PropertyConfigurator.java 文件源码

Appender parseAppender(Properties props, String appenderName) {
   Appender appender = registryGet(appenderName);
   if((appender != null)) {
     LogLog.debug("Appender \"" + appenderName + "\" was already parsed.");
     return appender;
   }
   // Appender was not previously initialized.
   String prefix = APPENDER_PREFIX + appenderName;
   String layoutPrefix = prefix + ".layout";

   appender = (Appender) OptionConverter.instantiateByKey(props, prefix,
                      org.apache.log4j.Appender.class,
                      null);
   if(appender == null) {
     LogLog.error(
             "Could not instantiate appender named \"" + appenderName+"\".");
     return null;
   }
   appender.setName(appenderName);

   if(appender instanceof OptionHandler) {
     if(appender.requiresLayout()) {
Layout layout = (Layout) OptionConverter.instantiateByKey(props,
                              layoutPrefix,
                              Layout.class,
                              null);
if(layout != null) {
  appender.setLayout(layout);
  LogLog.debug("Parsing layout options for \"" + appenderName +"\".");
  //configureOptionHandler(layout, layoutPrefix + ".", props);
         PropertySetter.setProperties(layout, props, layoutPrefix + ".");
  LogLog.debug("End of parsing for \"" + appenderName +"\".");
}
     }
     final String errorHandlerPrefix = prefix + ".errorhandler";
     String errorHandlerClass = OptionConverter.findAndSubst(errorHandlerPrefix, props);
     if (errorHandlerClass != null) {
        ErrorHandler eh = (ErrorHandler) OptionConverter.instantiateByKey(props,
                  errorHandlerPrefix,
                  ErrorHandler.class,
                  null);
        if (eh != null) {
              appender.setErrorHandler(eh);
              LogLog.debug("Parsing errorhandler options for \"" + appenderName +"\".");
              parseErrorHandler(eh, errorHandlerPrefix, props, repository);
              final Properties edited = new Properties();
              final String[] keys = new String[] { 
                      errorHandlerPrefix + "." + ROOT_REF,
                      errorHandlerPrefix + "." + LOGGER_REF,
                      errorHandlerPrefix + "." + APPENDER_REF_TAG
              };
              for(Iterator iter = props.entrySet().iterator();iter.hasNext();) {
                  Map.Entry entry = (Map.Entry) iter.next();
                  int i = 0;
                  for(; i < keys.length; i++) {
                      if(keys[i].equals(entry.getKey())) break;
                  }
                  if (i == keys.length) {
                      edited.put(entry.getKey(), entry.getValue());
                  }
              }
              PropertySetter.setProperties(eh, edited, errorHandlerPrefix + ".");
              LogLog.debug("End of errorhandler parsing for \"" + appenderName +"\".");
        }

     }
     //configureOptionHandler((OptionHandler) appender, prefix + ".", props);
     PropertySetter.setProperties(appender, props, prefix + ".");
     LogLog.debug("Parsed \"" + appenderName +"\" options.");
   }
   parseAppenderFilters(props, appenderName, appender);
   registryPut(appender);
   return appender;
 }