bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorPipelineService.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2006, 2007 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
  *******************************************************************************/

 package org.eclipse.ui.internal.navigator;

 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.LinkedHashSet;
 import java.util.Set;

 import org.eclipse.jface.viewers.TreePath;
 import org.eclipse.ui.internal.navigator.extensions.NavigatorContentDescriptor;
 import org.eclipse.ui.internal.navigator.extensions.NavigatorContentExtension;
 import org.eclipse.ui.navigator.INavigatorContentDescriptor;
 import org.eclipse.ui.navigator.INavigatorPipelineService;
 import org.eclipse.ui.navigator.IPipelinedTreeContentProvider;
 import org.eclipse.ui.navigator.PipelinedShapeModification;
 import org.eclipse.ui.navigator.PipelinedViewerUpdate;

 /**
  * @since 3.2
  *
  */
 public class NavigatorPipelineService implements INavigatorPipelineService {

 	private NavigatorContentService contentService;

 	/**
 	 * Create a pipeline assistnat for the given content service.
 	 *
 	 * @param aContentService
 	 *            The content service that will drive this pipeline assistant.
 	 */
 	public NavigatorPipelineService(NavigatorContentService aContentService) {
 		contentService = aContentService;
 	}

 	/**
 	 * Intercept attempts to add elements directly to the viewer.
 	 *
 	 * <p>
 	 * For content extensions that reshape the structure of children in a
 	 * viewer, their overridden extensions may sometimes use optimized refreshes
 	 * to add elements to the tree. These attempts must be intercepted and
 	 * mapped to the correct set of model elements in the overridding extension.
 	 * Clients may add, remove, or modify elements in the given set of added
 	 * children. Clients should return a set for downstream extensions to
 	 * massage further.
 	 * </p>
 	 * <p>
 	 * <b>Clients should not call any of the add, remove, refresh, or update
 	 * methods on the viewer from this method or any code invoked by the
 	 * implementation of this method.</b>
 	 * </p>
 	 *
 	 * @param anAddModification
 	 *            The shape modification which contains the current suggested
 	 *            parent and children. Clients may modify this parameter
 	 *            directly and return it as the new shape modification.
 	 * @return The new shape modification to use. Clients should <b>never</b>
 	 *         return <b>null</b> from this method.
 	 */
 	public PipelinedShapeModification interceptAdd(
 			PipelinedShapeModification anAddModification) {

 		ContributorTrackingSet trackedSet =(ContributorTrackingSet) anAddModification.getChildren();

 		Set contentDescriptors = contentService.findDescriptorsByTriggerPoint(anAddModification.getParent());


 		for (Iterator descriptorsItr = contentDescriptors.iterator(); descriptorsItr.hasNext();) {
 			INavigatorContentDescriptor descriptor = (INavigatorContentDescriptor) descriptorsItr.next();
 			pipelineInterceptAdd(anAddModification, trackedSet, descriptor);
 		}

 		// for consistency, we register the contribution from our best known match
 		registerContribution(anAddModification.getParent(), anAddModification.getChildren().toArray());
 		return anAddModification;

 	}

 	/**
 	 * @param parent The object to which data was contributed
 	 * @param contributions Data contributed to the viewer
 	 */
 	private void registerContribution(Object parent, Object[] contributions) {

 		// returns an array sorted by priority
 		Set possibleContributors = contentService.findDescriptorsByTriggerPoint(parent);
 		Set possibleMatches = null;
 		for (int i = 0; i < contributions.length; i++) {
 			// returns an array sorted by reverse priority
 			possibleMatches = contentService.findDescriptorsWithPossibleChild(contributions[i]);
 			NavigatorContentDescriptor[] descriptors = (NavigatorContentDescriptor[]) possibleMatches.toArray(new NavigatorContentDescriptor[possibleMatches.size()]);
 			for (int indx = possibleMatches.size()-1; indx > -1; indx--) {

 				// terminates once the highest priority match is found for this child
 				if(possibleContributors.contains(descriptors[indx])) {
 					contentService.rememberContribution(descriptors[indx], contributions[i]);
 					break;
 				}

 			}
 		}
 	}

 	private void pipelineInterceptAdd(PipelinedShapeModification anAddModification, ContributorTrackingSet trackedSet, INavigatorContentDescriptor descriptor) {
 		if(descriptor.hasOverridingExtensions()) {
 			Set overridingDescriptors = descriptor.getOverriddingExtensions();
 			for (Iterator overridingDescriptorsItr = overridingDescriptors.iterator(); overridingDescriptorsItr
 					.hasNext();) {
 				INavigatorContentDescriptor overridingDescriptor = (INavigatorContentDescriptor) overridingDescriptorsItr.next();
 				if(contentService.isVisible(overridingDescriptor.getId()) && contentService.isActive(overridingDescriptor.getId())) {
 					trackedSet.setContributor((NavigatorContentDescriptor) overridingDescriptor);
 					NavigatorContentExtension extension = contentService.getExtension(overridingDescriptor);
 					((IPipelinedTreeContentProvider) extension.internalGetContentProvider()).interceptAdd(anAddModification);
 					trackedSet.setContributor(null);
 					pipelineInterceptAdd(anAddModification, trackedSet, overridingDescriptor);
 				}
 			}
 		}
 	}


 	/**
 	 * Intercept attempts to remove elements directly from the viewer.
 	 *
 	 * <p>
 	 * For content extensions that reshape the structure of children in a
 	 * viewer, their overridden extensions may sometimes use optimized refreshes
 	 * to remove elements to the tree. These attempts must be intercepted and
 	 * mapped to the correct set of model elements in the overridding extension.
 	 * Clients may add, remove, or modify elements in the given set of removed
 	 * children. Clients should return a set for downstream extensions to
 	 * massage further.
 	 * </p>
 	 * <p>
 	 * <b>Clients should not call any of the add, remove, refresh, or update
 	 * methods on the viewer from this method or any code invoked by the
 	 * implementation of this method.</b>
 	 * </p>
 	 *
 	 * @param aRemoveModification
 	 *            The shape modification which contains the current suggested
 	 *            parent and children. Clients may modify this parameter
 	 *            directly and return it as the new shape modification.
 	 * @return The new shape modification to use. Clients should <b>never</b>
 	 *         return <b>null</b> from this method.
 	 */
 	public PipelinedShapeModification interceptRemove(
 			PipelinedShapeModification aRemoveModification) {

 		ContributorTrackingSet trackedSet =(ContributorTrackingSet) aRemoveModification.getChildren();

 		Set interestedExtensions = new LinkedHashSet();
 		for (Iterator iter = trackedSet.iterator(); iter.hasNext();) {
 			Object element = (Object) iter.next();
 			if(element instanceof TreePath) {
 				interestedExtensions.addAll(contentService.findOverrideableContentExtensionsForPossibleChild(((TreePath)element).getLastSegment()));
 			} else {
 				interestedExtensions = contentService.findOverrideableContentExtensionsForPossibleChild(element);

 			}
 		}
 		for (Iterator overridingExtensionsIter = interestedExtensions.iterator(); overridingExtensionsIter.hasNext();)
 			pipelineInterceptRemove(aRemoveModification, trackedSet, (NavigatorContentExtension) overridingExtensionsIter.next());
 		return aRemoveModification;
 	}


 	private void pipelineInterceptRemove(PipelinedShapeModification aRemoveModification, ContributorTrackingSet trackedSet, NavigatorContentExtension overrideableExtension) {


 		try {
 			NavigatorContentExtension overridingExtension = null;
 			Set overridingExtensions = new LinkedHashSet();
 			for (Iterator iter = trackedSet.iterator(); iter.hasNext();) {
 				Object element = (Object) iter.next();
 				if(element instanceof TreePath) {
 					overridingExtensions.addAll(Arrays.asList(overrideableExtension.getOverridingExtensionsForPossibleChild(((TreePath)element).getLastSegment())));
 				} else {
 					overridingExtensions.addAll(Arrays.asList(overrideableExtension.getOverridingExtensionsForPossibleChild(element)));
 				}
 			}

 			for (Iterator extensionsItr = overridingExtensions.iterator(); extensionsItr.hasNext();) {
 				overridingExtension = (NavigatorContentExtension) extensionsItr.next();
 				trackedSet.setContributor((NavigatorContentDescriptor) overridingExtension.getDescriptor());
 				if (overridingExtension.getContentProvider() instanceof IPipelinedTreeContentProvider) {
 					((IPipelinedTreeContentProvider) overridingExtension.getContentProvider()).interceptRemove(aRemoveModification);
 				}
 				trackedSet.setContributor(null);
 				if(overridingExtension.getDescriptor().hasOverridingExtensions())
 					pipelineInterceptRemove(aRemoveModification, trackedSet, overridingExtension);

 			}

 		} catch (Throwable e) {
 			String msg = e.getMessage() != null ? e.getMessage()  : e.toString();
 			NavigatorPlugin.logError(0, msg, e);
 		}
 	}

 	/**
 	 * Intercept calls to viewer <code>refresh()</code> methods.
 	 *
 	 * <p>
 	 * Clients may modify the given update to add or remove the elements to be
 	 * refreshed. Clients may return the same instance that was passed in for
 	 * the next downstream extension.
 	 * </p>
 	 *
 	 * <p>
 	 * <b>Clients should not call any of the add, remove, refresh, or update
 	 * methods on the viewer from this method or any code invoked by the
 	 * implementation of this method.</b>
 	 * </p>
 	 *
 	 * @param aRefreshSynchronization
 	 *            The (current) refresh update to execute against the viewer.
 	 * @return The (potentially reshaped) refresh to execute against the viewer.
 	 */
 	public boolean interceptRefresh(
 			PipelinedViewerUpdate aRefreshSynchronization) {

 		boolean pipelined = false;
 		Object refreshable = null;
 		Set overrideableExtensions = new LinkedHashSet();
 		for (Iterator iter = aRefreshSynchronization.getRefreshTargets().iterator(); iter.hasNext();) {
 			refreshable = iter.next();
 			overrideableExtensions.addAll(contentService.findOverrideableContentExtensionsForPossibleChild(refreshable));
 		}
 		for (Iterator overrideableExtensionItr = overrideableExtensions.iterator(); overrideableExtensionItr.hasNext();) {
 			pipelined |= pipelineInterceptRefresh((NavigatorContentExtension) overrideableExtensionItr.next(), aRefreshSynchronization, refreshable);
 		}

 		return pipelined;

 	}

 	private boolean pipelineInterceptRefresh(NavigatorContentExtension overrideableExtension,
 			PipelinedViewerUpdate aRefreshSynchronization, Object refreshable) {

 		boolean intercepted = false;

 		NavigatorContentExtension[] overridingExtensionsForPossibleChild = overrideableExtension.getOverridingExtensionsForPossibleChild(refreshable);
 		for (int i=0; i<overridingExtensionsForPossibleChild.length; i++) {
 			try {
 				if (overridingExtensionsForPossibleChild[i].getContentProvider() instanceof IPipelinedTreeContentProvider) {

 					intercepted |= ((IPipelinedTreeContentProvider) overridingExtensionsForPossibleChild[i]
 							.getContentProvider())
 							.interceptRefresh(aRefreshSynchronization);

 					if (overridingExtensionsForPossibleChild[i].getDescriptor().hasOverridingExtensions())
 						intercepted |= pipelineInterceptRefresh(overridingExtensionsForPossibleChild[i], aRefreshSynchronization, refreshable);
 				}
 			} catch (Throwable e) {
 				String msg = e.getMessage() != null ? e.getMessage()  : e.toString();
 				NavigatorPlugin.logError(0, msg, e);
 			}
 		}

 		return intercepted;
 	}


 	/**
 	 * Intercept calls to viewer <code>update()</code> methods.
 	 *
 	 * <p>
 	 * Clients may modify the given update to add or remove the elements to be
 	 * updated. Clients may also add or remove properties for the given targets
 	 * to optimize the refresh. Clients may return the same instance that was
 	 * passed in for the next downstream extension.
 	 * </p>
 	 *
 	 * <p>
 	 * <b>Clients should not call any of the add, remove, refresh, or update
 	 * methods on the viewer from this method or any code invoked by the
 	 * implementation of this method.</b>
 	 * </p>
 	 *
 	 * @param anUpdateSynchronization
 	 *            The (current) update to execute against the viewer.
 	 * @return The (potentially reshaped) update to execute against the viewer.
 	 */
 	public boolean interceptUpdate(
 			PipelinedViewerUpdate anUpdateSynchronization) {

 		boolean pipelined = false;
 		Object refreshable = null;

 		Set overrideableExtensions = new LinkedHashSet();
 		for (Iterator iter = anUpdateSynchronization.getRefreshTargets().iterator(); iter.hasNext();) {
 			refreshable = iter.next();
 			overrideableExtensions.addAll(contentService.findOverrideableContentExtensionsForPossibleChild(refreshable));
 		}
 		for (Iterator overrideableExtensionItr = overrideableExtensions.iterator(); overrideableExtensionItr.hasNext();) {
 			pipelined |= pipelineInterceptUpdate((NavigatorContentExtension) overrideableExtensionItr.next(), anUpdateSynchronization, refreshable);
 		}

 		return pipelined;

 	}

 	private boolean pipelineInterceptUpdate(NavigatorContentExtension overrideableExtension,
 					PipelinedViewerUpdate anUpdateSynchronization, Object refreshable) {

 		boolean intercepted = false;
 		NavigatorContentExtension[] overridingExtensionsForPossibleChild = overrideableExtension.getOverridingExtensionsForPossibleChild(refreshable);
 		for (int i=0; i<overridingExtensionsForPossibleChild.length; i++) {
 			try {
 				if (overridingExtensionsForPossibleChild[i].getContentProvider() instanceof IPipelinedTreeContentProvider) {

 					intercepted |= ((IPipelinedTreeContentProvider) overridingExtensionsForPossibleChild[i]
 							.getContentProvider())
 							.interceptUpdate(anUpdateSynchronization);

 					if (overridingExtensionsForPossibleChild[i].getDescriptor().hasOverridingExtensions())
 						intercepted |= pipelineInterceptUpdate(overridingExtensionsForPossibleChild[i], anUpdateSynchronization, refreshable);
 				}
 			} catch (Throwable e) {
 				String msg = e.getMessage() != null ? e.getMessage()  : e.toString();
 				NavigatorPlugin.logError(0, msg, e);
 			}
 		}

 		return intercepted;
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2006, 2007 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
	*******************************************************************************/

	package org.eclipse.ui.internal.navigator;

	import java.util.Arrays;
	import java.util.Iterator;
	import java.util.LinkedHashSet;
	import java.util.Set;

	import org.eclipse.jface.viewers.TreePath;
	import org.eclipse.ui.internal.navigator.extensions.NavigatorContentDescriptor;
	import org.eclipse.ui.internal.navigator.extensions.NavigatorContentExtension;
	import org.eclipse.ui.navigator.INavigatorContentDescriptor;
	import org.eclipse.ui.navigator.INavigatorPipelineService;
	import org.eclipse.ui.navigator.IPipelinedTreeContentProvider;
	import org.eclipse.ui.navigator.PipelinedShapeModification;
	import org.eclipse.ui.navigator.PipelinedViewerUpdate;

	/**
	* @since 3.2
	*
	*/
	public class NavigatorPipelineService implements INavigatorPipelineService {

	private NavigatorContentService contentService;

	/**
	* Create a pipeline assistnat for the given content service.
	*
	* @param aContentService
	* The content service that will drive this pipeline assistant.
	*/
	public NavigatorPipelineService(NavigatorContentService aContentService) {
	contentService = aContentService;
	}

	/**
	* Intercept attempts to add elements directly to the viewer.
	*
	* <p>
	* For content extensions that reshape the structure of children in a
	* viewer, their overridden extensions may sometimes use optimized refreshes
	* to add elements to the tree. These attempts must be intercepted and
	* mapped to the correct set of model elements in the overridding extension.
	* Clients may add, remove, or modify elements in the given set of added
	* children. Clients should return a set for downstream extensions to
	* massage further.
	* </p>
	* <p>
	* <b>Clients should not call any of the add, remove, refresh, or update
	* methods on the viewer from this method or any code invoked by the
	* implementation of this method.</b>
	* </p>
	*
	* @param anAddModification
	* The shape modification which contains the current suggested
	* parent and children. Clients may modify this parameter
	* directly and return it as the new shape modification.
	* @return The new shape modification to use. Clients should <b>never</b>
	* return <b>null</b> from this method.
	*/
	public PipelinedShapeModification interceptAdd(
	PipelinedShapeModification anAddModification) {

	ContributorTrackingSet trackedSet =(ContributorTrackingSet) anAddModification.getChildren();

	Set contentDescriptors = contentService.findDescriptorsByTriggerPoint(anAddModification.getParent());


	for (Iterator descriptorsItr = contentDescriptors.iterator(); descriptorsItr.hasNext();) {
	INavigatorContentDescriptor descriptor = (INavigatorContentDescriptor) descriptorsItr.next();
	pipelineInterceptAdd(anAddModification, trackedSet, descriptor);
	}

	// for consistency, we register the contribution from our best known match
	registerContribution(anAddModification.getParent(), anAddModification.getChildren().toArray());
	return anAddModification;

	}

	/**
	* @param parent The object to which data was contributed
	* @param contributions Data contributed to the viewer
	*/
	private void registerContribution(Object parent, Object[] contributions) {

	// returns an array sorted by priority
	Set possibleContributors = contentService.findDescriptorsByTriggerPoint(parent);
	Set possibleMatches = null;
	for (int i = 0; i < contributions.length; i++) {
	// returns an array sorted by reverse priority
	possibleMatches = contentService.findDescriptorsWithPossibleChild(contributions[i]);
	NavigatorContentDescriptor[] descriptors = (NavigatorContentDescriptor[]) possibleMatches.toArray(new NavigatorContentDescriptor[possibleMatches.size()]);
	for (int indx = possibleMatches.size()-1; indx > -1; indx--) {

	// terminates once the highest priority match is found for this child
	if(possibleContributors.contains(descriptors[indx])) {
	contentService.rememberContribution(descriptors[indx], contributions[i]);
	break;
	}

	}
	}
	}

	private void pipelineInterceptAdd(PipelinedShapeModification anAddModification, ContributorTrackingSet trackedSet, INavigatorContentDescriptor descriptor) {
	if(descriptor.hasOverridingExtensions()) {
	Set overridingDescriptors = descriptor.getOverriddingExtensions();
	for (Iterator overridingDescriptorsItr = overridingDescriptors.iterator(); overridingDescriptorsItr
	.hasNext();) {
	INavigatorContentDescriptor overridingDescriptor = (INavigatorContentDescriptor) overridingDescriptorsItr.next();
	if(contentService.isVisible(overridingDescriptor.getId()) && contentService.isActive(overridingDescriptor.getId())) {
	trackedSet.setContributor((NavigatorContentDescriptor) overridingDescriptor);
	NavigatorContentExtension extension = contentService.getExtension(overridingDescriptor);
	((IPipelinedTreeContentProvider) extension.internalGetContentProvider()).interceptAdd(anAddModification);
	trackedSet.setContributor(null);
	pipelineInterceptAdd(anAddModification, trackedSet, overridingDescriptor);
	}
	}
	}
	}


	/**
	* Intercept attempts to remove elements directly from the viewer.
	*
	* <p>
	* For content extensions that reshape the structure of children in a
	* viewer, their overridden extensions may sometimes use optimized refreshes
	* to remove elements to the tree. These attempts must be intercepted and
	* mapped to the correct set of model elements in the overridding extension.
	* Clients may add, remove, or modify elements in the given set of removed
	* children. Clients should return a set for downstream extensions to
	* massage further.
	* </p>
	* <p>
	* <b>Clients should not call any of the add, remove, refresh, or update
	* methods on the viewer from this method or any code invoked by the
	* implementation of this method.</b>
	* </p>
	*
	* @param aRemoveModification
	* The shape modification which contains the current suggested
	* parent and children. Clients may modify this parameter
	* directly and return it as the new shape modification.
	* @return The new shape modification to use. Clients should <b>never</b>
	* return <b>null</b> from this method.
	*/
	public PipelinedShapeModification interceptRemove(
	PipelinedShapeModification aRemoveModification) {

	ContributorTrackingSet trackedSet =(ContributorTrackingSet) aRemoveModification.getChildren();

	Set interestedExtensions = new LinkedHashSet();
	for (Iterator iter = trackedSet.iterator(); iter.hasNext();) {
	Object element = (Object) iter.next();
	if(element instanceof TreePath) {
	interestedExtensions.addAll(contentService.findOverrideableContentExtensionsForPossibleChild(((TreePath)element).getLastSegment()));
	} else {
	interestedExtensions = contentService.findOverrideableContentExtensionsForPossibleChild(element);

	}
	}
	for (Iterator overridingExtensionsIter = interestedExtensions.iterator(); overridingExtensionsIter.hasNext();)
	pipelineInterceptRemove(aRemoveModification, trackedSet, (NavigatorContentExtension) overridingExtensionsIter.next());
	return aRemoveModification;
	}


	private void pipelineInterceptRemove(PipelinedShapeModification aRemoveModification, ContributorTrackingSet trackedSet, NavigatorContentExtension overrideableExtension) {


	try {
	NavigatorContentExtension overridingExtension = null;
	Set overridingExtensions = new LinkedHashSet();
	for (Iterator iter = trackedSet.iterator(); iter.hasNext();) {
	Object element = (Object) iter.next();
	if(element instanceof TreePath) {
	overridingExtensions.addAll(Arrays.asList(overrideableExtension.getOverridingExtensionsForPossibleChild(((TreePath)element).getLastSegment())));
	} else {
	overridingExtensions.addAll(Arrays.asList(overrideableExtension.getOverridingExtensionsForPossibleChild(element)));
	}
	}

	for (Iterator extensionsItr = overridingExtensions.iterator(); extensionsItr.hasNext();) {
	overridingExtension = (NavigatorContentExtension) extensionsItr.next();
	trackedSet.setContributor((NavigatorContentDescriptor) overridingExtension.getDescriptor());
	if (overridingExtension.getContentProvider() instanceof IPipelinedTreeContentProvider) {
	((IPipelinedTreeContentProvider) overridingExtension.getContentProvider()).interceptRemove(aRemoveModification);
	}
	trackedSet.setContributor(null);
	if(overridingExtension.getDescriptor().hasOverridingExtensions())
	pipelineInterceptRemove(aRemoveModification, trackedSet, overridingExtension);

	}

	} catch (Throwable e) {
	String msg = e.getMessage() != null ? e.getMessage() : e.toString();
	NavigatorPlugin.logError(0, msg, e);
	}
	}

	/**
	* Intercept calls to viewer <code>refresh()</code> methods.
	*
	* <p>
	* Clients may modify the given update to add or remove the elements to be
	* refreshed. Clients may return the same instance that was passed in for
	* the next downstream extension.
	* </p>
	*
	* <p>
	* <b>Clients should not call any of the add, remove, refresh, or update
	* methods on the viewer from this method or any code invoked by the
	* implementation of this method.</b>
	* </p>
	*
	* @param aRefreshSynchronization
	* The (current) refresh update to execute against the viewer.
	* @return The (potentially reshaped) refresh to execute against the viewer.
	*/
	public boolean interceptRefresh(
	PipelinedViewerUpdate aRefreshSynchronization) {

	boolean pipelined = false;
	Object refreshable = null;
	Set overrideableExtensions = new LinkedHashSet();
	for (Iterator iter = aRefreshSynchronization.getRefreshTargets().iterator(); iter.hasNext();) {
	refreshable = iter.next();
	overrideableExtensions.addAll(contentService.findOverrideableContentExtensionsForPossibleChild(refreshable));
	}
	for (Iterator overrideableExtensionItr = overrideableExtensions.iterator(); overrideableExtensionItr.hasNext();) {
	pipelined \|= pipelineInterceptRefresh((NavigatorContentExtension) overrideableExtensionItr.next(), aRefreshSynchronization, refreshable);
	}

	return pipelined;

	}

	private boolean pipelineInterceptRefresh(NavigatorContentExtension overrideableExtension,
	PipelinedViewerUpdate aRefreshSynchronization, Object refreshable) {

	boolean intercepted = false;

	NavigatorContentExtension[] overridingExtensionsForPossibleChild = overrideableExtension.getOverridingExtensionsForPossibleChild(refreshable);
	for (int i=0; i<overridingExtensionsForPossibleChild.length; i++) {
	try {
	if (overridingExtensionsForPossibleChild[i].getContentProvider() instanceof IPipelinedTreeContentProvider) {

	intercepted \|= ((IPipelinedTreeContentProvider) overridingExtensionsForPossibleChild[i]
	.getContentProvider())
	.interceptRefresh(aRefreshSynchronization);

	if (overridingExtensionsForPossibleChild[i].getDescriptor().hasOverridingExtensions())
	intercepted \|= pipelineInterceptRefresh(overridingExtensionsForPossibleChild[i], aRefreshSynchronization, refreshable);
	}
	} catch (Throwable e) {
	String msg = e.getMessage() != null ? e.getMessage() : e.toString();
	NavigatorPlugin.logError(0, msg, e);
	}
	}

	return intercepted;
	}



	/**
	* Intercept calls to viewer <code>update()</code> methods.
	*
	* <p>
	* Clients may modify the given update to add or remove the elements to be
	* updated. Clients may also add or remove properties for the given targets
	* to optimize the refresh. Clients may return the same instance that was
	* passed in for the next downstream extension.
	* </p>
	*
	* <p>
	* <b>Clients should not call any of the add, remove, refresh, or update
	* methods on the viewer from this method or any code invoked by the
	* implementation of this method.</b>
	* </p>
	*
	* @param anUpdateSynchronization
	* The (current) update to execute against the viewer.
	* @return The (potentially reshaped) update to execute against the viewer.
	*/
	public boolean interceptUpdate(
	PipelinedViewerUpdate anUpdateSynchronization) {

	boolean pipelined = false;
	Object refreshable = null;

	Set overrideableExtensions = new LinkedHashSet();
	for (Iterator iter = anUpdateSynchronization.getRefreshTargets().iterator(); iter.hasNext();) {
	refreshable = iter.next();
	overrideableExtensions.addAll(contentService.findOverrideableContentExtensionsForPossibleChild(refreshable));
	}
	for (Iterator overrideableExtensionItr = overrideableExtensions.iterator(); overrideableExtensionItr.hasNext();) {
	pipelined \|= pipelineInterceptUpdate((NavigatorContentExtension) overrideableExtensionItr.next(), anUpdateSynchronization, refreshable);
	}

	return pipelined;

	}

	private boolean pipelineInterceptUpdate(NavigatorContentExtension overrideableExtension,
	PipelinedViewerUpdate anUpdateSynchronization, Object refreshable) {

	boolean intercepted = false;
	NavigatorContentExtension[] overridingExtensionsForPossibleChild = overrideableExtension.getOverridingExtensionsForPossibleChild(refreshable);
	for (int i=0; i<overridingExtensionsForPossibleChild.length; i++) {
	try {
	if (overridingExtensionsForPossibleChild[i].getContentProvider() instanceof IPipelinedTreeContentProvider) {

	intercepted \|= ((IPipelinedTreeContentProvider) overridingExtensionsForPossibleChild[i]
	.getContentProvider())
	.interceptUpdate(anUpdateSynchronization);

	if (overridingExtensionsForPossibleChild[i].getDescriptor().hasOverridingExtensions())
	intercepted \|= pipelineInterceptUpdate(overridingExtensionsForPossibleChild[i], anUpdateSynchronization, refreshable);
	}
	} catch (Throwable e) {
	String msg = e.getMessage() != null ? e.getMessage() : e.toString();
	NavigatorPlugin.logError(0, msg, e);
	}
	}

	return intercepted;
	}

	}