public function getDefinitions()
    {
        $cache   = Cache::getEagerCache();
        $cacheId = 'SearchEngine-' . self::OPTION_STORAGE_NAME;

        if ($cache->contains($cacheId)) {
            $list = $cache->fetch($cacheId);
        } else {
            $list = $this->loadDefinitions();
            $cache->save($cacheId, $list);
        }

        return $list;
    }