ABAP_to_the_Future

13
SAPUI5
The purpose of the GET_ENTITY_SET method is to pass back a list of all the entities
(monsters) that have been requested by an incoming URL. As can be seen in Listing
13.2, first you start dealing with instructions that have been passed in to the
method (from the URL), such as the sort order (like the SORTCAT table in the ALV),
which is here stored in LT_SORTORDER, then the selection options, and finally
some more obscure things, like paging.
In regard to the selection options, they’re listed in the URL in the form of a string,
but the handler class in the SICF service no de transforms this into the form of a
table of selections ( IT_FILTER_SELECT_OPTIONS), which is passed into the GET_
ENTITY_SET method. Translate that selection table into the format that your monster
model class data retrieval method li kes, and then delegate getting the actual
data to the monster model method RETRIEVE_HEADERS_BY_ATTRIBUTE.
One you have the data, check if the incoming URL requested the data to be sorted
in a particular order. If so, then build up a dynamic table to sort the retrieved
data. Now check to see if the incoming URL specified that you only bring back
certain lines (e.g., the first 10 rows of the table).
Next, an export table is fi lled up with all the entities (monster headers) that you
want to send back to the caller. Right at the end is some code to enable testing
using Eclipse.
Warning: Houston, We Have a Problem
Often, you try and test your application an d get the screen but no data due to something
called CORS (Cross Origin Resource Sharing). Adding the preceding call to set
header solves the SAP Gateway (server) side of the equation. The local device (client)
settings needed will be discussed in Section 13.4.3.
METHOD monsterset_get_entityset.
* Extract any instructions as to how to sort the result list from
* the incoming request
DATA: lt_techorder TYPE /iwbep/t_mgw_tech_order,
lt_sortorder TYPE abap_sortorder_tab.
IF io_tech_request_context IS BOUND.
lt_techorder = io_tech_request_context->get_orderby( ).
ENDIF.
* See if we have any selection criteria passed in
* We adapt the ODATA structure to the BOPF selection structure
DATA: ls_filter_select_options
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