org.apache.commons.beanutils.converters.ClassConverter Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.beanutils.converters;
/**
* {@link org.apache.commons.beanutils.Converter} implementaion that handles conversion
* to and from java.lang.Class objects.
*
* The class will be loaded from the thread context class
* loader (if it exists); otherwise the class loader that loaded this class
* will be used.
*
* Can be configured to either return a default value or throw a
* ConversionException if a conversion error occurs.
*
* @version $Id$
* @since 1.4
*/
public final class ClassConverter extends AbstractConverter {
/**
* Construct a java.lang.Class Converter that throws
* a ConversionException if an error occurs.
*/
public ClassConverter() {
super();
}
/**
* Construct a java.lang.Class Converter that returns
* a default value if an error occurs.
*
* @param defaultValue The default value to be returned
* if the value to be converted is missing or an error
* occurs converting the value.
*/
public ClassConverter(final Object defaultValue) {
super(defaultValue);
}
/**
* Return the default type this Converter handles.
*
* @return The default type this Converter handles.
* @since 1.8.0
*/
@Override
protected Class getDefaultType() {
return Class.class;
}
/**
*
Convert a java.lang.Class or object into a String.
*
* @param value The input value to be converted
* @return the converted String value.
* @since 1.8.0
*/
@Override
protected String convertToString(final Object value) {
return (value instanceof Class) ? ((Class)value).getName() : value.toString();
}
/**
* Convert the input object into a java.lang.Class.
*
* @param Target type of the conversion.
* @param type Data type to which this value should be converted.
* @param value The input value to be converted.
* @return The converted value.
* @throws Throwable if an error occurs converting to the specified type
* @since 1.8.0
*/
@Override
protected T convertToType(final Class type, final Object value) throws Throwable {
if (Class.class.equals(type)) {
ClassLoader classLoader = Thread.currentThread()
.getContextClassLoader();
if (classLoader != null) {
try {
return type.cast(classLoader.loadClass(value.toString()));
} catch (final ClassNotFoundException ex) {
// Don't fail, carry on and try this class's class loader
// (see issue# BEANUTILS-263)
}
}
// Try this class's class loader
classLoader = ClassConverter.class.getClassLoader();
return type.cast(classLoader.loadClass(value.toString()));
}
throw conversionException(type, value);
}
}