Subject: Object Oriented Modeling and Design

Difficulty: Medium

Marks: 4 Marks

• Abstraction
• Encapsulation
• Combining Data& behaviour
• Sharing
• Emphasis on the essence of object
• Synergy

1) Abstraction:

• It means focusing on the essential aspects of an entity while ignoring its details.

• This means focusing on what an object is and does, before deciding how it should be implemented.

• Use of abstraction during analysis means dealing only with application domain concepts, not making decisions before problem is understood.

2) Encapsulation:

• It means information hiding. It consists of separating the external aspects of an object, which are accessible to other objects, from internal implementation details of the object, which are hidden from other objects.

• It prevents program from becoming so interdependent that a small change has massive ripple effect. It gives the ability to combine data structure and behaviour in a single entity.

3) Combining Data and Behavior:

• The burden of calling code for data execution and operations separately can be minimized by combining data properties and behavioural properties of an entity together.

• In object oriented program data structure and procedure is defined in single class definition.

4) Sharing:

• Object Oriented technologies promote sharing at different levels. Inheritance of both data structure and behavior lets subclasses share common code.
• This sharing via inheritance is one of the main advantages of Object Oriented languages.
• Object Oriented Development not only lets you share information within an application but also offers the prospect of reusing designs and code on future projects.

5) Emphasis on the essence of object:

• Object Oriented Technology stresses what an object is, rather than how it is used.

• The uses of an object depend on the details of the application and often change during development.

6. Synergy:

• Identity, classification, polymorphism and inheritance characterize Object Oriented languages.

• Each of these concepts can be used in isolation but together they complement each other synergistically.