[ABAP] How do I define and use classes and objects in ABAP?

calendar Jul 24, 2023 · 2 min read · ABAP  ·
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In ABAP, classes can be defined using the keyword "CLASS" followed by the class name. Objects of these classes can be created using the "CREATE OBJECT" statement. Here's a step-by-step guide on defining and using classes and objects in ABAP:

  1. Define a class:

    • Go to the ABAP Development Tools (ADT) perspective in SAP NetWeaver or SAP GUI.
    • Create a new ABAP Class using the "New ABAP Class" option.
    • Provide a name for the class and define its visibility (private, protected, or public).
    • Define the attributes (data members) and methods (member functions) of the class.

  2. Define methods:

    • In the class editor, switch to the "Methods" tab.
    • Define the methods by providing a name, visibility, and return type.
    • Implement the method logic within the method body.

  3. Define attributes:

    • In the class editor, switch to the "Attributes" tab.
    • Define the attributes by providing a name, data type, and visibility.

  4. Save and activate the class.

  5. Create an object:

    • In your ABAP program/report, declare a variable of the class type.
    • Use the "CREATE OBJECT" statement to create an instance of the class and assign it to the variable.

  6. Use the object:

    • Access the attributes and methods of the object using the "->" operator.
    • Call the methods using the object reference and appropriate parameters.

Here's an example to illustrate the above steps:

 1CLASS lcl_my_class DEFINITION.
 2  PUBLIC SECTION.
 3    METHODS:
 4      constructor,
 5      display_msg IMPORTING iv_msg TYPE string,
 6      get_msg RETURNING VALUE(rv_msg) TYPE string.
 7  PRIVATE SECTION.
 8    DATA:
 9      mv_msg TYPE string.
10ENDCLASS.
11
12CLASS lcl_my_class IMPLEMENTATION.
13  METHOD constructor.
14    mv_msg = ''.
15  ENDMETHOD.
16
17  METHOD display_msg.
18    WRITE iv_msg.
19    mv_msg = iv_msg.
20  ENDMETHOD.
21
22  METHOD get_msg.
23    rv_msg = mv_msg.
24  ENDMETHOD.
25ENDCLASS.
26
27DATA: lo_my_object TYPE REF TO lcl_my_class.
28
29CREATE OBJECT lo_my_object.
30
31lo_my_object->display_msg( 'Hello World!' ).
32
33DATA(lv_msg) = lo_my_object->get_msg( ).
34WRITE lv_msg.

In the above example, a class named "lcl_my_class" is defined with a constructor, "display_msg" method, and "get_msg" method. An object "lo_my_object" is created using the "CREATE OBJECT" statement. The "display_msg" method is called to display a message, and then the "get_msg" method is called to retrieve the stored message and display it.