code: public static int optionLength(final String option) {
          // Any arguments used for the doclet need to be recognized here. Many javadoc plugins (ie. gradle)
          // automatically add some such as "-doctitle", "-windowtitle", which we ignore.
          if (option.equals(DOC_TITLE_OPTION) ||
              option.equals(WINDOW_TITLE_OPTION) ||
              option.equals(SETTINGS_DIR_OPTION) ||
              option.equals(DESTINATION_DIR_OPTION) ||
              option.equals(BUILD_TIMESTAMP_OPTION) ||
              option.equals(ABSOLUTE_VERSION_OPTION) ||
              option.equals(OUTPUT_FILE_EXTENSION_OPTION) ||
              option.equals(INDEX_FILE_EXTENSION_OPTION)) {
              return 2;
          } else if (option.equals(QUIET_OPTION) ||
                     option.equals(USE_DEFAULT_TEMPLATES_OPTION)) {
              return 1;
          } else {
              logger.error("The Javadoc command line option is not recognized by the Barclay doclet: " + option);
              return 0;
          }
      }
docs: Validates the given options against options supported by this doclet.
  
  <p>Custom Barclay doclets that want to have custom command line options should provide an
  implementation of this static method, and also override override {@link #parseOption}).
  Both methods should handle the custom options, delegating back to the base class methods
  defined here to allow default handling of builtin options.
  
  @param option Option to validate.
  @return Number of potential parameters; 0 if not supported.