/**
    Close all attached appenders implementing the AppenderAttachable
    interface.
    @since 1.0
 */
 synchronized
 void closeNestedAppenders() {
   Enumeration enumeration = this.getAllAppenders();
   if(enumeration != null) {
     while(enumeration.hasMoreElements()) {
Appender a = (Appender) enumeration.nextElement();
if(a instanceof AppenderAttachable) {
  a.close();
}
     }
   }
 }
 

/**
    Used internally to parse an appender element.
  */
 protected
 Appender parseAppender (Element appenderElement) {
   String className = subst(appenderElement.getAttribute(CLASS_ATTR));
   LogLog.debug("Class name: [" + className+']');    
   try {
     Object instance 	= Loader.loadClass(className).newInstance();
     Appender appender	= (Appender)instance;
     PropertySetter propSetter = new PropertySetter(appender);

     appender.setName(subst(appenderElement.getAttribute(NAME_ATTR)));
     
     NodeList children	= appenderElement.getChildNodes();
     final int length 	= children.getLength();

     for (int loop = 0; loop < length; loop++) {
Node currentNode = children.item(loop);

/* We're only interested in Elements */
if (currentNode.getNodeType() == Node.ELEMENT_NODE) {
  Element currentElement = (Element)currentNode;

  // Parse appender parameters 
  if (currentElement.getTagName().equals(PARAM_TAG)) {
           setParameter(currentElement, propSetter);
  }
  // Set appender layout
  else if (currentElement.getTagName().equals(LAYOUT_TAG)) {
    appender.setLayout(parseLayout(currentElement));
  }
  // Add filters
  else if (currentElement.getTagName().equals(FILTER_TAG)) {
    parseFilters(currentElement, appender);
  }
  else if (currentElement.getTagName().equals(ERROR_HANDLER_TAG)) {
    parseErrorHandler(currentElement, appender);
  }
  else if (currentElement.getTagName().equals(APPENDER_REF_TAG)) {
    String refName = subst(currentElement.getAttribute(REF_ATTR));
    if(appender instanceof AppenderAttachable) {
      AppenderAttachable aa = (AppenderAttachable) appender;
      LogLog.debug("Attaching appender named ["+ refName+
		   "] to appender named ["+ appender.getName()+"].");
      aa.addAppender(findAppenderByReference(currentElement));
    } else {
      LogLog.error("Requesting attachment of appender named ["+
		   refName+ "] to appender named ["+ appender.getName()+
               "] which does not implement org.apache.log4j.spi.AppenderAttachable.");
    }
  } else {
         parseUnrecognizedElement(instance, currentElement, props);
     }
}
     }
     propSetter.activate();
     return appender;
   }
   /* Yes, it's ugly.  But all of these exceptions point to the same
      problem: we can't create an Appender */
   catch (Exception oops) {
     LogLog.error("Could not create an Appender. Reported error follows.",
	   oops);
     return null;
   }
 }