Use Case What is it?

Basic Definition Of who can do what within a system? TemplateDiagramModelDescription

Purpose of use case Describe system from user’s point of view ◦Describe interaction between user and system Indicate system response to request/trigger originating outside the system (by user) ◦Provide sequence of steps involved in interaction ◦Depicts functional requirements of the system for a task (how task/goal achieved)

Focus on the user end Users ◦End user ◦Other systems ◦Hardware devices

Why Use Case? Use User focus Case Complete series of events Complete series of events for one particular use of a system Use case simplified from usage scenarios/usage case

Who creates use case? End users Systems Analysts Use case

Who uses use case? Systems engineersSoftware engineers

Requirements of use case Use case should: ◦Describe what the system shall do for the actor to achieve a particular goal. ◦Include no implementation-specific language. ◦Be at the appropriate level of detail. ◦Not include detail regarding user interfaces and screens. This is done in user-interface design. From

Applications of use case Systems design Programming Object-oriented design UML (unified modeling language) Wherever functional requirements need to be captured Business use Software use

Use case diagram (in UML) Diagram used in UML (unified modeling language) in software engineering e_diagram e_diagram

Use case template Sample template – see se_case for what would go in each of fields in the right hand column of this template se_case Fill in descriptions Use case name Version Goal Summary Actors Preconditions Triggers Basic course of events Alternative paths Post conditions Business rules Notes Author and date