@Override
 public Iterator<String> getAvailableAssemblyLineStatus(
     User user, AssemblyLine selectedAssemblyLine) throws NoClearanceException {
   if (user.canChangeOperationalStatus()) {
     return selectedAssemblyLine.getAllPossibleStates();
   } else {
     throw new NoClearanceException();
   }
 }
 @Override
 public String getCurrentAssemblyLineStatus(User user, AssemblyLine selectedAssemblyLine)
     throws NoClearanceException {
   if (user.canChangeOperationalStatus()) {
     return selectedAssemblyLine.currentState();
   } else {
     throw new NoClearanceException();
   }
 }