/*

  * 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.context;

 import java.lang.reflect.Field;

 import javax.faces.FacesException;

 import javax.faces.context.ExternalContext;

 import javax.faces.context.FacesContext;

 import javax.faces.context.FacesContextFactory;

 import javax.faces.lifecycle.Lifecycle;

 import javax.servlet.ServletContext;

 import javax.servlet.ServletRequest;

 import javax.servlet.ServletResponse;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.apache.myfaces.context.servlet.FacesContextImpl;

 import org.apache.myfaces.context.servlet.ServletExternalContextImpl;

 /**

  * DOCUMENT ME!

  * @author Manfred Geiler (latest modification by $Author: lu4242 $)

  * @version $Revision: 827879 $ $Date: 2009-10-20 22:10:03 -0500 (Tue, 20 Oct 2009) $

  */

 public class FacesContextFactoryImpl

         extends FacesContextFactory implements ReleaseableFacesContextFactory

 {

     private static final Log log = LogFactory.getLog(FacesContextFactoryImpl.class);

     /**

      * This var is assigned as the same as javax.faces.context.ExternalContext._firstInstance,

      * and since it is a static reference and does not change, we can cache it here safely.

      */

     private final ThreadLocal<ExternalContext> _firstExternalContextInstance;

     @SuppressWarnings("unchecked")

     public FacesContextFactoryImpl()

     {

         super();

         ThreadLocal<ExternalContext> firstExternalContextInstance = null;

         try

         {

             Field externalContextFirstInstance = ExternalContext.class.getDeclaredField("_firstInstance");

             externalContextFirstInstance.setAccessible(true);

             if (externalContextFirstInstance != null)

             {

                 if (firstExternalContextInstance == null)

                 {

                     firstExternalContextInstance = 

                         (ThreadLocal<ExternalContext>) externalContextFirstInstance.get(null);

                 }

             }

         }

         catch (SecurityException e)

         {

             // It could happen, but we can ignore it.

             if (log.isDebugEnabled())

                 log.debug("Cannot access private field _firstInstance from ExternalContext ",e);

         }

         catch (Exception e)

         {

             //It should not happen if we have only myfaces on classpath

             if (log.isDebugEnabled())

                 log.debug("Cannot found private field _firstInstance from ExternalContext ",e);

         }

         _firstExternalContextInstance = firstExternalContextInstance;

     }

     public FacesContext getFacesContext(Object context,

                                         Object request,

                                         Object response,

                                         Lifecycle lifecycle)

             throws FacesException

     {

         if (context == null) {

             throw new NullPointerException("context");

         }

         if (request == null) {

             throw new NullPointerException("request");

         }

         if (response == null) {

             throw new NullPointerException("response");

         }

         if (lifecycle == null) {

             throw new NullPointerException("lifecycle");

         }

         FacesContext facesContext = null;

         //We need this instance to be set later.

         ReleaseableExternalContext externalContext = new ServletExternalContextImpl((ServletContext)context,

                     (ServletRequest) request, (ServletResponse) response);

         // MyfacesGenericPortlet was replaced by jsr 301 portlet bridge,

         // and the bundled inside myfaces 1.2 sources does not work because

         // there was changes from 1.1 to 1.2 (viewhandler), so we 

         // can comment this code.

         // Note all portlet code was removed in version 2.0, but it is

         // not necessary to remove from this branch.

         // else if (context instanceof PortletContext)

         //{

         //    externalContext = new PortletExternalContextImpl(context,

         //            request, response);

         //}

         facesContext = new FacesContextImpl(externalContext,this);

         if (facesContext != null)

         {

             if (_firstExternalContextInstance != null)

             {

                 // Initialize the firstExternalContext that old jsf 1.1 of 

                 // ExternalContext should fall when call jsf 1.2 methods.

                 _firstExternalContextInstance.set((ExternalContext) externalContext);

             }            

             return facesContext;

         }

         throw new FacesException("Unsupported context type " + context.getClass().getName());

     }

     public void release()

     {

         if (_firstExternalContextInstance != null)

         {

             _firstExternalContextInstance.remove();

         }

     }    

 }