001/* 002 * Copyright 2002-2017 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.web.servlet.view.feed; 018 019import java.util.List; 020import java.util.Map; 021import javax.servlet.http.HttpServletRequest; 022import javax.servlet.http.HttpServletResponse; 023 024import com.rometools.rome.feed.rss.Channel; 025import com.rometools.rome.feed.rss.Item; 026 027import org.springframework.http.MediaType; 028 029/** 030 * Abstract superclass for RSS Feed views, using the 031 * <a href="https://github.com/rometools/rome">ROME</a> package. 032 * 033 * <p>><b>NOTE: As of Spring 4.1, this is based on the {@code com.rometools} 034 * variant of ROME, version 1.5. Please upgrade your build dependency.</b> 035 * 036 * <p>Application-specific view classes will extend this class. 037 * The view will be held in the subclass itself, not in a template. 038 * Main entry points are the {@link #buildFeedMetadata} and {@link #buildFeedItems}. 039 * 040 * <p>Thanks to Jettro Coenradie and Sergio Bossa for the original feed view prototype! 041 * 042 * @author Arjen Poutsma 043 * @author Juergen Hoeller 044 * @since 3.0 045 * @see #buildFeedMetadata 046 * @see #buildFeedItems 047 */ 048public abstract class AbstractRssFeedView extends AbstractFeedView<Channel> { 049 050 public AbstractRssFeedView() { 051 setContentType(MediaType.APPLICATION_RSS_XML_VALUE); 052 } 053 054 055 /** 056 * Create a new Channel instance to hold the entries. 057 * <p>By default returns an RSS 2.0 channel, but the subclass can specify any channel. 058 */ 059 @Override 060 protected Channel newFeed() { 061 return new Channel("rss_2.0"); 062 } 063 064 /** 065 * Invokes {@link #buildFeedItems(Map, HttpServletRequest, HttpServletResponse)} 066 * to get a list of feed items. 067 */ 068 @Override 069 protected final void buildFeedEntries(Map<String, Object> model, Channel channel, 070 HttpServletRequest request, HttpServletResponse response) throws Exception { 071 072 List<Item> items = buildFeedItems(model, request, response); 073 channel.setItems(items); 074 } 075 076 /** 077 * Subclasses must implement this method to build feed items, given the model. 078 * <p>Note that the passed-in HTTP response is just supposed to be used for 079 * setting cookies or other HTTP headers. The built feed itself will automatically 080 * get written to the response after this method returns. 081 * @param model the model Map 082 * @param request in case we need locale etc. Shouldn't look at attributes. 083 * @param response in case we need to set cookies. Shouldn't write to it. 084 * @return the feed items to be added to the feed 085 * @throws Exception any exception that occurred during document building 086 * @see Item 087 */ 088 protected abstract List<Item> buildFeedItems( 089 Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) 090 throws Exception; 091 092}