topic Re: ooabap object creation in Application Development and Automation Discussions

ooabap object creation

former_member1241090 — Tue, 17 Aug 2021 12:11:02 GMT

Can we create an object for private class

Re: ooabap object creation

Sandra_Rossi — Tue, 17 Aug 2021 12:13:44 GMT

I never heard of "private class" concept in ABAP. Can you explain what you mean?

Re: ooabap object creation

former_member598787 — Tue, 17 Aug 2021 14:13:16 GMT

Hello,

Information provided is not sufficient.

But still, by private instantiation of class , This is something you can achieve by using SINGLETON class .(ABAP design patterns) , You can find examples of singleton classes on google.

Re: ooabap object creation

matt — Tue, 17 Aug 2021 17:52:39 GMT

Yes, but only from that class or a friend of that class.

Re: ooabap object creation

matt — Tue, 17 Aug 2021 17:54:41 GMT

Other examples are enumeration classes where a public read-only structure holds self-references, and factory classes where the classes they return are all friends of the factory class. In this way the ability to instantiate is entirely controlled.

Re: ooabap object creation

FredericGirod — Wed, 18 Aug 2021 05:42:53 GMT

A private class should (must) avec have a public method to create the instance : Get_Instance( ) or something like that

Re: ooabap object creation

FredericGirod — Wed, 18 Aug 2021 05:47:03 GMT

sandra.rossi

CLASS ZCL_MyBeautifullClass DEFINITION
  PUBLIC
  FINAL
  CREATE PRIVATE.   <--


  PUBLIC SECTION.
    INTERFACES zif_MyBeautifullInterface
    METHODS CONSTRUCTOR.
    METHODS GET_INSTANCE 
      RETURNING VALUE(o_instance) TYPE REF TO zif_MyBeautifullInterface.
ENDCLASS.



CLASS zcl_MyBeautifullInterface IMPLEMENTATION.
  METHOD constructor.
    ...
  ENDMETHOD.


  METHOD get_instance.
    o_instance = new zcl_mybeautifullclass( ).
  endmethod.
ENDCLASS.

You cannot call the constructor from outside. You can only call get_instance, and get_instance will call the constructor.

Re: ooabap object creation

matt — Wed, 18 Aug 2021 05:47:29 GMT

frdric.girod a public class/static method. But not always.

An example of a private class without a public method, https://github.com/SAP/styleguides/blob/main/clean-abap/CleanABAP.md#prefer-enumeration-classes-to-constants-interfaces

The second one.

Re: ooabap object creation

FredericGirod — Wed, 18 Aug 2021 05:49:16 GMT

yes ! constant class also use it

Re: ooabap object creation

Sandra_Rossi — Wed, 18 Aug 2021 06:24:44 GMT

frdric.girod Thanks. Yes I know that 🙂 I just meant that "private class" is not an official term (although I see the term appears once in the official ABAP documentation - in CREATE OBJECT). With a so much general question in 8 words, I'm not sure the person understands the whole topic, so I try to make her speak more about it. The term "class with private instantiation" or "privately instantiated" would be better suited. The term "private class" makes me think that we are talking about package check: a class which cannot be seen/used by objects of other packages.

Re: ooabap object creation

FredericGirod — Wed, 18 Aug 2021 06:46:46 GMT

sandra.rossi I wrote this big example for you, before my coffee, and you already know it ... 🙂

Re: ooabap object creation

former_member697514 — Wed, 18 Aug 2021 12:57:15 GMT

Hi Rajani,

yes we can create object for private class ( within same class)

if we try to create object in sub class error will be thrown.

so if we want to create object of parent class(private class) in sub class then we have to use friend class concept as shown in below image.

and you can also achieve using singleton class.

Re: ooabap object creation

Shruthi2979 — Mon, 24 Jan 2022 11:33:25 GMT

Hi ,

Yes we can create the object for the private class .

We can also create the object for the friends class which is the friend of the private class.

Thanks.