public void checkCanBuildList(){
  if (listeners.isEmpty()) {
    if (sysNameList != null) {
      deregister();
      sysNameList=null;
    }
    canBuildList=true;
  }
}

public void checkCanBuildList ( ) { if ( listeners . isEmpty ( ) ) { if ( sysNameList != null ) { deregister ( ) ; sysNameList = null ; } canBuildList = true ; } }
if no listeners , clear sysnamelist pointer and allow list to be re - built * manager can implement specifics in deregister ( ) .
