/*

  * $Id: ChainedDelegateRenderer.java 1306435 2012-03-28 15:39:11Z 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 java.util.ArrayList;

 import java.util.List;

 import org.apache.tiles.request.Request;

 /**

  * Renders an attribute that has no associated renderer using delegation to

  * other renderers.

  *

  * @version $Rev: 1306435 $ $Date: 2012-03-29 02:39:11 +1100 (Thu, 29 Mar 2012) $

  */

 public class ChainedDelegateRenderer implements Renderer {

     /**

      * The list of chained renderers.

      */

     private List<Renderer> renderers;

     /**

      * Constructor.

      */

     public ChainedDelegateRenderer() {

         renderers = new ArrayList<Renderer>();

     }

     /**

      * Adds an attribute renderer to the list. The first inserted this way, the

      * first is checked when rendering.

      *

      * @param renderer The renderer to add.

      */

     public void addAttributeRenderer(Renderer renderer) {

         renderers.add(renderer);

     }

     @Override

     public void render(String value, Request request) throws IOException {

         if (value == null) {

             throw new NullPointerException("The attribute value is null");

         }

         for (Renderer renderer : renderers) {

             if (renderer.isRenderable(value, request)) {

                 renderer.render(value, request);

                 return;

             }

         }

         throw new CannotRenderException("Cannot renderer value '" + value + "'");

     }

     /** {@inheritDoc} */

     public boolean isRenderable(String value, Request request) {

         for (Renderer renderer : renderers) {

             if (renderer.isRenderable(value, request)) {

                 return true;

             }

         }

         return false;

     }

 }