public function setTitle($title = '')
    {
        if ('' == $title) {
            $title = 'GrowlNotify';
        }

        if (!is_string($title)) {
            throw new BuildException(
                '"title" attribute is invalid.' .
                ' Expect to be a string, actual is ' . gettype($title)
            );
        }

        $this->title = $title;
    }