1. Start maintaining the model provider extension class ZCL_ZGW_PRODUCT_MPC_EXT

2. Redefine the DEFINE method of the MPC_EXT class

method DEFINE.
  super->define( ).
  model->set_soft_state_enabled( abap_true ).
endmethod.

Attribute
MV_IS_SOFTSTATE

Level
Instance Attribute

Visibility
Private

Typing
Type

Associated Type
ABAP_BOOL

Description
TRUE if we are running in softstate mode

Click on the Methods tab and redefine the method /IWBEP/IF_MGW_SOST_SRV_RUNTIME~OPERATION_START

and enter the following line of code

mv_is_softstate = abap_true.

  method /IWBEP/IF_MGW_SOST_SRV_RUNTIME~OPERATION_START.

  mv_is_softstate = abap_true.

  endmethod.

Now click on the Methods tab and redefine the method /IWBEP/IF_MGW_SOST_SRV_RUNTIME~OPERATION_END

without entering any code.

Please note:
Without activating both methods you would get an exception

Now define a second (static) attribute GV_COUNT of type I to demo the use of soft state

Click on the Attributes tab and insert a new attribute with the following settings:

Attribute
GV_COUNT

Level
Static Attribute

Visibility
Protected

Typing
Type

Associated Type
I

Description
Store counter

Navigate back to the Service Builder and expand the folder Service Maintenance.

Expand the folder Maintain.

Right click on the entry of your Gateway Hub system  to start the transaction /IWFND/MAINT_SERVICE with filtered for your service name

You will notice that the service ZGW_PRODUCT_SRV is shown as not supporting Soft-State.

If you click on the Soft-State button (1) you will get an error message

Click on Load Metadata and confirm the sucess message

The service is now shown such  that it supports soft state but soft state is not yet activated.

Hint:

If the service is not shown as inactive try to clear the metadata cache in the Gateway Hub as well as in the Gatebay backend system. To do so:

1. Start transaction /IWBEP/CACHE_CLEANUP in the backend and activate the check box Cleanup Cache for all Models.
2. Start transcation /iwfnd/cache_cleanup on the hub and run it with the check box Cleanup Cache for all Models.

Change the implementation of the method  PRODUCTSET_GET_ENTITYSET to enable a custom counter when $count is called for the entity set ProductSet with the coding shown on the right.

The coding first checks whether /$count is requested and has implemented a custom implementation to retrieve $count.

If soft state is not enabled the number of products will be retrieved by counting the table entries in SNWD_PD.

If soft state is enabled the code checks whether the member variable GV_COUNT is inital.

If it is initial that means if the /$count is called for the first time in this session we have to retrieve the number of entries from the database.

Only if /$count is called a second time when soft state is enabled no data will be read from the database and /$count will rather be filled with the value stored in the variable GV_COUNT which is then incremented by 1 to show you that soft state is actually working.

If the time configured as a session timeout is exceeded counting starts again from the number of products which is equal to the number of table entries in table SNWD_PD.

method PRODUCTSET_GET_ENTITYSET.

DATA lv_count_requested TYPE abap_bool.

lv_count_requested = io_tech_request_context->has_count( ).

IF lv_count_requested EQ abap_true.

  IF  mv_is_softstate = abap_false.

    SELECT COUNT( * ) INTO gv_count FROM SNWD_PD.

  ELSE.

    if gv_count is INITIAL.

      SELECT COUNT( * ) INTO gv_count FROM SNWD_PD.

    ELSE.

      gv_count = gv_count + 1.

    ENDIF.

  ENDIF.

  es_response_context-count = gv_count.

ELSE.

  CALL FUNCTION 'BAPI_EPM_PRODUCT_GET_LIST'

* EXPORTING

*  MAX_ROWS                    =

  TABLES

      HEADERDATA                  = et_entityset
*  SELPARAMPRODUCTID          =
*  SELPARAMSUPPLIERNAMES      =
*  SELPARAMCATEGORIES          =
*  RETURN                      =
          .

ENDIF.

ENDMETHOD.

Call your service via the browser.

Start a performance trace using /IWFND/TRACES.

Perform several requests with $count having soft state enabled

We can see that the initial request takes 16 milliseconds in the backend (GW framework overhead + Application Data Provider response time).

For every subsequent request  the Application Data Provider Response time is zero and the GW framework overhead is reduced to 5 mill seconds.

The result now is that subsequent requests have the same response time.

The response time is the same that we got for the first initial request when soft state was enabled.