Chap-1 Rkm Intro

8/18/2019 Chap-1 Rkm Intro

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CHAP-1CHAP-1

OBJECT ORIENTEDOBJECT ORIENTED

SYSTEM DESIGNSYSTEM DESIGN

(IT-703)(IT-703)

Text BooksText Books1! Object Oriented System Development

Ali Bahrami (TMH)"! Object-Oriented Modeling Design !ith "M#

Blaha $amba%gh (&earson)3! Object-Oriented Analysis Design %sing "M#

D 'eya Mala S eetha(TMH)#! Object-Oriented Analysis Design and *mplementation

Brahma Dathan Sarnath $amnath ("niversity &ress)

OOSD- *ntrod%ction +


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An overview of

object-Oriented

Systems Development

,OOSD- *ntrod%ction


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Q. What major problems have you encountered during past

software projects?

o Project estimation (under estimation)

o Time effort estimation

o Premature implementation

o Quic! prototyping the problem

o "eeling of understanding problem but really not

o #hanging re$uirements

(Waterfall model

%ncremental model

&volutionary development model

'gile model)

OOSD- *ntrod%ction


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IntroductionIntroduction oftware development is dynamic

*. 'lways undergoes major changes+. #urrent and future practice will be different,. 'nticipate the methods and tools to succeed-. #an not predict the future

Today vast number of tools and methodologies areavailable for systems development.

ystem development activity consists ofystems analysis

modelingdesign

testing

implementation and

maintenance..OOSD- *ntrod%ction


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' software (W) development methodology is a series of

processes if followed can lead to the development of anapplication.

&ach process consists of number of steps and rules to

be followed during development.

nified 'pproach is the methodology used

by /r. 'li 0ahrami for learning 11/.

/OOSD- *ntrod%ction


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Two 1rthogonal views of the WTwo 1rthogonal views of the W

1bject21riented systems development differs from

Traditional development techni$ues. Traditionaltechni$ue view the W as a collection of programs (or

functions) and isolated data.

What is a program? 3i!laus Writh inventor of Pascal sums it up

Algorithm + Data Structure = Program

' W system is a set of mechanism for performing

certain action on certain data There are two different ways to view software

constructions either on functions or on data

OOSD- *ntrod%ction 0


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/ata centered 2 data store (e.g. file or database) lies at the

center of this architecture and is accessed fre$uently by other

components that modify data


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/ata flow 2 input data is transformed by a series of

computational or manipulative components into output data


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1bject2oriented 2 components of system encapsulate data and

operations communication between components is by message

passing

4ayered 2 several layers are defined each accomplishing

operations that progressively become closer to the machineinstruction set


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The distinction between Traditional system developmentmethodologies and newer 1bject2oriented methodologies lies intheir primary focus.

*. Traditional approach focuses on the functions of the system

5 What is it doing ?

+. /ata is free flowing.

11/ 6ethodology71bject2oriented system development centers on the

object.

*.8iews software in the form of objects which are discreteand grouped.

+.11/ focuses on the object which combines data andfunctionality

,. Primary focus is on data.

-. /ata security is given utmost attention.

OOSD- *ntrod%ction +1


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11/ 6ethodology11/ 6ethodology

11/ is a way to develop software by building self2

contained modules or objects that can be easilyreplaced modified and reused.

11/ encourages views of the world as a system of

cooperative and collaborating objects. (e.g. Window)

%n an 121 environment software is a collection ofdiscrete objects that encapsulate their data as well as

the functionality to model real2world entity.

%n an 121 system everything is an object and each

object is responsible for itself .

OOSD- *ntrod%ction ++

/on9t say :system is computing the payroll of employee; you tell the

employee object : compute your payroll;.


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Object Orientation isappropriate

To develop comple2 systems

Systems that are prone to change

Systems !ith %ser inter3aces

Systems that are based on client4servermodel

To b%ild e-commerce 4 !eb based

applications 5or enterprise application integration

(6A*)

OOSD- *ntrod%ction +


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1verview of the nified 'pproach1verview of the nified 'pproachThe nified 'pproach (') is a methodology forsoftware development that is proposed by the author

/r. 'li 0ahrami. (and used in this boo! of 11/)

The ' is based on methodologies by rady 0ooch@ames


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4ayered 'rchitecture (4')4ayered 'rchitecture (4')

4' is an approach to software development that allows usto create objects that represents tangible elements of the

business independent of how they are represented to the

user through an interface or physically stored in a database.

4ayered 'pproach consists of7

i. 8iew or % (ser %nterfaces) 4ayer

ii. 0usiness 4ayer

iii. 'ccess 4ayer



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The nified 'pproach ioms+. /evelop a simple to design classes

business model C. /esign the access

,. /evelop use case layer

-. %nteraction diagram D. /esign view layer

/evelop se$uence diagrams classes

/evelop collaboration diagram 6acro level % design

E. #lassification 6icro level % design

%dentify classes sability and user satisfaction

%dentify relationships


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oals for 11/oals for 11/

The so3t!are development process

B%ilding high-8%ality so3t!are

Object-oriented systems development"se-case driven systems development

&rototyping



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'dvantages of 11/ 'dvantages of 11/

#ode and design reuse

%ncreased productivity

&ase of testing (?) and maintenance

0etter understandability

&legant design7

5 4oosely coupled highly cohesive objects

5 &ssential for solving large problems.

OOSD- *ntrod%ction +:


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%nitially incurs higher costs

5

'fter completion of some projects reduction in costbecome possible

sing well2established 11 methodology and

environment7

5 Projects can be managed with +FG to EFG of

traditional cost of development.

OOSD- *ntrod%ction ,1


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ummaryummary

The 11/ is an iterative process and is divided into

analysis design prototypingHimplementation and

testing.

The ' 4ayered 'rchitecture and 64 are used by

/r. 'li 0ahrami for 11/.

OOSD- *ntrod%ction ,+

Documents

Chap-1 Rkm Intro