Use case analysis

Recap of requirement

• Requirement can be functional
  • Defines what the system should do
• requirements can be non-functional
  • Defies the trends are higher the functions are provided.

Use case and User stories

• User stories are less formal and simpler to define than use cases, This is widely used in agile Development.

• Use cases are a scenario based technique in the UML which identify the actors in an interaction, and which describe the interaction itself.

  • All possible interaction with the system should be involved in use cases
  • Sequence diagram may be used to add details to use cases by showing the sequence of event processing in the system.

Use case

• Actor
  • can be human can be non-human
• Use case: In a use case diagram, Use case is the task which the actor needs to perform with the help of system

The details of each use case should also be documented by a used case description

Include and extend

• Include
  • Always invoking
• Extend
  • Optional invoking

Note

• Use cases do not describe internal behaviors
• They must describe behaviors with external actors
• And always involve external behaviors