Week1 IntroToOO

8/7/2019 Week1 IntroToOO

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Introduction to Object Orientation


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Objectives: Introduction to Object Orientation

Understand the basic principles of object orientationUnderstand the basic principles of object orientation

Define the basic concepts and terms of object orientationDefine the basic concepts and terms of object orientation

Discuss the strengths of object orientationDiscuss the strengths of object orientation


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Introduction to Object Orientation Topics

Basic Principles of Object OrientationBasic Principles of Object Orientation

Basic Concepts of Object OrientationBasic Concepts of Object Orientation


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Basic Principles of Object Orientation

Object Orientation

Enc

apsulation

Ab

straction

H

ierarchy

M

odularity


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What is Abstraction?

Customer

Salesperson

Product


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What is Encapsulation?

Hide implementation from clientsHide implementation from clients

Clients depend on interface


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What is Modularity?

The breaking up of something complex into manageableThe breaking up of something complex into manageablepiecespieces

Order Processing

System

Billing

OrderEntry

Order

Fulfillment


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What is Hierarchy?

Decreasing

abstraction

Increasing

abstraction

Asset

RealEstate

Savings

BankAccount

Checking Stock

Security

Bond

Classes at the same level of the hierarchyshould be at the same level of abstraction

Levels of abstractionLevels of abstraction


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Basic Concepts of Object Orientation

ObjectObject

ClassClass

AttributeAttribute OperationOperation

ComponentComponent

GeneralizationGeneralization

PolymorphismPolymorphism


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What is an Object?

BehaviorBehavior

StateState

Unique identityUnique identityEnglish 101

Geology 110

Geology 110World History 200

Algebra 110Music History 200

Intro to OO 180


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What is a Class?

An object is defined by a classAn object is defined by a class

English 101

Geology 110

Geology 110World History 200

Algebra 110Music History 200

Intro to OO 180

CourseOffering


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What is an Attribute?

:CourseOffering

number = 101

startTime = 900

endTime = 1100

:CourseOffering

Name = 104

startTime = 1300endTime = 1500

CourseOffering

number

startTime

endTime

Class

Attribute

Object

Attribute Value


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What is an Operation?

CourseOffering

addStudent

deleteStudent

getStartTime

getEndTime

Class

Operation


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A nonA non--trivial, nearly independent, and replaceable part of atrivial, nearly independent, and replaceable part of asystem that fulfills a clear function in the context of a wellsystem that fulfills a clear function in the context of a well--defined architecturedefined architecture

Component Name

Component

Name

What Is A Component?

Design Model Implementation Model

Component

Interface

Component

Interface


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What is Generalization?

One class inherits from anotherOne class inherits from another

Truck

tonnage

GroundVehicle

weight

licenseNumber

Car

owner

register( )

getTax( )

Person

0..*

Trailer

1

ancestor

decendent

generalization

size


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What is Polymorphism?

The ability to hide many different implementations behind aThe ability to hide many different implementations behind asingle interfacesingle interface

Manufactor AManufactor A

Manufactor C


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Strengths of Object Orientation

A single paradigmA single paradigm

Single language used by users, analysts, designers,implementers

Facilitates architectural and code reuseFacilitates architectural and code reuse

Models more closely reflect the real worldModels more closely reflect the real world

More accurately describe corporate data and processes Decomposed based on natural partitioning

Easier to understand and maintain

StabilityStabilityA small change in requirements does not mean massive

changes in the system under development


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A Simple Sales Order Example

Order

Product

Ship via


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Class Diagram for the Sales Example

Salesperson Product

Sale

Corporate

Customer

Individual Truck

Vehicle

Train


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Review: Introduction to Object Orientation

What are the four basic principles of object orientation?What are the four basic principles of object orientation?Provide a brief description of each.Provide a brief description of each.

What is an Object and what is a Class? What is theWhat is an Object and what is a Class? What is thedifference between them?difference between them?

What is an Attribute?What is an Attribute?

What is an Operation?What is an Operation? What is generalization?What is generalization?

What is polymorphism?What is polymorphism?

Describe the strengths of object orientation.Describe the strengths of object orientation.

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Week1 IntroToOO