Create a model of a Use Case to show the relationships between actors and packages.
During business analysis of the system, you can develop one Use Case diagram that acts as the context Use Case diagram. On this diagram, you can draw the overall Use Cases of the domain, with actor interactions. One of the goals of drawing a Context Use Case diagram is to identify all of the actors of the system. The Use Cases on the diagram you create are analogous to the Process Threads you established in the previous section on Business Modeling.
Create a Use Case diagram
1 In the UML tab of the browser, right-click the package Reservations > New.
2 Under Diagrams, double-click Use Case. The New Diagram dialog opens.
3 Type the new Use Case diagram "Reservations Context Diagram". Click OK. In the next dialog that opens (titled Diagram - Use Case - Reservations Context Diagram), you can specify the package that this diagram is contained in. It is automatically filled in with the name of the package you right-clicked (Reservations). You can specify a different package at this point.
Modeling an Actor
When modeling scenarios, determine how an external actor uses the system and what they gain from it. Also, determine all the possible scenarios of the actor. In the hotel system, when making a reservation, it is an external actor called Customer.
1 From the Draw toolbar, select Actor. The pointer turns into a drawing pen.
2 Click one time on the diagram workspace to draw the actor. Name the actor Customer, and press Enter.
Modeling a Use Case
The Customer can make a reservation. Draw a Use Case called Make Reservation.
1 Select the Use Case symbol on the toolbar (looks like an oval). The pointer turns into a drawing pencil and draw it on the diagram. Name the Use Case Make Reservation.
During Use Case analysis, the Use Case Association line is used to show simple communication between an actor and a Use Case.
2 From the toolbar, select the Use Case Association line drawing too. the pointer turns into a drawing pencil.
3 Draw an association between the Customer actor and the Make Reservation Use Case. To draw this association:
•In the Customer actor, click one time to get a + connector indicator.
•Move your line over to the Make Reservation Use Case to get a + connector indicator.
•When you get a + indicator at both ends of the Use Case Association line, click your mouse again to make the connection.
Note You can adjust the size of your Use Case after you have drawn it. To change the default size, select the Use Case and choose Format > Symbol Format > Symbol Style. In Symbol Style dialog, select Set Size and click OK.
4 From the Draw toolbar, select Actor. Place the actor on the diagram to the right of the Make Reservation Use Case, name it Reception, and press Enter.
5 From the toolbar, select the Use Case Association line drawing tool and draw a Use Case Association line from the actor Reception to the Use Case Make Reservation.
Model multiple scenarios
A customer also interacts with our reservation by confirming a reservation, canceling a reservation, and reserving a conference room. In addition, reception can check in a guest or check out a guest. Model these scenarios as Use Cases:
1 Draw the following Use Cases, under Make Reservation:
•Confirm Reservation
•Cancel Reservation
•Check In Guest
•Check Out Guest
•Reserve Conference Room
2 Connect the Customer actor to each Use Case with a Use Case Association line, and connect the Reception actor to each Use Case with a Use Case Association line to create the diagram below:
