interface

*&---------------------------------------------------------------------*
*& report zdemo05
*&---------------------------------------------------------------------*
*&
*&---------------------------------------------------------------------*
REPORT z_interface.

INTERFACE status.
  METHODS write.
ENDINTERFACE.

CLASS counter DEFINITION.
  PUBLIC SECTION.
    INTERFACES status.

    METHODS increment.

  PRIVATE SECTION.
    DATA count TYPE i.
ENDCLASS.

CLASS counter IMPLEMENTATION.
  METHOD status~write.
    cl_demo_output=>write_text( |count in counter is { count } | ).
  ENDMETHOD.

  METHOD increment.
    count = count + 1.
  ENDMETHOD.
ENDCLASS.

CLASS bicycle DEFINITION.
  PUBLIC SECTION.
    INTERFACES status.

    METHODS drive.
  PRIVATE SECTION.
    DATA speed TYPE i.
ENDCLASS.

CLASS bicycle IMPLEMENTATION.
  METHOD status~write.
    cl_demo_output=>write_text( |speed of bicycle is { speed } | ).
  ENDMETHOD.

  METHOD drive.
    speed = speed + 10.
  ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.
  DATA(count) = NEW counter( ).
  DATA(bike) = NEW bicycle( ).

  DO 5 TIMES.
    count->increment( ).
    bike->drive( ).
  ENDDO.

  count->status~write( ).
  bike->status~write( ).

  DATA status_tab TYPE TABLE OF REF TO status WITH EMPTY KEY.

  status_tab = VALUE #( ( count )
                        ( bike ) ).

  LOOP AT status_tab ASSIGNING FIELD-SYMBOL(<status>).
    <status>->write( ).
  ENDLOOP.
  cl_demo_output=>display( ).