OO ABAP – SAP EWM Help

Pillar of OOP program

DPM125 — Thu, 25 Sep 2025 19:35:59 +0000

*&———————————————————————*
*& Report ZCLASS_TEST_DP_1
*&
*&———————————————————————*
*&
*&
*&———————————————————————*

REPORT zclass_test_dp_1.

*pillars of oop

” abstraction –> hiding the data.

” encapsulation –> variable + methods. –> capsule -> 1 + 1 ==
” inheritance –> parent child relation.
” –> child calss will inherit the property of parent class
” polymorphism
” multiple forms –> 1 method — same name and differe param parent ==> child class but with different paremeters. –> method overriding.
” method overloading is not there –> same 2 same name and different parameters.

PARAMETERS: p_num TYPE i.
DATA: lv_tot TYPE i.

CLASS lcl_main DEFINITION.

PUBLIC SECTION.

METHODS: get_data EXPORTING iv_num TYPE i.
METHODS: set_data IMPORTING ev_num TYPE i.

PROTECTED SECTION.
PRIVATE SECTION.
DATA : lv_num1 TYPE i.
ENDCLASS.

CLASS lcl_main IMPLEMENTATION.

METHOD set_data.
lv_num1 = ev_num.
ENDMETHOD.

METHOD get_data.
iv_num = lv_num1.
ENDMETHOD.

ENDCLASS.

” inheritance
class lcl_child DEFINITION INHERITING FROM lcl_main.

PUBLIC SECTION.
METHODS: get_data REDEFINITION.
METHODS: set_data REDEFINITION.

PROTECTED SECTION.

PRIVATE SECTION.
data lv_child type i value 4.
ENDCLASS.

class lcl_child IMPLEMENTATION.

method get_Data. ” method overriding
* ev_tot = iv_num + iv_num2.
” child will gor the child methods first then to parent method.
super->get_data( IMPORTING iv_num = iv_num ). ” way to calling the parent method
ENDMETHOD.

method set_Data.
* ev_tot = iv_num + iv_num2.
” child will gor the child methods first then to parent method.
super->set_data( EXPORTING ev_num = ev_num ). ” way to calling the parent method
ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.
DATA(lo_obj) = NEW lcl_main( ).
DATA(lo_obj_child) = NEW lcl_child( ).

lo_obj_child->set_data(
EXPORTING
ev_num = p_num ).
lo_obj_child->get_data(
IMPORTING
iv_num = lv_tot
).

WRITE : lv_tot.

What is CL_GUI_ALV_GRID?

DPM125 — Sun, 14 Sep 2025 20:01:24 +0000

It’s an ABAP OO class that displays data in a grid (table-like format) inside a screen container.
Unlike the simpler CL_SALV_TABLE, this grid is fully interactive and customizable.

Main Features

Editable cells → You can let users change data directly in the grid.
Field catalog → You define which columns to show, their titles, and if they’re editable.
Layout control → Zebra patterns, column widths, key columns, hotspots, etc.
Events → You can react to user actions (e.g., double-click, toolbar buttons, cell value changes).
Container-based → You need a custom control on a dynpro (screen) to host the ALV Grid.

How it Works (Step-by-Step Flow)

Create a Screen (Dynpro)
- Add a Custom Control (like a placeholder on the screen).
- Give it a name, e.g., CC_ALV.
Create Container
- In your program, create an object of class CL_GUI_CUSTOM_CONTAINER linked to CC_ALV.
- This is the “holder” where the ALV will appear.
Create ALV Grid
- Instantiate CL_GUI_ALV_GRID using the container as its parent.
Build Field Catalog
- Define column properties (FIELDNAME, SELTEXT_M, EDIT, etc.).
- Each entry describes how a column is shown in the ALV grid.
Pass Data to ALV
- Call method set_table_for_first_display with your internal table (IT_OUTTAB) and the field catalog.
Display Grid
- The ALV Grid now shows inside the screen.
- Users can scroll, filter, sort, and (if allowed) edit data.

Steps to Implement CL_GUI_ALV_GRID

1. Create a Screen (e.g., Screen 100)

Go to SE80 → your program → create a screen (No. 100).
On the screen, draw a Custom Control (name it CC_ALV).
Add a GUI status (with functions BACK, EXIT, CANCEL).

REPORT z_alv_grid_editable.

************************************************************************
* TYPES & DATA DECLARATIONS
************************************************************************
TYPES: BEGIN OF ty_spfli,
carrid TYPE spfli-carrid,
connid TYPE spfli-connid,
cityfrom TYPE spfli-cityfrom,
cityto TYPE spfli-cityto,
END OF ty_spfli.

DATA: gt_spfli TYPE TABLE OF ty_spfli,
gs_spfli TYPE ty_spfli.

” ALV references
DATA: go_container TYPE REF TO cl_gui_custom_container,
go_alv TYPE REF TO cl_gui_alv_grid.

” Field catalog & layout
DATA: gt_fieldcat TYPE lvc_t_fcat,
gs_fieldcat TYPE lvc_s_fcat,
gs_layout TYPE lvc_s_layo.

************************************************************************
* START-OF-SELECTION
************************************************************************
START-OF-SELECTION.
” Fetch some demo data
SELECT carrid connid cityfrom cityto
FROM spfli
INTO TABLE gt_spfli.

” Call ALV screen
CALL SCREEN 100.

************************************************************************
* MODULES FOR SCREEN 100
************************************************************************
MODULE status_0100 OUTPUT.
SET PF-STATUS ‘MAIN’. ” Create a status MAIN in GUI status

IF go_container IS INITIAL.
” Create container linked to CC_ALV on screen
CREATE OBJECT go_container
EXPORTING container_name = ‘CC_ALV’.

” Create ALV Grid object
CREATE OBJECT go_alv
EXPORTING i_parent = go_container.

” Layout options
gs_layout-zebra = abap_true. ” striped display

” Build field catalog
CLEAR gs_fieldcat.
gs_fieldcat-fieldname = ‘CARRID’.
gs_fieldcat-seltext_m = ‘Carrier ID’.
gs_fieldcat-edit = abap_true. ” Editable
APPEND gs_fieldcat TO gt_fieldcat.

CLEAR gs_fieldcat.
gs_fieldcat-fieldname = ‘CONNID’.
gs_fieldcat-seltext_m = ‘Connection ID’.
gs_fieldcat-edit = abap_true. ” Editable
APPEND gs_fieldcat TO gt_fieldcat.

CLEAR gs_fieldcat.
gs_fieldcat-fieldname = ‘CITYFROM’.
gs_fieldcat-seltext_m = ‘From City’.
gs_fieldcat-edit = abap_true. ” Editable
APPEND gs_fieldcat TO gt_fieldcat.

CLEAR gs_fieldcat.
gs_fieldcat-fieldname = ‘CITYTO’.
gs_fieldcat-seltext_m = ‘To City’.
gs_fieldcat-edit = abap_true. ” Editable
APPEND gs_fieldcat TO gt_fieldcat.

” Display data in ALV
CALL METHOD go_alv->set_table_for_first_display
EXPORTING
is_layout = gs_layout
CHANGING
it_fieldcatalog = gt_fieldcat
it_outtab = gt_spfli.
ENDIF.
ENDMODULE.

************************************************************************
* Handle user commands
************************************************************************
MODULE user_command_0100 INPUT.
CASE sy-ucomm.
WHEN ‘BACK’ OR ‘EXIT’ OR ‘CANCEL’.
LEAVE PROGRAM.
ENDCASE.
ENDMODULE.

Interface Implementation (Multiple Interfaces)

DPM125 — Thu, 07 Aug 2025 07:41:39 +0000

While ABAP classes can’t inherit from multiple classes, they can implement multiple interfaces, achieving interface-based multiple inheritance.

INTERFACE if1.
  METHODS: method1.
ENDINTERFACE.

INTERFACE if2.
  METHODS: method2.
ENDINTERFACE.

CLASS my_class DEFINITION.
  PUBLIC SECTION.
    INTERFACES: if1, if2.
ENDCLASS.

CLASS my_class IMPLEMENTATION.
  METHOD if1~method1.
    WRITE: 'Method1 from IF1'.
  ENDMETHOD.

  METHOD if2~method2.
    WRITE: 'Method2 from IF2'.
  ENDMETHOD.
ENDCLASS.

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:

Constructor in ABAP

DPM125 — Thu, 31 Jul 2025 20:15:51 +0000

A constructor is a special method automatically called when an object is created using CREATE OBJECT or NEW.

Types of Constructors in ABAP

Type	Method Name	Called On	Purpose
Instance Constructor	`CONSTRUCTOR`	When an object is created (`NEW` or `CREATE OBJECT`)	To initialize instance-specific data
Class Constructor	`CLASS_CONSTRUCTOR`	When the class is first used	To initialize class-level (static) data

REPORT zrep_lclclass.

CLASS zcl_demo DEFINITION.
  PUBLIC SECTION.
    METHODS: constructor,               " Instance constructor
             display_instance_value.

    CLASS-METHODS: class_constructor,  " Class constructor
                   display_class_value.

  PRIVATE SECTION.
    DATA: lv_instance_val TYPE string.
    CLASS-DATA: gv_class_val TYPE string.
ENDCLASS.

CLASS zcl_demo IMPLEMENTATION.

  " Instance Constructor
  METHOD constructor.
    lv_instance_val = 'Initialized in CONSTRUCTOR'.
    WRITE: / '>> Instance CONSTRUCTOR called'.
  ENDMETHOD.

  " Class Constructor
  METHOD class_constructor.
    gv_class_val = 'Initialized in CLASS_CONSTRUCTOR'.
    WRITE: / '>> CLASS_CONSTRUCTOR called (only once)'.
  ENDMETHOD.

  METHOD display_instance_value.
    WRITE: / 'Instance value:', lv_instance_val.
  ENDMETHOD.

  METHOD display_class_value.
    WRITE: / 'Class value:', gv_class_val.
  ENDMETHOD.

ENDCLASS.

START-OF-SELECTION.

* Access class method (triggers class constructor first time)
  zcl_demo=>display_class_value( ).

  SKIP.

* Create object (triggers instance constructor)
  DATA(lo_obj1) = NEW zcl_demo( ).
  lo_obj1->display_instance_value( ).

  SKIP.

* Create another object (instance constructor runs again, but not class constructor)
  DATA(lo_obj2) = NEW zcl_demo( ).
  lo_obj2->display_instance_value( ).

  SKIP.

* Access class method again (class constructor NOT triggered again)
  zcl_demo=>display_class_value( ).

Output:

What is Singleton Class ? how to use Singleton class in SAP ABAP ?

DPM125 — Thu, 31 Jul 2025 19:28:18 +0000

A Singleton class is a design pattern that restricts the instantiation of a class to one single object throughout the lifecycle of a program. This is useful when exactly one object is needed to coordinate actions across the system — such as logging, configuration management, or connection handling.

Key Characteristics of Singleton Pattern:

Only one instance of the class exists.
The class controls its own instantiation.
A global access point is provided to access.

*&---------------------------------------------------------------------*
*& Report  ZREP_LCLCLASS
*&
*&---------------------------------------------------------------------*
*&
*&
*&---------------------------------------------------------------------*

REPORT zrep_lclclass.

CLASS lcl_class_singleton DEFINITION CREATE PRIVATE.
  PUBLIC SECTION.
  " to check the instance is created or not.
    CLASS-METHODS: m_factory RETURNING VALUE(r_instance) TYPE REF TO lcl_class_singleton.
  " getter and setter methods
    METHODS : get_attribute RETURNING VALUE(r_attribute) TYPE i,
              set_attribute IMPORTING m_attribute TYPE i.

  PRIVATE SECTION.
*    CLASS-DATA: obj_instance TYPE REF TO lcl_class_singleton.
    DATA gv_attribute TYPE i.
ENDCLASS.

class lcl_class_singleton IMPLEMENTATION.
    method m_factory.
        if r_instance is not BOUND.
            r_instance = new lcl_class_singleton( ).
        endif.
   ENDMETHOD.

   method get_attribute.
       r_Attribute = gv_Attribute.
   ENDMETHOD.

   method set_attribute.
     gv_Attribute =  m_attribute.
   ENDMETHOD.
 ENDCLASS.

 START-OF-SELECTION.
 " create an instance of class
   data(lo_obj) =  lcl_class_singleton=>m_factory( ).
 " set the value for the attribute.
   lo_obj->set_attribute( 10 ).

   " try to create another instace of the class.
    data(lo_obj2) = lcl_class_singleton=>m_factory( ).
   " check the attribute of the new instance
   " it should be same as go_obj as it contains a static attribute
   " get the data and print it.
   write: 'First object attribute value ', lo_obj->get_attribute( ).
   write :/ 'Second object attribute value ', lo_obj2->get_attribute( ).

Output:

What is the difference between static and instance Members in SAP OOABAP ?

DPM125 — Wed, 30 Jul 2025 17:30:46 +0000

Instance Members (Methods & Data)

Belong to individual objects (instances).
Created using DATA and METHODS.
Each object has its own copy of the data.
Accessed using the object reference: lo_obj->method_name.
Useful when each object should maintain its own state.
Destroyed when the object goes out of scope.

Static Members (Methods & Data)

Belong to the class itself, not any particular object.
Created using CLASS-DATA and CLASS-METHODS.
Only one copy exists for the entire class.
Accessed using the class name: zcl_class_name=>method_name.
Useful for shared data, like counters, configuration, or logging.
Exist as long as the class is loaded in memory.

*&---------------------------------------------------------------------*
*& Report  ZREP_LCLCLASS
*&
*&---------------------------------------------------------------------*
*&
*&
*&---------------------------------------------------------------------*

REPORT zrep_lclclass.

CLASS zcl_static_instance_demo DEFINITION.
  PUBLIC SECTION.
    " Instance attribute and method
    DATA: gv_instance_value TYPE i.
    METHODS: increase_instance_value.

    " Static attribute and method
    CLASS-DATA: gv_static_value TYPE i.
    CLASS-METHODS: increase_static_value.
ENDCLASS.

CLASS zcl_static_instance_demo IMPLEMENTATION.

  METHOD increase_instance_value.
    gv_instance_value = gv_instance_value + 1.
    WRITE: / 'Instance Value:', gv_instance_value.
  ENDMETHOD.

  METHOD increase_static_value.
    gv_static_value = gv_static_value + 1.
    WRITE: / 'Static Value:', gv_static_value.
  ENDMETHOD.

ENDCLASS.

START-OF-SELECTION.

  WRITE: / '--- Static Method Calls (No object needed) ---'.
  zcl_static_instance_demo=>increase_static_value( ). " 1
  zcl_static_instance_demo=>increase_static_value( ). " 2

  SKIP.

  WRITE: / '--- Instance Method Calls (Using object) ---'.
  DATA(lo_obj1) = NEW zcl_static_instance_demo( ).
  lo_obj1->increase_instance_value( ). " 1
  lo_obj1->increase_instance_value( ). " 2

  SKIP.

  WRITE: / '--- Another Object with Separate Instance ---'.
  DATA(lo_obj2) = NEW zcl_static_instance_demo( ).
  lo_obj2->increase_instance_value( ). " 1 (separate from lo_obj1)

  SKIP.

  WRITE: / '--- Static Again (Still shared) ---'.
  zcl_static_instance_demo=>increase_static_value( ). " 3

Output :