1 /* 2 * Copyright 2004 Sun Microsystems, Inc. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 * 16 */ 17 package com.sun.syndication.io; 18 19 import com.sun.syndication.feed.WireFeed; 20 import com.sun.syndication.io.impl.FeedGenerators; 21 import org.jdom.Document; 22 import org.jdom.JDOMException; 23 import org.jdom.output.DOMOutputter; 24 import org.jdom.output.Format; 25 import org.jdom.output.XMLOutputter; 26 27 import java.io.IOException; 28 import java.io.Writer; 29 import java.io.File; 30 import java.io.FileWriter; 31 import java.util.List; 32 33 /** 34 * Generates an XML document (String, File, OutputStream, Writer, W3C DOM document or JDOM document) 35 * out of an WireFeed (RSS/Atom). 36 * <p> 37 * It generates all flavors of RSS (0.90, 0.91, 0.92, 0.93, 0.94, 1.0 and 2.0) and 38 * Atom 0.3 feeds. Generators are plugable (they must implement the ModuleParser interface). 39 * <p> 40 * @author Alejandro Abdelnur 41 * 42 */ 43 public class WireFeedOutput { 44 private final static FeedGenerators GENERATORS = new FeedGenerators(); 45 46 /** 47 * Returns the list of supported output feed types. 48 * <p> 49 * @see WireFeed for details on the format of these strings. 50 * <p> 51 * @return a list of String elements with the supported output feed types. 52 * 53 */ 54 public static List getSupportedFeedTypes() { 55 return GENERATORS.getSupportedFeedTypes(); 56 } 57 58 /** 59 * Creates a FeedOuput instance. 60 * <p> 61 * 62 */ 63 public WireFeedOutput() { 64 } 65 66 /** 67 * Creates a String with the XML representation for the given WireFeed. 68 * <p> 69 * If the feed encoding is not NULL, it will be used in the XML prolog encoding attribute. It is the responsibility 70 * of the developer to ensure that if the String is written to a character stream the stream charset is the same as 71 * the feed encoding property. 72 * <p> 73 * NOTE: This method delages to the 'Document WireFeedOutput#outputJDom(WireFeed)'. 74 * <p> 75 * @param feed Abstract feed to create XML representation from. The type of the WireFeed must match 76 * the type given to the FeedOuptut constructor. 77 * @return a String with the XML representation for the given WireFeed. 78 * @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed don't match. 79 * @throws FeedException thrown if the XML representation for the feed could not be created. 80 * 81 */ 82 public String outputString(WireFeed feed) throws IllegalArgumentException,FeedException { 83 Document doc = outputJDom(feed); 84 String encoding = feed.getEncoding(); 85 Format format = Format.getPrettyFormat(); 86 if (encoding!=null) { 87 format.setEncoding(encoding); 88 } 89 XMLOutputter outputter = new XMLOutputter(format); 90 return outputter.outputString(doc); 91 } 92 93 /** 94 * Creates a File containing with the XML representation for the given WireFeed. 95 * <p> 96 * If the feed encoding is not NULL, it will be used in the XML prolog encoding attribute. The platform 97 * default charset encoding is used to write the feed to the file. It is the responsibility 98 * of the developer to ensure the feed encoding is set to the platform charset encoding. 99 * <p> 100 * NOTE: This method delages to the 'Document WireFeedOutput#outputJDom(WireFeed)'. 101 * <p> 102 * @param feed Abstract feed to create XML representation from. The type of the WireFeed must match 103 * the type given to the FeedOuptut constructor. 104 * @param file the file where to write the XML representation for the given WireFeed. 105 * @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed don't match. 106 * @throws IOException thrown if there was some problem writing to the File. 107 * @throws FeedException thrown if the XML representation for the feed could not be created. 108 * 109 */ 110 public void output(WireFeed feed,File file) throws IllegalArgumentException,IOException,FeedException { 111 Writer writer = new FileWriter(file); 112 output(feed,writer); 113 writer.close(); 114 } 115 116 /** 117 * Writes to an Writer the XML representation for the given WireFeed. 118 * <p> 119 * If the feed encoding is not NULL, it will be used in the XML prolog encoding attribute. It is the responsibility 120 * of the developer to ensure the Writer instance is using the same charset encoding. 121 * <p> 122 * NOTE: This method delages to the 'Document WireFeedOutput#outputJDom(WireFeed)'. 123 * <p> 124 * @param feed Abstract feed to create XML representation from. The type of the WireFeed must match 125 * the type given to the FeedOuptut constructor. 126 * @param writer Writer to write the XML representation for the given WireFeed. 127 * @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed don't match. 128 * @throws IOException thrown if there was some problem writing to the Writer. 129 * @throws FeedException thrown if the XML representation for the feed could not be created. 130 * 131 */ 132 public void output(WireFeed feed,Writer writer) throws IllegalArgumentException,IOException, FeedException { 133 Document doc = outputJDom(feed); 134 String encoding = feed.getEncoding(); 135 Format format = Format.getPrettyFormat(); 136 if (encoding!=null) { 137 format.setEncoding(encoding); 138 } 139 XMLOutputter outputter = new XMLOutputter(format); 140 outputter.output(doc,writer); 141 } 142 143 /** 144 * Creates a W3C DOM document for the given WireFeed. 145 * <p> 146 * This method does not use the feed encoding property. 147 * <p> 148 * NOTE: This method delages to the 'Document WireFeedOutput#outputJDom(WireFeed)'. 149 * <p> 150 * @param feed Abstract feed to create W3C DOM document from. The type of the WireFeed must match 151 * the type given to the FeedOuptut constructor. 152 * @return the W3C DOM document for the given WireFeed. 153 * @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed don't match. 154 * @throws FeedException thrown if the W3C DOM document for the feed could not be created. 155 * 156 */ 157 public org.w3c.dom.Document outputW3CDom(WireFeed feed) throws IllegalArgumentException,FeedException { 158 Document doc = outputJDom(feed); 159 DOMOutputter outputter = new DOMOutputter(); 160 try { 161 return outputter.output(doc); 162 } 163 catch (JDOMException jdomEx) { 164 throw new FeedException("Could not create DOM",jdomEx); 165 } 166 } 167 168 /** 169 * Creates a JDOM document for the given WireFeed. 170 * <p> 171 * This method does not use the feed encoding property. 172 * <p> 173 * NOTE: All other output methods delegate to this method. 174 * <p> 175 * @param feed Abstract feed to create JDOM document from. The type of the WireFeed must match 176 * the type given to the FeedOuptut constructor. 177 * @return the JDOM document for the given WireFeed. 178 * @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed don't match. 179 * @throws FeedException thrown if the JDOM document for the feed could not be created. 180 * 181 */ 182 public Document outputJDom(WireFeed feed) throws IllegalArgumentException,FeedException { 183 String type = feed.getFeedType(); 184 WireFeedGenerator generator = GENERATORS.getGenerator(type); 185 if (generator==null) { 186 throw new IllegalArgumentException("Invalid feed type ["+type+"]"); 187 } 188 189 if (!generator.getType().equals(type)) { 190 throw new IllegalArgumentException("WireFeedOutput type["+type+"] and WireFeed type ["+ 191 type+"] don't match"); 192 } 193 return generator.generate(feed); 194 } 195 196 }