Preface – This post is part of the ABAP Programs series.

Type Casting in ABAP Class

Note: If you are searching for basic type casting/conversion of ABAP variable in Reports/Program, click here.

Prerequisite:

1. You must have a basic Idea of local class and instance/reference of class.

2. Inheritance and Polymorphism concept

Note: Parent Class is also called base class and Child class is also called Sub class.

What is Static and Dynamic Type?

Before we talk about type casting, we need to know what are static Type and Dynamic type. Each reference variable has a dynamic type and a static type.

Suppose we have a class C1 and its child class C2.

So, in our program we will write following code to make reference and create object.

DATA: obj1 TYPE REF TO C1.

Here obj1 is our reference variable and C1 is the Static Type.

Thus anything that comes after TYPE REF TO is a static type because the object obj1 is pointing to fixed or static type [here class C1].

Now, in our code, we proceed as below:

CREATE OBJECT obj1.

In this line we actually point to the class C1 using our object obj1. This pointing is called Dynamic Type and it is pointing to C1 same as the static type above.

We can also write following code:

CREATE OBJETC obj1 TYPE C2.

In this line we are pointing to child class C2 of C1. This pointing is defined at runtime and called as Dynamic Type, and this time it is not same as the static type.

Thus we conclude that Dynamic type is defined at runtime of the program while static type is declared with the declaration of reference variable. Static type can be same as Dynamic type or less specific than it [it means, it can just point to the parents and not all the child unlike the dynamic type which can].

What is a Type casting?

Type Casting in ABAP is just like casting in other computer languages. It is one way of inheriting the properties from either base/parent class or sub/child class into one another. It is used to cast one data type, class or Interface into another data type, class or interface.

For data type casting, refer here.

Definition:

Type casting is a process of converting reference of class or interface to another, given both the class are from same hierarchy i.e. either one of them must be a parent class and the other a child class.

Syntax:

Destination_Ref = | ?= Source_Ref.

Some questions for you:

Why do we need Type casting?

How to achieve a type casting?

Example of Type casting

What are types of Type Casting?

Some Basic rules of type casting.

Preface – This post is part of the ABAP Programs series.

To delete duplicates in ABAP either from a string or an internal table, we need to use ABAP statement “DELETE ADJACENT DUPLICATES FROM”. In this article, we have taken an example, which implements deletion of duplicate data when two strings are merged. This process also involves internal table.

Introduction

DELETE ADJACENT DUPLICATES FROM <Internal Table> COMPARING <field name>.

Using the ABAP statement mentioned above, we can compare values of a column of any table/ internal table and delete the duplicates. Once the duplicates are deleted, we get unique values from a string/ internal table.

SPLIT <variable> AT ‘,’ INTO TABLE <internal table>.

Using the ABAP statement mentioned above, we can divide a string in to a form of internal table where each data is separated by comma ‘,’.

ABAP Program to Delete duplicates

DATA : lv_string       TYPE string,
       lv_string2      TYPE string,
       lv_string_final TYPE string.
TYPES: BEGIN OF ty_data,
         auth TYPE c,
       END OF ty_data.
DATA: ls_user  TYPE ty_data,
      ls_user2 TYPE ty_data,
      lt_user2 TYPE TABLE OF ty_data,
      lt_user  TYPE TABLE OF ty_data.
lv_string = 'a,b,c,a'.
lv_string2 = 'd,b,c,a'.
SPLIT lv_string AT ',' INTO TABLE lt_user.
SPLIT lv_string2 AT ',' INTO TABLE lt_user2.
LOOP AT lt_user2 ASSIGNING FIELD-SYMBOL(<fs_field>).
  INSERT  <fs_field> INTO TABLE lt_user.
ENDLOOP.
  SORT lt_user BY auth.
  DELETE ADJACENT DUPLICATES FROM lt_user COMPARING auth.
  IF sy-subrc = 0.
    LOOP AT lt_user ASSIGNING FIELD-SYMBOL(<fs_user_table>).
        IF lv_string_final IS INITIAL.
          lv_string_final = <fs_user_table>-auth.
        ELSE.
          CONCATENATE  lv_string_final <fs_user_table>-auth INTO lv_string_final SEPARATED BY ','.
        ENDIF.
    ENDLOOP.
  ENDIF.
WRITE lv_string_final.​

Explanation

Here, we have written program which tIn the above program, following steps have been implemented:

1. Initially, we have defined variables: lv_string, lv_string2 and lv_string_final of type string. These variables will be used to feed two input strings and save the merged the string.
2. Now, we have defined a structure with one field. We have created this so that we can use this field to perform duplicate deletion.
3. Again, we have defined variables: ls_user, ls_user2, lt_user2 and lt_user. These are the work areas (ls) and internal tables (lt). These will be used to store data line by line from the strings defined in step 01 above.
4. Now, we will feed some default data in form of strings i.e. lv_string = ‘a,b,c,a’ and lv_string2 = ‘d,b,c,a’. These variables do contain duplicate data.
5. Here, we converted the strings into internal table.
6. Then, we deleted duplicates from the internal table created above.
7. Then, we have again concatenated the new internal table data i.e. unique data into a string divided by comma ‘,’.
8. In the end, we have printed the string as output.

Preface – This post is part of the ABAP Programs series.

TYPE-POOLS truxs.
PARAMETERS p_file TYPE rlgrap-filename.
TYPES : BEGIN OF t_tab,
          workstream TYPE char50,
          task       TYPE zci_task,
          task_type  TYPE char50,
        END OF t_tab.
DATA : t_upload1  TYPE STANDARD TABLE OF ZDEMO_TEST2,
       wa_upload1 TYPE ZDEMO_TEST2.

AT SELECTION-SCREEN ON VALUE-REQUEST FOR p_file.
  CALL FUNCTION 'F4_FILENAME'
    EXPORTING
      field_name = 'P_FILE'
    IMPORTING
      file_name  = p_file.

START-OF-SELECTION.
  CALL FUNCTION 'TEXT_CONVERT_XLS_TO_SAP'
    EXPORTING
      i_tab_raw_data       = it_type
      i_filename           = p_file
    TABLES
      i_tab_converted_data = t_upload[]
    EXCEPTIONS
      conversion_failed    = 1
      OTHERS               = 2.
  IF sy-subrc <> 0.
    MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
            WITH sy-msgv1 sy-msgv2 .
  ENDIF.

CALL FUNCTION 'UPLOAD_XLS_FILE_2_ITAB'
  EXPORTING
    i_filename       = p_file
  tables
    e_itab           = t_upload1
 EXCEPTIONS
   FILE_ERROR       = 1
   OTHERS           = 2
          .
IF sy-subrc <> 0.
 Implement suitable error handling here
ENDIF.


END-OF-SELECTION.
  DATA : ls_cc_impl TYPE ZDEMO_TEST2,
         lt_cc_impl TYPE STANDARD TABLE OF  ZDEMO_TEST2.
  LOOP AT t_upload1 INTO wa_upload1.
    ls_cc_impl-mandt = sy-mandt.
    ls_cc_impl-INCIDENT                  = wa_upload1-INCIDENT.
    APPEND ls_cc_impl TO lt_cc_impl.
  ENDLOOP.
  MODIFY ZDEMO_TEST2 FROM TABLE lt_cc_impl.

CLASS cl_grand DEFINITION.
  PUBLIC SECTION.
    CLASS-DATA v_test TYPE char40.
    CLASS-METHODS class_constructor.
    METHODS constructor.
    DATA a type i.
    CLASS-DATA b TYPE i.
ENDCLASS.                    "cl_grand DEFINITION

*----------------------------------------------------------------------*
*       CLASS cl_grand IMPLEMENTATION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS cl_grand IMPLEMENTATION.
  METHOD class_constructor.
    v_test = 'Static Constructor - Grand Parent'.
    b = 30.
    WRITE: /3 v_test.
  ENDMETHOD.                    "class_constructor
  METHOD constructor.
    a = 30.
    v_test = 'Instance Constructor - Grand Parent'.
    WRITE: /3 v_test.
  ENDMETHOD.
ENDCLASS.                    "cl_grand IMPLEMENTATION

*----------------------------------------------------------------------*
*       CLASS cl_parent DEFINITION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS cl_parent DEFINITION INHERITING FROM cl_grand.
  PUBLIC SECTION.
    CLASS-METHODS class_constructor.
    METHODS constructor.

ENDCLASS.                    "cl_parent DEFINITION

*----------------------------------------------------------------------*
*       CLASS cl_parent IMPLEMENTATION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS cl_parent IMPLEMENTATION.
  METHOD class_constructor.
    v_test = 'Static Constructor - Parent'.
    b = 20.
    WRITE: /3 v_test.
  ENDMETHOD.                    "class_constructor
  METHOD constructor .
*    data a type i.

    super->constructor( ).
    a = 20.
    v_test = 'Instance Constructor -Parent'.
    WRITE: /3 v_test.
  ENDMETHOD.
ENDCLASS.                    "cl_parent IMPLEMENTATION

*----------------------------------------------------------------------*
*       CLASS cl_child DEFINITION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS cl_child DEFINITION INHERITING FROM cl_parent.
  PUBLIC SECTION.
    CLASS-METHODS class_constructor.
    METHODS constructor.
*    DATA a.
ENDCLASS.                    "cl_child DEFINITION

*----------------------------------------------------------------------*
*       CLASS cl_child IMPLEMENTATION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS cl_child IMPLEMENTATION.
  METHOD class_constructor.
    v_test = 'Static Constructor - Child'.
    WRITE: /3 v_test.
    b = 10.
  ENDMETHOD.                    "class_constructor
  METHOD constructor.
    data a type i.
a = 10.
    super->constructor( ).

    v_test = 'Instance Constructor - Child'.
    WRITE: /3 v_test.
  ENDMETHOD.
ENDCLASS.                    "cl_child IMPLEMENTATION
START-OF-SELECTION.
DATA obj_child TYPE REF TO cl_child.
CREATE OBJECT obj_child.
data: a type i,
      b type i.
a = obj_child->a.
write a.

write sy-uname.
delete from ztms_score .
delete from ztms_ans .
TYPES: BEGIN OF TY_DATA, "user defined type
       ID TYPE N ,
       NAME TYPE CHAR20,
       SALARY TYPE I,
      END OF TY_DATA.
DATA : ITAB TYPE TABLE OF TY_DATA. "internal table
DATA : WA TYPE TY_DATA. "work area

WA-ID = 1.
WA-NAME = 'Sapnuts'.
WA-SALARY = 5000.
COLLECT WA INTO ITAB. "collect
CLEAR WA.

WA-ID = 2.
WA-NAME = 'SAPabap'.
WA-SALARY = 50000.
COLLECT WA INTO ITAB. "collect
CLEAR WA.

WA-ID = 1.
WA-NAME = 'Sapnuts'.
WA-SALARY = 15000.
COLLECT WA INTO ITAB. "collect
CLEAR WA.

LOOP AT ITAB INTO WA.
  WRITE:/ WA-ID, WA-NAME, WA-SALARY. "loop and display data
ENDLOOP.
**delete from ztms_score .
**delete from ztms_ans .
delete from ztms_user .
delete from ztms_set .
delete from ztms_ques .

Preface – This post is part of the ABAP Programs series.

CLASS a1 DEFINITION.
PUBLIC SECTION.
DATA: num1 TYPE i VALUE 100.
METHODS:m1.
ENDCLASS.

CLASS a1 IMPLEMENTATION.
METHOD m1.
WRITE: 'a1:',num1.
ENDMETHOD.
ENDCLASS.

CLASS b1 DEFINITION INHERITING FROM a1.
PUBLIC SECTION.
METHODS:m2, m1 REDEFINITION.
ENDCLASS.

CLASS b1 IMPLEMENTATION.
METHOD m1.
num1 = num1 .
WRITE: 'b1:',num1.
ENDMETHOD.

METHOD m2.
WRITE: 'M2 in class b1'.
ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.

DATA: a TYPE REF TO a1.
DATA: b TYPE REF TO b1.
*data: c type REF TO c1.


****************************************************************
CREATE OBJECT b.
a = b. "upcasting
CALL METHOD a->m1( ).
*call METHOD a->m2( ). " we can't access the own sub class methods using super class ref.
NEW-LINE.

b ?= a. " down casting
CALL METHOD b->m1( ).
NEW-LINE.
CALL METHOD b->m2( ).

*****************************************************************
" error null ref
create OBJECT a.
b ?= a. "down casting still its giving dump
call METHOD b->m1( ).

*****************************************************************

CREATE OBJECT a.
TRY.
 b ?= a. "u r attempted to use a 'NULL' object reference dump
CATCH cx_sy_move_cast_error.
 CALL METHOD b->m1( ).
ENDTRY.

*****************************************************************

CREATE OBJECT a.
CREATE OBJECT b.
TRY.
 b ?= a.
CATCH cx_sy_move_cast_error.
 CALL METHOD b->m1( ).
 call METHOD b->m2( ).
ENDTRY.




CLASS lcl_shape DEFINITION.
  PUBLIC SECTION.
    METHODS draw.
ENDCLASS.

CLASS lcl_circle DEFINITION INHERITING FROM lcl_shape.
  PUBLIC SECTION.
    METHODS: draw REDEFINITION,
      calc_area.
ENDCLASS.

CLASS lcl_shape IMPLEMENTATION.
  METHOD draw.
    WRITE :/ 'Drawing any Shape'.
  ENDMETHOD.
ENDCLASS.

CLASS lcl_circle IMPLEMENTATION.
  METHOD draw.
    WRITE :/ 'Drawing specific shape: Circle'.
  ENDMETHOD.

  METHOD calc_area.
    WRITE :/ 'Area Of Crcle = 2iiR'.
  ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.
  DATA : o_cir TYPE REF TO lcl_circle.
  CREATE OBJECT o_cir.
  CALL METHOD o_cir->draw( ). " calls subclass Draw() method
  CALL METHOD o_cir->calc_area( ).
  ULINE.
  "--------- Narrow cast(Upcast)---------------"
  DATA : o_shp TYPE REF TO lcl_shape.
  o_shp = o_cir. "  Narrow cast(Upcast)
  CALL METHOD o_shp->draw( ). " calls sub class Draw() method
  "call METHOD o_shp->calc_area( ) . " compilation error
  ULINE.

  "---------- Widening Cast(Downcast) -----------"

  DATA : o_cir1 TYPE REF TO lcl_circle.

  " o_cir1 = o_shp. "  complilation error
  o_cir1 ?= o_shp.  " Widening Cast(Downcast)
  CALL METHOD o_cir1->draw( ). " calls subclass Draw() method
  CALL METHOD o_cir1->calc_area( ).

CLASS a1 DEFINITION.
PUBLIC SECTION.
DATA: num1 TYPE i VALUE 100.
METHODS:m1.
ENDCLASS.

CLASS a1 IMPLEMENTATION.
METHOD m1.
WRITE: 'a1:',num1.
ENDMETHOD.
ENDCLASS.

CLASS b1 DEFINITION INHERITING FROM a1.
PUBLIC SECTION.
METHODS:m2, m1 REDEFINITION.
ENDCLASS.

CLASS b1 IMPLEMENTATION.
METHOD m1.
num1 = num1 .
WRITE: 'b1:',num1.
ENDMETHOD.

METHOD m2.
WRITE: 'M2 in class b1'.
ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.

DATA: parent TYPE REF TO a1.
DATA: child TYPE REF TO b1.
*data: c type REF TO c1.


****************************************************************
CREATE OBJECT child.
parent = child. "upcasting
CALL METHOD parent->m1( ).
CALL METHOD child->m1( ).
CALL METHOD child->m2( ).
*call METHOD a->m2( ). " we can't access the own sub class methods using super class ref.
NEW-LINE.

child ?= parent. " down casting
CALL METHOD child->m1( ).
NEW-LINE.
CALL METHOD child->m2( ).

******************************************************************
*" error null ref
*create OBJECT a.
*b ?= a. "down casting still its giving dump
*call METHOD b->m1( ).

******************************************************************
*
CREATE OBJECT a.
TRY.
 b ?= a. "u r attempted to use a 'NULL' object reference dump
CATCH cx_sy_move_cast_error.
 CALL METHOD b->m1( ).
ENDTRY.

******************************************************************
*
CREATE OBJECT a.
CREATE OBJECT b.
TRY.
 b ?= a.
CATCH cx_sy_move_cast_error.
 CALL METHOD b->m1( ).
 call METHOD b->m2( ).
ENDTRY.

******** Unique Values******************
 
DATA : lv_string       TYPE string,
       lv_string2      TYPE string,
       lv_string_final TYPE string.
TYPES: BEGIN OF ty_data,
         auth TYPE c,
       END OF ty_data.
DATA: ls_user  TYPE ty_data,
      ls_user2 TYPE ty_data,
      lt_user2 TYPE TABLE OF ty_data,
      lt_user  TYPE TABLE OF ty_data.
lv_string = 'a,b,c,a'.
lv_string2 = 'd,b,c,a'.
SPLIT lv_string AT ',' INTO TABLE lt_user.
SPLIT lv_string2 AT ',' INTO TABLE lt_user2.
LOOP AT lt_user2 ASSIGNING FIELD-SYMBOL(<fs_field>).
  INSERT  <fs_field> INTO TABLE lt_user.
ENDLOOP.
  SORT lt_user BY auth.
  DELETE ADJACENT DUPLICATES FROM lt_user COMPARING auth.
  IF sy-subrc = 0.
    LOOP AT lt_user ASSIGNING FIELD-SYMBOL(<fs_user_table>).
        IF lv_string_final IS INITIAL.
          lv_string_final = <fs_user_table>-auth.
        ELSE.
          CONCATENATE  lv_string_final <fs_user_table>-auth INTO lv_string_final SEPARATED BY ','.
        ENDIF.
    ENDLOOP.
  ENDIF.
WRITE lv_string_final.

Preface – This post is part of the ABAP Programs series.

Introduction

ALV in ABAP enables users to view data in a tabular format. We can even make it editable. In this article, we will explore the same.

Editable ALV Program in ABAP

************************************************************************
*   INTERNAL TABLES
************************************************************************

DATA: lt_mapping  TYPE STANDARD TABLE OF zBarry_emp,
      lt_fieldcat TYPE lvc_t_fcat.

************************************************************************
*   WORK AREAS
************************************************************************
DATA: ls_fieldcat TYPE lvc_s_fcat,
      ls_mapping  TYPE zBarry_emp,
      lw_layout   TYPE lvc_s_layo.

************************************************************************
*   REFERENCE OBJECT
************************************************************************
DATA:  r_container TYPE REF TO cl_gui_custom_container,
       r_grid      TYPE REF TO cl_gui_alv_grid.


************************************************************************
*   Field symbol
************************************************************************

FIELD-SYMBOLS: <ls_fieldcat>   TYPE lvc_s_fcat.

************************************************************************
*   START-OF-SELECTION.
************************************************************************
START-OF-SELECTION.
  SELECT *
    FROM zBarry_emp
    INTO TABLE lt_mapping
    UP TO 20 ROWS.

* Call screen 200
  CALL SCREEN 200.

MODULE status_0200 OUTPUT.
  SET PF-STATUS 'PF-STATUS'.
  SET TITLEBAR 'TITLE'.

  CREATE OBJECT r_container
    EXPORTING
      container_name = 'CUSTOM_1'.

  CREATE OBJECT r_grid
    EXPORTING
      i_parent = r_container.


* create Field Catalog
  ls_fieldcat-fieldname = 'EMP_FNAME'.
  ls_fieldcat-tabname   = 'zBarry_emp'.
  ls_fieldcat-seltext   = 'Employee Name'.
  ls_fieldcat-edit      = 'X'.
  APPEND ls_fieldcat TO lt_fieldcat.
  CLEAR ls_fieldcat.

  ls_fieldcat-fieldname = 'EMP_LNAME'.
  ls_fieldcat-tabname   = 'zBarry_emp'.
  ls_fieldcat-seltext   = 'Employee Last Name'.
  ls_fieldcat-edit      = 'X'.
*ls_fieldcat-hotspot   = 'X'.
  APPEND ls_fieldcat TO lt_fieldcat.
  CLEAR ls_fieldcat.

  CALL METHOD r_grid->set_table_for_first_display
    EXPORTING
*     I_BUFFER_ACTIVE               =
*     I_BYPASSING_BUFFER            =
*     I_CONSISTENCY_CHECK           =
      i_structure_name              = 'zBarry_emp'
*     IS_VARIANT                    =
      i_save                        = 'A'
      i_default                     = abap_true
      is_layout                     = lw_layout
*     IS_PRINT                      =
*     IT_SPECIAL_GROUPS             =
*     IT_TOOLBAR_EXCLUDING          =
*     IT_HYPERLINK                  =
*     IT_ALV_GRAPHICS               =
*     IT_EXCEPT_QINFO               =
*     IR_SALV_ADAPTER               =
    CHANGING
      it_outtab                     = lt_mapping
      it_fieldcatalog               = lt_fieldcat
*     IT_SORT                       =
*     IT_FILTER                     =
    EXCEPTIONS
      invalid_parameter_combination = 1
      program_error                 = 2
      too_many_lines                = 3
      OTHERS                        = 4.
  IF sy-subrc <> 0.
* Implement suitable error handling here
  ENDIF.




ENDMODULE.

*&---------------------------------------------------------------------*
*&      Module  USER_COMMAND_0200  INPUT
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
MODULE user_command_0200 INPUT.

  CASE sy-ucomm.
    WHEN 'BACK' OR 'EXIT' OR 'CANCEL'.
      LEAVE PROGRAM.
      LEAVE TO SCREEN 0.
    WHEN 'SAVE'.
      DATA: lt_t_row TYPE lvc_t_row,
            ls_t_row LIKE LINE OF lt_t_row
            .
      FIELD-SYMBOLS: <fs_changed_data> LIKE LINE OF lt_mapping.
      CALL METHOD r_grid->check_changed_data.
      CALL METHOD r_grid->get_selected_rows
        IMPORTING
          et_index_rows = lt_t_row.   " Indexes of Selected Rows

      LOOP AT lt_t_row INTO ls_t_row.

        READ TABLE lt_mapping ASSIGNING <fs_changed_data> INDEX ls_t_row-index.
        IF sy-subrc = 0.
          MODIFY zBarry_emp FROM  <fs_changed_data>.
        ENDIF.
      ENDLOOP.
  ENDCASE.
ENDMODULE.

Preface – This post is part of the ABAP Programs series.

In ABAP, you might have learned to create global classes using SE24, Transaction code. But some time, there is a requirement to create a local class and its method call altogether in a report. In this article, we will learn how to implement Local Classes in ABAP.

Introduction

Local Classes in ABAP are just like classes of Programming language C/C++. We define following while doing Local classes implementation in ABAP:

• Class: We define a class with different section: Public, Private and Protected
• Method: We define Importing, Exporting and Exception parameters for a Method
• Create Object: This we create for our Global classes too, used to create an object for a Class in our regular ABAP programs
• CALL METHOD: To call the methods of class, using the object created above.

ABAP Program

Program Requirement: Get basic and salary details of an employee from two different classes. Take Employee ID as input.

CLASS class_test DEFINITION DEFERRED.
PARAMETERS: p_empid TYPE char8.
DATA: wa_emp  TYPE zBarry_emp,
      wa_emp2 TYPE zBarry_sal.
DATA: obj TYPE REF TO class_test.

INTERFACE interface.
  METHODS: method2
    IMPORTING imp2 TYPE char8
    EXPORTING exp2 TYPE zBarry_sal.
ENDINTERFACE.

CLASS class_test DEFINITION.
  PUBLIC SECTION.
    EVENTS: event1.
    INTERFACES: interface.
    METHODS: method1
      IMPORTING imp TYPE char8
      EXPORTING exp TYPE zBarry_emp.
    METHODS: eventhandler FOR EVENT event1 OF class_test.

ENDCLASS.

CREATE OBJECT obj.

SET HANDLER obj->eventhandler FOR obj.
CALL METHOD obj->method1
  EXPORTING
    imp = p_empid
  IMPORTING
    exp = wa_emp.

CALL METHOD obj->interface~method2
  EXPORTING
    imp2 = p_empid
  IMPORTING
    exp2 = wa_emp2.

WRITE:/ wa_emp.
write:/ wa_emp2-empid, wa_emp2-tid,wa_emp2-mon.
*&---------------------------------------------------------------------*
*&       Class (Implementation)  class_test
*&---------------------------------------------------------------------*
*        Text
*----------------------------------------------------------------------*
CLASS class_test IMPLEMENTATION.
  METHOD method1.
    SELECT * FROM zBarry_emp INTO exp WHERE empid = imp.
    ENDSELECT.
    IF sy-subrc NE 0.
      RAISE EVENT event1 .
    ENDIF.
  ENDMETHOD.

  METHOD interface~method2.
    SELECT * FROM zBarry_sal INTO exp2 WHERE empid = imp2.
    ENDSELECT.
  ENDMETHOD.

  METHOD eventhandler.
    WRITE:/ 'wrong empid'.
  ENDMETHOD.
ENDCLASS.               "class_test

Code Explanation

In the above code, we have done following implementation, step by step:

1. Initially, we have defined Parameters to take Employee ID as input, variables to define work area to store data of Employee basic details and Salary details and object obj 
2. Implementation of  one local class and an interface.
3. Exporting Employee ID and getting relevant data from these classes/interface.
4. Printing above result using Write statement.

Preface – This post is part of the ABAP Programs series.

Lock Objects in SAP ABAP are global reusable component which generates function modules i.e. ENQUEUE_E_TABLE and DEQUEUE_E_TABLE that are used to set and release locks on data record. This Enqueue and Dequeue method is used to lock and unlock any object in SAP ABAP. In this article, we will learn these methods with the help of a program. Before starting this, you must read the basic concepts of Lock Objects in SAP ABAP.

Introduction

It is very important to lock an object that is under development. By object we mean everything i.e. Tables, Views, Reports, Methods, Function Modules, and all. ABAP too provides these features by default for their standard interfaces. But what if you need to create one for your own table. Then you need to use the given two Function Modules:

1. ENQUEUE_E_TABLE:  To Add Lock
2. DEQUEUE_E_TABLE: To Remove Lock

ABAP Program to perform Enqueue and Dequeue Operations

DATA: varkey LIKE rstable-varkey.
varkey = sy-mandt.
CALL FUNCTION 'ENQUEUE_E_TABLE' "Add Lock
  EXPORTING
*   MODE_RSTABLE   = 'E'
    tabname        = 'ZBarry_TEST'
    varkey         = varkey
*   X_TABNAME      = ' '
*   X_VARKEY       = ' '
*   _SCOPE         = '2'
*   _WAIT          = ' '
*   _COLLECT       = ' '
  EXCEPTIONS
    foreign_lock   = 1
    system_failure = 2
    OTHERS         = 3.
CASE sy-subrc.
  WHEN 1.
    MESSAGE i184(bctrain) WITH 'Foreign lock'.
  WHEN 2.
    MESSAGE i184(bctrain) WITH 'system failure'.
  WHEN 0.
    MESSAGE i184(bctrain) WITH 'success'.
  WHEN OTHERS.
    MESSAGE i184(bctrain) WITH 'others'.
ENDCASE.
CALL FUNCTION 'DEQUEUE_E_TABLE' "Remove Lock
  EXPORTING
*   MODE_RSTABLE       = 'E'
    tabname = 'ZBarry_TEST'
    varkey  = varkey
*   X_TABNAME          = ' '
*   X_VARKEY           = ' '
*   _SCOPE  = '3'
*   _SYNCHRON          = ' '
*   _COLLECT           = ' '
  .

IF sy-subrc <> 0.
* Implement suitable error handling here
ENDIF.

Code Explanation

The above program is self explanatory, still we will explain key points below:

• Initially, we have defined  a variable varkey which will give the client information. It tells, ABAP, for which client, you want to block/unblock the table. It is taken automatically using sy-mandt.
• Then we have called Function ‘ENQUEUE_E_TABLE’, it returns either either success, failure or Foreign lock exception.
• Later, when we are done with our changes regarding our table, we need to unlock the same. For that we call Function ‘DEQUEUE_E_TABLE’.