1 /*
2 * $Id: ChainedDelegateRenderer.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 package org.apache.tiles.request.render;
22
23 import java.io.IOException;
24 import java.util.ArrayList;
25 import java.util.List;
26
27 import org.apache.tiles.request.Request;
28
29 /**
30 * Renders an attribute that has no associated renderer using delegation to
31 * other renderers.
32 *
33 * @version $Rev: 1306435 $ $Date: 2012-03-29 02:39:11 +1100 (Thu, 29 Mar 2012) $
34 */
35 public class ChainedDelegateRenderer implements Renderer {
36
37 /**
38 * The list of chained renderers.
39 */
40 private List<Renderer> renderers;
41
42 /**
43 * Constructor.
44 */
45 public ChainedDelegateRenderer() {
46 renderers = new ArrayList<Renderer>();
47 }
48
49 /**
50 * Adds an attribute renderer to the list. The first inserted this way, the
51 * first is checked when rendering.
52 *
53 * @param renderer The renderer to add.
54 */
55 public void addAttributeRenderer(Renderer renderer) {
56 renderers.add(renderer);
57 }
58
59
60 @Override
61 public void render(String value, Request request) throws IOException {
62 if (value == null) {
63 throw new NullPointerException("The attribute value is null");
64 }
65
66 for (Renderer renderer : renderers) {
67 if (renderer.isRenderable(value, request)) {
68 renderer.render(value, request);
69 return;
70 }
71 }
72
73 throw new CannotRenderException("Cannot renderer value '" + value + "'");
74 }
75
76 /** {@inheritDoc} */
77 public boolean isRenderable(String value, Request request) {
78 for (Renderer renderer : renderers) {
79 if (renderer.isRenderable(value, request)) {
80 return true;
81 }
82 }
83 return false;
84 }
85 }