public function setOrderid($orderid)
{
if (strlen($orderid) > 30) {
throw new InvalidArgumentException("Orderid cannot be longer than 30 characters");
}
if (preg_match('/[^a-zA-Z0-9_-]/', $orderid)) {
throw new InvalidArgumentException("Order id cannot contain special characters");
}
$this->parameters['orderid'] = $orderid;
}