1. Class Diagram

2. Class Diagram
A class diagram shows the existence of classes and their relationships in the logical view of the system.
Graphical presentation of the static view.

3. Classes A class is represented as a three-part box Class Name
Attributes
At conceptual level it is a piece of information associated with the class that can be accessed and possibly modified
Corresponds to a field at the implementation level

4. Operations
The processes the class can carry out (methods at implementation level)
- Basic operations (such as getValue) on attributes can be omitted (they can be inferred)

5. Classes Attribute syntax: visibility name: type = defaultValue
Operation syntax: visibility name(parameter-list): return-type
Customer
Class Name
Name
address
Attributes
+creditRating():String
Operations

6. Path name (Package-name :: Class-name)
Visibility:
- public +
- protected #
- private –
Class Names:
Simple
Path name (Package-name :: Class-name)
Window
Banking :: CheckingAccount
For abstract classes, class name is written in italic: Customer

7. Abstract Class
Abstract Operation

8. Class Diagram - Relationship
Association: bi-directional semantic relationship
Aggregate: a whole and part relationship
Generalization: inheritance relationship
Dependency: single-directional relationship between a client class and a supplier class/interface
Realize: single-directional relationship. A class realizes the operations offered by the interface.

9. Structural Modeling: Core Relationships

10. Structural Modeling: Core Relationships (cont’d)

11. Associations Associations are shown as lines between classes
An association shows a relationship between instances of two classes
Each association has two roles (one for each direction)
A role can be explicitly named with a label
Roles have multiplicity showing how many objects participate in the relationship

13. Associations can have multiplicities:
A fixed value (such as 1 or 3)
Many denoted by * (unlimited number)
A range of values 0..1 or 3..*
A set of values 2,4,8

14. Adds attributes and operations to an association
Association Class
Adds attributes and operations to an association
Allows exactly one instance of the association class between any two objects
Can use an actual class instead, if you need more
0..4
10..20
Student
Course
Grade

15. 0..*
1..*
Company
Person
employer
employee
Job
description
dateHired
salary

16. Qualified Association
Association can be keyed by the value of the qualifier.
A qualifier is used to reduce the scope of an association.
A qualifier in an association solves the lookup problem.
qualifier 1 *
finds
Reservation
Clerk
Confirmation Number

17. Constraints Represent further restrictions on associations or classes
A constraint is shown as a text string enclosed in braces { }.
A constraint is a restriction on one or more values of (part of) an object-oriented model or system.
{ordered }
Serves
Bank Teller
Customer
Chooses
Academic
High School
Student
{ or }
Chooses
Commercial

18. 1 1 1 1 * * * 1 Meal - - - - - - - - { or } - - - - - - - - -
{ precedes } 1 1 1 1
Soup
Salad
Main Course
Dessert *
Member-of *
Committee
Person
{ subset }
Chair-of * 1

19. ATM_Withdrawl Account
customer : id
amount : Money
{amount is multiple of $20}
Account
balance : Money

20. Aggregation and Composition
Aggregation is a part-of relationship.
Composition is also a part-of relationship, but part and whole live and die together
In aggregation, parts may be added or removed, they may survive even after the whole is dead while in composition parts are contained in the whole and die with the container.
Aggregation is more loosely coupled than composition.

21. 1 1 2 1 1 Computer shows aggregation Speaker CPU Keyboard Monitor
Mouse

22. Table
shows
composition 1 4
Leg
Table Top

23. Generalization Sharing mechanism based on
Customer
Sharing mechanism based on
a hierarchical relationship between classes.
Subtype is a specialization
of the supertype.
Is-kind-of Relationship
name
address
creditRating():String
indicates
generalization
Corporate
Customer
Personal
Customer
creditCardNumber
contactName
creditRating
creditLimit
remind()
billForMonth(Int)

24. Generalization Relationship
vehicle
land vehicle
water vehicle
car
amphibian
vehicle
ship

25. Dependency Relationship

26. Realization Relationship
Realization is the relationship between a class and an interface. The class is said to realize the operations in the interface.