plugins/org.eclipse.sphinx.emf.explorer/src/org/eclipse/sphinx/emf/explorer/sorters/NonFinalCommonViewerSorter.java

/*******************************************************************************
 * Copyright (c) 2006, 2012 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
 *     itemis - copied from org.eclipse.ui.navigator.CommonViewerSorter
 *              to create a non-final and thereby extensible equivalent of it;
 *              can be removed when bug
 *              https://bugs.eclipse.org/bugs/show_bug.cgi?id=478731
 *              has been resolved
 *******************************************************************************/
package org.eclipse.sphinx.emf.explorer.sorters;

import java.util.Set;

import org.eclipse.jface.viewers.TreePath;
import org.eclipse.jface.viewers.TreePathViewerSorter;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerSorter;
import org.eclipse.osgi.util.NLS;
import org.eclipse.ui.internal.navigator.CommonNavigatorMessages;
import org.eclipse.ui.internal.navigator.NavigatorContentService;
import org.eclipse.ui.internal.navigator.NavigatorContentServiceContentProvider;
import org.eclipse.ui.internal.navigator.NavigatorPlugin;
import org.eclipse.ui.navigator.INavigatorContentDescriptor;
import org.eclipse.ui.navigator.INavigatorContentService;
import org.eclipse.ui.navigator.INavigatorSorterService;
import org.eclipse.ui.navigator.Priority;

@SuppressWarnings("restriction")
public class NonFinalCommonViewerSorter extends TreePathViewerSorter {

	private static final int LEFT_UNDERSTANDS = 1;
	private static final int RIGHT_UNDERSTANDS = 2;
	private static final int BOTH_UNDERSTAND = LEFT_UNDERSTANDS | RIGHT_UNDERSTANDS;

	private INavigatorContentService contentService;

	private INavigatorSorterService sorterService;

	/**
	 * Create a sorter service attached to the given content service.
	 *
	 * @param aContentService
	 *            The content service used by the viewer that will use this sorter service.
	 * @since 3.3
	 */
	public void setContentService(INavigatorContentService aContentService) {
		contentService = aContentService;
		sorterService = contentService.getSorterService();
	}

	@Override
	public int category(Object element) {
		if (contentService == null) {
			return 0;
		}

		INavigatorContentDescriptor source = getSource(element);
		return source != null ? source.getSequenceNumber() : Priority.NORMAL_PRIORITY_VALUE;
	}

	private void logMissingExtension(Object parent, Object object) {
		NavigatorPlugin.logError(0, NLS.bind(CommonNavigatorMessages.CommonViewerSorter_NoContentExtensionForObject,
				object != null ? object.toString() : "<null>", parent != null ? parent.toString() : "<null>"), null); //$NON-NLS-1$ //$NON-NLS-2$
	}

	@Override
	public int compare(Viewer viewer, TreePath parentPath, Object e1, Object e2) {
		if (contentService == null) {
			return -1;
		}
		INavigatorContentDescriptor sourceOfLvalue = getSource(e1);
		INavigatorContentDescriptor sourceOfRvalue = getSource(e2);

		Object parent;
		if (parentPath == null) {
			parent = viewer.getInput();
		} else {
			parent = parentPath.getLastSegment();
		}

		if (sourceOfLvalue == null) {
			logMissingExtension(parent, e1);
			return -1;
		}
		if (sourceOfRvalue == null) {
			logMissingExtension(parent, e2);
			return -1;
		}

		ViewerSorter sorter = null;

		// shortcut if contributed by same source
		if (sourceOfLvalue == sourceOfRvalue) {
			sorter = sorterService.findSorter(sourceOfLvalue, parent, e1, e2);
		} else {

			boolean flags[] = new boolean[4];
			flags[0] = sourceOfLvalue.isTriggerPoint(e1);
			flags[1] = sourceOfLvalue.isTriggerPoint(e2);
			flags[2] = sourceOfRvalue.isTriggerPoint(e1);
			flags[3] = sourceOfRvalue.isTriggerPoint(e2);

			int whoknows = 0;
			whoknows = whoknows | (flags[0] & flags[1] ? LEFT_UNDERSTANDS : 0);
			whoknows = whoknows | (flags[2] & flags[3] ? RIGHT_UNDERSTANDS : 0);

			switch (whoknows) {
			case BOTH_UNDERSTAND:
				sorter = sourceOfLvalue.getSequenceNumber() < sourceOfRvalue.getSequenceNumber()
						? sorterService.findSorter(sourceOfLvalue, parent, e1, e2) : sorterService.findSorter(sourceOfRvalue, parent, e1, e2);
				break;
			case LEFT_UNDERSTANDS:
				sorter = sorterService.findSorter(sourceOfLvalue, parent, e1, e2);
				break;
			case RIGHT_UNDERSTANDS:
				sorter = sorterService.findSorter(sourceOfRvalue, parent, e1, e2);
				break;
			}
		}

		if (sorter != null) {
			return sorter.compare(viewer, e1, e2);
		}

		int categoryDelta = category(e1) - category(e2);
		if (categoryDelta == 0) {
			return super.compare(viewer, e1, e2);
		}
		return categoryDelta;
	}

	@Override
	public boolean isSorterProperty(Object element, String property) {
		// Have to get the parent path from the content provider
		NavigatorContentServiceContentProvider cp = (NavigatorContentServiceContentProvider) contentService.createCommonContentProvider();
		TreePath[] parentPaths = cp.getParents(element);
		for (TreePath parentPath : parentPaths) {
			if (isSorterProperty(parentPath, element, property)) {
				return true;
			}
		}
		return false;
	}

	@Override
	public boolean isSorterProperty(TreePath parentPath, Object element, String property) {
		INavigatorContentDescriptor contentDesc = getSource(element);
		if (parentPath.getSegmentCount() == 0) {
			return false;
		}
		ViewerSorter sorter = sorterService.findSorter(contentDesc, parentPath.getLastSegment(), element, null);
		if (sorter != null) {
			return sorter.isSorterProperty(element, property);
		}
		return false;
	}

	private INavigatorContentDescriptor getSource(Object o) {
		// Fast path - just an optimization for the common case
		INavigatorContentDescriptor ncd = ((NavigatorContentService) contentService).getSourceOfContribution(o);
		if (ncd != null) {
			return ncd;
		}

		Set<?> descriptors = ((NavigatorContentService) contentService).findDescriptorsByTriggerPoint(o, NavigatorContentService.CONSIDER_OVERRIDES);
		if (descriptors != null && descriptors.size() > 0) {
			ncd = (INavigatorContentDescriptor) descriptors.iterator().next();
			return ncd;
		}
		return null;
	}
}