HHH-18854 Allow changes to the id generator

Hibernate Reactive needs to replace or extends the original
id generators.

This changes make it possible to pass a function to the EntityMetamodel
that allows Hibernate Reactive to replace the original id generators

Author: DavideD

hibernate-core/src/main/java/org/hibernate/id/enhanced/TableStructure.java

@@ -111,6 +111,13 @@ public QualifiedName getPhysicalName() {
 		return physicalTableName;
 	}
 
+	/*
+	 * Used by Hibernate Reactive
+	 */
+	public Identifier getLogicalValueColumnNameIdentifier() {
+		return logicalValueColumnNameIdentifier;
+	}
+
 	@Override
 	public int getInitialValue() {
 		return initialValue;

hibernate-core/src/main/java/org/hibernate/persister/entity/AbstractEntityPersister.java

@@ -469,11 +469,38 @@ public abstract class AbstractEntityPersister
 	private List<UniqueKeyEntry> uniqueKeyEntries = null; //lazily initialized
 	private ConcurrentHashMap<String,SingleIdArrayLoadPlan> nonLazyPropertyLoadPlansByName;
 
+	/**
+	 * A factory for the creation of an EntityMetamodel.
+	 * <p>
+	 * Hibernate Reactive uses it to pass its own entity metamodel class
+	 * and adapt the identifier generators.
+	 */
+	public static class EntityMetamodelFactory {
+		public EntityMetamodel createEntityMetamodel(
+				PersistentClass persistentClass,
+				EntityPersister persister,
+				RuntimeModelCreationContext creationContext) {
+			return new EntityMetamodel( persistentClass, persister, creationContext );
+		}
+	}
+
 	public AbstractEntityPersister(
 			final PersistentClass persistentClass,
 			final EntityDataAccess cacheAccessStrategy,
 			final NaturalIdDataAccess naturalIdRegionAccessStrategy,
 			final RuntimeModelCreationContext creationContext) throws HibernateException {
+		this( persistentClass, cacheAccessStrategy, naturalIdRegionAccessStrategy, creationContext, new EntityMetamodelFactory() );
+	}
+
+	/*
+	 * Used by Hibernate Reactive
+	 */
+	public AbstractEntityPersister(
+			final PersistentClass persistentClass,
+			final EntityDataAccess cacheAccessStrategy,
+			final NaturalIdDataAccess naturalIdRegionAccessStrategy,
+			final RuntimeModelCreationContext creationContext,
+			final EntityMetamodelFactory entityMetamodelFactory) throws HibernateException {
 		this.jpaEntityName = persistentClass.getJpaEntityName();
 
 		//set it here, but don't call it, since it's still uninitialized!
@@ -500,7 +527,7 @@ public AbstractEntityPersister(
 			isLazyPropertiesCacheable = true;
 		}
 
-		entityMetamodel = new EntityMetamodel( persistentClass, this, creationContext );
+		entityMetamodel = entityMetamodelFactory.createEntityMetamodel( persistentClass, this, creationContext );
 
 		entityEntryFactory = entityMetamodel.isMutable()
 				? MutableEntityEntryFactory.INSTANCE

hibernate-core/src/main/java/org/hibernate/persister/entity/JoinedSubclassEntityPersister.java

@@ -160,8 +160,20 @@ public JoinedSubclassEntityPersister(
 			final EntityDataAccess cacheAccessStrategy,
 			final NaturalIdDataAccess naturalIdRegionAccessStrategy,
 			final RuntimeModelCreationContext creationContext) throws HibernateException {
+		this( persistentClass, cacheAccessStrategy, naturalIdRegionAccessStrategy, creationContext, new EntityMetamodelFactory());
+	}
+
+	/*
+	 * Used by Hibernate Reactive
+	 */
+	public JoinedSubclassEntityPersister(
+			final PersistentClass persistentClass,
+			final EntityDataAccess cacheAccessStrategy,
+			final NaturalIdDataAccess naturalIdRegionAccessStrategy,
+			final RuntimeModelCreationContext creationContext,
+			final EntityMetamodelFactory entityMetamodelFactory) throws HibernateException {
 
-		super( persistentClass, cacheAccessStrategy, naturalIdRegionAccessStrategy, creationContext );
+		super( persistentClass, cacheAccessStrategy, naturalIdRegionAccessStrategy, creationContext, entityMetamodelFactory );
 
 		final Dialect dialect = creationContext.getDialect();
 		final SqmFunctionRegistry functionRegistry = creationContext.getFunctionRegistry();

hibernate-core/src/main/java/org/hibernate/persister/entity/SingleTableEntityPersister.java

@@ -114,8 +114,20 @@ public SingleTableEntityPersister(
 			final EntityDataAccess cacheAccessStrategy,
 			final NaturalIdDataAccess naturalIdRegionAccessStrategy,
 			final RuntimeModelCreationContext creationContext) throws HibernateException {
+		this( persistentClass, cacheAccessStrategy, naturalIdRegionAccessStrategy, creationContext, new EntityMetamodelFactory() );
+	}
+
+	/*
+	 * Used by Hibernate Reactive
+	 */
+	public SingleTableEntityPersister(
+			final PersistentClass persistentClass,
+			final EntityDataAccess cacheAccessStrategy,
+			final NaturalIdDataAccess naturalIdRegionAccessStrategy,
+			final RuntimeModelCreationContext creationContext,
+			final EntityMetamodelFactory entityMetamodelFactory) throws HibernateException {
 
-		super( persistentClass, cacheAccessStrategy, naturalIdRegionAccessStrategy, creationContext );
+		super( persistentClass, cacheAccessStrategy, naturalIdRegionAccessStrategy, creationContext, entityMetamodelFactory );
 
 		final Dialect dialect = creationContext.getDialect();
 		final SqmFunctionRegistry functionRegistry = creationContext.getFunctionRegistry();

hibernate-core/src/main/java/org/hibernate/persister/entity/UnionSubclassEntityPersister.java

@@ -95,7 +95,19 @@ public UnionSubclassEntityPersister(
 			final EntityDataAccess cacheAccessStrategy,
 			final NaturalIdDataAccess naturalIdRegionAccessStrategy,
 			final RuntimeModelCreationContext creationContext) throws HibernateException {
-		super( persistentClass, cacheAccessStrategy, naturalIdRegionAccessStrategy, creationContext );
+		this( persistentClass, cacheAccessStrategy, naturalIdRegionAccessStrategy, creationContext, new EntityMetamodelFactory() );
+	}
+
+	/*
+	 * Used by Hibernate Reactive
+	 */
+	public UnionSubclassEntityPersister(
+			final PersistentClass persistentClass,
+			final EntityDataAccess cacheAccessStrategy,
+			final NaturalIdDataAccess naturalIdRegionAccessStrategy,
+			final RuntimeModelCreationContext creationContext,
+			final EntityMetamodelFactory entityMetamodelFactory) throws HibernateException {
+		super( persistentClass, cacheAccessStrategy, naturalIdRegionAccessStrategy, creationContext, entityMetamodelFactory );
 
 		validateGenerator();
 

hibernate-core/src/main/java/org/hibernate/tuple/entity/EntityMetamodel.java

@@ -13,6 +13,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.Function;
 
 import org.hibernate.HibernateException;
 import org.hibernate.MappingException;
@@ -149,6 +150,18 @@ public EntityMetamodel(
 			PersistentClass persistentClass,
 			EntityPersister persister,
 			RuntimeModelCreationContext creationContext) {
+		this( persistentClass, persister, creationContext,
+				rootName -> buildIdGenerator( rootName, persistentClass, creationContext ) );
+	}
+
+	/*
+	 * Used by Hibernate Reactive to adapt the id generators
+	 */
+	public EntityMetamodel(
+			PersistentClass persistentClass,
+			EntityPersister persister,
+			RuntimeModelCreationContext creationContext,
+			Function<String, Generator> generatorSupplier) {
 		this.sessionFactory = creationContext.getSessionFactory();
 
 		// Improves performance of EntityKey#equals by avoiding content check in String#equals
@@ -160,7 +173,7 @@ public EntityMetamodel(
 
 		subclassId = persistentClass.getSubclassId();
 
-		final Generator idgenerator = buildIdGenerator( persistentClass, creationContext );
+		final Generator idgenerator = generatorSupplier.apply( rootName );
 		identifierAttribute = PropertyFactory.buildIdentifierAttribute( persistentClass, idgenerator );
 
 		versioned = persistentClass.isVersioned();
@@ -483,7 +496,7 @@ private static boolean writePropertyValue(OnExecutionGenerator generator) {
 		return writePropertyValue;
 	}
 
-	private Generator buildIdGenerator(PersistentClass persistentClass, RuntimeModelCreationContext creationContext) {
+	private static Generator buildIdGenerator(String rootName, PersistentClass persistentClass, RuntimeModelCreationContext creationContext) {
 		final Generator existing = creationContext.getGenerators().get( rootName );
 		if ( existing != null ) {
 			return existing;