protected function getObjectsRawData(array $parameters = array())
    {
        $cacheKey = md5(json_encode(array($this->getName(), $parameters)));

        if (!array_key_exists($cacheKey, self::$listObjectsCache)) {
            $tmp = array();

            foreach ($parameters as $k => $v) {
                if (in_array($k, self::$allowedParameters)) {
                    $tmp[$k] = $v;
                }
            }

            $response = $this->connection->makeRequest(Client::GET, array($this->name), array(), $tmp);
            self::$listObjectsCache[$cacheKey] = $response['body'];
        }

        return self::$listObjectsCache[$cacheKey];
    }