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/*
 * Copyright (C) 2013 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 03. December 2013 by Joerg Schaible
 */
package com.feilong.lib.xstream.converters.extended;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.List;

import com.feilong.lib.xstream.converters.Converter;
import com.feilong.lib.xstream.converters.MarshallingContext;
import com.feilong.lib.xstream.converters.UnmarshallingContext;
import com.feilong.lib.xstream.core.util.HierarchicalStreams;
import com.feilong.lib.xstream.core.util.Primitives;
import com.feilong.lib.xstream.io.ExtendedHierarchicalStreamWriterHelper;
import com.feilong.lib.xstream.io.HierarchicalStreamReader;
import com.feilong.lib.xstream.io.HierarchicalStreamWriter;
import com.feilong.lib.xstream.mapper.Mapper;

/**
 * An array converter that uses predefined names for its items.
 * 
 * To be used as local converter.
 * 
 * 
 * @author Jörg Schaible
 * @since 1.4.6
 */
public class NamedArrayConverter implements Converter{

    private final Class  arrayType;

    private final String itemName;

    private final Mapper mapper;

    /**
     * Construct a NamedArrayConverter.
     * 
     * @param arrayType
     * @param mapper
     * @param itemName
     * @since 1.4.6
     */
    public NamedArrayConverter(final Class arrayType, final Mapper mapper, final String itemName){
        if (!arrayType.isArray()){
            throw new IllegalArgumentException(arrayType.getName() + " is not an array");
        }
        this.arrayType = arrayType;
        this.mapper = mapper;
        this.itemName = itemName;
    }

    @Override
    public boolean canConvert(final Class type){
        return type == arrayType;
    }

    @Override
    public void marshal(final Object source,final HierarchicalStreamWriter writer,final MarshallingContext context){
        final int length = Array.getLength(source);
        for (int i = 0; i < length; ++i){
            final Object item = Array.get(source, i);
            final Class itemType = item == null ? Mapper.Null.class
                            : arrayType.getComponentType().isPrimitive() ? Primitives.unbox(item.getClass()) : item.getClass();
            ExtendedHierarchicalStreamWriterHelper.startNode(writer, itemName, itemType);
            if (!itemType.equals(arrayType.getComponentType())){
                final String attributeName = mapper.aliasForSystemAttribute("class");
                if (attributeName != null){
                    writer.addAttribute(attributeName, mapper.serializedClass(itemType));
                }
            }
            if (item != null){
                context.convertAnother(item);
            }
            writer.endNode();
        }
    }

    @Override
    public Object unmarshal(final HierarchicalStreamReader reader,final UnmarshallingContext context){
        final List list = new ArrayList();
        while (reader.hasMoreChildren()){
            reader.moveDown();
            final Object item;
            final String className = HierarchicalStreams.readClassAttribute(reader, mapper);
            final Class itemType = className == null ? arrayType.getComponentType() : mapper.realClass(className);
            if (Mapper.Null.class.equals(itemType)){
                item = null;
            }else{
                item = context.convertAnother(null, itemType);
            }
            list.add(item);
            reader.moveUp();
        }
        final Object array = Array.newInstance(arrayType.getComponentType(), list.size());
        for (int i = 0; i < list.size(); ++i){
            Array.set(array, i, list.get(i));
        }
        return array;
    }

}