/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.myfaces.component.html.util;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.io.UnsupportedEncodingException;
  import java.net.URLEncoder;
  import java.util.Map;
  import java.util.Set;
  import java.util.TreeSet;
  
  import javax.faces.FacesException;
  import javax.faces.context.FacesContext;
  import javax.faces.context.ResponseWriter;
  import javax.servlet.ServletContext;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.apache.commons.lang.builder.EqualsBuilder;
  import org.apache.commons.lang.builder.HashCodeBuilder;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.myfaces.component.html.util.StreamingThreadManager.HeaderInfoEntry;
  import org.apache.myfaces.renderkit.html.util.AddResource;
  import org.apache.myfaces.renderkit.html.util.AddResource2;
  import org.apache.myfaces.renderkit.html.util.MyFacesResourceHandler;
  import org.apache.myfaces.renderkit.html.util.ResourceHandler;
  import org.apache.myfaces.renderkit.html.util.ResourceLoader;
  import org.apache.myfaces.renderkit.html.util.ResourcePosition;
  import org.apache.myfaces.shared_tomahawk.config.MyfacesConfig;
  import org.apache.myfaces.shared_tomahawk.renderkit.html.HTML;
  import org.apache.myfaces.shared_tomahawk.util.ClassUtils;
  import org.apache.myfaces.tomahawk.util.ExternalContextUtils;
  import org.apache.myfaces.webapp.filter.PortletUtils;
  
  /**
   * This is a utility class to render link to resources used by custom components.
   * <p>
   * This enables a JSF component that is within a page to register scripts and
   * css stylesheets that it needs, and have them added to the page output.
   * When multiple components in a page registers a need for the same script or
   * stylesheet multiple times, only one reference is output in the page.
   * <p>
   * The default DefaultAddResources implementation achieves this by buffering the
   * complete page in memory until after rendering is complete, then post-processing
   * the page; this implementation does not require buffering the output but does
   * have some limitations.
   * <p>
   * To enable the use of this implementation, the web.xml of the application must
   * set property ????
   * <p>
   * For references to external resources (javascript files or css files), the url
   * rendered into the page has the special format:
   * <pre>
   * {contextPath}/faces/myFacesExtensionResource/
   *    {resourceLoaderName}/{cacheKey}/{resourceURI}
   * </pre>
   * Where:
   * <ul>
   * <li> {contextPath} is the context path of the current webapp
   * <li> {resourceLoaderName} is the fully-qualified name of a class which
   *  implements the ResourceLoader interface. When a browser app sends a request
   *  for the specified resource, an instance of the specified ResourceLoader class
   *  will be created and passed the resourceURI part of the URL for resolving to the
   *  actual resource to be served back. The standard MyFaces ResourceLoader
   *  implementation only serves resources for files stored beneath path
   *  org/apache/myfaces/custom in the classpath but non-myfaces code can provide their
   *  own ResourceLoader implementations.
   * <li> {cacheKey} is a value provided by the ResourceLoader. For the standard ResourceLoader
   * that returns resources from the tomahawk jarfile, this timestamp is the datetime at which the
   * tomahawk library was built. This means that browsers will cache these resources for efficiency but
   * hen a new version of the tomahawk jarfile is deployed then the url changes, so that new versions
   * of the resources are picked up. Where a "build timestamp" is not available, the startup time of
   * the webserver is a reasonable alternative; that means that webbrowsers will cache resources until
   * the webserver is restarted.
   * </ul>
   * <p>
   * As specified in the base AddResource interface, most methods come in two flavours: one that takes
   * an explicit ResourceHandler parameter (so can be used by "user" code) and one that implicitly
   * uses a ResourceHandler that serves only Tomahawk resources (ie is intended for use only by
   * Tomahawk components). For the tomahawk-specific methods, the standard MyFacesResourceHandler is
   * used, which in turn uses the standard MyFacesResourceLoader. However for resources that must be
  * cached and served in a separate request (see below) the custom StreamingResourceHandler is used,
  * which uses StreamingResourceLoader.
  * <p>
  * The DefaultAddResource implementation inserts javascript file references into the head section of
  * the generated page. This streaming implementation cannot do that, so it inserts them into the
  * body of the page instead. This is not technically valid; according to the HTML spec references
  * to external javascript files should be in the HEAD only. However all modern browsers do support this.
  * There may be some corner cases where this does result in different behaviour of the page.
  * <p>
  * The DefaultAddResource implementation inserts css file references into the head section of the
  * generated page by post-processing the page output after all components have finished rendering.
  * This streaming implementation cannot do that, and no browser supports references to stylesheets
  * from within the HTML page body. Therefore this class implements a workaround: it expects that
  * every page will always emits a single CSS link to a "virtual page" from its HEAD section and then
  * handles the later request for that virtual page by serving any resources that really should
  * have been embedded in the head of the original page. When the page uses the t:documentHead tag to
  * rite the HEAD tags of the page, this link is emitted automatically. This does unfortunately mean
  * that use of this StreamingAddResource <i>always</i> results in an extra GET request per page. It
  * also means that there needs to be an application-scoped cache that holds per-request cached data,
  * which introduces some issues regarding "cleanup" of the cache entries. See javadoc of method
  * addStyleLoaderHere() for more details.
  *
  * @author Mario Ivankovits (latest modification by $Author: lu4242 $)
  * @version $Revision: 954965 $ $Date: 2010-06-15 11:58:31 -0500 (Tue, 15 Jun 2010) $
  */
 public class StreamingAddResource extends AddResource2
 {
     /**
      * central place where all request store their "to be added" stylesheets
      */
     //private final static Map headerInfos = new HashMap();
 
     /**
      * request counter
      */
     private static long REQUEST_ID_COUNTER = 0;
 
     /**
      * own request
      */
     private Long requestId;
 
     /**
      * own header infos - e.g holds the "to be added" stylesheets and a destroy time
      */
     private HeaderInfoEntry headerInfoEntry;
 
     /**
      * helper to determines if the resource has already been added
      */
     private Set alreadySeenResources = new TreeSet();
 
     private static final String PATH_SEPARATOR = "/";
 
     protected static final Log log = LogFactory.getLog(StreamingAddResource.class);
     protected static final Log logSend = LogFactory.getLog(StreamingAddResource.class.getName() + ".SEND");
 
     private static final String RESOURCE_VIRTUAL_PATH = "/faces/myFacesExtensionResource";
 
     private static final String RESOURCES_CACHE_KEY = AddResource.class.getName() + ".CACHE_KEY";
 
     protected String _contextPath;
     private String resourceVirtualPath;
 /*
     public static class HeaderInfoEntry
     {
         private final long destroyTime = System.currentTimeMillis() + (1000 * 60); // one minute;
         private final List addedInfos = new ArrayList(10);
         private volatile boolean requestDone = false;
 
         protected HeaderInfoEntry()
         {
         }
 
         protected boolean isDestroyable(long now)
         {
             return destroyTime < now;
         }
 
         protected void addInfo(StreamablePositionedInfo positionedInfo)
         {
             synchronized (addedInfos)
             {
                 addedInfos.add(positionedInfo);
                 addedInfos.notifyAll();
             }
         }
 
         protected StreamablePositionedInfo fetchInfo() throws InterruptedException
         {
             synchronized (addedInfos)
             {
                 while (addedInfos.size() < 1 && !requestDone)
                 {
                     addedInfos.wait(100);
                 }
                 if (addedInfos.size() < 1)
                 {
                     // request done
                     return null;
                 }
 
                 return (StreamablePositionedInfo) addedInfos.remove(0);
             }
         }
 
         protected void setRequestDone()
         {
             requestDone = true;
         }
     }
 
     private static class CleanupThread implements Runnable
     {
         // how many entries should be removed per run
         private final static int CHECKS_PER_RUN = 10;
 
         // but never reach this maximum
         private final static int CACHE_LIMIT = 1000;
 
         public void run()
         {
             while (!Thread.interrupted())
             {
                 checkMap();
 
                 try
                 {
                     Thread.sleep(1000 * 30); // check every 30 sek
                 }
                 catch (InterruptedException e)
                 {
                     // ignore
                 }
             }
         }
 
         private void checkMap()
         {
             synchronized (headerInfos)
             {
                 long now = System.currentTimeMillis();
 
                 int checkNo = 0;
                 Iterator iterEntries = headerInfos.entrySet().iterator();
                 while (iterEntries.hasNext() && !Thread.currentThread().isInterrupted())
                 {
                     checkNo++;
                     if (headerInfos.size() < CACHE_LIMIT && checkNo > CHECKS_PER_RUN)
                     {
                         return;
                     }
                     Map.Entry entry = (Map.Entry) iterEntries.next();
                     HeaderInfoEntry headerInfoEntry = (HeaderInfoEntry) entry.getValue();
                     if (headerInfoEntry.isDestroyable(now))
                     {
                         iterEntries.remove();
                     }
                 }
             }
         }
     }
 
     static
     {
         Thread cleanupThread = new Thread(new CleanupThread(), "StreamingAddResource.CleanupThread");
         cleanupThread.setDaemon(true);
         cleanupThread.start();
     }
     */
 
     public StreamingAddResource()
     {
     }
     /*
     public static HeaderInfoEntry getHeaderInfo(Long requestId)
     {
         synchronized (headerInfos)
         {
             return (HeaderInfoEntry) headerInfos.get(requestId);
         }
     }
 
     public static void removeHeaderInfo(Long requestId)
     {
         synchronized (headerInfos)
         {
             headerInfos.remove(requestId);
         }
     }*/
 
     // Methods to add resources
 
     public void setContextPath(String contextPath)
     {
         _contextPath = contextPath;
     }
 
     /**
      * Insert a [script src="url"] entry at the current location in the response.
      * The resource is expected to be in the classpath, at the same location as the
      * specified component + "/resource".
      * <p>
      * Example: when customComponent is class example.Widget, and
      * resourceName is script.js, the resource will be retrieved from
      * "example/Widget/resource/script.js" in the classpath.
      */
     public void addJavaScriptHere(FacesContext context, Class myfacesCustomComponent,
                                   String resourceName) throws IOException
     {
         addJavaScriptHere(context, new MyFacesResourceHandler(myfacesCustomComponent, resourceName));
     }
 
     /**
      * Insert a [script src="url"] entry at the current location in the response.
      *
      * @param uri is the location of the desired resource, relative to the base
      * directory of the webapp (ie its contextPath).
      */
     public void addJavaScriptHere(FacesContext context, String uri) throws IOException
     {
         ResponseWriter writer = context.getResponseWriter();
 
         writer.startElement(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SCRIPT_ELEM, null);
         writer.writeAttribute(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SCRIPT_TYPE_ATTR, org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SCRIPT_TYPE_TEXT_JAVASCRIPT, null);
         String src = context.getExternalContext().encodeResourceURL(getResourceUri(context, uri));
         writer.writeURIAttribute(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SRC_ATTR, src, null);
         writer.endElement(HTML.SCRIPT_ELEM);
     }
 
     public void addJavaScriptHerePlain(FacesContext context, String uri) throws IOException
     {
         ResponseWriter writer = context.getResponseWriter();
 
         writer.startElement(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SCRIPT_ELEM, null);
         writer.writeAttribute(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SCRIPT_TYPE_ATTR, org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SCRIPT_TYPE_TEXT_JAVASCRIPT, null);
         String src = getResourceUri(context, uri);
         writer.writeURIAttribute(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SRC_ATTR, src, null);
         writer.endElement(HTML.SCRIPT_ELEM);
     }
 
     /**
      * Insert a [script src="url"] entry at the current location in the response.
      *
      * @param context
      *
      * @param resourceHandler is an object which specifies exactly how to build the url
      * that is emitted into the script tag. Code which needs to generate URLs in ways
      * that this class does not support by default can implement a custom ResourceHandler.
      *
      * @throws IOException
      */
     public void addJavaScriptHere(FacesContext context, ResourceHandler resourceHandler)
             throws IOException
     {
         validateResourceHandler(resourceHandler);
 
         ResponseWriter writer = context.getResponseWriter();
 
         writer.startElement(HTML.SCRIPT_ELEM, null);
         writer.writeAttribute(HTML.SCRIPT_TYPE_ATTR, HTML.SCRIPT_TYPE_TEXT_JAVASCRIPT, null);
         String src = context.getExternalContext().encodeResourceURL(
                 getResourceUri(context, resourceHandler));
         writer.writeURIAttribute(HTML.SRC_ATTR, src, null);
         writer.endElement(HTML.SCRIPT_ELEM);
     }
 
     public void addResourceHere(FacesContext context, ResourceHandler resourceHandler)
             throws IOException
     {
         validateResourceHandler(resourceHandler);
 
         String path = getResourceUri(context, resourceHandler);
         ResponseWriter writer = context.getResponseWriter();
         writer.write(context.getExternalContext().encodeResourceURL(path));
     }
 
     /**
      * Verify that the resource handler is acceptable. Null is not
      * valid, and the getResourceLoaderClass method must return a
      * Class object whose instances implements the ResourceLoader
      * interface.
      *
      * @param resourceHandler
      */
     protected void validateResourceHandler(ResourceHandler resourceHandler)
     {
         if (resourceHandler == null)
         {
             throw new IllegalArgumentException("ResourceHandler is null");
         }
         validateResourceLoader(resourceHandler.getResourceLoaderClass());
     }
 
     /**
      * Given a Class object, verify that the instances of that class
      * implement the ResourceLoader interface.
      *
      * @param resourceloader
      */
     protected void validateResourceLoader(Class resourceloader)
     {
         if (!ResourceLoader.class.isAssignableFrom(resourceloader))
         {
             throw new FacesException("Class " + resourceloader.getName() + " must implement "
                     + ResourceLoader.class.getName());
         }
     }
 
     /**
      * Adds the given Javascript resource to the document header at the specified
      * document positioy by supplying a resourcehandler instance.
      * <p>
      * Use this method to have full control about building the reference url
      * to identify the resource and to customize how the resource is
      * written to the response. In most cases, however, one of the convenience
      * methods on this class can be used without requiring a custom ResourceHandler
      * to be provided.
      * <p>
      * If the script has already been referenced, it's added only once.
      * <p>
      * Note that this method <i>queues</i> the javascript for insertion, and that
      * the script is inserted into the buffered response by the ExtensionsFilter
      * after the page is complete.
      */
     public void addJavaScriptAtPosition(FacesContext context, ResourcePosition position,
                                         ResourceHandler resourceHandler)
     {
         addJavaScriptAtPosition(context, position, resourceHandler, false);
     }
 
     /**
      * Insert a [script src="url"] entry into the document header at the
      * specified document position. If the script has already been
      * referenced, it's added only once.
      * <p>
      * The resource is expected to be in the classpath, at the same location as the
      * specified component + "/resource".
      * <p>
      * Example: when customComponent is class example.Widget, and
      * resourceName is script.js, the resource will be retrieved from
      * "example/Widget/resource/script.js" in the classpath.
      */
     public void addJavaScriptAtPosition(FacesContext context, ResourcePosition position,
                                         Class myfacesCustomComponent, String resourceName)
     {
         addJavaScriptAtPosition(context, position, new MyFacesResourceHandler(
                 myfacesCustomComponent, resourceName));
     }
 
     public void addJavaScriptAtPositionPlain(FacesContext context, ResourcePosition position, Class myfacesCustomComponent, String resourceName)
     {
         addJavaScriptAtPosition(context, position,
                 new MyFacesResourceHandler(myfacesCustomComponent, resourceName),
                 false, false);
     }
 
     /**
      * Insert a [script src="url"] entry into the document header at the
      * specified document position. If the script has already been
      * referenced, it's added only once.
      *
      * @param defer specifies whether the html attribute "defer" is set on the
      * generated script tag. If this is true then the browser will continue
      * processing the html page without waiting for the specified script to
      * load and be run.
      */
     public void addJavaScriptAtPosition(FacesContext context, ResourcePosition position,
                                         Class myfacesCustomComponent, String resourceName, boolean defer)
     {
         addJavaScriptAtPosition(context, position, new MyFacesResourceHandler(
                 myfacesCustomComponent, resourceName), defer);
     }
 
     /**
      * Insert a [script src="url"] entry into the document header at the
      * specified document position. If the script has already been
      * referenced, it's added only once.
      *
      * @param uri is the location of the desired resource, relative to the base
      * directory of the webapp (ie its contextPath).
      */
     public void addJavaScriptAtPosition(FacesContext context, ResourcePosition position, String uri)
     {
         addJavaScriptAtPosition(context, position, uri, false);
     }
 
     /**
      * Adds the given Javascript resource at the specified document position.
      * If the script has already been referenced, it's added only once.
      */
     public void addJavaScriptAtPosition(FacesContext context, ResourcePosition position, String uri,
                                         boolean defer)
     {
         WritablePositionedInfo info = (WritablePositionedInfo) getScriptInstance(context, uri, defer);
         if (checkAlreadyAdded(info))
         {
             return;
         }
         HttpServletResponse response = (HttpServletResponse) context.getExternalContext().getResponse();
         try
         {
             info.writePositionedInfo(response, context.getResponseWriter());
         }
         catch (IOException e)
         {
             throw new RuntimeException(e);
         }
     }
 
     public void addJavaScriptToBodyTag(FacesContext context, String javascriptEventName,
                                        String addedJavaScript)
     {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Adds the given Javascript resource at the specified document position.
      * If the script has already been referenced, it's added only once.
      */
     public void addJavaScriptAtPosition(FacesContext context, ResourcePosition position, ResourceHandler resourceHandler, boolean defer)
     {
         addJavaScriptAtPosition(context, position, resourceHandler, defer, false);
     }
 
     private void addJavaScriptAtPosition(FacesContext context, ResourcePosition position,
                                          ResourceHandler resourceHandler, boolean defer, boolean encodeURL)
     {
         validateResourceHandler(resourceHandler);
         WritablePositionedInfo info = (WritablePositionedInfo) getScriptInstance(context, resourceHandler, defer, encodeURL);
         if (checkAlreadyAdded(info))
         {
             return;
         }
         HttpServletResponse response = (HttpServletResponse) context.getExternalContext().getResponse();
         try
         {
             info.writePositionedInfo(response, context.getResponseWriter());
         }
         catch (IOException e)
         {
             throw new RuntimeException(e);
         }
     }
 
     private boolean checkAlreadyAdded(PositionedInfo info)
     {
         Long key = new Long(info.hashCode());
         if (alreadySeenResources.contains(key))
         {
             return true;
         }
 
         alreadySeenResources.add(key);
         return false;
     }
 
     /**
      * Adds the given Style Sheet at the specified document position.
      * If the style sheet has already been referenced, it's added only once.
      */
     public void addStyleSheet(FacesContext context, ResourcePosition position,
                               Class myfacesCustomComponent, String resourceName)
     {
         addStyleSheet(context, position, new MyFacesResourceHandler(myfacesCustomComponent,
                 resourceName));
     }
 
     /**
      * Adds the given Style Sheet at the specified document position.
      * If the style sheet has already been referenced, it's added only once.
      */
     public void addStyleSheet(FacesContext context, ResourcePosition position, String uri)
     {
         uri = getAbsoluteUri(context, uri);
 
         addStyleSheet(context, getStyleInstance(context, uri));
     }
 
     protected String getAbsoluteUri(FacesContext context, String uri)
     {
         if (uri.startsWith("/"))
         {
             return uri;
         }
 
         StringBuffer sb = new StringBuffer(80);
         if (context.getExternalContext().getRequestPathInfo() != null)
         {
             sb.append(context.getExternalContext().getRequestPathInfo());
         }
         sb.append("/");
         sb.append(uri);
 
         return sb.toString();
     }
 
     private void addStyleSheet(FacesContext context, StreamablePositionedInfo styleInstance)
     {
         if (checkAlreadyAdded(styleInstance))
         {
             return;
         }
         StreamingThreadManager manager = (StreamingThreadManager) context.getExternalContext().getApplicationMap().get(StreamingThreadManager.KEY);
         getHeaderInfoEntry().addInfo(styleInstance);
     }
 
     /**
      * Adds the given Style Sheet at the specified document position.
      * If the style sheet has already been referenced, it's added only once.
      */
     public void addStyleSheet(FacesContext context, ResourcePosition position,
                               ResourceHandler resourceHandler)
     {
         validateResourceHandler(resourceHandler);
         addStyleSheet(context, getStyleInstance(context, resourceHandler));
     }
 
     /**
      * Adds the given Inline Style at the specified document position.
      */
     public void addInlineStyleAtPosition(FacesContext context, ResourcePosition position, String inlineStyle)
     {
         addStyleSheet(context, getInlineStyleInstance(inlineStyle));
     }
 
     /**
      * Adds the given Inline Script at the specified document position.
      */
     public void addInlineScriptAtPosition(FacesContext context, ResourcePosition position,
                                           String inlineScript)
     {
         WritablePositionedInfo info = (WritablePositionedInfo) getInlineScriptInstance(inlineScript);
         if (checkAlreadyAdded(info))
         {
             return;
         }
         HttpServletResponse response = (HttpServletResponse) context.getExternalContext().getResponse();
         try
         {
             info.writePositionedInfo(response, context.getResponseWriter());
         }
         catch (IOException e)
         {
             throw new RuntimeException(e);
         }
     }
 
     public String getResourceUri(FacesContext context, Class myfacesCustomComponent,
                                  String resource, boolean withContextPath)
     {
         return getResourceUri(context,
                 new MyFacesResourceHandler(myfacesCustomComponent, resource), withContextPath);
     }
 
     public String getResourceUri(FacesContext context, Class myfacesCustomComponent, String resource)
     {
         return getResourceUri(context, new MyFacesResourceHandler(myfacesCustomComponent, resource));
     }
 
     /**
      * Get the Path used to retrieve an resource.
      */
     public String getResourceUri(FacesContext context, ResourceHandler resourceHandler)
     {
         String uri = resourceHandler.getResourceUri(context);
         if (uri == null)
         {
             return getResourceUri(context, resourceHandler.getResourceLoaderClass(), true);
         }
         return getResourceUri(context, resourceHandler.getResourceLoaderClass(), true) + uri;
     }
 
     /**
      * Get the Path used to retrieve an resource.
      */
     public String getResourceUri(FacesContext context, ResourceHandler resourceHandler,
                                  boolean withContextPath)
     {
         String uri = resourceHandler.getResourceUri(context);
         if (uri == null)
         {
             return getResourceUri(context, resourceHandler.getResourceLoaderClass(),
                     withContextPath);
         }
         return getResourceUri(context, resourceHandler.getResourceLoaderClass(), withContextPath)
                 + uri;
     }
 
     /**
      * Get the Path used to retrieve an resource.
      */
     public String getResourceUri(FacesContext context, String uri)
     {
         return getResourceUri(context, uri, true);
     }
 
     /**
      * Get the Path used to retrieve an resource.
      */
     public String getResourceUri(FacesContext context, String uri, boolean withContextPath)
     {
         if (withContextPath)
         {
             return context.getApplication().getViewHandler().getResourceURL(context, uri);
         }
         return uri;
     }
 
     /**
      * Get the Path used to retrieve an resource.
      */
     protected String getResourceUri(FacesContext context, Class resourceLoader,
                                     boolean withContextPath)
     {
         StringBuffer sb = new StringBuffer(200);
         sb.append(MyfacesConfig.getCurrentInstance(context.getExternalContext()).getResourceVirtualPath());
         sb.append(PATH_SEPARATOR);
         sb.append(resourceLoader.getName());
         sb.append(PATH_SEPARATOR);
         sb.append(getCacheKey(context));
         sb.append(PATH_SEPARATOR);
         return getResourceUri(context, sb.toString(), withContextPath);
     }
 
     /**
      * Return a value used in the {cacheKey} part of a generated URL for a
      * resource reference.
      * <p>
      * Caching in browsers normally works by having files served to them
      * include last-modified and expiry-time http headers. Until the expiry
      * time is reached, a browser will silently use its cached version. After
      * the expiry time, it will send a "get if modified since {time}" message,
      * where {time} is the last-modified header from the version it has cached.
      * <p>
      * Unfortunately this scheme only works well for resources represented as
      * plain files on disk, where the webserver can easily and efficiently see
      * the last-modified time of the resource file. When that query has to be
      * processed by a servlet that doesn't scale well, even when it is possible
      * to determine the resource's last-modified date from servlet code.
      * <p>
      * Fortunately, for the AddResource class a static resource is only ever
      * accessed because a URL was embedded by this class in a dynamic page.
      * This makes it possible to implement caching by instead marking every
      * resource served with a very long expiry time, but forcing the URL that
      * points to the resource to change whenever the old cached version becomes
      * invalid; the browser effectively thinks it is fetching a different
      * resource that it hasn't seen before. This is implemented by embedding
      * a "cache key" in the generated URL.
      * <p>
      * Rather than using the actual modification date of a resource as the
      * cache key, we simply use the webapp deployment time. This means that all
      * data cached by browsers will become invalid after a webapp deploy (all
      * the urls to the resources change). It also means that changes that occur
      * to a resource <i>without</i> a webapp redeploy will not be seen by browsers.
      */
     protected long getCacheKey(FacesContext context)
     {
         // cache key is hold in application scope so it is recreated on redeploying the webapp.
         Map applicationMap = context.getExternalContext().getApplicationMap();
         Long cacheKey = (Long) applicationMap.get(RESOURCES_CACHE_KEY);
         if (cacheKey == null)
         {
             cacheKey = new Long(System.currentTimeMillis() / 100000);
             applicationMap.put(RESOURCES_CACHE_KEY, cacheKey);
         }
         return cacheKey.longValue();
     }
 
     public boolean isResourceUri(ServletContext servletContext, HttpServletRequest request)
     {
         String path;
         if (_contextPath != null)
         {
             path = _contextPath + getResourceVirtualPath(servletContext);
         }
         else
         {
             path = getResourceVirtualPath(servletContext);
         }
 
         //fix for TOMAHAWK-660; to be sure this fix is backwards compatible, the
         //encoded context-path is only used as a first option to check for the prefix
         //if we're sure this works for all cases, we can directly return the first value
         //and not double-check.
         try
         {
             if(request.getRequestURI().startsWith(URLEncoder.encode(path,"UTF-8")))
                 return true;
         }
         catch (UnsupportedEncodingException e)
         {
             log.error("Unsupported encoding UTF-8 used",e);
 
         }
 
         return request.getRequestURI().startsWith(path);
     }
 
     private Class getClass(String className) throws ClassNotFoundException
     {
         Class clazz = ClassUtils.classForName(className);
         validateResourceLoader(clazz);
         return clazz;
     }
 
     public void serveResource(ServletContext context, HttpServletRequest request,
                               HttpServletResponse response) throws IOException
     {
         String pathInfo = request.getPathInfo();
         String uri = request.getContextPath() + request.getServletPath()
                 + (pathInfo == null ? "" : pathInfo);
         String classNameStartsAfter = getResourceVirtualPath(context) + '/';
 
         int posStartClassName = uri.indexOf(classNameStartsAfter) + classNameStartsAfter.length();
         int posEndClassName = uri.indexOf(PATH_SEPARATOR, posStartClassName);
         String className = uri.substring(posStartClassName, posEndClassName);
         int posEndCacheKey = uri.indexOf(PATH_SEPARATOR, posEndClassName + 1);
         String resourceUri = null;
         if (posEndCacheKey + 1 < uri.length())
         {
             resourceUri = uri.substring(posEndCacheKey + 1);
         }
 
         try
         {
             Class resourceLoader = getClass(className);
             validateResourceLoader(resourceLoader);
             ((ResourceLoader) resourceLoader.newInstance()).serveResource(context, request,
                     response, resourceUri);
             // response.flushBuffer();
             // Do not call response.flushBuffer buffer here. There is no point, as if there
             // ever were header data to write, this would fail as we have already written
             // the response body. The only point would be to flush the output stream, but
             // that will happen anyway when the servlet container closes the socket.
             //
             // In addition, flushing could fail here; it appears that Microsoft IE
             // hasthe habit of hard-closing its socket as soon as it has received a complete
             // gif file, rather than letting the server close it. The container will hopefully
             // silently ignore exceptions on close.            
         }
         catch (ClassNotFoundException e)
         {
             log.error("Could not find class for name: " + className, e);
             sendError(response, HttpServletResponse.SC_NOT_FOUND,
                     "Could not find resourceloader class for name: " + className);
         }
         catch (InstantiationException e)
         {
             log.error("Could not instantiate class for name: " + className, e);
             sendError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
                     "Could not instantiate resourceloader class for name: " + className);
         }
         catch (IllegalAccessException e)
         {
             log.error("Could not access class for name: " + className, e);
             sendError(response, HttpServletResponse.SC_FORBIDDEN,
                     "Could not access resourceloader class for name: " + className);
         }
         catch (IOException e)
         {
             logSend.error("Error while serving resource: " +resourceUri+", message : "+ e.getMessage(), e);
             sendError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e.getMessage());
         }
         catch (Throwable e)
         {
             log.error("Unknown error while serving resource: " +resourceUri+", message : "+ e.getMessage(), e);
             sendError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e.getMessage());
         }
     }
 
     protected void sendError(HttpServletResponse response, int errorCode, String errorText)
         throws IOException
     {
         try
         {
             response.sendError(errorCode, errorText);
         }
         catch (IllegalStateException e)
         {
             logSend.error("Could not send error, maybe some data has already been sent.", e);
         }
     }
 
     public boolean hasHeaderBeginInfos(HttpServletRequest request)
     {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Parses the response to mark the positions where code will be inserted
      */
     public void parseResponse(HttpServletRequest request, String bufferedResponse,
                               HttpServletResponse response)
     {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Writes the javascript code necessary for myfaces in every page, just befode the closing &lt;/body&gt; tag
      */
     public void writeMyFacesJavascriptBeforeBodyEnd(HttpServletRequest request,
                                                     HttpServletResponse response) throws IOException
     {
         throw new UnsupportedOperationException();       
     }
 
     /**
      * Add the resources to the &lt;head&gt; of the page.
      * If the head tag is missing, but the &lt;body&gt; tag is present, the head tag is added.
      * If both are missing, no resource is added.
      *
      * The ordering is such that the user header CSS & JS override the MyFaces' ones.
      */
     public void writeWithFullHeader(HttpServletRequest request,
                                     HttpServletResponse response) throws IOException
     {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Writes the response
      */
     public void writeResponse(HttpServletRequest request,
                               HttpServletResponse response) throws IOException
     {
         throw new UnsupportedOperationException();
     }
 
     private StylePositionedInfo getStyleInstance(FacesContext context, ResourceHandler resourceHandler)
     {
         return new StylePositionedInfo(getResourceUri(context, resourceHandler));
     }
 
     private PositionedInfo getScriptInstance(FacesContext context, ResourceHandler resourceHandler,
                                              boolean defer, boolean encodeUrl)
     {
         return new ScriptPositionedInfo(getResourceUri(context, resourceHandler), defer, encodeUrl);
     }
 
     private StylePositionedInfo getStyleInstance(FacesContext context, String uri)
     {
         return new StylePositionedInfo(getResourceUri(context, uri));
     }
 
     protected PositionedInfo getScriptInstance(FacesContext context, String uri, boolean defer)
     {
         return new ScriptPositionedInfo(getResourceUri(context, uri), defer);
     }
 
     private PositionedInfo getInlineScriptInstance(String inlineScript)
     {
         return new InlineScriptPositionedInfo(inlineScript);
     }
 
     private InlineStylePositionedInfo getInlineStyleInstance(String inlineStyle)
     {
         return new InlineStylePositionedInfo(inlineStyle);
     }
 
     protected interface PositionedInfo
     {
     }
 
     protected interface WritablePositionedInfo extends PositionedInfo
     {
         public abstract void writePositionedInfo(HttpServletResponse response, ResponseWriter writer)
                 throws IOException;
     }
 
     protected interface StreamablePositionedInfo extends PositionedInfo
     {
         public abstract void writePositionedInfo(HttpServletResponse response, PrintWriter writer)
                 throws IOException;
     }
 
     private abstract class AbstractResourceUri
     {
         protected final String _resourceUri;
 
         protected AbstractResourceUri(String resourceUri)
         {
             _resourceUri = resourceUri;
         }
 
         public int hashCode()
         {
             return _resourceUri.hashCode();
         }
 
         public boolean equals(Object obj)
         {
             if (obj == null)
             {
                 return false;
             }
             if (obj == this)
             {
                 return true;
             }
             if (obj instanceof AbstractResourceUri)
             {
                 AbstractResourceUri other = (AbstractResourceUri) obj;
                 return _resourceUri.equals(other._resourceUri);
             }
             return false;
         }
 
         protected String getResourceUri()
         {
             return _resourceUri;
         }
     }
 
     private class StylePositionedInfo extends AbstractResourceUri implements WritablePositionedInfo, StreamablePositionedInfo
     {
         protected StylePositionedInfo(String resourceUri)
         {
             super(resourceUri);
         }
 
         public void writePositionedInfo(HttpServletResponse response, ResponseWriter writer)
                 throws IOException
         {
             writer.startElement(HTML.LINK_ELEM, null);
             writer.writeAttribute(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.REL_ATTR, org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.STYLESHEET_VALUE, null);
             writer.writeAttribute(HTML.HREF_ATTR, response.encodeURL(this.getResourceUri()), null);
             writer.writeAttribute(HTML.TYPE_ATTR, HTML.STYLE_TYPE_TEXT_CSS, null);
             writer.endElement(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.LINK_ELEM);
         }
 
         public void writePositionedInfo(HttpServletResponse response, PrintWriter writer) throws IOException
         {
             writer.println();
             writer.write("@import url(\"");
             writer.write(response.encodeURL(this.getResourceUri()));
             writer.write("\");");
             writer.println();
         }
     }
 
     private class ScriptPositionedInfo extends AbstractResourceUri implements
             WritablePositionedInfo
     {
         protected final boolean _defer;
         protected final boolean _encodeUrl;
 
         public ScriptPositionedInfo(String resourceUri, boolean defer)
         {
             this(resourceUri, defer, true);
         }
 
         public ScriptPositionedInfo(String resourceUri, boolean defer, boolean encodeUrl)
         {
             super(resourceUri);
             _defer = defer;
             _encodeUrl = encodeUrl;
         }
 
         public int hashCode()
         {
             return new HashCodeBuilder()
                 .append(this.getResourceUri())
                 .append(_defer)
                 .append(_encodeUrl)
                 .toHashCode();
         }
 
         public boolean equals(Object obj)
         {
             if (super.equals(obj))
             {
                 if (obj instanceof ScriptPositionedInfo)
                 {
                     ScriptPositionedInfo other = (ScriptPositionedInfo) obj;
                     return new EqualsBuilder()
                         .append(_defer, other._defer)
                         .append(_encodeUrl, other._encodeUrl)
                         .isEquals();
                 }
             }
             return false;
         }
 
         public void writePositionedInfo(HttpServletResponse response, ResponseWriter writer)
                 throws IOException
         {
             writer.startElement(HTML.SCRIPT_ELEM, null);
             writer.writeAttribute(HTML.SCRIPT_TYPE_ATTR, HTML.SCRIPT_TYPE_TEXT_JAVASCRIPT, null);
             if (_encodeUrl)
             {
                 writer.writeAttribute(HTML.SRC_ATTR, response.encodeURL(this.getResourceUri()), null);
             }
             else
             {
                 writer.writeAttribute(HTML.SRC_ATTR, this.getResourceUri(), null);
             }
 
             if (_defer)
             {
                 writer.writeAttribute(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SCRIPT_ELEM_DEFER_ATTR, "true", null);
             }
             writer.endElement(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SCRIPT_ELEM);
         }
     }
 
     private abstract class InlinePositionedInfo implements WritablePositionedInfo
     {
         private final String _inlineValue;
 
         protected InlinePositionedInfo(String inlineValue)
         {
             _inlineValue = inlineValue;
         }
 
         public String getInlineValue()
         {
             return _inlineValue;
         }
 
         public int hashCode()
         {
             return new HashCodeBuilder().append(_inlineValue).toHashCode();
         }
 
         public boolean equals(Object obj)
         {
             if (obj == null)
             {
                 return false;
             }
             if (obj == this)
             {
                 return true;
             }
             if (obj instanceof InlinePositionedInfo)
             {
                 InlinePositionedInfo other = (InlinePositionedInfo) obj;
                 return new EqualsBuilder().append(_inlineValue, other._inlineValue).isEquals();
             }
             return false;
         }
     }
 
     private class InlineScriptPositionedInfo extends InlinePositionedInfo
     {
         protected InlineScriptPositionedInfo(String inlineScript)
         {
             super(inlineScript);
         }
 
         public void writePositionedInfo(HttpServletResponse response, ResponseWriter writer)
                 throws IOException
         {
             writer.startElement(HTML.SCRIPT_ELEM, null);
             writer.writeAttribute(HTML.SCRIPT_TYPE_ATTR, org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.SCRIPT_TYPE_TEXT_JAVASCRIPT, null);
             writer.writeText(getInlineValue(), null);
             writer.endElement(HTML.SCRIPT_ELEM);
         }
     }
 
     private class InlineStylePositionedInfo extends InlinePositionedInfo implements StreamablePositionedInfo
     {
         protected InlineStylePositionedInfo(String inlineStyle)
         {
             super(inlineStyle);
         }
 
         public void writePositionedInfo(HttpServletResponse response, ResponseWriter writer)
                 throws IOException
         {
             writer.startElement(HTML.STYLE_ELEM, null);
             writer.writeAttribute(HTML.REL_ATTR, HTML.STYLESHEET_VALUE, null);
             writer.writeAttribute(HTML.TYPE_ATTR, HTML.STYLE_TYPE_TEXT_CSS, null);
             writer.writeText(getInlineValue(), null);
             writer.endElement(HTML.STYLE_ELEM);
         }
 
         public void writePositionedInfo(HttpServletResponse response, PrintWriter writer) throws IOException
         {
             writer.println();
             writer.write(getInlineValue());
             writer.println();
         }
     }
 
     public boolean requiresBuffer()
     {
         return false;
     }
 
     protected StreamingThreadManager.HeaderInfoEntry getHeaderInfoEntry()
     {
         if (headerInfoEntry == null)
         {
             throw new IllegalStateException("responseStarted() needs to be called first");
         }
 
         return headerInfoEntry;
     }
 
     public void responseStarted()
     {
         /*
         synchronized(StreamingAddResource.class)
         {
             REQUEST_ID_COUNTER++;
             requestId = new Long(REQUEST_ID_COUNTER);
         }
         headerInfoEntry = new HeaderInfoEntry();
         synchronized (headerInfos)
         {
             headerInfos.put(requestId, headerInfoEntry);
         }*/
     }
 
     public void responseFinished()
     {
         getHeaderInfoEntry().setRequestDone();
     }
     
     public void responseStarted(Object context, Object request)
     {
         if(ExternalContextUtils.getRequestType(context, request).isPortlet())
         {
             StreamingThreadManager manager = (StreamingThreadManager) PortletUtils.getAttribute(context, StreamingThreadManager.KEY);
             requestId = manager.putNewHeaderInfoEntry();
             headerInfoEntry = manager.getHeaderInfo(requestId);
         }
         else
         {
             StreamingThreadManager manager = (StreamingThreadManager) ((ServletContext)context).getAttribute(StreamingThreadManager.KEY);
             requestId = manager.putNewHeaderInfoEntry();
             headerInfoEntry = manager.getHeaderInfo(requestId);
         }
     }
 
     public boolean hasHeaderBeginInfos()
     {
         return false;
     }
 
     /**
      * Hack to allow pages to register CSS stylesheet files or inline CSS commands.
      * <p>
      * As described in the class javadocs, the "streaming" approach for resources has problems
      * when it comes to stylesheet links or inline stylesheet commands. These MUST go in the HEAD
      * section of a page, but by the time a component is being rendered the HEAD section is long
      * gone. The DefaultAddResource class can solve this because it buffers the page, but here
      * a different approach is needed.
      * <p>
      * This method should be called during rendering of the HEAD section of a page. For example,
      * the t:documentHead tag (DocumentHeadRenderer) calls this automatically. A link tag of type
      * CSS is written to the response, pointing at a virtual page "header.css" which does not actually exist.
      * <p>
      * During rendering of the page body, component renderers may register inline CSS or CSS files. This
      * info is just cached in the user session. After the page has been sent to the remote browser, the
      * browser will then make a request to the virtual "header.css" page which this class intercepts and
      * then serves up the resources needed by the page.
      * <p>
      * Note that the link to the virtual page must <i>always</i> be rendered, as at this time we do
      * not know whether the body of the page will contain components that need css resources or not.
      * If no component did need CSS resources, then a zero-sized response is returned. And the value
      * can change on each request, depending on which components are rendered or not, so a "requestId"
      * is embedded into the url, making the url change for every request. This requestId is also used
      * to find the relevant cached resources that need to be served (if any).
      * <p>
      * The url is generated using the StreamingResourceHandler (ie StreamingResourceLoader is the class
      * embedded in the url). This means that when the browser fetches this resource, the 
      * StreamingResourceLoader is invoked. It in turn extracts the requestId from the parameter and
      * serves any "head" resources that were registered for the original page.
      * <p>
      * Note that JSF2.0 solves this issue by having components queue "system events" during the "build tree"
      * phase of rendering. Tomahawk could possibly provide a framework to allow its own classes to
      * do this for JSF1.2. But for JSF1.1 there is no "build tree" phase so this approach is the only
      * possibility.
      *   
      * @param context
      * @param myfacesCustomComponent
      * @throws IOException
      */
     public void addStyleLoaderHere(FacesContext context, Class myfacesCustomComponent) throws IOException
     {
         ResponseWriter writer = context.getResponseWriter();
 
         writer.startElement(HTML.LINK_ELEM, null);
         writer.writeAttribute(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.REL_ATTR, org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.STYLESHEET_VALUE, null);
         writer.writeAttribute(HTML.HREF_ATTR,
                 getResourceUri(context,
                         new StreamingResourceHandler(requestId + "/header.css"),
                         true), null);
         writer.writeAttribute(HTML.TYPE_ATTR, HTML.STYLE_TYPE_TEXT_CSS, null);
         writer.endElement(org.apache.myfaces.shared_tomahawk.renderkit.html.HTML.LINK_ELEM);
     }
 
     private String getResourceVirtualPath(ServletContext servletContext)
     {
         if(resourceVirtualPath == null)
         {
             resourceVirtualPath = servletContext.getInitParameter(MyfacesConfig.INIT_PARAM_RESOURCE_VIRTUAL_PATH);
 
             if(resourceVirtualPath == null)
             {
                 resourceVirtualPath = MyfacesConfig.INIT_PARAM_RESOURCE_VIRTUAL_PATH_DEFAULT;
             }
         }
 
         return resourceVirtualPath;
     }
 }