001    package org.apache.ojb.broker.accesslayer.conversions;
002    
003    /* Copyright 2002-2005 The Apache Software Foundation
004     *
005     * Licensed under the Apache License, Version 2.0 (the "License");
006     * you may not use this file except in compliance with the License.
007     * You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    
018    /**
019     * this implementation of the FieldConversion interface converts
020     * between blank strings ("") and nulls values in the rdbms. This is to make
021     * oracle and SQL Server compatible, as Oracle stores blank strings as nulls,
022     * which makes comparisons on re-materialized objects problematic.
023     * @author              Matthew Baird
024     * @version $Id: BlankString2NullFieldConversion.java,v 1.1 2007-08-24 22:17:31 ewestfal Exp $
025     */
026    public class BlankString2NullFieldConversion implements FieldConversion
027    {
028    
029        /*
030         * @see FieldConversion#javaToSql(Object)
031         */
032        public Object javaToSql(Object source)
033        {
034            if (source instanceof String)
035            {
036                if (((String)source).trim().length() == 0)
037                        return null;
038            }
039            return source;
040        }
041    
042        /*
043         * @see FieldConversion#sqlToJava(Object)
044         */
045        public Object sqlToJava(Object source)
046        {
047            return source;
048        }
049    
050    }