Use Case

What is it?

Template Diagram Model Description

Basic Definition

Of who can do what within a system?

  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)

Purpose of use case

 Users ◦ End user ◦ Other systems ◦ Hardware devices

Focus on the user end

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

Why Use Case?

End users Systems Analysts Use case

Who creates use case?

Systems engineers Software engineers

Who uses 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 http://en.wikipedia.org/wiki/Use_case#History

Requirements of use case

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

Applications of use case

  Diagram used in UML (unified modeling language) in software engineering http://en.wikipedia.org/wiki/Use_cas e_diagram

Use case diagram (in UML)

Use case name Version Goal Summary Actors Preconditions Triggers Basic course of events Alternative paths Post conditions Business rules Notes Author and date

Fill in descriptions Use case template

Sample template – see http://en.wikipedia.org/wiki/U se_case for what would go in each of fields in the right hand column of this template