Update README.md

Author: oblomov-dev

README.md

@@ -1,2 +1,80 @@
 # abap2UI5-btp_proxy_kpi
-Integrate KPIs for abap2UI5 Apps to SAP Business Technology Platform
+🚧 work in progress 🚧
+<br><br>
+Find a way to send KPIs from ABAP to BTP. <br>
+Maintain KPIs for abap2UI5 apps integrated in SAP Build Launchpad Service.
+<br>
+<br>
+#### Approach / First Idea:
+(1/3) Use a single Interface:
+```abap
+INTERFACE z2ui5_if_proxy_kpi
+  PUBLIC.
+
+  METHODS count
+    IMPORTING
+      filter           TYPE string
+    RETURNING
+      VALUE(result) TYPE i.
+
+ENDINTERFACE.
+```
+(2/3) Which can be used on app level to return KPIs:
+```abap
+CLASS z2ui5_cl_proxy_kpi_hello_world DEFINITION
+  PUBLIC
+  FINAL
+  CREATE PUBLIC .
+
+  PUBLIC SECTION.
+    INTERFACES z2ui5_if_proxy_kpi.
+    INTERFACES z2ui5_if_app.
+
+ENDCLASS.
+CLASS z2ui5_cl_proxy_kpi_hello_world IMPLEMENTATION.
+
+  METHOD z2ui5_if_proxy_kpi~count.
+
+    "app level calculation....
+    result = 11.
+
+  ENDMETHOD.
+
+  METHOD z2ui5_if_app~main.
+        "abap2UI5 app logic here...
+  ENDMETHOD.
+
+ENDCLASS.
+```
+(3/3) The rest handles an OData service (Dummy retunring n table entries):
+```abap
+  METHOD /iwbep/if_mgw_appl_srv_runtime~get_entityset.
+
+    DATA lt_result TYPE zcl_z2ui5_proxy_kpi_mpc=>tt_entity.
+    DATA(lt_filter_cond) = io_tech_request_context->get_filter( )->get_filter_select_options( ).
+
+    TRY.
+        DATA(lv_classname)   = to_upper( lt_filter_cond[ property = `CLASS` ]-select_options[ 1 ]-low ).
+      CATCH cx_root.
+        INSERT VALUE #( id = `ERROR_NO_PARAMETER_FOUND_WITH_NAME_CLASS` ) INTO TABLE lt_result.
+        copy_data_to_ref( EXPORTING is_data = lt_result CHANGING cr_data = er_entityset ).
+        RETURN.
+    ENDTRY.
+
+    TRY.
+        DATA(lv_filter) = to_upper( lt_filter_cond[ property = `FILTER` ]-select_options[ 1 ]-low ).
+      CATCH cx_root.
+    ENDTRY.
+
+    DATA li_proxy_kpi TYPE REF TO z2ui5_if_proxy_kpi.
+    CREATE OBJECT li_proxy_kpi TYPE (lv_classname).
+    DATA(lv_count) = li_proxy_kpi->count( lv_filter ).
+
+    DO lv_count TIMES.
+      INSERT VALUE #( id = sy-index ) INTO TABLE lt_result.
+    ENDDO.
+
+    copy_data_to_ref( EXPORTING is_data = lt_result CHANGING cr_data = er_entityset ).
+
+  ENDMETHOD.
+```