How to change paging option of object type IF_RAP_QUERY_PAGING in runtime?

[ak4522912]

I am trying to display data in fiori elements application through custom entity CDS.

By default it was taking page size of 25 & was not showing records after that even after scrolling & page down button.

Inside the implementation of IF_RAP_QUERY_PROVIDER~SELECT method I had retrieved the paging object using IO_REQUEST->GET_PAGING method.

Then I tried downcasting it & then change the dynamic public attribute MV_HAS_PAGING from X to SPACE(INITIAL).

I was able to do the same manually through changing the attribute value in debugger, but when I am trying to do the same in code it's giving me dump of changing protected field as it's reference is coming as read-only.

Code Snippet-

method : IF_RAP_QUERY_PROVIDER~SELECT.

data(lv_page) = io_request->get_paging( ).

data: lo_ref type ref to object.

lo_ref ?= lv_page.

ASSIGN lo_ref->('MV_HAS_PAGING') to FIELD-SYMBOL(<lfs_attr>).

<lfs_attr> = abap_false.

[FredericGirod]

I didn't have your interface in my system. But, if you would like to retrieve an object reference to an interface, why did you create a generic object ?

method : IF_RAP_QUERY_PROVIDER~SELECT.
data(lv_page) = io_request->get_paging( ).
data: lo_ref type ref to if_rap_query_paging.
lo_ref ?= lv_page.

is there any method in the implementation of this interface, allow you to update the attribut without doing this terrific memory modification ?

[ak4522912]

Hi Frederic,

I initially tried changing the attribute(MV_HAS_PAGING) of lv_page which is of type IF_RAP_QUERY_PAGING but it's assignment to field symbol was failing.

So, I tried with generic object reference.

Also, I was not able to find any method which can do direct modification of that attribute.

ASSIGN lv_page->('MV_HAS_PAGING') to FIELD-SYMBOL(<lfs_attr>). "sy-subrc = 4 ( <lfs_attr> was not assigned)

[FredericGirod]

it is difficult to help you without full access to interface & class.

1. Did you check if the class is related to several interface ? maybe another interface could do it

2. Did you try the "local friend" ?

[abo]

If it is a protected field, it might be that you're not supposed to change it.

Also, if there is no method in the interface to change that value it is quite possible that it is only meant as an information: there is paging vs there is none.

[ak4522912]

Hi Frederic & Andrea,

• I tried other classes like but still assignment of dynamic public instance attribute 'MV_HAS_PAGING' was failing. It was only working with generic object reference & in that case it was read only data, so wasn't able to change it.
• It is a public field & I am able to change it in debugging mode but not via ABAP program( <lfs_attr> is coming as read only). If it is editable in debug mode I think there should be a way to the same though program.

[ak4522912]

Attachments

[FredericGirod]

if it is public, why didn't you try.

lv_page=>mv_has_paging = abap_false.

[ak4522912]

Because it is a dynamically generated attribute & is only available at runtime not during activation.

[ak4522912]

Attachment

[FredericGirod]

I think I start to understand 🙂 take me long time 🙂

data(lv_page) = io_request->get_paging( ).
data: lo_ref type ref to lcl_rap_query_paging.
lo_ref ?= lv_page.
ASSIGN lo_ref->('MV_HAS_PAGING') to FIELD-SYMBOL(<lfs_attr>).
<lfs_attr> = abap_false.

because you are trying to do this :

https://help.sap.com/doc/abapdocu_752_index_htm/7.52/en-US/abenclass_components_addressing.htm

and the attribute is present only in class not in interface (so big dependency)

[Sandra_Rossi]

Instead of tweaking the standard, as explained here Interface IF_RAP_QUERY_PAGING - SAP Help Portal, this property can be changed by using "the query option $top". (https://yourfioriapp...?$top=50)

Now, your issue is not about changing the size, it's about scrolling, as you say: "By default it was taking page size of 25 & was not showing records after that even after scrolling & page down button."

The first time Fiori app displays with data, are you sure your SELECT returns 25 rows and not 24 or less?

When you scroll, does the debugger stops at SELECT?

[ak4522912]

Hi Sandra,

Initially I didn't put any restrictions on total no of output records. I passed all the records. But it was throwing a dump because it was comparing total no of records with page size in standard code. Offset was coming as 0 & page size as 25.

Number of records which I intended to pass was ~20K. So, then I tried limiting records using offset & page size. After that only first 25 records were showing in output & when I tried to scroll down or use page down button it didn't hit my method or breakpoint again. In short it was only executing for the first time after that it was not hitting or executing select/method.

[ShishirP]

Hello ak4522912,

                            Did you find the solution for this issue? I am facing the same issue. I end with 30 records and scrolling does not trigger the debugger means the selection is not triggering.

Regards,

Shishir. P

[Erol_CAGLAR]

Hi FredericGirod

How to implemented lcl_rap_query_paging I tried copy from cl_rap_query_paging , but can not allowed to casting? can you share it

data(lv_page) = io_request->get_paging( ). data: lo_ref type ref to lcl_rap_query_paging. lo_ref ?= lv_page. ASSIGN lo_ref->('MV_HAS_PAGING') to FIELD-SYMBOL(<lfs_attr>). <lfs_attr> = abap_false.

[rkenjiibmsuser]

Hi ak4522912!

Did you find a solution? I'm facing same problem.

[dominikeiraelias]

Hi Amit,

the IF_RAP_QUERY_REQUEST, PAGING and any other API object must not be changed!

The consumer is sending a certain request and your implementation has two options: You are either able to process the request and send a response accordingly or you can raise an exception as declared in IF_RAP_QUERY_PROVIDER~SELECT to state that you were not able to handle the request according to the OData and unmanaged query contract. Changing attributes or replacing the objects will lead to runtime errors as the orchestration framework makes sure that those stay untouched and data is returned accordingly.

If you want to select more or less data please configure your application consuming data from your unmanaged query accordingly. OData offers a variety of query options to request the data as needed. $top and $skip can be used to select data in packages and those will be reflected in the paging.

Best regards,

Dominik

[ak4522912]

Hi Dominic,

Thanks for your response. I agree that API objects shouldn't be changed. I only tried to do this as the last resort. When I created my fiori list(elements) app by using the binding of my custom entity as a data source, I was unable to change the paging option from front end by doing changes in maifest.json file.

I tried using adaption project also to change paging option but it didn't work. Paging option was still enabled and page size was coming as 25 so only top 25 records were displayed. Rest of the records were not displayed even after scrolling or pressing page down button.

During debugging I disabled paging(attribute MV_HAS_PAGING inside IF_RAP_QUERY_PROVIDER~SELECT) manually & it worked( all records were displayed) but wasn't able to do that via ABAP code.

As my front end is based on fiori elements, I think it will not be possible to use Odata query with $top & $skip.

Please suggest if there is any other way or workaround to show all data ( ~20k records) in my fiori application via custom entity.

Regards,

Amit Kumar

[dominikeiraelias]

Hi Amit,

it is in the responsibility of the consumer/client to request data as they need it. Your backend implementation should not alter a request and only provide what has been requested.

Fiori Elements Apps in the end also just generate OData requests. Smart Template Applications do that correctly and if you have implemented a custom fiori app, than it might be that you have to do some frontend coding. Maybe this is helpful for you: https://blogs.sap.com/2014/11/19/sapui5-pagination-in-sapmtable-using-skip-and-top-values-of-odata-s...

Regards,
Dominik