If the customer is signed in, the application recalls these details and the forms are returned filled in. Finally the customer confirms the order and the application accepts the order for delivery. A receipt including a unique order number and other order details is presented to the customer. The application validates credit card and other information, updates its inventory database, and optionally sends a confirmation message via email. This is a fairly typical shopping scenario.
Some variations are possible, especially in the way the catalog is presented to the customer.
For instance, the application could provide specialized lists of items such as best-sellers, or discounts on certain items. There may also be variations in order processing, such as reducing the steps for making an order when the customer is already signed in. The application developer needs to design the application to support these variations, as well as others that might arise as the application evolves. Although this scenario presents the application from a single customer's point of view, the pet store application needs to simultaneously support a large number of shoppers. The pet store application does most of the administrative work of managing orders, creating new accounts, and other details without manual intervention.