public static function getComponentClassByParentClass($class)
    {
        $ret = self::getComponentClassesByParentClass($class);
        if (count($ret) != 1) {
            if (!$ret) {
                throw new Kwf_Exception("No Component with class '$class' found");
            }
            throw new Kwf_Exception("More then one component with class '$class' found, there should exist only one");
        }
        return $ret[0];
    }