/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, 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.dialect.function;
import java.util.List;
import org.hibernate.QueryException;
import org.hibernate.engine.spi.Mapping;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.type.Type;
/**
* Emulation of <tt>coalesce()</tt> on Oracle, using multiple <tt>nvl()</tt> calls
*
* @author Gavin King
*/
public class NvlFunction implements SQLFunction {
public boolean hasArguments() {
return true;
}
public boolean hasParenthesesIfNoArguments() {
return true;
}
public Type getReturnType(Type argumentType, Mapping mapping) throws QueryException {
return argumentType;
}
public String render(Type argumentType, List args, SessionFactoryImplementor factory) throws QueryException {
int lastIndex = args.size()-1;
Object last = args.remove(lastIndex);
if ( lastIndex==0 ) {
return last.toString();
}
Object secondLast = args.get(lastIndex-1);
String nvl = "nvl(" + secondLast + ", " + last + ")";
args.set(lastIndex-1, nvl);
return render( argumentType, args, factory );
}
}