object oriented – SAP EWM Help

Types of Inheritance in SAP OOABAP

DPM125 — Thu, 07 Aug 2025 07:37:25 +0000

1. Single Inheritance (Supported in ABAP)

Definition: One subclass inherits from one superclass.
Use: Most common form of inheritance.

CLASS parent_class DEFINITION.
  PUBLIC SECTION.
    METHODS: display.
ENDCLASS.

CLASS parent_class IMPLEMENTATION.
  METHOD display.
    WRITE: 'Parent class method'.
  ENDMETHOD.
ENDCLASS.

CLASS child_class DEFINITION INHERITING FROM parent_class.
ENDCLASS.

CLASS child_class IMPLEMENTATION.
ENDCLASS.

2. Multilevel Inheritance (Supported in ABAP)

Definition: A class inherits from a child class, which itself inherited from a parent class.
Hierarchy: Grandparent → Parent → Child

CLASS grandparent DEFINITION.
  PUBLIC SECTION.
    METHODS: method_gp.
ENDCLASS.

CLASS parent DEFINITION INHERITING FROM grandparent.
  PUBLIC SECTION.
    METHODS: method_p.
ENDCLASS.

CLASS child DEFINITION INHERITING FROM parent.
  PUBLIC SECTION.
    METHODS: method_c.
ENDCLASS.

3. Hierarchical Inheritance (Supported via multilevel in ABAP)

Definition: Similar to multilevel, but describes a tree of inheritance.
ABAP supports this by chaining multiple single inheritances.

4. Multiple Inheritance (❌ Not Supported Directly in ABAP)

Definition: A class inherits from more than one superclass.
ABAP Limitation: ABAP allows a class to inherit from only one class directly.
Alternative: Use interfaces to simulate multiple inheritance.

what are access specifiers in SAP and tell the difference between them and explain their use ?

DPM125 — Mon, 04 Aug 2025 18:30:55 +0000

Access specifiers define the visibility and accessibility of class components such as attributes, methods, and events. They help in implementing encapsulation, a core concept of object-oriented programming (OOP), by controlling which parts of a class can be accessed from outside the class or by its subclasses.

There are three main access specifiers in SAP ABAP:

1. PUBLIC

2. PROTECTED

3. PRIVATE

Steps to Use Access Specifiers in ABAP Classes

1. Create a class using CLASS…ENDCLASS.

2. Define sections for PUBLIC, PROTECTED, and PRIVATE using PUBLIC SECTION, PROTECTED SECTION, PRIVATE SECTION.

3. Place the methods or attributes under the appropriate section based on the intended visibility.

4. Instantiate the class and test accessibility from outside and inside (e.g., subclasses).

Access Specifier Visibility Scope Accessible From Use Case Example

PUBLIC High Anywhere (outside class too) General methods available to all

PROTECTED Medium Inside class + subclasses Internal logic exposed to subclasses only

PRIVATE Low Only inside the class Helper methods/data hidden from outside

Access specifiers in SAP ABAP enable secure and modular class design:

· Use PUBLIC for features meant to be openly accessible.

· Use PROTECTED when you want subclass access but hide from external calls.

· Use PRIVATE to fully encapsulate internal logic or helper routines.

so Outside the class

we cannot call the Private and protected Methods or attributes

What is an Interface in SAP ABAP?

DPM125 — Sun, 03 Aug 2025 06:42:49 +0000

An interface in ABAP defines a contract that any implementing class must follow. It contains only declarations of:

Methods (without implementation)
Constants
Types
Attributes

Interfaces do not contain implementation. Any class that implements an interface must provide the logic for all its methods.

Feature	Description
No implementation	Only method signatures are defined.
Multiple interfaces	A class can implement more than one interface.
Full implementation required	All interface methods must be implemented in the class.
Promotes loose coupling	Ideal for modular, testable, flexible code.

Code:

REPORT zrep_lclclass.

INTERFACE if_animal.
  METHODS:
    speak,
    move.
ENDINTERFACE.

" Class that implements the interface
CLASS lcl_dog DEFINITION.
  PUBLIC SECTION.
    INTERFACES: if_animal.
ENDCLASS.

CLASS lcl_dog IMPLEMENTATION.
  METHOD if_animal~speak.
    WRITE: 'Woof!'.
  ENDMETHOD.

  METHOD if_animal~move.
    WRITE: 'Dog is running'.
  ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.
  DATA(lo_dog) = NEW lcl_dog( ).
  lo_dog->if_animal~speak( ).
  lo_dog->if_animal~move( ).

Output:

What is an Abstract Class in SAP ABAP?

DPM125 — Sun, 03 Aug 2025 06:37:17 +0000

An abstract class is a class that cannot be instantiated directly. It serves as a blueprint for other classes. Abstract classes typically include:

Abstract methods, which are declared but not implemented.
Concrete methods, which can be implemented and inherited.

Feature	Description
Not instantiable	Cannot use `CREATE OBJECT` on abstract classes.
Used for inheritance	Serve as base classes for child classes.
Can contain abstract methods	These must be implemented in subclasses.
Can contain concrete methods	These can be used directly by child classes.

REPORT zrep_lclclass.

CLASS lcl_animal DEFINITION ABSTRACT.
  PUBLIC SECTION.
    METHODS:
      speak ABSTRACT,
      move.         " This can be implemented if needed
ENDCLASS.

CLASS lcl_animal IMPLEMENTATION.
  METHOD move.
    WRITE: 'Animal is moving'.
  ENDMETHOD.
ENDCLASS.

" Concrete subclass
CLASS lcl_dog DEFINITION INHERITING FROM lcl_animal.
  PUBLIC SECTION.
    METHODS:
      speak REDEFINITION.
ENDCLASS.

CLASS lcl_dog IMPLEMENTATION.
  METHOD speak.
    WRITE: 'Woof!'.
  ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.
  " Parent Class
  DATA(lo_animal) = NEW lcl_animal( ).
  lo_animal->speak( ).
  WRITE: 'Animal can speak'.
  SKIP.
  " child class
  DATA(lo_dog) = NEW lcl_dog( ).
  lo_dog->speak( ).
  lo_dog->move( ).

Output:
Check the Program ( CTRL + F2 ).

if not initated the Parent class then the output will be.

Output: