public function format()
    {
        switch ($this->displayFormat)
        {
            case self::FORMAT_CANADA:
                if (preg_match($this->displayFormat, $this->postalCode, $matches) && count($matches) === 3)
                {
                    return strtoupper(sprintf('%s %s', $matches[1], $matches[2]));
                }

                return $this->postalCode;

                break;
            case self::FORMAT_USA:
                return $this->postalCode;
                break;
            default:
                return $this->postalCode;
                break;
        }
    }