UML Class Diagrams

1
Object Oriented Analysis
2
Outline

• Structural Modeling
• Class Diagrams and Object Diagrams
• Association
• Generalization ??? Classification
• Aggregation ??? Composition
• Models

3
Structural Modeling
4
What is structural modeling?

• Structural model
• ????????????????????????????????????? ???????????
  (Class) ???????? ???????????????????????
  (Relationship) ???????????
  (Attribute) ??? ?????????? (operation)

5
Structural Modeling Core Elements
6
Structural Modeling Core Elements (contd)
¹ An extension mechanism useful for specifying
structural elements.
7
Structural Modeling Core Relationships
8
Structural Modeling Core Relationships (contd)
9
Structural Diagrams

• ????????? Structural Diagrams
• static structural diagrams
• class diagram
• object diagram
• implementation diagrams
• component diagram
• deployment diagram

10
Static Structural Diagrams
11
Static Structural Diagrams

• ?????????????????????????????????? static
  relationships
• ????????? Static Structural Diagrams
• class diagram classifier view
• object instance diagram instance view

12
Class Diagrams

• Class diagrams
• ????????????????? Class ??????????????????????
  Class ??????????? logical view
• ????????????? UML class diagrams ??????
• Class, ???????????? Class ?????????????? Class
• ????????? Multiplicity ??? navigation
• ??????? Role
• ??????????????? association, aggregation,
  dependency, ??? inheritance

13
Classes in UML

• ???????? 2 ??????

Class name
Person
Attributes
attribute name type
Operations
operation name(parameter type) result type
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UML Syntax for Attributes

• visibility name type
• id String
• visibility public (), protected (), private
  (-)
• ??????????????????? ??????????????????????
• name ???? string
• type ??????????????? ??????????????

15
UML syntax for operations

• visibility name (parameter list)
  return-type-expression
• assignAgent (a Agent) Boolean
• visibility public (), protected (), private
  (-)
• ?????????????????????????????????????????
• name string
• parameter list arguments
• return-type-expression ??????????????? return
  ??????????????

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Attributes A Rule

• ???????? attributes ???????????? (simple)
• ???????????????? attributes ???????????????
  (Object)
• ??????????????? (class) ???? ?????????????????????
  ?????????????? association
• ?????????????????????????????? 2 ???? ??????
  foreign key attribute
• ?????? association

17
Object Instance Diagrams

• class diagram
• ???????? (name), ????????? (structure) ???
  ???????? (behaviour) ????????????????? (object)
• object instance diagram
• ????????????????????????
• ?????????????????????? 2 diagram
  ??????????????????????????????????????????????????
  ???? relational database ?????????????????????????
  ?????

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Objects in UML

• ???????? 2 ??????

Object name
TimPerson
Tim Person
TaxIDNo23003 NameTimLim Income30000.00 Ta
xPaid FALSE
Attributes
attribute name type value
Same Operations for all instances of a class
calcTax() calcTaxBal()
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An Object Instance Diagram
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Classes and Objects
City
Name String default
Country String default
Population integer default
setName (s String deault)
setPopulation(p integer default)
ltltinstanceOfgtgt
ltltinstanceOfgtgt
ltltinstanceOfgtgt
New York City
Sydney City
London City
Name London
Name New York
Name Sydney
Country USA
Country Australia
Country UK
Population 2,324,320
Population 5,734,012
Population 3,536,000
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Class Diagrams

• Associations
• Generalization
• Generalization ??? Classification
• Aggregation

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Association

• ???????????? (Relationship) ??????? instances
  ??? classes

name direction
association name
Order
Customer
dateReceived
issued by
isPrepaid
name

1
number String
address
price Money
creditRating( )
dispatch( )
Customer may make several orders
Order comes from one customer
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Associations

• ??????????? 1 ???? ??????????????? associations
• Association
• ??????????? ER relationship ??????????????????????
  ????????????? ??????? ???????????? (links)
  ??????? ????????????????????????

24
Naming associations

• ??????????? association
• ????????????????????????????????
• associated_with, has, is_related_to
• ?????????????????????? ????
• works_for, owns , issued by
• ??????????????????????? Association ????????????
  ???? ?????????????? diagram

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Associations on Class Diagrams
Owns
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Links

• ??????????????? ????????????????????? ??????
  links
• A link
• ???? instance ??? association
• ????????
• an association ????????????????? ????????????????
  instance (links) ??? association ????????
  ???????????? ????????????????????????
  ???????????????????????? ????????????????????????

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Objects Links
YouPerson
MePerson
NameJane Address22 Holly Pl Telephone[phone]
NameDennis Address41 High St Telephone[phone]
Owns
Owns
Owns
OursCar
MineCar
ManufacturerSaab Model95 RegistrationYRT833
ManufacturerMazda Model626 RegistrationYYX391
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Association Multiplicity

• multiplicity
• ??????? ??????????????? instances (objects)
  ???????????? ????????????????????? instance
  (object) ????????????????????

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Association Multiplicity
1
1..
Class
Class
exactly one
one or more
0..1

Class
Class
many (zero or more)
zero or one/at most one
2 ..4
Class
as specified
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Example of Multiplicities


Student
University
1
Heart
Body
2-3
Bicycle
Wheel

1..
1..
Account
Owner


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Associations, Objects Classes

• ?????? association ?????????? 2 ????? ????????
  link ?????????? 0 ??? 1 link
• ??????? 2 ????? ????????????????? 1 association
  (Multiple Assoications) ??? association
  ?????????????????????????????????????????????
  association
• Multiple associations ???????????????????
  ???????? associations

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Roles

• role
• ??????? ????????????????????????????? association
  ???????????????????????????????????????
  association
• ??????????? role ??????????????????
  (?????????????????? association ??????????? role
• ????????????????????? Role ??? associations
  ???reflexive (Reflexive associations)

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Role names

• Role ???? ????????????????????? association

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Association Names Roles

• association ??????????????????????????????? role
  ?????????????????????????????????????
• ???????????????? association ?????????????????????
  ?? role ???
• ?????????????????????????? association (??????
  roles) ??????????????????????? association ???

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Role names

• ????????????????????? Role ??????????????????
  link ???????????????????????????????

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A Reflexive Association

• association ???????????????????????

Person
Parent
Name Address Telephone
2
Role name
Child

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Ternary Associations

• A ternary association
• ???? assocation ????????????? 3 ????
• ????????????????????? ternary relationship ??ER
  modelling ??????????????? ???
• ???????????????????????????????????
  ?????????????????????????????

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Ternary Associations
Vendor
Customer
Product
Sale
Ternary association
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Ternary Association Multiplicity

• multiplicity ??? ternary associations
• ???????????? binary ??? unary associations
• ??????? ??? many ???????????????????????
  (participating)

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N-ary Associations

• ????????????? association ????????????????????????
  ???????????
• ??????????????????????? 2 ?????????? (???????
  ternary) ???????? n-ary associations
• ??? Associations ??????????????????? 0
  ???????????????

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Summary Basic notation for associations
Association name
mult1
mult2
Class A
Class B
role_A
role_B

• ????????????

contains

1
Order
Order Line
line items
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Association Classes

• Link ???????????? ????????????????????????????????
  ???? attribute ????????????
• attribute ???????????????? association ??????
  association class ????????????????????????????????
  ???? ???????????????whenever it exists or has
  meaning when the link itself exists (rather than
  just the objects linked) - ??????????????????
  many-to-many associations

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Association Classes
Student
Subject
Enrolment
ID Name Address Telephone
Code Name Credit


Result
Mark
Association class
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Association Classes

• association class ?????????????????? associations
  ????? ??????????????????????????????????

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Association Classes
Customer
Product
Purchase
Name Address Telephone
Number Name Price


Guarantee
0..1
Date Length Conditions
Claim

Association class
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Qualified Associations

• qualified association
• ??????? association ????????????????????
  attribute ??????????? qualifier
• ??????? qualified association ????????????????????
  ? weak entity type ?? ER

47
Qualified Associations
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Qualified Association
Tournament
Prize
Year Position
0..1
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Qualified association
Organization
Company
Function
Person

• ABC Inc. President Roger Rabbit
• ABC Inc. Vice President Finances Joe Savemoney
• ABC Inc. Member of board John Walker
• ABC Inc. Member of board Susi Sanssouci
• ABC Inc. Member of board Karl Eichbaum
• XYZ Inc. President Donald Duck

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Class Diagrams Hints

• class ???????????????????????????????? diagrams
• Diagrams ????????????????????????
• ?????????????????????
• ????? associations ????????????
• ???? attributes ??? operations ???????????????????
  ?
• ????????????????? diagram ???? ??????????

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Difference between attributes and associations

• Conceptual perspective
• ???????????????????
• Attributes ???????????? (single-valued)
• Specification/implementation perspective
• Attribute ??????? (Value) ????????????????
  (References)
• ???????? share ??????? attribute values ?????????
  instances ???????????????????????
• Often Stores simple objects
• Numbers, Strings, Dates, Money objects

52
Class diagrams (cont.)

• Associations
• Generalization
• Generalization ??? Classification
• Aggregation

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Generalization

• ???????????????????
• Generalization ?????? classes ????????????????????
  ????????????? (class Hierarchy) ???????
  similarities ??? differences
• ??????????????????????????????????????? classes
  hierarchy ??? superclasses ?????????????????????
  ?????? subclasses
• ???? kind-of relationship

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Inheritance and Polymorphism

• subclass ??????????????????? (inherits)?????????
  attributes, operations ???associations ?????
  superclass ?????????
• ??????????????? ??? attribute ???? operation ???
  superclass ?????????????????????????
  subclass ????????? overrides
  ???????????????????? superclass -
  ?????????????? polymorphism

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Superclasses and Subclasses

• Superclass ????????? attributes, operations ???
  associations ?????????? subclasses ????????????
• Subclasses ?? attributes, operations ???
  associations ??????????????????
  ????????????????????????????????? attribute,
  operation ???? relationship ???????????
  superclass ????????????

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A Generalization Hierarchy
Geometric_Figure
Superclass
X_Position Y_Position
Ellipse
Circle
Rectangle
Major_Axis Minor_Axis
Radius
Width Height
Subclasses
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Single Multiple Inheritance

• generalizations ????????? class hierarchies
  ???????? subclass ??????? 1 superclass -
  ???????? single inheritance
• ???????????????????? subclass ??????????????? 1
  superclass - ???????? multiple inheritance

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Multiple Inheritance
Employee
GeneralStaff
ProfStaff
FullTime
PartTime
Subclass with two superclasses
Academic
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Multiple Inheritance
Vehicle
Furniture
Wheelchair
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Specialization

• Specialization
• ???????????????????????? generalization
  ???????????????? ????????????????????????????????
• Generalization ???????????????????????????? ???
  (sub)classes
• Specialization ?????????? ????????????????????????
  ? (super)classes ??????????? subclasses

61
Class diagrams (cont.)

• Associations
• Generalization
• Generalization ??? Classification
• Aggregation

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Generalization and Classification ( is_a?)

• 1. Shep is a Border Collie.
• 2. A Border Collie is a Dog.
• 3. Dogs are Animals
• 4. A Border Collie is a Breed.
• 5. Dog is a Species
• 12 Shep is a Dog
• 123 Shep is a animal
• 14 Shep is a breed?????
• 25 A Border Collie is a Species?????
• Generalization is transitive (is kind of)
• Classification is not transitive (is instance of)

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Class diagrams (cont.)

• Associations
• Generalization
• Generalization ??? Classification
• Aggregation

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Aggregation

• Aggregation
• ?????????????????? association ???????????????????
  ?????????????? association ???????
• ?????????????? ?????????? ??????????????????
• ???? part-of relationship

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Notation for aggregation
Class A
Class A
Class B
????
Class C
Class C
Class B
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Example Aggregation
Book
1
1
Aggregation
1
0..1
1

Chapter
End
Front
1
1
1
1
1
0..1
0..1

Title
Preface
Appendix
Index
67
Example Aggregation
Company
Unit

Department


Group
works for

Employee
68
Aggregation

• ????? 2 ?????? Aggregation ??? Composition
• Aggregation
• ??????? ?????????? ??????????????????
• ???? Car ?? engine ???wheels ??????????????
• Composition
• ????????????????? ?????????????????????????
• ?????? message ??????????????????????????????????
  ???????????????????????????
• ??? delete ?????????????????????????
  ????????????????? delete ??????????

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Aggregation Composition

• ??????????????????? transitive
• ???????? A ???????????????? B ??? B
  ???????????????? C ???? A ????????????????
• ???? ?????????????????????????????? ?????
  ??????????????????????????? ????
  ?????????????????????????????????
• ??????????????????? Anti-symmetric
• ???????? ?????????????????????????????????????????
  ??????????????????
• ???? ??????????????????????????????
  ????????????????????????????????????

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Aggregation and composition
Polygon
Aggregation
1
1
Composition
1
GraphicsBundle
3..
color texture
Point
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Association and Aggregation

• Question Association ???? Aggregation?
• Answer ???? Aggregation
• ??????????????????? part of
• Operation ????????????????????????????????????????
  ????????????????????????????????????????????

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Generalization and Aggregation

• Question Generalization ???? Aggregation ?
• Answer ???? Generalization
• ??????????????????? kind of
• ?????????????????? or
• Answer ???? Aggregation
• ??????????????????? part of
• ?????????????????? and

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Class Diagram - Example

• A zoo consists of a set of cages.
• Every cage is the home of at least 2 animals.
• Cages are located besides each other.
• Every cage has at most one left neighbor and at
  most one right neighbor.
• Animals can be reptiles, insects, and mammals.
• Mammals are elephants, monkeys, and tigers.
• Monkeys eat bananas.
• Tigers prefer meat.

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Class Diagram
RegistrationForm
Professor
name
tenureStatus
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Class Diagram Notation Summary
Association_name

1
signature
constraint
Role_name
Qualifier
discriminators
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Class Diagram Notation Summary (contd)
formal_arg
Parameterised ClassName
Instantiated ClassNameltactual_arggt
Instantiates
ClassName1
ClassName2
constraint
ClassName3
public protected - private null unspecified /
derived
ternary
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Models
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Three Perspectives

• Conceptual (OOA)
• ?????????????????????????????????
• ?????????? implementation
• Specification (OOD)
• ??????????????????????
• ????? Interfaces ??? software
• Implementation (OOP)
• ?????????? implementation (classes)

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Three Models

• Analysis Model
• Design Model
• Implementation Model