The theater is considering a change in its policy that all sales are fi nal. In particular, it is going to allow cancellations of a sale up to 24 hours after a sale is made. The customer requests a cancellation by submitting the Sale Transaction ID, name, and address on the cancellation page of the Web form. The system interrogates the database to confi rm the information and that the transaction is less than 24 hours old. If true, the system asks the customer to confi rm that he or she wants to cancel the sale. If the customer confi rms the cancellation, the MasterCard account is credited and the Status attribute of the Sale object is changed from Active to Canceled. The system confi rms to the customer that the sale has been canceled. Also, the Ticket object status changes from committed to available. The cancellation of a sale requires crediting the MasterCard (reversing the debit) and writing a cancellation to the Sale and Ticket objects. All tickets involved in the sale become uncommitted when the sale is canceled. (a) Write a text description of a normal scenario for the Cancel sale use case. (b) From the scenario, create a sequence diagram at the level of detail shown in Figure 9.6. (c) Create an activity diagram. Include other logical scenarios in the activity diagram. (d) Revise the ticket objects state chart diagram (Figure 9.11) to include the new use case. 400 Unifi ed Modeling Language (e) Create a new state chart showing the behavior of the Sale object. (f) Update the class diagram (Figure 9.21) to include the new attributes and methods required for this use case.

Unified Modeling Language 379 cactor> System AuthorizationObjects Customer Request performance and seating Veirfy available Offer seating Accept seating Hold ticket Request credit card information Credit card information Confirm sale OK Request authorization Authorization approved Debit credit card Charge accepted Lifeline Commit sale Final confirmation Figure 9.6 Sequence Hiagram of scenario 1