csc589 intro oo-object oriented analysis and design

8/7/2019 Csc589 Intro OO-OBJECT ORIENTED ANALYSIS AND DESIGN

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OO programming and UMLOO programming and UML

DesignDesign

Dr. Zhen JiangWest Chester University

E-mail: [email protected]


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OutlineOutline Introduction to object and class

I

ntroduction to UML Introduction to UML design


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Introduction to object and classIntroduction to object and class

Why OO programming? Look at this picture carefully

You need to identify it from VERY similarpictures in the next slide


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Why OO programming? Which one is shown before?

In the next slide, your partner will see theselected picture and other two picturestogether. Write down something to help yourpartner to pick up the same picturecorrectly.


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Why OO programming? Partners job


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Why OO programming? Which one?


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Why OO programming? From snapshot to the action


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Why OO programming? From snapshot to the action

3

2

1


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Whats object Identity

State

Behavior

S

equence Diagram Statechart Diagram

Messages and methods

Whats class Objects and Classes

Class Attributes

Operation (Method)

Interfaces

Interfaces and Implementation


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Wh

ats objectWh

ats object

Fundamentals ofObject-Oriented

Programming


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Whats objectWhats object

Conceptually, there are many ways to thinkof an object

something that can be seen or touched

a thing to which some action is directed something that performs an action

The structure and behaviour of similar

objects are defined in their common class

Objects have three properties: identity , state,

and behaviour


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Object Property 1:Object Property 1: IdentityIdentity

Identity is that property of an object whichdistinguishes it from all other objects

Most programming languages use variable

names to refer to objects Keep in mind, however, that an object may

not have a name; Similarly, an object might

have multiple names (aliases) For this reason, there is a subtle distinction

made between the concepts of "name" and

"identity"


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Object Property 2: StateObject Property 2: State

The state of an object encompasses all of thedescriptions of the object plus the current

values of each of these descriptions


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Example ObjectsExample Objects

There are many physical objects we canexamine right in this room

each person is an object

any chair is not an object each light bulb is an object

Any book is not an object

this room itself is an object (full or not)


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Whats the relationship amongWhats the relationship among

objects: Messages and Meth

odsobjects: Messages and Meth

ods A object executes a method when it

sends/receives a message

For example, we can ask/tell a dog to sit bysending him the message "sit"

In object-oriented programming, objects

send messages asking/telling others toperform behaviors -- those other objects

invoke the method corresponding to the

message in order to execute the desired

behavior


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Whats classWhats class

A class describes the common structure(attributes/state) and behaviour of its instances

For example,

3.14, 2.71, and 5.5 can be classified as Floats

the following shapes can be classified as Circles


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Classes and objectsClasses and objects

How would we describe the state, behaviour,and identity for each of these objects

We have looked at objects and we have seen

that objects can be "classified" into classes As programmers, we work with both classes

and objects from those classes

For example, we might write a stack classand create multiple stack objects for use in

our program


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In a 2D drawing package, circles have aradius, a line thickness, a line colour, and a

fill colour

Each individual circle (instance) drawn bythe user has its own value for each attribute

The programmer writes a Circle class and

the program instantiates a Circle objectevery time the user draws a Circle

a snowman made from 9

Circle instances


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Interface and ImplementationInterface and Implementation

The class interface is its external (public)view

The class implementation is its internal

(private) view It is convenient to think of the interface as

describing "what the objects of this class can

do" and the implementation as "how the

objects of this class do it"

The implementation of a class consists of all

the "behind the scenes" operations defined

in the interface of the class


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UML OverviewUML Overview

UML is a language for visualizing,specifying, constructing and documenting

the artifacts of a software system

The artifacts might include requirements,architecture, design, source code, project

plans, tests, prototypes, releases


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Light

On Off Turn on/off

True False

Turn_on

attributes: {True,

False}

operations/methods:

value

structure

Turn_off

Turn_on/off ( )


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Hiding DetailHiding Detail

Circle

area()

display()

Circle

radius: float

center_x: int

center_y: int

Circle

You can optionally leave out the attributes,operations, or both in a class icon:


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Class RelationshipsClass Relationships

Generalization Association

Association Class

Qualified Association

Ternary Association

Aggregation


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AssociationAssociation

Associations can be adorned with the multiplicity.

4..*Faculty Student

1


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AggregationAggregation

An aggregation is an association thatrepresents whole/part relationship

The whole end of the association

relationship is adorned with an opendiamond shape (e.g. X is part of Y)

e.g. door:Door is part of car:Car

X Y


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ConstraintsConstraints

Constraints on Object

Constraints on Relations (Ordering)

General Constraints (Dependency)


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Constraints on ObjectConstraints on Object

The constraints restricts the values thatobjects can be.

Example: No employees salary can exceedthe salary of the employees boss.

Employee

Sa

la

ry

Employer

Sa

la

ry

{salary


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Constraints on RelationsConstraints on Relations

(Ordering)(Ordering)

{Order} indicates that the elements of themany end of an association have an explicitorder that must be preserved.

Paper Author

{ordered}

11..

*


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UML class diagram is not objectUML class diagram is not object

diagramdiagram

Customer BankLoan

Other-Loan

Should we add relationbetween Bank and Other-Loans?Can Bank change Other-loans?

Instance of Loan and Other-Loans?


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UML class diagram is not dataUML class diagram is not data

flow chartflow chart

Customer Dealer

Product Manager

buy sell report

bargain

authorize

sign


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How to describe theHow to describe the

beh

aviors/actions of objects inbeh

aviors/actions of objects inUML class diagramUML class diagram

?

Person

sSNaddressemail

Faculty StudentCustomer Casher


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beh



Use case (stories): Each use case defines an interaction

between an actor and the system

Use case

Use case

Use case

Use case


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Scenarios of a use case Reception

Check

Failure

Authorized

Waiting

Success Failure

?

Order


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beh



In design, see

www.cs.wcupa.edu/~zjiang/intro_uc.ppt.

In programming, see time sequence

diagram, see

www.cs.wcupa.edu/~zjiang/intro_TS

.ppt.

Wh t ki d f l ti hi iWh t ki d f l ti hi i


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What kind of relationship isWhat kind of relationship is

generalizationgeneralization

People

Student

x: inty: int

radius: doubleRectangle

PositionPoint

Circle

PositionPoint

*Tip 4: Class A is a super class of class B if and only if anyobject of class B can also play the role as an object of class A.


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H t k th i t fH t k th i t f


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How to keep the consistency ofHow to keep the consistency of

all the constraintsall the constraints

Ticket-buyer Dependent

Traveler

1 0..60..1

csc589 intro oo-object oriented analysis and design

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