code: public static int optionLength(String option) {
      if (option.equals("-help")) {
        System.out.printf(USAGE);
        return 1;
      }
      if (option.equals("-i") || option.equals("-classdoc") || option.equals("-singledash")) {
        return 1;
      }
      if (option.equals("-docfile")
          || option.equals("-outfile")
          || option.equals("-format")
          || option.equals("-d")) {
        return 2;
      }
      return 0;
    }
docs: Given a command-line option of this doclet, returns the number of arguments you must specify on
  the command line for the given option. Returns 0 if the argument is not recognized. This method
  is automatically invoked by Javadoc.
  
  @param option the command-line option
  @return the number of command-line arguments needed when using the option
  @see <a
  href="https://docs.oracle.com/javase/8/docs/technotes/guides/javadoc/doclet/overview.html">Doclet
  overview</a>