1. 2.3 Examples: Ski resort information system
Users should be able to query weather and snow condition forecasts for a date they enter.
The system should allow to book single or double rooms at the resort hotel “Skier’s Luck” online (with credit card).
Visitors should be able to book one-day beginners courses on snowboards.
There is only one course a day.
The max. size of a course is 8 persons.
The resort offers special courses for kids. In order to built courses with kids of same age, the customer has to enter the kid’s age.
Canceling of course or room bookings are only possible up to 10 days ahead.
CPSC 333: Foundations of Software Engineering J. Denzinger

2. CPSC 333: Foundations of Software Engineering J. Denzinger

3. Errors you should prevent (1)!
<< includes >> stereotype in actor associations
CPSC 333: Foundations of Software Engineering J. Denzinger

4. Errors you should prevent (2)!
Associations between actors
Unnamed associations between use cases
CPSC 333: Foundations of Software Engineering J. Denzinger

5. Errors you should prevent (3)!
System no use case!
Name relations!
CPSC 333: Foundations of Software Engineering J. Denzinger

6. Errors you should prevent (4)!
Wrong understanding of the <<extends>> stereotype
CPSC 333: Foundations of Software Engineering J. Denzinger

7. Errors you should prevent (5)!
Diagram moves main functionality outside the system
CPSC 333: Foundations of Software Engineering J. Denzinger

8. Errors you should prevent (6)!
Data structures instead of functions as use cases, e.g. date, age, database
relations not named
CPSC 333: Foundations of Software Engineering J. Denzinger

9. Example Use Case Diagram
Query weather&snow forecast
<<include>>
Book room
Enter personal info
Visitor
Book SB course
<<include>>
<<extend>> (Enter kid’s age)
Cancel course
Book kids’ SB course
Cancel room
CPSC 333: Foundations of Software Engineering J. Denzinger

10. Use Case (1) Use Case: Query weather&snow forecast Precond: -
Main flow:
Visitor enters date
Weather & snow forecast for local region is displayed for specified date
CPSC 333: Foundations of Software Engineering J. Denzinger

11. Use Case (2) Use Case: Book SB course Precond: - Main flow:
Visitor enters date
Include (Enter personal info)
(Enter kid’s age)
Store reservation
Confirm reservation to Visitor
Exceptional flow:
If number of course participants for specified date > 8, then tell visitor so and let him choose another date
CPSC 333: Foundations of Software Engineering J. Denzinger

12. Use Case (3) Use Case: Book kids’ SB course
Precond: SB course is for a kid
Main flow:
Enter kid’s age
Store reservation
Confirm reservation to Visitor
Exceptional flow:
If course for specified date is adult course, then tell visitor so and let him choose another date.
If course for specified date is kids’ course, and the specified age is outside the course’s age range, then tell visitor so and let him choose another date.
CPSC 333: Foundations of Software Engineering J. Denzinger

13. Example: literature reference management system
Storage and retrieval of references, e.g.
Title: The unified modeling language user guide
Authors: G. Booch, J. Rumbaugh, I Jacobson
Publisher: Addison Wesley
Publication year: 1998
Small exercise:
Draw a Use Case Diagram (at least two use cases)
Describe use cases (at least one)
Title: Software engineering in the Internet age
Authors: F. Maurer, G. Kaiser
Publisher: IEEE
Publication year: 1998
Journal: IEEE Internet Computing Magazine
Volume: 2
Issue: 5
CPSC 333: Foundations of Software Engineering J. Denzinger

14. Use Case Diagram: literature reference management
Add reference
Remove reference
User
Search for reference
List references
CPSC 333: Foundations of Software Engineering J. Denzinger

15. Event flow: List references
Precondition: user has selected “list references” functionality.
The system prompts the user to select the device: printer or file.
The system prompts the user to select the print order: by name or by title.
The use case finishes with the system printing the list on the requested device.
CPSC 333: Foundations of Software Engineering J. Denzinger

16. Event flow: Add reference
Precondition: user has selected “add new reference” functionality.
The system prompts the user to select if he/she wants to add a normal reference or a book.
The system prompts the user to enter title, author, and publisher of the reference (Add journal paper) (Except-1).
The user is notified that the reference has been successfully added.
Except-1: The reference already exists. The user can re-enter the data or terminate the use case.
CPSC 333: Foundations of Software Engineering J. Denzinger

17. Use case: Add journal paper
Add journal paper: If the paper is a journal, then the system additionally asks for the journal’s name, the volume number and the issue number.
Add reference
<<extend>>
Add journal
paper
CPSC 333: Foundations of Software Engineering J. Denzinger

18. Exercises
Develop use case diagram and textual use case descriptions for:
an elevator (1 elevator, n floors)
a telephone (with number memory)
an system
CPSC 333: Foundations of Software Engineering J. Denzinger

19. enter and exit through a door
Elevator -- Use Case
1 elevator, n floors
press an elevator button
press a floor button
User
Elevator
enter and exit through a door
CPSC 333: Foundations of Software Engineering J. Denzinger

20. Small Test: Bank account manager
System has to run on an automated teller machine.
User must be able to deposit checks into the account.
User must be able to draw money from the account.
User should be able to query the balance of his/her account.
The user should get a receipt for a transaction on request. The transaction type (withdrawal or deposit), the transaction date, the account number, the amount, and the new balance should be visible on the receipt.
After each transaction the new balance should be displayed to the user.
CPSC 333: Foundations of Software Engineering J. Denzinger

21. Example: bank account manager
Use case for withdrawal
Use case for depositing
Use case for balance query
Small Test:
Draw a Use Case Diagram (Organize use cases)
Describe use cases
“include”-relationship:
Use case for entering the pin number and comparing the pin number on the card with the entered pin number
Use case for printing the receipt
CPSC 333: Foundations of Software Engineering J. Denzinger