Process Descriptions

Buyer – Seller Example

The process involves three participants, a Buyer, a Seller and a Delivery Service. First, the process starts when the buyer selects a product, and then he asks for a quote to the Seller. Later, the seller replies to the buyer with an offer.  The Buyer can either accept the offer, reject it, or ask again. If the Buyer accepts, the Seller sends an order to the Delivery Service, who will then send a detailed confirmation message directly to the Buyer

Additional constraints:

The seller will reply only once per request

The buyer can accept, ask, or reject only once per reply from the seller

An accepted offer is sent only once

If the buyer asks again, the seller is allowed to reply back 

A quote is eventually followed by a decision


Order Placement Example

Order Placement Example

An order can be finalized at most  once

Once an order is finalized, it can be either  confirmed or rejected

A confirmed order may be rejected later on (due to “late” problems), but not vice-versa: a reject cannot be reverted.

An order can be confirmed only if it shipped before. An order may be rejected autonomously by the seller.

However, if the warehouse notifies the seller of a shipment issue, then the seller has to reject the order.

The warehouse decision is firm: “Ship” and “Notify shipment issue” are mutually exclusive