Concept of Interface in ABAP OOP

REPORT  zcl_oops_test1.


*----------------------------------------------------------------------*
*       INTERFACE intf
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
INTERFACE intf.
  METHODS details.
ENDINTERFACE.                    "intf

*----------------------------------------------------------------------*
*       CLASS cl_test DEFINITION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS cl_test DEFINITION.
  PUBLIC SECTION.
    INTERFACES intf.
    METHODS address.
  PRIVATE SECTION.
    DATA ph_no TYPE i.
ENDCLASS.                    "cl_test DEFINITION

*----------------------------------------------------------------------*
*       CLASS cl_test IMPLEMENTATION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS cl_test IMPLEMENTATION.
  METHOD intf~details.
    WRITE: / 'Name - Sandhya, Ph No - ', ph_no.
  ENDMETHOD.                    "intf~details
  METHOD address.
    ADD 12345 TO ph_no.
  ENDMETHOD.                    "Address
ENDCLASS.                    "cl_test IMPLEMENTATION

*----------------------------------------------------------------------*
*       CLASS cl_test1 DEFINITION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS cl_test1 DEFINITION.
  PUBLIC SECTION.
    INTERFACES intf.
    METHODS location.
  PRIVATE SECTION.
    DATA distance TYPE i.
ENDCLASS.                    "cl_test1 DEFINITION

*----------------------------------------------------------------------*
*       CLASS cl_test1 IMPLEMENTATION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS cl_test1 IMPLEMENTATION.
  METHOD intf~details.
    WRITE: / 'Location - PSN, City - Bangalore, Distance from Home - ',distance.
  ENDMETHOD.                    "intf~details
  METHOD location.
    ADD 30 TO distance.
  ENDMETHOD.                    "location
ENDCLASS.                    "cl_test1 IMPLEMENTATION

DATA: ph_no1  TYPE REF TO cl_test,
      distance1  TYPE REF TO cl_test1,
      intf1 TYPE REF TO intf,
      intf_tab TYPE TABLE OF REF TO intf.

START-OF-SELECTION.

  CREATE OBJECT: ph_no1, distance1.


  CALL METHOD: ph_no1->address,
               distance1->location.


  APPEND: ph_no1 TO intf_tab,
          distance1  TO intf_tab.

  LOOP AT intf_tab INTO intf1.
    CALL METHOD intf1->details.
  ENDLOOP.

Output