/**
* String representation of object
*
* @link http://php.net/manual/en/serializable.serialize.php
* @return string the string representation of the object or <b>null</b>
*/
public function serialize()
{
// Force to serialize the group & the role objects too
$this->getGroup();
$this->getRoleId();
$this->getResourceId();
return parent::serialize();
}
