/*

  * $Id: VelocityRequest.java 1332186 2012-04-30 13:20:15Z nlebas $

  *

  * 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.request.velocity;

 import java.io.IOException;

 import java.io.PrintWriter;

 import java.io.Writer;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.List;

 import java.util.Map;

 import javax.servlet.RequestDispatcher;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import org.apache.tiles.request.AbstractViewRequest;

 import org.apache.tiles.request.ApplicationContext;

 import org.apache.tiles.request.DispatchRequest;

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

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

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

 import org.apache.velocity.context.Context;

 /**

  * The implementation of the Tiles request context specific for Velocity.

  *

  * @version $Rev: 1332186 $ $Date: 2012-04-30 23:20:15 +1000 (Mon, 30 Apr 2012) $

  */

 public class VelocityRequest extends AbstractViewRequest {

     /**

      * The native available scopes, in fact only "page".

      */

     private final List<String> scopes;

     /**

      * The Velocity current context.

      */

     private final Context ctx;

     /**

      * The writer to use to render the response. It may be null, if not necessary.

      */

     private Writer writer;

     /**

      * The map of the page scope.

      */

     private Map<String, Object> pageScope;

     /**

      * Factory method to create a Velocity request.

      *

      * @param applicationContext The application context.

      * @param request The request.

      * @param response The response.

      * @param velocityContext The Velocity context.

      * @param writer The writer to write into.

      * @return The request.

      */

     public static VelocityRequest createVelocityRequest(

             ApplicationContext applicationContext, HttpServletRequest request,

             HttpServletResponse response, Context velocityContext, Writer writer) {

         DispatchRequest servletRequest = new ServletRequest(

                 applicationContext, request, response);

         VelocityRequest velocityRequest = new VelocityRequest(

                 servletRequest, velocityContext, writer);

         return velocityRequest;

     }

     /**

      * Constructor.

      *

      * @param enclosedRequest The request that exposes non-Velocity specific properties

      * @param ctx The Velocity current context.

      * @param writer The writer to use to render the response. It may be null, if not necessary.

      */

     public VelocityRequest(

             DispatchRequest enclosedRequest, Context ctx, Writer writer) {

         super(enclosedRequest);

         List<String> scopes = new ArrayList<String>();

         scopes.addAll(enclosedRequest.getAvailableScopes());

         scopes.add("page");

         this.scopes = Collections.unmodifiableList(scopes);

         this.ctx = ctx;

         this.writer = writer;

     }

     @Override

     public List<String> getAvailableScopes() {

         return scopes;

     }

     /** {@inheritDoc} */

     @Override

     protected void doInclude(String path) throws IOException {

         ServletRequest servletRequest = org.apache.tiles.request.servlet.ServletUtil.getServletRequest(this);

         HttpServletRequest request = servletRequest.getRequest();

         HttpServletResponse response = servletRequest.getResponse();

         RequestDispatcher rd = request.getRequestDispatcher(path);

         if (rd == null) {

             throw new IOException("No request dispatcher returned for path '"

                     + path + "'");

         }

         PrintWriter printWriter = getPrintWriter();

         try {

             rd.include(request, new ExternalWriterHttpServletResponse(response,

                     printWriter));

         } catch (ServletException ex) {

             throw ServletUtil.wrapServletException(ex, "ServletException including path '"

                     + path + "'.");

         }

     }

     /** {@inheritDoc} */

     @Override

     public PrintWriter getPrintWriter() {

         if (writer == null) {

             throw new IllegalStateException(

                     "A writer-less Tiles request has been created, cannot return a PrintWriter");

         }

         if (writer instanceof PrintWriter) {

             return (PrintWriter) writer;

         }

         return new PrintWriter(writer);

     }

     /** {@inheritDoc} */

     @Override

     public Writer getWriter() {

         if (writer == null) {

             throw new IllegalStateException(

                     "A writer-less Tiles request has been created, cannot return a PrintWriter");

         }

         return writer;

     }

     /**

      * Returns the page scope.

      *

      * @return The page scope.

      */

     public Map<String, Object> getPageScope() {

         if (pageScope == null) {

             pageScope = new VelocityScopeMap(ctx);

         }

         return pageScope;

     }

     @Override

     public Map<String, Object> getContext(String scope) {

         return "page".equals(scope) ? getPageScope() : super.getContext(scope);

     }

 }