private void appendHtmlPart(String text) {
    // flush previous white space if any
    if (whitespaceBuffer.length() > 0) {
      if (text != null) {
        whitespaceBuffer.append(text);
      }
      text = whitespaceBuffer.toString();
      clearBufferedWhiteSpace();
    }

    // de-dupe constants
    Integer constantNumber = constantsToNumbers.get(text);
    if (constantNumber == null) {
      constantNumber = constantCount++;
      constantsToNumbers.put(text, constantNumber);
      htmlParts.add(text);
    }
    htmlPartPrintlnToResponse(constantNumber);
  }