/*
* 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.spi.visit;
import java.util.List;
import org.hibernate.loader.plan.spi.CollectionFetch;
import org.hibernate.loader.plan.spi.CollectionReturn;
import org.hibernate.loader.plan.spi.CompositeFetch;
import org.hibernate.loader.plan.spi.EntityFetch;
import org.hibernate.loader.plan.spi.EntityReturn;
import org.hibernate.loader.plan.spi.Fetch;
import org.hibernate.loader.plan.spi.FetchOwner;
import org.hibernate.loader.plan.spi.Return;
import org.hibernate.loader.plan.spi.ScalarReturn;
/**
* @author Steve Ebersole
*/
public class ReturnGraphVisitor {
private final ReturnGraphVisitationStrategy strategy;
public ReturnGraphVisitor(ReturnGraphVisitationStrategy strategy) {
this.strategy = strategy;
}
public void visit(Return... rootReturns) {
for ( Return rootReturn : rootReturns ) {
visitRootReturn( rootReturn );
}
}
public void visit(List<? extends Return> rootReturns) {
for ( Return rootReturn : rootReturns ) {
visitRootReturn( rootReturn );
}
}
private void visitRootReturn(Return rootReturn) {
strategy.startingRootReturn( rootReturn );
if ( org.hibernate.loader.plan.spi.ScalarReturn.class.isInstance( rootReturn ) ) {
strategy.handleScalarReturn( (ScalarReturn) rootReturn );
}
else {
visitNonScalarRootReturn( rootReturn );
}
strategy.finishingRootReturn( rootReturn );
}
private void visitNonScalarRootReturn(Return rootReturn) {
if ( EntityReturn.class.isInstance( rootReturn ) ) {
strategy.handleEntityReturn( (EntityReturn) rootReturn );
visitFetches( (EntityReturn) rootReturn );
}
else if ( CollectionReturn.class.isInstance( rootReturn ) ) {
strategy.handleCollectionReturn( (CollectionReturn) rootReturn );
final CollectionReturn collectionReturn = (CollectionReturn) rootReturn;
visitFetches( collectionReturn.getIndexGraph() );
visitFetches( collectionReturn.getElementGraph() );
}
else {
throw new IllegalStateException(
"Unexpected return type encountered; expecting a non-scalar root return, but found " +
rootReturn.getClass().getName()
);
}
}
private void visitFetches(FetchOwner fetchOwner) {
if ( fetchOwner != null ) {
strategy.startingFetches( fetchOwner );
for ( Fetch fetch : fetchOwner.getFetches() ) {
visitFetch( fetch );
}
strategy.finishingFetches( fetchOwner );
}
}
private void visitFetch(Fetch fetch) {
if ( EntityFetch.class.isInstance( fetch ) ) {
strategy.startingEntityFetch( (EntityFetch) fetch );
visitFetches( (EntityFetch) fetch );
strategy.finishingEntityFetch( (EntityFetch) fetch );
}
else if ( CollectionFetch.class.isInstance( fetch ) ) {
strategy.startingCollectionFetch( (CollectionFetch) fetch );
visitFetches( ( (CollectionFetch) fetch ).getIndexGraph() );
visitFetches( ( (CollectionFetch) fetch ).getElementGraph() );
strategy.finishingCollectionFetch( (CollectionFetch) fetch );
}
else if ( CompositeFetch.class.isInstance( fetch ) ) {
strategy.startingCompositeFetch( (CompositeFetch) fetch );
visitFetches( (CompositeFetch) fetch );
strategy.finishingCompositeFetch( (CompositeFetch) fetch );
}
else {
throw new IllegalStateException(
"Unexpected return type encountered; expecting a fetch return, but found " +
fetch.getClass().getName()
);
}
}
}