protected function checkFilterParams($givenParams, $validParams, $requiredParams = array())
    {
        $filteredParams = array();
        foreach ($givenParams as $name => $value) {
            if (in_array(strtolower($name), $validParams)) {
                $filteredParams[ strtolower($name) ] = $value;
            } else {
                return false;
            }
        }
        foreach ($requiredParams as $name) {
            if (!array_key_exists(strtolower($name), $filteredParams)) {
                return false;
            }
        }

        return $filteredParams;
    }