bundles/org.eclipse.jst.jsp.core/src/org/eclipse/jst/jsp/core/internal/contentmodel/TaglibIndex.java - sourceediting/webtools.sourceediting - Git at Google

 /*******************************************************************************
  * Copyright (c) 2001, 2004 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.jst.jsp.core.internal.contentmodel;

 import java.io.File;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Stack;

 import org.eclipse.core.filebuffers.FileBuffers;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.resources.IResourceChangeEvent;
 import org.eclipse.core.resources.IResourceChangeListener;
 import org.eclipse.core.resources.IResourceDelta;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.Path;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.jdt.core.ElementChangedEvent;
 import org.eclipse.jdt.core.IElementChangedListener;
 import org.eclipse.jdt.core.IJavaElement;
 import org.eclipse.jdt.core.IJavaElementDelta;
 import org.eclipse.jdt.core.IJavaProject;
 import org.eclipse.jdt.core.JavaCore;
 import org.eclipse.jdt.core.JavaModelException;
 import org.eclipse.jst.jsp.core.internal.Logger;
 import org.eclipse.wst.sse.core.internal.util.StringUtils;
 import org.eclipse.wst.xml.uriresolver.internal.util.URIHelper;

 /**
  * @author nitin
  *
  * A non-extendable index manager for taglibs similar to the J2EE
  * ITaglibRegistry but lacking any ties to project natures.
  *
  * Indexing is not persisted between sessions, so new ADD events will be sent
  * to ITaglibIndexListeners during each workbench session. REMOVE events are
  * not fired on workbench shutdown. Events for TAGDIR, JAR, and WEBXML type
  * records are only fired for the .jar and web.xml file itself. The record's
  * contents should be examined for any further information.
  */
 public class TaglibIndex {

 	class ClasspathChangeListener implements IElementChangedListener {
 		Stack classpathStack = new Stack();
 		List projectsIndexed = new ArrayList(1);

 		public void elementChanged(ElementChangedEvent event) {
 			classpathStack.clear();
 			projectsIndexed.clear();
 			elementChanged(event.getDelta());
 		}

 		private void elementChanged(IJavaElementDelta delta) {
 			if (delta.getElement().getElementType() == IJavaElement.JAVA_MODEL) {
 				IJavaElementDelta[] changed = delta.getChangedChildren();
 				for (int i = 0; i < changed.length; i++) {
 					elementChanged(changed[i]);
 				}
 			}
 			else if (delta.getElement().getElementType() == IJavaElement.JAVA_PROJECT) {
 				if ((delta.getFlags() & IJavaElementDelta.F_CLASSPATH_CHANGED) != 0) {
 					IJavaElement proj = delta.getElement();
 					handleClasspathChange((IJavaProject) proj);
 				}
 			}
 		}

 		private void handleClasspathChange(IJavaProject project) {
 			classpathStack.push(project.getElementName());
 			try {
 				/* Handle changes to this project's build path */
 				IResource resource = project.getCorrespondingResource();
 				if (resource.getType() == IResource.PROJECT && !projectsIndexed.contains(resource)) {
 					projectsIndexed.add(resource);
 					boolean classpathIndexIsOld = fProjectDescriptions.containsKey(resource);
 					ProjectDescription description = createDescription((IProject) resource);
 					if (classpathIndexIsOld) {
 						description.indexClasspath();
 					}
 				}
 				/*
 				 * Update indeces for projects who include this project in
 				 * their build path (e.g. toggling the "exportation" of a
 				 * taglib JAR in this project affects the JAR's visibility in
 				 * other projects)
 				 */
 				IJavaProject[] projects = project.getJavaModel().getJavaProjects();
 				for (int i = 0; i < projects.length; i++) {
 					IJavaProject otherProject = projects[i];
 					if (StringUtils.contains(otherProject.getRequiredProjectNames(), project.getElementName(), false) && !classpathStack.contains(otherProject.getElementName())) {
 						handleClasspathChange(otherProject);
 					}
 				}
 			}
 			catch (JavaModelException e) {
 			}
 			classpathStack.pop();
 		}
 	}

 	class ResourceChangeListener implements IResourceChangeListener {
 		public void resourceChanged(IResourceChangeEvent event) {
 			switch (event.getType()) {
 				case IResourceChangeEvent.PRE_CLOSE :
 				case IResourceChangeEvent.PRE_DELETE : {
 					try {
 						// pair deltas with projects
 						IResourceDelta[] deltas = new IResourceDelta[]{event.getDelta()};
 						IProject[] projects = null;

 						if (deltas != null && deltas.length > 0) {
 							IResource resource = null;
 							if (deltas[0] != null) {
 								resource = deltas[0].getResource();
 							}
 							else {
 								resource = event.getResource();
 							}

 							if (resource != null) {
 								if (resource.getType() == IResource.ROOT) {
 									deltas = deltas[0].getAffectedChildren();
 									projects = new IProject[deltas.length];
 									for (int i = 0; i < deltas.length; i++) {
 										if (deltas[i].getResource().getType() == IResource.PROJECT) {
 											projects[i] = (IProject) deltas[i].getResource();
 										}
 									}
 								}
 								else {
 									projects = new IProject[1];
 									if (resource.getType() != IResource.PROJECT) {
 										projects[0] = resource.getProject();
 									}
 									else {
 										projects[0] = (IProject) resource;
 									}
 								}
 							}
 							for (int i = 0; i < projects.length; i++) {
 								if (_debugIndexCreation) {
 									System.out.println("TaglibIndex noticed " + projects[i].getName() + " is about to be deleted/closed"); //$NON-NLS-1$ //$NON-NLS-2$
 								}
 								ProjectDescription description = (ProjectDescription) fProjectDescriptions.remove(projects[i]);
 								if (description != null) {
 									if (_debugIndexCreation) {
 										System.out.println("removing index of " + description.fProject.getName()); //$NON-NLS-1$
 									}
 									description.clear();
 								}
 							}
 						}
 					}
 					catch (Exception e) {
 						Logger.logException("Exception while processing resource deletion", e); //$NON-NLS-1$
 					}
 				}
 				case IResourceChangeEvent.POST_CHANGE : {
 					try {
 						// pair deltas with projects
 						IResourceDelta[] deltas = new IResourceDelta[]{event.getDelta()};
 						IProject[] projects = null;

 						if (deltas != null && deltas.length > 0) {
 							IResource resource = null;
 							if (deltas[0] != null) {
 								resource = deltas[0].getResource();
 							}
 							else {
 								resource = event.getResource();
 							}

 							if (resource != null) {
 								if (resource.getType() == IResource.ROOT) {
 									deltas = deltas[0].getAffectedChildren();
 									projects = new IProject[deltas.length];
 									for (int i = 0; i < deltas.length; i++) {
 										if (deltas[i].getResource().getType() == IResource.PROJECT) {
 											projects[i] = (IProject) deltas[i].getResource();
 										}
 									}
 								}
 								else {
 									projects = new IProject[1];
 									if (resource.getType() != IResource.PROJECT) {
 										projects[0] = resource.getProject();
 									}
 									else {
 										projects[0] = (IProject) resource;
 									}
 								}
 							}
 							for (int i = 0; i < projects.length; i++) {
 								try {
 									if (deltas[i] != null && deltas[i].getKind() != IResourceDelta.REMOVED && projects[i].isAccessible()) {
 										ProjectDescription description = createDescription(projects[i]);
 										deltas[i].accept(description.getVisitor());
 									}
 									if (!projects[i].isAccessible() || (deltas[i] != null && deltas[i].getKind() == IResourceDelta.REMOVED)) {
 										if (_debugIndexCreation) {
 											System.out.println("TaglibIndex noticed " + projects[i].getName() + " is no longer accessible"); //$NON-NLS-1$ //$NON-NLS-2$
 										}
 										ProjectDescription description = (ProjectDescription) fProjectDescriptions.remove(projects[i]);
 										if (description != null) {
 											if (_debugIndexCreation) {
 												System.out.println("removing index of " + description.fProject.getName()); //$NON-NLS-1$
 											}
 											description.clear();
 										}
 									}
 								}
 								catch (CoreException e) {
 									Logger.logException(e);
 								}
 							}
 						}
 					}
 					catch (Exception e) {
 						Logger.logException("Exception while processing resource change", e); //$NON-NLS-1$
 					}
 				}
 			}
 		}
 	}

 	static final boolean _debugChangeListener = false;
 	static boolean _debugIndexCreation = "true".equalsIgnoreCase(Platform.getDebugOption("org.eclipse.jst.jsp.core/taglib/indexcreation")); //$NON-NLS-1$ //$NON-NLS-2$
 	static boolean _debugEvents = "true".equalsIgnoreCase(Platform.getDebugOption("org.eclipse.jst.jsp.core/taglib/events")); //$NON-NLS-1$ //$NON-NLS-2$
 	static final boolean _debugResolution = "true".equals(Platform.getDebugOption("org.eclipse.jst.jsp.core/taglib/resolve")); //$NON-NLS-1$ //$NON-NLS-2$

 	static TaglibIndex _instance;

 	static {
 		_instance = new TaglibIndex();
 	}

 	static void fireTaglibRecordEvent(ITaglibRecordEvent event) {
 		if(_debugEvents) {
 			System.out.println("TaglibIndex fired event:" + event); //$NON-NLS-1$
 		}
 		ITaglibIndexListener[] listeners = _instance.fTaglibIndexListeners;
 		if (listeners != null) {
 			for (int i = 0; i < listeners.length; i++) {
 				try {
 					listeners[i].indexChanged(event);
 				}
 				catch (Exception e) {
 					Logger.log(Logger.WARNING, e.getMessage());
 				}
 			}
 		}
 	}

 	/**
 	 * Returns all of the visible ITaglibRecords for the given filepath in the
 	 * workspace.
 	 *
 	 * @param workspacePath
 	 * @return
 	 */
 	public static ITaglibRecord[] getAvailableTaglibRecords(IPath workspacePath) {
 		ITaglibRecord[] records = _instance.internalGetAvailableTaglibRecords(workspacePath);
 		return records;
 	}

 	public static IPath getContextRoot(IPath path) {
 		return _instance.internalGetContextRoot(path);
 	}

 	public static void removeTaglibIndexListener(ITaglibIndexListener listener) {
 		_instance.internalRemoveTaglibIndexListener(listener);
 	}

 	/**
 	 * Find a matching ITaglibRecord given the reference.
 	 *
 	 * @param basePath -
 	 *            the workspace-relative path for IResources, full filesystem
 	 *            path otherwise
 	 * @param reference
 	 * @param crossProjects
 	 * @return
 	 */
 	public static ITaglibRecord resolve(String basePath, String reference, boolean crossProjects) {
 		ITaglibRecord result = _instance.internalResolve(basePath, reference, crossProjects);
 		if (_debugResolution) {
 			if (result == null) {
 				System.out.println("TaglibIndex could not resolve \"" + reference + "\" from " + basePath); //$NON-NLS-1$ //$NON-NLS-2$
 			}
 			else {
 				switch (result.getRecordType()) {
 					case (ITaglibRecord.TLD) : {
 						TLDRecord record = (TLDRecord) result;
 						System.out.println("TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getLocation()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 					}
 						break;
 					case (ITaglibRecord.JAR) : {
 						JarRecord record = (JarRecord) result;
 						System.out.println("TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getLocation()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 					}
 						break;
 					case (ITaglibRecord.TAGDIR) : {
 					}
 						break;
 					case (ITaglibRecord.URL) : {
 						URLRecord record = (URLRecord) result;
 						System.out.println("TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getURL()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 					}
 						break;
 				}
 			}
 		}
 		return result;
 	}

 	private ClasspathChangeListener fClasspathChangeListener = null;

 	Map fProjectDescriptions;
 	private ResourceChangeListener fResourceChangeListener;

 	private ITaglibIndexListener[] fTaglibIndexListeners = null;

 	private TaglibIndex() {
 		super();
 		fResourceChangeListener = new ResourceChangeListener();
 		ResourcesPlugin.getWorkspace().addResourceChangeListener(fResourceChangeListener, IResourceChangeEvent.POST_CHANGE);
 		fClasspathChangeListener = new ClasspathChangeListener();
 		JavaCore.addElementChangedListener(fClasspathChangeListener);
 		fProjectDescriptions = new HashMap();
 	}

 	public static void addTaglibIndexListener(ITaglibIndexListener listener) {
 		_instance.internalAddTaglibIndexListener(listener);
 	}

 	/**
 	 * @param project
 	 * @return
 	 */
 	ProjectDescription createDescription(IProject project) {
 		ProjectDescription description = (ProjectDescription) fProjectDescriptions.get(project);
 		if (description == null) {
 			description = new ProjectDescription(project);
 			description.index();
 			description.indexClasspath();
 			fProjectDescriptions.put(project, description);
 		}
 		return description;
 	}

 	private synchronized void internalAddTaglibIndexListener(ITaglibIndexListener listener) {
 		if (fTaglibIndexListeners == null) {
 			fTaglibIndexListeners = new ITaglibIndexListener[]{listener};
 		}
 		else {
 			List listeners = new ArrayList(Arrays.asList(fTaglibIndexListeners));
 			listeners.add(listener);
 			fTaglibIndexListeners = (ITaglibIndexListener[]) listeners.toArray(new ITaglibIndexListener[0]);
 		}
 	}

 	private ITaglibRecord[] internalGetAvailableTaglibRecords(IPath location) {
 		ITaglibRecord[] records = null;
 		IFile baseResource = ResourcesPlugin.getWorkspace().getRoot().getFile(location);
 		if (baseResource != null) {
 			IProject project = baseResource.getProject();
 			ProjectDescription description = createDescription(project);
 			List availableRecords = description.getAvailableTaglibRecords(location);
 			records = (ITaglibRecord[]) availableRecords.toArray(records);
 		}
 		else {
 			records = new ITaglibRecord[0];
 		}
 		return records;
 	}

 	private IPath internalGetContextRoot(IPath path) {
 		IFile baseResource = FileBuffers.getWorkspaceFileAtLocation(path);
 		if (baseResource != null) {
 			IProject project = baseResource.getProject();
 			ProjectDescription description = _instance.createDescription(project);
 			IPath rootPath = description.getLocalRoot(baseResource.getFullPath());
 			return ResourcesPlugin.getWorkspace().getRoot().getLocation().append(rootPath);
 		}
 		// try to handle out-of-workspace paths
 		IPath root = path;
 		while (root != null && !root.isRoot())
 			root = root.removeLastSegments(1);
 		if (root == null)
 			root = path;
 		return root;
 	}

 	private synchronized void internalRemoveTaglibIndexListener(ITaglibIndexListener listener) {
 		if (fTaglibIndexListeners != null) {
 			List listeners = new ArrayList(Arrays.asList(fTaglibIndexListeners));
 			listeners.remove(listener);
 			fTaglibIndexListeners = (ITaglibIndexListener[]) listeners.toArray(new ITaglibIndexListener[0]);
 		}
 	}

 	private ITaglibRecord internalResolve(String basePath, String reference, boolean crossProjects) {
 		IProject project = null;
 		ITaglibRecord resolved = null;
 		IFile baseResource = FileBuffers.getWorkspaceFileAtLocation(new Path(basePath));
 		if (baseResource != null) {
 			project = baseResource.getProject();
 			ProjectDescription description = createDescription(project);
 			resolved = description.resolve(basePath, reference);
 		}
 		else {
 			// try simple file support outside of the workspace
 			File baseFile = FileBuffers.getSystemFileAtLocation(new Path(basePath));
 			if (baseFile != null) {
 				String normalizedReference = URIHelper.normalize(reference, basePath, "/"); //$NON-NLS-1$
 				if (normalizedReference != null) {
 					TLDRecord record = new TLDRecord();
 					record.location = new Path(normalizedReference);
 					record.uri = reference;
 					resolved = record;
 				}
 			}
 		}
 		return resolved;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2001, 2004 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.jst.jsp.core.internal.contentmodel;

	import java.io.File;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.Stack;

	import org.eclipse.core.filebuffers.FileBuffers;
	import org.eclipse.core.resources.IFile;
	import org.eclipse.core.resources.IProject;
	import org.eclipse.core.resources.IResource;
	import org.eclipse.core.resources.IResourceChangeEvent;
	import org.eclipse.core.resources.IResourceChangeListener;
	import org.eclipse.core.resources.IResourceDelta;
	import org.eclipse.core.resources.ResourcesPlugin;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.Path;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.jdt.core.ElementChangedEvent;
	import org.eclipse.jdt.core.IElementChangedListener;
	import org.eclipse.jdt.core.IJavaElement;
	import org.eclipse.jdt.core.IJavaElementDelta;
	import org.eclipse.jdt.core.IJavaProject;
	import org.eclipse.jdt.core.JavaCore;
	import org.eclipse.jdt.core.JavaModelException;
	import org.eclipse.jst.jsp.core.internal.Logger;
	import org.eclipse.wst.sse.core.internal.util.StringUtils;
	import org.eclipse.wst.xml.uriresolver.internal.util.URIHelper;

	/**
	* @author nitin
	*
	* A non-extendable index manager for taglibs similar to the J2EE
	* ITaglibRegistry but lacking any ties to project natures.
	*
	* Indexing is not persisted between sessions, so new ADD events will be sent
	* to ITaglibIndexListeners during each workbench session. REMOVE events are
	* not fired on workbench shutdown. Events for TAGDIR, JAR, and WEBXML type
	* records are only fired for the .jar and web.xml file itself. The record's
	* contents should be examined for any further information.
	*/
	public class TaglibIndex {

	class ClasspathChangeListener implements IElementChangedListener {
	Stack classpathStack = new Stack();
	List projectsIndexed = new ArrayList(1);

	public void elementChanged(ElementChangedEvent event) {
	classpathStack.clear();
	projectsIndexed.clear();
	elementChanged(event.getDelta());
	}

	private void elementChanged(IJavaElementDelta delta) {
	if (delta.getElement().getElementType() == IJavaElement.JAVA_MODEL) {
	IJavaElementDelta[] changed = delta.getChangedChildren();
	for (int i = 0; i < changed.length; i++) {
	elementChanged(changed[i]);
	}
	}
	else if (delta.getElement().getElementType() == IJavaElement.JAVA_PROJECT) {
	if ((delta.getFlags() & IJavaElementDelta.F_CLASSPATH_CHANGED) != 0) {
	IJavaElement proj = delta.getElement();
	handleClasspathChange((IJavaProject) proj);
	}
	}
	}

	private void handleClasspathChange(IJavaProject project) {
	classpathStack.push(project.getElementName());
	try {
	/* Handle changes to this project's build path */
	IResource resource = project.getCorrespondingResource();
	if (resource.getType() == IResource.PROJECT && !projectsIndexed.contains(resource)) {
	projectsIndexed.add(resource);
	boolean classpathIndexIsOld = fProjectDescriptions.containsKey(resource);
	ProjectDescription description = createDescription((IProject) resource);
	if (classpathIndexIsOld) {
	description.indexClasspath();
	}
	}
	/*
	* Update indeces for projects who include this project in
	* their build path (e.g. toggling the "exportation" of a
	* taglib JAR in this project affects the JAR's visibility in
	* other projects)
	*/
	IJavaProject[] projects = project.getJavaModel().getJavaProjects();
	for (int i = 0; i < projects.length; i++) {
	IJavaProject otherProject = projects[i];
	if (StringUtils.contains(otherProject.getRequiredProjectNames(), project.getElementName(), false) && !classpathStack.contains(otherProject.getElementName())) {
	handleClasspathChange(otherProject);
	}
	}
	}
	catch (JavaModelException e) {
	}
	classpathStack.pop();
	}
	}

	class ResourceChangeListener implements IResourceChangeListener {
	public void resourceChanged(IResourceChangeEvent event) {
	switch (event.getType()) {
	case IResourceChangeEvent.PRE_CLOSE :
	case IResourceChangeEvent.PRE_DELETE : {
	try {
	// pair deltas with projects
	IResourceDelta[] deltas = new IResourceDelta[]{event.getDelta()};
	IProject[] projects = null;

	if (deltas != null && deltas.length > 0) {
	IResource resource = null;
	if (deltas[0] != null) {
	resource = deltas[0].getResource();
	}
	else {
	resource = event.getResource();
	}

	if (resource != null) {
	if (resource.getType() == IResource.ROOT) {
	deltas = deltas[0].getAffectedChildren();
	projects = new IProject[deltas.length];
	for (int i = 0; i < deltas.length; i++) {
	if (deltas[i].getResource().getType() == IResource.PROJECT) {
	projects[i] = (IProject) deltas[i].getResource();
	}
	}
	}
	else {
	projects = new IProject[1];
	if (resource.getType() != IResource.PROJECT) {
	projects[0] = resource.getProject();
	}
	else {
	projects[0] = (IProject) resource;
	}
	}
	}
	for (int i = 0; i < projects.length; i++) {
	if (_debugIndexCreation) {
	System.out.println("TaglibIndex noticed " + projects[i].getName() + " is about to be deleted/closed"); //$NON-NLS-1$ //$NON-NLS-2$
	}
	ProjectDescription description = (ProjectDescription) fProjectDescriptions.remove(projects[i]);
	if (description != null) {
	if (_debugIndexCreation) {
	System.out.println("removing index of " + description.fProject.getName()); //$NON-NLS-1$
	}
	description.clear();
	}
	}
	}
	}
	catch (Exception e) {
	Logger.logException("Exception while processing resource deletion", e); //$NON-NLS-1$
	}
	}
	case IResourceChangeEvent.POST_CHANGE : {
	try {
	// pair deltas with projects
	IResourceDelta[] deltas = new IResourceDelta[]{event.getDelta()};
	IProject[] projects = null;

	if (deltas != null && deltas.length > 0) {
	IResource resource = null;
	if (deltas[0] != null) {
	resource = deltas[0].getResource();
	}
	else {
	resource = event.getResource();
	}

	if (resource != null) {
	if (resource.getType() == IResource.ROOT) {
	deltas = deltas[0].getAffectedChildren();
	projects = new IProject[deltas.length];
	for (int i = 0; i < deltas.length; i++) {
	if (deltas[i].getResource().getType() == IResource.PROJECT) {
	projects[i] = (IProject) deltas[i].getResource();
	}
	}
	}
	else {
	projects = new IProject[1];
	if (resource.getType() != IResource.PROJECT) {
	projects[0] = resource.getProject();
	}
	else {
	projects[0] = (IProject) resource;
	}
	}
	}
	for (int i = 0; i < projects.length; i++) {
	try {
	if (deltas[i] != null && deltas[i].getKind() != IResourceDelta.REMOVED && projects[i].isAccessible()) {
	ProjectDescription description = createDescription(projects[i]);
	deltas[i].accept(description.getVisitor());
	}
	if (!projects[i].isAccessible() \|\| (deltas[i] != null && deltas[i].getKind() == IResourceDelta.REMOVED)) {
	if (_debugIndexCreation) {
	System.out.println("TaglibIndex noticed " + projects[i].getName() + " is no longer accessible"); //$NON-NLS-1$ //$NON-NLS-2$
	}
	ProjectDescription description = (ProjectDescription) fProjectDescriptions.remove(projects[i]);
	if (description != null) {
	if (_debugIndexCreation) {
	System.out.println("removing index of " + description.fProject.getName()); //$NON-NLS-1$
	}
	description.clear();
	}
	}
	}
	catch (CoreException e) {
	Logger.logException(e);
	}
	}
	}
	}
	catch (Exception e) {
	Logger.logException("Exception while processing resource change", e); //$NON-NLS-1$
	}
	}
	}
	}
	}

	static final boolean _debugChangeListener = false;
	static boolean _debugIndexCreation = "true".equalsIgnoreCase(Platform.getDebugOption("org.eclipse.jst.jsp.core/taglib/indexcreation")); //$NON-NLS-1$ //$NON-NLS-2$
	static boolean _debugEvents = "true".equalsIgnoreCase(Platform.getDebugOption("org.eclipse.jst.jsp.core/taglib/events")); //$NON-NLS-1$ //$NON-NLS-2$
	static final boolean _debugResolution = "true".equals(Platform.getDebugOption("org.eclipse.jst.jsp.core/taglib/resolve")); //$NON-NLS-1$ //$NON-NLS-2$

	static TaglibIndex _instance;

	static {
	_instance = new TaglibIndex();
	}

	static void fireTaglibRecordEvent(ITaglibRecordEvent event) {
	if(_debugEvents) {
	System.out.println("TaglibIndex fired event:" + event); //$NON-NLS-1$
	}
	ITaglibIndexListener[] listeners = _instance.fTaglibIndexListeners;
	if (listeners != null) {
	for (int i = 0; i < listeners.length; i++) {
	try {
	listeners[i].indexChanged(event);
	}
	catch (Exception e) {
	Logger.log(Logger.WARNING, e.getMessage());
	}
	}
	}
	}

	/**
	* Returns all of the visible ITaglibRecords for the given filepath in the
	* workspace.
	*
	* @param workspacePath
	* @return
	*/
	public static ITaglibRecord[] getAvailableTaglibRecords(IPath workspacePath) {
	ITaglibRecord[] records = _instance.internalGetAvailableTaglibRecords(workspacePath);
	return records;
	}

	public static IPath getContextRoot(IPath path) {
	return _instance.internalGetContextRoot(path);
	}

	public static void removeTaglibIndexListener(ITaglibIndexListener listener) {
	_instance.internalRemoveTaglibIndexListener(listener);
	}

	/**
	* Find a matching ITaglibRecord given the reference.
	*
	* @param basePath -
	* the workspace-relative path for IResources, full filesystem
	* path otherwise
	* @param reference
	* @param crossProjects
	* @return
	*/
	public static ITaglibRecord resolve(String basePath, String reference, boolean crossProjects) {
	ITaglibRecord result = _instance.internalResolve(basePath, reference, crossProjects);
	if (_debugResolution) {
	if (result == null) {
	System.out.println("TaglibIndex could not resolve \"" + reference + "\" from " + basePath); //$NON-NLS-1$ //$NON-NLS-2$
	}
	else {
	switch (result.getRecordType()) {
	case (ITaglibRecord.TLD) : {
	TLDRecord record = (TLDRecord) result;
	System.out.println("TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getLocation()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
	}
	break;
	case (ITaglibRecord.JAR) : {
	JarRecord record = (JarRecord) result;
	System.out.println("TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getLocation()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
	}
	break;
	case (ITaglibRecord.TAGDIR) : {
	}
	break;
	case (ITaglibRecord.URL) : {
	URLRecord record = (URLRecord) result;
	System.out.println("TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getURL()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
	}
	break;
	}
	}
	}
	return result;
	}

	private ClasspathChangeListener fClasspathChangeListener = null;

	Map fProjectDescriptions;
	private ResourceChangeListener fResourceChangeListener;

	private ITaglibIndexListener[] fTaglibIndexListeners = null;

	private TaglibIndex() {
	super();
	fResourceChangeListener = new ResourceChangeListener();
	ResourcesPlugin.getWorkspace().addResourceChangeListener(fResourceChangeListener, IResourceChangeEvent.POST_CHANGE);
	fClasspathChangeListener = new ClasspathChangeListener();
	JavaCore.addElementChangedListener(fClasspathChangeListener);
	fProjectDescriptions = new HashMap();
	}

	public static void addTaglibIndexListener(ITaglibIndexListener listener) {
	_instance.internalAddTaglibIndexListener(listener);
	}

	/**
	* @param project
	* @return
	*/
	ProjectDescription createDescription(IProject project) {
	ProjectDescription description = (ProjectDescription) fProjectDescriptions.get(project);
	if (description == null) {
	description = new ProjectDescription(project);
	description.index();
	description.indexClasspath();
	fProjectDescriptions.put(project, description);
	}
	return description;
	}

	private synchronized void internalAddTaglibIndexListener(ITaglibIndexListener listener) {
	if (fTaglibIndexListeners == null) {
	fTaglibIndexListeners = new ITaglibIndexListener[]{listener};
	}
	else {
	List listeners = new ArrayList(Arrays.asList(fTaglibIndexListeners));
	listeners.add(listener);
	fTaglibIndexListeners = (ITaglibIndexListener[]) listeners.toArray(new ITaglibIndexListener[0]);
	}
	}

	private ITaglibRecord[] internalGetAvailableTaglibRecords(IPath location) {
	ITaglibRecord[] records = null;
	IFile baseResource = ResourcesPlugin.getWorkspace().getRoot().getFile(location);
	if (baseResource != null) {
	IProject project = baseResource.getProject();
	ProjectDescription description = createDescription(project);
	List availableRecords = description.getAvailableTaglibRecords(location);
	records = (ITaglibRecord[]) availableRecords.toArray(records);
	}
	else {
	records = new ITaglibRecord[0];
	}
	return records;
	}

	private IPath internalGetContextRoot(IPath path) {
	IFile baseResource = FileBuffers.getWorkspaceFileAtLocation(path);
	if (baseResource != null) {
	IProject project = baseResource.getProject();
	ProjectDescription description = _instance.createDescription(project);
	IPath rootPath = description.getLocalRoot(baseResource.getFullPath());
	return ResourcesPlugin.getWorkspace().getRoot().getLocation().append(rootPath);
	}
	// try to handle out-of-workspace paths
	IPath root = path;
	while (root != null && !root.isRoot())
	root = root.removeLastSegments(1);
	if (root == null)
	root = path;
	return root;
	}

	private synchronized void internalRemoveTaglibIndexListener(ITaglibIndexListener listener) {
	if (fTaglibIndexListeners != null) {
	List listeners = new ArrayList(Arrays.asList(fTaglibIndexListeners));
	listeners.remove(listener);
	fTaglibIndexListeners = (ITaglibIndexListener[]) listeners.toArray(new ITaglibIndexListener[0]);
	}
	}

	private ITaglibRecord internalResolve(String basePath, String reference, boolean crossProjects) {
	IProject project = null;
	ITaglibRecord resolved = null;
	IFile baseResource = FileBuffers.getWorkspaceFileAtLocation(new Path(basePath));
	if (baseResource != null) {
	project = baseResource.getProject();
	ProjectDescription description = createDescription(project);
	resolved = description.resolve(basePath, reference);
	}
	else {
	// try simple file support outside of the workspace
	File baseFile = FileBuffers.getSystemFileAtLocation(new Path(basePath));
	if (baseFile != null) {
	String normalizedReference = URIHelper.normalize(reference, basePath, "/"); //$NON-NLS-1$
	if (normalizedReference != null) {
	TLDRecord record = new TLDRecord();
	record.location = new Path(normalizedReference);
	record.uri = reference;
	resolved = record;
	}
	}
	}
	return resolved;
	}
	}