arrayconverter.java

xstream是一个把java object序列化成xml文件的开源库,轻便好用

package com.thoughtworks.xstream.converters.collections;

import com.thoughtworks.xstream.alias.ClassMapper;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.mapper.Mapper;

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

/**
 * Converts an array of objects or primitives to XML, using
 * a nested child element for each item.
 *
 * @author Joe Walnes
 */
public class ArrayConverter extends AbstractCollectionConverter {

    /**
     * @deprecated As of 1.1.1, use other constructor.
     */
    public ArrayConverter(ClassMapper classMapper, String classAttributeIdentifier) {
        super(classMapper, classAttributeIdentifier);
    }

    public ArrayConverter(Mapper mapper) {
        super(mapper);
    }

    public boolean canConvert(Class type) {
        return type.isArray();
    }

    public void marshal(Object source, HierarchicalStreamWriter writer, MarshallingContext context) {
        int length = Array.getLength(source);
        for (int i = 0; i < length; i++) {
            Object item = Array.get(source, i);
            writeItem(item, context, writer);
        }
    }

    public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {
        // read the items from xml into a list
        List items = new ArrayList();
        while (reader.hasMoreChildren()) {
            reader.moveDown();
            Object item = readItem(reader, context, null); // TODO: arg, what should replace null?
            items.add(item);
            reader.moveUp();
        }
        // now convertAnother the list into an array
        // (this has to be done as a separate list as the array size is not
        //  known until all items have been read)
        Object array = Array.newInstance(context.getRequiredType().getComponentType(), items.size());
        int i = 0;
        for (Iterator iterator = items.iterator(); iterator.hasNext();) {
            Array.set(array, i++, iterator.next());
        }
        return array;
    }
}