CAUSEWAY-3985: [v2] Backport Table Column Sorting to be only enabled if

Comparable

Task-Url: https://issues.apache.org/jira/browse/CAUSEWAY-3985

Author: andi-huber

core/metamodel/src/main/java/org/apache/causeway/core/metamodel/spec/ObjectSpecification.java

@@ -457,6 +457,18 @@ default boolean isPrimitive() {
     default boolean isAbstract() {
         return getBeanSort().isAbstract();
     }
+    
+    /**
+    * Whether {@link #getCorrespondingClass()} implements {@link Comparable}
+    * or has ordering (primitives, strings and enums).
+    */
+    default boolean isComparableOrOrdered() {
+        var cls = getCorrespondingClass();
+        return Comparable.class.isAssignableFrom(cls)
+                || cls.isPrimitive()
+                || cls.equals(String.class)
+                || cls.isEnum();
+    }
 
     /**
      * Includes abstract types that have {@link EntityFacet}.

viewers/wicket/ui/src/main/java/org/apache/causeway/viewer/wicket/ui/components/collectioncontents/ajaxtable/CollectionContentsAsAjaxTablePanel.java

@@ -20,6 +20,7 @@
 
 import java.util.List;
 import java.util.Objects;
+import java.util.Optional;
 
 import org.apache.causeway.commons.internal.collections._Lists;
 import org.apache.causeway.core.config.CausewayConfiguration.Viewer.Wicket;
@@ -179,13 +180,16 @@ private void addPropertyColumnsIfRequired(final List<GenericColumn> columns) {
     private SingularColumn createSingularColumn(final OneToOneAssociation property) {
         val collectionModel = getModel();
         final String parentTypeName = property.getDeclaringType().logicalTypeName();
+        final Optional<String> sortable = property.getElementType().isComparableOrOrdered()
+	        ? Optional.of(property.getId())
+	        : Optional.empty(); /*not sortable*/
 
         return new SingularColumn(
         		collectionModel.getElementType(),
                 collectionModel.getVariant(),
                 Model.of(property.getCanonicalFriendlyName()),
                 property.getId(),
-                property.getId(),
+                sortable,
                 parentTypeName,
                 property.getCanonicalDescription());
     }
@@ -199,7 +203,6 @@ private PluralColumn createPluralColumn(final OneToManyAssociation collection) {
                 collectionModel.getVariant(),
                 Model.of(collection.getCanonicalFriendlyName()),
                 collection.getId(),
-                collection.getId(),
                 parentTypeName,
                 collection.getCanonicalDescription(),
                 // future work: can hook up with global config

viewers/wicket/ui/src/main/java/org/apache/causeway/viewer/wicket/ui/components/collectioncontents/ajaxtable/columns/PluralColumn.java

@@ -66,12 +66,11 @@ public PluralColumn(
     		final ObjectSpecification elementType,
             final EntityCollectionModel.Variant collectionVariant,
             final IModel<String> columnNameModel,
-            final String sortProperty,
             final String propertyId,
             final String parentTypeName,
             final Optional<String> describedAs,
             final RenderOptions opts) {
-        super(elementType, collectionVariant, columnNameModel, sortProperty, propertyId, parentTypeName, describedAs);
+        super(elementType, collectionVariant, columnNameModel, null /*never sortable*/, propertyId, parentTypeName, describedAs);
         this.opts = opts;
     }
 

viewers/wicket/ui/src/main/java/org/apache/causeway/viewer/wicket/ui/components/collectioncontents/ajaxtable/columns/SingularColumn.java

@@ -40,11 +40,11 @@ public SingularColumn(
     		final ObjectSpecification elementType,
             final EntityCollectionModel.Variant collectionVariant,
             final IModel<String> columnNameModel,
-            final String sortProperty,
             final String propertyId,
+            final Optional<String> sortable,
             final String parentTypeName,
             final Optional<String> describedAs) {
-        super(elementType, collectionVariant, columnNameModel, sortProperty, propertyId, parentTypeName, describedAs);
+        super(elementType, collectionVariant, columnNameModel, sortable.orElse(null), propertyId, parentTypeName, describedAs);
     }
 
     @Override