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 }