src/java/org/eclipse/jetty/webapp/TagLibConfiguration.java - platform/external/jetty - Git at Google

 //
 //  ========================================================================
 //  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
 //  ------------------------------------------------------------------------
 //  All rights reserved. This program and the accompanying materials
 //  are made available under the terms of the Eclipse Public License v1.0
 //  and Apache License v2.0 which accompanies this distribution.
 //
 //      The Eclipse Public License is available at
 //      http://www.eclipse.org/legal/epl-v10.html
 //
 //      The Apache License v2.0 is available at
 //      http://www.opensource.org/licenses/apache2.0.php
 //
 //  You may elect to redistribute this code under either of these licenses.
 //  ========================================================================
 //

 package org.eclipse.jetty.webapp;

 import java.io.IOException;
 import java.net.URI;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.EventListener;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;

 import javax.servlet.Servlet;
 import javax.servlet.ServletContextEvent;
 import javax.servlet.ServletContextListener;

 import org.eclipse.jetty.util.Loader;
 import org.eclipse.jetty.util.log.Log;
 import org.eclipse.jetty.util.log.Logger;
 import org.eclipse.jetty.util.resource.Resource;
 import org.eclipse.jetty.xml.XmlParser;

 /* ------------------------------------------------------------ */
 /** TagLibConfiguration.
  *
  * The class searches for TLD descriptors found in web.xml, in WEB-INF/*.tld files of the web app
  * or *.tld files within jars found in WEB-INF/lib of the webapp.   Any listeners defined in these
  * tld's are added to the context.
  *
  * &lt;bile&gt;This is total rubbish special case for JSPs! If there was a general use-case for web app
  * frameworks to register listeners directly, then a generic mechanism could have been added to the servlet
  * spec.  Instead some special purpose JSP support is required that breaks all sorts of encapsulation rules as
  * the servlet container must go searching for and then parsing the descriptors for one particular framework.
  * It only appears to be used by JSF, which is being developed by the same developer who implemented this
  * feature in the first place!
  * &lt;/bile&gt;
  *
  *
  * Note- this has been superceded by the new TldScanner in jasper which uses ServletContainerInitializer to
  * find all the listeners in tag libs and register them.
  */
 public class TagLibConfiguration extends AbstractConfiguration
 {
     private static final Logger LOG = Log.getLogger(TagLibConfiguration.class);

     public static final String TLD_RESOURCES = "org.eclipse.jetty.tlds";


     /**
      * TagLibListener
      *
      * A listener that does the job of finding .tld files that contain
      * (other) listeners that need to be called by the servlet container.
      *
      * This implementation is necessitated by the fact that it is only
      * after all the Configuration classes have run that we will
      * parse web.xml/fragments etc and thus find tlds mentioned therein.
      *
      * Note: TagLibConfiguration is not used in jetty-8 as jasper (JSP engine)
      * uses the new TldScanner class - a ServletContainerInitializer from
      * Servlet Spec 3 - to find all listeners in taglibs and register them
      * with the servlet container.
      */
     public  class TagLibListener implements ServletContextListener {
         private List<EventListener> _tldListeners;
         private WebAppContext _context;

         public TagLibListener (WebAppContext context) {
             _context = context;
         }

         public void contextDestroyed(ServletContextEvent sce)
         {
             if (_tldListeners == null)
                 return;

             for (int i=_tldListeners.size()-1; i>=0; i--) {
                 EventListener l = _tldListeners.get(i);
                 if (l instanceof ServletContextListener) {
                     ((ServletContextListener)l).contextDestroyed(sce);
                 }
             }
         }

         public void contextInitialized(ServletContextEvent sce)
         {
             try
             {
                 //For jasper 2.1:
                 //Get the system classpath tlds and tell jasper about them, if jasper is on the classpath
                 try
                 {

                     ClassLoader loader = _context.getClassLoader();
                     if (loader == null || loader.getParent() == null)
                         loader = getClass().getClassLoader();
                     else
                         loader = loader.getParent();
                     Class<?> clazz = loader.loadClass("org.apache.jasper.compiler.TldLocationsCache");
                     assert clazz!=null;
                     Collection<Resource> tld_resources = (Collection<Resource>)_context.getAttribute(TLD_RESOURCES);

                     Map<URI, List<String>> tldMap = new HashMap<URI, List<String>>();

                     if (tld_resources != null)
                     {
                         //get the jar file names of the files
                         for (Resource r:tld_resources)
                         {
                             Resource jarResource = extractJarResource(r);
                             //jasper is happy with an empty list of tlds
                             if (!tldMap.containsKey(jarResource.getURI()))
                                 tldMap.put(jarResource.getURI(), null);

                         }
                         //set the magic context attribute that tells jasper about the system tlds
                         sce.getServletContext().setAttribute("com.sun.appserv.tld.map", tldMap);
                     }
                 }
                 catch (ClassNotFoundException e)
                 {
                     LOG.ignore(e);
                 }

                 //find the tld files and parse them to get out their
                 //listeners
                 Set<Resource> tlds = findTldResources();
                 List<TldDescriptor> descriptors = parseTlds(tlds);
                 processTlds(descriptors);

                 if (_tldListeners == null)
                     return;

                 //call the listeners that are ServletContextListeners, put the
                 //rest into the context's list of listeners to call at the appropriate
                 //moment
                 for (EventListener l:_tldListeners) {
                     if (l instanceof ServletContextListener) {
                         ((ServletContextListener)l).contextInitialized(sce);
                     } else {
                         _context.addEventListener(l);
                     }
                 }

             }
             catch (Exception e) {
                 LOG.warn(e);
             }
         }


         private Resource extractJarResource (Resource r)
         {
             if (r == null)
                 return null;

             try
             {
                 String url = r.getURI().toURL().toString();
                 int idx = url.lastIndexOf("!/");
                 if (idx >= 0)
                     url = url.substring(0, idx);
                 if (url.startsWith("jar:"))
                     url = url.substring(4);
                 return Resource.newResource(url);
             }
             catch (IOException e)
             {
                 LOG.warn(e);
                 return null;
             }
         }

         /**
          * Find all the locations that can harbour tld files that may contain
          * a listener which the web container is supposed to instantiate and
          * call.
          *
          * @return
          * @throws IOException
          */
         private Set<Resource> findTldResources () throws IOException {

             Set<Resource> tlds = new HashSet<Resource>();

             // Find tld's from web.xml
             // When web.xml was processed, it should have created aliases for all TLDs.  So search resources aliases
             // for aliases ending in tld
             if (_context.getResourceAliases()!=null &&
                     _context.getBaseResource()!=null &&
                     _context.getBaseResource().exists())
             {
                 Iterator<String> iter=_context.getResourceAliases().values().iterator();
                 while(iter.hasNext())
                 {
                     String location = iter.next();
                     if (location!=null && location.toLowerCase(Locale.ENGLISH).endsWith(".tld"))
                     {
                         if (!location.startsWith("/"))
                             location="/WEB-INF/"+location;
                         Resource l=_context.getBaseResource().addPath(location);
                         tlds.add(l);
                     }
                 }
             }

             // Look for any tlds in WEB-INF directly.
             Resource web_inf = _context.getWebInf();
             if (web_inf!=null)
             {
                 String[] contents = web_inf.list();
                 for (int i=0;contents!=null && i<contents.length;i++)
                 {
                     if (contents[i]!=null && contents[i].toLowerCase(Locale.ENGLISH).endsWith(".tld"))
                     {
                         Resource l=web_inf.addPath(contents[i]);
                         tlds.add(l);
                     }
                 }
             }

             //Look for tlds in common location of WEB-INF/tlds
             if (web_inf != null) {
                 Resource web_inf_tlds = _context.getWebInf().addPath("/tlds/");
                 if (web_inf_tlds.exists() && web_inf_tlds.isDirectory()) {
                     String[] contents = web_inf_tlds.list();
                     for (int i=0;contents!=null && i<contents.length;i++)
                     {
                         if (contents[i]!=null && contents[i].toLowerCase(Locale.ENGLISH).endsWith(".tld"))
                         {
                             Resource l=web_inf_tlds.addPath(contents[i]);
                             tlds.add(l);
                         }
                     }
                 }
             }

             // Add in tlds found in META-INF of jars. The jars that will be scanned are controlled by
             // the patterns defined in the context attributes: org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern,
             // and org.eclipse.jetty.server.webapp.WebInfIncludeJarPattern
             @SuppressWarnings("unchecked")
             Collection<Resource> tld_resources=(Collection<Resource>)_context.getAttribute(TLD_RESOURCES);
             if (tld_resources!=null)
                 tlds.addAll(tld_resources);

             return tlds;
         }


         /**
          * Parse xml into in-memory tree
          * @param tlds
          * @return
          */
         private List<TldDescriptor> parseTlds (Set<Resource> tlds) {
             List<TldDescriptor> descriptors = new ArrayList<TldDescriptor>();

             Resource tld = null;
             Iterator<Resource> iter = tlds.iterator();
             while (iter.hasNext())
             {
                 try
                 {
                     tld = iter.next();
                     if (LOG.isDebugEnabled()) LOG.debug("TLD="+tld);

                     TldDescriptor d = new TldDescriptor(tld);
                     d.parse();
                     descriptors.add(d);
                 }
                 catch(Exception e)
                 {
                     LOG.warn("Unable to parse TLD: " + tld,e);
                 }
             }
             return descriptors;
         }


         /**
          * Create listeners from the parsed tld trees
          * @param descriptors
          * @throws Exception
          */
         private void processTlds (List<TldDescriptor> descriptors) throws Exception {

             TldProcessor processor = new TldProcessor();
             for (TldDescriptor d:descriptors)
                 processor.process(_context, d);

             _tldListeners = new ArrayList<EventListener>(processor.getListeners());
         }
     }


     /**
      * TldDescriptor
      *
      *
      */
     public static class TldDescriptor extends Descriptor
     {
         protected static XmlParser __parserSingleton;

         public TldDescriptor(Resource xml)
         {
             super(xml);
         }

         @Override
         public void ensureParser() throws ClassNotFoundException
         {
            if (__parserSingleton == null)
                __parserSingleton = newParser();
             _parser = __parserSingleton;
         }

         @Override
         public XmlParser newParser() throws ClassNotFoundException
         {
             // Create a TLD parser
             XmlParser parser = new XmlParser(false);

             URL taglib11=null;
             URL taglib12=null;
             URL taglib20=null;
             URL taglib21=null;

             try
             {
                 Class<?> jsp_page = Loader.loadClass(WebXmlConfiguration.class,"javax.servlet.jsp.JspPage");
                 taglib11=jsp_page.getResource("javax/servlet/jsp/resources/web-jsptaglibrary_1_1.dtd");
                 taglib12=jsp_page.getResource("javax/servlet/jsp/resources/web-jsptaglibrary_1_2.dtd");
                 taglib20=jsp_page.getResource("javax/servlet/jsp/resources/web-jsptaglibrary_2_0.xsd");
                 taglib21=jsp_page.getResource("javax/servlet/jsp/resources/web-jsptaglibrary_2_1.xsd");
             }
             catch(Exception e)
             {
                 LOG.ignore(e);
             }
             finally
             {
                 if(taglib11==null)
                     taglib11=Loader.getResource(Servlet.class,"javax/servlet/jsp/resources/web-jsptaglibrary_1_1.dtd",true);
                 if(taglib12==null)
                     taglib12=Loader.getResource(Servlet.class,"javax/servlet/jsp/resources/web-jsptaglibrary_1_2.dtd",true);
                 if(taglib20==null)
                     taglib20=Loader.getResource(Servlet.class,"javax/servlet/jsp/resources/web-jsptaglibrary_2_0.xsd",true);
                 if(taglib21==null)
                     taglib21=Loader.getResource(Servlet.class,"javax/servlet/jsp/resources/web-jsptaglibrary_2_1.xsd",true);
             }


             if(taglib11!=null)
             {
                 redirect(parser, "web-jsptaglib_1_1.dtd",taglib11);
                 redirect(parser, "web-jsptaglibrary_1_1.dtd",taglib11);
             }
             if(taglib12!=null)
             {
                 redirect(parser, "web-jsptaglib_1_2.dtd",taglib12);
                 redirect(parser, "web-jsptaglibrary_1_2.dtd",taglib12);
             }
             if(taglib20!=null)
             {
                 redirect(parser, "web-jsptaglib_2_0.xsd",taglib20);
                 redirect(parser, "web-jsptaglibrary_2_0.xsd",taglib20);
             }
             if(taglib21!=null)
             {
                 redirect(parser, "web-jsptaglib_2_1.xsd",taglib21);
                 redirect(parser, "web-jsptaglibrary_2_1.xsd",taglib21);
             }

             parser.setXpath("/taglib/listener/listener-class");
             return parser;
         }

         public void parse ()
         throws Exception
         {
             ensureParser();
             try
             {
                 //xerces on apple appears to sometimes close the zip file instead
                 //of the inputstream, so try opening the input stream, but if
                 //that doesn't work, fallback to opening a new url
                 _root = _parser.parse(_xml.getInputStream());
             }
             catch (Exception e)
             {
                 _root = _parser.parse(_xml.getURL().toString());
             }

             if (_root==null)
             {
                 LOG.warn("No TLD root in {}",_xml);
             }
         }
     }


     /**
      * TldProcessor
      *
      * Process TldDescriptors representing tag libs to find listeners.
      */
     public class TldProcessor extends IterativeDescriptorProcessor
     {
         public static final String TAGLIB_PROCESSOR = "org.eclipse.jetty.tagLibProcessor";
         XmlParser _parser;
         List<XmlParser.Node> _roots = new ArrayList<XmlParser.Node>();
         List<EventListener> _listeners;


         public TldProcessor ()
         throws Exception
         {
             _listeners = new ArrayList<EventListener>();
             registerVisitor("listener", this.getClass().getDeclaredMethod("visitListener", __signature));
         }


         public void visitListener (WebAppContext context, Descriptor descriptor, XmlParser.Node node)
         {
             String className=node.getString("listener-class",false,true);
             if (LOG.isDebugEnabled())
                 LOG.debug("listener="+className);

             try
             {
                 Class<?> listenerClass = context.loadClass(className);
                 EventListener l = (EventListener)listenerClass.newInstance();
                 _listeners.add(l);
             }
             catch(Exception e)
             {
                 LOG.warn("Could not instantiate listener "+className+": "+e);
                 LOG.debug(e);
             }
             catch(Error e)
             {
                 LOG.warn("Could not instantiate listener "+className+": "+e);
                 LOG.debug(e);
             }

         }

         @Override
         public void end(WebAppContext context, Descriptor descriptor)
         {
         }

         @Override
         public void start(WebAppContext context, Descriptor descriptor)
         {
         }

         public List<EventListener> getListeners() {
             return _listeners;
         }
     }


     @Override
     public void preConfigure(WebAppContext context) throws Exception
     {
         try
         {
             Class<?> jsp_page = Loader.loadClass(WebXmlConfiguration.class,"javax.servlet.jsp.JspPage");
         }
         catch (Exception e)
         {
             //no jsp available, don't parse TLDs
             return;
         }

         TagLibListener tagLibListener = new TagLibListener(context);
         context.addEventListener(tagLibListener);
     }


     @Override
     public void configure (WebAppContext context) throws Exception
     {
     }

     @Override
     public void postConfigure(WebAppContext context) throws Exception
     {
     }


     @Override
     public void cloneConfigure(WebAppContext template, WebAppContext context) throws Exception
     {
     }


     @Override
     public void deconfigure(WebAppContext context) throws Exception
     {
     }
 }
	//
	// ========================================================================
	// Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
	// ------------------------------------------------------------------------
	// All rights reserved. This program and the accompanying materials
	// are made available under the terms of the Eclipse Public License v1.0
	// and Apache License v2.0 which accompanies this distribution.
	//
	// The Eclipse Public License is available at
	// http://www.eclipse.org/legal/epl-v10.html
	//
	// The Apache License v2.0 is available at
	// http://www.opensource.org/licenses/apache2.0.php
	//
	// You may elect to redistribute this code under either of these licenses.
	// ========================================================================
	//

	package org.eclipse.jetty.webapp;

	import java.io.IOException;
	import java.net.URI;
	import java.net.URL;
	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.EventListener;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Locale;
	import java.util.Map;
	import java.util.Set;

	import javax.servlet.Servlet;
	import javax.servlet.ServletContextEvent;
	import javax.servlet.ServletContextListener;

	import org.eclipse.jetty.util.Loader;
	import org.eclipse.jetty.util.log.Log;
	import org.eclipse.jetty.util.log.Logger;
	import org.eclipse.jetty.util.resource.Resource;
	import org.eclipse.jetty.xml.XmlParser;

	/* ------------------------------------------------------------ */
	/** TagLibConfiguration.
	*
	* The class searches for TLD descriptors found in web.xml, in WEB-INF/*.tld files of the web app
	* or *.tld files within jars found in WEB-INF/lib of the webapp. Any listeners defined in these
	* tld's are added to the context.
	*
	* <bile>This is total rubbish special case for JSPs! If there was a general use-case for web app
	* frameworks to register listeners directly, then a generic mechanism could have been added to the servlet
	* spec. Instead some special purpose JSP support is required that breaks all sorts of encapsulation rules as
	* the servlet container must go searching for and then parsing the descriptors for one particular framework.
	* It only appears to be used by JSF, which is being developed by the same developer who implemented this
	* feature in the first place!
	* </bile>
	*
	*
	* Note- this has been superceded by the new TldScanner in jasper which uses ServletContainerInitializer to
	* find all the listeners in tag libs and register them.
	*/
	public class TagLibConfiguration extends AbstractConfiguration
	{
	private static final Logger LOG = Log.getLogger(TagLibConfiguration.class);

	public static final String TLD_RESOURCES = "org.eclipse.jetty.tlds";


	/**
	* TagLibListener
	*
	* A listener that does the job of finding .tld files that contain
	* (other) listeners that need to be called by the servlet container.
	*
	* This implementation is necessitated by the fact that it is only
	* after all the Configuration classes have run that we will
	* parse web.xml/fragments etc and thus find tlds mentioned therein.
	*
	* Note: TagLibConfiguration is not used in jetty-8 as jasper (JSP engine)
	* uses the new TldScanner class - a ServletContainerInitializer from
	* Servlet Spec 3 - to find all listeners in taglibs and register them
	* with the servlet container.
	*/
	public class TagLibListener implements ServletContextListener {
	private List<EventListener> _tldListeners;
	private WebAppContext _context;

	public TagLibListener (WebAppContext context) {
	_context = context;
	}

	public void contextDestroyed(ServletContextEvent sce)
	{
	if (_tldListeners == null)
	return;

	for (int i=_tldListeners.size()-1; i>=0; i--) {
	EventListener l = _tldListeners.get(i);
	if (l instanceof ServletContextListener) {
	((ServletContextListener)l).contextDestroyed(sce);
	}
	}
	}

	public void contextInitialized(ServletContextEvent sce)
	{
	try
	{
	//For jasper 2.1:
	//Get the system classpath tlds and tell jasper about them, if jasper is on the classpath
	try
	{

	ClassLoader loader = _context.getClassLoader();
	if (loader == null \|\| loader.getParent() == null)
	loader = getClass().getClassLoader();
	else
	loader = loader.getParent();
	Class<?> clazz = loader.loadClass("org.apache.jasper.compiler.TldLocationsCache");
	assert clazz!=null;
	Collection<Resource> tld_resources = (Collection<Resource>)_context.getAttribute(TLD_RESOURCES);

	Map<URI, List<String>> tldMap = new HashMap<URI, List<String>>();

	if (tld_resources != null)
	{
	//get the jar file names of the files
	for (Resource r:tld_resources)
	{
	Resource jarResource = extractJarResource(r);
	//jasper is happy with an empty list of tlds
	if (!tldMap.containsKey(jarResource.getURI()))
	tldMap.put(jarResource.getURI(), null);

	}
	//set the magic context attribute that tells jasper about the system tlds
	sce.getServletContext().setAttribute("com.sun.appserv.tld.map", tldMap);
	}
	}
	catch (ClassNotFoundException e)
	{
	LOG.ignore(e);
	}

	//find the tld files and parse them to get out their
	//listeners
	Set<Resource> tlds = findTldResources();
	List<TldDescriptor> descriptors = parseTlds(tlds);
	processTlds(descriptors);

	if (_tldListeners == null)
	return;

	//call the listeners that are ServletContextListeners, put the
	//rest into the context's list of listeners to call at the appropriate
	//moment
	for (EventListener l:_tldListeners) {
	if (l instanceof ServletContextListener) {
	((ServletContextListener)l).contextInitialized(sce);
	} else {
	_context.addEventListener(l);
	}
	}

	}
	catch (Exception e) {
	LOG.warn(e);
	}
	}




	private Resource extractJarResource (Resource r)
	{
	if (r == null)
	return null;

	try
	{
	String url = r.getURI().toURL().toString();
	int idx = url.lastIndexOf("!/");
	if (idx >= 0)
	url = url.substring(0, idx);
	if (url.startsWith("jar:"))
	url = url.substring(4);
	return Resource.newResource(url);
	}
	catch (IOException e)
	{
	LOG.warn(e);
	return null;
	}
	}

	/**
	* Find all the locations that can harbour tld files that may contain
	* a listener which the web container is supposed to instantiate and
	* call.
	*
	* @return
	* @throws IOException
	*/
	private Set<Resource> findTldResources () throws IOException {

	Set<Resource> tlds = new HashSet<Resource>();

	// Find tld's from web.xml
	// When web.xml was processed, it should have created aliases for all TLDs. So search resources aliases
	// for aliases ending in tld
	if (_context.getResourceAliases()!=null &&
	_context.getBaseResource()!=null &&
	_context.getBaseResource().exists())
	{
	Iterator<String> iter=_context.getResourceAliases().values().iterator();
	while(iter.hasNext())
	{
	String location = iter.next();
	if (location!=null && location.toLowerCase(Locale.ENGLISH).endsWith(".tld"))
	{
	if (!location.startsWith("/"))
	location="/WEB-INF/"+location;
	Resource l=_context.getBaseResource().addPath(location);
	tlds.add(l);
	}
	}
	}

	// Look for any tlds in WEB-INF directly.
	Resource web_inf = _context.getWebInf();
	if (web_inf!=null)
	{
	String[] contents = web_inf.list();
	for (int i=0;contents!=null && i<contents.length;i++)
	{
	if (contents[i]!=null && contents[i].toLowerCase(Locale.ENGLISH).endsWith(".tld"))
	{
	Resource l=web_inf.addPath(contents[i]);
	tlds.add(l);
	}
	}
	}

	//Look for tlds in common location of WEB-INF/tlds
	if (web_inf != null) {
	Resource web_inf_tlds = _context.getWebInf().addPath("/tlds/");
	if (web_inf_tlds.exists() && web_inf_tlds.isDirectory()) {
	String[] contents = web_inf_tlds.list();
	for (int i=0;contents!=null && i<contents.length;i++)
	{
	if (contents[i]!=null && contents[i].toLowerCase(Locale.ENGLISH).endsWith(".tld"))
	{
	Resource l=web_inf_tlds.addPath(contents[i]);
	tlds.add(l);
	}
	}
	}
	}

	// Add in tlds found in META-INF of jars. The jars that will be scanned are controlled by
	// the patterns defined in the context attributes: org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern,
	// and org.eclipse.jetty.server.webapp.WebInfIncludeJarPattern
	@SuppressWarnings("unchecked")
	Collection<Resource> tld_resources=(Collection<Resource>)_context.getAttribute(TLD_RESOURCES);
	if (tld_resources!=null)
	tlds.addAll(tld_resources);

	return tlds;
	}


	/**
	* Parse xml into in-memory tree
	* @param tlds
	* @return
	*/
	private List<TldDescriptor> parseTlds (Set<Resource> tlds) {
	List<TldDescriptor> descriptors = new ArrayList<TldDescriptor>();

	Resource tld = null;
	Iterator<Resource> iter = tlds.iterator();
	while (iter.hasNext())
	{
	try
	{
	tld = iter.next();
	if (LOG.isDebugEnabled()) LOG.debug("TLD="+tld);

	TldDescriptor d = new TldDescriptor(tld);
	d.parse();
	descriptors.add(d);
	}
	catch(Exception e)
	{
	LOG.warn("Unable to parse TLD: " + tld,e);
	}
	}
	return descriptors;
	}


	/**
	* Create listeners from the parsed tld trees
	* @param descriptors
	* @throws Exception
	*/
	private void processTlds (List<TldDescriptor> descriptors) throws Exception {

	TldProcessor processor = new TldProcessor();
	for (TldDescriptor d:descriptors)
	processor.process(_context, d);

	_tldListeners = new ArrayList<EventListener>(processor.getListeners());
	}
	}




	/**
	* TldDescriptor
	*
	*
	*/
	public static class TldDescriptor extends Descriptor
	{
	protected static XmlParser __parserSingleton;

	public TldDescriptor(Resource xml)
	{
	super(xml);
	}

	@Override
	public void ensureParser() throws ClassNotFoundException
	{
	if (__parserSingleton == null)
	__parserSingleton = newParser();
	_parser = __parserSingleton;
	}

	@Override
	public XmlParser newParser() throws ClassNotFoundException
	{
	// Create a TLD parser
	XmlParser parser = new XmlParser(false);

	URL taglib11=null;
	URL taglib12=null;
	URL taglib20=null;
	URL taglib21=null;

	try
	{
	Class<?> jsp_page = Loader.loadClass(WebXmlConfiguration.class,"javax.servlet.jsp.JspPage");
	taglib11=jsp_page.getResource("javax/servlet/jsp/resources/web-jsptaglibrary_1_1.dtd");
	taglib12=jsp_page.getResource("javax/servlet/jsp/resources/web-jsptaglibrary_1_2.dtd");
	taglib20=jsp_page.getResource("javax/servlet/jsp/resources/web-jsptaglibrary_2_0.xsd");
	taglib21=jsp_page.getResource("javax/servlet/jsp/resources/web-jsptaglibrary_2_1.xsd");
	}
	catch(Exception e)
	{
	LOG.ignore(e);
	}
	finally
	{
	if(taglib11==null)
	taglib11=Loader.getResource(Servlet.class,"javax/servlet/jsp/resources/web-jsptaglibrary_1_1.dtd",true);
	if(taglib12==null)
	taglib12=Loader.getResource(Servlet.class,"javax/servlet/jsp/resources/web-jsptaglibrary_1_2.dtd",true);
	if(taglib20==null)
	taglib20=Loader.getResource(Servlet.class,"javax/servlet/jsp/resources/web-jsptaglibrary_2_0.xsd",true);
	if(taglib21==null)
	taglib21=Loader.getResource(Servlet.class,"javax/servlet/jsp/resources/web-jsptaglibrary_2_1.xsd",true);
	}


	if(taglib11!=null)
	{
	redirect(parser, "web-jsptaglib_1_1.dtd",taglib11);
	redirect(parser, "web-jsptaglibrary_1_1.dtd",taglib11);
	}
	if(taglib12!=null)
	{
	redirect(parser, "web-jsptaglib_1_2.dtd",taglib12);
	redirect(parser, "web-jsptaglibrary_1_2.dtd",taglib12);
	}
	if(taglib20!=null)
	{
	redirect(parser, "web-jsptaglib_2_0.xsd",taglib20);
	redirect(parser, "web-jsptaglibrary_2_0.xsd",taglib20);
	}
	if(taglib21!=null)
	{
	redirect(parser, "web-jsptaglib_2_1.xsd",taglib21);
	redirect(parser, "web-jsptaglibrary_2_1.xsd",taglib21);
	}

	parser.setXpath("/taglib/listener/listener-class");
	return parser;
	}

	public void parse ()
	throws Exception
	{
	ensureParser();
	try
	{
	//xerces on apple appears to sometimes close the zip file instead
	//of the inputstream, so try opening the input stream, but if
	//that doesn't work, fallback to opening a new url
	_root = _parser.parse(_xml.getInputStream());
	}
	catch (Exception e)
	{
	_root = _parser.parse(_xml.getURL().toString());
	}

	if (_root==null)
	{
	LOG.warn("No TLD root in {}",_xml);
	}
	}
	}


	/**
	* TldProcessor
	*
	* Process TldDescriptors representing tag libs to find listeners.
	*/
	public class TldProcessor extends IterativeDescriptorProcessor
	{
	public static final String TAGLIB_PROCESSOR = "org.eclipse.jetty.tagLibProcessor";
	XmlParser _parser;
	List<XmlParser.Node> _roots = new ArrayList<XmlParser.Node>();
	List<EventListener> _listeners;


	public TldProcessor ()
	throws Exception
	{
	_listeners = new ArrayList<EventListener>();
	registerVisitor("listener", this.getClass().getDeclaredMethod("visitListener", __signature));
	}


	public void visitListener (WebAppContext context, Descriptor descriptor, XmlParser.Node node)
	{
	String className=node.getString("listener-class",false,true);
	if (LOG.isDebugEnabled())
	LOG.debug("listener="+className);

	try
	{
	Class<?> listenerClass = context.loadClass(className);
	EventListener l = (EventListener)listenerClass.newInstance();
	_listeners.add(l);
	}
	catch(Exception e)
	{
	LOG.warn("Could not instantiate listener "+className+": "+e);
	LOG.debug(e);
	}
	catch(Error e)
	{
	LOG.warn("Could not instantiate listener "+className+": "+e);
	LOG.debug(e);
	}

	}

	@Override
	public void end(WebAppContext context, Descriptor descriptor)
	{
	}

	@Override
	public void start(WebAppContext context, Descriptor descriptor)
	{
	}

	public List<EventListener> getListeners() {
	return _listeners;
	}
	}


	@Override
	public void preConfigure(WebAppContext context) throws Exception
	{
	try
	{
	Class<?> jsp_page = Loader.loadClass(WebXmlConfiguration.class,"javax.servlet.jsp.JspPage");
	}
	catch (Exception e)
	{
	//no jsp available, don't parse TLDs
	return;
	}

	TagLibListener tagLibListener = new TagLibListener(context);
	context.addEventListener(tagLibListener);
	}


	@Override
	public void configure (WebAppContext context) throws Exception
	{
	}

	@Override
	public void postConfigure(WebAppContext context) throws Exception
	{
	}


	@Override
	public void cloneConfigure(WebAppContext template, WebAppContext context) throws Exception
	{
	}


	@Override
	public void deconfigure(WebAppContext context) throws Exception
	{
	}
	}