1 /*
2 * $Id: VelocityRenderer.java 1306435 2012-03-28 15:39:11Z nlebas $
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.request.velocity.render;
23
24 import java.io.IOException;
25
26 import org.apache.tiles.request.Request;
27 import org.apache.tiles.request.render.CannotRenderException;
28 import org.apache.tiles.request.render.Renderer;
29 import org.apache.tiles.request.servlet.ServletRequest;
30 import org.apache.tiles.request.servlet.ServletUtil;
31 import org.apache.velocity.Template;
32 import org.apache.velocity.context.Context;
33 import org.apache.velocity.tools.view.VelocityView;
34
35 /**
36 * Attribute renderer for rendering Velocity templates as attributes. <br>
37 * It is available only to Servlet-based environment.<br>
38 * It uses {@link VelocityView} to render the response.<br>
39 * To initialize it correctly, call {@link #setParameter(String, String)} for
40 * all the parameters that you want to set, and then call {@link #commit()}.
41 *
42 * @version $Rev: 1306435 $ $Date: 2012-03-29 02:39:11 +1100 (Thu, 29 Mar 2012) $
43 */
44 public class VelocityRenderer implements Renderer {
45
46 /**
47 * The VelocityView object to use.
48 */
49 private VelocityView velocityView;
50
51 /**
52 * Constructor.
53 *
54 * @param velocityView The Velocity view manager.
55 */
56 public VelocityRenderer(VelocityView velocityView) {
57 this.velocityView = velocityView;
58 }
59
60 /** {@inheritDoc} */
61 @Override
62 public void render(String path, Request request) throws IOException {
63 if (path == null) {
64 throw new CannotRenderException("Cannot dispatch a null path");
65 }
66
67 ServletRequest servletRequest = ServletUtil.getServletRequest(request);
68 // then get a context
69 Context context = velocityView.createContext(servletRequest
70 .getRequest(), servletRequest.getResponse());
71
72 // get the template
73 Template template = velocityView.getTemplate((String) path);
74
75 // merge the template and context into the writer
76 velocityView.merge(template, context, request.getWriter());
77 }
78
79 /** {@inheritDoc} */
80 public boolean isRenderable(String path, Request request) {
81 return path != null && path.startsWith("/") && path.endsWith(".vm");
82 }
83 }