/*

  * $Id: JspExpressionFactoryFactory.java 1229087 2012-01-09 10:35:14Z mck $

  *

  * 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.tiles.el;

 import javax.el.ExpressionFactory;

 import javax.servlet.ServletContext;

 import javax.servlet.jsp.JspFactory;

 import org.apache.tiles.request.ApplicationContext;

 import org.apache.tiles.request.ApplicationContextAware;

 /**

  * Uses the JSP 2.1 {@link ExpressionFactory} to be used in Tiles.

  *

  * @version $Rev: 1229087 $ $Date: 2012-01-09 21:35:14 +1100 (Mon, 09 Jan 2012) $

  * @since 2.2.1

  */

 public class JspExpressionFactoryFactory implements ExpressionFactoryFactory,

         ApplicationContextAware {

     /**

      * The servlet context.

      *

      * @since 2.2.1

      */

     protected ServletContext servletContext;

     /** {@inheritDoc} */

     public void setApplicationContext(ApplicationContext applicationContext) {

         Object context = applicationContext.getContext();

         if (context instanceof ServletContext) {

             this.servletContext = (ServletContext) context;

         } else {

             throw new IllegalArgumentException(

                     "The application context does not hold an instance of "

                     + "ServletContext, consider using JuelExpressionFactoryFactory");

         }

     }

     /** {@inheritDoc} */

     public ExpressionFactory getExpressionFactory() {

         return JspFactory.getDefaultFactory().getJspApplicationContext(

                 servletContext).getExpressionFactory();

     }

 }