code: public void startElement(
            String namespaceURI, String localName, String qName, Attributes atts)
              throws org.xml.sax.SAXException
    {
      throw new StopParseException();
    }
docs: The spec notes that "The xml-stylesheet processing instruction is allowed only in the prolog of an XML document.",
  so, at least for right now, I'm going to go ahead an throw a TransformerException
  in order to stop the parse.
  
  @param namespaceURI The Namespace URI, or an empty string.
  @param localName The local name (without prefix), or empty string if not namespace processing.
  @param qName The qualified name (with prefix).
  @param atts  The specified or defaulted attributes.
  
  @throws StopParseException since there can be no valid xml-stylesheet processing
  instructions past the first element.