/*
    * $Id: DispatchRenderer.java 1375743 2012-08-21 20:05:58Z 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.render;
  
  import java.io.IOException;
  
  import org.apache.tiles.request.Request;
  import org.apache.tiles.request.DispatchRequest;
  import org.apache.tiles.request.RequestWrapper;
  
  /**
   * Renders an attribute that contains a reference to a template.
   *
   * @version $Rev: 1375743 $ $Date: 2012-08-22 06:05:58 +1000 (Wed, 22 Aug 2012) $
   */
  public class DispatchRenderer implements Renderer {
  
      /** {@inheritDoc} */
      @Override
      public void render(String path, Request request) throws IOException {
          if (path == null) {
              throw new CannotRenderException("Cannot dispatch a null path");
          }
          DispatchRequest dispatchRequest = getDispatchRequest(request);
          if (dispatchRequest == null) {
              throw new CannotRenderException("Cannot dispatch outside of a web environment");
          }
  
          dispatchRequest.dispatch(path);
      }
  
      /** {@inheritDoc} */
      public boolean isRenderable(String path, Request request) {
          return path != null && getDispatchRequest(request) != null && path.startsWith("/");
      }
  
      private DispatchRequest getDispatchRequest(Request request) {
          Request result = request;
          while (!(result instanceof DispatchRequest) && result instanceof RequestWrapper) {
              result = ((RequestWrapper) result).getWrappedRequest();
          }
          if (!(result instanceof DispatchRequest)) {
              result = null;
          }
          return (DispatchRequest) result;
      }
  }