/**
   * Receive notification of the start of an element.
   *
   * @param handler non-null reference to current StylesheetHandler that is constructing the
   *     Templates.
   * @param uri The Namespace URI, or an empty string.
   * @param localName The local name (without prefix), or empty string if not namespace processing.
   * @param rawName The qualified name (with prefix).
   * @param attributes The specified or defaulted attributes.
   */
  public void startElement(
      StylesheetHandler handler,
      String uri,
      String localName,
      String rawName,
      Attributes attributes)
      throws org.xml.sax.SAXException {

    try {
      ElemTemplateElement p = handler.getElemTemplateElement();
      boolean excludeXSLDecl = false;
      boolean isLREAsStyleSheet = false;

      if (null == p) {

        // Literal Result Template as stylesheet.
        XSLTElementProcessor lreProcessor = handler.popProcessor();
        XSLTElementProcessor stylesheetProcessor =
            handler.getProcessorFor(Constants.S_XSLNAMESPACEURL, "stylesheet", "xsl:stylesheet");

        handler.pushProcessor(lreProcessor);

        Stylesheet stylesheet;
        try {
          stylesheet = getStylesheetRoot(handler);
        } catch (TransformerConfigurationException tfe) {
          throw new TransformerException(tfe);
        }

        // stylesheet.setDOMBackPointer(handler.getOriginatingNode());
        // ***** Note that we're assigning an empty locator. Is this necessary?
        SAXSourceLocator slocator = new SAXSourceLocator();
        Locator locator = handler.getLocator();
        if (null != locator) {
          slocator.setLineNumber(locator.getLineNumber());
          slocator.setColumnNumber(locator.getColumnNumber());
          slocator.setPublicId(locator.getPublicId());
          slocator.setSystemId(locator.getSystemId());
        }
        stylesheet.setLocaterInfo(slocator);
        stylesheet.setPrefixes(handler.getNamespaceSupport());
        handler.pushStylesheet(stylesheet);

        isLREAsStyleSheet = true;

        AttributesImpl stylesheetAttrs = new AttributesImpl();
        AttributesImpl lreAttrs = new AttributesImpl();
        int n = attributes.getLength();

        for (int i = 0; i < n; i++) {
          String attrLocalName = attributes.getLocalName(i);
          String attrUri = attributes.getURI(i);
          String value = attributes.getValue(i);

          if ((null != attrUri) && attrUri.equals(Constants.S_XSLNAMESPACEURL)) {
            stylesheetAttrs.addAttribute(
                null, attrLocalName, attrLocalName, attributes.getType(i), attributes.getValue(i));
          } else if ((attrLocalName.startsWith("xmlns:") || attrLocalName.equals("xmlns"))
              && value.equals(Constants.S_XSLNAMESPACEURL)) {

            // ignore
          } else {
            lreAttrs.addAttribute(
                attrUri,
                attrLocalName,
                attributes.getQName(i),
                attributes.getType(i),
                attributes.getValue(i));
          }
        }

        attributes = lreAttrs;

        // Set properties from the attributes, but don't throw
        // an error if there is an attribute defined that is not
        // allowed on a stylesheet.
        try {
          stylesheetProcessor.setPropertiesFromAttributes(
              handler, "stylesheet", stylesheetAttrs, stylesheet);
        } catch (Exception e) {
          // This is pretty ugly, but it will have to do for now.
          // This is just trying to append some text specifying that
          // this error came from a missing or invalid XSLT namespace
          // declaration.
          // If someone comes up with a better solution, please feel
          // free to contribute it. -mm

          if (stylesheet.getDeclaredPrefixes() == null || !declaredXSLNS(stylesheet)) {
            throw new org.xml.sax.SAXException(
                XSLMessages.createWarning(XSLTErrorResources.WG_OLD_XSLT_NS, null));
          } else {
            throw new org.xml.sax.SAXException(e);
          }
        }
        handler.pushElemTemplateElement(stylesheet);

        ElemTemplate template = new ElemTemplate();
        if (slocator != null) template.setLocaterInfo(slocator);

        appendAndPush(handler, template);

        XPath rootMatch =
            new XPath(
                "/",
                stylesheet,
                stylesheet,
                XPath.MATCH,
                handler.getStylesheetProcessor().getErrorListener());

        template.setMatch(rootMatch);

        // template.setDOMBackPointer(handler.getOriginatingNode());
        stylesheet.setTemplate(template);

        p = handler.getElemTemplateElement();
        excludeXSLDecl = true;
      }

      XSLTElementDef def = getElemDef();
      Class classObject = def.getClassObject();
      boolean isExtension = false;
      boolean isComponentDecl = false;
      boolean isUnknownTopLevel = false;

      while (null != p) {

        // System.out.println("Checking: "+p);
        if (p instanceof ElemLiteralResult) {
          ElemLiteralResult parentElem = (ElemLiteralResult) p;

          isExtension = parentElem.containsExtensionElementURI(uri);
        } else if (p instanceof Stylesheet) {
          Stylesheet parentElem = (Stylesheet) p;

          isExtension = parentElem.containsExtensionElementURI(uri);

          if ((false == isExtension)
              && (null != uri)
              && (uri.equals(Constants.S_BUILTIN_EXTENSIONS_URL)
                  || uri.equals(Constants.S_BUILTIN_OLD_EXTENSIONS_URL))) {
            isComponentDecl = true;
          } else {
            isUnknownTopLevel = true;
          }
        }

        if (isExtension) break;

        p = p.getParentElem();
      }

      ElemTemplateElement elem = null;

      try {
        if (isExtension) {

          // System.out.println("Creating extension(1): "+uri);
          elem = new ElemExtensionCall();
        } else if (isComponentDecl) {
          elem = (ElemTemplateElement) classObject.newInstance();
        } else if (isUnknownTopLevel) {

          // TBD: Investigate, not sure about this.  -sb
          elem = (ElemTemplateElement) classObject.newInstance();
        } else {
          elem = (ElemTemplateElement) classObject.newInstance();
        }

        elem.setDOMBackPointer(handler.getOriginatingNode());
        elem.setLocaterInfo(handler.getLocator());
        elem.setPrefixes(handler.getNamespaceSupport(), excludeXSLDecl);

        if (elem instanceof ElemLiteralResult) {
          ((ElemLiteralResult) elem).setNamespace(uri);
          ((ElemLiteralResult) elem).setLocalName(localName);
          ((ElemLiteralResult) elem).setRawName(rawName);
          ((ElemLiteralResult) elem).setIsLiteralResultAsStylesheet(isLREAsStyleSheet);
        }
      } catch (InstantiationException ie) {
        handler.error(
            XSLTErrorResources.ER_FAILED_CREATING_ELEMLITRSLT,
            null,
            ie); // "Failed creating ElemLiteralResult instance!", ie);
      } catch (IllegalAccessException iae) {
        handler.error(
            XSLTErrorResources.ER_FAILED_CREATING_ELEMLITRSLT,
            null,
            iae); // "Failed creating ElemLiteralResult instance!", iae);
      }

      setPropertiesFromAttributes(handler, rawName, attributes, elem);

      // bit of a hack here...
      if (!isExtension && (elem instanceof ElemLiteralResult)) {
        isExtension = ((ElemLiteralResult) elem).containsExtensionElementURI(uri);

        if (isExtension) {

          // System.out.println("Creating extension(2): "+uri);
          elem = new ElemExtensionCall();

          elem.setLocaterInfo(handler.getLocator());
          elem.setPrefixes(handler.getNamespaceSupport());
          ((ElemLiteralResult) elem).setNamespace(uri);
          ((ElemLiteralResult) elem).setLocalName(localName);
          ((ElemLiteralResult) elem).setRawName(rawName);
          setPropertiesFromAttributes(handler, rawName, attributes, elem);
        }
      }

      appendAndPush(handler, elem);
    } catch (TransformerException te) {
      throw new org.xml.sax.SAXException(te);
    }
  }