ch3 class modeling

8/12/2019 CH3 Class Modeling

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Software Engineering Lab

2006-04-12

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SE LAB

KAIST

Tae-Hoon Song

CH3. Class Modeling

Michael Blaha, James RumbaughObject-Oriented Modeling and Design with UML


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Software Engineering LAB

Contents

Introduction

Background Object and class concepts

Link and association conceptsGeneralization and inheritance

Navigation of class modelsSummary


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Introduction

Object-oriented modeling and design

Way of thinking about problems using modelsorganized around real-world concepts

Class modelingDescribe the static data of objects and theirrelationships to one another

Define each conceptPresent the corresponding UML notation


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Background

Model

Abstraction of something for purpose ofunderstanding it before building itViewpoints

Class modelStructure of objects in a system (class diagram)

State modelAspects of an object that change over time (state diagram)

Interaction modelObjects in a system cooperate to achieve broader results(Use case/sequence/activity diagram)


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Object and class concepts (1/4)

Object

Concept, abstraction, or thing with identityProper nouns or specific reference in problemdescription

ClassGroup of objects with

Same properties (attributes)Behavior (operations)Kinds of relationshipsSemantics


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Class diagrams

Graphic notation for modeling classes and theirrelationships

Object diagramsGraphic notation for individual objects and theirrelationships

Rookie :RookieTaeHoon :Rookie SeokJoong :Rookie

lass Objects


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Value : piece of data

Attribute : value for each objectOperation

Function or procedure that may be applied to or byobjects in a classAll objects in a class share the same operations

lass

Rookiename :string

birthdate :date

enroll

( types ) TaeHoon:Rookiename=Tae Hoonbirthdate =6 Dec 1975

( attributes )

( operation )

Object

( values )


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Summary of notation for class

ClassNameattributeName1 : dataType1 = defaultValue1

attributeName2 : dataType2 = defaultValue2

operationName1 ( argumentList1 ) : resultType1

operationName2 ( argumentList2 ) : resultType2


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Link and association concepts (1/8)

Links and associations

Link Physical or conceptual connection among objectsInstance of an association

AssociationGroup of links with common structure and commonsemanticsSet of potential links

Links and associations

: Verb in problem statements


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Links and associations (Contd)

* *RookienameCompany

name lass diagram

Hoon:Rookiename=Hoon

OwnStock

Joong:Rookiename=Joong

Seok:Rookiename=Seok

MS:Companyname=MS

SUN:Companyname=SUN

Object diagram

( Association name )

( Association )

(Link)


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Multiplicity

Constrain the number of related objectsAssign a multiplicity to an association end

Husbandname

Wifename

lass diagramHasWife

1 1

Seok:Husbandname=Seok

Hee:Wifename=Hee

Hoon:Husbandname=Hoon

Lyn:Wifename=Lyn

Object diagram

(Multiplicity )

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Association end names

Each end of an association can have a nameConvenience for traversing associations

Person CompanymployeeWoksFor 0..1*

employer( Association end names )

employeeTaehoonSeokjoongYoungseok

employerMSMS

IBM

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Ordering

Indicate an ordered set of objectsProvide an explicit order

Permitted only for binary associations

Screen WindowVisibleOn 1

{ordered}

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Bags and Sequences

Permit multiple links for a pair of objectsBag

Collection of elements with duplicates allowed

SequenceOrdered bag

Permitted only for binary associations

Itinerary Airport

{sequence}

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Association classes

Derive identity from instances of the constituentclassesHave attributes and operationsParticipate in associations

User Workstation

Authorizationpriority

startSession

( Association class )

(Dash line )

Workstation 1home

(Participating in anassociation )

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Qualified Associations

Disambiguate the objects for a many associationend Select among the target objects, reducing theeffective multiplicity, from many to one

(Qualified )

Bank Account..1accountNumber 1

(Not qualified )Bank

Account

accountNumber

(Qualifier )

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Generalization and inheritance (1/3)

Definition

GeneralizationRelationship between a class (the superclass ) and oneor more variations of the class (the subclass )

InheritanceEach subclass has the features of its superclassUse of generalization

Support for polymorphismStructure the description of objects

Enable reuse of code

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Overriding features

Refines and replaces(Subclass feature superclass feature)

To specify behavior that depends on the subclassTo tighten the specification of a featureTo improve performance

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Tankguncannonfiremove

Truckboxbosbring

Crane jackboslift

Vehicleengine

door wheeldisplacementmove

(Generalization )

(Overriding Feature )

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Navigation of class models (1/3)

Navigation

Express the behavior of navigating among classesExercise a model and uncover hidden flaws andomissions

Traverse the constructs in class models with OCLObject Constraint Language (OCL)

AttributesTraverse from an object to an attribute value

Vehicle . displacement

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Object Constraint Language (OCL) (Contd)

OperationsInvoke an operation for an objectTank . Fire

Operate on entire collectionsVehicle . Tank . gun -> sum ( )

Simple associationTraverse an association to a target end

Person . employee

Qualified associationMake a more precise traversal

Bank . accountNumber [060411]

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Object Constraint Language (OCL) (Contd)

Association classFind the constituent objects or the multiple links of anassociation class

GeneralizationTraverse a generation hierarchy

FiltersFilter the objects in a set

Vehicle . displacement -> select ( amount > cc 2000 )

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Summary

Class model

Static data structure of objects and theirrelationships to one another

ConceptsObject : concept, abstraction, identified thingClass : group of objects (attribute, behavior, relations)

Link and association : set of potential linksGeneralization : relationship between the superclass andthe subclasses

Navigation of class model : behavior of navigation amongclasses

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The endThe end

Thank youThank you

ch3 class modeling

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