public static function add(LoggerAppender $appender) {
		$name = $appender->getName();
		
		if(empty($name)) {
			trigger_error('log4php: Cannot add unnamed appender to pool.', E_USER_WARNING);
			return;
		}
		
		if (isset(self::$appenders[$name])) {
			trigger_error("log4php: Appender [$name] already exists in pool. Overwriting existing appender.", E_USER_WARNING);
		}
		
		self::$appenders[$name] = $appender;
	}