QuerySpaceHelper.java

/*
 * 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.loader.plan.build.internal.spaces;

import org.hibernate.engine.FetchStrategy;
import org.hibernate.engine.FetchStyle;
import org.hibernate.engine.FetchTiming;
import org.hibernate.loader.plan.build.spi.ExpandingCollectionQuerySpace;
import org.hibernate.loader.plan.build.spi.ExpandingCompositeQuerySpace;
import org.hibernate.loader.plan.build.spi.ExpandingEntityQuerySpace;
import org.hibernate.loader.plan.build.spi.ExpandingQuerySpace;
import org.hibernate.loader.plan.spi.JoinDefinedByMetadata;
import org.hibernate.persister.collection.CollectionPersister;
import org.hibernate.persister.entity.EntityPersister;
import org.hibernate.persister.entity.Queryable;
import org.hibernate.persister.walking.spi.AssociationAttributeDefinition;
import org.hibernate.persister.walking.spi.AttributeDefinition;
import org.hibernate.persister.walking.spi.WalkingException;
import org.hibernate.type.CollectionType;
import org.hibernate.type.CompositeType;
import org.hibernate.type.EntityType;

/**
 * @author Gail Badner
 */
public class QuerySpaceHelper {
	/**
	 * Singleton access
	 */
	public static final QuerySpaceHelper INSTANCE = new QuerySpaceHelper();

	private QuerySpaceHelper() {
	}

	public ExpandingEntityQuerySpace makeEntityQuerySpace(
			ExpandingQuerySpace lhsQuerySpace,
			AssociationAttributeDefinition attribute,
			String querySpaceUid,
			FetchStrategy fetchStrategy) {
		final EntityType fetchedType = (EntityType) attribute.getType();
		final EntityPersister fetchedPersister = attribute.toEntityDefinition().getEntityPersister();

		if ( fetchedPersister == null ) {
			throw new WalkingException(
					String.format(
							"Unable to locate EntityPersister [%s] for fetch [%s]",
							fetchedType.getAssociatedEntityName(),
							attribute.getName()
					)
			);
		}
		// TODO: Queryable.isMultiTable() may be more broad than it needs to be...
		final boolean isMultiTable = Queryable.class.cast( fetchedPersister ).isMultiTable();
		final boolean required = lhsQuerySpace.canJoinsBeRequired() && !isMultiTable && !attribute.isNullable();

		return makeEntityQuerySpace(
				lhsQuerySpace,
				fetchedPersister,
				attribute.getName(),
				(EntityType) attribute.getType(),
				querySpaceUid,
				required,
				shouldIncludeJoin( fetchStrategy )
		);
	}

	public ExpandingEntityQuerySpace makeEntityQuerySpace(
			ExpandingQuerySpace lhsQuerySpace,
			EntityPersister fetchedPersister,
			String attributeName,
			EntityType attributeType,
			String querySpaceUid,
			boolean required,
			boolean shouldIncludeJoin) {

		final ExpandingEntityQuerySpace rhs = lhsQuerySpace.getExpandingQuerySpaces().makeEntityQuerySpace(
				querySpaceUid,
				fetchedPersister,
				required
		);

		if ( shouldIncludeJoin ) {
			final JoinDefinedByMetadata join = JoinHelper.INSTANCE.createEntityJoin(
					lhsQuerySpace,
					attributeName,
					rhs,
					required,
					attributeType,
					fetchedPersister.getFactory()
			);
			lhsQuerySpace.addJoin( join );
		}

		return rhs;
	}

	public ExpandingCompositeQuerySpace makeCompositeQuerySpace(
			ExpandingQuerySpace lhsQuerySpace,
			AttributeDefinition attributeDefinition,
			String querySpaceUid,
			boolean shouldIncludeJoin) {
		final boolean required = lhsQuerySpace.canJoinsBeRequired() && !attributeDefinition.isNullable();
		return makeCompositeQuerySpace(
				lhsQuerySpace,
				new CompositePropertyMapping(
						(CompositeType) attributeDefinition.getType(),
						lhsQuerySpace.getPropertyMapping(),
						attributeDefinition.getName()
				),
				attributeDefinition.getName(),
				(CompositeType) attributeDefinition.getType(),
				querySpaceUid,
				required,
				shouldIncludeJoin
		);
	}

	public ExpandingCompositeQuerySpace makeCompositeQuerySpace(
			ExpandingQuerySpace lhsQuerySpace,
			CompositePropertyMapping compositePropertyMapping,
			String attributeName,
			CompositeType attributeType,
			String querySpaceUid,
			boolean required,
			boolean shouldIncludeJoin) {

		final ExpandingCompositeQuerySpace rhs = lhsQuerySpace.getExpandingQuerySpaces().makeCompositeQuerySpace(
				querySpaceUid,
				compositePropertyMapping,
				required
		);

		if ( shouldIncludeJoin ) {
			final JoinDefinedByMetadata join = JoinHelper.INSTANCE.createCompositeJoin(
					lhsQuerySpace,
					attributeName,
					rhs,
					required,
					attributeType
			);
			lhsQuerySpace.addJoin( join );
		}

		return rhs;
	}

	public ExpandingCollectionQuerySpace makeCollectionQuerySpace(
			ExpandingQuerySpace lhsQuerySpace,
			AssociationAttributeDefinition attributeDefinition,
			String querySpaceUid,
			FetchStrategy fetchStrategy) {

		final CollectionType fetchedType = (CollectionType) attributeDefinition.getType();
		final CollectionPersister fetchedPersister = attributeDefinition.toCollectionDefinition()
				.getCollectionPersister();

		if ( fetchedPersister == null ) {
			throw new WalkingException(
					String.format(
							"Unable to locate CollectionPersister [%s] for fetch [%s]",
							fetchedType.getRole(),
							attributeDefinition.getName()
					)
			);
		}

		final boolean required = lhsQuerySpace.canJoinsBeRequired() && !attributeDefinition.isNullable();

		final ExpandingCollectionQuerySpace rhs = lhsQuerySpace.getExpandingQuerySpaces().makeCollectionQuerySpace(
				querySpaceUid,
				fetchedPersister,
				required
		);

		if ( shouldIncludeJoin( fetchStrategy ) ) {
			final JoinDefinedByMetadata join = JoinHelper.INSTANCE.createCollectionJoin(
					lhsQuerySpace,
					attributeDefinition.getName(),
					rhs,
					required,
					(CollectionType) attributeDefinition.getType(),
					fetchedPersister.getFactory()
			);
			lhsQuerySpace.addJoin( join );
		}

		return rhs;
	}

	public boolean shouldIncludeJoin(FetchStrategy fetchStrategy) {
		return fetchStrategy.getTiming() == FetchTiming.IMMEDIATE && fetchStrategy.getStyle() == FetchStyle.JOIN;
	}
}