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

 /*******************************************************************************
  * Copyright (c) 2005 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.taglib;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Hashtable;
 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.core.runtime.jobs.ILock;
 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.utils.StringUtils;
 import org.osgi.framework.Bundle;

 /**
  * A non-extendable index manager for taglibs similar to the previous J2EE
  * ITaglibRegistry but lacking any ties to project natures. Each record
  * returned from the index represents a single tag library descriptor.
  *
  * 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. The record's contents should be examined
  * for any further information.
  *
  * @since 1.0
  */
 public final class TaglibIndex {
 	class ClasspathChangeListener implements IElementChangedListener {
 		Stack classpathStack = new Stack();
 		List projectsIndexed = new ArrayList(1);

 		public void elementChanged(ElementChangedEvent event) {
 			if (!isIndexAvailable())
 				return;
 			try {
 				LOCK.acquire();
 				classpathStack.clear();
 				projectsIndexed.clear();
 				elementChanged(event.getDelta());
 			}
 			finally {
 				LOCK.release();
 			}
 		}

 		private void elementChanged(IJavaElementDelta delta) {
 			if (frameworkIsShuttingDown())
 				return;

 			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) {
 			if (frameworkIsShuttingDown())
 				return;

 			/*
 			 * Loops in the build paths could cause us to pop more than we
 			 * push
 			 */
 			if (classpathStack.contains(project.getElementName()))
 				return;

 			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)) {
 					ProjectDescription description = getDescription((IProject) resource);
 					if (description != null && !frameworkIsShuttingDown()) {
 						projectsIndexed.add(resource);
 						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()) && !frameworkIsShuttingDown()) {
 						handleClasspathChange(otherProject);
 					}
 				}
 			}
 			catch (JavaModelException e) {
 			}
 			classpathStack.pop();

 		}
 	}

 	class ResourceChangeListener implements IResourceChangeListener {
 		public void resourceChanged(IResourceChangeEvent event) {
 			if (!isIndexAvailable())
 				return;
 			try {
 				LOCK.acquire();
 				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) {
 										Logger.log(Logger.INFO_DEBUG, "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) {
 											Logger.log(Logger.INFO_DEBUG, "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 = getDescription(projects[i]);
 											if (description != null && !frameworkIsShuttingDown()) {
 												deltas[i].accept(description.getVisitor());
 											}
 										}
 										if (!projects[i].isAccessible() || (deltas[i] != null && deltas[i].getKind() == IResourceDelta.REMOVED)) {
 											if (_debugIndexCreation) {
 												Logger.log(Logger.INFO_DEBUG, "TaglibIndex noticed " + projects[i].getName() + " was removed or is no longer accessible"); //$NON-NLS-1$ //$NON-NLS-2$
 											}
 											ProjectDescription description = (ProjectDescription) fProjectDescriptions.remove(projects[i]);
 											if (description != null) {
 												if (_debugIndexCreation) {
 													Logger.log(Logger.INFO_DEBUG, "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); //$NON-NLS-1$
 						}
 					}
 				}
 			}
 			finally {
 				LOCK.release();
 			}
 		}
 	}

 	static final boolean _debugChangeListener = false;

 	static boolean _debugEvents = "true".equalsIgnoreCase(Platform.getDebugOption("org.eclipse.jst.jsp.core/taglib/events")); //$NON-NLS-1$ //$NON-NLS-2$

 	static boolean _debugIndexCreation = "true".equalsIgnoreCase(Platform.getDebugOption("org.eclipse.jst.jsp.core/taglib/indexcreation")); //$NON-NLS-1$ //$NON-NLS-2$

 	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 boolean ENABLED = false;
 	static ILock LOCK = null;

 	/**
 	 * NOT API.
 	 *
 	 * @param listener
 	 *            the listener to be added
 	 */
 	public static void addTaglibIndexListener(ITaglibIndexListener listener) {
 		try {
 			LOCK.acquire();
 			_instance.internalAddTaglibIndexListener(listener);
 		}
 		finally {
 			LOCK.release();
 		}
 	}

 	static void fireTaglibRecordEvent(ITaglibRecordEvent event) {
 		if (_debugEvents) {
 			Logger.log(Logger.INFO_DEBUG, "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());
 				}
 			}
 		}
 	}

 	/**
 	 * Finds all of the visible ITaglibRecords for the given path in the
 	 * workspace. Taglib mappings from web.xml files are only visible to paths
 	 * within the web.xml's corresponding web content folder.
 	 * <p>
 	 * Values defined within the XML Catalog will not be returned.
 	 * </p>
 	 *
 	 * @param fullPath -
 	 *            a path within the workspace
 	 * @return All of the visible ITaglibRecords from the given path.
 	 */
 	public static ITaglibRecord[] getAvailableTaglibRecords(IPath fullPath) {
 		ITaglibRecord[] records = _instance.internalGetAvailableTaglibRecords(fullPath);
 		return records;
 	}

 	/**
 	 * Returns the IPath considered to be the web-app root for the given path.
 	 * All resolution from the given path beginning with '/' will be relative
 	 * to the computed web-app root.
 	 *
 	 * @deprecated - is not correct in flexible projects
 	 * @param path -
 	 *            a path under the web-app root
 	 * @return the IPath considered to be the web-app's root for the given
 	 *         path
 	 */
 	public static IPath getContextRoot(IPath path) {
 		try {
 			LOCK.acquire();
 			return _instance.internalGetContextRoot(path);
 		}
 		finally {
 			LOCK.release();
 		}
 	}

 	/**
 	 * NOT API.
 	 *
 	 * @param listener
 	 *            the listener to be removed
 	 */
 	public static void removeTaglibIndexListener(ITaglibIndexListener listener) {
 		try {
 			LOCK.acquire();
 			_instance.internalRemoveTaglibIndexListener(listener);
 		}
 		finally {
 			LOCK.release();
 		}
 	}

 	/**
 	 * Finds a matching ITaglibRecord given the reference. Typically the
 	 * result will have to be cast to a subiinterface of ITaglibRecord.
 	 *
 	 * @param basePath -
 	 *            the workspace-relative path for IResources, full filesystem
 	 *            path otherwise
 	 * @param reference -
 	 *            the URI to lookup, for example the uri value from a taglib
 	 *            directive
 	 * @param crossProjects -
 	 *            whether to search across projects (currently ignored)
 	 *
 	 * @return a visible ITaglibRecord or null if the reference points to no
 	 *         known tag library descriptor
 	 *
 	 * @See ITaglibRecord
 	 */
 	public static ITaglibRecord resolve(String basePath, String reference, boolean crossProjects) {
 		ITaglibRecord result = null;
 		try {
 			LOCK.acquire();
 			result = _instance.internalResolve(basePath, reference, crossProjects);
 		}
 		finally {
 			LOCK.release();
 		}
 		if (_debugResolution) {
 			if (result == null) {
 				Logger.log(Logger.INFO_DEBUG, "TaglibIndex could not resolve \"" + reference + "\" from " + basePath); //$NON-NLS-1$ //$NON-NLS-2$
 			}
 			else {
 				switch (result.getRecordType()) {
 					case (ITaglibRecord.TLD) : {
 						ITLDRecord record = (ITLDRecord) result;
 						Logger.log(Logger.INFO_DEBUG, "TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getPath()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 					}
 						break;
 					case (ITaglibRecord.JAR) : {
 						IJarRecord record = (IJarRecord) result;
 						Logger.log(Logger.INFO_DEBUG, "TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getLocation()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 					}
 						break;
 					case (ITaglibRecord.TAGDIR) : {
 					}
 						break;
 					case (ITaglibRecord.URL) : {
 						IURLRecord record = (IURLRecord) result;
 						Logger.log(Logger.INFO_DEBUG, "TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getURL()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 					}
 						break;
 				}
 			}
 		}
 		return result;
 	}

 	/**
 	 * Instructs the index to stop listening for resource and classpath
 	 * changes, and to forget all information about the workspace.
 	 */
 	public static synchronized void shutdown() {
 		if (_instance != null) {
 			_instance.stop();
 		}
 		_instance = null;
 	}

 	/**
 	 * Instructs the index to begin listening for resource and classpath
 	 * changes.
 	 */
 	public static synchronized void startup() {
 		ENABLED = !"false".equalsIgnoreCase(System.getProperty(TaglibIndex.class.getName())); //$NON-NLS-1$
 		_instance = new TaglibIndex();
 	}

 	private ClasspathChangeListener fClasspathChangeListener = null;

 	Map fProjectDescriptions;

 	private ResourceChangeListener fResourceChangeListener;

 	private ITaglibIndexListener[] fTaglibIndexListeners = null;
 	/** symbolic name for OSGI framework */
 	private final String OSGI_FRAMEWORK_ID = "org.eclipse.osgi"; //$NON-NLS-1$

 	private TaglibIndex() {
 		super();
 		fResourceChangeListener = new ResourceChangeListener();
 		fClasspathChangeListener = new ClasspathChangeListener();
 		if (ENABLED) {
 			ResourcesPlugin.getWorkspace().addResourceChangeListener(fResourceChangeListener, IResourceChangeEvent.POST_CHANGE);
 			JavaCore.addElementChangedListener(fClasspathChangeListener);
 		}
 		LOCK = Platform.getJobManager().newLock();
 		fProjectDescriptions = new Hashtable();
 	}

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

 	/**
 	 * A check to see if the OSGI framework is shutting down.
 	 *
 	 * @return true if the System Bundle is stopped (ie. the framework is
 	 *         shutting down)
 	 */
 	boolean frameworkIsShuttingDown() {
 		// in the Framework class there's a note:
 		// set the state of the System Bundle to STOPPING.
 		// this must be done first according to section 4.19.2 from the OSGi
 		// R3 spec.
 		boolean shuttingDown = !Platform.isRunning() || Platform.getBundle(OSGI_FRAMEWORK_ID).getState() == Bundle.STOPPING;
 		return shuttingDown;
 	}

 	ProjectDescription getDescription(IProject project) {
 		ProjectDescription description = null;
 		description = (ProjectDescription) fProjectDescriptions.get(project);
 		return description;
 	}

 	private 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 path) {
 		ITaglibRecord[] records = new ITaglibRecord[0];
 		if (path.segmentCount() > 0) {
 			IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject(path.segment(0));
 			ProjectDescription description = createDescription(project);
 			List availableRecords = description.getAvailableTaglibRecords(path);
 			records = (ITaglibRecord[]) availableRecords.toArray(records);
 		}
 		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 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 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, final String reference, boolean crossProjects) {
 		IProject project = null;
 		ITaglibRecord resolved = null;

 		IFile baseResource = FileBuffers.getWorkspaceFileAtLocation(new Path(basePath));
 		if (baseResource == null) {
 			/*
 			 * https://bugs.eclipse.org/bugs/show_bug.cgi?id=116529
 			 *
 			 * This method produces a less accurate result, but doesn't
 			 * require that the file exist yet.
 			 */
 			IFile[] files = ResourcesPlugin.getWorkspace().getRoot().findFilesForLocation(new Path(basePath));
 			if (files.length > 0)
 				baseResource = files[0];
 		}
 		if (baseResource != null) {
 			project = baseResource.getProject();
 			ProjectDescription description = createDescription(project);
 			resolved = description.resolve(basePath, reference);
 		}
 		return resolved;
 	}

 	boolean isIndexAvailable() {
 		return _instance != null && ENABLED;
 	}

 	private void stop() {
 		ResourcesPlugin.getWorkspace().removeResourceChangeListener(fResourceChangeListener);
 		JavaCore.removeElementChangedListener(fClasspathChangeListener);
 		fProjectDescriptions.clear();
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2005 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.taglib;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Hashtable;
	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.core.runtime.jobs.ILock;
	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.utils.StringUtils;
	import org.osgi.framework.Bundle;

	/**
	* A non-extendable index manager for taglibs similar to the previous J2EE
	* ITaglibRegistry but lacking any ties to project natures. Each record
	* returned from the index represents a single tag library descriptor.
	*
	* 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. The record's contents should be examined
	* for any further information.
	*
	* @since 1.0
	*/
	public final class TaglibIndex {
	class ClasspathChangeListener implements IElementChangedListener {
	Stack classpathStack = new Stack();
	List projectsIndexed = new ArrayList(1);

	public void elementChanged(ElementChangedEvent event) {
	if (!isIndexAvailable())
	return;
	try {
	LOCK.acquire();
	classpathStack.clear();
	projectsIndexed.clear();
	elementChanged(event.getDelta());
	}
	finally {
	LOCK.release();
	}
	}

	private void elementChanged(IJavaElementDelta delta) {
	if (frameworkIsShuttingDown())
	return;

	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) {
	if (frameworkIsShuttingDown())
	return;

	/*
	* Loops in the build paths could cause us to pop more than we
	* push
	*/
	if (classpathStack.contains(project.getElementName()))
	return;

	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)) {
	ProjectDescription description = getDescription((IProject) resource);
	if (description != null && !frameworkIsShuttingDown()) {
	projectsIndexed.add(resource);
	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()) && !frameworkIsShuttingDown()) {
	handleClasspathChange(otherProject);
	}
	}
	}
	catch (JavaModelException e) {
	}
	classpathStack.pop();

	}
	}

	class ResourceChangeListener implements IResourceChangeListener {
	public void resourceChanged(IResourceChangeEvent event) {
	if (!isIndexAvailable())
	return;
	try {
	LOCK.acquire();
	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) {
	Logger.log(Logger.INFO_DEBUG, "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) {
	Logger.log(Logger.INFO_DEBUG, "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 = getDescription(projects[i]);
	if (description != null && !frameworkIsShuttingDown()) {
	deltas[i].accept(description.getVisitor());
	}
	}
	if (!projects[i].isAccessible() \|\| (deltas[i] != null && deltas[i].getKind() == IResourceDelta.REMOVED)) {
	if (_debugIndexCreation) {
	Logger.log(Logger.INFO_DEBUG, "TaglibIndex noticed " + projects[i].getName() + " was removed or is no longer accessible"); //$NON-NLS-1$ //$NON-NLS-2$
	}
	ProjectDescription description = (ProjectDescription) fProjectDescriptions.remove(projects[i]);
	if (description != null) {
	if (_debugIndexCreation) {
	Logger.log(Logger.INFO_DEBUG, "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); //$NON-NLS-1$
	}
	}
	}
	}
	finally {
	LOCK.release();
	}
	}
	}

	static final boolean _debugChangeListener = false;

	static boolean _debugEvents = "true".equalsIgnoreCase(Platform.getDebugOption("org.eclipse.jst.jsp.core/taglib/events")); //$NON-NLS-1$ //$NON-NLS-2$

	static boolean _debugIndexCreation = "true".equalsIgnoreCase(Platform.getDebugOption("org.eclipse.jst.jsp.core/taglib/indexcreation")); //$NON-NLS-1$ //$NON-NLS-2$

	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 boolean ENABLED = false;
	static ILock LOCK = null;

	/**
	* NOT API.
	*
	* @param listener
	* the listener to be added
	*/
	public static void addTaglibIndexListener(ITaglibIndexListener listener) {
	try {
	LOCK.acquire();
	_instance.internalAddTaglibIndexListener(listener);
	}
	finally {
	LOCK.release();
	}
	}

	static void fireTaglibRecordEvent(ITaglibRecordEvent event) {
	if (_debugEvents) {
	Logger.log(Logger.INFO_DEBUG, "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());
	}
	}
	}
	}

	/**
	* Finds all of the visible ITaglibRecords for the given path in the
	* workspace. Taglib mappings from web.xml files are only visible to paths
	* within the web.xml's corresponding web content folder.
	* <p>
	* Values defined within the XML Catalog will not be returned.
	* </p>
	*
	* @param fullPath -
	* a path within the workspace
	* @return All of the visible ITaglibRecords from the given path.
	*/
	public static ITaglibRecord[] getAvailableTaglibRecords(IPath fullPath) {
	ITaglibRecord[] records = _instance.internalGetAvailableTaglibRecords(fullPath);
	return records;
	}

	/**
	* Returns the IPath considered to be the web-app root for the given path.
	* All resolution from the given path beginning with '/' will be relative
	* to the computed web-app root.
	*
	* @deprecated - is not correct in flexible projects
	* @param path -
	* a path under the web-app root
	* @return the IPath considered to be the web-app's root for the given
	* path
	*/
	public static IPath getContextRoot(IPath path) {
	try {
	LOCK.acquire();
	return _instance.internalGetContextRoot(path);
	}
	finally {
	LOCK.release();
	}
	}

	/**
	* NOT API.
	*
	* @param listener
	* the listener to be removed
	*/
	public static void removeTaglibIndexListener(ITaglibIndexListener listener) {
	try {
	LOCK.acquire();
	_instance.internalRemoveTaglibIndexListener(listener);
	}
	finally {
	LOCK.release();
	}
	}

	/**
	* Finds a matching ITaglibRecord given the reference. Typically the
	* result will have to be cast to a subiinterface of ITaglibRecord.
	*
	* @param basePath -
	* the workspace-relative path for IResources, full filesystem
	* path otherwise
	* @param reference -
	* the URI to lookup, for example the uri value from a taglib
	* directive
	* @param crossProjects -
	* whether to search across projects (currently ignored)
	*
	* @return a visible ITaglibRecord or null if the reference points to no
	* known tag library descriptor
	*
	* @See ITaglibRecord
	*/
	public static ITaglibRecord resolve(String basePath, String reference, boolean crossProjects) {
	ITaglibRecord result = null;
	try {
	LOCK.acquire();
	result = _instance.internalResolve(basePath, reference, crossProjects);
	}
	finally {
	LOCK.release();
	}
	if (_debugResolution) {
	if (result == null) {
	Logger.log(Logger.INFO_DEBUG, "TaglibIndex could not resolve \"" + reference + "\" from " + basePath); //$NON-NLS-1$ //$NON-NLS-2$
	}
	else {
	switch (result.getRecordType()) {
	case (ITaglibRecord.TLD) : {
	ITLDRecord record = (ITLDRecord) result;
	Logger.log(Logger.INFO_DEBUG, "TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getPath()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
	}
	break;
	case (ITaglibRecord.JAR) : {
	IJarRecord record = (IJarRecord) result;
	Logger.log(Logger.INFO_DEBUG, "TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getLocation()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
	}
	break;
	case (ITaglibRecord.TAGDIR) : {
	}
	break;
	case (ITaglibRecord.URL) : {
	IURLRecord record = (IURLRecord) result;
	Logger.log(Logger.INFO_DEBUG, "TaglibIndex resolved " + basePath + ":" + reference + " = " + record.getURL()); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
	}
	break;
	}
	}
	}
	return result;
	}

	/**
	* Instructs the index to stop listening for resource and classpath
	* changes, and to forget all information about the workspace.
	*/
	public static synchronized void shutdown() {
	if (_instance != null) {
	_instance.stop();
	}
	_instance = null;
	}

	/**
	* Instructs the index to begin listening for resource and classpath
	* changes.
	*/
	public static synchronized void startup() {
	ENABLED = !"false".equalsIgnoreCase(System.getProperty(TaglibIndex.class.getName())); //$NON-NLS-1$
	_instance = new TaglibIndex();
	}

	private ClasspathChangeListener fClasspathChangeListener = null;

	Map fProjectDescriptions;

	private ResourceChangeListener fResourceChangeListener;

	private ITaglibIndexListener[] fTaglibIndexListeners = null;
	/** symbolic name for OSGI framework */
	private final String OSGI_FRAMEWORK_ID = "org.eclipse.osgi"; //$NON-NLS-1$

	private TaglibIndex() {
	super();
	fResourceChangeListener = new ResourceChangeListener();
	fClasspathChangeListener = new ClasspathChangeListener();
	if (ENABLED) {
	ResourcesPlugin.getWorkspace().addResourceChangeListener(fResourceChangeListener, IResourceChangeEvent.POST_CHANGE);
	JavaCore.addElementChangedListener(fClasspathChangeListener);
	}
	LOCK = Platform.getJobManager().newLock();
	fProjectDescriptions = new Hashtable();
	}

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

	/**
	* A check to see if the OSGI framework is shutting down.
	*
	* @return true if the System Bundle is stopped (ie. the framework is
	* shutting down)
	*/
	boolean frameworkIsShuttingDown() {
	// in the Framework class there's a note:
	// set the state of the System Bundle to STOPPING.
	// this must be done first according to section 4.19.2 from the OSGi
	// R3 spec.
	boolean shuttingDown = !Platform.isRunning() \|\| Platform.getBundle(OSGI_FRAMEWORK_ID).getState() == Bundle.STOPPING;
	return shuttingDown;
	}

	ProjectDescription getDescription(IProject project) {
	ProjectDescription description = null;
	description = (ProjectDescription) fProjectDescriptions.get(project);
	return description;
	}

	private 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 path) {
	ITaglibRecord[] records = new ITaglibRecord[0];
	if (path.segmentCount() > 0) {
	IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject(path.segment(0));
	ProjectDescription description = createDescription(project);
	List availableRecords = description.getAvailableTaglibRecords(path);
	records = (ITaglibRecord[]) availableRecords.toArray(records);
	}
	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 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 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, final String reference, boolean crossProjects) {
	IProject project = null;
	ITaglibRecord resolved = null;

	IFile baseResource = FileBuffers.getWorkspaceFileAtLocation(new Path(basePath));
	if (baseResource == null) {
	/*
	* https://bugs.eclipse.org/bugs/show_bug.cgi?id=116529
	*
	* This method produces a less accurate result, but doesn't
	* require that the file exist yet.
	*/
	IFile[] files = ResourcesPlugin.getWorkspace().getRoot().findFilesForLocation(new Path(basePath));
	if (files.length > 0)
	baseResource = files[0];
	}
	if (baseResource != null) {
	project = baseResource.getProject();
	ProjectDescription description = createDescription(project);
	resolved = description.resolve(basePath, reference);
	}
	return resolved;
	}

	boolean isIndexAvailable() {
	return _instance != null && ENABLED;
	}

	private void stop() {
	ResourcesPlugin.getWorkspace().removeResourceChangeListener(fResourceChangeListener);
	JavaCore.removeElementChangedListener(fClasspathChangeListener);
	fProjectDescriptions.clear();
	}
	}