionEvent} that was fired
  */
 void onBeforeSelection(BeforeSelectionEvent<T> event);
}