org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/viewers/model/TreeModelLabelProvider.java - gerrit/platform/eclipse.platform.debug - Git at Google

 /*******************************************************************************
  * Copyright (c) 2006, 2009 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
  *     Wind River - Pawel Piech - Added coalescing of label updates (bug 247575).
  *     Pawel Piech (Wind River) - added support for a virtual tree model viewer (Bug 242489)
  *******************************************************************************/
 package org.eclipse.debug.internal.ui.viewers.model;

 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;

 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.ISafeRunnable;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.ListenerList;
 import org.eclipse.core.runtime.SafeRunner;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.debug.internal.ui.DebugUIPlugin;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IElementLabelProvider;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.ILabelUpdate;
 import org.eclipse.debug.internal.ui.viewers.model.provisional.IPresentationContext;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.jface.viewers.ColumnLabelProvider;
 import org.eclipse.jface.viewers.TreePath;
 import org.eclipse.jface.viewers.ViewerCell;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.FontData;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.RGB;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.ui.progress.UIJob;

 /**
  * @since 3.3
  */
 public class TreeModelLabelProvider extends ColumnLabelProvider implements ITreeModelLabelProvider {

 	private ITreeModelLabelProviderTarget fViewer;
 	private List fComplete;

 	/**
 	 * Cache of images used for elements in this label provider. Label updates
 	 * use the method <code>getImage(...)</code> to cache images for
 	 * image descriptors. The images are disposed with this label provider.
 	 */
 	private Map fImageCache = new HashMap();

 	/**
 	 * Cache of the fonts used for elements in this label provider. Label updates
 	 * use the method <code>getFont(...)</code> to cache fonts for
 	 * FontData objects. The fonts are disposed with this label provider.
 	 */
 	private Map fFontCache = new HashMap();

 	/**
 	 * Cache of the colors used for elements in this label provider. Label updates
 	 * use the method <code>getColor(...)</code> to cache colors for
 	 * RGB values. The colors are disposed with this label provider.
 	 */
 	private Map fColorCache = new HashMap();

 	/**
 	 * Label listeners
 	 */
 	private ListenerList fLabelListeners = new ListenerList();

 	/**
 	 * Updates waiting to be sent to the label provider.  The map contains
 	 * lists of updates, keyed using the provider.
      * <p>
      * Note: this variable should only be accessed inside a synchronized section
      * using the enclosing label provider instance.
      * </p>
 	 */
 	private Map fPendingUpdates = new HashMap();

 	/**
 	 * A job that will send the label update requests.
 	 * This variable allows the job to be canceled and re-scheduled if
 	 * new updates are requested.
 	 * <p>
 	 * Note: this variable should only be accessed inside a synchronized section
 	 * using the enclosing label provider instance.
 	 * </p>
 	 */
 	private UIJob fPendingUpdatesJob;

 	/**
 	 * List of updates in progress
 	 */
 	private List fUpdatesInProgress = new ArrayList();

 	/**
 	 * Constructs a new label provider on the given display
 	 */
 	public TreeModelLabelProvider(ITreeModelLabelProviderTarget viewer) {
 		fViewer = viewer;
 	}

 	/**
 	 * Returns an image for the given image descriptor or <code>null</code>. Adds the image
 	 * to a cache of images if it does not already exist.
 	 *
 	 * @param descriptor image descriptor or <code>null</code>
 	 * @return image or <code>null</code>
 	 */
 	public Image getImage(ImageDescriptor descriptor) {
 		if (descriptor == null) {
 			return null;
 		}
 		Image image = (Image) fImageCache.get(descriptor);
 		if (image == null) {
 			image = new Image(getDisplay(), descriptor.getImageData());
 			fImageCache.put(descriptor, image);
 		}
 		return image;
 	}

 	/**
 	 * Returns the display to use for resource allocation.
 	 *
 	 * @return display
 	 */
 	private Display getDisplay() {
 		return fViewer.getDisplay();
 	}

 	/**
 	 * Returns a font for the given font data or <code>null</code>. Adds the font to the font
 	 * cache if not yet created.
 	 *
 	 * @param fontData font data or <code>null</code>
 	 * @return font font or <code>null</code>
 	 */
 	public Font getFont(FontData fontData) {
 		if (fontData == null) {
 			return null;
 		}
 		Font font = (Font) fFontCache.get(fontData);
 		if (font == null) {
 			font = new Font(getDisplay(), fontData);
 			fFontCache.put(fontData, font);
 		}
 		return font;
 	}

 	/**
 	 * Returns a color for the given RGB or <code>null</code>. Adds the color to the color
 	 * cache if not yet created.
 	 *
 	 * @param rgb RGB or <code>null</code>
 	 * @return color or <code>null</code>
 	 */
 	public Color getColor(RGB rgb) {
 		if (rgb == null) {
 			return null;
 		}
 		Color color = (Color) fColorCache.get(rgb);
 		if (color == null) {
 			color = new Color(getDisplay(), rgb);
 			fColorCache.put(rgb, color);
 		}
 		return color;
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.jface.viewers.BaseLabelProvider#dispose()
 	 */
 	public void dispose() {
 		synchronized (fUpdatesInProgress) {
 			Iterator updatesInProgress = fUpdatesInProgress.iterator();
 			while (updatesInProgress.hasNext()) {
 				ILabelUpdate currentUpdate = (ILabelUpdate) updatesInProgress.next();
 				currentUpdate.cancel();
 			}
 		}
 		synchronized (this) {
 			if (fPendingUpdatesJob != null) {
 				fPendingUpdatesJob.cancel();
 				fPendingUpdatesJob = null;
 			}
 		}
 		Iterator images = fImageCache.values().iterator();
 		while (images.hasNext()) {
 			Image image = (Image) images.next();
 			image.dispose();
 		}
 		fImageCache.clear();

 		Iterator fonts = fFontCache.values().iterator();
 		while (fonts.hasNext()) {
 			Font font = (Font) fonts.next();
 			font.dispose();
 		}
 		fFontCache.clear();

 		Iterator colors = fColorCache.values().iterator();
 		while (colors.hasNext()) {
 			Color color = (Color) colors.next();
 			color.dispose();
 		}
 		fColorCache.clear();

 		super.dispose();
 	}

 	public synchronized void update(ViewerCell cell) {
 		// NOT USED - the viewer updates each row instead
 	}

 	public synchronized boolean update(TreePath elementPath) {
 		String[] visibleColumns = fViewer.getVisibleColumns();
 		Object element = elementPath.getLastSegment();
 		IElementLabelProvider presentation = ViewerAdapterService.getLabelProvider(element);
 		if (presentation != null) {
 		    List updates = (List)fPendingUpdates.get(presentation);
 		    if (updates == null) {
 		        updates = new LinkedList();
 		        fPendingUpdates.put(presentation, updates);
 		    }
 		    updates.add(new LabelUpdate(fViewer.getInput(), elementPath, this, fViewer, visibleColumns, fViewer.getPresentationContext()));
 		    if (fPendingUpdatesJob != null) {
 		    	fPendingUpdatesJob.cancel();
 		    }
 		    fPendingUpdatesJob = new UIJob(fViewer.getDisplay(), "Schedule Pending Label Updates") { //$NON-NLS-1$
 				public IStatus runInUIThread(IProgressMonitor monitor) {
 					 startRequests(this);
 					 return Status.OK_STATUS;
 				}
 			};
 			fPendingUpdatesJob.setSystem(true);
 			fPendingUpdatesJob.schedule();
 			return true;
 		} else {
 		    return false;
 		}
 	}

 	private void startRequests(UIJob updateJob) {
 	    // Avoid calling providers inside a synchronized section.  Instead
 	    // copy the updates map into a new variable.
 	    Map updates = null;
 	    synchronized(this) {
 	        if (updateJob == fPendingUpdatesJob) {
     	        updates = fPendingUpdates;
     	        fPendingUpdates = new HashMap();
     	        fPendingUpdatesJob = null;
 	        }
 	    }

 	    if (updates != null) {
             for (Iterator itr = updates.keySet().iterator(); itr.hasNext();) {
                 IElementLabelProvider presentation = (IElementLabelProvider)itr.next();
                 List list = (List)updates.get(presentation);
                 for (Iterator listItr = list.iterator(); listItr.hasNext();) {
                     updateStarted((ILabelUpdate)listItr.next());
                 }
                 presentation.update( (ILabelUpdate[])list.toArray(new ILabelUpdate[list.size()]) );
             }
 	    }
 	}

 	/**
 	 * Returns the presentation context for this label provider.
 	 *
 	 * @return presentation context
 	 */
 	protected IPresentationContext getPresentationContext() {
 		return fViewer.getPresentationContext();
 	}

     /**
      * A label update is complete.
      *
      * @param update
      */
     protected synchronized void complete(ILabelUpdate update) {
 		if (update.isCanceled()){
 			updateComplete(update);
 		} else {
 			if (fComplete == null) {
 				fComplete = new ArrayList();
 				UIJob job = new UIJob(getDisplay(), "Label Updates") { //$NON-NLS-1$
 					public IStatus runInUIThread(IProgressMonitor monitor) {
 						LabelUpdate[] updates = null;
 						synchronized (TreeModelLabelProvider.this) {
 							updates = (LabelUpdate[]) fComplete.toArray(new LabelUpdate[fComplete.size()]);
 							fComplete = null;
 						}
 						//System.out.println("Changed Labels: " + updates.length);
 						for (int i = 0; i < updates.length; i++) {
 							updates[i].update();
 						}
 						return Status.OK_STATUS;
 					}
 				};
 				job.setSystem(true);
 				job.schedule(10L);
 			}
 			fComplete.add(update);
 		}
     }

 	public void addLabelUpdateListener(ILabelUpdateListener listener) {
 		fLabelListeners.add(listener);
 	}

 	public void removeLabelUpdateListener(ILabelUpdateListener listener) {
 		fLabelListeners.remove(listener);
 	}

 	/**
 	 * Notification an update request has started
 	 *
 	 * @param update
 	 */
 	void updateStarted(ILabelUpdate update) {
 		boolean begin = false;
 		synchronized (fUpdatesInProgress) {
 			begin = fUpdatesInProgress.isEmpty();
 			fUpdatesInProgress.add(update);
 		}
 		if (begin) {
 			if (ModelContentProvider.DEBUG_UPDATE_SEQUENCE && (ModelContentProvider.DEBUG_PRESENTATION_ID == null || ModelContentProvider.DEBUG_PRESENTATION_ID.equals(getPresentationContext().getId()))) {
 				System.out.println("LABEL SEQUENCE BEGINS"); //$NON-NLS-1$
 			}
 			notifyUpdate(ModelContentProvider.UPDATE_SEQUENCE_BEGINS, null);
 		}
 		if (ModelContentProvider.DEBUG_UPDATE_SEQUENCE && (ModelContentProvider.DEBUG_PRESENTATION_ID == null || ModelContentProvider.DEBUG_PRESENTATION_ID.equals(getPresentationContext().getId()))) {
 			System.out.println("\tBEGIN - " + update); //$NON-NLS-1$
 		}
 		notifyUpdate(ModelContentProvider.UPDATE_BEGINS, update);
 	}

 	/**
 	 * Notification an update request has completed
 	 *
 	 * @param update
 	 */
 	void updateComplete(ILabelUpdate update) {
 		boolean end = false;
 		synchronized (fUpdatesInProgress) {
 			fUpdatesInProgress.remove(update);
 			end = fUpdatesInProgress.isEmpty();
 		}
 		if (ModelContentProvider.DEBUG_UPDATE_SEQUENCE && (ModelContentProvider.DEBUG_PRESENTATION_ID == null || ModelContentProvider.DEBUG_PRESENTATION_ID.equals(getPresentationContext().getId()))) {
 			System.out.println("\tEND - " + update); //$NON-NLS-1$
 		}
 		notifyUpdate(ModelContentProvider.UPDATE_COMPLETE, update);
 		if (end) {
 			if (ModelContentProvider.DEBUG_UPDATE_SEQUENCE && (ModelContentProvider.DEBUG_PRESENTATION_ID == null || ModelContentProvider.DEBUG_PRESENTATION_ID.equals(getPresentationContext().getId()))) {
 				System.out.println("LABEL SEQUENCE ENDS"); //$NON-NLS-1$
 			}
 			notifyUpdate(ModelContentProvider.UPDATE_SEQUENCE_COMPLETE, null);
 		}
 	}

 	protected void notifyUpdate(final int type, final ILabelUpdate update) {
 		if (!fLabelListeners.isEmpty()) {
 			Object[] listeners = fLabelListeners.getListeners();
 			for (int i = 0; i < listeners.length; i++) {
 				final ILabelUpdateListener listener = (ILabelUpdateListener) listeners[i];
 				SafeRunner.run(new ISafeRunnable() {
 					public void run() throws Exception {
 						switch (type) {
 							case ModelContentProvider.UPDATE_SEQUENCE_BEGINS:
 								listener.labelUpdatesBegin();
 								break;
 							case ModelContentProvider.UPDATE_SEQUENCE_COMPLETE:
 								listener.labelUpdatesComplete();
 								break;
 							case ModelContentProvider.UPDATE_BEGINS:
 								listener.labelUpdateStarted(update);
 								break;
 							case ModelContentProvider.UPDATE_COMPLETE:
 								listener.labelUpdateComplete(update);
 								break;
 						}
 					}
 					public void handleException(Throwable exception) {
 						DebugUIPlugin.log(exception);
 					}
 				});
 			}
 		}
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2006, 2009 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
	* Wind River - Pawel Piech - Added coalescing of label updates (bug 247575).
	* Pawel Piech (Wind River) - added support for a virtual tree model viewer (Bug 242489)
	*******************************************************************************/
	package org.eclipse.debug.internal.ui.viewers.model;

	import java.util.ArrayList;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.LinkedList;
	import java.util.List;
	import java.util.Map;

	import org.eclipse.core.runtime.IProgressMonitor;
	import org.eclipse.core.runtime.ISafeRunnable;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.ListenerList;
	import org.eclipse.core.runtime.SafeRunner;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.debug.internal.ui.DebugUIPlugin;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.IElementLabelProvider;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.ILabelUpdate;
	import org.eclipse.debug.internal.ui.viewers.model.provisional.IPresentationContext;
	import org.eclipse.jface.resource.ImageDescriptor;
	import org.eclipse.jface.viewers.ColumnLabelProvider;
	import org.eclipse.jface.viewers.TreePath;
	import org.eclipse.jface.viewers.ViewerCell;
	import org.eclipse.swt.graphics.Color;
	import org.eclipse.swt.graphics.Font;
	import org.eclipse.swt.graphics.FontData;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.graphics.RGB;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.ui.progress.UIJob;

	/**
	* @since 3.3
	*/
	public class TreeModelLabelProvider extends ColumnLabelProvider implements ITreeModelLabelProvider {

	private ITreeModelLabelProviderTarget fViewer;
	private List fComplete;

	/**
	* Cache of images used for elements in this label provider. Label updates
	* use the method <code>getImage(...)</code> to cache images for
	* image descriptors. The images are disposed with this label provider.
	*/
	private Map fImageCache = new HashMap();

	/**
	* Cache of the fonts used for elements in this label provider. Label updates
	* use the method <code>getFont(...)</code> to cache fonts for
	* FontData objects. The fonts are disposed with this label provider.
	*/
	private Map fFontCache = new HashMap();

	/**
	* Cache of the colors used for elements in this label provider. Label updates
	* use the method <code>getColor(...)</code> to cache colors for
	* RGB values. The colors are disposed with this label provider.
	*/
	private Map fColorCache = new HashMap();

	/**
	* Label listeners
	*/
	private ListenerList fLabelListeners = new ListenerList();

	/**
	* Updates waiting to be sent to the label provider. The map contains
	* lists of updates, keyed using the provider.
	* <p>
	* Note: this variable should only be accessed inside a synchronized section
	* using the enclosing label provider instance.
	* </p>
	*/
	private Map fPendingUpdates = new HashMap();

	/**
	* A job that will send the label update requests.
	* This variable allows the job to be canceled and re-scheduled if
	* new updates are requested.
	* <p>
	* Note: this variable should only be accessed inside a synchronized section
	* using the enclosing label provider instance.
	* </p>
	*/
	private UIJob fPendingUpdatesJob;

	/**
	* List of updates in progress
	*/
	private List fUpdatesInProgress = new ArrayList();

	/**
	* Constructs a new label provider on the given display
	*/
	public TreeModelLabelProvider(ITreeModelLabelProviderTarget viewer) {
	fViewer = viewer;
	}

	/**
	* Returns an image for the given image descriptor or <code>null</code>. Adds the image
	* to a cache of images if it does not already exist.
	*
	* @param descriptor image descriptor or <code>null</code>
	* @return image or <code>null</code>
	*/
	public Image getImage(ImageDescriptor descriptor) {
	if (descriptor == null) {
	return null;
	}
	Image image = (Image) fImageCache.get(descriptor);
	if (image == null) {
	image = new Image(getDisplay(), descriptor.getImageData());
	fImageCache.put(descriptor, image);
	}
	return image;
	}

	/**
	* Returns the display to use for resource allocation.
	*
	* @return display
	*/
	private Display getDisplay() {
	return fViewer.getDisplay();
	}

	/**
	* Returns a font for the given font data or <code>null</code>. Adds the font to the font
	* cache if not yet created.
	*
	* @param fontData font data or <code>null</code>
	* @return font font or <code>null</code>
	*/
	public Font getFont(FontData fontData) {
	if (fontData == null) {
	return null;
	}
	Font font = (Font) fFontCache.get(fontData);
	if (font == null) {
	font = new Font(getDisplay(), fontData);
	fFontCache.put(fontData, font);
	}
	return font;
	}

	/**
	* Returns a color for the given RGB or <code>null</code>. Adds the color to the color
	* cache if not yet created.
	*
	* @param rgb RGB or <code>null</code>
	* @return color or <code>null</code>
	*/
	public Color getColor(RGB rgb) {
	if (rgb == null) {
	return null;
	}
	Color color = (Color) fColorCache.get(rgb);
	if (color == null) {
	color = new Color(getDisplay(), rgb);
	fColorCache.put(rgb, color);
	}
	return color;
	}

	/* (non-Javadoc)
	* @see org.eclipse.jface.viewers.BaseLabelProvider#dispose()
	*/
	public void dispose() {
	synchronized (fUpdatesInProgress) {
	Iterator updatesInProgress = fUpdatesInProgress.iterator();
	while (updatesInProgress.hasNext()) {
	ILabelUpdate currentUpdate = (ILabelUpdate) updatesInProgress.next();
	currentUpdate.cancel();
	}
	}
	synchronized (this) {
	if (fPendingUpdatesJob != null) {
	fPendingUpdatesJob.cancel();
	fPendingUpdatesJob = null;
	}
	}
	Iterator images = fImageCache.values().iterator();
	while (images.hasNext()) {
	Image image = (Image) images.next();
	image.dispose();
	}
	fImageCache.clear();

	Iterator fonts = fFontCache.values().iterator();
	while (fonts.hasNext()) {
	Font font = (Font) fonts.next();
	font.dispose();
	}
	fFontCache.clear();

	Iterator colors = fColorCache.values().iterator();
	while (colors.hasNext()) {
	Color color = (Color) colors.next();
	color.dispose();
	}
	fColorCache.clear();

	super.dispose();
	}

	public synchronized void update(ViewerCell cell) {
	// NOT USED - the viewer updates each row instead
	}

	public synchronized boolean update(TreePath elementPath) {
	String[] visibleColumns = fViewer.getVisibleColumns();
	Object element = elementPath.getLastSegment();
	IElementLabelProvider presentation = ViewerAdapterService.getLabelProvider(element);
	if (presentation != null) {
	List updates = (List)fPendingUpdates.get(presentation);
	if (updates == null) {
	updates = new LinkedList();
	fPendingUpdates.put(presentation, updates);
	}
	updates.add(new LabelUpdate(fViewer.getInput(), elementPath, this, fViewer, visibleColumns, fViewer.getPresentationContext()));
	if (fPendingUpdatesJob != null) {
	fPendingUpdatesJob.cancel();
	}
	fPendingUpdatesJob = new UIJob(fViewer.getDisplay(), "Schedule Pending Label Updates") { //$NON-NLS-1$
	public IStatus runInUIThread(IProgressMonitor monitor) {
	startRequests(this);
	return Status.OK_STATUS;
	}
	};
	fPendingUpdatesJob.setSystem(true);
	fPendingUpdatesJob.schedule();
	return true;
	} else {
	return false;
	}
	}

	private void startRequests(UIJob updateJob) {
	// Avoid calling providers inside a synchronized section. Instead
	// copy the updates map into a new variable.
	Map updates = null;
	synchronized(this) {
	if (updateJob == fPendingUpdatesJob) {
	updates = fPendingUpdates;
	fPendingUpdates = new HashMap();
	fPendingUpdatesJob = null;
	}
	}

	if (updates != null) {
	for (Iterator itr = updates.keySet().iterator(); itr.hasNext();) {
	IElementLabelProvider presentation = (IElementLabelProvider)itr.next();
	List list = (List)updates.get(presentation);
	for (Iterator listItr = list.iterator(); listItr.hasNext();) {
	updateStarted((ILabelUpdate)listItr.next());
	}
	presentation.update( (ILabelUpdate[])list.toArray(new ILabelUpdate[list.size()]) );
	}
	}
	}

	/**
	* Returns the presentation context for this label provider.
	*
	* @return presentation context
	*/
	protected IPresentationContext getPresentationContext() {
	return fViewer.getPresentationContext();
	}

	/**
	* A label update is complete.
	*
	* @param update
	*/
	protected synchronized void complete(ILabelUpdate update) {
	if (update.isCanceled()){
	updateComplete(update);
	} else {
	if (fComplete == null) {
	fComplete = new ArrayList();
	UIJob job = new UIJob(getDisplay(), "Label Updates") { //$NON-NLS-1$
	public IStatus runInUIThread(IProgressMonitor monitor) {
	LabelUpdate[] updates = null;
	synchronized (TreeModelLabelProvider.this) {
	updates = (LabelUpdate[]) fComplete.toArray(new LabelUpdate[fComplete.size()]);
	fComplete = null;
	}
	//System.out.println("Changed Labels: " + updates.length);
	for (int i = 0; i < updates.length; i++) {
	updates[i].update();
	}
	return Status.OK_STATUS;
	}
	};
	job.setSystem(true);
	job.schedule(10L);
	}
	fComplete.add(update);
	}
	}

	public void addLabelUpdateListener(ILabelUpdateListener listener) {
	fLabelListeners.add(listener);
	}

	public void removeLabelUpdateListener(ILabelUpdateListener listener) {
	fLabelListeners.remove(listener);
	}

	/**
	* Notification an update request has started
	*
	* @param update
	*/
	void updateStarted(ILabelUpdate update) {
	boolean begin = false;
	synchronized (fUpdatesInProgress) {
	begin = fUpdatesInProgress.isEmpty();
	fUpdatesInProgress.add(update);
	}
	if (begin) {
	if (ModelContentProvider.DEBUG_UPDATE_SEQUENCE && (ModelContentProvider.DEBUG_PRESENTATION_ID == null \|\| ModelContentProvider.DEBUG_PRESENTATION_ID.equals(getPresentationContext().getId()))) {
	System.out.println("LABEL SEQUENCE BEGINS"); //$NON-NLS-1$
	}
	notifyUpdate(ModelContentProvider.UPDATE_SEQUENCE_BEGINS, null);
	}
	if (ModelContentProvider.DEBUG_UPDATE_SEQUENCE && (ModelContentProvider.DEBUG_PRESENTATION_ID == null \|\| ModelContentProvider.DEBUG_PRESENTATION_ID.equals(getPresentationContext().getId()))) {
	System.out.println("\tBEGIN - " + update); //$NON-NLS-1$
	}
	notifyUpdate(ModelContentProvider.UPDATE_BEGINS, update);
	}

	/**
	* Notification an update request has completed
	*
	* @param update
	*/
	void updateComplete(ILabelUpdate update) {
	boolean end = false;
	synchronized (fUpdatesInProgress) {
	fUpdatesInProgress.remove(update);
	end = fUpdatesInProgress.isEmpty();
	}
	if (ModelContentProvider.DEBUG_UPDATE_SEQUENCE && (ModelContentProvider.DEBUG_PRESENTATION_ID == null \|\| ModelContentProvider.DEBUG_PRESENTATION_ID.equals(getPresentationContext().getId()))) {
	System.out.println("\tEND - " + update); //$NON-NLS-1$
	}
	notifyUpdate(ModelContentProvider.UPDATE_COMPLETE, update);
	if (end) {
	if (ModelContentProvider.DEBUG_UPDATE_SEQUENCE && (ModelContentProvider.DEBUG_PRESENTATION_ID == null \|\| ModelContentProvider.DEBUG_PRESENTATION_ID.equals(getPresentationContext().getId()))) {
	System.out.println("LABEL SEQUENCE ENDS"); //$NON-NLS-1$
	}
	notifyUpdate(ModelContentProvider.UPDATE_SEQUENCE_COMPLETE, null);
	}
	}

	protected void notifyUpdate(final int type, final ILabelUpdate update) {
	if (!fLabelListeners.isEmpty()) {
	Object[] listeners = fLabelListeners.getListeners();
	for (int i = 0; i < listeners.length; i++) {
	final ILabelUpdateListener listener = (ILabelUpdateListener) listeners[i];
	SafeRunner.run(new ISafeRunnable() {
	public void run() throws Exception {
	switch (type) {
	case ModelContentProvider.UPDATE_SEQUENCE_BEGINS:
	listener.labelUpdatesBegin();
	break;
	case ModelContentProvider.UPDATE_SEQUENCE_COMPLETE:
	listener.labelUpdatesComplete();
	break;
	case ModelContentProvider.UPDATE_BEGINS:
	listener.labelUpdateStarted(update);
	break;
	case ModelContentProvider.UPDATE_COMPLETE:
	listener.labelUpdateComplete(update);
	break;
	}
	}
	public void handleException(Throwable exception) {
	DebugUIPlugin.log(exception);
	}
	});
	}
	}
	}

	}