001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  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 */
017package org.apache.commons.beanutils.converters;
018
019/**
020 * {@link org.apache.commons.beanutils.Converter}
021 * implementation that converts an incoming
022 * object into a <code>java.lang.String</code> object.
023 * <p>
024 * Note that ConvertUtils really is designed to do string->object conversions,
025 * and offers very little support for object->string conversions. The
026 * ConvertUtils/ConvertUtilsBean methods only select a converter to apply
027 * based upon the target type being converted to, and generally assume that
028 * the input is a string (by calling its toString method if needed).
029 * <p>
030 * This class is therefore just a dummy converter that converts its input
031 * into a string by calling the input object's toString method and returning
032 * that value.
033 * <p>
034 * It is possible to replace this converter with something that has a big
035 * if/else statement that selects behaviour based on the real type of the
036 * object being converted (or possibly has a map of converters, and looks
037 * them up based on the class of the input object). However this is not part
038 * of the existing ConvertUtils framework.
039 *  
040 *
041 * @author Craig R. McClanahan
042 * @version $Revision: 690380 $ $Date: 2008-08-29 21:04:38 +0100 (Fri, 29 Aug 2008) $
043 * @since 1.3
044 */
045public final class StringConverter extends AbstractConverter {
046
047
048    /**
049     * Construct a <b>java.lang.String</b> <i>Converter</i> that throws
050     * a <code>ConversionException</code> if an error occurs.
051     */
052    public StringConverter() {
053        super();
054    }
055
056    /**
057     * Construct a <b>java.lang.String</b> <i>Converter</i> that returns
058     * a default value if an error occurs.
059     *
060     * @param defaultValue The default value to be returned
061     * if the value to be converted is missing or an error
062     * occurs converting the value.
063     */
064    public StringConverter(Object defaultValue) {
065        super(defaultValue);
066    }
067
068    /**
069     * Return the default type this <code>Converter</code> handles.
070     *
071     * @return The default type this <code>Converter</code> handles.
072     * @since 1.8.0
073     */
074    protected Class getDefaultType() {
075        return String.class;
076    }
077
078    /**
079     * Convert the specified input object into an output object of the
080     * specified type.
081     *
082     * @param type Data type to which this value should be converted.
083     * @param value The input value to be converted.
084     * @return The converted value.
085     * @throws Throwable if an error occurs converting to the specified type
086     * @since 1.8.0
087     */
088    protected Object convertToType(Class type, Object value) throws Throwable {
089        return value.toString();
090    }
091
092
093}