/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2013, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.loader.plan.build.internal;
import org.hibernate.HibernateException;
import org.hibernate.LockMode;
import org.hibernate.engine.FetchStrategy;
import org.hibernate.engine.FetchStyle;
import org.hibernate.engine.FetchTiming;
import org.hibernate.engine.spi.LoadQueryInfluencers;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.internal.CoreLogging;
import org.hibernate.loader.plan.build.spi.LoadPlanBuildingAssociationVisitationStrategy;
import org.hibernate.loader.plan.spi.CollectionReturn;
import org.hibernate.loader.plan.spi.EntityReturn;
import org.hibernate.loader.plan.spi.LoadPlan;
import org.hibernate.loader.plan.spi.Return;
import org.hibernate.persister.walking.spi.AssociationAttributeDefinition;
import org.jboss.logging.Logger;
/**
* {@link LoadPlanBuildingAssociationVisitationStrategy} implementation used for building LoadPlans based on metamodel-defined fetching. Built
* LoadPlans contain a single root return object, either an {@link EntityReturn} or a {@link CollectionReturn}.
*
* @author Steve Ebersole
*/
public class FetchStyleLoadPlanBuildingAssociationVisitationStrategy
extends AbstractLoadPlanBuildingAssociationVisitationStrategy {
private static final Logger log = CoreLogging.logger( FetchStyleLoadPlanBuildingAssociationVisitationStrategy.class );
private final LoadQueryInfluencers loadQueryInfluencers;
private final LockMode lockMode;
private Return rootReturn;
/**
* Constructs a FetchStyleLoadPlanBuildingAssociationVisitationStrategy.
*
* @param sessionFactory The session factory
* @param loadQueryInfluencers The options which can influence the SQL query needed to perform the load.
* @param lockMode The lock mode.
*/
public FetchStyleLoadPlanBuildingAssociationVisitationStrategy(
SessionFactoryImplementor sessionFactory,
LoadQueryInfluencers loadQueryInfluencers,
LockMode lockMode) {
super( sessionFactory );
this.loadQueryInfluencers = loadQueryInfluencers;
this.lockMode = lockMode;
}
@Override
protected boolean supportsRootEntityReturns() {
return true;
}
@Override
protected boolean supportsRootCollectionReturns() {
return true;
}
@Override
protected void addRootReturn(Return rootReturn) {
if ( this.rootReturn != null ) {
throw new HibernateException( "Root return already identified" );
}
this.rootReturn = rootReturn;
}
@Override
public LoadPlan buildLoadPlan() {
log.debug( "Building LoadPlan..." );
if ( EntityReturn.class.isInstance( rootReturn ) ) {
return new LoadPlanImpl( (EntityReturn) rootReturn, getQuerySpaces() );
}
else if ( CollectionReturn.class.isInstance( rootReturn ) ) {
return new LoadPlanImpl( (CollectionReturn) rootReturn, getQuerySpaces() );
}
else {
throw new IllegalStateException( "Unexpected root Return type : " + rootReturn );
}
}
@Override
protected FetchStrategy determineFetchStrategy(AssociationAttributeDefinition attributeDefinition) {
FetchStrategy fetchStrategy = attributeDefinition.determineFetchPlan( loadQueryInfluencers, currentPropertyPath );
if ( fetchStrategy.getTiming() == FetchTiming.IMMEDIATE && fetchStrategy.getStyle() == FetchStyle.JOIN ) {
// see if we need to alter the join fetch to another form for any reason
fetchStrategy = adjustJoinFetchIfNeeded( attributeDefinition, fetchStrategy );
}
return fetchStrategy;
}
/**
* If required by this strategy, returns a different {@link FetchStrategy} from what is specified
* for the given association attribute.
*
* @param attributeDefinition The association attribute definition.
* @param fetchStrategy The fetch strategy for <code>attributeDefinition</code>.
* @return the {@link FetchStrategy}, possibly adjusted by this strategy.
*/
protected FetchStrategy adjustJoinFetchIfNeeded(
AssociationAttributeDefinition attributeDefinition,
FetchStrategy fetchStrategy) {
if ( lockMode.greaterThan( LockMode.READ ) ) {
return new FetchStrategy( fetchStrategy.getTiming(), FetchStyle.SELECT );
}
final Integer maxFetchDepth = sessionFactory().getSettings().getMaximumFetchDepth();
if ( maxFetchDepth != null && currentDepth() > maxFetchDepth ) {
return new FetchStrategy( fetchStrategy.getTiming(), FetchStyle.SELECT );
}
if ( attributeDefinition.getType().isCollectionType() && isTooManyCollections() ) {
// todo : have this revert to batch or subselect fetching once "sql gen redesign" is in place
return new FetchStrategy( fetchStrategy.getTiming(), FetchStyle.SELECT );
}
return fetchStrategy;
}
@Override
protected boolean isTooManyCollections() {
return CollectionReturn.class.isInstance( rootReturn );
}
}