public function read($key = null)
    {
        try {
            $value = $this->subject->read($key);
        } catch (Doozr_Base_Service_Exception $exception) {
            throw new Doozr_Form_Service_Exception(
                sprintf('The key "%s" does not exist in store.', $key),
                null,
                $exception
            );
        }

        return $value;
    }