Object Oriented Development

Running head : Object Oriented Development

Object Oriented Development

22nd august 2007

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Table of Contents

TOC \o "1-3 " \h \z \u HYPERLINK \l "_Toc9 " Chapter 1 Introduction PAGEREF _Toc9 \h 3

HYPERLINK \l "_Toc0 " Chapter 2 : What is OOD ? PAGEREF _Toc0 \h 5

HYPERLINK \l "_Toc1 " Chapter 3 : How does OOD help organizations in software development environment ? PAGEREF _Toc1 \h 9

HYPERLINK \l "_Toc2 " Chapter 4 : Merits and Demerits of OOD PAGEREF _Toc2 \h 12

HYPERLINK

\l "_Toc3 " Conclusion : PAGEREF _Toc3 \h 15

HYPERLINK \l "_Toc4 " Bibliography PAGEREF _Toc4 \h 16

Chapter 1 : Introduction

The `Object Oriented Development ' consists of progressively developing a software application which would form a real world model of the business scenario . It gives a true picture of the real world entities and the association among them . It makes it quite understandable and readable in nature

Unlike the traditional software development environment , it portrays the real world instances of the atmosphere in connection to all the related internal and external entities

The sections of this would outline and discuss the various process flow of the object oriented development environment and the phases that make it different from the other process models . The appropriate breakdown of the entire life cycle phase would make it acceptable and would provide a bird 's eye view to the entire process flow

The next section would highlight the various techniques the system analyst 's use for modeling their processes . The use of Use cases , class diagrams , state diagram , activity diagram , sequence diagrams and many more would be explained for their importance and relevance in depicting the business scenario

Finally the merits and demerits of the technology are elaborated and discussed quite vividly . The amount of positive feedbacks it obtains along with the negative ones makes it quite well judged in the light of other software development paradigms

The conclusion takes care of the future of OOD and the better technologies which are posing a challenge

Chapter 2 : What is OOD

Object Oriented Development (OOD ) is the superb ability to represent complex relationships as well as to represent data and data processing with a consistent notation so that it is easily amendable at the analysis and design phase (Hoffer . 2002

The depiction of OOD is made with the help of diagrams which depict the business scenario and the very objective of the software to be built The association of the various objects and their interaction is depicted with the help of those diagrams . Unlike the other software development paradigms , OOD makes sure that the dynamism in the behavior of the associated entities and the processes which they would be subjected to would be depicted quite distinctly in nature so that it gets a whole new meaning to the design phase

The various features of the OOD which makes the development environment distinguishable are the following

Abstraction

The entire concept of abstraction is hiding the view and access of data from the outside world so that it does not face accidental or intentional alteration . The program data and elements are hidden from outside access so that the user has no role to play in either viewing it or changing them to get desirable results . This feature makes the OOD process unique to other development strategies

Encapsulation

The wrapping up of data and functions into a single unit called class is termed as encapsulation . It provides the mechanism of holding the program elements so that instances can be drawn easily and we can work better . OOD makes it quite feasible to envelope all the associated information of an entity into one single unit called the class

Inheritance and Reusability

Inheriting the traits of the parent entity , so that the child does not require redefining all the common characteristics is known as Inheritance . The reusability factor would make fewer codes to be written and existing codes to be used

Polymorphism

The entire concept of polymorphism is the ability to take another form The existing objects can be used for various functionalities which makes it quite distinct than the other forms of development strategies

Characteristics of OOD

Object-oriented analysis , design and programming are related but distinct

OOA is concerned with developing an object model of the application domain

OOD is concerned with developing an object oriented system model to implement requirements

OOP is concerned with realizing an OOD using an OO programming language such as Java or C

Objects are abstractions of real-world or system entities and manage themselves

Objects are independent and encapsulate state and representation information

System functionality is expressed in terms of object services

Shared data areas are eliminated . Objects communicate by message passing

Objects may be distributed and may execute sequentially or in parallel

The magic of the different types of diagrams makes the depiction quite vibrant in nature . The following are some of those

UML : Unified Modeling Language is a language for specifying , visualizing and constructing the artifacts of software systems , as well as for business modeling (UML Document Set , 1995 . The Use case diagram takes the form of such a modeling language

Figure SEQ Figure \ ARABIC 1 : UML Class diagram

Sequence Diagrams : It depicts the of interactions which takes place among the objects . Objects are arranged horizontally across the top Time is represented vertically so models are read top to bottom Interactions are represented by labeled arrows , Different styles of arrow represent different types of interaction A thin rectangle in an object lifeline represents the time when the object is the controlling object in the system

Figure SEQ Figure \ ARABIC 2 : Sequence Diagram

State Chart : It shows the process of response of objects different service requests and the state transitions triggered by these requests If object state happens to be Shutdown then it responds to a Startup message In the waiting state the object is waiting for further messages If reportWeather ) then system moves to summarizing state If calibrate ) the system moves to a calibrating state A collecting state is entered when a clock signal is received (See www .comp .lancs .ac .uk /computing /resources /IanS /SE7 /Presentations /PDF /ch14 .pdf

Figure SEQ Figure \ ARABIC 3 : State Diagram

Chapter 3 : How does OOD help organizations in software development environment

OOD stands quite ideal for representing the real world scenario which would most appropriately be interpreted by all levels of people in the software development team and also the requirements can be mapped distinctly to represent the business situation . The process to be followed is defined in the coming sections which make the development atmosphere quite distinct

The following are the development phases which are undertaken when the software passes through the developmental phases to develop into a deliverable (See Figure 1

In the OOD analysis phase , a model of the real-world application is developed showing its essential properties . It abstracts concepts from the application domain and describes what the intended system must do rather than how it will be done

Figure SEQ Figure \ ARABIC 4 : OOD Cycle

The model specifies the functional behavior of the system

In the OOD design phase , the definition as to the `how ' the application-oriented analysis model will be realized in the implementation environment . It requires identification and investigation of the consequences the implementation environment will have on the design (Pressman , 2003 . All strategic decisions such as how the DBMS is to be incorporated , how process communications and error handling are to be achieved and what component libraries are to be reused-are made These decisions are incorporated into a first- cut design model that adapts the implementation environment . Finally the formalization is done to describe the interaction between the objects

Implementation of the OOD would be in programming languages which supports all the features of the OOPS concepts and methods . The database also would be designed in the similar manner so as to keep in synchronization with the front end interface

The reason as to which the OOD must be favored by any organisation are as follows

Unlike other paradigms or models where the analysis model is directly implemented with the programming language . OOD moves seemingly into the source code after refining the objects and making prior decisions on what operations an object will provide . The inter-object communication is well defined in OOD which clearly depicts the messages to be passed and so forth

The actual system must be adapted to the environment in which the system will actually be implemented . To accomplish that , the analysis model has to be transformed into a design model , considering the other factors

The OOD analysis results can be validated using object-oriented design At this stage , the results are verifiable with the analysis model

The greater understanding and skill in operation steps would make the process to be monitored evenly so that everything is done rightly in the first instance

Chapter 4 : Merits and Demerits of OOD

Object Oriented Design (OOD ) methodologies primarily have two key strengths . First , they do an excellent job of supporting COTS and reuse (Rickman , 2000 . OOD is basically a bottom up approach where you are able to view the system as a set of objects that can be departmentalized to form a system . The OOD approach inherently makes software 's object a stand alone component that can be reused with a variety of problem domains thus providing the unexplored problem complexity into a feasible state for analysis and development

Coad and Yourdon (1991 ) identifies the merits of the OOD paradigm to be as follows

The ability to tackle more challenging problem domains

Improved communication among users , analysts , designers and programmers

Increased consistency among analysis , design and programming activities

Explicit representation of commonality among system components

Robustness of systems

Reusability of analysis , design and programming results

Increased consistency among all the models developed during object-oriented analysis , design and programming

Easier maintenance . Objects can be understood as stand alone entities

Provides an insight into data relationships and associations

The demerits of OOD are as follows

Lack of a System Functional Model

The OOD only creates functional model within the objects and not the entire system . This is the biggest drawback of the OOD where it has equal opportunity to miss some crucial requirements in the design process

System performance and sizing is difficult

The OOD model does not easily describe the associations and communications between objects . However , the basic concept of OOD is that the object need not know who is invoking it and how the messages are exchanged . While this leads to a flexible design , performance modeling cannot be handled readily

Identification objects is week

The OOD methodology by itself does not provide support for identifying which objects will generate an optimal system design . Specifically there is no single diagram that shows all of the interfaces between objects . Since coupling is a major factor in system complexity , not having this information makes architecture component selection a hit or miss proposition (Rickman , 2000

Conclusion

OOD would make the system development strategy makes a great and sound impact to the development paradigms . It makes it quite real to the prevailing conditions of the business scenario which would be analyzed and designed to develop the system

The very use of the different diagrams discussed makes the system and illustration more generalized in nature and easily makes it able to model . The various diagrams are for different problem domains and representing the situation according to the prevailing conditions References / Bibliography

Coad ,

, and E . Yourdon (1991 . Object-Oriented Design

Englewood Cliffs , NJ : Prentice hall

Booch , G (1994 . Object-Oriented analysis and Design with

Application . 2nd Ed . Redwood City , CA

Hoffer A . Jeffery (2002 . Modern Systems Analysis and Design

Pearson Education

Jacobson , I (1992 . Object-Oriented Software Engineering : A use

case driven approach , Addison-Wesley

Silvia , T Acu (2000 . A Process model applicable to Software

engineering and knowledge Engineering

Sommerville , Ian (2003 . Software Engineering . Pearson

Education , 2004

UML Document Set (1997 . Santa Clara : Rational Software

Corporation

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