DOMConfigurator.java 文件源码

/**
    Used internally to parse the category factory element.
 */
 protected
 void parseCategoryFactory(Element factoryElement) {
   String className = subst(factoryElement.getAttribute(CLASS_ATTR));

   if(EMPTY_STR.equals(className)) {
     LogLog.error("Category Factory tag " + CLASS_ATTR + " attribute not found.");
     LogLog.debug("No Category Factory configured.");
   }
   else {
     LogLog.debug("Desired category factory: ["+className+']');
     Object factory = OptionConverter.instantiateByClassName(className,
                                                                LoggerFactory.class, 
                                                                null);
     if (factory instanceof LoggerFactory) {
         catFactory = (LoggerFactory) factory;
     } else {
         LogLog.error("Category Factory class " + className + " does not implement org.apache.log4j.LoggerFactory");
     }
     PropertySetter propSetter = new PropertySetter(factory);

     Element  currentElement = null;
     Node     currentNode    = null;
     NodeList children       = factoryElement.getChildNodes();
     final int length        = children.getLength();

     for (int loop=0; loop < length; loop++) {
       currentNode = children.item(loop);
if (currentNode.getNodeType() == Node.ELEMENT_NODE) {
  currentElement = (Element)currentNode;
  if (currentElement.getTagName().equals(PARAM_TAG)) {
    setParameter(currentElement, propSetter);
  } else {
          quietParseUnrecognizedElement(factory, currentElement, props);
     }
}
     }
   }
 }