Jan R 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, …

Jan R McFadyen2 Use Cases Introduced by Ivar Jacobson in 1986 literal translation from Swedish ”usage case” - 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”

Jan R 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

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

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

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

Jan R 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