code: public static String extractSubstring(String str, String open, String close)
      {
          return extractSubstring(str, open, close, DEFAULT_ESCAPECHAR, true);
      }
docs: Extracts and returns a substring of the given string starting from the
  given open sequence and finishing by the specified close sequence. This
  method unescapes all symbols prefixed by the given escape symbol.
  
  @param str from this string the substring framed by the specified open
  and close sequence will be returned
  @param open the start substring sequence
  @param close the closing substring sequence
  @return a substring of the given string starting from the given open
  sequence and finishing by the specified close sequence