ArrayConverter.java

package student.web.internal.converters;

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.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.UUID;
import student.web.internal.Snapshot;
import student.web.internal.PersistentStorageManager.FakePrintWriter;


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

    /**
     * Create a new ArrayConverter.
     * @param mapper The mapper to use.
     */
    public ArrayConverter(Mapper mapper)
    {
        super(mapper);
    }


    @SuppressWarnings("rawtypes")
    public boolean canConvert(Class type)
    {
        if (type == null)
        {
            return false;
        }
        return type.isArray();
    }


    public void marshal(
        Object source,
        HierarchicalStreamWriter writer,
        MarshallingContext context)
    {
        Class<?> arrayElementType = source.getClass().getComponentType();
        UUID id = Snapshot.lookupId(source, false);
        List<Object> localCollection;
        if (arrayElementType.equals(byte.class))
        {
            localCollection =
                new ArrayList<Object>(Arrays.asList((byte[])source));
            super.marshal0(id, source, writer, context, localCollection);
        }
        else if (arrayElementType.equals(short.class))
        {
            localCollection =
                new ArrayList<Object>(Arrays.asList((short[])source));
            super.marshal0(id, source, writer, context, localCollection);
        }
        else if (arrayElementType.equals(int.class))
        {
            localCollection =
                new ArrayList<Object>(Arrays.asList((int[])source));
            super.marshal0(id, source, writer, context, localCollection);
        }
        else if (arrayElementType.equals(long.class))
        {
            localCollection =
                new ArrayList<Object>(Arrays.asList((long[])source));
            super.marshal0(id, source, writer, context, localCollection);
        }
        else if (arrayElementType.equals(float.class))
        {
            localCollection =
                new ArrayList<Object>(Arrays.asList((float[])source));
            super.marshal0(id, source, writer, context, localCollection);
        }
        else if (arrayElementType.equals(double.class))
        {
            localCollection =
                new ArrayList<Object>(Arrays.asList((double[])source));
            super.marshal0(id, source, writer, context, localCollection);
        }
        else if (arrayElementType.equals(char.class))
        {
            localCollection =
                new ArrayList<Object>(Arrays.asList((char[])source));
            super.marshal0(id, source, writer, context, localCollection);
        }
        else if (arrayElementType.equals(boolean.class))
        {
            localCollection =
                new ArrayList<Object>(Arrays.asList((boolean[])source));
            super.marshal0(id, source, writer, context, localCollection);
        }
        else
        {
            localCollection =
                new ArrayList<Object>(Arrays.asList((Object[])source));
            super.marshal0(id, source, writer, context, localCollection);
        }
        for (int i = 0; i < localCollection.size(); i++)
        {
            Array.set(source, i, localCollection.get(i));
        }
        if (!(writer instanceof FakePrintWriter))
        {
            Snapshot.getLocal().resolveObject(id, source, localCollection);
        }

    }


    public Object unmarshal(
        HierarchicalStreamReader reader,
        UnmarshallingContext context)
    {
        UUID idAttr = UUID.fromString(reader.getAttribute(
            XMLConstants.ID_ATTRIBUTE));
        Collection<Object> toPopulate = new ArrayList<Object>();
        super.populateCollection(reader, context, toPopulate, null);
        Object array = Array.newInstance( context.getRequiredType()
            .getComponentType(), toPopulate.size());
        int i = 0;
        for (Iterator<Object> iterator = toPopulate.iterator();
             iterator.hasNext();
             /* no increment needed */)
        {
            Array.set(array, i++, iterator.next());
        }
        Snapshot.getLocal().resolveObject(idAttr, array, toPopulate);
        return array;
    }
}