code: private void addToken(final List<String> list, String tok) {
          if (StringUtils.isEmpty(tok)) {
              if (isIgnoreEmptyTokens()) {
                  return;
              }
              if (isEmptyTokenAsNull()) {
                  tok = null;
              }
          }
          list.add(tok);
      }
docs: Adds a token to a list, paying attention to the parameters we've set.
  
  @param list  the list to add to
  @param tok  the token to add