Multiple Inheritance Using Interfaces in ABAP

 

• In ABAP Object Oriented Programming, we cannot achieve Multiple inheritance using Normal Class or Abstract Class because we can only pass one class as a super Class.

  • We can see this in SE24 ( Class Builder ).
  
  
  

  
  

  • As we can see, we can only pass one parameter at a time.

  • However, we can pass multiple interfaces in a class.

    
    
    

    
    

  • and by using this mechanism we can achieve Multiple inheritance using Interfaces in ABAP.

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let’s take a requirement and implement it practically.

Requirement :-

• We have to create two radio buttons and one Select option Input for Sales Document Number on the Selection Screen.
• The Customer wants that we should use two interfaces and implement it inside one class.
• IF Sales radio button is selected then It should be displaying VBAK details.
• Else If Billing Radio button is selected then it should be displaying VBRK details.

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Solution :-

• Step 1 :- Go to transaction code SE38 ( ABAP Editor ) and create a executable program.

  
  
  

  
  

• Step 2 :- Create internal table for VBAK and VBRK table.

  
  
  

  
  

• Step 3 :- Define two radio buttons and one select option for user input.

  
  
  

  
  

• Step 4 :- Create Sales interface and Billing Interface with one method.

  
  
  

  
  

• Step 5 :- Create a class and implement these above methods.

  
  
  

  
  

• Step 6 :- In start of selection create object for the class.

  
  
  

  
  

• Step 7 :- Call the method according to the radio button and use factory method of CL_SALV_TABLE class to display in form of ALV.

  
  
  

  
  

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Code :-

*&---------------------------------------------------------------------*
*& Report ZAR_MULTIPLE_INHERITANCE
*&---------------------------------------------------------------------*
*&
*&---------------------------------------------------------------------*
REPORT ZAR_MULTIPLE_INHERITANCE.

DATA : lt_vbak type table of vbak,
       lt_vbrk type table of vbrk.

DATA : lv_vbeln type vbeln_va.
SELECT-OPTIONS : s_vbeln for lv_Vbeln.
PARAMETERS : p_rad1 type c RADIOBUTTON GROUP r1,
             p_rad2 type c RADIOBUTTON GROUP r1.

INTERFACE Sales.
  METHODS DISPLAY_SALES_ORDER.

ENDINTERFACE.

INTERFACE Billing.
  METHODS DISPLAY_BILLING.

ENDINTERFACE.

CLASS ORDER DEFINITION.
  PUBLIC SECTION.
  INTERFACES : Sales,
             Billing.

ENDCLASS.
CLASS ORDER IMPLEMENTATION.
  METHOD SALES~display_sales_order.
    select * from vbak
      into table lt_vbak
      where vbeln in s_vbeln.
  ENDMETHOD.

  METHOD BILLING~display_billing.
    select * from vbrk
      into table lt_vbrk
      where vbeln in s_vbeln.
  endmethod.
ENDCLASS.

START-OF-SELECTION.
DATA(lo_object) = new ORDER( ).

if p_rad1 = 'X'.
  lo_object->Sales~display_sales_order( ).

  TRY.
  CALL METHOD cl_salv_table=>factory
    EXPORTING
      list_display   = IF_SALV_C_BOOL_SAP=>FALSE
    IMPORTING
      r_salv_table   = data(lo_disp1)
    CHANGING
      t_table        = lt_vbak
      .
    CATCH cx_salv_msg.
  ENDTRY.
  lo_disp1->display( ).

elseif p_rad2 = 'X'.

  lo_object->Billing~display_billing( ).

  TRY.
  CALL METHOD cl_salv_table=>factory
    EXPORTING
      list_display   = IF_SALV_C_BOOL_SAP=>FALSE
    IMPORTING
      r_salv_table   = data(lo_disp2)
    CHANGING
      t_table        = lt_vbrk
      .
    CATCH cx_salv_msg.
  ENDTRY.
  lo_disp2->display( ).

endif.

*&---------------------------------------------------------------
*&End of Program
*&------------------------------------------------------------------

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Execute the code:-

1. Select Sales Order Display radio button

• Press F8.

  
  
  

  
  

• Now go back.

2. Select Billing Display Radio button.

• Press F8.