public function setDayOfWeek($dayOfWeek)
    {
        if (!preg_match(self::$_regex['dayOfWeek'], $dayOfWeek)) {
            throw new \InvalidArgumentException(sprintf('DayOfWeek "%s" is incorect', $dayOfWeek));
        }

        $this->dayOfWeek = $dayOfWeek;

        return $this->generateHash();
    }