Ordering process activity diagram

[Миљан Ушћумлић <miljan.miljan@gmail.com>]

Hi all,

I am pretty new to the UBL and e-invoicing world in general and I am kindly asking for a help in understanding of Ordering process business flow depicted on the page 51 of the UBL-2.2.pdf specification.
My main confusion is mainly in regard with a Seller Party's swim lane of this activity diagram.

My questions are:

1. For activity flow: Place Order -> Receive Order -> process order -> Add Detail there are no guards on outgoing activity edges of the "Add Detail" activity. So, when is appropriate to go in one direction sending Order Response, and when to go in the other by invoking "Accept Order" activity? As I understood it, when the Order is modified Order Response (in which the change is reflected) have to be sent to the Buyer Party.? Activity edges are mutually exclusive so going to "Accept Order" activity instead, we are in the position to send only Order Response Simple (which does not contain any Order amendments).

2. For activity flow:  Place Order -> Receive Order -> process order -> Accept Order what would be an example when the guard [response required] is true, and what [response is not required]?
Does it mean that response is always required when the Order is accepted so the Buyer Party MUST be notified of that acceptance of the Order enabling the activity flow to end in the "order accepted" final node?
And, I am puzzled that after "Accept Order" activity (when the order is accepted by the Seller Party?) following the edge guarded with [response not required], the flow ends in the "order canceled" final node. I am reading this as a situation when the Order has been accepted but still afterwards cancelled solely by the Seller Party not notifying Buyer Party about it at all. And I am certain that I am badly missing something here.

Any help and guidance to better understand Ordering process is highly appreciated.

Regards,
Miljan
Belgrade, Serbia

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