code: public String getIndependentParentLink(String style)
  			throws ParserConfigurationException, IOException, SAXException {
  		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
  		DocumentBuilder builder = factory.newDocumentBuilder();
  		InputSource src = new InputSource(new StringReader(style));
  		Document doc = builder.parse(src);
  		NodeList links = doc.getElementsByTagName("link");
  		for (int i = 0; i < links.getLength(); ++i) {
  			Node n = links.item(i);
  			Node relAttr = n.getAttributes().getNamedItem("rel");
  			if (relAttr != null) {
  				if ("independent-parent".equals(relAttr.getTextContent())) {
  					Node hrefAttr = n.getAttributes().getNamedItem("href");
  					if (hrefAttr != null) {
  						return hrefAttr.getTextContent();
  					}
  				}
  			}
  		}
  		return null;
  	}
docs: Parse a string representing a dependent parent style and
  get link to its independent parent style
  @param style the dependent style
  @return the link to the parent style or <code>null</code> if the link
  could not be found
  @throws ParserConfigurationException if the XML parser could not be created
  @throws IOException if the string could not be read
  @throws SAXException if the string could not be parsed