| /* |
| * $Id$ |
| * |
| * 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.Collections; |
| import java.util.List; |
| |
| import org.apache.tiles.request.Request; |
| |
| /** |
| * Provides a Publisher-Subscriber implementation around the provided renderer to delegate to. |
| * |
| * @version $Rev: 1035784 $ $Date: 2010-11-16 20:24:12 +0000 (Tue, 16 Nov 2010) $ |
| */ |
| public class PublisherRenderer implements Renderer { |
| |
| public interface RendererListener{ |
| /** Called before the delegate's render method is called. */ |
| void start(String template, Request request) throws IOException; |
| /** Called after the delegate's render method is called. */ |
| void end(String template, Request request) throws IOException; |
| /** If the delegate render method throws an IOException it is passed through this. */ |
| void handleIOException(IOException ex, Request request) throws IOException; |
| } |
| |
| private final Renderer renderer; |
| private final List<RendererListener> listeners = new ArrayList<RendererListener>(); |
| private final List<RendererListener> listenersReversed = new ArrayList<RendererListener>(); |
| |
| public PublisherRenderer(Renderer renderer){ |
| this.renderer = renderer; |
| } |
| |
| @Override |
| public void render(String path, Request request) throws IOException { |
| if (path == null) { |
| throw new CannotRenderException("Cannot dispatch a null path"); |
| } |
| try{ |
| for(RendererListener listener : listeners){ |
| listener.start(path, request); |
| } |
| renderer.render(path, request); |
| }catch(IOException ex){ |
| handleIOException(ex, request); |
| }finally{ |
| for(RendererListener wrapper : listenersReversed){ |
| wrapper.end(path, request); |
| } |
| } |
| } |
| |
| @Override |
| public boolean isRenderable(String path, Request request) { |
| return renderer.isRenderable(path, request); |
| } |
| |
| public void addListener(RendererListener listener){ |
| listeners.add(listener); |
| listenersReversed.clear(); |
| listenersReversed.addAll(listeners); |
| Collections.reverse(listenersReversed); |
| } |
| |
| private void handleIOException(IOException exception, Request request) throws IOException{ |
| IOException ex = exception; |
| boolean throwIt = listeners.isEmpty(); |
| for(RendererListener listener : listenersReversed){ |
| try{ |
| listener.handleIOException(ex, request); |
| throwIt = false; |
| }catch(IOException newEx){ |
| ex = newEx; |
| throwIt = true; |
| } |
| } |
| if(throwIt){ |
| throw ex; |
| } |
| } |
| } |