org.eclipse.mylyn.reviews.r4e.ui/src/org/eclipse/mylyn/reviews/r4e/ui/internal/commands/filters/GoIntoFilterHandler.java

/*******************************************************************************
 * Copyright (c) 2011, 2012 Ericsson AB 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
 * 
 * Description:
 * 
 * This class implements the navigator view toolbar command set/unset the tree viewer input to
 * the currently selected element
 * 
 * Contributors:
 *   Sebastien Dubois - Created for Mylyn Review R4E project
 *   
 ******************************************************************************/
package org.eclipse.mylyn.reviews.r4e.ui.internal.commands.filters;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.mylyn.reviews.r4e.ui.R4EUIPlugin;
import org.eclipse.mylyn.reviews.r4e.ui.internal.filters.FocusFilter;
import org.eclipse.mylyn.reviews.r4e.ui.internal.model.IR4EUIModelElement;
import org.eclipse.mylyn.reviews.r4e.ui.internal.model.R4EUIModelController;
import org.eclipse.mylyn.reviews.r4e.ui.internal.navigator.ReviewNavigatorActionGroup;
import org.eclipse.mylyn.reviews.r4e.ui.internal.navigator.ReviewNavigatorTreeViewer;
import org.eclipse.ui.handlers.HandlerUtil;
import org.eclipse.ui.progress.UIJob;

/**
 * @author Sebastien Dubois
 * @version $Revision: 1.0 $
 */
public class GoIntoFilterHandler extends AbstractHandler {

	// ------------------------------------------------------------------------
	// Constants
	// ------------------------------------------------------------------------

	/**
	 * Field COMMAND_MESSAGE. (value is ""Changing focus..."")
	 */
	private static final String COMMAND_MESSAGE = "Changing focus...";

	// ------------------------------------------------------------------------
	// Methods
	// ------------------------------------------------------------------------

	/**
	 * Method execute.
	 * 
	 * @param aEvent
	 *            ExecutionEvent
	 * @return Object
	 * @see org.eclipse.core.commands.IHandler#execute(ExecutionEvent)
	 */
	public Object execute(final ExecutionEvent aEvent) {

		final UIJob job = new UIJob(COMMAND_MESSAGE) {
			@Override
			public IStatus runInUIThread(IProgressMonitor monitor) {
				monitor.beginTask(COMMAND_MESSAGE, 1);

				//We need to preserve the expansion state and restore it afterwards
				final ReviewNavigatorTreeViewer viewer = (ReviewNavigatorTreeViewer) R4EUIModelController.getNavigatorView()
						.getTreeViewer();

				//Verify is the viewer is disposed
				if (!viewer.getControl().isDisposed()) {
					final Object[] elements = viewer.getVisibleExpandedElements();
					final FocusFilter filter = ((ReviewNavigatorActionGroup) R4EUIModelController.getNavigatorView()
							.getActionSet()).getFocusFilter();

					boolean oldValue;
					try {
						oldValue = HandlerUtil.toggleCommandState(aEvent.getCommand());
					} catch (ExecutionException e) {
						monitor.done();
						return Status.CANCEL_STATUS;
					}

					if (!oldValue) {
						//Set current element as root level for the navigator tree
						final IStructuredSelection selection = (IStructuredSelection) viewer.getSelection();
						if (null != selection) {
							final IR4EUIModelElement element = (IR4EUIModelElement) selection.getFirstElement();
							if (null != element) {
								R4EUIPlugin.Ftracer.traceInfo("Setting focus on current element"); //$NON-NLS-1$
								R4EUIModelController.setCurrentFocusElement(element);
								viewer.setInput(element.getParent());
								viewer.setDefaultInput(element.getParent());
								viewer.addFilter(filter);
								viewer.setExpandedElements(elements);
							}
						}
					} else {
						//Set Root element as root level for the navigator tree
						R4EUIPlugin.Ftracer.traceInfo("Removing focus on current element"); //$NON-NLS-1$
						viewer.removeFilter(filter);
						R4EUIModelController.setCurrentFocusElement(R4EUIModelController.getRootElement());
						if (R4EUIModelController.getNavigatorView().isDefaultDisplay()) {
							viewer.setInput(R4EUIModelController.getRootElement());
						} else { //Assume TreeTable display
							viewer.setInput(R4EUIModelController.getActiveReview());
							viewer.setDefaultInput(R4EUIModelController.getRootElement());
						}
						if (0 < elements.length) {
							for (Object element : elements) {
								viewer.expandToLevel((element), 1);
							}
						}
					}
				}

				monitor.worked(1);
				monitor.done();
				return Status.OK_STATUS;
			}
		};
		job.setUser(true);
		job.schedule();
		return null;
	}
}