Advanced Use Case Modeling

1
Advanced Use Case Modeling

• ActorActor, Use CaseUse Case, Include, Extend
  Rationalizations
• Concepts and Examples
• Thinking about opportunities for actor
  generalization factoring out common behavior

2
Actor Case Rationalization (continued)

• Customer, SalesAgent -gt Buyer Abstraction
  Customer, SalesAgent
• (Inherited interactions specialized actions)

3
Use Case Rationalizations

• Generalization overriding features in children
• (In UML 2, use cases do not have attributes and
  operations)

4
Documenting Generalization in Specialization

• Example Parent (Find Product), Children
  (FindBook, FindCD)
• (Generalization is abstract if the parent
  has no flow of events or incomplete flow of
  events, simplifies showing inheritance and
  overriding)

5
Documenting Generalization in Specialization
(continued)(tag language)

6
Base Use Case and Included Use Case

• Maintainability, Reusability
• Specify the point for inclusion (like a function
  call)

7
Extended and Extending

• Extended use case extending use case, the
  extension point is just a hook, not part of the
  flow. Extension use cases are generally not
  complete use cases.

8
Avoiding Unnecessary Rationalizations

• Use case generalization should be avoided unless
  abstract rather than concrete use cases are used
  to avoid burdening the child use case with
  unnecessary complexity
• Verification and validation is harder with
• Generalization, particularly, the actor
  generalization
• Too many includes
• Extends (even modelers may not understand
  ltltextendgtgt semantics

9
Avoiding Top-Down Decompositions