private static function updateIdxContentContents(array $contents_saved, array $contents_removed)
    {
        if (null === self::$_application->getSite()) {
            return;
        }

        self::$em->getRepository('BackBee\ClassContent\Indexes\IdxContentContent')
                ->replaceIdxContentContents(array_diff($contents_saved, self::$_content_content_done))
                ->removeIdxContentContents($contents_removed);

        self::$_content_content_done = array_merge(self::$_content_content_done, $contents_saved);
    }