1. Chapter 16: The Design Workflow Chapter 17: Design Classes
CS 426
Senior Projects in Computer Science
Chapter 16: The Design Workflow
Chapter 17: Design Classes
[Arlow and Neustadt, 2005]
University of Nevada, Reno
Department of Computer Science & Engineering

2. Outline The design workflow The design metamodel
Design workflow details
UP activity: architectural design
UP activity: design a class
Anatomy of a design class
Well-formed design classes
Inheritance, templates, & nested classes

3. The Design Workflow
Chapter 16 roadmap

4. The Design Workflow
Design emphasized in Elaboration and Construction phases

5. The Design Metamodel

6. The Design Metamodel

7. The Design Metamodel Design models are made up of Design subsystems
Design classes
Interfaces
Use case realizations (design)
[An early] deployment diagram

8. Artifact Trace Relationships

9. Should We Maintain Two Models?

10. Should We Maintain Two Models?
The analysis view is useful for:
Introducing new people to the project
Understanding the system long time after delivery
Understanding how the system satisfies requirements
Providing requirements traceability
Planning maintenance and evolution
Understanding the logical architecture of the system
Outsourcing the construction of the system

11. Should We Maintain Two Models?
Guidelines:
An analysis view should be preserved for large, complex, strategic, potentially long-lived systems
Is the system is small, not strategic, or has a short expected life, separate analysis and design models might be overkill
Caution though: many systems long outlive their projected life span

12. Design Workflow Detail

13. UP Activity: Architectural Design

14. Chapter 17 Roadmap

15. UP Activity: Designing a Class

16. What Are Design Classes?

17. Anatomy of a Design Class

18. Well-formed Design Classes
Characteristics of well-formed design classes
Complete and sufficient
Primitive
High cohesion
Low coupling

19. Inheritance Aggregation versus inheritance
Inheritance is the strongest form of coupling
Encapsulation is weak within a class hierarchy (fragile base class problem)
Inheritance is the most inflexible type of relationship

20. Inheritance

21. Multiple Inheritance

22. Templates

23. Templates

24. Templates

25. Templates

26. Nested Classes