com.thoughtworks.xstream.core.TreeMarshaller Maven / Gradle / Ivy

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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.thoughtworks.xstream.core;

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

import java.util.Iterator;

@SuppressWarnings({"rawtypes", "deprecation"})
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;
	}

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

	public void convertAnother(Object item, Converter converter) {
		if (converter == null) {
			converter = converterLookup.lookupConverterForType(item.getClass());
		} else {
			if (!converter.canConvert(item.getClass())) {
				RuntimeException e = new RuntimeException("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)) {
			RuntimeException 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();
		}
	}

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

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

	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 RuntimeException { 
		private static final long serialVersionUID = 1L;

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