Fiori Tree Views towards GA (#839)

* Fiori Tree Views towards GA

* Also automate addition of Aggregation.RecursiveHierarchy

* Cleanup models for Genres Tree View

* Implementing @hierarchy shortcut

* .

* Formatting

* Using verbose config

fiori/app/genres/tree-view.cds

@@ -0,0 +1,42 @@
+using { AdminService } from '@capire/bookstore';
+
+////////////////////////////////////////////////////////////////////////////
+//
+//	Genres Tree View
+//
+
+// Tell Fiori about the structure of the hierarchy
+annotate AdminService.Genres with @Aggregation.RecursiveHierarchy #GenresHierarchy : {
+  ParentNavigationProperty : parent, // navigates to a node's parent
+  NodeProperty             : ID, // identifies a node, usually the key
+};
+
+// Fiori expects the following to be defined explicitly, even though they're always the same
+extend AdminService.Genres with @(
+  // The columns expected by Fiori to be present in hierarchy entities
+  Hierarchy.RecursiveHierarchy #GenresHierarchy : {
+    LimitedDescendantCount : LimitedDescendantCount,
+    DistanceFromRoot       : DistanceFromRoot,
+    DrillState             : DrillState,
+    LimitedRank            : LimitedRank
+  },
+  // Disallow filtering on these properties from Fiori UIs
+  Capabilities.FilterRestrictions.NonFilterableProperties: [
+    'LimitedDescendantCount',
+    'DistanceFromRoot',
+    'DrillState',
+    'LimitedRank'
+  ],
+  // Disallow sorting on these properties from Fiori UIs
+  Capabilities.SortRestrictions.NonSortableProperties    : [
+    'LimitedDescendantCount',
+    'DistanceFromRoot',
+    'DrillState',
+    'LimitedRank'
+  ],
+) columns { // Ensure we can query these fields from database
+  null as LimitedDescendantCount : Int16,
+  null as DistanceFromRoot       : Int16,
+  null as DrillState             : String,
+  null as LimitedRank            : Int16,
+};