1   /*
    2    * $Id: VelocityTilesRequestContext.java 769961 2009-04-29 22:07:34Z apetrelli $
    3    *
    4    * Licensed to the Apache Software Foundation (ASF) under one
    5    * or more contributor license agreements.  See the NOTICE file
    6    * distributed with this work for additional information
    7    * regarding copyright ownership.  The ASF licenses this file
    8    * to you under the Apache License, Version 2.0 (the
    9    * "License"); you may not use this file except in compliance
   10    * with the License.  You may obtain a copy of the License at
   11    *
   12    * http://www.apache.org/licenses/LICENSE-2.0
   13    *
   14    * Unless required by applicable law or agreed to in writing,
   15    * software distributed under the License is distributed on an
   16    * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   17    * KIND, either express or implied.  See the License for the
   18    * specific language governing permissions and limitations
   19    * under the License.
   20    */
   21   
   22   package org.apache.tiles.velocity.context;
   23   
   24   import java.io.IOException;
   25   import java.io.PrintWriter;
   26   import java.io.Writer;
   27   
   28   import javax.servlet.RequestDispatcher;
   29   import javax.servlet.ServletException;
   30   import javax.servlet.http.HttpServletRequest;
   31   import javax.servlet.http.HttpServletResponse;
   32   
   33   import org.apache.tiles.context.TilesRequestContext;
   34   import org.apache.tiles.context.TilesRequestContextWrapper;
   35   import org.apache.tiles.servlet.context.ExternalWriterHttpServletResponse;
   36   import org.apache.tiles.servlet.context.ServletUtil;
   37   import org.apache.velocity.context.Context;
   38   
   39   /**
   40    * The implementation of the Tiles request context specific for Velocity.
   41    *
   42    * @version $Rev: 769961 $ $Date: 2009-04-30 00:07:34 +0200 (gio, 30 apr 2009) $
   43    * @since 2.2.0
   44    */
   45   public class VelocityTilesRequestContext extends TilesRequestContextWrapper {
   46   
   47       /**
   48        * The Velocity current context.
   49        */
   50       private final Context ctx;
   51   
   52       /**
   53        * The request objects.
   54        */
   55       private Object[] requestObjects;
   56   
   57       /**
   58        * The writer to use to render the response. It may be null, if not necessary.
   59        */
   60       private Writer writer;
   61   
   62       /**
   63        * Constructor.
   64        *
   65        * @param enclosedRequest The request that exposes non-Velocity specific properties
   66        * @param ctx The Velocity current context.
   67        * @param writer The writer to use to render the response. It may be null, if not necessary.
   68        * @since 2.2.0
   69        */
   70       public VelocityTilesRequestContext(
   71               TilesRequestContext enclosedRequest, Context ctx, Writer writer) {
   72           super(enclosedRequest);
   73           this.ctx = ctx;
   74           this.writer = writer;
   75       }
   76   
   77       /** {@inheritDoc} */
   78       public void dispatch(String path) throws IOException {
   79           include(path);
   80       }
   81   
   82       /** {@inheritDoc} */
   83       @Override
   84       public void include(String path) throws IOException {
   85           Object[] requestObjects = super.getRequestObjects();
   86           HttpServletRequest request = (HttpServletRequest) requestObjects[0];
   87           HttpServletResponse response = (HttpServletResponse) requestObjects[1];
   88           ServletUtil.setForceInclude(request, true);
   89           RequestDispatcher rd = request.getRequestDispatcher(path);
   90   
   91           if (rd == null) {
   92               throw new IOException("No request dispatcher returned for path '"
   93                       + path + "'");
   94           }
   95   
   96           PrintWriter printWriter = getPrintWriter();
   97           try {
   98               rd.include(request, new ExternalWriterHttpServletResponse(response,
   99                       printWriter));
  100           } catch (ServletException ex) {
  101               throw ServletUtil.wrapServletException(ex, "ServletException including path '"
  102                       + path + "'.");
  103           }
  104       }
  105   
  106       /** {@inheritDoc} */
  107       @Override
  108       public PrintWriter getPrintWriter() throws IOException {
  109           if (writer == null) {
  110               throw new IllegalStateException(
  111                       "A writer-less Tiles request has been created, cannot return a PrintWriter");
  112           }
  113           if (writer instanceof PrintWriter) {
  114               return (PrintWriter) writer;
  115           } else {
  116               return new PrintWriter(writer);
  117           }
  118       }
  119   
  120       /** {@inheritDoc} */
  121       @Override
  122       public Writer getWriter() throws IOException {
  123           if (writer == null) {
  124               throw new IllegalStateException(
  125                       "A writer-less Tiles request has been created, cannot return a PrintWriter");
  126           }
  127           return writer;
  128       }
  129   
  130       /** {@inheritDoc} */
  131       @Override
  132       public Object[] getRequestObjects() {
  133           if (requestObjects == null) {
  134               Object[] parentRequestObjects = super.getRequestObjects();
  135               if (writer == null) {
  136                   requestObjects = new Object[parentRequestObjects.length + 1];
  137               } else {
  138                   requestObjects = new Object[parentRequestObjects.length + 2];
  139               }
  140               requestObjects[0] = ctx;
  141               for (int i = 0; i < parentRequestObjects.length; i++) {
  142                   requestObjects[i + 1] = parentRequestObjects[i];
  143               }
  144               if (writer != null) {
  145                   requestObjects[parentRequestObjects.length + 1] = writer;
  146               }
  147           }
  148           return requestObjects;
  149       }
  150   }