protected static final String addEscapes(String str) {
    StringBuffer retval = new StringBuffer();
    char ch;
    for (int i = 0; i < str.length(); i++) {
      switch (str.charAt(i))
      {
        case 0 :
          continue;
        case '\b':
          retval.append("\\b");
          continue;
        case '\t':
          retval.append("\\t");
          continue;
        case '\n':
          retval.append("\\n");
          continue;
        case '\f':
          retval.append("\\f");
          continue;
        case '\r':
          retval.append("\\r");
          continue;
        case '\"':
          retval.append("\\\"");
          continue;
        case '\'':
          retval.append("\\\'");
          continue;
        case '\\':
          retval.append("\\\\");
          continue;
        default:
          if ((ch = str.charAt(i)) < 0x20 || ch > 0x7e) {
            String s = "0000" + Integer.toString(ch, 16);
            retval.append("\\u" + s.substring(s.length() - 4, s.length()));
          } else {
            retval.append(ch);
          }
          continue;
      }
    }
    return retval.toString();
  }