/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, 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.criterion;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.dialect.function.SQLFunction;
import org.hibernate.dialect.function.SQLFunctionRegistry;
import org.hibernate.type.Type;
/**
* A row count
*
* @author Gavin King
*/
public class RowCountProjection extends SimpleProjection {
private static final List ARGS = java.util.Collections.singletonList( "*" );
@Override
public Type[] getTypes(Criteria criteria, CriteriaQuery criteriaQuery) throws HibernateException {
final Type countFunctionReturnType = getFunction( criteriaQuery ).getReturnType( null, criteriaQuery.getFactory() );
return new Type[] { countFunctionReturnType };
}
@Override
public String toSqlString(Criteria criteria, int position, CriteriaQuery criteriaQuery) throws HibernateException {
return getFunction( criteriaQuery ).render( null, ARGS, criteriaQuery.getFactory() ) + " as y" + position + '_';
}
protected SQLFunction getFunction(CriteriaQuery criteriaQuery) {
final SQLFunctionRegistry sqlFunctionRegistry = criteriaQuery.getFactory().getSqlFunctionRegistry();
final SQLFunction function = sqlFunctionRegistry.findSQLFunction( "count" );
if ( function == null ) {
throw new HibernateException( "Unable to locate count function mapping" );
}
return function;
}
@Override
public String toString() {
return "count(*)";
}
}