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:

singleton class – SAP EWM Help

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

Key Characteristics of Singleton Pattern: