Page 15 - DCAP308_OBJECT_ORIENTED_ANALYSIS_AND_DESIGN

Unit 1: Introduction to Object Orientation

and develop new classes with less effort. Inheritance is one of the main advantages of any object Notes
oriented language, because it gives scope to share basic code.
In a broader way we can say that object oriented development not only allows information
sharing and reuse within an application, but also, it gives a base for project enhancement in
future. As and when there is a need for adding new characteristics in the system, they can be
added as an extension of existing basic features. This can be done by using inheritance and that
too, without major modification in the existing code. But be aware that just by using object
orientation, you do not get a license to ensure reusability and enhancement. For ensuring
reusability and enhancement you have to have a more general design of the system.

Did u know? This type of design can be developed only if the system is properly studied
and features of proposed system are explored.

Task How does sharing of code using inheritance prove to be an advantage of
object oriented languages?

1.3.5 Emphasis on Object Structure, not on Operation Implementation

In object orientation the major emphasis is on specifying the characteristics of the objects in a
system, rather than implementing these characteristics. The uses of an object depend highly on
the facts of the application and regular changes during development. As requirements extend,
the features supplied by an object are much more stable than the ways in which they are used,
hence software systems built on object structure are more secure.
While developing a system using the object oriented approach, main emphasis is on the essential
properties of the objects involved in the system than on the procedure structure to be used for
implementation. During this process what an object is, and its role in system is deeply thought
about.

Self Assessment

Fill in the blanks:
11. ...................... consists of focusing on the essential, inherent aspects of an entity and ignoring
its accidental aspects.
12. The process of encapsulation is also known as ......................
13. Inheritance of both data structure and behavior allows common structure to be shared
among several similar subclasses without ......................

1.4 Evidence for Usefulness of OO Development

Object oriented development began at the General Electric Research and Development Center.
We used object oriented technologies for developing compilers, graphics, user interfaces,
databases, an object oriented language, CAD systems, simulations, meta models, control systems,
and other applications. We used object oriented models to document programs that are
ill-structured and difficult to understand. Our implementation targets ranged from object oriented
languages to non object-oriented languages to databases. We successfully taught this approach
to others and used it to communicate with application experts.

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