code: public void ENsaveinpfile( String fileName ) throws EpanetException {
          int err = epanet.ENsaveinpfile(fileName);
          checkError(err);
      }
docs: Writes all current network input data to
  a file using the format of an EPANET input file.
  
  @param fileName name of the file where data is saved.
  @throws EpanetException