Behavior Extension - an example of developer extensibility

[SumitKundu]

Recently I got to apply one of the developer extensibility use cases, i.e., RAP behavior extension in a standard app. In this blog post I am sharing the example of such an ABAP extension implementation.

My use case was to do a validation and provide a warning message at reservation document item level when creating or editing an reservation document in 'Manage Manual Reservations' app (F4839).

The app Manage Manual Reservations uses a RAP BO interface I_ReservationDocument. So our target interface BO would be this which will be extended. Now if we examine the standard behavior definition as shown below, we get to know that it is 'extensible' and also which behavior definitions need to be extended. Please note that here we are looking at the interface behavior and not the behavior projection as developer extensibility allows only extensible interface views to be extended.

Standard Behavior definition

Steps:

1. Before creating the actual development objects, there are some pre-requisites. Since developer extensions are cloud-ready, it is a best practice to create them in a separate package if you are working on an on-premise systems. Please follow this blog post by vijay.sharma4 to set up the packages and software component in an on-premise SAP S/4HANA system.


2. I extended the standard behavior as below:
   

   extension using interface i_reservationdocumenttp
   
   implementation in class zbp_e_reservationdocumentheade unique;
   
   
   
   extend behavior for ReservationDocument
   
   {
   
     extend draft determine action Prepare {
   
       validation ReservationDocumentItem~validateStockItem;
   
     }
   
   }
   
   
   
   extend behavior for ReservationDocumentItem
   
   {
   
     validation validateStockItem on save { field Reservation; create; update; }
   
   }

   
   


3.  The behavior implementation class was implemented. This is no different than the usual behavior implementation.

*"* use this source file for the definition and implementation of

*"* local helper classes, interface definitions and type

*"* declarations

CLASS lhc_reservationdocumentheader DEFINITION INHERITING FROM cl_abap_behavior_handler.

  PUBLIC SECTION.



    CONSTANTS:

      validate_stock_item TYPE string VALUE 'VALIDATE_STOCK_ITEM',

      serial_num          TYPE  zser_num     VALUE  '001'.



  PRIVATE SECTION.

    METHODS validatestockitem FOR VALIDATE ON SAVE

      IMPORTING keys FOR reservationdocumentitem~validatestockitem.



ENDCLASS.



CLASS lhc_reservationdocumentheader IMPLEMENTATION.



  METHOD validatestockitem.



*Get the reservation document items

    READ ENTITIES OF i_reservationdocumenttp IN LOCAL MODE

      ENTITY reservationdocumentitem

       FIELDS ( product plant storagelocation )

      WITH CORRESPONDING #( keys )

      RESULT DATA(lt_items).



    LOOP AT lt_items ASSIGNING FIELD-SYMBOL(<ls_res_item>)

      WHERE reservationitmismarkedfordeltn EQ abap_false

        AND reservationitemisfinallyissued EQ abap_false

        AND product IS NOT INITIAL

        AND plant IS NOT INITIAL.  "#EC CI_STDSEQ

*If stock is zero for the material and plant combination,

*issue a warning message

      SELECT SUM( labst ) FROM nsdm_e_mard

        INTO @DATA(quantity_in_stock)

          WHERE matnr EQ  @<ls_res_item>-product

            AND werks EQ @<ls_res_item>-plant.

      IF sy-subrc EQ 0.

        IF quantity_in_stock EQ 0.

          APPEND VALUE #( %tky = <ls_res_item>-%tky

                %state_area = validate_stock_item

                %path-reservationdocument-%is_draft = <ls_res_item>-%is_draft

                %path-reservationdocument-reservation = <ls_res_item>-reservation

               )

      TO reported-reservationdocumentitem.

          APPEND VALUE #( %tky        = <ls_res_item>-%tky

                              %state_area = validate_stock_item

                              %msg        = NEW zcm_reservation_message(

                                                  textid   = zcm_reservation_message=>stock_unavailable

                                                  severity = if_abap_behv_message=>severity-warning

                                                  product = <ls_res_item>-product

                                                  plant = <ls_res_item>-plant

                                                   )

                              %element-resvnitmrequiredqtyinentryunit = if_abap_behv=>mk-on

                              %path-reservationdocument-%is_draft   = <ls_res_item>-%is_draft

                              %path-reservationdocument-reservation = <ls_res_item>-reservation

                            )

              TO reported-reservationdocumentitem.

        ENDIF.

      ENDIF.



    ENDLOOP.



  ENDMETHOD.





ENDCLASS.

Test:

Now when I try to create or update the reservation document item, the error message is thrown as expected.

Warning message from RAP BO validation

Reference:

https://blogs.sap.com/2019/07/25/sap-s4hana-extensibility-a-learning-journey/

https://blogs.sap.com/2022/10/25/new-extenisbility-guide-for-s-4hana-is-available/

SAP Official Documentation on Developer Extensibility on ABAP Platform