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/*
 * Copyright (C) 2004, 2005, 2006 Joe Walnes.
 * Copyright (C) 2006, 2007, 2008, 2009, 2011, 2018 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.ErrorReporter;
import com.feilong.lib.xstream.converters.ErrorWriter;
import com.feilong.lib.xstream.converters.UnmarshallingContext;
import com.feilong.lib.xstream.core.util.FastStack;
import com.feilong.lib.xstream.core.util.HierarchicalStreams;
import com.feilong.lib.xstream.core.util.PrioritizedList;
import com.feilong.lib.xstream.io.HierarchicalStreamReader;
import com.feilong.lib.xstream.mapper.Mapper;

public class TreeUnmarshaller implements UnmarshallingContext{

    private Object                     root;

    protected HierarchicalStreamReader reader;

    private ConverterLookup            converterLookup;

    private Mapper                     mapper;

    private FastStack                  types          = new FastStack(16);

    private DataHolder                 dataHolder;

    private final PrioritizedList      validationList = new PrioritizedList();

    public TreeUnmarshaller(Object root, HierarchicalStreamReader reader, ConverterLookup converterLookup, Mapper mapper){
        this.root = root;
        this.reader = reader;
        this.converterLookup = converterLookup;
        this.mapper = mapper;
    }

    @Override
    public Object convertAnother(Object parent,Class type){
        return convertAnother(parent, type, null);
    }

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

    protected Object convert(Object parent,Class type,Converter converter){
        types.push(type);
        try{
            return converter.unmarshal(reader, this);
        }catch (final ConversionException conversionException){
            addInformationTo(conversionException, type, converter, parent);
            throw conversionException;
        }catch (RuntimeException e){
            ConversionException conversionException = new ConversionException(e);
            addInformationTo(conversionException, type, converter, parent);
            throw conversionException;
        }finally{
            types.popSilently();
        }
    }

    private void addInformationTo(ErrorWriter errorWriter,Class type,Converter converter,Object parent){
        errorWriter.add("class", type.getName());
        errorWriter.add("required-type", getRequiredType().getName());
        errorWriter.add("converter-type", converter.getClass().getName());
        if (converter instanceof ErrorReporter){
            ((ErrorReporter) converter).appendErrors(errorWriter);
        }
        if (parent instanceof ErrorReporter){
            ((ErrorReporter) parent).appendErrors(errorWriter);
        }
        reader.appendErrors(errorWriter);
    }

    @Override
    public void addCompletionCallback(Runnable work,int priority){
        validationList.add(work, priority);
    }

    @Override
    public Object currentObject(){
        return types.size() == 1 ? root : null;
    }

    @Override
    public Class getRequiredType(){
        return (Class) types.peek();
    }

    @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();
        }
    }

    public Object start(DataHolder dataHolder){
        this.dataHolder = dataHolder;
        Class type = HierarchicalStreams.readClassType(reader, mapper);
        Object result = convertAnother(null, type);
        Iterator validations = validationList.iterator();
        while (validations.hasNext()){
            Runnable runnable = (Runnable) validations.next();
            runnable.run();
        }
        return result;
    }

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

}