Hibernate example source code file (AbstractEmptinessExpression.java)

This example Hibernate source code file (AbstractEmptinessExpression.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Hibernate tags/keywords

abstractemptinessexpression, criteriaquery, hibernateexception, hibernateexception, no_values, propertymapping, queryablecollection, queryablecollection, queryexception, sessionfactoryimplementor, string, string, typedvalue, typedvalue

The Hibernate AbstractEmptinessExpression.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC 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 Middleware LLC.
 *
 * 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.criterion;
import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.MappingException;
import org.hibernate.QueryException;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.engine.spi.TypedValue;
import org.hibernate.persister.collection.QueryableCollection;
import org.hibernate.persister.entity.Loadable;
import org.hibernate.persister.entity.PropertyMapping;
import org.hibernate.sql.ConditionFragment;
import org.hibernate.type.CollectionType;
import org.hibernate.type.Type;

/**
 * Implementation of AbstractEmptinessExpression.
 *
 * @author Steve Ebersole
 */
public abstract class AbstractEmptinessExpression implements Criterion {

	private static final TypedValue[] NO_VALUES = new TypedValue[0];

	protected final String propertyName;

	protected AbstractEmptinessExpression(String propertyName) {
		this.propertyName = propertyName;
	}

	protected abstract boolean excludeEmpty();

	public final String toSqlString(Criteria criteria, CriteriaQuery criteriaQuery) throws HibernateException {
		String entityName = criteriaQuery.getEntityName( criteria, propertyName );
		String actualPropertyName = criteriaQuery.getPropertyName( propertyName );
		String sqlAlias = criteriaQuery.getSQLAlias( criteria, propertyName );

		SessionFactoryImplementor factory = criteriaQuery.getFactory();
		QueryableCollection collectionPersister = getQueryableCollection( entityName, actualPropertyName, factory );

		String[] collectionKeys = collectionPersister.getKeyColumnNames();
		String[] ownerKeys = ( ( Loadable ) factory.getEntityPersister( entityName ) ).getIdentifierColumnNames();

		String innerSelect = "(select 1 from " + collectionPersister.getTableName()
		        + " where "
		        + new ConditionFragment().setTableAlias( sqlAlias ).setCondition( ownerKeys, collectionKeys ).toFragmentString()
		        + ")";

		return excludeEmpty()
		        ? "exists " + innerSelect
		        : "not exists " + innerSelect;
	}


	protected QueryableCollection getQueryableCollection(String entityName, String propertyName, SessionFactoryImplementor factory)
	        throws HibernateException {
		PropertyMapping ownerMapping = ( PropertyMapping ) factory.getEntityPersister( entityName );
		Type type = ownerMapping.toType( propertyName );
		if ( !type.isCollectionType() ) {
			throw new MappingException(
			        "Property path [" + entityName + "." + propertyName + "] does not reference a collection"
			);
		}

		String role = ( ( CollectionType ) type ).getRole();
		try {
			return ( QueryableCollection ) factory.getCollectionPersister( role );
		}
		catch ( ClassCastException cce ) {
			throw new QueryException( "collection role is not queryable: " + role );
		}
		catch ( Exception e ) {
			throw new QueryException( "collection role not found: " + role );
		}
	}

	public final TypedValue[] getTypedValues(Criteria criteria, CriteriaQuery criteriaQuery)
	        throws HibernateException {
		return NO_VALUES;
	}

	public final String toString() {
		return propertyName + ( excludeEmpty() ? " is not empty" : " is empty" );
	}
}