1. Software Systems Design – 4 Class Diagrams (dynamic)
Klaas Sikkel
Software Systems
Design - 4

2. Today’s topic
Software Systems
Design - 4

3. Contents From use cases to class diagrams “Analysis class diagram”
Collaborations
Communication diagram
Use case class diagram
“Analysis class diagram”
Integration of use case class diagrams
Further analysis
Software Systems
Design - 4

4. Positioning in the design thread
Part 4 (this lecture) gives a more structured approach to deriving a class diagram.
However, it’s hard to apply if have no experience with class diagrams
Therefore we did Part 3 (static class diagrams) first, so that you have some idea about the entity classed that could be involved.
Software Systems
Design - 4

5. Agate Ltd. (Case A in Bennett et al.)
Agate Ltd. runs publicity campaigns.
For one client there can be multiple campaings
Each campaign consists of a number of different clients
Software Systems
Design - 4

6. Use case Adding a new advert to a campaign Bennett Fig. 7.13
Software Systems
Design - 4

7. A Collaboration
Bennett Fig. 7.15
Software Systems
Design - 4

8. A Collaboration Boundary Control object object Entity objects
Software Systems
Design - 4

9. BCE Objects/Classes
Boundary object: provides interface with the outside world
Control object: implements the logic involved in realising this use case
Entity object: ‘regular’ object inside the systems
Software Systems
Design - 4

10. Communication diagram (1)
Bennett Fig.7.16
Software Systems
Design - 4

11. Communication diagram (2)
Bennett Fig. A3.2
Software Systems
Design - 4

12. Corresponding class diagram (use case class diagram)
Bennett Fig. A3.3
Software Systems
Design - 4

13. Communication diagram notations (1)
Standard Com.d. notation
BCE notation boundary / control / entity object
:Campaign
Software Systems
Design - 4

14. Communication diagram notations (2)
*: loop; repeat message for all instances
Sequential numbering of messages 1, 2, 3, … n
Hierachical numbering of messages
3, 3.1, 3.1.1, , , 3.1.2, etc
Software Systems
Design - 4

15. BCE style with hierachical numbering
Bennett Fig. A3.11
Software Systems
Design - 4

16. Use case class diagram
Bennett Fig. A3.12
Software Systems
Design - 4

17. Other use case CDs (only entity classes)
From Bennett, Figs. 7.17, A.6
Software Systems
Design - 4

18. Combined class diagram (“Analysis class diagram”)
Bennett Fig. A3.13
Software Systems
Design - 4

19. Overview of method For relevant use cases
1.1. Get extended use case description
1.2. Design communication diagram
1.3. Derive use case class diagram
Combine use case CD’s into analysis CD
Improve analysis class diagram
3.1. Verify correctness (does is match the case description)
3.2. Add further details (data elements, further use cases)
Software Systems
Design - 4

20. Overview of method (contd.)
3.1. Verify correctness (does is match the case description)
We will do this in the lab exercise
3.2. Add further details (data elements, further use cases)
See Bennett for an example
Software Systems
Design - 4

21. Static vs. Dynamic Class diagrams
Static (D-3)
Abstracts from methods
More detailed semantics of generalization
A model of information about the real world that should be represented in the system
Dynamic (D-4)
Includes methods
Abstracts from data types and generalization details
Constructed by analysing how the system realizes various use cases
Software Systems
Design - 4

22. Exercise
Service department of internetshop RedHot: handling of products that need repair
If a product is broken, the customer calls the Customer Service. An employee creates a service record. The customer receives an with instructions for sending it in, and label for sending a parcel free of charge.
Software Systems
Design - 4

23. Draw comm. diagram for this use case
Actor action
System response 1 2
Displays list of customers 3
Selects the customer 4
Displays products purcha-sed by this customer 5
Selects product to be serviced 6
Creates service record 7
Enters problem descr. 8
Stores problem description 9
Creates customer instructions 10
Sends to customer
Software Systems
Design - 4