object oriented concepts

[Former Member]

Hi Gurus,

I want to know thw difference between objectoriented program and abap general programme?

thanks in advance

[Former Member]

Hi Rama Krishna ,

Object Orientation

A programming technique in which solutions reflect real world objects

What are objects ?

An object is an instantiation of a class. E.g. If “Animal” is a class, A cat

can be an object of that class .

With respect to code, Object refers to a set of services ( methods /

attributes ) and can contain data

What are classes ?

A class defines the properties of an object. A class can be instantiated

as many number of times

Advantages of Object Orientated approach

Easier to understand when the system is complex

Easy to make changes

Encapsulation - Can restrict the visibility of the data ( Restrict the access to the data )

Polymorphism - Identically named methods behave differently in different classes

Inheritance - You can use an existing class to define a new class

Polymorphism and inheritance lead to code reuse

Classes in abap

Classes in ABAP are either local or global

Global classes are declared in class builder (SE24 )

Local classes are declared within programs

Components of a class

Attributes : Internal data fields of class

Attributes can be either instance attributes – specific to each instance of the class ( object ) or static attributes which are common to all instances

Methods :

Subroutines / procedures in a class that define the behavior of the object. Methods can also be instance methods or static methods

Encapsulation in ABAP

Encapsulation is obtained through the restriction in visibility of attributes / methods attained through the definition of Public, Private and Protected section of a class

Public Section

All of the components declared in the public section are accessible to all users of the class, and to the methods of the class and any classes that inherit from it. The public components of the class form the interface between the class and its users.

Protected Section

All of the components declared in the protected section are accessible to all methods of the class and of classes that inherit from it.

Private Section

Components that you declare in the private section are only visible in the methods of the same class.

Inheritance in ABAP

Inheritance allows you to derive a class based on an already existing class.

CLASS <subclass> DEFINITION INHERITING FROM <superclass>.

…..

ENDCLASS.

CLASS <subclass> IMPLEMENTATION.

……

ENDCLASS.

All attributes / methods of super class become the property of the subclass too. Only public and protected attributes / methods are visible in the subclass

Polymorphism in ABAP

When methods with same name perform differently under different

circumstances we call it polymorphism.

Methods redefined in a subclass is an example for Polymorphism

Interfaces

Interfaces are used to define the model of a class.

They also like classes can be either local or global.

Global interfaces are defined through SE24 and local interfaces are defined in program.

Please check this online document (starting page 1291).

http://help.sap.com/printdocu/core/Print46c/en/data/pdf/BCABA/BCABA.pdf

Also check this links as well.

http://help.sap.com/saphelp_nw2004s/helpdata/en/ce/b518b6513611d194a50000e8353423/frameset.htm

http://www.sapgenie.com/abap/OO/

http://www.futureobjects.de/content/intro_oo_e.html

http://www.sap-img.com/abap/business-add-in-you-need-to-understand-abap-oo-interface-concept.htm

/people/ravikumar.allampallam/blog/2005/02/11/abap-oo-in-action

check the below links lot of info and examples r there

http://www.sapgenie.com/abap/OO/index.htm

http://www.geocities.com/victorav15/sapr3/abap_ood.html

http://www.brabandt.de/html/abap_oo.html

Check this cool weblog:

/people/thomas.jung3/blog/2004/12/08/abap-persistent-classes-coding-without-sql

/people/thomas.jung3/blog/2004/12/08/abap-persistent-classes-coding-without-sql

Hope this resolves your query.

Reward all the helpful answers.

Thanks & Regards

Bhaskar rao.M

[Former Member]

Normal report adn Dialogue programs are event driven whereas the object oriented programming is based on OOPS principles of Data hiding and encapsulation, inheritance, polymorphism