/***
 * Copyright (c) 2009 Caelum - www.caelum.com.br/opensource All rights reserved.
 * 
 * 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 br.com.caelum.vraptor.serialization.xstream;

import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import br.com.caelum.vraptor.ioc.ApplicationScoped;
import br.com.caelum.vraptor.ioc.Component;

import com.google.common.base.Objects;
import com.google.common.collect.Lists;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.SingleValueConverter;

/**
 * Component used to scan all XStream converters
 *
 * @author Rafael Viana
 * @since 3.4.0
 */
@Component
public class XStreamConverters {

	private final List<Converter> converters;
	private final List<SingleValueConverter> singleValueConverters;
	
	private static final Logger logger = LoggerFactory.getLogger(XStreamConverters.class);

	/**
	 * for DI purposes
	 */
	@Component @ApplicationScoped
	public static class NullConverter implements SingleValueConverter {
	public String toString(Object o) {return null;}

	public Object fromString(String s) {return null;}

	public boolean canConvert(Class aClass) {return false;}
	}

	public XStreamConverters(List<Converter> converters, List<SingleValueConverter> singleValueConverters)
	{
		this.converters = Objects.firstNonNull(converters, Lists.<Converter>newArrayList());
		this.singleValueConverters = Objects.firstNonNull(singleValueConverters, Lists.<SingleValueConverter>newArrayList());
	}
	
	/**
	 * Method used to register all the XStream converters scanned to a XStream instance
	 * @param xstream
	 */
	public void registerComponents(XStream xstream)
	{
		for(Converter converter : converters)
		{
			xstream.registerConverter(converter);
			logger.debug("registered Xstream converter for {}", converter.getClass().getName());
		}
		
		for(SingleValueConverter converter : singleValueConverters)
		{
			xstream.registerConverter(converter);
			logger.debug("registered Xstream converter for {}", converter.getClass().getName());
		}
	}
	
}