bundles/org.eclipse.team.ui/src/org/eclipse/team/ui/synchronize/viewers/TreeViewerAdvisor.java - gerrit/platform/eclipse.platform.team - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2003 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.team.ui.synchronize.viewers;

 import org.eclipse.jface.action.IMenuManager;
 import org.eclipse.jface.action.Separator;
 import org.eclipse.jface.util.IPropertyChangeListener;
 import org.eclipse.jface.util.PropertyChangeEvent;
 import org.eclipse.jface.viewers.*;
 import org.eclipse.swt.widgets.*;
 import org.eclipse.team.core.TeamException;
 import org.eclipse.team.core.synchronize.SyncInfoTree;
 import org.eclipse.team.internal.ui.*;
 import org.eclipse.team.internal.ui.synchronize.CompressedFoldersModelProvider;
 import org.eclipse.team.internal.ui.synchronize.HierarchicalModelProvider;
 import org.eclipse.team.internal.ui.synchronize.actions.ExpandAllAction;
 import org.eclipse.ui.IWorkbenchActionConstants;
 import org.eclipse.ui.IWorkbenchPartSite;
 import org.eclipse.ui.internal.dialogs.ContainerCheckedTreeViewer;

 /**
  * A <code>TreeViewerAdvisor</code> that works with TreeViewers. Two default
  * tree viewers are provided that support navigation: <code>NavigableTreeViewer</code>
  * and <code>NavigableCheckboxTreeViewer</code>.
  * <p>
  * Note that this advisor can be used with any tree viewer. By default it provides an
  * expand all action, double click behavior on containers, and navigation support for
  * tree viewers.
  * </p><p>
  * By default this advisor supports hierarchical models and honour the compressed
  * folder Team preference for showing the sync set as compressed folders. Subclasses
  * can provide their own presentation models.
  * <p>
  * @since 3.0
  */
 public class TreeViewerAdvisor extends StructuredViewerAdvisor implements IPropertyChangeListener {

 	/**
 	 * Interface used to implement navigation for tree viewers. This interface is used by
 	 * {@link TreeViewerAdvisor#navigate(TreeViewer, boolean, boolean, boolean) to open
 	 * selections and navigate.
 	 */
 	public interface ITreeViewerAccessor {

 		public void createChildren(TreeItem item);
 		public void openSelection();
 	}

 	/**
 	 * A navigable checkboxec tree viewer that will work with the <code>navigate</code> method of
 	 * this advisor.
 	 */
 	public static class NavigableCheckboxTreeViewer extends ContainerCheckedTreeViewer implements ITreeViewerAccessor {
 		public NavigableCheckboxTreeViewer(Composite parent, int style) {
 			super(parent, style);
 		}

 		public void createChildren(TreeItem item) {
 			super.createChildren(item);
 		}

 		public void openSelection() {
 			fireOpen(new OpenEvent(this, getSelection()));
 		}
 	}

 	/**
 	 * A navigable tree viewer that will work with the <code>navigate</code> method of
 	 * this advisor.
 	 */
 	public static class NavigableTreeViewer extends TreeViewer implements ITreeViewerAccessor {
 		public NavigableTreeViewer(Composite parent, int style) {
 			super(parent, style);
 		}

 		public void createChildren(TreeItem item) {
 			super.createChildren(item);
 		}

 		public void openSelection() {
 			fireOpen(new OpenEvent(this, getSelection()));
 		}
 	}

 	private ExpandAllAction expandAllAction;

 	/**
 	 * Create an advisor that will allow viewer contributions with the given <code>targetID</code>. This
 	 * advisor will provide a presentation model based on the given sync info set. Note that it's important
 	 * to call {@link #dispose()} when finished with an advisor.
 	 *
 	 * @param targetID the targetID defined in the viewer contributions in a plugin.xml file.
 	 * @param site the workbench site with which to register the menuId. Can be <code>null</code> in which
 	 * case a site will be found using the default workbench page.
 	 * @param set the set of <code>SyncInfo</code> objects that are to be shown to the user.
 	 */
 	public TreeViewerAdvisor(String menuId, IWorkbenchPartSite site, SyncInfoTree set) {
 		super(menuId,site, set);
 		TeamUIPlugin.getPlugin().getPreferenceStore().addPropertyChangeListener(this);
 	}

 	/**
 	 * Create a tree viewer advisor that will provide a presentation model based on the given
 	 * sync info set. Note that it's important to call {@link #dispose()} when finished with
 	 * an advisor.
 	 *
 	 * @param set the set of <code>SyncInfo</code> objects that are to be shown to the user.
 	 */
 	public TreeViewerAdvisor(SyncInfoTree set) {
 		this(null, null, set);
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#dispose()
 	 */
 	public void dispose() {
 		TeamUIPlugin.getPlugin().getPreferenceStore().removePropertyChangeListener(this);
 		super.dispose();
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#navigate(boolean)
 	 */
 	public boolean navigate(boolean next) {
 		return TreeViewerAdvisor.navigate((TreeViewer)getViewer(), next, true, false);
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.jface.util.IPropertyChangeListener#propertyChange(org.eclipse.jface.util.PropertyChangeEvent)
 	 */
 	public void propertyChange(PropertyChangeEvent event) {
 		if (getViewer() != null && event.getProperty().equals(IPreferenceIds.SYNCVIEW_COMPRESS_FOLDERS)) {
 			try {
 				prepareInput(null);
 				setInput(getViewer());
 			} catch (TeamException e) {
 				TeamUIPlugin.log(e);
 			}
 		}
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#initializeViewer(org.eclipse.jface.viewers.StructuredViewer)
 	 */
 	public boolean validateViewer(StructuredViewer viewer) {
 		return viewer instanceof AbstractTreeViewer;
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#fillContextMenu(org.eclipse.jface.viewers.StructuredViewer, org.eclipse.jface.action.IMenuManager)
 	 */
 	protected void fillContextMenu(StructuredViewer viewer, IMenuManager manager) {
 		manager.add(expandAllAction);
 		manager.add(new Separator(IWorkbenchActionConstants.MB_ADDITIONS));
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#getDiffNodeController()
 	 */
 	protected ISynchronizeModelProvider getModelProvider() {
 		if(getShowCompressedFolders()) {
 			return new CompressedFoldersModelProvider((SyncInfoTree)getSyncInfoSet());
 		}
 		return new HierarchicalModelProvider((SyncInfoTree)getSyncInfoSet());
 	}

 	/**
 	 * Handles a double-click event from the viewer. Expands or collapses a folder when double-clicked.
 	 *
 	 * @param viewer the viewer
 	 * @param event the double-click event
 	 */
 	protected void handleDoubleClick(StructuredViewer viewer, DoubleClickEvent event) {
 		IStructuredSelection selection = (IStructuredSelection) event.getSelection();
 		Object element = selection.getFirstElement();
 		AbstractTreeViewer treeViewer = (AbstractTreeViewer) getViewer();
 		if (treeViewer.getExpandedState(element)) {
 			treeViewer.collapseToLevel(element, AbstractTreeViewer.ALL_LEVELS);
 		} else {
 			TreeViewerAdvisor.navigate((TreeViewer)getViewer(), true /* next */, false /* no-open */, true /* only-expand */);
 		}
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#initializeActions(org.eclipse.jface.viewers.StructuredViewer)
 	 */
 	protected void initializeActions(StructuredViewer viewer) {
 		super.initializeActions(viewer);
 		expandAllAction = new ExpandAllAction((AbstractTreeViewer) viewer);
 		Utils.initAction(expandAllAction, "action.expandAll."); //$NON-NLS-1$
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#initializeListeners(org.eclipse.jface.viewers.StructuredViewer)
 	 */
 	protected void initializeListeners(StructuredViewer viewer) {
 		viewer.addDoubleClickListener(new IDoubleClickListener() {
 			public void doubleClick(DoubleClickEvent event) {
 				handleDoubleClick(getViewer(), event);
 			}
 		});
 	}

 	/**
 	 * Return the state of the compressed folder setting.
 	 *
 	 * @return the state of the compressed folder setting.
 	 */
 	private boolean getShowCompressedFolders() {
 		return TeamUIPlugin.getPlugin().getPreferenceStore().getBoolean(IPreferenceIds.SYNCVIEW_COMPRESS_FOLDERS);
 	}

 	private static TreeItem findNextPrev(TreeViewer viewer, TreeItem item, boolean next) {
 		if (item == null || !(viewer instanceof ITreeViewerAccessor))
 			return null;
 		TreeItem children[] = null;
 		ITreeViewerAccessor treeAccessor = (ITreeViewerAccessor) viewer;
 		if (!next) {
 			TreeItem parent = item.getParentItem();
 			if (parent != null)
 				children = parent.getItems();
 			else
 				children = item.getParent().getItems();
 			if (children != null && children.length > 0) {
 				// goto previous child
 				int index = 0;
 				for (; index < children.length; index++)
 					if (children[index] == item)
 						break;
 				if (index > 0) {
 					item = children[index - 1];
 					while (true) {
 						treeAccessor.createChildren(item);
 						int n = item.getItemCount();
 						if (n <= 0)
 							break;
 						item.setExpanded(true);
 						item = item.getItems()[n - 1];
 					}
 					// previous
 					return item;
 				}
 			}
 			// go up
 			return parent;
 		} else {
 			item.setExpanded(true);
 			treeAccessor.createChildren(item);
 			if (item.getItemCount() > 0) {
 				// has children: go down
 				children = item.getItems();
 				return children[0];
 			}
 			while (item != null) {
 				children = null;
 				TreeItem parent = item.getParentItem();
 				if (parent != null)
 					children = parent.getItems();
 				else
 					children = item.getParent().getItems();
 				if (children != null && children.length > 0) {
 					// goto next child
 					int index = 0;
 					for (; index < children.length; index++)
 						if (children[index] == item)
 							break;
 					if (index < children.length - 1) {
 						// next
 						return children[index + 1];
 					}
 				}
 				// go up
 				item = parent;
 			}
 		}
 		return item;
 	}

 	private static void setSelection(TreeViewer viewer, TreeItem ti, boolean fireOpen, boolean expandOnly) {
 		if (ti != null) {
 			Object data= ti.getData();
 			if (data != null) {
 				// Fix for http://dev.eclipse.org/bugs/show_bug.cgi?id=20106
 				ISelection selection = new StructuredSelection(data);
 				if (expandOnly) {
 					viewer.expandToLevel(data, 0);
 				} else {
 					viewer.setSelection(selection, true);
 					ISelection currentSelection = viewer.getSelection();
 					if (fireOpen && currentSelection != null && selection.equals(currentSelection)) {
 						if (viewer instanceof ITreeViewerAccessor) {
 							((ITreeViewerAccessor) viewer).openSelection();
 						}
 					}
 				}
 			}
 		}
 	}

 	/**
 	 * Selects the next (or previous) node of the current selection.
 	 * If there is no current selection the first (last) node in the tree is selected.
 	 * Wraps around at end or beginning.
 	 * Clients may not override.
 	 *
 	 * @param next if <code>true</code> the next node is selected, otherwise the previous node
 	 * @return <code>true</code> if at end (or beginning)
 	 */
 	public static boolean navigate(TreeViewer viewer, boolean next, boolean fireOpen, boolean expandOnly) {
 		Tree tree = viewer.getTree();
 		if (tree == null)
 			return false;
 		TreeItem item = null;
 		TreeItem children[] = tree.getSelection();
 		if (children != null && children.length > 0)
 			item = children[0];
 		if (item == null) {
 			children = tree.getItems();
 			if (children != null && children.length > 0) {
 				item = children[0];
 				if (item != null && item.getItemCount() <= 0) {
 					setSelection(viewer, item, fireOpen, expandOnly); // Fix for http://dev.eclipse.org/bugs/show_bug.cgi?id=20106
 					return false;
 				}
 			}
 		}
 		while (true) {
 			item = findNextPrev(viewer, item, next);
 			if (item == null)
 				break;
 			if (item.getItemCount() <= 0)
 				break;
 		}
 		if (item != null) {
 			setSelection(viewer, item, fireOpen, expandOnly); // Fix for http://dev.eclipse.org/bugs/show_bug.cgi?id=20106
 			return false;
 		}
 		return true;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2003 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Common Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/cpl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.team.ui.synchronize.viewers;

	import org.eclipse.jface.action.IMenuManager;
	import org.eclipse.jface.action.Separator;
	import org.eclipse.jface.util.IPropertyChangeListener;
	import org.eclipse.jface.util.PropertyChangeEvent;
	import org.eclipse.jface.viewers.*;
	import org.eclipse.swt.widgets.*;
	import org.eclipse.team.core.TeamException;
	import org.eclipse.team.core.synchronize.SyncInfoTree;
	import org.eclipse.team.internal.ui.*;
	import org.eclipse.team.internal.ui.synchronize.CompressedFoldersModelProvider;
	import org.eclipse.team.internal.ui.synchronize.HierarchicalModelProvider;
	import org.eclipse.team.internal.ui.synchronize.actions.ExpandAllAction;
	import org.eclipse.ui.IWorkbenchActionConstants;
	import org.eclipse.ui.IWorkbenchPartSite;
	import org.eclipse.ui.internal.dialogs.ContainerCheckedTreeViewer;

	/**
	* A <code>TreeViewerAdvisor</code> that works with TreeViewers. Two default
	* tree viewers are provided that support navigation: <code>NavigableTreeViewer</code>
	* and <code>NavigableCheckboxTreeViewer</code>.
	* <p>
	* Note that this advisor can be used with any tree viewer. By default it provides an
	* expand all action, double click behavior on containers, and navigation support for
	* tree viewers.
	* </p><p>
	* By default this advisor supports hierarchical models and honour the compressed
	* folder Team preference for showing the sync set as compressed folders. Subclasses
	* can provide their own presentation models.
	* <p>
	* @since 3.0
	*/
	public class TreeViewerAdvisor extends StructuredViewerAdvisor implements IPropertyChangeListener {

	/**
	* Interface used to implement navigation for tree viewers. This interface is used by
	* {@link TreeViewerAdvisor#navigate(TreeViewer, boolean, boolean, boolean) to open
	* selections and navigate.
	*/
	public interface ITreeViewerAccessor {

	public void createChildren(TreeItem item);
	public void openSelection();
	}

	/**
	* A navigable checkboxec tree viewer that will work with the <code>navigate</code> method of
	* this advisor.
	*/
	public static class NavigableCheckboxTreeViewer extends ContainerCheckedTreeViewer implements ITreeViewerAccessor {
	public NavigableCheckboxTreeViewer(Composite parent, int style) {
	super(parent, style);
	}

	public void createChildren(TreeItem item) {
	super.createChildren(item);
	}

	public void openSelection() {
	fireOpen(new OpenEvent(this, getSelection()));
	}
	}

	/**
	* A navigable tree viewer that will work with the <code>navigate</code> method of
	* this advisor.
	*/
	public static class NavigableTreeViewer extends TreeViewer implements ITreeViewerAccessor {
	public NavigableTreeViewer(Composite parent, int style) {
	super(parent, style);
	}

	public void createChildren(TreeItem item) {
	super.createChildren(item);
	}

	public void openSelection() {
	fireOpen(new OpenEvent(this, getSelection()));
	}
	}

	private ExpandAllAction expandAllAction;

	/**
	* Create an advisor that will allow viewer contributions with the given <code>targetID</code>. This
	* advisor will provide a presentation model based on the given sync info set. Note that it's important
	* to call {@link #dispose()} when finished with an advisor.
	*
	* @param targetID the targetID defined in the viewer contributions in a plugin.xml file.
	* @param site the workbench site with which to register the menuId. Can be <code>null</code> in which
	* case a site will be found using the default workbench page.
	* @param set the set of <code>SyncInfo</code> objects that are to be shown to the user.
	*/
	public TreeViewerAdvisor(String menuId, IWorkbenchPartSite site, SyncInfoTree set) {
	super(menuId,site, set);
	TeamUIPlugin.getPlugin().getPreferenceStore().addPropertyChangeListener(this);
	}

	/**
	* Create a tree viewer advisor that will provide a presentation model based on the given
	* sync info set. Note that it's important to call {@link #dispose()} when finished with
	* an advisor.
	*
	* @param set the set of <code>SyncInfo</code> objects that are to be shown to the user.
	*/
	public TreeViewerAdvisor(SyncInfoTree set) {
	this(null, null, set);
	}

	/* (non-Javadoc)
	* @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#dispose()
	*/
	public void dispose() {
	TeamUIPlugin.getPlugin().getPreferenceStore().removePropertyChangeListener(this);
	super.dispose();
	}

	/* (non-Javadoc)
	* @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#navigate(boolean)
	*/
	public boolean navigate(boolean next) {
	return TreeViewerAdvisor.navigate((TreeViewer)getViewer(), next, true, false);
	}

	/* (non-Javadoc)
	* @see org.eclipse.jface.util.IPropertyChangeListener#propertyChange(org.eclipse.jface.util.PropertyChangeEvent)
	*/
	public void propertyChange(PropertyChangeEvent event) {
	if (getViewer() != null && event.getProperty().equals(IPreferenceIds.SYNCVIEW_COMPRESS_FOLDERS)) {
	try {
	prepareInput(null);
	setInput(getViewer());
	} catch (TeamException e) {
	TeamUIPlugin.log(e);
	}
	}
	}

	/* (non-Javadoc)
	* @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#initializeViewer(org.eclipse.jface.viewers.StructuredViewer)
	*/
	public boolean validateViewer(StructuredViewer viewer) {
	return viewer instanceof AbstractTreeViewer;
	}

	/* (non-Javadoc)
	* @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#fillContextMenu(org.eclipse.jface.viewers.StructuredViewer, org.eclipse.jface.action.IMenuManager)
	*/
	protected void fillContextMenu(StructuredViewer viewer, IMenuManager manager) {
	manager.add(expandAllAction);
	manager.add(new Separator(IWorkbenchActionConstants.MB_ADDITIONS));
	}

	/* (non-Javadoc)
	* @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#getDiffNodeController()
	*/
	protected ISynchronizeModelProvider getModelProvider() {
	if(getShowCompressedFolders()) {
	return new CompressedFoldersModelProvider((SyncInfoTree)getSyncInfoSet());
	}
	return new HierarchicalModelProvider((SyncInfoTree)getSyncInfoSet());
	}

	/**
	* Handles a double-click event from the viewer. Expands or collapses a folder when double-clicked.
	*
	* @param viewer the viewer
	* @param event the double-click event
	*/
	protected void handleDoubleClick(StructuredViewer viewer, DoubleClickEvent event) {
	IStructuredSelection selection = (IStructuredSelection) event.getSelection();
	Object element = selection.getFirstElement();
	AbstractTreeViewer treeViewer = (AbstractTreeViewer) getViewer();
	if (treeViewer.getExpandedState(element)) {
	treeViewer.collapseToLevel(element, AbstractTreeViewer.ALL_LEVELS);
	} else {
	TreeViewerAdvisor.navigate((TreeViewer)getViewer(), true /* next /, false / no-open /, true / only-expand */);
	}
	}

	/* (non-Javadoc)
	* @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#initializeActions(org.eclipse.jface.viewers.StructuredViewer)
	*/
	protected void initializeActions(StructuredViewer viewer) {
	super.initializeActions(viewer);
	expandAllAction = new ExpandAllAction((AbstractTreeViewer) viewer);
	Utils.initAction(expandAllAction, "action.expandAll."); //$NON-NLS-1$
	}

	/* (non-Javadoc)
	* @see org.eclipse.team.ui.synchronize.viewers.StructuredViewerAdvisor#initializeListeners(org.eclipse.jface.viewers.StructuredViewer)
	*/
	protected void initializeListeners(StructuredViewer viewer) {
	viewer.addDoubleClickListener(new IDoubleClickListener() {
	public void doubleClick(DoubleClickEvent event) {
	handleDoubleClick(getViewer(), event);
	}
	});
	}

	/**
	* Return the state of the compressed folder setting.
	*
	* @return the state of the compressed folder setting.
	*/
	private boolean getShowCompressedFolders() {
	return TeamUIPlugin.getPlugin().getPreferenceStore().getBoolean(IPreferenceIds.SYNCVIEW_COMPRESS_FOLDERS);
	}

	private static TreeItem findNextPrev(TreeViewer viewer, TreeItem item, boolean next) {
	if (item == null \|\| !(viewer instanceof ITreeViewerAccessor))
	return null;
	TreeItem children[] = null;
	ITreeViewerAccessor treeAccessor = (ITreeViewerAccessor) viewer;
	if (!next) {
	TreeItem parent = item.getParentItem();
	if (parent != null)
	children = parent.getItems();
	else
	children = item.getParent().getItems();
	if (children != null && children.length > 0) {
	// goto previous child
	int index = 0;
	for (; index < children.length; index++)
	if (children[index] == item)
	break;
	if (index > 0) {
	item = children[index - 1];
	while (true) {
	treeAccessor.createChildren(item);
	int n = item.getItemCount();
	if (n <= 0)
	break;
	item.setExpanded(true);
	item = item.getItems()[n - 1];
	}
	// previous
	return item;
	}
	}
	// go up
	return parent;
	} else {
	item.setExpanded(true);
	treeAccessor.createChildren(item);
	if (item.getItemCount() > 0) {
	// has children: go down
	children = item.getItems();
	return children[0];
	}
	while (item != null) {
	children = null;
	TreeItem parent = item.getParentItem();
	if (parent != null)
	children = parent.getItems();
	else
	children = item.getParent().getItems();
	if (children != null && children.length > 0) {
	// goto next child
	int index = 0;
	for (; index < children.length; index++)
	if (children[index] == item)
	break;
	if (index < children.length - 1) {
	// next
	return children[index + 1];
	}
	}
	// go up
	item = parent;
	}
	}
	return item;
	}

	private static void setSelection(TreeViewer viewer, TreeItem ti, boolean fireOpen, boolean expandOnly) {
	if (ti != null) {
	Object data= ti.getData();
	if (data != null) {
	// Fix for http://dev.eclipse.org/bugs/show_bug.cgi?id=20106
	ISelection selection = new StructuredSelection(data);
	if (expandOnly) {
	viewer.expandToLevel(data, 0);
	} else {
	viewer.setSelection(selection, true);
	ISelection currentSelection = viewer.getSelection();
	if (fireOpen && currentSelection != null && selection.equals(currentSelection)) {
	if (viewer instanceof ITreeViewerAccessor) {
	((ITreeViewerAccessor) viewer).openSelection();
	}
	}
	}
	}
	}
	}

	/**
	* Selects the next (or previous) node of the current selection.
	* If there is no current selection the first (last) node in the tree is selected.
	* Wraps around at end or beginning.
	* Clients may not override.
	*
	* @param next if <code>true</code> the next node is selected, otherwise the previous node
	* @return <code>true</code> if at end (or beginning)
	*/
	public static boolean navigate(TreeViewer viewer, boolean next, boolean fireOpen, boolean expandOnly) {
	Tree tree = viewer.getTree();
	if (tree == null)
	return false;
	TreeItem item = null;
	TreeItem children[] = tree.getSelection();
	if (children != null && children.length > 0)
	item = children[0];
	if (item == null) {
	children = tree.getItems();
	if (children != null && children.length > 0) {
	item = children[0];
	if (item != null && item.getItemCount() <= 0) {
	setSelection(viewer, item, fireOpen, expandOnly); // Fix for http://dev.eclipse.org/bugs/show_bug.cgi?id=20106
	return false;
	}
	}
	}
	while (true) {
	item = findNextPrev(viewer, item, next);
	if (item == null)
	break;
	if (item.getItemCount() <= 0)
	break;
	}
	if (item != null) {
	setSelection(viewer, item, fireOpen, expandOnly); // Fix for http://dev.eclipse.org/bugs/show_bug.cgi?id=20106
	return false;
	}
	return true;
	}
	}