1. 1 Use Cases 1 CSSE 371 Software Requirements and Specification Mark Ardis, Rose-Hulman Institute September 17, 2004

2. 2 What is a Use Case?  Sequences of actions  Performed by system of interest  Observable result of value to a particular actor

3. 3 Use Case Method 1. Identify the actors 2. Identify the use cases 3. Identify actor/use case relationships 4. Outline use cases 5. Refine use cases

4. 4 1. Identify the Actors  Who uses the system?  Who gets/provides information from/to system?  Who supports the system?  What other systems interact with this system?

5. 5 2. Identify the Use Cases  What are the intentions of each actor with respect to the system?  Give a descriptive name: Start with an action verb Describes goal or intent  Give a one-sentence description

6. 6 3. Identify Actor/Use Case Relationships  Draw a diagram showing relationships between actors and use cases Eat foodBuy food Parent Child

7. 7 4. Outline Use Cases  Describe sequence of events in basic flow (sunny day scenario)  Describe sequences of events in alternate flows (rainy day scenarios)

8. 8 5. Refine Use Cases (more later)