public Document HTMLGetConstraintQuery(String html, String url, String query, AlchemyAPI_ConstraintQueryParams params)
    throws IOException, XPathExpressionException,
           SAXException, ParserConfigurationException
	{
	    CheckHTML(html, url);
	    if (null == query || query.length() < 2)
	        throw new IllegalArgumentException("Invalid constraint query specified");

	    params.setUrl(url);
	    params.setHtml(html);
	    params.setCQuery(query);
	
	    return POST("HTMLGetConstraintQuery", "html", params);
	}