code: @Override
      public void setConfiguration(
                      final Properties config
                      )
      throws ValidityException
      {
          String  pattern = config.getProperty( "pattern" );
          if (pattern == null) {
              throw new ValidityException( "no 'pattern' parameter" );
          }
  
          try {
              _formatter = new SimpleDateFormat( pattern );
                           //throws IllegalArgumentException
          } catch (Exception ex) {
              throw new ValidityException( "invalid 'pattern' parameter: "
                              + ex.getMessage() );
          }
      }
docs: **************************************************************