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

  * Copyright (c) 2008 Cedric Chabanois 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:

  *     Cedric Chabanois - initial API and implementation

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

 package org.eclipse.swtbot.swt.finder.finders;

 import org.eclipse.swt.SWT;

 import org.eclipse.swt.widgets.Display;

 import org.eclipse.swt.widgets.Event;

 import org.eclipse.swt.widgets.Listener;

 import org.eclipse.swt.widgets.Menu;

 import org.eclipse.swt.widgets.Shell;

 import org.eclipse.swtbot.swt.finder.results.VoidResult;

 import org.eclipse.swtbot.swt.finder.utils.SWTUtils;

 import org.eclipse.swtbot.swt.finder.utils.internal.Assert;

 /**

  * Context menu finder that uses events to get the current context menu. It must be used instead of ContextMenuFinder

  * when the context menu is not associated with a Widget. It must be registered before the context menu appears.

  * <p>

  * Here is a sample usage:

  * </p>

  *

  * <pre>

  * EventContextMenuFinder eventContextMenuFinder = new EventContextMenuFinder();

  * try {

  *         eventContextMenuFinder.register();

  *         button.click(); // a popup menu appears below the button

  *         SWTBotMenu menu = new SWTBotMenu(new Finder(new ControlFinder(), eventContextMenuFinder), "Menu Text");

  *         menu.click();

  * } finally {

  *         eventContextMenuFinder.unregister();

  * }

  * </pre>

  *

  * This is not convenient to use but the need for this is not so frequent. In case you have better idea on the

  * implementation or usage please add a comment to <a href="http://swtbot.org/bugzilla/show_bug.cgi?id=19">this bug</a>.

  *

  * @author Cedric Chabanois <cchabanois [at] no-log [dot] org>

  * @version $Id$

  * @since 1.0

  */

 public class EventContextMenuFinder extends MenuFinder {

         /**

          * The current context menu.

          */

         private Menu                                        currentContextMenu        = null;

         /**

          * The listener to be used.

          */

         private final ShowHideListener        showHideListener;

         /**

          * The display to use.

          */

         private final Display                        display;

         /**

          * Creates an event based context menu finder.

          *

          * @param display the display

          * @throws NullPointerException Thrown if the display is <code>null</code>.

          */

         public EventContextMenuFinder(Display display) {

                 Assert.isNotNull(display, "The display can not be null"); //$NON-NLS-1$

                 this.display = display;

                 showHideListener = new ShowHideListener();

         }

         /**

          * Creates an event based context menu finder.

          */

         public EventContextMenuFinder() {

                 this(SWTUtils.display());

         }

         /**

          * Registers this finder so that it may start 'looking for' controls. It does so by listening for {@link SWT#Show}

          * and {@link SWT#Hide} events on menus.

          */

         public void register() {

                 UIThreadRunnable.syncExec(display, new VoidResult() {

                         public void run() {

                                 display.addFilter(SWT.Show, showHideListener);

                                 display.addFilter(SWT.Hide, showHideListener);

                         }

                 });

         }

         /**

          * Unregisters this finder so that it may stop 'looking for' controls. It does so by listening for {@link SWT#Show}

          * and {@link SWT#Hide} events on menus.

          */

         public void unregister() {

                 UIThreadRunnable.syncExec(display, new VoidResult() {

                         public void run() {

                                 display.removeFilter(SWT.Show, showHideListener);

                                 display.removeFilter(SWT.Hide, showHideListener);

                         }

                 });

         }

         /**

          * Gets the menu bar that has been found. This may be <code>null</code> if one had not been found yet.

          *

          * @see org.eclipse.swtbot.swt.finder.finders.MenuFinder#menuBar(org.eclipse.swt.widgets.Shell)

          * @param shell This is not used.

          * @return The menu or <code>null</code> if not yet found.

          */

         @Override

         protected Menu menuBar(final Shell shell) {

                 return currentContextMenu;

         }

         /**

          * A private class to listen for the show/hide events.

          */

         private class ShowHideListener implements Listener {

                 /**

                  * Handles the event by checking if it is the proper event. If it is a show, then the current context menu is

                  * set. Otherwise it will be set to <code>null</code> if it is a hide event.

                  *

                  * @see org.eclipse.swt.widgets.Listener#handleEvent(org.eclipse.swt.widgets.Event)

                  * @param event the event to check.

                  */

                 public void handleEvent(Event event) {

                         if (!(event.widget instanceof Menu))

                                 return;

                         Menu menu = (Menu) event.widget;

                         if (SWTUtils.hasStyle(menu, SWT.POP_UP)) {

                                 if (event.type == SWT.Show)

                                         currentContextMenu = menu;

                                 if (event.type == SWT.Hide)

                                         currentContextMenu = null;

                         }

                 }

         }

 }