topic Re: abap objects and selection screen in Application Development and Automation Discussions

abap objects and selection screen

Former Member — Tue, 04 May 2010 15:40:16 GMT

Hello everybody,

I am interested in your ways of implementing selection-screens in the style of ABAP Objects.

In earlier times (when I used to implement ABAP objects in a procedural way) I just put the selection-screen commands in an include or a form routine of my ABAP report. So it was possible to run the report in background.

Now I read something about selection-screens/dynpros and "separation of concerns" in the book "ABAP Objects" written by Keller. He advises using function groups to encapsulate presentation from logical matters. (Selection-screen commands are in an automatically generated include now). I implemented this way. (ABAP report with a local class, which has a main method, where function module of the function group is called). It works, but i see no chance to run my report in background now.. but I need to run the report in background.

Does anybody know a solution without deleting function group?

What do you think is the best way of using selection-screen-commands and ABAP Objects, especially regarding running in background?

Thx for your advise in advance.

Kind regards,

Anne

Re: abap objects and selection screen

naimesh_patel — Tue, 04 May 2010 16:04:34 GMT

I prefer to create an executable Report program when I have to create Selection Screen.

To achieve the separation of concerns or MVC, I create a class for the Selection screen attribute, a MAIN class which act as the controller (as C of the MVC) along with the Report itself. I also create a DATA class ( as M of the MVC) which contains my actual data selection and processing. If I have to generate the File (as V of the MVC), I create the class for the File Handling. If I have to generate the output as ALV, I create the class for ALV. I reference Data class, Selection class and ALV class in the MAIN class (act as Facade). I also reference the Selection screen object to DATA class.

In the report program, I basically instantiate facade (ref to MAIN) which in-turn instantiate all your objects. In the START-OF-SELECTION, I set all the Attributes from the selection screen to selection screen object. Based on the requirement, I get the data by calling the GET_DATA method of the Facade which calls the methods of the Data Class.

Regards,

Naimesh Patel

Re: abap objects and selection screen

Sandra_Rossi — Tue, 04 May 2010 16:45:52 GMT

> but i see no chance to run my report in background now.. but I need to run the report in background.

you must still use the classic reports to run in background (but maybe there is a standard "submitter report" with program and variant in selection screen, so that you don't need to create your own submitter report)

Re: abap objects and selection screen

Former Member — Wed, 05 May 2010 09:12:02 GMT

Hi Naimesh,

thx for explanation. I am not sure, if I understood everything in the right way.

Where do you write the code for building the selection-screen? (PARAMETERS, SELECT-OPTIONS etc.)

If you write these commands in a class method, you will get a syntax error ( because it's forbidden per definition of ABAP objects). So, am I right assuming that you put the coding just at the beginning of the ABAP report ? And after START-OF-SELECTION-event you start the processing... ?

Furthermore, I don't really understand why you create an separate class for ALV. I found your "SAP abap help"-blog, where you explained the concept of MVC ((By the way, well done!), but you didn't mention an "ALV class" there..

Mh.. another question - have you ever combined MVC with object services?

At the moment I'm working on a software project where I use object services. I created 2 persistent classes via SE24 and one local class in my ABAP Report.

I don't really see possibility to implement MVC in this project without change very much of coding and class structure...

In my opinion the M (data&business logic) are my existing global classes and my local class is kind of Controller class?!

Thx in advance,

Anne

Re: abap objects and selection screen

Former Member — Wed, 05 May 2010 09:15:30 GMT

Hi Sandra,

I still use a standard report, but with a local class. The point is, that I'm unsure about positioning the selection-screen-commands.. that's why I tried to use function groups..

> you must still use the classic reports to run in background (but maybe there is a standard "submitter report" with program and variant in selection screen, so that you don't need to create your own submitter report)

I didn't get your idea.. what kind of "submitter report" do you mean?

Thx,

Anne

Re: abap objects and selection screen

Sandra_Rossi — Wed, 05 May 2010 09:41:41 GMT

Well, I think I must have smoken marijuana or something, as you can simply submit your main program in background

A very simplified report could look like that:


REPORT Z_ABAPOO_SELSCR.

parameters param1.

CLASS lcl_any DEFINITION.
public section.
class-methods processing importing param type any.
ENDCLASS.

START-OF-SELECTION.
call method lcl_any=>processing exporting param = param1.

CLASS lcl_any IMPLEMENTATION.
METHOD processing.
  CALL FUNCTION 'Z_ANY'
        EXPORTING param = param.
ENDMETHOD.
ENDCLASS.

Re: abap objects and selection screen

Former Member — Wed, 05 May 2010 09:52:39 GMT

@Sandra

this is exactly how I implemented the approach with the function module.

So, in the function module I call my selection-screen with CALL SELECTION-SCREEN command, which opens the automatically generated include, where I put my selection-screen commands.

But if I do it like that, I won't be able to run the report in background because the variants don't belong to my ABAP report then, but to the automatically generated include part.

Do you know a solution for that?

Thx.

Re: abap objects and selection screen

Sandra_Rossi — Wed, 05 May 2010 09:56:44 GMT

you must put all parameters in Z_ABAPOO_SELSCR, and pass them to class and function module. You don't need to put a selection screen in the function module.

Re: abap objects and selection screen

Former Member — Wed, 05 May 2010 10:04:59 GMT

@Sandra

ah..sorry..my fault. I just overlooked your "parameter command"..

Mh, okay, but if I put selection-screen commands at the beginning of the ABAP report, I don't need the function module call anymore. Or for what purpose did you use the function module?

Re: abap objects and selection screen

Sandra_Rossi — Wed, 05 May 2010 11:29:36 GMT

A selection screen used for passing parameters to a report in background can't be written using abap object. The book did only refer to real screen logic, which is not the case here.