class Data
{
    public function __construct($db, $storage)
    {
        $this->db = $db;
        $this->cache = new Cache($storage, ...);
    }

    public function getSometing($user)
    {
        if (!$data = $this->cache->load($key)) {
            $db = $this->db;
            $data = $this->cache->save($key, function() use ($db, $user) {
                return $db->query(...);

            }, array(
                Cache::TAGS => array(...),
                ...
            ))
        }

        return $data;
    }

}


$data = new Data($db, $storage);
$this->template->results = $data->getSometing($user);