A use case
tells a story of reaching a goal. It is
a set of scenarios that describe both succeeding and failing.
UC 4: Clerk takes customer order
1. On order screen, clerk enters the customer information,
order items, and item quantities.
2. System checks customer credit,
credit OK.
3. System checks order quantities,
quantities OK.
4. System accepts and queues the order.
Extensions:
2a. Low credit: Clerk takes prepayment,
return to step 3.
3a. Low on stock: Customer accepts reduced order quantity,
return to step 4, or
Customer cancels order, terminate use case.