Object Oriented Systems Development Prachet Bhuyan Assistant Professor, School of Computer & Information Science & Technology, KIIT University.

AN OVERVIEW OF OBJECT ORIENTED SYSTEMS DEVELOPMENT CHAPTER - 1

1.1 Introduction Software development is dynamic and always undergoes major changes. Vast number of Tools & Methodologies are available for systems development. Systems Development refers to all activities that goes into producing an information systems solution.

1.1 Introduction (contd….) Systems development consists of: Analysis Design Modeling Implementation Testing & Maintenance

1.1 Introduction (contd….) A Software development methodology is a series of processes that, if followed can lead to the development of an application. Unified Approach is the methodology used by Dr. Ali Bahrami for learning OOSD.

1.2 Two Orthogonal Views of the Software OOSD Methodology: Views software in the form of objects which are discrete and grouped. OOSD focuses on the object, which combines data and functionality Primary focus is on data. Data security is given utmost attention.

1.2 Two Orthogonal Views of the Software (contd….) Traditional Development Technique: Views software as collection of programs or functions and isolated data. Algorithm + Data Structure = Program It focuses on the functions of the system – What is it doing ? Primary focus is on function. Data is free flowing.

1.3 OOSD Methodology OOSD is a way to develop software by building self-contained modules or objects that can be easily replaced, modified and reused. OOSD encourages views of the world as a system of cooperative and collaborating objects.

1.3 OOSD Methodology (contd….) In an O-O environment software is a collection of discrete objects that encapsulate their data as well as the functionality, to model real-world entity. In an O-O system everything is an object and each object is responsible for itself.

1.4 Why an Object Orientation ? O-O systems are : Easier to adapt to changing requirements Easier to maintain More robust & promote greater design & Code reuse

1.4 Why an Object Orientation ? (contd….) Reasons why object orientation works: Higher level of abstraction. (At object level) Seamless transition among different phases of software development. O-O uses same language like UML(Unified Modeling Language) to talk about all phases of software development. It reduces complexity, redundancy, & creating a robust system. Encouragement of good programming technique. & Promotion of reusability.

1.5 Overview of the UNIFIED APPROACH The Unified Approach(UA) is a methodology for software development that is proposed by the author Dr. Ali Bahrami. (and used in this book of OOSD) The UA is based on methodologies by Grady Booch, Rumbaugh & Ivar Jacobson, tries to combine the best practices, processes & guidelines along with OMG’s (Object Management Group’s) UML.

1.5 Overview of the UNIFIED APPROACH (contd….) The heart of UA is Jacobson’s use-case. Use case represents a typical interaction between a user and a computer system to capture the user’s goals and needs. This book of OOSD uses a Layered Architecture(LA) to develop applications.

1.5 Overview of the UNIFIED APPROACH (contd….) LA is an approach to software development that allows us to 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. Layered Approach consists of: View or UI (User Interfaces) Layer Business Layer Access Layer

Goals for OOSD The software development process Building high-quality software Object-oriented systems development Use-case driven systems development Prototyping

Summary The OOSD is an iterative process and is divided into analysis, design, prototyping/implementation, and testing. The UA, Layered Architecure & UML is used by Dr. Ali Bahrami for OOSD. (Reference: Object-Oriented Systems Development by Ali Bahrami, Tata McGraw-Hill, 2008)

The Journey of OOSD begins....