Interfaces which are related with JSF events are present in package'javax.faces.event'. All Events present in JSF shall be extending the javax.faces.event.FacesEvent. This class’s constructor has argument UIComponent that would be making it specific that this Event is for which UI component.
UIComponent someComponent = new UIComponent();
MyFacesEvent event = new MyFacesEvent(someComponent);
UIComponent sourceCompoenent = event.getComponent();