public void addFunctionParameter(final String param) {
    if (param == null || param.isEmpty()) {
      throw new IllegalArgumentException("Parameter cannot be null or empty");
    }
    if (func_params == null) {
      func_params = Lists.newArrayList();
    }
    func_params.add(param);
  }
public void addFunctionParameter ( final String param ) { if ( param == null || param . isEmpty ( ) ) { throw new IllegalArgumentException ( "Parameter cannot be null or empty" ) ; } if ( func_params == null ) { func_params = Lists . newArrayList ( ) ; } func_params . add ( param ) ; }
Adds parameters for the root expression only.
@param param The parameter to add, cannot be null or empty
@throws IllegalArgumentException if the parameter is null or empty