Chapter 13. Develop Instance Scenarios

What’s in this chapter?

This chapter discusses the concept of use case instances and their use in complementing the use case model. Example approaches discussed include one that is very informal and one that is formal.

We have seen that use cases provide an abstract view of the activities that occur between an actor and the system. When use cases model these activities, however, they do not describe how specific instances of the interactions will occur. Use case instances can be thought of as paper prototypes of how a use case will execute in a given situation. In this sense they can assist in drawing out and validating requirements from the stakeholders. Use case instances are another way of exploring the details, alternatives, and exceptions in the use cases. They are also a nice transition into acceptance and system test cases.