EDIT

/**

* Copyright (C) 2007 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.taxeditor.model;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.DataInputStream;

import java.io.DataOutputStream;

import java.io.EOFException;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import java.util.UUID;

import org.eclipse.swt.dnd.ByteArrayTransfer;

import org.eclipse.swt.dnd.TransferData;

import eu.etaxonomy.cdm.model.common.ICdmBase;

/**

 * @author n.hoffmann

 * @created Feb 8, 2011

 * @version 1.0

 */

public abstract class CdmObjectTransfer<T extends ICdmBase> extends ByteArrayTransfer {

	@Override

	protected void javaToNative(Object object, TransferData transferData) {

		if (object != null){

			byte[] bytes = toByteArray((T[]) object);

			if (bytes != null) {

                super.javaToNative(bytes, transferData);

            }

		}

	}

	@Override

	protected Object nativeToJava(TransferData transferData) {

		byte[] bytes = (byte[]) super.nativeToJava(transferData);

		if (bytes != null){

			return fromByteArray(bytes);

		}

		return null;

	}

	protected byte[] toByteArray(T[] elements) {

		ByteArrayOutputStream byteOut = new ByteArrayOutputStream();

		DataOutputStream out = new DataOutputStream(byteOut);

		byte[] bytes = null;

		try {

			for(T element : elements){

				writeElementUuid(element, out);

			}

			out.close();

			bytes = byteOut.toByteArray();

		} catch (IOException e) {

			// when in doubt send nothing

		}

		return bytes;

	}

	private void writeElementUuid(T element, DataOutputStream out) throws IOException {

		out.writeUTF(element.getUuid().toString());

	}

	protected Object fromByteArray(byte[] bytes) {

		DataInputStream in = new DataInputStream(

				new ByteArrayInputStream(bytes));

		try {

			List<T> elements = new ArrayList<T>();

			try{

				while(true){

					UUID uuid = readElementUuid(in);

					elements.add(loadElement(uuid));

				}

			}catch(EOFException e){

				return elements.toArray();

			}

		} catch (IOException e) {

			return null;

		}

	}

	public abstract T loadElement(UUID uuid);

	public UUID readElementUuid(DataInputStream in) throws IOException{

		return UUID.fromString(in.readUTF());

	}

}