1. Behavioral Modeling with UML
Behavioral Modeling with UML

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Today’s topic

3. Overview Structural modeling Behavioral modeling
Brief intro to design patterns

4. What does a class diagram represent?
User
name : string
string
buyer 1
seller 1
Has
Has
purchase
sale * *
Sale
price : integer
description : string

5. What does a class diagram represent?
User
name : string
string
Set of possible objects
Instances of each class
Set of possible configurations
Attribute values
Links between objects
buyer 1
seller 1
Has
Has
purchase
sale * *
Sale
price : integer
description : string

6. Pros/cons of class diagram
User
name : string
string
Pro: Abstract/General
Represents all possible objects/configurations
Con: Complex
A lot of possibilities to consider
buyer 1
seller 1
Has
Has
Sometimes easier to
reason about
objects (more concrete)
than about
classes (more abstract)
purchase
sale * *
Sale
price : integer
description : string

7. Object Diagrams Class Diagram Object Diagram Sale price : integer
description : string
surface sale : Sale
price = 500
description = "Microsoft Surface"
ipad sale : Sale
price = 600
description = "Apple iPad"
galaxy sale : Sale
price = 250
description = "Samsung Galaxy"

8. Object Diagram Notation
name
Colon
separator
type
Attribute
value
galaxy sale : Sale
price = 250
description = "Samsung Galaxy"
Underline denotes object (as opposed to class)
Object
Corresponding class:
Sale
price : integer
description : string

9. Object diagram is snapshot of system at point in time
Object Diagrams
Class Diagram
Object Diagram
Sale
price : integer
description : string
surface sale : Sale
price = 500
description = "Microsoft Surface"
ipad sale : Sale
price = 600
description = "Apple iPad"
Object diagram is snapshot of system at point in time
galaxy sale : Sale
price = 250
description = "Samsung Galaxy"

10. What about associations?
Class Diagram
Object Diagram
User
name : string
string
buyer 1
seller 1
ipad sale : Sale
price = 600
description = "Apple iPad"
Has
Has
purchase
sale * *
Sale
price : integer
description : string

11. First, let’s add users Class Diagram Object Diagram User name : string
string
alice : User
name = "Alice" =
buyer 1
seller 1
ipad sale : Sale
price = 600
description = "Apple iPad"
Has
Has
purchase
sale * *
Sale
price : integer
description : string
bob : User
name = "Bob" =

12. Now, make Alice a seller Class Diagram Object Diagram Add a link User
name : string
string
alice : User
name = "Alice" =
Has
seller
sale
Add a link
buyer 1
seller 1
ipad sale : Sale
price = 600
description = "Apple iPad"
Has
Has
purchase
sale * *
Sale
price : integer
description : string
bob : User
name = "Bob" =

13. No multiplicities on links
Now, make Alice a seller
Class Diagram
Object Diagram
User
name : string
string
alice : User
name = "Alice" =
No multiplicities on links
seller
buyer 1
seller 1
Has
sale
ipad sale : Sale
price = 600
description = "Apple iPad"
Has
Has
purchase
sale * *
Sale
price : integer
description : string
bob : User
name = "Bob" =

14. Lastly, make Bob the buyer
Class Diagram
Object Diagram
User
name : string
string
alice : User
name = "Alice" =
seller
buyer 1
seller 1
Has
sale
ipad sale : Sale
price = 600
description = "Apple iPad"
Has
Has
Has
buyer
purchase
purchase
sale * *
Sale
price : integer
description : string
bob : User
name = "Bob" =

15. Is this valid? alice : User name = "Alice" email = "alice@memphis.edu"
seller
buyer
User
name : string
string
Has
purchase
Has
ipad sale : Sale
price = 600
description = "Apple iPad"
buyer 1
seller 1
sale
sale
Has
Has
surface sale : Sale
price = 500
description = "Microsoft Surface"
Has
purchase
sale * *
purchase
Sale
price : integer
description : string
Has
buyer
seller
bob : User
name = "Bob" =

16. Is this valid? Yes! alice : User name = "Alice"=
Yes!
seller
buyer
User
name : string
string
Has
purchase
Has
ipad sale : Sale
price = 600
description = "Apple iPad"
buyer 1
seller 1
sale
sale
Has
Has
surface sale : Sale
price = 500
description = "Microsoft Surface"
Has
purchase
sale * *
purchase
Sale
price : integer
description : string
Has
buyer
seller
bob : User
name = "Bob" =

17. How ’bout this? alice : User name = "Alice"=
buyer
User
name : string
string
Has
purchase
ipad sale : Sale
price = 600
description = "Apple iPad"
seller
sale
chuck : User
name = "Chuck" =
Has
buyer 1
seller 1
sale
Has
Has
Has
purchase
sale * *
Sale
price : integer
description : string
seller
bob : User
name = "Bob" =

18. How ’bout this? No! 1 seller per sale! alice : User name = "Alice"=
No! 1 seller per sale!
buyer
User
name : string
string
Has
purchase
ipad sale : Sale
price = 600
description = "Apple iPad"
seller
sale
chuck : User
name = "Chuck" =
Has
buyer 1
seller 1
sale
Has
Has
Has
purchase
sale * *
Sale
price : integer
description : string
seller
bob : User
name = "Bob" =

19. Note: No inheritance in object diagrams
User
name : string
string
zed : User
name = "Zed" =
wolverine : Spy
name = "Logan" =
alias = "Wolverine"
Spy
alias : string

20. Class and object diagrams model structure
What the objects are
How they’re connected
What attributes/operations they have
But structure isn’t everything
What else might you want to model?

21. Behavioral Modeling How objects interact Two notations:
What messages are exchanged over links
Messages = method calls/returns
Message protocols
Scenarios of interaction
Two notations:
Communication diagram
Sequence diagram

22. Communication Diagram
From The Unified Modeling Language Reference Manual, Second Edition by Rumbaugh et al.

23. Communication Diagram
From The Unified Modeling Language Reference Manual, Second Edition by Rumbaugh et al.

24. Communication Diagram
Binds to link
Binds to object

25. Communication Diagram

26. Communication Diagram

27. Communication Diagram

28. Communication Diagram

29. Sequence Diagram
From The Unified Modeling Language Reference Manual, Second Edition by Rumbaugh et al.

30. Sequence Diagram
From The Unified Modeling Language Reference Manual, Second Edition by Rumbaugh et al.

31. Sequence Diagram

32. Sequence Diagram

33. Sequence Diagram

34. Sequence Diagram

35. Sequence Diagram

36. Sequence Diagram

37. Sequence Diagram

38. Sequence Diagram

39. Communication and sequence diagrams both represent scenario
Why prefer one over other?

40. Communication and sequence diagrams both represent scenario
Why prefer one over other?
Communication includes structure
Sequence easier to read message exchange

41. So what are all these notations good for?
Reasoning about your own designs
Understanding other people’s designs
And design patterns!

42. Required reading for software designers
“Gang of Four” (GoF) book
23 patterns
Template solutions to common problems

43. Common Problem: Many objects interconnected in complex ways
From Design Patterns: Elements of Reusable Object-Oriented Software (Gamma et al., 1995)

44. Common Problem: Many objects interconnected in complex ways?

45. Mediator Pattern
From Design Patterns: Elements of Reusable Object-Oriented Software (Gamma et al., 1995)

46. Mediator Pattern
From Design Patterns: Elements of Reusable Object-Oriented Software (Gamma et al., 1995)

47. Application of Mediator Pattern
From Design Patterns: Elements of Reusable Object-Oriented Software (Gamma et al., 1995)

48. Application of Mediator Pattern
From Design Patterns: Elements of Reusable Object-Oriented Software (Gamma et al., 1995)

49. Application of Mediator Pattern
From Design Patterns: Elements of Reusable Object-Oriented Software (Gamma et al., 1995)

50. Summary Structural modeling with Behavioral modeling with
Class diagrams
Object diagrams
Behavioral modeling with
Communication diagrams
Sequence diagrams