Introduce `VirtualIdEmbeddable` and `IdClassEmbeddable`

This 3rd commit cleans up some code

Still need to
  - integrate EmbeddableInstantiator work
  - integrate embedded forms.  `VirtualIdEmbeddable` does not really need it as it can use the id-mapping itself as the embedded form.  But `IdClassEmbedded` should really be integrated
  - integrate `VirtualKeyEmbeddable` and `VirtualKeyEmbedded` for use as inverse composite fks
  - share `#finishInit` handling for `EmbeddableMappingType`, `VirtualIdEmbeddable` and `IdClassEmbeddable`

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/EmbeddableMappingType.java

@@ -20,12 +20,6 @@ import org.hibernate.sql.ast.tree.from.TableGroupProducer;
  * @see EmbeddableValuedModelPart
  */
 public interface EmbeddableMappingType extends ManagedMappingType, SelectableMappings {
-	EmbeddableMappingType createInverseMappingType(
-			EmbeddedAttributeMapping valueMapping,
-			TableGroupProducer declaringTableGroupProducer,
-			SelectableMappings selectableMappings,
-			MappingModelCreationProcess creationProcess);
-
 	EmbeddableValuedModelPart getEmbeddedValueMapping();
 
 	EmbeddableRepresentationStrategy getRepresentationStrategy();
@@ -36,6 +30,12 @@ public interface EmbeddableMappingType extends ManagedMappingType, SelectableMap
 
 	boolean isCreateEmptyCompositesEnabled();
 
+	EmbeddableMappingType createInverseMappingType(
+			EmbeddedAttributeMapping valueMapping,
+			TableGroupProducer declaringTableGroupProducer,
+			SelectableMappings selectableMappings,
+			MappingModelCreationProcess creationProcess);
+
 	@Override
 	default int forEachSelectable(SelectableConsumer consumer) {
 		return ManagedMappingType.super.forEachSelectable( consumer );

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/EmbeddableValuedModelPart.java

@@ -21,13 +21,11 @@ import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.FetchableContainer;
 
 /**
- * An embedded (embeddable-valued) model part.
+ * Describes the mapping of an embeddable (composite).
  *
  * @see jakarta.persistence.Embedded
  * @see jakarta.persistence.EmbeddedId
  * @see jakarta.persistence.Embeddable
- *
- * @author Steve Ebersole
  */
 public interface EmbeddableValuedModelPart extends ModelPart, Fetchable, FetchableContainer, TableGroupJoinProducer {
 	EmbeddableMappingType getEmbeddableTypeDescriptor();

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/NonAggregatedIdentifierMapping.java

@@ -0,0 +1,72 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.metamodel.mapping;
+
+import org.hibernate.engine.spi.SharedSessionContractImplementor;
+import org.hibernate.mapping.IndexedConsumer;
+import org.hibernate.metamodel.mapping.internal.IdClassEmbeddable;
+import org.hibernate.metamodel.mapping.internal.VirtualIdEmbeddable;
+import org.hibernate.sql.results.graph.FetchOptions;
+import org.hibernate.sql.results.graph.embeddable.EmbeddableValuedFetchable;
+
+/**
+ * A "non-aggregated" composite identifier, which means that the entity itself
+ * does not define a singular representation of its identifier like an
+ * {@link jakarta.persistence.EmbeddedId} does.
+ *
+ * An IdClass can be used to provide a simple, singular representation of the
+ * identifier for easier reference in API calls.  JPA requires using an IdClass
+ * when mapping such identifiers. Hibernate supports mapping such identifiers
+ * with or without the IdClass; without, the entity itself is used as the
+ * identifier.
+ *
+ * @see jakarta.persistence.IdClass
+ * @see jakarta.persistence.MapsId
+ */
+public interface NonAggregatedIdentifierMapping extends CompositeIdentifierMapping, EmbeddableValuedFetchable, FetchOptions {
+	/**
+	 * The virtual-id representation of this id mapping
+	 */
+	VirtualIdEmbeddable getVirtualIdEmbeddable();
+
+	/**
+	 * The id-class representation of this id mapping
+	 */
+	IdClassEmbeddable getIdClassEmbeddable();
+
+	/**
+	 * The id-class, if there is one, otherwise the virtual-id.
+	 */
+	IdentifierValueMapper getIdentifierValueMapper();
+
+	/**
+	 * Think of an AttributeConverter for id values to account for representation
+	 * difference between virtual and id-class mappings
+	 */
+	interface IdentifierValueMapper extends EmbeddableMappingType {
+		EmbeddableValuedModelPart getEmbeddedPart();
+
+		/**
+		 * Extract the identifier out of the given entity, returning the mapper's
+		 * representation
+		 */
+		Object getIdentifier(Object entity, SharedSessionContractImplementor session);
+
+		/**
+		 * Extract the identifier out of the given entity, returning the mapper's
+		 * representation
+		 */
+		void setIdentifier(Object entity, Object id, SharedSessionContractImplementor session);
+
+		/**
+		 * Convenience method to iterate the attributes for this mapper's representation
+		 */
+		default void forEachAttribute(IndexedConsumer<SingularAttributeMapping> consumer) {
+			getEmbeddedPart().getEmbeddableTypeDescriptor().forEachAttributeMapping( (IndexedConsumer) consumer );
+		}
+	}
+}

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/EmbeddableMappingTypeImpl.java

@@ -155,7 +155,6 @@ public class EmbeddableMappingTypeImpl implements EmbeddableMappingType, Selecta
 	private SelectableMappings selectableMappings;
 
 	private final EmbeddableValuedModelPart valueMapping;
-	private NavigableRole embeddedRole;
 
 	private final boolean createEmptyCompositesEnabled;
 
@@ -354,10 +353,10 @@ public class EmbeddableMappingTypeImpl implements EmbeddableMappingType, Selecta
 				final boolean updateable = bootPropertyDescriptor.isUpdateable();
 				final boolean includeInOptimisticLocking = bootPropertyDescriptor.isOptimisticLocked();
 				final CascadeStyle cascadeStyle = compositeType.getCascadeStyle( attributeIndex );
-				final MutabilityPlan mutabilityPlan;
+				final MutabilityPlan<?> mutabilityPlan;
 
 				if ( updateable ) {
-					mutabilityPlan = new MutabilityPlan() {
+					mutabilityPlan = new MutabilityPlan<Object>() {
 						@Override
 						public boolean isMutable() {
 							return true;
@@ -394,7 +393,7 @@ public class EmbeddableMappingTypeImpl implements EmbeddableMappingType, Selecta
 					}
 
 					@Override
-					public MutabilityPlan getMutabilityPlan() {
+					public MutabilityPlan<?> getMutabilityPlan() {
 						return mutabilityPlan;
 					}
 
@@ -523,7 +522,7 @@ public class EmbeddableMappingTypeImpl implements EmbeddableMappingType, Selecta
 
 		// We need the attribute mapping types to finish initialization first before we can build the column mappings
 		creationProcess.registerInitializationCallback(
-				"EmbeddableMappingType(" + embeddedRole + ")#initColumnMappings",
+				"EmbeddableMappingType(" + getEmbeddedValueMapping().getNavigableRole().getFullPath() + ")#initColumnMappings",
 				this::initColumnMappings
 		);
 		return true;
@@ -560,7 +559,7 @@ public class EmbeddableMappingTypeImpl implements EmbeddableMappingType, Selecta
 	}
 
 	@Override
-	public JavaType getMappedJavaTypeDescriptor() {
+	public JavaType<?> getMappedJavaTypeDescriptor() {
 		return embeddableJtd;
 	}
 
@@ -625,10 +624,8 @@ public class EmbeddableMappingTypeImpl implements EmbeddableMappingType, Selecta
 	}
 
 	@Override
-	public void visitFetchables(
+	public void visitFetchables(Consumer<Fetchable> fetchableConsumer, EntityMappingType treatTargetType) {
-			Consumer<Fetchable> fetchableConsumer,
+		visitAttributeMappings( fetchableConsumer );
-			EntityMappingType treatTargetType) {
-		visitAttributeMappings( attributeMapping -> fetchableConsumer.accept( attributeMapping ) );
 	}
 
 	@Override
@@ -780,10 +777,8 @@ public class EmbeddableMappingTypeImpl implements EmbeddableMappingType, Selecta
 	}
 
 	@Override
-	public void visitSubParts(
+	public void visitSubParts(Consumer<ModelPart> consumer, EntityMappingType treatTargetType) {
-			Consumer<ModelPart> consumer,
+		visitAttributeMappings( consumer );
-			EntityMappingType treatTargetType) {
-		visitAttributeMappings( consumer::accept );
 	}
 
 	public Object[] getPropertyValues(Object compositeInstance) {

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/IdClassEmbeddable.java

@@ -35,14 +35,14 @@ import org.hibernate.mapping.RootClass;
 import org.hibernate.mapping.Selectable;
 import org.hibernate.mapping.Table;
 import org.hibernate.metamodel.mapping.AttributeMapping;
-import org.hibernate.metamodel.mapping.internal.EmbeddableMappingTypeImpl;
+import org.hibernate.metamodel.mapping.EmbeddableMappingType;
 import org.hibernate.metamodel.mapping.EmbeddableValuedModelPart;
 import org.hibernate.metamodel.mapping.EntityIdentifierMapping;
 import org.hibernate.metamodel.mapping.EntityMappingType;
-import org.hibernate.metamodel.mapping.EmbeddableMappingType;
 import org.hibernate.metamodel.mapping.JdbcMapping;
 import org.hibernate.metamodel.mapping.MappingModelCreationLogger;
 import org.hibernate.metamodel.mapping.ModelPart;
+import org.hibernate.metamodel.mapping.NonAggregatedIdentifierMapping;
 import org.hibernate.metamodel.mapping.PluralAttributeMapping;
 import org.hibernate.metamodel.mapping.SelectableConsumer;
 import org.hibernate.metamodel.mapping.SelectableMapping;
@@ -50,7 +50,7 @@ import org.hibernate.metamodel.mapping.SelectableMappings;
 import org.hibernate.metamodel.mapping.SingularAttributeMapping;
 import org.hibernate.metamodel.mapping.StateArrayContributorMetadata;
 import org.hibernate.metamodel.mapping.StateArrayContributorMetadataAccess;
-import org.hibernate.metamodel.mapping.internal.NonAggregatedIdentifierMapping.IdentifierValueMapper;
+import org.hibernate.metamodel.mapping.NonAggregatedIdentifierMapping.IdentifierValueMapper;
 import org.hibernate.metamodel.model.domain.NavigableRole;
 import org.hibernate.metamodel.spi.EmbeddableRepresentationStrategy;
 import org.hibernate.persister.entity.EntityPersister;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/MappingModelCreationHelper.java

@@ -125,10 +125,6 @@ public class MappingModelCreationHelper {
 		final PropertyAccess propertyAccess = entityPersister.getRepresentationStrategy()
 				.resolvePropertyAccess( bootEntityDescriptor.getIdentifierProperty() );
 
-		final StateArrayContributorMetadataAccess attributeMetadataAccess = getStateArrayContributorMetadataAccess(
-				propertyAccess
-		);
-
 		final EmbeddableMappingTypeImpl embeddableMappingType = EmbeddableMappingTypeImpl.from(
 				(Component) bootProperty.getValue(),
 				cidType,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/NonAggregatedIdentifierMapping.java

@@ -1,41 +0,0 @@
-/*
- * Hibernate, Relational Persistence for Idiomatic Java
- *
- * License: GNU Lesser General Public License (LGPL), version 2.1 or later
- * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
- */
-package org.hibernate.metamodel.mapping.internal;
-
-import org.hibernate.engine.spi.SharedSessionContractImplementor;
-import org.hibernate.mapping.IndexedConsumer;
-import org.hibernate.metamodel.mapping.CompositeIdentifierMapping;
-import org.hibernate.metamodel.mapping.EmbeddableValuedModelPart;
-import org.hibernate.metamodel.mapping.EmbeddableMappingType;
-import org.hibernate.metamodel.mapping.SingularAttributeMapping;
-import org.hibernate.sql.results.graph.FetchOptions;
-import org.hibernate.sql.results.graph.embeddable.EmbeddableValuedFetchable;
-
-/**
- * @author Steve Ebersole
- */
-public interface NonAggregatedIdentifierMapping extends CompositeIdentifierMapping, EmbeddableValuedFetchable, FetchOptions {
-	IdClassEmbeddable getIdClassEmbeddable();
-	VirtualIdEmbeddable getVirtualIdEmbeddable();
-
-	IdentifierValueMapper getIdentifierValueMapper();
-
-	/**
-	 * Think of an AttributeConverter for id values.  Handles representation
-	 * difference between virtual and id-class mappings
-	 */
-	interface IdentifierValueMapper extends EmbeddableMappingType {
-		EmbeddableValuedModelPart getEmbeddedPart();
-
-		Object getIdentifier(Object entity, SharedSessionContractImplementor session);
-		void setIdentifier(Object entity, Object id, SharedSessionContractImplementor session);
-
-		default void forEachAttribute(IndexedConsumer<SingularAttributeMapping> consumer) {
-			getEmbeddedPart().getEmbeddableTypeDescriptor().forEachAttributeMapping( (IndexedConsumer) consumer );
-		}
-	}
-}

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/NonAggregatedIdentifierMappingImpl.java

@@ -23,6 +23,7 @@ import org.hibernate.metamodel.mapping.ForeignKeyDescriptor;
 import org.hibernate.metamodel.mapping.EmbeddableMappingType;
 import org.hibernate.metamodel.mapping.JdbcMapping;
 import org.hibernate.metamodel.mapping.ModelPart;
+import org.hibernate.metamodel.mapping.NonAggregatedIdentifierMapping;
 import org.hibernate.metamodel.mapping.SelectableMappings;
 import org.hibernate.persister.entity.EntityPersister;
 import org.hibernate.query.NavigablePath;

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/VirtualIdEmbeddable.java

@@ -37,6 +37,7 @@ import org.hibernate.metamodel.mapping.EntityMappingType;
 import org.hibernate.metamodel.mapping.JdbcMapping;
 import org.hibernate.metamodel.mapping.MappingModelCreationLogger;
 import org.hibernate.metamodel.mapping.ModelPart;
+import org.hibernate.metamodel.mapping.NonAggregatedIdentifierMapping;
 import org.hibernate.metamodel.mapping.NonTransientException;
 import org.hibernate.metamodel.mapping.PluralAttributeMapping;
 import org.hibernate.metamodel.mapping.SelectableConsumer;
@@ -67,7 +68,7 @@ import org.hibernate.type.spi.CompositeTypeImplementor;
 import org.hibernate.type.spi.TypeConfiguration;
 
 import static org.hibernate.internal.util.collections.CollectionHelper.arrayList;
-import static org.hibernate.metamodel.mapping.internal.NonAggregatedIdentifierMapping.IdentifierValueMapper;
+import static org.hibernate.metamodel.mapping.NonAggregatedIdentifierMapping.IdentifierValueMapper;
 
 /**
  * Embeddable describing the virtual-id aspect of a non-aggregated composite id
@@ -104,7 +105,7 @@ public class VirtualIdEmbeddable implements IdentifierValueMapper {
 		final CompositeType compositeType = (CompositeType) virtualIdSource.getType();
 		this.attributeMappings = arrayList( (compositeType).getPropertyNames().length );
 
-		// todo (6.0) : can this be a separate VirtualIdEmbedded?
+		// todo (6.0) : can/should this be a separate VirtualIdEmbedded?
 		( (CompositeTypeImplementor) compositeType ).injectMappingModelPart( idMapping, creationProcess );
 
 		creationProcess.registerInitializationCallback(
@@ -146,56 +147,6 @@ public class VirtualIdEmbeddable implements IdentifierValueMapper {
 		);
 	}
 
-	public VirtualIdEmbeddable(
-			NonAggregatedIdentifierMapping idMapping,
-			EntityMappingType identifiedEntityMapping,
-			Component bootDescriptor,
-			CompositeType compositeType,
-			String rootTableExpression,
-			String[] rootTableKeyColumnNames,
-			MappingModelCreationProcess creationProcess) {
-		this.sessionFactory = creationProcess.getCreationContext().getSessionFactory();
-
-		this.navigableRole = idMapping.getNavigableRole();
-		this.idMapping = idMapping;
-		this.javaType = identifiedEntityMapping.getJavaTypeDescriptor();
-		this.attributeMappings = arrayList( compositeType.getPropertyNames().length );
-
-		this.representationStrategy = new VirtualIdRepresentationStrategy( identifiedEntityMapping );
-
-		( (CompositeTypeImplementor) compositeType ).injectMappingModelPart( getEmbeddedValueMapping(), creationProcess );
-
-		creationProcess.registerInitializationCallback(
-				"EmbeddableMappingType(" + navigableRole.getFullPath() + ")#finishInitialization",
-				() -> {
-					try {
-						final boolean finished = finishInitialization(
-								bootDescriptor,
-								compositeType,
-								rootTableExpression,
-								rootTableKeyColumnNames,
-								creationProcess
-						);
-
-						if ( finished ) {
-							return finished;
-						}
-					}
-					catch (Exception e) {
-						if ( e instanceof NonTransientException ) {
-							throw e;
-						}
-					}
-
-					MappingModelCreationLogger.LOGGER.debugf(
-							"EmbeddableMappingType(%s) finalization was not able to complete successfully",
-							navigableRole
-					);
-					return false;
-				}
-		);
-	}
-
 	// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 	// IdentifierValueMapper