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/*
 * Copyright (C) 2004, 2005, 2006 Joe Walnes.
 * Copyright (C) 2006, 2007, 2009, 2011 XStream Committers.
 * All rights reserved.
 *
 * The software in this package is published under the terms of the BSD
 * style license a copy of which has been included with this distribution in
 * the LICENSE.txt file.
 * 
 * Created on 15. March 2004 by Joe Walnes
 */
package com.feilong.lib.xstream.core;

import java.util.Iterator;

import com.feilong.lib.xstream.converters.ConversionException;
import com.feilong.lib.xstream.converters.Converter;
import com.feilong.lib.xstream.converters.ConverterLookup;
import com.feilong.lib.xstream.converters.DataHolder;
import com.feilong.lib.xstream.converters.MarshallingContext;
import com.feilong.lib.xstream.core.util.ObjectIdDictionary;
import com.feilong.lib.xstream.io.ExtendedHierarchicalStreamWriterHelper;
import com.feilong.lib.xstream.io.HierarchicalStreamWriter;
import com.feilong.lib.xstream.mapper.Mapper;

public class TreeMarshaller implements MarshallingContext{

    protected HierarchicalStreamWriter writer;

    protected ConverterLookup          converterLookup;

    private Mapper                     mapper;

    private ObjectIdDictionary         parentObjects = new ObjectIdDictionary();

    private DataHolder                 dataHolder;

    public TreeMarshaller(HierarchicalStreamWriter writer, ConverterLookup converterLookup, Mapper mapper){
        this.writer = writer;
        this.converterLookup = converterLookup;
        this.mapper = mapper;
    }

    @Override
    public void convertAnother(Object item){
        convertAnother(item, null);
    }

    @Override
    public void convertAnother(Object item,Converter converter){
        if (converter == null){
            converter = converterLookup.lookupConverterForType(item.getClass());
        }else{
            if (!converter.canConvert(item.getClass())){
                ConversionException e = new ConversionException("Explicit selected converter cannot handle item");
                e.add("item-type", item.getClass().getName());
                e.add("converter-type", converter.getClass().getName());
                throw e;
            }
        }
        convert(item, converter);
    }

    protected void convert(Object item,Converter converter){
        if (parentObjects.containsId(item)){
            ConversionException e = new CircularReferenceException("Recursive reference to parent object");
            e.add("item-type", item.getClass().getName());
            e.add("converter-type", converter.getClass().getName());
            throw e;
        }
        parentObjects.associateId(item, "");
        converter.marshal(item, writer, this);
        parentObjects.removeId(item);
    }

    public void start(Object item,DataHolder dataHolder){
        this.dataHolder = dataHolder;
        if (item == null){
            writer.startNode(mapper.serializedClass(null));
            writer.endNode();
        }else{
            ExtendedHierarchicalStreamWriterHelper.startNode(writer, mapper.serializedClass(item.getClass()), item.getClass());
            convertAnother(item);
            writer.endNode();
        }
    }

    @Override
    public Object get(Object key){
        lazilyCreateDataHolder();
        return dataHolder.get(key);
    }

    @Override
    public void put(Object key,Object value){
        lazilyCreateDataHolder();
        dataHolder.put(key, value);
    }

    @Override
    public Iterator keys(){
        lazilyCreateDataHolder();
        return dataHolder.keys();
    }

    private void lazilyCreateDataHolder(){
        if (dataHolder == null){
            dataHolder = new MapBackedDataHolder();
        }
    }

    protected Mapper getMapper(){
        return this.mapper;
    }

    public static class CircularReferenceException extends ConversionException{

        /**
         * 
         */
        private static final long serialVersionUID = -6229538552445227832L;

        public CircularReferenceException(String msg){
            super(msg);
        }
    }
}