code: private List<String> getMatchingLongOptions(String token) {
          if (allowPartialMatching) {
              return options.getMatchingOptions(token);
          } else {
              List<String> matches = new ArrayList<>(1);
              if (options.hasLongOption(token)) {
                  Option option = options.getOption(token);
                  matches.add(option.getLongName());
              }
              return matches;
          }
      }
docs: Returns a list of matching option strings for the given token, depending
  on the selected partial matching policy.
  
  @param token the token (may contain leading dashes)
  @return the list of matching option strings or an empty list if no
  matching option could be found