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} implementaion that handles conversion 021 * to and from <b>java.lang.Class</b> objects. 022 * <p> 023 * The class will be loaded from the thread context class 024 * loader (if it exists); otherwise the class loader that loaded this class 025 * will be used. 026 * <p> 027 * Can be configured to either return a <i>default value</i> or throw a 028 * <code>ConversionException</code> if a conversion error occurs. 029 * 030 * @author Tomas Viberg 031 * @version $Revision: 640131 $ $Date: 2008-03-23 02:10:31 +0000 (Sun, 23 Mar 2008) $ 032 * @since 1.4 033 */ 034 public final class ClassConverter extends AbstractConverter { 035 036 /** 037 * Construct a <b>java.lang.Class</b> <i>Converter</i> that throws 038 * a <code>ConversionException</code> if an error occurs. 039 */ 040 public ClassConverter() { 041 super(); 042 } 043 044 /** 045 * Construct a <b>java.lang.Class</b> <i>Converter</i> that returns 046 * a default value if an error occurs. 047 * 048 * @param defaultValue The default value to be returned 049 * if the value to be converted is missing or an error 050 * occurs converting the value. 051 */ 052 public ClassConverter(Object defaultValue) { 053 super(defaultValue); 054 } 055 056 /** 057 * Return the default type this <code>Converter</code> handles. 058 * 059 * @return The default type this <code>Converter</code> handles. 060 */ 061 protected Class getDefaultType() { 062 return Class.class; 063 } 064 065 /** 066 * <p>Convert a java.lang.Class or object into a String.</p> 067 * 068 * @param value The input value to be converted 069 * @return the converted String value. 070 */ 071 protected String convertToString(Object value) { 072 return (value instanceof Class) ? ((Class)value).getName() : value.toString(); 073 } 074 075 /** 076 * <p>Convert the input object into a java.lang.Class.</p> 077 * 078 * @param type Data type to which this value should be converted. 079 * @param value The input value to be converted. 080 * @return The converted value. 081 * @throws Throwable if an error occurs converting to the specified type 082 */ 083 protected Object convertToType(Class type, Object value) throws Throwable { 084 ClassLoader classLoader = 085 Thread.currentThread().getContextClassLoader(); 086 if (classLoader != null) { 087 try { 088 return (classLoader.loadClass(value.toString())); 089 } catch (ClassNotFoundException ex) { 090 // Don't fail, carry on and try this class's class loader 091 // (see issue# BEANUTILS-263) 092 } 093 } 094 095 // Try this class's class loader 096 classLoader = ClassConverter.class.getClassLoader(); 097 return (classLoader.loadClass(value.toString())); 098 } 099 100 }