1. Software Engineering Zhang Shuang zhangs@swc.neu.edu.cn

2. Object-Oriented Design (OOD)  Aim  Design product in terms of objects extracted during OOA

3. Object-Oriented Design Steps  OOD consists of four steps: 1.Construct interaction diagrams. The designer creates a sequence diagram or a collaboration diagram for each of the use case scenarios defined during the analysis phase.

4. Object-Oriented Design Steps  OOD consists of four steps: 2.Construct a detailed class diagram. The preliminary class diagram created during the analysis phase is elaborated to include a full list of methods (including their signatures and return types) and data members (including their types). Additional classes and relationships are added where necessary.

5. Object-Oriented Design Steps  OOD consists of four steps: 3. Construct a client-object relation diagram. The designer then arranges the classes in a diagram that emphasizes their hierarchical relationship; this corresponds to the motion of a control flow diagram (CFD) in structured analysis.

6. Object-Oriented Design Steps  OOD consists of four steps: 4.Complete a detailed design. The designer then specifies the algorithms to be implemented for each method, along with the internal variables and data structures required by each method.

7. Object-Oriented Design Steps  One of the main activities of software design is to partition the functionalities identified in the requirements specification and analysis phases into specific software modules.  Module  In traditional structured programming, a particular function or program in a particular language.  In object-oriented programming, an object, or perhaps a method associated with a particular object.

8. Elevator Problem: OOD  Step 1. Construct interaction diagrams for each scenario  Sequence diagrams  Collaboration diagrams  Comparison  Both show the same thing  Objects and messages passed between them  But in a different way

9. Normal scenario

11. Sequence Diagram

16. Case Study: Sequence Diagram Use case scenario: Login

17. Elevator Problem: OOD (contd)  Collaboration diagram

18. Zhang Shuang, zhangs914@163.com