public function setEmail($email, $defaultEmail = null)
    {
        if (!empty($email)) {
            $this->email = $email;
        } else if (!empty($defaultEmail)) {
            $this->email = $defaultEmail;
            if (substr($this->email, 0, 1) == '@') {
                $this->email = $this->getId() . $this->email;
            }
        } else {
            $this->email = '';
        }
    }