Java tutorial
/** * Licensed under the GNU LESSER GENERAL PUBLIC LICENSE, version 2.1, dated February 1999. * * This program is free software; you can redistribute it and/or modify * it under the terms of the latest version of the GNU Lesser General * Public License as published by the Free Software Foundation; * * 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program (LICENSE.txt); if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ package org.jamwiki.migrate; import java.io.BufferedWriter; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStreamWriter; import java.io.Writer; import java.sql.Timestamp; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import org.apache.commons.io.IOUtils; import org.jamwiki.DataAccessException; import org.jamwiki.Environment; import org.jamwiki.WikiBase; import org.jamwiki.WikiVersion; import org.jamwiki.model.Namespace; import org.jamwiki.model.RecentChange; import org.jamwiki.model.Topic; import org.jamwiki.model.TopicVersion; import org.jamwiki.model.VirtualWiki; import org.jamwiki.model.WikiUser; import org.jamwiki.parser.WikiLink; import org.jamwiki.utils.Pagination; import org.jamwiki.utils.Utilities; import org.jamwiki.utils.WikiLogger; import org.jamwiki.utils.WikiUtil; import org.jamwiki.utils.XMLUtil; /** * Provide functionality for exporting a JAMWiki topic to Mediawiki XML format. */ public class MediaWikiXmlExporter implements TopicExporter { private static final WikiLogger logger = WikiLogger.getLogger(MediaWikiXmlExporter.class.getName()); private static final SimpleDateFormat MEDIAWIKI_DATE_FORMATTER = new SimpleDateFormat( MediaWikiConstants.ISO_8601_DATE_FORMAT); /** * */ public void exportToFile(File file, String virtualWiki, List<String> topicNames, boolean excludeHistory) throws MigrationException { OutputStreamWriter fileWriter = null; BufferedWriter bufferedWriter = null; boolean success = false; try { fileWriter = new OutputStreamWriter(new FileOutputStream(file), "UTF-8"); bufferedWriter = new BufferedWriter(fileWriter); bufferedWriter.append( "<mediawiki xmlns=\"http://www.mediawiki.org/xml/export-0.7/\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xsi:schemaLocation=\"http://www.mediawiki.org/xml/export-0.7/ http://www.mediawiki.org/xml/export-0.7.xsd\" version=\"0.7\" xml:lang=\"en\">"); this.writeSiteInfo(bufferedWriter, virtualWiki); this.writePages(bufferedWriter, virtualWiki, topicNames, excludeHistory); bufferedWriter.append("\n</mediawiki>"); success = true; } catch (DataAccessException e) { throw new MigrationException(e); } catch (IOException e) { throw new MigrationException(e); } finally { IOUtils.closeQuietly(bufferedWriter); IOUtils.closeQuietly(fileWriter); if (!success) { // make sure partial files are deleted file.delete(); } } } /** * Return the URL of the index page for the wiki. * * @throws DataAccessException Thrown if any error occurs while retrieving data. */ private String retrieveBaseUrl() throws DataAccessException { VirtualWiki virtualWiki = VirtualWiki.defaultVirtualWiki(); String url = Environment.getValue(Environment.PROP_SERVER_URL); WikiLink wikiLink = new WikiLink(WikiUtil.WEBAPP_CONTEXT_PATH, virtualWiki.getName(), virtualWiki.getRootTopicName()); url += wikiLink.toRelativeUrl(); return url; } /** * */ private void writeSiteInfo(Writer writer, String virtualWikiName) throws DataAccessException, IOException { VirtualWiki virtualWiki = WikiBase.getDataHandler().lookupVirtualWiki(virtualWikiName); writer.append("\n<siteinfo>"); String sitename = virtualWiki.getSiteName(); writer.append('\n'); XMLUtil.buildTag(writer, "sitename", sitename, true); String base = this.retrieveBaseUrl(); writer.append('\n'); XMLUtil.buildTag(writer, "base", base, true); String generator = "JAMWiki " + WikiVersion.CURRENT_WIKI_VERSION; writer.append('\n'); XMLUtil.buildTag(writer, "generator", generator, true); /* Cannot have two titles differing only by case of first letter. Default behavior through 1.5, $wgCapitalLinks = true <enumeration value="first-letter" /> Complete title is case-sensitive. Behavior when $wgCapitalLinks = false <enumeration value="case-sensitive" /> Cannot have two titles differing only by case. Not yet implemented as of MediaWiki 1.5 <enumeration value="case-insensitive" /> */ writer.append('\n'); XMLUtil.buildTag(writer, "case", "case-sensitive", true); writer.append("\n<namespaces>"); Map<String, String> attributes = new LinkedHashMap<String, String>(); List<Namespace> namespaces = WikiBase.getDataHandler().lookupNamespaces(); for (Namespace namespace : namespaces) { attributes.put("key", Integer.toString(namespace.getId())); writer.append('\n'); XMLUtil.buildTag(writer, "namespace", namespace.getLabel(virtualWikiName), attributes, true); } writer.append("\n</namespaces>"); writer.append("\n</siteinfo>"); } /** * */ private void writePages(Writer writer, String virtualWiki, List<String> topicNames, boolean excludeHistory) throws DataAccessException, IOException, MigrationException { // note that effort is being made to re-use temporary objects as this // code can generate an OOM "GC overhead limit exceeded" with HUGE (500MB) topics // since the garbage collector ends up being invoked excessively. TopicVersion topicVersion; Topic topic; WikiUser user; // choose 100,000 as an arbitrary default int maxRevisions = (Environment.getIntValue(Environment.PROP_MAX_TOPIC_VERSION_EXPORT) > 0) ? Environment.getIntValue(Environment.PROP_MAX_TOPIC_VERSION_EXPORT) : 100000; int revisionsRetrieved = 0; List<Integer> topicVersionIds; Map<String, String> textAttributes = new LinkedHashMap<String, String>(); textAttributes.put("xml:space", "preserve"); for (String topicName : topicNames) { topicVersionIds = new ArrayList<Integer>(); topic = WikiBase.getDataHandler().lookupTopic(virtualWiki, topicName, false); if (topic == null) { throw new MigrationException( "Failure while exporting: topic " + virtualWiki + ':' + topicName + " does not exist"); } writer.append("\n<page>"); writer.append('\n'); XMLUtil.buildTag(writer, "title", topic.getName(), true); writer.append('\n'); XMLUtil.buildTag(writer, "ns", topic.getNamespace().getId()); writer.append('\n'); XMLUtil.buildTag(writer, "id", topic.getTopicId()); if (excludeHistory || (maxRevisions - revisionsRetrieved) <= 1) { // only include the most recent version topicVersionIds.add(topic.getCurrentVersionId()); } else { // FIXME - changes sorted newest-to-oldest, should be reverse Pagination pagination = new Pagination(maxRevisions - revisionsRetrieved, 0); List<RecentChange> changes = WikiBase.getDataHandler().getTopicHistory(topic, pagination, true); revisionsRetrieved += changes.size(); for (int i = (changes.size() - 1); i >= 0; i--) { topicVersionIds.add(changes.get(i).getTopicVersionId()); } } for (int topicVersionId : topicVersionIds) { topicVersion = WikiBase.getDataHandler().lookupTopicVersion(topicVersionId); writer.append("\n<revision>"); writer.append('\n'); XMLUtil.buildTag(writer, "id", topicVersion.getTopicVersionId()); writer.append('\n'); XMLUtil.buildTag(writer, "timestamp", this.parseJAMWikiTimestamp(topicVersion.getEditDate()), true); writer.append("\n<contributor>"); user = (topicVersion.getAuthorId() != null) ? WikiBase.getDataHandler().lookupWikiUser(topicVersion.getAuthorId()) : null; if (user != null) { writer.append('\n'); XMLUtil.buildTag(writer, "username", user.getUsername(), true); writer.append('\n'); XMLUtil.buildTag(writer, "id", user.getUserId()); } else if (Utilities.isIpAddress(topicVersion.getAuthorDisplay())) { writer.append('\n'); XMLUtil.buildTag(writer, "ip", topicVersion.getAuthorDisplay(), true); } else { writer.append('\n'); XMLUtil.buildTag(writer, "username", topicVersion.getAuthorDisplay(), true); } writer.append("\n</contributor>"); writer.append('\n'); if (topicVersion.getEditType() == TopicVersion.EDIT_MINOR) { XMLUtil.buildTag(writer, "minor", "", true); writer.append('\n'); } XMLUtil.buildTag(writer, "comment", topicVersion.getEditComment(), true); writer.append('\n'); textAttributes.put("bytes", Long.toString(topicVersion.getVersionContent().getBytes().length)); XMLUtil.buildTag(writer, "text", topicVersion.getVersionContent(), textAttributes, true); writer.append("\n</revision>"); // explicitly null out temp variables to improve garbage collection and // avoid OOM "GC overhead limit exceeded" errors on HUGE (500MB) topics topicVersion = null; user = null; } writer.append("\n</page>"); } } /** * */ private String parseJAMWikiTimestamp(Timestamp timestamp) { return MEDIAWIKI_DATE_FORMATTER.format(timestamp); } }