/*
* Copyright 2004 Sun Microsystems, Inc.
*
* Licensed 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 com.sun.syndication.io;
import com.sun.syndication.feed.WireFeed;
import com.sun.syndication.io.impl.FeedGenerators;
import org.jdom.Document;
import org.jdom.JDOMException;
import org.jdom.output.DOMOutputter;
import org.jdom.output.Format;
import org.jdom.output.XMLOutputter;
import java.io.IOException;
import java.io.Writer;
import java.io.File;
import java.io.FileWriter;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;
/**
* Generates an XML document (String, File, OutputStream, Writer, W3C DOM document or JDOM document)
* out of an WireFeed (RSS/Atom).
* <p>
* It generates all flavors of RSS (0.90, 0.91, 0.92, 0.93, 0.94, 1.0 and 2.0) and
* Atom 0.3 feeds. Generators are plugable (they must implement the ModuleParser interface).
* <p>
* @author Alejandro Abdelnur
*
*/
public class WireFeedOutput {
private static Map clMap = new WeakHashMap();
private static FeedGenerators getFeedGenerators() {
synchronized(WireFeedOutput.class) {
FeedGenerators generators = (FeedGenerators)
clMap.get(Thread.currentThread().getContextClassLoader());
if (generators == null) {
generators = new FeedGenerators();
clMap.put(Thread.currentThread().getContextClassLoader(), generators);
}
return generators;
}
}
/**
* Returns the list of supported output feed types.
* <p>
* @see WireFeed for details on the format of these strings.
* <p>
* @return a list of String elements with the supported output feed types.
*
*/
public static List getSupportedFeedTypes() {
return getFeedGenerators().getSupportedFeedTypes();
}
/**
* Creates a FeedOuput instance.
* <p>
*
*/
public WireFeedOutput() {
}
/**
* Creates a String with the XML representation for the given WireFeed.
* <p>
* If the feed encoding is not NULL, it will be used in the XML prolog encoding attribute. It is the responsibility
* of the developer to ensure that if the String is written to a character stream the stream charset is the same as
* the feed encoding property.
* <p>
* NOTE: This method delages to the 'Document WireFeedOutput#outputJDom(WireFeed)'.
* <p>
* @param feed Abstract feed to create XML representation from. The type of the WireFeed must match
* the type given to the FeedOuptut constructor.
* @return a String with the XML representation for the given WireFeed.
* @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed don't match.
* @throws FeedException thrown if the XML representation for the feed could not be created.
*
*/
public String outputString(WireFeed feed) throws IllegalArgumentException,FeedException {
Document doc = outputJDom(feed);
String encoding = feed.getEncoding();
Format format = Format.getPrettyFormat();
if (encoding!=null) {
format.setEncoding(encoding);
}
XMLOutputter outputter = new XMLOutputter(format);
return outputter.outputString(doc);
}
/**
* Creates a File containing with the XML representation for the given WireFeed.
* <p>
* If the feed encoding is not NULL, it will be used in the XML prolog encoding attribute. The platform
* default charset encoding is used to write the feed to the file. It is the responsibility
* of the developer to ensure the feed encoding is set to the platform charset encoding.
* <p>
* NOTE: This method delages to the 'Document WireFeedOutput#outputJDom(WireFeed)'.
* <p>
* @param feed Abstract feed to create XML representation from. The type of the WireFeed must match
* the type given to the FeedOuptut constructor.
* @param file the file where to write the XML representation for the given WireFeed.
* @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed don't match.
* @throws IOException thrown if there was some problem writing to the File.
* @throws FeedException thrown if the XML representation for the feed could not be created.
*
*/
public void output(WireFeed feed,File file) throws IllegalArgumentException,IOException,FeedException {
Writer writer = new FileWriter(file);
output(feed,writer);
writer.close();
}
/**
* Writes to an Writer the XML representation for the given WireFeed.
* <p>
* If the feed encoding is not NULL, it will be used in the XML prolog encoding attribute. It is the responsibility
* of the developer to ensure the Writer instance is using the same charset encoding.
* <p>
* NOTE: This method delages to the 'Document WireFeedOutput#outputJDom(WireFeed)'.
* <p>
* @param feed Abstract feed to create XML representation from. The type of the WireFeed must match
* the type given to the FeedOuptut constructor.
* @param writer Writer to write the XML representation for the given WireFeed.
* @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed don't match.
* @throws IOException thrown if there was some problem writing to the Writer.
* @throws FeedException thrown if the XML representation for the feed could not be created.
*
*/
public void output(WireFeed feed,Writer writer) throws IllegalArgumentException,IOException, FeedException {
Document doc = outputJDom(feed);
String encoding = feed.getEncoding();
Format format = Format.getPrettyFormat();
if (encoding!=null) {
format.setEncoding(encoding);
}
XMLOutputter outputter = new XMLOutputter(format);
outputter.output(doc,writer);
}
/**
* Creates a W3C DOM document for the given WireFeed.
* <p>
* This method does not use the feed encoding property.
* <p>
* NOTE: This method delages to the 'Document WireFeedOutput#outputJDom(WireFeed)'.
* <p>
* @param feed Abstract feed to create W3C DOM document from. The type of the WireFeed must match
* the type given to the FeedOuptut constructor.
* @return the W3C DOM document for the given WireFeed.
* @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed don't match.
* @throws FeedException thrown if the W3C DOM document for the feed could not be created.
*
*/
public org.w3c.dom.Document outputW3CDom(WireFeed feed) throws IllegalArgumentException,FeedException {
Document doc = outputJDom(feed);
DOMOutputter outputter = new DOMOutputter();
try {
return outputter.output(doc);
}
catch (JDOMException jdomEx) {
throw new FeedException("Could not create DOM",jdomEx);
}
}
/**
* Creates a JDOM document for the given WireFeed.
* <p>
* This method does not use the feed encoding property.
* <p>
* NOTE: All other output methods delegate to this method.
* <p>
* @param feed Abstract feed to create JDOM document from. The type of the WireFeed must match
* the type given to the FeedOuptut constructor.
* @return the JDOM document for the given WireFeed.
* @throws IllegalArgumentException thrown if the feed type of the WireFeedOutput and WireFeed don't match.
* @throws FeedException thrown if the JDOM document for the feed could not be created.
*
*/
public Document outputJDom(WireFeed feed) throws IllegalArgumentException,FeedException {
String type = feed.getFeedType();
WireFeedGenerator generator = getFeedGenerators().getGenerator(type);
if (generator==null) {
throw new IllegalArgumentException("Invalid feed type ["+type+"]");
}
if (!generator.getType().equals(type)) {
throw new IllegalArgumentException("WireFeedOutput type["+type+"] and WireFeed type ["+
type+"] don't match");
}
return generator.generate(feed);
}
}