code: private static final String escape(String str) {
          if (str == null) {
              return null;
          }
  
          StringBuilder sb = new StringBuilder(str.length() * 2);
          int len = str.length();
          for (int i = 0; i < len; i++) {
              char c = str.charAt(i);
              switch (c) {
                  case TOKEN_DELIM:
                  case USER_DATA_DELIM:
                  case USER_ATTRIB_DELIM:
                      sb.append('\\');
                      break;
                  default:
                      break;
              }
              sb.append(c);
          }
          return sb.toString();
      }
docs: /*
  Remove the delimination of the String form.
  
  @param str The String form