HHH-18815 introduce Generator.generatedBeforeExecution()

so that GeneratedGeneration does not need to implement BeforeExecutionGenerator

Signed-off-by: Gavin King <gavin@hibernate.org>

hibernate-core/src/main/java/org/hibernate/event/internal/AbstractSaveEventListener.java

@@ -103,6 +103,7 @@ public abstract class AbstractSaveEventListener<C> implements CallbackRegistryCo
 		final EntityPersister persister = source.getEntityPersister( entityName, entity );
 		final Generator generator = persister.getGenerator();
 		final boolean generatedOnExecution = generator.generatedOnExecution( entity, source );
+		final boolean generatedBeforeExecution = generator.generatedBeforeExecution( entity, source );
 		final Object generatedId;
 		if ( generatedOnExecution ) {
 			// the id gets generated by the database
@@ -114,7 +115,7 @@ public abstract class AbstractSaveEventListener<C> implements CallbackRegistryCo
 			// the @PrePersist callback to happen first
 			generatedId = null;
 		}
-		else {
+		else if ( generatedBeforeExecution ) {
 			// go ahead and generate id, and then set it to
 			// the entity instance, so it will be available
 			// to the entity in the @PrePersist callback
@@ -124,6 +125,11 @@ public abstract class AbstractSaveEventListener<C> implements CallbackRegistryCo
 			}
 			persister.setIdentifier( entity, generatedId, source );
 		}
+		else {
+			// the generator is refusing to generate anything
+			// so use the identifier currently assigned
+			generatedId = persister.getIdentifier( entity, source );
+		}
 		final boolean delayIdentityInserts =
 				!source.isTransactionInProgress()
 						&& !requiresImmediateIdAccess

hibernate-core/src/main/java/org/hibernate/generator/Assigned.java

@@ -5,6 +5,7 @@
 package org.hibernate.generator;
 
 import org.hibernate.Internal;
+import org.hibernate.engine.spi.SharedSessionContractImplementor;
 
 import java.util.EnumSet;
 
@@ -29,6 +30,16 @@ public class Assigned implements Generator {
 		return false;
 	}
 
+	@Override
+	public boolean generatedOnExecution(Object entity, SharedSessionContractImplementor session) {
+		return false;
+	}
+
+	@Override
+	public boolean generatedBeforeExecution(Object entity, SharedSessionContractImplementor session) {
+		return false;
+	}
+
 	@Override
 	public boolean allowAssignedIdentifiers() {
 		return true;

hibernate-core/src/main/java/org/hibernate/generator/Generator.java

@@ -32,9 +32,10 @@ import static org.hibernate.generator.EventType.UPDATE;
  *	   SQL {@code select}, though in certain cases this additional round trip may be avoided.
  *	   An important example is id generation using an identity column.
  * </ul>
- * A Generator may implement both interfaces and determine the timing of ID generation at runtime.
+ * A {@code Generator} may implement both interfaces and determine the timing of identifier
- * Furthermore, this condition can be based on the state of the owner entity, see
+ * generation at runtime. Furthermore, this condition can be based on the state of the owner entity,
- * {@link #generatedOnExecution(Object, SharedSessionContractImplementor) generatedOnExecution}.
+ * see {@link #generatedOnExecution(Object, SharedSessionContractImplementor) generatedOnExecution} and
+ * {@link #generatedBeforeExecution(Object, SharedSessionContractImplementor) generatedBeforeExecution}.
  * <p>
  * Generically, a generator may be integrated with the program using the meta-annotation
  * {@link org.hibernate.annotations.ValueGenerationType}, which associates the generator with
@@ -95,20 +96,16 @@ public interface Generator extends Serializable {
 	boolean generatedOnExecution();
 
 	/**
-	 * Determines if the property value is generated when a row is written to the database,
+	 * Determines if the property value is generated when a row is written to the database.
-	 * or in Java code that executes before the row is written.
 	 * <p>
-	 * Defaults to {@link #generatedOnExecution()}, but can be overloaded allowing conditional
+	 * Defaults to {@link #generatedOnExecution()}, but may be overridden to allow conditional
-	 * value generation timing (on/before execution) based on the current state of the owner entity.
+	 * on-execution value generation based on the current state of the owner entity.
-	 * Note that a generator <b>must</b> implement both {@link BeforeExecutionGenerator} and
-	 * {@link OnExecutionGenerator} to achieve this behavior.
 	 *
 	 * @param entity The instance of the entity owning the attribute for which we are generating a value.
 	 * @param session The session from which the request originates.
 	 *
 	 * @return {@code true} if the value is generated by the database as a side effect of
-	 *         the execution of an {@code insert} or {@code update} statement, or false if
+	 *         the execution of an {@code insert} or {@code update} statement.
-	 *         it is generated in Java code before the statement is executed via JDBC.
 	 *
 	 * @see #generatedOnExecution()
 	 * @see BeforeExecutionGenerator
@@ -120,6 +117,30 @@ public interface Generator extends Serializable {
 		return generatedOnExecution();
 	}
 
+	/**
+	 * Determines if the property value is generated before in Java code that executes before
+	 * the row is written.
+	 * <p>
+	 * Defaults to {@link #generatedOnExecution() !generatedOnExecution()}, but may be overridden
+	 * to allow conditional before-execution value generation based on the current state of the
+	 * owner entity.
+	 *
+	 * @param entity The instance of the entity owning the attribute for which we are generating a value.
+	 * @param session The session from which the request originates.
+	 *
+	 * @return {@code true} if the value is generated in Java code before the statement is
+	 *         executed via JDBC.
+	 *
+	 * @see #generatedOnExecution()
+	 * @see BeforeExecutionGenerator
+	 * @see OnExecutionGenerator
+	 *
+	 * @since 7.0
+	 */
+	default boolean generatedBeforeExecution(Object entity, SharedSessionContractImplementor session) {
+		return !generatedOnExecution();
+	}
+
 	/**
 	 * The {@linkplain EventType event types} for which this generator should be called
 	 * to produce a new value.

hibernate-core/src/main/java/org/hibernate/generator/internal/GeneratedGeneration.java

@@ -8,7 +8,6 @@ import org.hibernate.AnnotationException;
 import org.hibernate.annotations.Generated;
 import org.hibernate.dialect.Dialect;
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
-import org.hibernate.generator.BeforeExecutionGenerator;
 import org.hibernate.generator.EventType;
 import org.hibernate.generator.OnExecutionGenerator;
 import org.hibernate.persister.entity.EntityPersister;
@@ -27,7 +26,7 @@ import static org.hibernate.internal.util.StringHelper.isEmpty;
  * @author Steve Ebersole
  * @author Gunnar Morling
  */
-public class GeneratedGeneration implements OnExecutionGenerator, BeforeExecutionGenerator {
+public class GeneratedGeneration implements OnExecutionGenerator {
 
 	private final EnumSet<EventType> eventTypes;
 	private final boolean writable;
@@ -72,11 +71,6 @@ public class GeneratedGeneration implements OnExecutionGenerator, BeforeExecutio
 		return writable;
 	}
 
-	@Override
-	public boolean generatedOnExecution() {
-		return true;
-	}
-
 	@Override
 	public boolean generatedOnExecution(Object entity, SharedSessionContractImplementor session) {
 		if ( writable ) {
@@ -90,13 +84,6 @@ public class GeneratedGeneration implements OnExecutionGenerator, BeforeExecutio
 		}
 	}
 
-	@Override
-	public Object generate(SharedSessionContractImplementor session, Object owner, Object currentValue, EventType eventType) {
-		final EntityPersister entityPersister = session.getEntityPersister( null, owner );
-		assert entityPersister.getGenerator() == this;
-		return entityPersister.getIdentifier( owner, session );
-	}
-
 	@Override
 	public boolean allowAssignedIdentifiers() {
 		return writable;

hibernate-core/src/main/java/org/hibernate/internal/StatelessSessionImpl.java

@@ -146,32 +146,47 @@ public class StatelessSessionImpl extends AbstractSharedSessionContract implemen
 			}
 		}
 		final Generator generator = persister.getGenerator();
-		if ( !generator.generatedOnExecution( entity, this ) ) {
+		if ( generator.generatedBeforeExecution( entity, this ) ) {
-			if ( generator.generatesOnInsert() ) {
+			if ( !generator.generatesOnInsert() ) {
+				throw new IdentifierGenerationException( "Identifier generator must generate on insert" );
+			}
 			id = ( (BeforeExecutionGenerator) generator).generate( this, entity, null, INSERT );
+			if ( firePreInsert(entity, id, state, persister) ) {
+				return id;
 			}
 			else {
+				getInterceptor().onInsert( entity, id, state, persister.getPropertyNames(), persister.getPropertyTypes() );
+				persister.getInsertCoordinator().insert( entity, id, state, this );
+				persister.setIdentifier( entity, id, this );
+			}
+		}
+		else if ( generator.generatedOnExecution( entity, this ) ) {
+			if ( !generator.generatesOnInsert() ) {
+				throw new IdentifierGenerationException( "Identifier generator must generate on insert" );
+			}
+			if ( firePreInsert(entity, null, state, persister) ) {
+				return null;
+			}
+			else {
+				getInterceptor().onInsert( entity, null, state, persister.getPropertyNames(), persister.getPropertyTypes() );
+				final GeneratedValues generatedValues = persister.getInsertCoordinator().insert( entity, state, this );
+				id = castNonNull( generatedValues ).getGeneratedValue( persister.getIdentifierMapping() );
+				persister.setIdentifier( entity, id, this );
+			}
+		}
+		else { // assigned identifier
 			id = persister.getIdentifier( entity, this );
 			if ( id == null ) {
 				throw new IdentifierGenerationException( "Identifier of entity '" + persister.getEntityName() + "' must be manually assigned before calling 'insert()'" );
 			}
-			}
 			if ( firePreInsert(entity, id, state, persister) ) {
 				return id;
 			}
+			else {
 				getInterceptor().onInsert( entity, id, state, persister.getPropertyNames(), persister.getPropertyTypes() );
 				persister.getInsertCoordinator().insert( entity, id, state, this );
 			}
-		else {
-			if ( firePreInsert(entity, null, state, persister) ) {
-				return null;
 		}
-			getInterceptor()
-					.onInsert( entity, null, state, persister.getPropertyNames(), persister.getPropertyTypes() );
-			final GeneratedValues generatedValues = persister.getInsertCoordinator().insert( entity, state, this );
-			id = castNonNull( generatedValues ).getGeneratedValue( persister.getIdentifierMapping() );
-		}
-		persister.setIdentifier( entity, id, this );
 		forEachOwnedCollection( entity, id, persister,
 				(descriptor, collection) -> {
 					descriptor.recreate( collection, id, this);

hibernate-core/src/main/java/org/hibernate/mapping/Component.java

@@ -776,7 +776,7 @@ public class Component extends SimpleValue implements MetaAttributable, Sortable
 
 		@Override
 		public Object execute(SharedSessionContractImplementor session, Object incomingObject) {
-			if ( !generator.generatedOnExecution( incomingObject, session ) ) {
+			if ( generator.generatedBeforeExecution( incomingObject, session ) ) {
 				return generator.generate( session, incomingObject, null, INSERT );
 			}
 			else {

hibernate-core/src/main/java/org/hibernate/persister/entity/mutation/InsertCoordinatorStandard.java

@@ -140,7 +140,7 @@ public class InsertCoordinatorStandard extends AbstractMutationCoordinator imple
 				final Generator generator = generators[i];
 				if ( generator != null
 						&& generator.generatesOnInsert()
-						&& !generator.generatedOnExecution( entity, session ) ) {
+						&& generator.generatedBeforeExecution( entity, session ) ) {
 					values[i] = ( (BeforeExecutionGenerator) generator ).generate( session, entity, values[i], INSERT );
 					persister.setPropertyValue( entity, i, values[i] );
 					foundStateDependentGenerator = foundStateDependentGenerator || generator.generatedOnExecution();
@@ -407,7 +407,7 @@ public class InsertCoordinatorStandard extends AbstractMutationCoordinator imple
 				else {
 					final Generator generator = attributeMapping.getGenerator();
 					if ( isValueGenerated( generator ) ) {
-						if ( session != null && !generator.generatedOnExecution( object, session ) ) {
+						if ( session != null && generator.generatedBeforeExecution( object, session ) ) {
 							attributeInclusions[attributeIndex] = true;
 							attributeMapping.forEachInsertable( insertGroupBuilder );
 						}

hibernate-core/src/main/java/org/hibernate/persister/entity/mutation/UpdateCoordinatorStandard.java

@@ -540,7 +540,7 @@ public class UpdateCoordinatorStandard extends AbstractMutationCoordinator imple
 				final Generator generator = generators[i];
 				if ( generator != null
 						&& generator.generatesOnUpdate()
-						&& !generator.generatedOnExecution( object, session ) ) {
+						&& generator.generatedBeforeExecution( object, session ) ) {
 					newValues[i] = ( (BeforeExecutionGenerator) generator ).generate( session, object, newValues[i], UPDATE );
 					entityPersister().setPropertyValue( object, i, newValues[i] );
 					fieldsPreUpdateNeeded[count++] = i;
@@ -667,7 +667,8 @@ public class UpdateCoordinatorStandard extends AbstractMutationCoordinator imple
 
 		final Generator generator = attributeMapping.getGenerator();
 		final boolean generated = isValueGenerated( generator );
-		final boolean needsDynamicUpdate = generated && session != null && !generator.generatedOnExecution( entity, session );
+		final boolean needsDynamicUpdate =
+				generated && session != null && generator.generatedBeforeExecution( entity, session );
 		final boolean generatedInSql = generated && isValueGenerationInSql( generator, dialect );
 		if ( generatedInSql && !needsDynamicUpdate && !( (OnExecutionGenerator) generator ).writePropertyValue() ) {
 			analysis.registerValueGeneratedInSqlNoWrite();

hibernate-core/src/test/java/org/hibernate/orm/test/idgen/userdefined/MixedTimingGeneratorsTest.java

@@ -306,8 +306,13 @@ public class MixedTimingGeneratorsTest {
 		}
 
 		@Override
-		public boolean generatedOnExecution(Object owner, SharedSessionContractImplementor session) {
+		public boolean generatedOnExecution(Object entity, SharedSessionContractImplementor session) {
-			return !( (RandomEntity) owner ).getName().contains( "random" );
+			return !generatedBeforeExecution( entity, session );
+		}
+
+		@Override
+		public boolean generatedBeforeExecution(Object entity, SharedSessionContractImplementor session) {
+			return ( (RandomEntity) entity ).getName().contains( "random" );
 		}
 	}
 
@@ -333,8 +338,13 @@ public class MixedTimingGeneratorsTest {
 		}
 
 		@Override
-		public boolean generatedOnExecution(Object owner, SharedSessionContractImplementor session) {
+		public boolean generatedOnExecution(Object entity, SharedSessionContractImplementor session) {
-			return !( (StringGeneratedEntity) owner ).getName().contains( "generated" );
+			return !generatedBeforeExecution( entity, session );
+		}
+
+		@Override
+		public boolean generatedBeforeExecution(Object entity, SharedSessionContractImplementor session) {
+			return ( (StringGeneratedEntity) entity ).getName().contains( "generated" );
 		}
 
 		@Override