Another Use Case example

In this example we look at a customer ordering a drink at a bar.  The bar staff must swipe an access card into the system before they put any transactions through the till.  So in this example, both the customer and the bar staff have to enter information into the system.  Both actors are needed to fulfil the use case “Buy a drink”, but the Customer is the primary actor (they trigger the use case and make the request for the service) and the Bar Staff is a secondary actor (the system requires information from them in order to complete).