public function getObject($className, $criteria= null, $cacheFlag= true) {
        $instance= null;
        $this->sanitizePKCriteria($className, $criteria);
        if ($criteria !== null) {
            $instance = $this->call($className, 'load', array(& $this, $className, $criteria, $cacheFlag));
        }
        return $instance;
    }