/*
 * Copyright 2002-2013 the original author or authors.
 *
 * Licensed 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.springframework.oxm.xstream;

import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;

/**
 * XStream {@link Converter} that supports all classes, but throws exceptions for
 * (un)marshalling.
 * <p>Main purpose of this class is to
 * {@linkplain com.thoughtworks.xstream.XStream#registerConverter(com.thoughtworks.xstream.converters.Converter, int) register}
 * this converter as a catchall last converter with a
 * {@linkplain com.thoughtworks.xstream.XStream#PRIORITY_NORMAL normal}
 * or higher priority, in addition to converters that explicitly support the domain
 * classes that should be supported. As a result, default XStream converters with lower
 * priorities and possible security vulnerabilities do not get invoked.
 * <p>For instance:</p>
 * <pre class="code">
 * XStreamMarshaller unmarshaller = new XStreamMarshaller();
 * unmarshaller.getXStream().registerConverter(new MyDomainClassConverter(), XStream.PRIORITY_VERY_HIGH);
 * unmarshaller.getXStream().registerConverter(new CatchAllConverter(), XStream.PRIORITY_NORMAL);
 * MyDomainClass o = unmarshaller.unmarshal(source);
 * </pre
 *
 * @author Arjen Poutsma
 * @since 4.0
 */
public class CatchAllConverter implements Converter {

	@Override
	public boolean canConvert(Class type) {
		return true;
	}

	@Override
	public void marshal(Object source, HierarchicalStreamWriter writer,
			MarshallingContext context) {
		throw new UnsupportedOperationException("marshalling not supported");
	}

	@Override
	public Object unmarshal(HierarchicalStreamReader reader,
			UnmarshallingContext context) {
		throw new UnsupportedOperationException("unmarshalling not supported");
	}
}
