Software Engineering Quiz

Use Case Descriptions

• Use case descriptions consist of interactions among a product and an actor.
• A use case description includes the use case name and number, actors, and stakeholders and needs.

Preconditions and Postconditions

• A precondition is an assertion guaranteed to be true before the activity or operation begins.
• A postcondition is an assertion guaranteed to be true when the activity or operation finishes.

Triggers

• A trigger is an event that causes a use case to begin.

Use Case Description Format

• Underline text refers to another use case.
• Extensions section uses complicated numbering scheme.
• Indentation is used to make extensions easier to read.

Methods of Writing Use Case Descriptions

• Actors in a use case are almost always stakeholders.
• Preconditions must be true before the statement begins.
• Need list should be reviewed when writing each use case.

Extensions

• Once the basic flow is defined, the extensions can be specified.
• The alternatives are called extensions as they extend the activity flow in a different direction from a branch point.

Use Case Description Heuristics

• Fill in the use case template from top to bottom.
• Write simple declarative sentences in active voice.
• Avoid sequence of steps by the actors and product.

Alternative Use Cases

• A different alternative must consist of different overall product functionality.

Use Case Diagrams

• Interactions supported by a product are cataloged in a use case description.
• Interactions are refined in a use case diagram.

Use Case Driven Iterative Development

• At each iteration, one or more use cases are selected for implementation.
• Iteration should be followed until the system is complete.
• Iterative development builds system functionality gradually through analysis, design, coding, testing, and evaluation.