code: public PatternTokenizer setExtraQuotingCharacters(UnicodeSet syntaxCharacters) {
          this.extraQuotingCharacters = (UnicodeSet) syntaxCharacters.clone();
          needingQuoteCharacters = null;
          return this;
      }
docs: Sets the extra characters to be quoted in literals
  @param syntaxCharacters Characters to be set as extra quoting characters.
  @return A PatternTokenizer object in which characters are specified as extra quoting characters.