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.util.ArrayList; import java.util.Iterator; import java.util.List; import org.jdom2.Document; import org.jdom2.Element; import org.jdom2.Namespace; import org.jdom2.output.XMLOutputter; 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.WireFeedInput; import com.sun.syndication.io.WireFeedOutput; import java.io.IOException; import java.io.Reader; import java.net.MalformedURLException; import java.util.regex.Pattern; import org.jdom2.Attribute; import org.jdom2.JDOMException; import org.jdom2.Parent; import org.jdom2.input.SAXBuilder; /** * Parser for Atom 1.0 * @author Dave Johnson */ public class Atom10Parser extends BaseWireFeedParser { private static final String ATOM_10_URI = "http://www.w3.org/2005/Atom"; private static final Namespace ATOM_10_NS = Namespace.getNamespace(ATOM_10_URI); private static boolean resolveURIs = false; public static void setResolveURIs(boolean resolveURIs) { Atom10Parser.resolveURIs = resolveURIs; } public static boolean getResolveURIs() { return resolveURIs; } public Atom10Parser() { this("atom_1.0"); } protected Atom10Parser(String type) { super(type, ATOM_10_NS); } protected Namespace getAtomNamespace() { return ATOM_10_NS; } public boolean isMyType(Document document) { Element rssRoot = document.getRootElement(); Namespace defaultNS = rssRoot.getNamespace(); return (defaultNS != null) && defaultNS.equals(getAtomNamespace()); } public WireFeed parse(Document document, boolean validate) throws IllegalArgumentException, FeedException { if (validate) { validateFeed(document); } Element rssRoot = document.getRootElement(); return parseFeed(rssRoot); } protected void validateFeed(Document document) throws FeedException { // TBD // here we have to validate the Feed against a schema or whatever // not sure how to do it // one posibility would be to produce an ouput and attempt to parse it again // with validation turned on. // otherwise will have to check the document elements by hand. } protected WireFeed parseFeed(Element eFeed) throws FeedException { String baseURI = null; try { baseURI = findBaseURI(eFeed); } catch (Exception e) { throw new FeedException("ERROR while finding base URI of feed", e); } Feed feed = parseFeedMetadata(baseURI, eFeed); String xmlBase = eFeed.getAttributeValue("base", Namespace.XML_NAMESPACE); if (xmlBase != null) { feed.setXmlBase(xmlBase); } feed.setModules(parseFeedModules(eFeed)); List eList = eFeed.getChildren("entry", getAtomNamespace()); if (eList.size() > 0) { feed.setEntries(parseEntries(feed, baseURI, eList)); } List foreignMarkup = extractForeignMarkup(eFeed, feed, getAtomNamespace()); if (foreignMarkup.size() > 0) { feed.setForeignMarkup(foreignMarkup); } return feed; } private Feed parseFeedMetadata(String baseURI, Element eFeed) { com.sun.syndication.feed.atom.Feed feed = new com.sun.syndication.feed.atom.Feed(getType()); Element e = eFeed.getChild("title", getAtomNamespace()); if (e != null) { Content c = new Content(); c.setValue(parseTextConstructToString(e)); c.setType(getAttributeValue(e, "type")); feed.setTitleEx(c); } List eList = eFeed.getChildren("link", getAtomNamespace()); feed.setAlternateLinks(parseAlternateLinks(feed, null, baseURI, eList)); feed.setOtherLinks(parseOtherLinks(feed, null, baseURI, eList)); List cList = eFeed.getChildren("category", getAtomNamespace()); feed.setCategories(parseCategories(baseURI, cList)); eList = eFeed.getChildren("author", getAtomNamespace()); if (eList.size() > 0) { feed.setAuthors(parsePersons(baseURI, eList)); } eList = eFeed.getChildren("contributor", getAtomNamespace()); if (eList.size() > 0) { feed.setContributors(parsePersons(baseURI, eList)); } e = eFeed.getChild("subtitle", getAtomNamespace()); if (e != null) { Content subtitle = new Content(); subtitle.setValue(parseTextConstructToString(e)); subtitle.setType(getAttributeValue(e, "type")); feed.setSubtitle(subtitle); } e = eFeed.getChild("id", getAtomNamespace()); if (e != null) { feed.setId(e.getText()); } e = eFeed.getChild("generator", getAtomNamespace()); if (e != null) { Generator gen = new Generator(); gen.setValue(e.getText()); String att = getAttributeValue(e, "uri"); if (att != null) { gen.setUrl(att); } att = getAttributeValue(e, "version"); if (att != null) { gen.setVersion(att); } feed.setGenerator(gen); } e = eFeed.getChild("rights", getAtomNamespace()); if (e != null) { feed.setRights(parseTextConstructToString(e)); } e = eFeed.getChild("icon", getAtomNamespace()); if (e != null) { feed.setIcon(e.getText()); } e = eFeed.getChild("logo", getAtomNamespace()); if (e != null) { feed.setLogo(e.getText()); } e = eFeed.getChild("updated", getAtomNamespace()); if (e != null) { feed.setUpdated(DateParser.parseDate(e.getText())); } return feed; } private Link parseLink(Feed feed, Entry entry, String baseURI, Element eLink) { Link link = new Link(); String att = getAttributeValue(eLink, "rel"); if (att != null) { link.setRel(att); } att = getAttributeValue(eLink, "type"); if (att != null) { link.setType(att); } att = getAttributeValue(eLink, "href"); if (att != null) { link.setHref(att); if (isRelativeURI(att)) { link.setHrefResolved(resolveURI(baseURI, eLink, att)); } } att = getAttributeValue(eLink, "title"); if (att != null) { link.setTitle(att); } att = getAttributeValue(eLink, "hreflang"); if (att != null) { link.setHreflang(att); } att = getAttributeValue(eLink, "length"); if (att != null) { Long val = NumberParser.parseLong(att); if (val != null) { link.setLength(val.longValue()); } } return link; } // List(Elements) -> List(Link) private List parseAlternateLinks(Feed feed, Entry entry, String baseURI, List eLinks) { List links = new ArrayList(); for (int i = 0; i < eLinks.size(); i++) { Element eLink = (Element) eLinks.get(i); Link link = parseLink(feed, entry, baseURI, eLink); if (link.getRel() == null || "".equals(link.getRel().trim()) || "alternate".equals(link.getRel())) { links.add(link); } } return (links.size() > 0) ? links : null; } private List parseOtherLinks(Feed feed, Entry entry, String baseURI, List eLinks) { List links = new ArrayList(); for (int i = 0; i < eLinks.size(); i++) { Element eLink = (Element) eLinks.get(i); Link link = parseLink(feed, entry, baseURI, eLink); if (!"alternate".equals(link.getRel())) { links.add(link); } } return (links.size() > 0) ? links : null; } private Person parsePerson(String baseURI, Element ePerson) { Person person = new Person(); Element e = ePerson.getChild("name", getAtomNamespace()); if (e != null) { person.setName(e.getText()); } e = ePerson.getChild("uri", getAtomNamespace()); if (e != null) { person.setUri(e.getText()); if (isRelativeURI(e.getText())) { person.setUriResolved(resolveURI(baseURI, ePerson, e.getText())); } } e = ePerson.getChild("email", getAtomNamespace()); if (e != null) { person.setEmail(e.getText()); } person.setModules(parsePersonModules(ePerson)); return person; } // List(Elements) -> List(Persons) private List parsePersons(String baseURI, List ePersons) { List persons = new ArrayList(); for (int i = 0; i < ePersons.size(); i++) { persons.add(parsePerson(baseURI, (Element) ePersons.get(i))); } return (persons.size() > 0) ? persons : null; } private Content parseContent(Element e) { String value = parseTextConstructToString(e); String src = getAttributeValue(e, "src"); String type = getAttributeValue(e, "type"); Content content = new Content(); content.setSrc(src); content.setType(type); content.setValue(value); return content; } private String parseTextConstructToString(Element e) { String value = null; String type = getAttributeValue(e, "type"); type = (type != null) ? type : Content.TEXT; if (type.equals(Content.XHTML) || (type.indexOf("/xml")) != -1 || (type.indexOf("+xml")) != -1) { // XHTML content needs special handling XMLOutputter outputter = new XMLOutputter(); List eContent = e.getContent(); Iterator i = eContent.iterator(); while (i.hasNext()) { org.jdom2.Content c = (org.jdom2.Content) i.next(); if (c instanceof Element) { Element eC = (Element) c; if (eC.getNamespace().equals(getAtomNamespace())) { ((Element) c).setNamespace(Namespace.NO_NAMESPACE); } } } value = outputter.outputString(eContent); } else { // Everything else comes in verbatim value = e.getText(); } return value; } // List(Elements) -> List(Entries) protected List parseEntries(Feed feed, String baseURI, List eEntries) { List entries = new ArrayList(); for (int i = 0; i < eEntries.size(); i++) { entries.add(parseEntry(feed, (Element) eEntries.get(i), baseURI)); } return (entries.size() > 0) ? entries : null; } protected Entry parseEntry(Feed feed, Element eEntry, String baseURI) { Entry entry = new Entry(); String xmlBase = eEntry.getAttributeValue("base", Namespace.XML_NAMESPACE); if (xmlBase != null) { entry.setXmlBase(xmlBase); } Element e = eEntry.getChild("title", getAtomNamespace()); if (e != null) { Content c = new Content(); c.setValue(parseTextConstructToString(e)); c.setType(getAttributeValue(e, "type")); entry.setTitleEx(c); } List eList = eEntry.getChildren("link", getAtomNamespace()); entry.setAlternateLinks(parseAlternateLinks(feed, entry, baseURI, eList)); entry.setOtherLinks(parseOtherLinks(feed, entry, baseURI, eList)); eList = eEntry.getChildren("author", getAtomNamespace()); if (eList.size() > 0) { entry.setAuthors(parsePersons(baseURI, eList)); } eList = eEntry.getChildren("contributor", getAtomNamespace()); if (eList.size() > 0) { entry.setContributors(parsePersons(baseURI, eList)); } e = eEntry.getChild("id", getAtomNamespace()); if (e != null) { entry.setId(e.getText()); } e = eEntry.getChild("updated", getAtomNamespace()); if (e != null) { entry.setUpdated(DateParser.parseDate(e.getText())); } e = eEntry.getChild("published", getAtomNamespace()); if (e != null) { entry.setPublished(DateParser.parseDate(e.getText())); } e = eEntry.getChild("summary", getAtomNamespace()); if (e != null) { entry.setSummary(parseContent(e)); } e = eEntry.getChild("content", getAtomNamespace()); if (e != null) { List contents = new ArrayList(); contents.add(parseContent(e)); entry.setContents(contents); } e = eEntry.getChild("rights", getAtomNamespace()); if (e != null) { entry.setRights(e.getText()); } List cList = eEntry.getChildren("category", getAtomNamespace()); entry.setCategories(parseCategories(baseURI, cList)); // TODO: SHOULD handle Atom entry source element e = eEntry.getChild("source", getAtomNamespace()); if (e != null) { entry.setSource(parseFeedMetadata(baseURI, e)); } entry.setModules(parseItemModules(eEntry)); List foreignMarkup = extractForeignMarkup(eEntry, entry, getAtomNamespace()); if (foreignMarkup.size() > 0) { entry.setForeignMarkup(foreignMarkup); } return entry; } private List parseCategories(String baseURI, List eCategories) { List cats = new ArrayList(); for (int i = 0; i < eCategories.size(); i++) { Element eCategory = (Element) eCategories.get(i); cats.add(parseCategory(baseURI, eCategory)); } return (cats.size() > 0) ? cats : null; } private Category parseCategory(String baseURI, Element eCategory) { Category category = new Category(); String att = getAttributeValue(eCategory, "term"); if (att != null) { category.setTerm(att); } att = getAttributeValue(eCategory, "scheme"); if (att != null) { category.setScheme(att); if (isRelativeURI(att)) { category.setSchemeResolved(resolveURI(baseURI, eCategory, att)); } } att = getAttributeValue(eCategory, "label"); if (att != null) { category.setLabel(att); } return category; } // Once following relative URI methods are made public in the ROME // Atom10Parser, then use them instead and delete these. // Fix for issue #34 "valid IRI href attributes are stripped for atom:link" // URI's that didn't start with http were being treated as relative URIs. // So now consider an absolute URI to be any alpha-numeric string followed // by a colon, followed by anything -- specified by this regex: static Pattern absoluteURIPattern = Pattern.compile("^[a-z0-9]*:.*$"); public static boolean isAbsoluteURI(String uri) { return absoluteURIPattern.matcher(uri).find(); } /** Returns true if URI is relative. */ public static boolean isRelativeURI(String uri) { return !isAbsoluteURI(uri); } /** * Resolve URI via base URL and parent element. * Resolve URI based considering xml:base and baseURI. * @param baseURI Base URI used to fetch the XML document * @param parent Parent element from which to consider xml:base * @param url URL to be resolved */ public static String resolveURI(String baseURI, Parent parent, String url) { if (!resolveURIs) { return url; } if (isRelativeURI(url)) { url = (!".".equals(url) && !"./".equals(url)) ? url : ""; if (url.startsWith("/") && baseURI != null) { String base = null; int slashslash = baseURI.indexOf("//"); int nextslash = baseURI.indexOf("/", slashslash + 2); if (nextslash != -1) base = baseURI.substring(0, nextslash); return formURI(base, url); } // Relative URI with parent if (parent != null && parent instanceof Element) { // Do we have an xml:base? String xmlbase = ((Element) parent).getAttributeValue("base", Namespace.XML_NAMESPACE); if (xmlbase != null && xmlbase.trim().length() > 0) { if (isAbsoluteURI(xmlbase)) { // Absolute xml:base, so form URI right now if (url.startsWith("/")) { // Host relative URI int slashslash = xmlbase.indexOf("//"); int nextslash = xmlbase.indexOf("/", slashslash + 2); if (nextslash != -1) xmlbase = xmlbase.substring(0, nextslash); return formURI(xmlbase, url); } if (!xmlbase.endsWith("/")) { // Base URI is filename, strip it off xmlbase = xmlbase.substring(0, xmlbase.lastIndexOf("/")); } return formURI(xmlbase, url); } else { // Relative xml:base, so walk up tree return resolveURI(baseURI, parent.getParent(), stripTrailingSlash(xmlbase) + "/" + stripStartingSlash(url)); } } // No xml:base so walk up tree return resolveURI(baseURI, parent.getParent(), url); // Relative URI with no parent (i.e. top of tree), so form URI right now } else if (parent == null || parent instanceof Document) { return formURI(baseURI, url); } } return url; } /** * Find base URI of feed considering relative URIs. * @param root Root element of feed. */ private String findBaseURI(Element root) throws MalformedURLException { String ret = null; if (findAtomLink(root, "self") != null) { ret = findAtomLink(root, "self"); if (".".equals(ret) || "./".equals(ret)) ret = ""; if (ret.indexOf("/") != -1) ret = ret.substring(0, ret.lastIndexOf("/")); ret = resolveURI(null, root, ret); } return ret; } /** * Return URL string of Atom link element under parent element. * Link with no rel attribute is considered to be rel="alternate" * @param parent Consider only children of this parent element * @param rel Consider only links with this relationship */ private String findAtomLink(Element parent, String rel) { String ret = null; List linksList = parent.getChildren("link", ATOM_10_NS); if (linksList != null) { for (Iterator links = linksList.iterator(); links.hasNext();) { Element link = (Element) links.next(); Attribute relAtt = getAttribute(link, "rel"); Attribute hrefAtt = getAttribute(link, "href"); if ((relAtt == null && "alternate".equals(rel)) || (relAtt != null && relAtt.getValue().equals(rel))) { ret = hrefAtt.getValue(); break; } } } return ret; } /** * Form URI by combining base with append portion and giving * special consideration to append portions that begin with ".." * @param base Base of URI, may end with trailing slash * @param append String to append, may begin with slash or ".." */ private static String formURI(String base, String append) { base = stripTrailingSlash(base); append = stripStartingSlash(append); if (append.startsWith("..")) { String ret = null; String[] parts = append.split("/"); for (int i = 0; i < parts.length; i++) { if ("..".equals(parts[i])) { int last = base.lastIndexOf("/"); if (last != -1) { base = base.substring(0, last); append = append.substring(3, append.length()); } else break; } } } return base + "/" + append; } /** * Strip starting slash from beginning of string. */ private static String stripStartingSlash(String s) { if (s != null && s.startsWith("/")) { s = s.substring(1, s.length()); } return s; } /** * Strip trailing slash from end of string. */ private static String stripTrailingSlash(String s) { if (s != null && s.endsWith("/")) { s = s.substring(0, s.length() - 1); } return s; } /** * Parse entry from reader. */ public static Entry parseEntry(Reader rd, String baseURI) throws JDOMException, IOException, IllegalArgumentException, FeedException { // Parse entry into JDOM tree SAXBuilder builder = new SAXBuilder(); Document entryDoc = builder.build(rd); Element fetchedEntryElement = entryDoc.getRootElement(); fetchedEntryElement.detach(); // Put entry into a JDOM document with 'feed' root so that Rome can handle it Feed feed = new Feed(); feed.setFeedType("atom_1.0"); WireFeedOutput wireFeedOutput = new WireFeedOutput(); Document feedDoc = wireFeedOutput.outputJDom(feed); feedDoc.getRootElement().addContent(fetchedEntryElement); if (baseURI != null) { feedDoc.getRootElement().setAttribute("base", baseURI, Namespace.XML_NAMESPACE); } WireFeedInput input = new WireFeedInput(); Feed parsedFeed = (Feed) input.build(feedDoc); return (Entry) parsedFeed.getEntries().get(0); } }