org.eclipse.gmf.runtime.common.ui.action/src/org/eclipse/gmf/runtime/common/ui/action/actions/global/ClipboardContentsHelper.java

/******************************************************************************
 * Copyright (c) 2005 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.gmf.runtime.common.ui.action.actions.global;

import org.eclipse.swt.dnd.Clipboard;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.widgets.Display;

/**
 * This class is responsible for getting the contents from the clipboard.
 * 
 * @author cmahoney
 */
public class ClipboardContentsHelper {

	/**
	 * The singleton instance of <code>ClipboardContentsHelper</code>.
	 */
	private static ClipboardContentsHelper instance;

	/**
	 * Retrieves the singleton instance of <code>ClipboardContentsHelper</code>.
	 * 
	 * @return the singleton instance of <code>ClipboardContentsHelper</code>
	 */
	public static ClipboardContentsHelper getInstance() {
		if (instance == null) {
			instance = new ClipboardContentsHelper();
		}
		return instance;
	}

	/**
	 * Creates a new instance.
	 */
	protected ClipboardContentsHelper() {
		// nothing to initialize
	}

	/**
	 * Returns the system clipboard contents
	 * 
	 * @param dataType
	 *            The transfer agent
	 * @return Object Data associated with the transfer agent
	 */
	public Object getClipboardContents(Transfer dataType) {
		/* check the data type */
		assert null != dataType;

		/* create the clipboard instance */
		Clipboard clipboard = new Clipboard(Display.getCurrent());

		/* get the data from the clipboard */
		Object data = clipboard.getContents(dataType);

		/* free the system resources associated with the clipboard */
		clipboard.dispose();

		return data;
	}
}