topic Re: Friend Class in Application Development and Automation Discussions

Friend Class

karthikeyan_m4 — Wed, 26 May 2010 07:42:55 GMT

I want to access private methods using friend class...

For example

CLASS C1 DEFINITION.

PUBLIC SECTION.

METHODS : M1.

PRIVATE SECTION.

METHODS: M2.

ENDCLASS.

CLASS C1 IMPLEMENTATION.

METHOD M1.

WRITE : 'Public Method C1'.

ENDMETHOD.

METHOD M2.

WRITE : 'Private Method C1'.

ENDMETHOD.

ENDCLASS.

CLASS C2 DEFINITION CREATE PRIVATE FRIENDS C1.

PUBLIC SECTION.

METHODS : M3.

ENDCLASS.

CLASS C2 IMPLEMENTATION.

METHOD M3.

data : obj TYPE REF TO C1.

create OBJECT obj.

CALL METHOD obj->M2. " Error says access to M2 is not allowed

WRITE 'Public Method C2'.

ENDMETHOD.

ENDCLASS.

Pllz help...

thanks

Karthikeyan

Re: Friend Class

MarcinPciak — Wed, 26 May 2010 08:01:36 GMT

It is class C1 which has to declare friendship to class C2 in order C2 can access C1's private components, not vice versa.

I.e I say John is my friend (I therefore allow him to play my PS3;) ). John does not like me so much (a pitty:( ) so he doesn't allow me ride his bike.

So what you need is


CLASS c2 DEFINITION DEFERRED.

CLASS c1 DEFINITION FRIENDS c2.
  PUBLIC SECTION.
    METHODS : m1.
  PRIVATE SECTION.
    METHODS: m2.
ENDCLASS.                  


CLASS c1 IMPLEMENTATION .
  METHOD m1.
    WRITE : 'Public Method C1'.
  ENDMETHOD.                    "M1
  METHOD m2.
    WRITE : 'Private Method C1'.
  ENDMETHOD.                    "M2
ENDCLASS.                    


CLASS c2 DEFINITION FRIENDS c1.  "my friends are here, allow them access to my (C2's) private components
  PUBLIC SECTION.
    METHODS : m3.
ENDCLASS.              


CLASS c2 IMPLEMENTATION.
  METHOD m3.
    DATA : obj TYPE REF TO c1.
    CREATE OBJECT obj.
    CALL METHOD obj->m2.    "now I am able to call his method, as he says I am his friend
    WRITE 'Public Method C2'.
  ENDMETHOD.                    "M3
ENDCLASS.                   

START-OF-SELECTION.
  DATA obj_c2 TYPE REF TO c2.

  CREATE OBJECT obj_c2.
  obj_c2->m3( ).

Regards

Marcin

Re: Friend Class

hubert_heitzer — Wed, 26 May 2010 08:07:20 GMT

Hi Karthikeyan,

friendship can only be declared in the class which allows friendship.

In your example class C1 has to declare class C2 as a friend.

If friendship could be declared like you tried, it would be very easy to break up an encapsulation.

Regards, Hubert

Re: Friend Class

Former Member — Tue, 12 Apr 2011 06:00:14 GMT

This was really awesome!!!!!