Use singleton to show tree table only on HANA (#460)

Replaces #456
by using a singleton, instead of adding a property to books.

Author: beckermarc

app/admin/fiori-service.cds

@@ -37,12 +37,11 @@ annotate AdminService.Books with @(UI : {
             Label : '{i18n>Admin}',
             Target : '@UI.FieldGroup#Admin'
         },
-        {   
-            // TODO: should work dynamically
-            @UI.Hidden,
+        {
             $Type  : 'UI.ReferenceFacet',
             Label  : '{i18n>Contents}',
-            Target : 'contents/@UI.PresentationVariant'
+            Target : 'contents/@UI.PresentationVariant',
+            @UI.Hidden: { $edmJson: { $Path: '/Info/hideTreeTable' } }
         }
     ],
     FieldGroup #General : {Data : [

srv/admin-service.cds

@@ -38,6 +38,11 @@ service AdminService @(requires: 'admin') {
   entity Upload @odata.singleton {
     csv : LargeBinary @Core.MediaType: 'text/csv';
   }
+
+  @cds.persistence.skip
+  @readonly entity Info @odata.singleton {
+    hideTreeTable: Boolean;
+  }
 }
 
 // Deep Search Items

srv/src/main/java/my/bookshop/handlers/AdminServiceHandler.java

@@ -16,6 +16,7 @@
 import java.util.function.Supplier;
 import java.util.stream.Stream;
 
+import org.springframework.core.env.Environment;
 import org.springframework.stereotype.Component;
 
 import com.sap.cds.Result;
@@ -28,6 +29,7 @@
 import com.sap.cds.services.ErrorStatuses;
 import com.sap.cds.services.EventContext;
 import com.sap.cds.services.ServiceException;
+import com.sap.cds.services.cds.CdsReadEventContext;
 import com.sap.cds.services.cds.CdsUpdateEventContext;
 import com.sap.cds.services.cds.CqnService;
 import com.sap.cds.services.draft.DraftCancelEventContext;
@@ -46,6 +48,8 @@
 import cds.gen.adminservice.BooksAddToOrderContext;
 import cds.gen.adminservice.BooksCovers;
 import cds.gen.adminservice.Books_;
+import cds.gen.adminservice.Info;
+import cds.gen.adminservice.Info_;
 import cds.gen.adminservice.OrderItems;
 import cds.gen.adminservice.OrderItems_;
 import cds.gen.adminservice.Orders;
@@ -64,17 +68,16 @@
 class AdminServiceHandler implements EventHandler {
 
 	private final AdminService.Draft adminService;
-
 	private final PersistenceService db;
-
 	private final Messages messages;
-
 	private final CqnAnalyzer analyzer;
+	private final Environment env;
 
-	AdminServiceHandler(AdminService.Draft adminService, PersistenceService db, Messages messages, CdsModel model) {
+	AdminServiceHandler(AdminService.Draft adminService, PersistenceService db, Messages messages, CdsModel model, Environment env) {
 		this.adminService = adminService;
 		this.db = db;
 		this.messages = messages;
+		this.env = env;
 
 		// model is a tenant-dependant model proxy
 		this.analyzer = CqnAnalyzer.create(model);
@@ -301,6 +304,13 @@ public void restoreCoversUpId(CqnStructuredTypeRef ref, BooksCovers cover) {
 		cover.setUpId((String) analyzer.analyze(ref).rootKeys().get(Books.ID));
 	}
 
+	@On(event = CqnService.EVENT_READ, entity = Info_.CDS_NAME)
+	public Info readInfo(CdsReadEventContext context) {
+		Info info = Info.create();
+		info.setHideTreeTable(!env.matchesProfiles("cloud"));
+		return info;
+	}
+
 	private Supplier<ServiceException> notFound(String message) {
 		return () -> new ServiceException(ErrorStatuses.NOT_FOUND, message);
 	}