In a RAP application, you usually expose business objects and services as OData APIs (consumed by Fiori apps or external systems).
Every business object instance (like Complaint, Sales Order, Request) needs a unique identifier (key field).

• In SAP GUI-based classic apps, we often set the key in a TMG or via SNRO config.

• In RAP, we don’t rely on GUI transactions → instead, we need to generate the ID programmatically when a new entity is created via the service.

That’s exactly what this class is doing:
👉 It creates a Number Range Object, sets up its intervals, and provides a method to fetch the next number.
So in a RAP app, you’d call this class (e.g., get_number) when you handle the CREATE operation of an entity.

CLASS zcl_numrng_demo DEFINITION
PUBLIC FINAL
CREATE PUBLIC.

PUBLIC SECTION.
INTERFACES if_oo_adt_classrun.

PRIVATE SECTION.
CONSTANTS gc_obj_id TYPE cl_numberrange_objects=>nr_attributes-object VALUE ‘ZNR_DEMO’.
CONSTANTS gc_package TYPE cl_numberrange_objects=>nr_attributes-devclass VALUE ‘ZDEMO_PKG’.
CONSTANTS gc_transport TYPE cl_numberrange_objects=>nr_attributes-corrnr VALUE ”.

METHODS create_obj
IMPORTING io_console TYPE REF TO if_oo_adt_classrun_out.

METHODS create_interval
IMPORTING io_console TYPE REF TO if_oo_adt_classrun_out.

METHODS get_number
IMPORTING io_console TYPE REF TO if_oo_adt_classrun_out.
ENDCLASS.

CLASS zcl_numrng_demo IMPLEMENTATION.
METHOD if_oo_adt_classrun~main.
create_obj( out ).
create_interval( out ).
get_number( out ).
ENDMETHOD.

METHOD create_obj.
TRY.
cl_numberrange_objects=>create(
EXPORTING attributes = VALUE #( object = gc_obj_id
domlen = ‘ZNR_DEMO_DOM’
percentage = 5
devclass = gc_package
corrnr = gc_transport )
obj_text = VALUE #( langu = ‘E’
object = gc_obj_id
txtshort = ‘Demo Numbers’
txt = ‘Demo Number Range Object’ )
IMPORTING errors = DATA(lt_err)
returncode = DATA(lv_ret) ).
CATCH cx_number_ranges INTO DATA(lo_ex).
io_console->write( lo_ex->get_text( ) ).
ENDTRY.

io_console->write( lt_err ).
io_console->write( lv_ret ).
ENDMETHOD.

METHOD create_interval.
TRY.
cl_numberrange_intervals=>create(
EXPORTING interval = VALUE #(
( nrrangenr = ’01’
fromnumber = ‘500000’
tonumber = ‘599999’
procind = ‘I’ ) )
object = gc_obj_id
IMPORTING error = DATA(lv_err)
error_inf = DATA(ls_err)
error_iv = DATA(lt_err_iv)
warning = DATA(lv_warn) ).

CATCH cx_root INTO DATA(lo_ex).
io_console->write( lo_ex->get_text( ) ).
ENDTRY.

io_console->write( lv_err ).
io_console->write( ls_err ).
io_console->write( lt_err_iv ).
io_console->write( lv_warn ).
ENDMETHOD.

METHOD get_number.
TRY.
cl_numberrange_runtime=>number_get(
EXPORTING nr_range_nr = ’01’
object = gc_obj_id
IMPORTING number = DATA(lv_num)
returncode = DATA(lv_rc) ).

CATCH cx_root INTO DATA(lo_ex).
io_console->write( lo_ex->get_text( ) ).
ENDTRY.

io_console->write( lv_num ).
io_console->write( lv_rc ).
ENDMETHOD.
ENDCLASS.