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.io.UnsupportedEncodingException; import java.net.URL; import java.net.URLConnection; 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.codec.binary.Base64; 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.bibsonomy.services.importer.RelationImporter; import org.bibsonomy.services.importer.RemoteServiceBookmarkImporter; 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; /** * * Imports bookmarks and relations from Delicious. To get an instance of this * class, use the {@link DeliciousImporterFactory}. * * This currently works only with the /v1-API. * * @see http://www.delicious.com/help/api writes: * "All /v1 api's require https requests and HTTP-Auth. * To access data from accounts created using a Yahoo! ID, use the same API's as * below, but change the path to /v2, and make HTTP requests using OAuth as * provided by the Yahoo! Developer Network." * * * * @author: rja * @version: $Id: DeliciousImporter.java,v 1.8 2011-01-19 06:38:15 rja Exp $ * $Author: rja $ * */ public class DeliciousImporter implements RemoteServiceBookmarkImporter, RelationImporter { private static final Log log = LogFactory.getLog(DeliciousImporter.class); /** * The URL to contact Delicious. */ private final URL apiURL; private final String userAgent; private String password; private String userName; private static final String HEADER_USER_AGENT = "User-Agent"; private static final String HEADER_AUTHORIZATION = "Authorization"; private static final String HEADER_AUTH_BASIC = "Basic "; private static final String UTF8 = "UTF-8"; private static final SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'"); /** * Constructor which allows to give a specific {@link #apiURL}. * @param apiUrl - the URL to contact delicious * @param userAgent - the userAgent this importer shall use to identify * itself in the corresponding HTTP header */ protected DeliciousImporter(final URL apiUrl, final String userAgent) { this.apiURL = apiUrl; this.userAgent = userAgent; } /** * This Method retrieves a list of Posts for a given user. */ public List<Post<Bookmark>> getPosts() throws IOException { final List<Post<Bookmark>> posts = new LinkedList<Post<Bookmark>>(); //open a connection to delicious and retrieve a document final Document document = getDocument(); // 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 List<Tag> getRelations() throws IOException { final List<Tag> relations = new LinkedList<Tag>(); //open a connection to delicious and retrieve a document final Document document = getDocument(); 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; } @Override public void setCredentials(final String userName, final String password) { this.userName = userName; this.password = password; } /** * 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 Document getDocument() throws IOException { final URLConnection connection = apiURL.openConnection(); connection.setRequestProperty(HEADER_USER_AGENT, userAgent); connection.setRequestProperty(HEADER_AUTHORIZATION, encodeForAuthorization()); final InputStream inputStream = connection.getInputStream(); // 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; } /** * Encode the username and password for BASIC authentication * * @return Basic + Base64 encoded(username + ':' + password) */ protected String encodeForAuthorization() { String retVal = HEADER_AUTH_BASIC; try { retVal += new String(Base64.encodeBase64((this.userName + ":" + this.password).getBytes()), UTF8); } catch (UnsupportedEncodingException e1) { retVal += new String(Base64.encodeBase64((this.userName + ":" + this.password).getBytes())); } return retVal; } }