EDIT

// $Id$

/**

 * 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.featuretree;

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.description.FeatureNode;

import eu.etaxonomy.taxeditor.store.CdmStore;

/**

 * <p>FeatureNodeTransfer class.</p>

 *

 * @author n.hoffmann

 * @created Aug 5, 2010

 * @version 1.0

 */

public class FeatureNodeTransfer extends ByteArrayTransfer {

	private static FeatureNodeTransfer instance = new FeatureNodeTransfer();

	private static final String TYPE_NAME = "featureNode-transfer-format";

	private static final int TYPEID = registerType(TYPE_NAME);

	/**

	 * <p>Getter for the field <code>instance</code>.</p>

	 *

	 * @return a {@link eu.etaxonomy.taxeditor.featuretree.FeatureNodeTransfer} object.

	 */

	public static synchronized FeatureNodeTransfer getInstance() {

		return instance;

	}

	private FeatureNodeTransfer() {

	}

	/** {@inheritDoc} */

	@Override

	protected int[] getTypeIds() {

		return new int[] { TYPEID };

	}

	/** {@inheritDoc} */

	@Override

	protected String[] getTypeNames() {

		return new String[] { TYPE_NAME };

	}

	/*

	 * Method declared on Transfer.

	 */

	/** {@inheritDoc} */

	protected void javaToNative(Object object, TransferData transferData) {

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

		if (bytes != null)

			super.javaToNative(bytes, transferData);

	}

	/*

	 * Method declared on Transfer.

	 */

	/** {@inheritDoc} */

	protected Object nativeToJava(TransferData transferData) {

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

		return fromByteArray(bytes);

	}

	/**

	 * <p>toByteArray</p>

	 *

	 * @param featureNodes an array of {@link eu.etaxonomy.cdm.model.description.FeatureNode} objects.

	 * @return an array of byte.

	 */

	protected byte[] toByteArray(FeatureNode[] featureNodes) {

		/**

		 * Transfer data is an array of gadgets. Serialized version is: (int)

		 * number of gadgets (Gadget) gadget 1 (Gadget) gadget 2 ... repeat for

		 * each subsequent gadget see writeGadget for the (Gadget) format.

		 */

		ByteArrayOutputStream byteOut = new ByteArrayOutputStream();

		DataOutputStream out = new DataOutputStream(byteOut);

		byte[] bytes = null;

		try {

			for(FeatureNode featureNode : featureNodes){

				writeFeatureNode(featureNode, out);

			}

			out.close();

			bytes = byteOut.toByteArray();

		} catch (IOException e) {

			// when in doubt send nothing

		}

		return bytes;

	}

	/**

	 * <p>fromByteArray</p>

	 *

	 * @param bytes an array of byte.

	 * @return an array of {@link eu.etaxonomy.cdm.model.description.FeatureNode} objects.

	 */

	protected FeatureNode[] fromByteArray(byte[] bytes) {

		DataInputStream in = new DataInputStream(

				new ByteArrayInputStream(bytes));

		try {

			List<FeatureNode> featureNodes = new ArrayList<FeatureNode>();

			try{

				while(true){

					featureNodes.add(readFeatureNode(in));

				}

			}catch(EOFException e){

				return featureNodes.toArray(new FeatureNode[]{});

			}

		} catch (IOException e) {

			return null;

		}

	}

	/**

	 * Reads and returns a single featureNode from the given stream.

	 */

	private FeatureNode readFeatureNode(DataInputStream dataIn) throws IOException {

		UUID uuid = UUID.fromString(dataIn.readUTF());

		FeatureNode featureNode = CdmStore.getFeatureNodeService().load(uuid);

		return featureNode;

	}

	/**

	 * Writes the given featureNode to the stream.

	 */

	private void writeFeatureNode(FeatureNode featureNode,

			DataOutputStream dataOut) throws IOException {

		dataOut.writeUTF(featureNode.getUuid().toString());

	}

}