/*

  * $Id: TilesDispatchServlet.java 995228 2010-09-08 19:50:09Z apetrelli $

  *

  * 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.web.util;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import org.apache.tiles.AttributeContext;

 import org.apache.tiles.TilesContainer;

 import org.apache.tiles.access.TilesAccess;

 import org.apache.tiles.request.ApplicationContext;

 import org.apache.tiles.request.Request;

 import org.apache.tiles.request.reflect.ClassUtil;

 import org.apache.tiles.request.servlet.ServletRequest;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 /**

  * Tiles dispatching servlet.  Used to invoke

  * a definition directly.

  */

 public class TilesDispatchServlet extends HttpServlet {

     /**

      * Init parameter to define the key of the container to use.

      *

      * @since 2.1.2

      */

     public static final String CONTAINER_KEY_INIT_PARAMETER =

         "org.apache.tiles.web.util.TilesDispatchServlet.CONTAINER_KEY";

     /**

      * The logging object.

      */

     private final Logger log = LoggerFactory

             .getLogger(TilesDispatchServlet.class);

     /**

      * The key under which the container is stored.

      */

     private String containerKey;

     /**

      * The object that will mutate the attribute context so that it uses

      * different attributes.

      */

     private AttributeContextMutator mutator;

     /** {@inheritDoc} */

     @Override

     public void init() throws ServletException {

         super.init();

         containerKey = getServletConfig().getInitParameter(

                 CONTAINER_KEY_INIT_PARAMETER);

         String temp = getInitParameter("mutator");

         if (temp != null) {

             try {

                 mutator = (AttributeContextMutator) ClassUtil.instantiate(temp);

             } catch (Exception e) {

                 throw new ServletException("Unable to instantiate specified context mutator.", e);

             }

         } else {

             mutator = new DefaultMutator();

         }

     }

     /** {@inheritDoc} */

     @Override

     protected void doGet(HttpServletRequest req, HttpServletResponse res) {

         ApplicationContext applicationContext = org.apache.tiles.request.servlet.ServletUtil

                 .getApplicationContext(getServletContext());

         Request request = new ServletRequest(applicationContext,

                 req, res);

         TilesContainer container = TilesAccess.getContainer(applicationContext,

                 containerKey);

         mutator.mutate(container.getAttributeContext(request), req);

         String definition = getDefinitionName(req);

         if (log.isDebugEnabled()) {

             log.info("Dispatching to tile '" + definition + "'");

         }

         container.render(definition, request);

     }

     /**

      * Returns the called definition name for the given request.

      *

      * @param request The request to parse.

      * @return The definition name to render.

      */

     protected String getDefinitionName(HttpServletRequest request) {

         String path = (String) request.getAttribute("javax.servlet.include.servlet_path");

         if (path == null) {

             path = request.getServletPath();

         }

         int start = path.startsWith("/") ? 1 : 0;

         int end = path.endsWith(".tiles") ? path.indexOf(".tiles") : path.length();

         return path.substring(start, end);

     }

     /** {@inheritDoc} */

     @Override

     protected void doPost(HttpServletRequest req, HttpServletResponse res) {

         log.info("Tiles dispatch request received. Redirecting POST to GET.");

         doGet(req, res);

     }

     /**

      * Default no-op mutator.

      */

     class DefaultMutator implements AttributeContextMutator {

         /** {@inheritDoc} */

         public void mutate(AttributeContext context, javax.servlet.ServletRequest request) {

             // noop;

         }

     }

 }