Java tutorial
/* * 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.impl; import java.io.StringReader; import java.util.Iterator; import java.util.List; import org.jdom2.Attribute; import org.jdom2.Document; import org.jdom2.Element; import org.jdom2.Namespace; import org.jdom2.input.SAXBuilder; import com.sun.syndication.feed.WireFeed; import com.sun.syndication.feed.atom.Category; import com.sun.syndication.feed.atom.Content; import com.sun.syndication.feed.atom.Entry; import com.sun.syndication.feed.atom.Feed; import com.sun.syndication.feed.atom.Generator; import com.sun.syndication.feed.atom.Link; import com.sun.syndication.feed.atom.Person; import com.sun.syndication.io.FeedException; import com.sun.syndication.io.WireFeedOutput; import java.io.IOException; import java.io.Writer; import java.util.ArrayList; import org.jdom2.output.XMLOutputter; /** * Feed Generator for Atom * <p/> * * @author Elaine Chien * @author Dave Johnson (updated for Atom 1.0) * */ public class Atom10Generator extends BaseWireFeedGenerator { private static final String ATOM_10_URI = "http://www.w3.org/2005/Atom"; private static final Namespace ATOM_NS = Namespace.getNamespace(ATOM_10_URI); private String _version; public Atom10Generator() { this("atom_1.0", "1.0"); } protected Atom10Generator(String type, String version) { super(type); _version = version; } protected String getVersion() { return _version; } protected Namespace getFeedNamespace() { return ATOM_NS; } public Document generate(WireFeed wFeed) throws FeedException { Feed feed = (Feed) wFeed; Element root = createRootElement(feed); populateFeed(feed, root); purgeUnusedNamespaceDeclarations(root); return createDocument(root); } protected Document createDocument(Element root) { return new Document(root); } protected Element createRootElement(Feed feed) { Element root = new Element("feed", getFeedNamespace()); root.addNamespaceDeclaration(getFeedNamespace()); //Attribute version = new Attribute("version", getVersion()); //root.setAttribute(version); if (feed.getXmlBase() != null) { root.setAttribute("base", feed.getXmlBase(), Namespace.XML_NAMESPACE); } generateModuleNamespaceDefs(root); return root; } protected void populateFeed(Feed feed, Element parent) throws FeedException { addFeed(feed, parent); addEntries(feed, parent); } protected void addFeed(Feed feed, Element parent) throws FeedException { Element eFeed = parent; populateFeedHeader(feed, eFeed); generateForeignMarkup(eFeed, (List) feed.getForeignMarkup()); checkFeedHeaderConstraints(eFeed); generateFeedModules(feed.getModules(), eFeed); } protected void addEntries(Feed feed, Element parent) throws FeedException { List items = feed.getEntries(); for (int i = 0; i < items.size(); i++) { addEntry((Entry) items.get(i), parent); } checkEntriesConstraints(parent); } protected void addEntry(Entry entry, Element parent) throws FeedException { Element eEntry = new Element("entry", getFeedNamespace()); if (entry.getXmlBase() != null) { eEntry.setAttribute("base", entry.getXmlBase(), Namespace.XML_NAMESPACE); } populateEntry(entry, eEntry); generateForeignMarkup(eEntry, (List) entry.getForeignMarkup()); checkEntryConstraints(eEntry); generateItemModules(entry.getModules(), eEntry); parent.addContent(eEntry); } protected void populateFeedHeader(Feed feed, Element eFeed) throws FeedException { if (feed.getTitleEx() != null) { Element titleElement = new Element("title", getFeedNamespace()); fillContentElement(titleElement, feed.getTitleEx()); eFeed.addContent(titleElement); } List links = feed.getAlternateLinks(); if (links != null) for (int i = 0; i < links.size(); i++) { eFeed.addContent(generateLinkElement((Link) links.get(i))); } links = feed.getOtherLinks(); if (links != null) for (int j = 0; j < links.size(); j++) { eFeed.addContent(generateLinkElement((Link) links.get(j))); } List cats = feed.getCategories(); if (cats != null) for (Iterator iter = cats.iterator(); iter.hasNext();) { eFeed.addContent(generateCategoryElement((Category) iter.next())); } List authors = feed.getAuthors(); if (authors != null && authors.size() > 0) { for (int i = 0; i < authors.size(); i++) { Element authorElement = new Element("author", getFeedNamespace()); fillPersonElement(authorElement, (Person) feed.getAuthors().get(i)); eFeed.addContent(authorElement); } } List contributors = feed.getContributors(); if (contributors != null && contributors.size() > 0) { for (int i = 0; i < contributors.size(); i++) { Element contributorElement = new Element("contributor", getFeedNamespace()); fillPersonElement(contributorElement, (Person) contributors.get(i)); eFeed.addContent(contributorElement); } } if (feed.getSubtitle() != null) { Element subtitleElement = new Element("subtitle", getFeedNamespace()); fillContentElement(subtitleElement, feed.getSubtitle()); eFeed.addContent(subtitleElement); } if (feed.getId() != null) { eFeed.addContent(generateSimpleElement("id", feed.getId())); } if (feed.getGenerator() != null) { eFeed.addContent(generateGeneratorElement(feed.getGenerator())); } if (feed.getRights() != null) { eFeed.addContent(generateSimpleElement("rights", feed.getRights())); } if (feed.getIcon() != null) { eFeed.addContent(generateSimpleElement("icon", feed.getIcon())); } if (feed.getLogo() != null) { eFeed.addContent(generateSimpleElement("logo", feed.getLogo())); } if (feed.getUpdated() != null) { Element updatedElement = new Element("updated", getFeedNamespace()); updatedElement.addContent(DateParser.formatW3CDateTime(feed.getUpdated())); eFeed.addContent(updatedElement); } } protected void populateEntry(Entry entry, Element eEntry) throws FeedException { if (entry.getTitleEx() != null) { Element titleElement = new Element("title", getFeedNamespace()); fillContentElement(titleElement, entry.getTitleEx()); eEntry.addContent(titleElement); } List links = entry.getAlternateLinks(); if (links != null) { for (int i = 0; i < links.size(); i++) { eEntry.addContent(generateLinkElement((Link) links.get(i))); } } links = entry.getOtherLinks(); if (links != null) { for (int i = 0; i < links.size(); i++) { eEntry.addContent(generateLinkElement((Link) links.get(i))); } } List cats = entry.getCategories(); if (cats != null) { for (int i = 0; i < cats.size(); i++) { eEntry.addContent(generateCategoryElement((Category) cats.get(i))); } } List authors = entry.getAuthors(); if (authors != null && authors.size() > 0) { for (int i = 0; i < authors.size(); i++) { Element authorElement = new Element("author", getFeedNamespace()); fillPersonElement(authorElement, (Person) entry.getAuthors().get(i)); eEntry.addContent(authorElement); } } List contributors = entry.getContributors(); if (contributors != null && contributors.size() > 0) { for (int i = 0; i < contributors.size(); i++) { Element contributorElement = new Element("contributor", getFeedNamespace()); fillPersonElement(contributorElement, (Person) contributors.get(i)); eEntry.addContent(contributorElement); } } if (entry.getId() != null) { eEntry.addContent(generateSimpleElement("id", entry.getId())); } if (entry.getUpdated() != null) { Element updatedElement = new Element("updated", getFeedNamespace()); updatedElement.addContent(DateParser.formatW3CDateTime(entry.getUpdated())); eEntry.addContent(updatedElement); } if (entry.getPublished() != null) { Element publishedElement = new Element("published", getFeedNamespace()); publishedElement.addContent(DateParser.formatW3CDateTime(entry.getPublished())); eEntry.addContent(publishedElement); } if (entry.getContents() != null && entry.getContents().size() > 0) { Element contentElement = new Element("content", getFeedNamespace()); Content content = (Content) entry.getContents().get(0); fillContentElement(contentElement, content); eEntry.addContent(contentElement); } if (entry.getSummary() != null) { Element summaryElement = new Element("summary", getFeedNamespace()); fillContentElement(summaryElement, entry.getSummary()); eEntry.addContent(summaryElement); } if (entry.getSource() != null) { Element sourceElement = new Element("source", getFeedNamespace()); populateFeedHeader(entry.getSource(), sourceElement); eEntry.addContent(sourceElement); } } protected void checkFeedHeaderConstraints(Element eFeed) throws FeedException { } protected void checkEntriesConstraints(Element parent) throws FeedException { } protected void checkEntryConstraints(Element eEntry) throws FeedException { } protected Element generateCategoryElement(Category cat) { Element catElement = new Element("category", getFeedNamespace()); if (cat.getTerm() != null) { Attribute termAttribute = new Attribute("term", cat.getTerm()); catElement.setAttribute(termAttribute); } if (cat.getLabel() != null) { Attribute labelAttribute = new Attribute("label", cat.getLabel()); catElement.setAttribute(labelAttribute); } if (cat.getScheme() != null) { Attribute schemeAttribute = new Attribute("scheme", cat.getScheme()); catElement.setAttribute(schemeAttribute); } return catElement; } protected Element generateLinkElement(Link link) { Element linkElement = new Element("link", getFeedNamespace()); if (link.getRel() != null) { Attribute relAttribute = new Attribute("rel", link.getRel()); linkElement.setAttribute(relAttribute); } if (link.getType() != null) { Attribute typeAttribute = new Attribute("type", link.getType()); linkElement.setAttribute(typeAttribute); } if (link.getHref() != null) { Attribute hrefAttribute = new Attribute("href", link.getHref()); linkElement.setAttribute(hrefAttribute); } if (link.getHreflang() != null) { Attribute hreflangAttribute = new Attribute("hreflang", link.getHreflang()); linkElement.setAttribute(hreflangAttribute); } if (link.getTitle() != null) { Attribute title = new Attribute("title", link.getTitle()); linkElement.setAttribute(title); } if (link.getLength() != 0) { Attribute lenght = new Attribute("length", Long.toString(link.getLength())); linkElement.setAttribute(lenght); } return linkElement; } protected void fillPersonElement(Element element, Person person) { if (person.getName() != null) { element.addContent(generateSimpleElement("name", person.getName())); } if (person.getUri() != null) { element.addContent(generateSimpleElement("uri", person.getUri())); } if (person.getEmail() != null) { element.addContent(generateSimpleElement("email", person.getEmail())); } generatePersonModules(person.getModules(), element); } protected Element generateTagLineElement(Content tagline) { Element taglineElement = new Element("subtitle", getFeedNamespace()); if (tagline.getType() != null) { Attribute typeAttribute = new Attribute("type", tagline.getType()); taglineElement.setAttribute(typeAttribute); } if (tagline.getValue() != null) { taglineElement.addContent(tagline.getValue()); } return taglineElement; } protected void fillContentElement(Element contentElement, Content content) throws FeedException { String type = content.getType(); String atomType = type; if (type != null) { // Fix for issue #39 "Atom 1.0 Text Types Not Set Correctly" // we're not sure who set this value, so ensure Atom types are used if ("text/plain".equals(type)) atomType = Content.TEXT; else if ("text/html".equals(type)) atomType = Content.HTML; else if ("application/xhtml+xml".equals(type)) atomType = Content.XHTML; Attribute typeAttribute = new Attribute("type", atomType); contentElement.setAttribute(typeAttribute); } String href = content.getSrc(); if (href != null) { Attribute srcAttribute = new Attribute("src", href); contentElement.setAttribute(srcAttribute); } if (content.getValue() != null) { if (atomType != null && (atomType.equals(Content.XHTML) || (atomType.indexOf("/xml")) != -1 || (atomType.indexOf("+xml")) != -1)) { StringBuffer tmpDocString = new StringBuffer("<tmpdoc>"); tmpDocString.append(content.getValue()); tmpDocString.append("</tmpdoc>"); StringReader tmpDocReader = new StringReader(tmpDocString.toString()); Document tmpDoc; try { SAXBuilder saxBuilder = new SAXBuilder(); tmpDoc = saxBuilder.build(tmpDocReader); } catch (Exception ex) { throw new FeedException("Invalid XML", ex); } List children = tmpDoc.getRootElement().removeContent(); contentElement.addContent(children); } else { // must be type html, text or some other non-XML format // JDOM will escape property for XML contentElement.addContent(content.getValue()); } } } protected Element generateGeneratorElement(Generator generator) { Element generatorElement = new Element("generator", getFeedNamespace()); if (generator.getUrl() != null) { Attribute urlAttribute = new Attribute("uri", generator.getUrl()); generatorElement.setAttribute(urlAttribute); } if (generator.getVersion() != null) { Attribute versionAttribute = new Attribute("version", generator.getVersion()); generatorElement.setAttribute(versionAttribute); } if (generator.getValue() != null) { generatorElement.addContent(generator.getValue()); } return generatorElement; } protected Element generateSimpleElement(String name, String value) { Element element = new Element(name, getFeedNamespace()); element.addContent(value); return element; } /** * Utility method to serialize an entry to writer. */ public static void serializeEntry(Entry entry, Writer writer) throws IllegalArgumentException, FeedException, IOException { // Build a feed containing only the entry List entries = new ArrayList(); entries.add(entry); Feed feed1 = new Feed(); feed1.setFeedType("atom_1.0"); feed1.setEntries(entries); // Get Rome to output feed as a JDOM document WireFeedOutput wireFeedOutput = new WireFeedOutput(); Document feedDoc = wireFeedOutput.outputJDom(feed1); // Grab entry element from feed and get JDOM to serialize it Element entryElement = (Element) feedDoc.getRootElement().getChildren().get(0); XMLOutputter outputter = new XMLOutputter(); outputter.output(entryElement, writer); } }