New To OOPs ABAP

Object orientation (OO), or to be more precise, object-oriented programming, is a problem-solving method in which the software solution reflects objects in the real world.

A comprehensive introduction to object orientation as a whole would go far beyond the limits of this introduction to ABAP Objects. This documentation introduces a selection of terms that are used universally in object orientation and also occur in ABAP Objects. In subsequent sections, it goes on to discuss in more detail how these terms are used in ABAP Objects. The end of this section contains a list of further reading, with a selection of titles about object orientation.

Uses of Object Orientation

Below are some of the advantages of object-oriented programming:

Complex software systems become easier to understand, since object-oriented structuring provides a closer representation of reality than other programming techniques.

In a well-designed object-oriented system, it should be possible to implement changes at class level, without having to make alterations at other points in the system. This reduces the overall amount of maintenance required.

Through polymorphism and inheritance, object-oriented programming allows 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.

Achieving these goals requires:

Object-oriented programming languages

Object-oriented programming techniques do not necessarily depend on object-oriented programming languages. However, the efficiency of object-oriented programming depends directly on how object-oriented language techniques are implemented in the system kernel.

Object-oriented tools

Object-oriented tools allow you to create object-oriented programs in object-oriented languages. They allow you to model and store development objects and the relationships between them.

Object-oriented modeling

The object-orientation modeling of a software system is the most important, most time-consuming, and most difficult requirement for attaining the above goals. Object-oriented design involves more than just object-oriented programming, and provides logical advantages that are independent of the actual implementation.

This section of the ABAP User’s Guide provides an overview of the object-oriented extension of the ABAP language. We have used simple examples to demonstrate how to use the new features. However, these are not intended to be a model for object-oriented design. More detailed information about each of the ABAP Objects statements is contained in the keyword documentation in the ABAP Editor. For a comprehensive introduction to object-oriented software development, you should read one or more of the titles listed below.

At the center of any object-oriented model are objects, which contain attributes (data) and methods (functions). Objects should enable programmers to map a real problem and its proposed software solution on a one-to-one basis. Typical objects in a business environment are, for example, ‘customer’, ‘Order’, or ‘Invoice’. From Release 3.1 onwards, the Business Object Repository (BOR) has contained examples of such objects. The object model of ABAP Objects, the object-oriented extension of ABAP, is compatible with the object model of the BOR.

Before R/3 Release 4.0, the nearest equivalent of objects in ABAP were function modules and function groups. Suppose we have a function group for processing orders. The attributes of an order correspond to the global data of the function group, while the individual function modules represent actions that manipulate that data (methods). This means that the actual order data is encapsulated in the function group, and is never directly addressed, but instead only through the function modules. In this way, the function modules can ensure that the data is consistent.

When you run an ABAP program, the system starts a new internal session. The internal session has a memory area that contains the ABAP program and its associated data. When you call a function module, an instance of its function group plus its data, is loaded into the memory area of the internal session. An ABAP program can load several instances by calling function modules from different function groups.

The instance of a function group in the memory area of the internal session almost represents an object in the sense of object orientation

When you call a function module, the calling program uses the instance of a function group, based on its description in the Function Builder. The program cannot access the data in the function group directly, but only through the function module. The function modules and their parameters are the interface between the function group and the user.

The main difference between real object orientation and function groups is that although a program can work with the instances of several function groups at the same time, it cannot work with several instances of a single function group. Suppose a program wanted to use several independent counters, or process several orders at the same time. In this case, you would have to adapt the function group to include instance administration, for example, by using numbers to differentiate between the instances.

In practice, this is very awkward. Consequently, the data is usually stored in the calling program, and the function modules are called to work with it (structured programming). One problem is, for example, that all users of the function module must use the same data structures as the function group itself. Changing the internal data structure of a function group affects many users, and it is often difficult to predict the implications. The only way to avoid this is to rely heavily on interfaces and a technique that guarantees that the internal structures of instances will remain hidden, allowing you to change them later without causing any problems.

This requirement is met by object orientation. ABAP Objects allows you to define data and functions in classes instead of function groups. Using classes, an ABAP program can work with any number of instances (objects) based on the same template.

Instead of loading a single instance of a function group into memory implicitly when a function module is called, the ABAP program can now generate the instances of classes explicitly using the new ABAP statement CREATE OBJECT. The individual instances represent unique objects. You address these using object references. The object references allow the ABAP program to access the interfaces of the instances.

The following sections contain more information about classes, objects, interfaces, and object references in ABAP Objects.

reward points if helpful............

Former Member · ‎10-04-2007

hI

Look at:

ABAP Trial Version for Newbies: Part 17 - Your first ABAP Object

ABAP Code Sample for Objects

Object Oriented ABAP - Local and Global classes

ABAP Code Sample to Learn Basic Concept of Object-Oriented Programming

Eight Reasons Why Every ABAP Developer Should Give ABAP Objects a Second Look

Why use ABAP Objects

ABAP Objects for Java Developers

<b>REWARD IF USEFULL</b>

Former Member · ‎10-04-2007

HI

UNDERSTAND THIS DIFF

https://www.sdn.sap.com/irj/sdn/wiki?path=/display/profile/2007/07/09/understandingABAPObjects&

REWARD IF USEFULL

Former Member · ‎10-06-2007

Check this link.

http://help.sap.com/saphelp_nw2004s/helpdata/en/fc/eb3530358411d1829f0000e829fbfe/frameset.htm

Former Member · ‎10-08-2007

Hi,

The following lines explain the main Abap object oriented concepts that differs from traditional abap.

I have explained object orientation which is such an important aspect in SAP. The discussion began with the features of Object Orientation and includes the runtime environment, the language extension, the classes and the class components. Apart from that I have also discussed for new first time readers event handling, inheritance encapsulation and polymorphism.

Regards,

Padmam.