MyTypeTransfer.java

/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.examples.clipboard;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

import org.eclipse.swt.dnd.ByteArrayTransfer;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.dnd.TransferData;

public class MyTypeTransfer extends ByteArrayTransfer {

	private static MyTypeTransfer	_instance	= new MyTypeTransfer();
	private static final int		MYTYPEID	= Transfer.registerType(MyTypeTransfer.MYTYPENAME);
	private static final String		MYTYPENAME	= "name_list";										//$NON-NLS-1$

	public static MyTypeTransfer getInstance() {
		return MyTypeTransfer._instance;
	}

	public void javaToNative(Object object, TransferData transferData) {
		if (!checkMyType(object) || !isSupportedType(transferData))
			DND.error(DND.ERROR_INVALID_DATA);
		MyType[] myTypes = (MyType[]) object;
		try {
			// write data to a byte array and then ask super to convert to pMedium
			ByteArrayOutputStream out = new ByteArrayOutputStream();
			DataOutputStream writeOut = new DataOutputStream(out);
			for (int i = 0, length = myTypes.length; i < length; i++) {
				byte[] buffer = myTypes[i].firstName.getBytes();
				writeOut.writeInt(buffer.length);
				writeOut.write(buffer);
				buffer = myTypes[i].firstName.getBytes();
				writeOut.writeInt(buffer.length);
				writeOut.write(buffer);
			}
			byte[] buffer = out.toByteArray();
			writeOut.close();
			super.javaToNative(buffer, transferData);
		} catch (IOException e) {
		}
	}

	public Object nativeToJava(TransferData transferData) {
		if (isSupportedType(transferData)) {

			byte[] buffer = (byte[]) super.nativeToJava(transferData);
			if (buffer == null)
				return null;

			MyType[] myData = new MyType[0];
			try {
				ByteArrayInputStream in = new ByteArrayInputStream(buffer);
				DataInputStream readIn = new DataInputStream(in);
				while (readIn.available() > 20) {
					MyType datum = new MyType();
					int size = readIn.readInt();
					byte[] name = new byte[size];
					readIn.read(name);
					datum.firstName = new String(name);
					size = readIn.readInt();
					name = new byte[size];
					readIn.read(name);
					datum.lastName = new String(name);
					MyType[] newMyData = new MyType[myData.length + 1];
					System.arraycopy(myData, 0, newMyData, 0, myData.length);
					newMyData[myData.length] = datum;
					myData = newMyData;
				}
				readIn.close();
			} catch (IOException ex) {
				return null;
			}
			return myData;
		}

		return null;
	}

	protected int[] getTypeIds() {
		return new int[] { MyTypeTransfer.MYTYPEID };
	}

	protected String[] getTypeNames() {
		return new String[] { MyTypeTransfer.MYTYPENAME };
	}

	protected boolean validate(Object object) {
		return checkMyType(object);
	}

	boolean checkMyType(Object object) {
		if (object == null || !(object instanceof MyType[]) || ((MyType[]) object).length == 0)
			return false;
		MyType[] myTypes = (MyType[]) object;
		for (int i = 0; i < myTypes.length; i++)
			if (myTypes[i] == null || myTypes[i].firstName == null || myTypes[i].firstName.length() == 0
					|| myTypes[i].lastName == null || myTypes[i].lastName.length() == 0)
				return false;
		return true;
	}
}