/*

  * 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.webapp;

 import java.util.Iterator;

 import javax.el.ExpressionFactory;

 import javax.faces.FactoryFinder;

 import javax.faces.context.ExternalContext;

 import javax.faces.event.PhaseListener;

 import javax.faces.lifecycle.LifecycleFactory;

 import javax.servlet.ServletContext;

 import javax.servlet.jsp.JspApplicationContext;

 import javax.servlet.jsp.JspFactory;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.apache.myfaces.config.RuntimeConfig;

 import org.apache.myfaces.el.ResolverForJSPInitializer;

 import org.apache.myfaces.el.unified.ELResolverBuilder;

 import org.apache.myfaces.el.unified.ResolverBuilderForJSP;

 import org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver;

 import org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.Scope;

 /**

  * Initializes MyFaces in a JSP 2.1 environment.

  *

  */

 public class Jsp21FacesInitializer extends AbstractFacesInitializer

 {

     /**

      * The logger instance for this class.

      */

     private static final Log log = LogFactory.getLog(Jsp21FacesInitializer.class);

     /**

      * Cached instance of the JspFactory to use.

      */

     private JspFactory jspFactory;

     @Override

     protected void initContainerIntegration(

             ServletContext servletContext, ExternalContext externalContext)

     {

         JspApplicationContext appCtx = 

             getJspFactory().getJspApplicationContext(servletContext);

         appCtx.addELContextListener(new FacesELContextListener());

         // check for user-specified ExpressionFactory

         ExpressionFactory expressionFactory = getUserDefinedExpressionFactory(externalContext);

         if (expressionFactory == null)

         {

             expressionFactory = appCtx.getExpressionFactory();

         }

         RuntimeConfig runtimeConfig =

             buildConfiguration(servletContext, externalContext, expressionFactory);

         // configure the el resolver for jsp

         configureResolverForJSP(appCtx, runtimeConfig);

     }

     protected JspFactory getJspFactory()

     {

         if (jspFactory == null) {

             // TODO: this Class.forName will be removed when Tomcat fixes a bug

             // also, we should then be able to remove jasper.jar from the deployment

             try {

                 Class.forName("org.apache.jasper.compiler.JspRuntimeContext");

             } catch (ClassNotFoundException e) {

                 ; // ignore

             } catch (Exception ex) {

                 log.debug("An unexpected exception occured "

                         + "while loading the JspRuntimeContext.", ex);

             }

             jspFactory = JspFactory.getDefaultFactory();

         }

         return jspFactory;

     }

     /**

      * Sets the JspFactory to use. Currently, this method just simplifies

      * testing.

      * 

      * @param jspFactory

      *            the JspFactory to use

      */

     protected void setJspFactory(JspFactory jspFactory)

     {

         this.jspFactory = jspFactory;

     }

     /**

      * Register a phase listener to every lifecycle. This listener will lazy fill the el resolver for jsp as soon as the

      * first lifecycle is executed. This is necessarry to allow a faces application further setup after MyFaces has been

      * initialized. When the first request is processed no further configuation of the el resolvers is allowed.

      * 

      * @param appCtx

      * @param runtimeConfig

      */

     private void configureResolverForJSP(JspApplicationContext appCtx, RuntimeConfig runtimeConfig)

     {

         FacesCompositeELResolver facesCompositeELResolver = new FacesCompositeELResolver(Scope.JSP);

         appCtx.addELResolver(facesCompositeELResolver);

         PhaseListener resolverForJSPInitializer = new ResolverForJSPInitializer(

                 createResolverBuilderForJSP(runtimeConfig), facesCompositeELResolver);

         LifecycleFactory factory = (LifecycleFactory) FactoryFinder.getFactory(FactoryFinder.LIFECYCLE_FACTORY);

         for (Iterator<String> iter = factory.getLifecycleIds(); iter.hasNext();)

         {

             factory.getLifecycle(iter.next()).addPhaseListener(resolverForJSPInitializer);

         }

     }

     protected ELResolverBuilder createResolverBuilderForJSP(RuntimeConfig runtimeConfig)

     {

         return new ResolverBuilderForJSP(runtimeConfig);

     }

 }