1. School of Computer Science and Engineering
Class Diagrams
Bong-Soo Sohn
Assistant Professor
School of Computer Science and Engineering
Chung-Ang University

2. CLASS in UML Class Name Attribute1 Attribute2 … Operation1 Operation2
responsibility

3. CLASS in UML Class name WashingMachine First letter is upper-case
No empty space in a class name.
with package name?
package_name::class_name
Ex) HouseholdAppliances::WashingMashine
WashingMachine

4. myWasher:WashingMachine
CLASS in UML
Attribute
Attribute Names
Additional information (attribute vale) can be specified.
Ex) capacity:Integer = 8
WashingMachine
brandName
modeName
serialNumber
capacity
Instance of WashingMachine
myWasher:WashingMachine
brandName = “TROMM”
modeName = “WD-R121XH” serialNumber = “LG57774”
capacity = 12

5. CLASS in UML Operation WashingMachine brandName class methods modeName
addClothes()
removeClothes()
addDetergent()
turnOn()
brandName
modeName
serialNumber
capacity
WashingMachine
class methods
first letter is lower-case
Additional information (e.g. signature) can be specified. Ex) addClothes( C:String )

6. Additional information (signature) in operations
WashingMachine
brandName
modelName
serialNumber
capacity
addClothes( C:String )
removeClothes( C:String )
addDetergent( D:Integer)
turnOn( ):Boolean
- Parameter name and type
- Return type

7. Stereotype WashingMachine WashingMachine WashingMachine brandName
. . .
addClothes()
WashingMachine
<<id info>>
brandName
modelName
serialNumber
<<machine info>>
capacity
<<clothes-related>>
addClothes()
removeClothes()
addDetergent()
<<machine-related>>
turnOn()
If the lists of class attributes and operations are long, stereotype can be used to separate the list for better understanding.
stereotype
one or extensibility machanisms in UML
allow designers to extend the vocabulary of UML in order to create new model elements
Notation :<<stereotype_name>>

8. Responsibility and Constraints
Use when inserting constraints a class has to follow.
Notation : text in ‘{ }’
WashingMachine
<<id info>>
brandName
modelName
serialNumber
<<machine info>>
capacity
<<clothes-related>>
addClothes()
removeClothes()
addDetergent()
<<machine-related>>
turnOn()
Responsibility :
Take dirty clothes as input and produce clean clothes as output
{capacity =5 or 8 or 10 Kg}
Explain what class has to do

9. Note WashingMachine brandName modelName serialNumber capacity
<<id info>>
brandName
modelName
serialNumber
<<machine info>>
capacity
<<clothes-related>>
addClothes()
removeClothes()
addDetergent()
<<machine-related>>
turnOn()
Responsibility :
Take dirty clothes as input and produce clean clothes as output
Refer to Government Standard EV on generating serial numbers
{capacity =5 or 8 or 10 Kg}
Note
Use when inserting additional information.

10. Class Modeling Class name attribute1 attribute2 … operation1
Nouns during conversation with clients
Class name
attribute1
attribute2 …
operation1
operation2
responsibility
Nouns during conversation with clients
, which are related to class name.
Verbs during conversation with clients의뢰

11. Example : modeling basketball game

12. Example : modeling basketball game

13. Basketball Game Conversation with coach
noun
ball, basket, team, players, guards, forwards, cener, shot, shot clock, three-point line, free throw, foul, free-throw line, court, game clock
verb
Shoot, advance, dribble, pass, foul, rebound
Initial Class Diagram

14. Initial class diagram Ball diameter volume dribble() shoot() pass()
advance()
Player
name
height
weight
dribbleBall()
passBall()
shootBall()
rebound()
foulOpponent()
Forward
does most of the
intermediate
range shooting
and rebounding
Guard
does most of the
dribbling and passing
Team
Basket
ShotClock
{pro = 24 sec
college = 35sec
Int’l = 30 sec}
center
stays near basket,
shoots from
close range
Foul
Shot
Court
GameClock
{pro = 4 12-minute quarters
college and Int’l=2
20-minute halves}
ThreePointLine
FreeThrow
Duration
{pro = 48minutes
college and Int’l =
40 minutes
FreeThrowLine

15. Association
When classes are connected together conceptually, that connection is called association

16. Association

17. Constraints on Association

18. Association Classes
Association can have attributes and operations, just like a class.

19. Link
An association may have instances, just as an object is an instance of a class

20. Multiplicity
The number of objects from one class that relate with a single object in an associated class.
One – to – one
One – to – many(*)
One – to – one or more(*)
1..*
One – to – zero or one
One – to – a bounded interval
ex. one – to – 5 through(..) 10
One – to exactly n
ex. One – to – 10
One – to – a set of choices
ex. One – to – 5 or(,) 10

21. Multiplicity
Possible multiplicities
and how to represent them in UML

22. Reflexive Association
Association with itself

23. Inheritance and Generalization
Is a kind of
inheritance,
Generalization
subclass , superclass
root class, leaf class

24. abstract class
Class that does
not have an instance
italic font

25. Dependencies one class may use another.
The most common usage of dependency is to show that the signature of one class’s operation uses another class

26. More about class diagrams
집합연관(Aggregation)
복합연관(Composition)
문맥(Contexts)
인터페이스(Interface)
실체화(Realization)
가시성(Visibility)

27. Aggregations
A class consists of a number of component classes

28. Constraints on Aggregations
Constraint to show that one component or another is part of whole

29. Composite A strong type of aggregation
Each component in a composite can belong to just one whole

30. composite structure diagram
Show class’s internal structure
Show components of a class

31. Interface and Realization
One entity (interface) defines a set of functionalities as a contract, and the other (class) realizes the contract by implementing the functionality defined in the contract.

32. Visibility
+ : public
# : protected
- : private