public void removeDecorator(final OperatorDrawDecorator decorator){
  if (decorator == null) {
    throw new IllegalArgumentException("decorator must not be null!");
  }
  operatorDecorators.remove(decorator);
}

public void removeDecorator ( final OperatorDrawDecorator decorator ) { if ( decorator == null ) { throw new IllegalArgumentException ( "decorator must not be null!" ) ; } operatorDecorators . remove ( decorator ) ; }
removes the given operator decorator . if the decorator has already been removed , does nothing .
