public function getFilters($sql)
    {
        $classes    = array();
        $filterRows = $this->db->fetchAll($sql);
        $output     = array();

        // \MUtil_Echo::track($filterRows);
        foreach ($filterRows as $key => $filter) {
            $className = $filter['gaf_class'];
            if (! isset($classes[$className])) {
                $classes[$className] = $this->newFilterObject($className);
            }
            $filterObject = clone $classes[$className];
            if ($filterObject instanceof AppointmentFilterInterface) {
                $filterObject->exchangeArray($filter);
                $output[$key] = $filterObject;
            }
        }
        // \MUtil_Echo::track(count($filterRows), count($output));

        return $output;
    }