OO ABAP Object references

*&---------------------------------------------------------------------*
*& Report  YSAP_OBJECT_REFERENCES
*&
*&---------------------------------------------------------------------*
*&
*&
*&---------------------------------------------------------------------*

REPORT  ysap_object_references.

*----------------------------------------------------------------------*
*       CLASS counter DEFINITION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS counter DEFINITION.

  PUBLIC SECTION.

    METHODS: set IMPORTING value(set_value) TYPE i,
             increment,
             get EXPORTING value(get_value) TYPE i..

  PRIVATE SECTION.
    DATA: count TYPE i.

ENDCLASS.                    "counter DEFINITION

*----------------------------------------------------------------------*
*       CLASS counter IMPLEMENTATION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS counter IMPLEMENTATION.

  METHOD set.
    count = set_value.
  ENDMETHOD.                    "set

  METHOD increment.
    ADD 3 TO count.
  ENDMETHOD.                    "increment

  METHOD get.
    get_value = count.
  ENDMETHOD.                    "get

ENDCLASS.                    "counter IMPLEMENTATION




DATA: cnt_1 TYPE REF TO counter,
      cnt_2 TYPE REF TO counter,
      cnt_3 TYPE REF TO counter,
      cnt_tab TYPE TABLE OF REF TO counter.

DATA: number TYPE i.

START-OF-SELECTION.

  CREATE OBJECT: cnt_1.

  APPEND cnt_1 TO cnt_tab.


  CREATE OBJECT : cnt_2,
                  cnt_3.

  APPEND : cnt_2 TO cnt_tab,
           cnt_3 TO cnt_tab.


  CALL METHOD: cnt_1->set EXPORTING set_value = 10,
               cnt_2->set EXPORTING set_value = 100,
               cnt_3->set EXPORTING set_value = 1000.

  DO 5 TIMES.

    CALL METHOD: cnt_1->increment,
                 cnt_2->increment,
                 cnt_3->increment.
  ENDDO.

  LOOP AT cnt_tab INTO cnt_1.
    CALL METHOD cnt_1->get
      IMPORTING
        get_value = number.
    WRITE: number.
  ENDLOOP.

 Output: