Java tutorial
/** * * BibSonomy-Importer - Various importers for bookmarks and publications. * * Copyright (C) 2006 - 2011 Knowledge & Data Engineering Group, * University of Kassel, Germany * http://www.kde.cs.uni-kassel.de/ * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ package org.bibsonomy.importer.bookmark.service; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Collections; import java.util.Date; import java.util.LinkedList; import java.util.List; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.bibsonomy.model.Bookmark; import org.bibsonomy.model.Post; import org.bibsonomy.model.Tag; import org.bibsonomy.model.util.GroupUtils; import org.bibsonomy.model.util.TagUtils; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.NodeList; import org.xml.sax.ErrorHandler; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; public class DeliciousV2Importer { /* * TODO: We do not use the interfaces RelationImporter and RemoteServiceBookmarkImporter since the message signatures are different * can we change that somehow? */ private static final Log log = LogFactory.getLog(DeliciousImporter.class); private static final SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'"); /** * This Method retrieves a list of Posts for a given user. */ public static List<Post<Bookmark>> getPosts(HttpURLConnection connection) throws IOException { final List<Post<Bookmark>> posts = new LinkedList<Post<Bookmark>>(); //open a connection to delicious and retrieve a document connection.connect(); final Document document = getDocument(connection.getInputStream()); connection.disconnect(); /* * TODO: this is copied code from DeliciousImporter */ // traverse document and put everything into Post<Bookmark> Objects final NodeList postList = document.getElementsByTagName("post"); for (int i = 0; i < postList.getLength(); i++) { final Element resource = (Element) postList.item(i); final Post<Bookmark> post = new Post<Bookmark>(); final Bookmark bookmark = new Bookmark(); bookmark.setTitle(resource.getAttribute("description")); bookmark.setUrl(resource.getAttribute("href")); try { post.getTags().addAll(TagUtils.parse(resource.getAttribute("tag"))); } catch (Exception e) { throw new IOException("Could not parse tags. ", e); } //no tags available? -> add one tag to the resource and mark it as "imported" if (post.getTags().isEmpty()) { post.setTags(Collections.singleton(TagUtils.getEmptyTag())); } post.setDescription(resource.getAttribute("extended")); try { post.setDate(df.parse(resource.getAttribute("time"))); } catch (ParseException e) { log.warn("Could not parse date.", e); post.setDate(new Date()); } //set the visibility of the imported resource if (resource.hasAttribute("shared")) { if ("no".equals(resource.getAttribute("shared"))) { post.getGroups().add(GroupUtils.getPrivateGroup()); } else { post.getGroups().add(GroupUtils.getPublicGroup()); } } post.setResource(bookmark); posts.add(post); } return posts; } /** * This method retrieves a list of tags with subTags from Delicious. */ public static List<Tag> getRelations(HttpURLConnection connection) throws IOException { final List<Tag> relations = new LinkedList<Tag>(); //open a connection to delicious and retrieve a document connection.connect(); final Document document = getDocument(connection.getInputStream()); connection.disconnect(); /* * TODO: this is copied code */ final NodeList bundles = document.getElementsByTagName("bundle"); for (int i = 0; i < bundles.getLength(); i++) { final Element resource = (Element) bundles.item(i); try { Tag tag = new Tag(resource.getAttribute("name")); tag.getSubTags().addAll(TagUtils.parse(resource.getAttribute("tags"))); relations.add(tag); } catch (Exception e) { throw new IOException(e); } } return relations; } /** * Method opens a connection and parses the retrieved InputStream with a JAXP parser. * @return The from the parse call returned Document Object * @throws IOException */ private static Document getDocument(final InputStream inputStream) throws IOException { /* * TODO: this is copied code */ // Get a JAXP parser factory object final DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); // Tell the factory what kind of parser we want dbf.setValidating(false); // Use the factory to get a JAXP parser object final DocumentBuilder parser; try { parser = dbf.newDocumentBuilder(); } catch (ParserConfigurationException e) { throw new IOException(e); } // Tell the parser how to handle errors. Note that in the JAXP API, // DOM parsers rely on the SAX API for error handling parser.setErrorHandler(new ErrorHandler() { public void warning(SAXParseException e) { log.warn(e); } public void error(SAXParseException e) { log.error(e); } public void fatalError(SAXParseException e) throws SAXException { log.fatal(e); throw e; // re-throw the error } }); // Finally, use the JAXP parser to parse the file. // This call returns a Document object. final Document document; try { document = parser.parse(inputStream); } catch (SAXException e) { throw new IOException(e); } inputStream.close(); return document; } }