Monday, 30 April 2012

Object Orientation

Object Orientation (OO) or Object Oriented Programming is a PROBLEM-SOLVING method in which the software solution reflects Objects in Real World

Class
A section of source Code that contains Data and Provides services into a single Unit.
Data forms the Attributes.
Services are known as methods. Typically methods operate upon Private data (attributes or the state of the object), which is only visible to the methods of the class
Attributes cant be changed directly by the user, but by the methods of the class.


Encapsulation
The Implementation of object is encapsulated that is invisible outside the object itself.

Polymorphism
Identically named methods behave differently in different classes, i.e the implementation of the method is specific to a particular class.

Inheritance
A new class can be derived from an existing class. The new class is a child class and the existing class is a parent class. The new class or the derived class inherit the data and methods of the super class, However we can overwrite the inherited methods using Redefinition.


Uses of Object Orientation

  • Complex Software systems become easier to understand
  • Polymorphism and Inheritance allow you to reuse individual components
  • In an object oriented system the amount of work involved in revising and maintaining the system is reduced, since many problems can be detected and corrected in the design Phase
ABAP Objects
 It is a new concept in R/3 Release 4.0
The term has 2 meanings, It stands for the entire ABAP Runtime and also represents the Object oriented extension of ABAP Language

Structure of a Class
The following statements define the structure of a Class

  • A class contains Components
  • Each component is assigned to a visibility Section
  • Classes implements Methods
Components of a Class
There are 2 kinds of components in a class- those that exist separately for each object in the class and those that exist only once for the whole class, regardless of the number of instances. Instance specific components are known as Instance components. Components that are not instance-specific are called Static Components


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