/*******************************************************************************

 * Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).

 * 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:

 *     Nokia Corporation - initial implementation

 *******************************************************************************/

package org.eclipse.swt.internal.qt.graphics;

import org.eclipse.swt.widgets.Display;

import org.eclipse.swt.widgets.Internal_PackageSupport;

/** 

 * Class for general utilities for common graphics

 */

final class Utils {

	/**

	 * Validates that ui thread is created and execution is 

	 * currently in ui thread.

	 * 

	 * @throws java.lang.Error if ui thread is not initialized or 

	 * this method is not called within ui thread.

	 */

	static void validateUiThread() {

		if (!Config.ENABLE_UI_THREAD_VALIDATION) {

			return;

		}

		Display display = Internal_PackageSupport.getDisplayInstance();

		if(display == null) {

			display = Internal_PackageSupport.getInternalDisplayInstance();

		}

		if (display == null) {

			throw new Error("Ui thread not initialized or call was made outside ui thread");

		} else {

			if (Thread.currentThread() != display.getThread()) {

				throw new Error("Call to common graphics object occured outside ui thread");

			}

		}

	}

}