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

 * Copyright (c) 2010 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.extension;

import org.eclipse.swt.internal.qt.UIThreadManager;

/**

 * A class that provides services for transferring the control over the

 * execution of the UI thread to the application, and services for obtaining

 * notifications of the state of the UI until the UI thread will return back to the

 * caller.

 * 

 * @see InternalUI

 * @see ApplicationUIListener

 */

public final class ApplicationUI {

	/**

	 * Hand over the execution of the UI thread to the application. If the

	 * application has not yet requested the UI thread then it will be waiting

	 * until that happens. The waiting can be aborted by calling

	 * <code>abortWait()</code>.

	 * 

	 * The control of the thread will be passed to the application. If the

	 * application allows the UI thread to return then this method will also

	 * return.

	 * 

	 * After calling this method and before the method has returned the state of

	 * the UI thread can be tracked by setting an

	 * <code>ApplicationUIListener</code>.

	 */

	public static void run() {

		UIThreadManager.runApplicationUI();

	}

	/**

	 * Aborts waiting the application to request the UI thread. This waiting can

	 * occur after <code>run()</code> has been called if the application has not

	 * yet at that point requested the UI thread and thus has not provided the

	 * Runnable to call back. Aborting the waiting will cause the UI thread to

	 * return from <code>run()</code>. If the application already obtained the

	 * control of the UI thread then this method does nothing. 

	 */

	public static void abortWait() {

		UIThreadManager.abortWait();

	}

	/**

	 * Sets the listener that will be notified of the state of the UI during its

	 * life-cycle under the application's control. 

	 * 

	 * @param listener The listener, or null to disable the notifications

	 */	

	public static void setListener(ApplicationUIListener listener) {

		final ApplicationUIListener applicationUIListener = listener;

		org.eclipse.swt.internal.qt.ApplicationUIListener internalListener; 

		if(listener != null) {

			internalListener = new org.eclipse.swt.internal.qt.ApplicationUIListener() {

				public void applicationUIThreadRequest() {

					applicationUIListener.applicationUIThreadRequest();

				}

			};

		} else {

			internalListener = null;

		}

		UIThreadManager.setApplicationUIListener(internalListener);

	}

}