ConvertFunction.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.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.StandardBasicTypes;
import org.hibernate.type.Type;

/**
 * A Caché defintion of a convert function.
 *
 * @author Jonathan Levinson
 */
public class ConvertFunction implements SQLFunction {
	@Override
	public boolean hasArguments() {
		return true;
	}

	@Override
	public boolean hasParenthesesIfNoArguments() {
		return true;
	}

	@Override
	public Type getReturnType(Type firstArgumentType, Mapping mapping) throws QueryException {
		return StandardBasicTypes.STRING;
	}

	@Override
	public String render(Type firstArgumentType, List args, SessionFactoryImplementor factory) throws QueryException {
		if ( args.size() != 2 && args.size() != 3 ) {
			throw new QueryException( "convert() requires two or three arguments" );
		}

		final String type = (String) args.get( 1 );

		if ( args.size() == 2 ) {
			return "{fn convert(" + args.get( 0 ) + " , " + type + ")}";
		}
		else {
			return "convert(" + args.get( 0 ) + " , " + type + "," + args.get( 2 ) + ")";
		}
	}

}