Bug 38734 [Navigator] PasteAction should get clipboard contents only when needed
build 20030605 PasteAction.updateSelection checks whether there is a valid paste target after getting the clipboard contents. The paste target check does not involve the clipboard content and should therefore be done earlier, before reading the clipboard. The method also reads the FileTransfer data from the clipboard to check if the paste action should be enabled if there is no resource data. It does not actually use the file data. The new Clipboard.getAvailableTypes API should be used instead.
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/navigator/PasteAction.java
* All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.views.navigator;
import java.util.List;
import org.eclipse.core.resources.*;
import org.eclipse.jface.util.Assert;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.swt.dnd.Clipboard;
import org.eclipse.swt.dnd.FileTransfer;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.actions.*;
import org.eclipse.ui.help.WorkbenchHelp;
import org.eclipse.ui.part.ResourceTransfer;
/**
 * Standard action for pasting resources on the clipboard to the selected resource's location.
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 * 
 * @since 2.0
 */
 class PasteAction extends SelectionListenerAction {
	/**