    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     */
    017    package 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     */
    045    public 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    }