private function load($type)
    {
        $index = $this->$type;
        if ($index) {
            return;
        }

        $cache = $this->di->get("cache");
        $key = $cache->createKey(__CLASS__, $type);
        $index = $cache->get($key);

        if (is_null($index) || $this->ignoreCache) {
            $createMethod = "create$type";
            $index = $this->$createMethod();
            $cache->put($key, $index);
        }

        $this->$type = $index;
    }