1. Jan 2002 91.3913R McFadyen1 Use Cases Widely used. Not just an OO technique. Diagramming defined in UML Each Use Case will meet one or more user goals; collectively, Use Cases represent the functionality required by a system. 2 Forms: diagrams, textual – simplicity is important, both used Scenario: an instance of a Use Case. Scenarios document a single flow (a story) through a Use Case, and are useful for testing purposes later on. Main success scenario, Alternate scenario 1, Alternate scenario 2, …

2. Jan 2002 91.3913R McFadyen2 Use Cases Introduced by Ivar Jacobson in 1986 literal translation from Swedish ”usage case” www.usecases.org - may be of use to you in the future “blackbox” style is recommended - specify what the system must do, and not how it must do it. A project may begin with the definition of many “brief” or “casual” use case definitions. Later on, these can be become “fully dressed”

3. Jan 2002 91.3913R McFadyen3 Use Cases Ch 6. Use Case example is very lengthy and fairly complete must read: pages 45-61, and sections 6.12, 6.13, 6.15 Ch 25. Use Case has been broken down into multiple Use Cases that are related via > and > must read: sections 25.1, 25.2, 25.3, 25.5

4. Jan 2002 91.3913R McFadyen4 Use Cases Diagrams System boundary Actors – ‘stick people’ Use cases – ovals Associations Actors and use cases Extend Include …

5. Jan 2002 91.3913R McFadyen5 Use Case Example - diagram Cashier Process Sale Handle Cheque Payment > Handle Cash Payment > Handle Credit Payment Process Rental >

6. Jan 2002 91.3913R McFadyen6 Cashier Process Sale Handle Cheque Payment > Handle Cash Payment > Handle Credit Payment Process Rental > Handle Gift Certificate Payment > Use Case Example - diagram

7. Jan 2002 91.3913R McFadyen7 Use Case Example - textual Ch 6 example. Process Sale Ch 25 example Process Sale Process Rental Handle Credit Payment Handle Cheque Payment Handle Gift Certificate Payment