ABAP Objects Design Patterns – Model View Controller (MVC) Part 3

First Demo Application – ALV

For our first Application view will be ALV output. To get the data for the ALV into the application, we will use the reference of the MODEL class created in the Controller. This way our model class is entrily separated by the view.

Code Snippet for View 1: ALV of MVC design

 
*&---------------------------------------------------------------------*
*& Purpose - ABAP Design Patterns - Model View Controller MVC - ALV demo
*& Author  - Naimesh Patel
*& URL     - http://zevolving.com/?p=52
*&---------------------------------------------------------------------*
*
REPORT  ztest_mvc_alv.
*
START-OF-SELECTION.
*---------
* Controller
*---------
  DATA: lo_control TYPE REF TO zcl_control.
*
* Iniiate controller
  CREATE OBJECT lo_control.
*
* Get the object from Control
  CALL METHOD lo_control->get_object
    EXPORTING
      if_name = 'ZCL_MODEL'.
*
*---------
* Model - Business Logic
*---------
* Date Range
  DATA: r_erdat  TYPE RANGE OF vbak-erdat,
        la_erdat LIKE LINE OF r_erdat.
*
  la_erdat-SIGN = 'I'.
  la_erdat-OPTION = 'BT'.
  la_erdat-LOW = sy-datum - 10.
  la_erdat-HIGH = sy-datum.
  APPEND la_erdat TO r_erdat.
*
* Get data method
  CALL METHOD lo_control->o_model->get_data
    EXPORTING
      ir_erdat = r_erdat.
*
*---------
* View - ALV output
*---------
  DATA: lo_alv TYPE REF TO cl_salv_table.
*
  DATA: lx_msg TYPE REF TO cx_salv_msg.
  TRY.
      cl_salv_table=>factory(
        IMPORTING
          r_salv_table = lo_alv
        CHANGING
          t_table      = lo_control->o_model->t_vbak ).
    CATCH cx_salv_msg INTO lx_msg.
  ENDTRY.
*
*
* Displaying the ALV
  lo_alv->display( ).
 

First Demo Application – SmartForms Output

Our Second application is fairly simple once we have implemented the first application as our core logic of getting the data is out of the report. In this application only part which differs is calling the Smartform.

Code Snippet for View 2: Smartforms of MVC design

 
*&---------------------------------------------------------------------*
*& Purpose - ABAP Design Patterns - Model View Controller MVC - 
*&           SmartForms Demo
*& Author  - Naimesh Patel
*& URL     - http://zevolving.com/?p=52
*&---------------------------------------------------------------------*
*
REPORT  ztest_mvc_view_2_ssf.
*
START-OF-SELECTION.
*---------
* Controller
*---------
  DATA: lo_control TYPE REF TO zcl_control.
*
* Iniiate controller
  CREATE OBJECT lo_control.
*
* Get the object from Control
  CALL METHOD lo_control->get_object
    EXPORTING
      if_name = 'ZCL_MODEL'.
*
*---------
* Model - Business Logic
*---------
* Date Range
  DATA: r_erdat  TYPE RANGE OF vbak-erdat,
        la_erdat LIKE LINE OF r_erdat.
*
  la_erdat-SIGN = 'I'.
  la_erdat-OPTION = 'BT'.
  la_erdat-LOW = sy-datum - 10.
  la_erdat-HIGH = sy-datum.
  APPEND la_erdat TO r_erdat.
*
* Get data method
  CALL METHOD lo_control->o_model->get_data
    EXPORTING
      ir_erdat = r_erdat.
*
*---------
* View - Smartform Output
*---------
* Smartform FM
  DATA: l_form TYPE tdsfname VALUE 'ZTEST_MVC_VIEW_2',
        l_fm   TYPE rs38l_fnam.
*
  CALL FUNCTION 'SSF_FUNCTION_MODULE_NAME'
    EXPORTING
      formname           = l_form
    IMPORTING
      fm_name            = l_fm
    EXCEPTIONS
      no_form            = 1
      no_function_module = 2
      OTHERS             = 3.
*
* calling Smartform FM
  DATA: ls_control  TYPE ssfctrlop.  " Controlling info
  DATA: ls_composer TYPE ssfcompop.  " Output info
*
  CALL FUNCTION l_fm
    EXPORTING
      control_parameters = ls_control
      output_options     = ls_composer
      user_settings      = ' '
      t_vbak             = lo_control->o_model->t_vbak
    EXCEPTIONS
      formatting_error   = 1
      internal_error     = 2
      send_error         = 3
      user_canceled      = 4
      OTHERS             = 5.
  IF sy-subrc <> 0.
    MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
            WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
  ENDIF.
 

Let’s say, in future we enhanced the business logic model class and now we want to implement for the business. In this case, we just have to change the object reference created in the Controller and we are good to go. Obviously, we have to take care of the newly created methods or methods which parameters are enhanced.