CAUSEWAY-3859: Java record refactoring (part 51)

core/metamodel/src/main/java/org/apache/causeway/core/metamodel/object/BookmarkedObjectHolder.java

@@ -0,0 +1,85 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied.  See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
+package org.apache.causeway.core.metamodel.object;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+import org.jspecify.annotations.NonNull;
+import org.jspecify.annotations.Nullable;
+
+import org.apache.causeway.applib.services.bookmark.Bookmark;
+import org.apache.causeway.core.metamodel.context.MetaModelContext;
+import org.apache.causeway.core.metamodel.objectmanager.ObjectManager;
+
+/**
+ * Transiently holds a detachable {@link ManagedObject},
+ * that is lazily created based on the given immutable {@link Bookmark}.
+ */
+public final class BookmarkedObjectHolder implements Serializable {
+    private static final long serialVersionUID = 1L;
+
+    private final Bookmark bookmark;
+    private transient ManagedObject managedObject;
+
+    public BookmarkedObjectHolder(final @NonNull Bookmark bookmark, final @Nullable ManagedObject managedObject) {
+        this.bookmark = bookmark;
+        this.managedObject = managedObject;
+    }
+
+    public Bookmark bookmark() {
+        return bookmark;
+    }
+
+    public ManagedObject managedObject() {
+        return managedObject!=null
+            ? managedObject
+            : (this.managedObject = objectManager().loadObjectElseFail(bookmark));
+    }
+
+    public void detach() {
+        this.managedObject = null;
+    }
+
+    // -- CONTRACT
+
+    @Override
+    public final int hashCode() {
+        return bookmark.hashCode();
+    }
+
+    @Override
+    public final boolean equals(final Object obj) {
+        return obj instanceof BookmarkedObjectHolder other
+            ? Objects.equals(this.bookmark, other.bookmark)
+            : false;
+    }
+
+    @Override
+    public String toString() {
+        return "ManagedObjectHolder[%s]".formatted(bookmark);
+    }
+
+    // -- HELPER
+
+    private ObjectManager objectManager() {
+        return MetaModelContext.instanceElseFail().getObjectManager();
+    }
+
+}

viewers/wicket/model/src/main/java/org/apache/causeway/viewer/wicket/model/models/UiObjectWkt.java

@@ -225,11 +225,11 @@ public UiAttributeWkt getPropertyModel(
         // (that is loading entities only if required),
         // this guard only triggers, once the first property model gets looked up;
         // in other words: this guard only works if every entity has at least a property
-        var ownerPojo = bookmarkedObjectModel.asManagedObject()
+        var ownerPojo = bookmarkedObjectModel.managedObject()
                 .getPojo();
         if(ownerPojo==null) {
             throw new ObjectNotFoundException(
-                    bookmarkedObjectModel.getBookmark().identifier());
+                    bookmarkedObjectModel.bookmark().identifier());
         }
 
         var propIdentifier = property.getFeatureIdentifier();

viewers/wicket/model/src/main/java/org/apache/causeway/viewer/wicket/model/models/coll/CollectionModelAbstract.java

@@ -70,7 +70,7 @@ protected CollectionModelAbstract(
 
     @Override
     protected DataTableInteractive load() {
-        var tableInteractive = tableMemento.getDataTableModel(bookmarkedObject.asManagedObject());
+        var tableInteractive = tableMemento.getDataTableModel(bookmarkedObject.managedObject());
         tableMemento.setupBindings(tableInteractive);
         return tableInteractive;
     }
@@ -98,7 +98,7 @@ public Identifier getIdentifier() {
 
     @Override
     public final ManagedObject getParentObject() {
-        return bookmarkedObject.asManagedObject();
+        return bookmarkedObject.managedObject();
     }
 
     /* XXX[CAUSEWAY-3798] do not override (as it was for the hidden table)

viewers/wicket/model/src/main/java/org/apache/causeway/viewer/wicket/model/models/interaction/BookmarkedObjectWkt.java

@@ -18,59 +18,51 @@
  */
 package org.apache.causeway.viewer.wicket.model.models.interaction;
 
+import org.apache.wicket.model.IModel;
+import org.jspecify.annotations.NonNull;
 import org.jspecify.annotations.Nullable;
 
 import org.apache.causeway.applib.services.bookmark.Bookmark;
 import org.apache.causeway.commons.internal.exceptions._Exceptions;
 import org.apache.causeway.core.metamodel.object.ManagedObject;
-import org.apache.causeway.viewer.wicket.model.models.ModelAbstract;
-
-import lombok.Getter;
-import org.jspecify.annotations.NonNull;
+import org.apache.causeway.core.metamodel.object.BookmarkedObjectHolder;
 
-public final class BookmarkedObjectWkt
-extends ModelAbstract<ManagedObject> {
-
-    private static final long serialVersionUID = 1L;
-    @Getter private final @NonNull Bookmark bookmark;
+public record BookmarkedObjectWkt(
+    @NonNull BookmarkedObjectHolder moHolder)
+implements IModel<ManagedObject> {
 
     /** overwrites any current cache entry, only safe when no other views/models reference the same ManagedObject */
     public static BookmarkedObjectWkt ofAdapter(
             final @NonNull ManagedObject domainObject) {
         var bookmark = domainObject.getBookmarkElseFail();
-        return new BookmarkedObjectWkt(bookmark, domainObject);
+        return new BookmarkedObjectWkt(new BookmarkedObjectHolder(bookmark, domainObject));
     }
 
     public static BookmarkedObjectWkt ofBookmark(final @Nullable Bookmark bookmark) {
-        return new BookmarkedObjectWkt(bookmark);
+        return new BookmarkedObjectWkt(new BookmarkedObjectHolder(bookmark, null));
     }
 
-    private BookmarkedObjectWkt(final @NonNull Bookmark bookmark) {
-        super();
-        this.bookmark = bookmark;
+    public Bookmark bookmark() {
+        return moHolder.bookmark();
     }
 
-    private BookmarkedObjectWkt(
-            final @NonNull Bookmark bookmark,
-            final @Nullable ManagedObject domainObject) {
-        super(domainObject);
-        this.bookmark = bookmark;
+    public ManagedObject managedObject() {
+        return moHolder.managedObject();
     }
 
-    public final ManagedObject asManagedObject() {
-        var entityOrViewmodel = super.getObject();
-        return entityOrViewmodel;
+    @Override
+    public ManagedObject getObject() {
+        return managedObject();
     }
 
     @Override
-    public final void setObject(final ManagedObject object) {
-        throw _Exceptions.unsupportedOperation("ManagedObjectWkt is immuatable");
+    public void setObject(final ManagedObject object) {
+        throw _Exceptions.unsupportedOperation("BookmarkedObjectWkt is immuatable");
     }
 
     @Override
-    protected final ManagedObject load() {
-        var adapter = getMetaModelContext().getObjectManager().loadObjectElseFail(bookmark);
-        return adapter;
+    public void detach() {
+        moHolder.detach();
     }
 
 }

viewers/wicket/model/src/main/java/org/apache/causeway/viewer/wicket/model/models/interaction/HasBookmarkedOwnerAbstract.java

@@ -39,12 +39,12 @@ public abstract class HasBookmarkedOwnerAbstract<T>
 
     @Override
     public final Bookmark getOwnerBookmark() {
-        return bookmarkedObject.getBookmark();
+        return bookmarkedObject.bookmark();
     }
 
     @Override
     public final ManagedObject getBookmarkedOwner() {
-        return bookmarkedObject.asManagedObject();
+        return bookmarkedObject.managedObject();
     }
 
     public final BookmarkedObjectWkt bookmarkedObjectModel() {