content: /*******************************************************************************
   * Copyright (c) 2000, 2008 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.wst.jsdt.internal.ui.refactoring.reorg;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.DataInputStream;
  import java.io.DataOutputStream;
  import java.io.IOException;
  
  import org.eclipse.core.runtime.Assert;
  import org.eclipse.swt.dnd.ByteArrayTransfer;
  import org.eclipse.swt.dnd.TransferData;
  import org.eclipse.wst.jsdt.internal.corext.refactoring.TypedSource;
  
  public class TypedSourceTransfer extends ByteArrayTransfer {
  
  	/**
  	 * Singleton instance.
  	 */
  	private static final TypedSourceTransfer fgInstance = new TypedSourceTransfer();
  	
  	// Create a unique ID to make sure that different Eclipse
  	// applications use different "types" of <code>TypedSourceTransfer</code>
  	private static final String TYPE_NAME = "typed-source-transfer-format:" + System.currentTimeMillis() + ":" + fgInstance.hashCode();//$NON-NLS-2$//$NON-NLS-1$
  	
  	private static final int TYPEID = registerType(TYPE_NAME);
  
  	private TypedSourceTransfer() {
  	}
  	
  	/**
  	 * Returns the singleton instance.
   	*
   	* @return the singleton instance
   	*/
  	public static TypedSourceTransfer getInstance() {
  		return fgInstance;
  	}
  
  	/* (non-Javadoc)
  	 * Method declared on Transfer.
  	 */
  	protected int[] getTypeIds() {
  		return new int[] {TYPEID};
  	}
  	
  	/* (non-Javadoc)
  	 * Returns the type names.
  	 *
  	 * @return the list of type names
  	 */
  	protected String[] getTypeNames() {
  		return new String[] {TYPE_NAME};
  	}
  
  	/* (non-Javadoc)
  	 * Method declared on Transfer.
  	 */
  	protected void javaToNative(Object data, TransferData transferData) {
  		if (! (data instanceof TypedSource[]))
  			return;
  		TypedSource[] sources = (TypedSource[]) data;	
  
  		/*
  		 * The serialization format is:
  		 *  (int) number of elements
  		 * Then, the following for each element:
  		 *  (int) type (see <code>IJavaScriptElement</code>)
  		 *  (String) source of the element
  		 */
  		
  		try {
  			ByteArrayOutputStream out = new ByteArrayOutputStream();
  			DataOutputStream dataOut = new DataOutputStream(out);
  
  			dataOut.writeInt(sources.length);
  
  			for (int i = 0; i < sources.length; i++) {
  				writeJavaElement(dataOut, sources[i]);
  			}
  
  			dataOut.close();
  			out.close();
  
  			super.javaToNative(out.toByteArray(), transferData);
  		} catch (IOException e) {
  			//it's best to send nothing if there were problems
  		}		
  	}
  
  	/* (non-Javadoc)
  	 * Method declared on Transfer.
  	 */
  	protected Object nativeToJava(TransferData transferData) {
  	
  		byte[] bytes = (byte[]) super.nativeToJava(transferData);
  		if (bytes == null)
  			return null;
  		DataInputStream in = new DataInputStream(new ByteArrayInputStream(bytes));
  		try {
  			int count = in.readInt();
  			TypedSource[] results = new TypedSource[count];
  			for (int i = 0; i < count; i++) {
  				results[i] = readJavaElement(in);
  				Assert.isNotNull(results[i]);
  			}
  			in.close();
  			return results;
  		} catch (IOException e) {
  			return null;
  		}
  	}
  
  	private static TypedSource readJavaElement(DataInputStream dataIn) throws IOException {
  		int type= dataIn.readInt();
  		String source= dataIn.readUTF();
  		return TypedSource.create(source, type);
  	}
  
  	private static void writeJavaElement(DataOutputStream dataOut, TypedSource sourceReference) throws IOException {
  		dataOut.writeInt(sourceReference.getType());
  		dataOut.writeUTF(sourceReference.getSource());
  	}
  }
  
  