Java tutorial
/* * See the NOTICE file distributed with this work for additional * information regarding copyright ownership. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software 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 software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ package com.xpn.xwiki.store.migration; import java.util.Arrays; import java.util.Collection; import java.util.HashSet; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Set; import java.util.SortedMap; import java.util.TreeMap; import org.apache.commons.collections.set.ListOrderedSet; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.xpn.xwiki.XWikiContext; import com.xpn.xwiki.XWikiException; /** * Template for {@link XWikiMigrationManagerInterface}. * * @version $Id: 609901ddb9ac67d74b478308356358b239d8f533 $ */ public abstract class AbstractXWikiMigrationManager implements XWikiMigrationManagerInterface { /** logger. */ private static final Logger LOGGER = LoggerFactory.getLogger(AbstractXWikiMigrationManager.class); /** * Internal class used to find out the migrators that are being forced in the XWiki configuration file. */ protected class XWikiMigration { public boolean isForced; public XWikiMigratorInterface migrator; public XWikiMigration(XWikiMigratorInterface migrator, boolean isForced) { this.migrator = migrator; this.isForced = isForced; } } /** * The database version when the migration process starts (before any migrator is applied). This is useful for * mirgator which need to run only when the database is in a certain version. */ private XWikiDBVersion startupVersion; /** * Unified constructor for all subclasses. * * @param context - used everywhere */ public AbstractXWikiMigrationManager(XWikiContext context) throws XWikiException { this.startupVersion = getDBVersion(context); } /** * read data version from xwiki.cfg. * * @param context used for read config * @return data version if set, or null. */ protected XWikiDBVersion getDBVersionFromConfig(XWikiContext context) { String ver = context.getWiki().getConfig().getProperty("xwiki.store.migration.version"); return ver == null ? null : new XWikiDBVersion(Integer.parseInt(ver)); } @Override public XWikiDBVersion getDBVersion(XWikiContext context) throws XWikiException { XWikiDBVersion result = getDBVersionFromConfig(context); return result == null ? new XWikiDBVersion(0) : result; } /** * @param version to set * @param context used everywhere * @throws XWikiException if any error */ protected abstract void setDBVersion(XWikiDBVersion version, XWikiContext context) throws XWikiException; @Override public void startMigrations(XWikiContext context) throws XWikiException { if (context.getWiki().isVirtualMode()) { // Save context values so that we can restore them as they were before the migration. String currentDatabase = context.getDatabase(); String currentOriginalDatabase = context.getOriginalDatabase(); try { for (Iterator it = getDatabasesToMigrate(context).iterator(); it.hasNext();) { String database = (String) it.next(); LOGGER.info("Starting migration for database [{}]...", database); // Set up the context so that it points to the virtual wiki corresponding to the // database. context.setDatabase(database); context.setOriginalDatabase(database); try { // Force the schema update since it's not been executed yet for sub wikis // databases. // TODO: In the future intead of doing this, move all the database schema // update + migrations into XWiki's init (see http://jira.xwiki.org/jira/browse/XWIKI-2075). context.getWiki().getHibernateStore().updateSchema(context, false); // Run the migrations on the current database startMigrationsForDatabase(context); } catch (XWikiException e) { LOGGER.info("Failed to migrate database [" + database + "]...", e); } } } finally { context.setDatabase(currentDatabase); context.setOriginalDatabase(currentOriginalDatabase); } } else { // Just migrate the main wiki try { startMigrationsForDatabase(context); } catch (XWikiException ex) { LOGGER.info("Failed to migrate main database...", ex); } } } /** * Returns the names of the databases that should be migrated. This is controlled through the * "xwiki.store.migration.databases" configuration property in xwiki.cfg. A value of "all" will add all databases. * Note that the main database is automatically added even if not specified. * * @param context The {@link com.xpn.xwiki.XWikiContext} object, needed for accessing the main wiki. * @return The names of all databases to migrate. * @throws XWikiException if the list of wikis cannot be obtained. */ private Set getDatabasesToMigrate(XWikiContext context) throws XWikiException { Set databasesToMigrate = new ListOrderedSet(); // Always migrate the main database. We also want this to be the first database migrated so // it has to be the // first returned in the list. databasesToMigrate.add(context.getMainXWiki()); // Add the databases listed by the user (if any). If there's a single database named and if // it's "all" or "ALL" // then automatically add all the registered databases. if (context.getWiki().isVirtualMode()) { String[] databases = context.getWiki().getConfig().getPropertyAsList("xwiki.store.migration.databases"); if ((databases.length == 1) && databases[0].equalsIgnoreCase("all")) { databasesToMigrate.addAll(context.getWiki().getVirtualWikisDatabaseNames(context)); } else { for (int i = 0; i < databases.length; i++) { databasesToMigrate.add(databases[i]); } } } return databasesToMigrate; } /** * It is assumed that before calling this method the XWiki context has been set with the database to migrate. * * @param context The {@link com.xpn.xwiki.XWikiContext} object, needed for accessing the storage module. * @throws XWikiException if there is an error updating the database. */ private void startMigrationsForDatabase(XWikiContext context) throws XWikiException { try { Collection neededMigrations = getNeededMigrations(context); startMigrations(neededMigrations, context); } catch (Exception e) { throw new XWikiException(XWikiException.MODULE_XWIKI_STORE, XWikiException.ERROR_XWIKI_STORE_MIGRATION, "Migration failed", e); } } /** * @return collection of {@link XWikiMigratorInterface} in ascending order, which need be executed. * @param context used everywhere * @throws Exception if any error */ protected Collection getNeededMigrations(XWikiContext context) throws Exception { XWikiDBVersion curversion = getDBVersion(context); SortedMap neededMigrations = new TreeMap(); Map forcedMigrations = getForcedMigrations(context); if (!forcedMigrations.isEmpty()) { neededMigrations.putAll(forcedMigrations); } else { Set ignoredMigrations = new HashSet(Arrays .asList(context.getWiki().getConfig().getPropertyAsList("xwiki.store.migration.ignored"))); List allMigrations = getAllMigrations(context); for (Iterator it = allMigrations.iterator(); it.hasNext();) { XWikiMigratorInterface migrator = (XWikiMigratorInterface) it.next(); if (ignoredMigrations.contains(migrator.getClass().getName()) || ignoredMigrations.contains(migrator.getVersion().toString())) { continue; } if (migrator.getVersion().compareTo(curversion) >= 0) { XWikiMigration migration = new XWikiMigration(migrator, false); neededMigrations.put(migrator.getVersion(), migration); } } } Collection neededMigrationsAsCollection = neededMigrations.values(); if (LOGGER.isInfoEnabled()) { if (!neededMigrations.isEmpty()) { LOGGER.info("Current storage version = [" + curversion.toString() + "]"); LOGGER.info("List of migrations that will be executed:"); for (Iterator it = neededMigrationsAsCollection.iterator(); it.hasNext();) { XWikiMigration migration = (XWikiMigration) it.next(); if (migration.isForced || migration.migrator.shouldExecute(this.startupVersion)) { LOGGER.info(" " + migration.migrator.getName() + " - " + migration.migrator.getDescription() + (migration.isForced ? " (forced)" : "")); } } } else { LOGGER.info( "No storage migration required since current version is [" + curversion.toString() + "]"); } } return neededMigrationsAsCollection; } protected Map getForcedMigrations(XWikiContext context) throws Exception { SortedMap forcedMigrations = new TreeMap(); String[] forcedMigrationsArray = context.getWiki().getConfig() .getPropertyAsList("xwiki.store.migration.force"); for (int i = 0; i < forcedMigrationsArray.length; i++) { XWikiMigratorInterface migrator = (XWikiMigratorInterface) Class.forName(forcedMigrationsArray[i]) .newInstance(); XWikiMigration migration = new XWikiMigration(migrator, true); forcedMigrations.put(migrator.getVersion(), migration); } return forcedMigrations; } /** * @param migrations - run this migrations in order of collection * @param context - used everywhere * @throws XWikiException if any error */ protected void startMigrations(Collection migrations, XWikiContext context) throws Exception { XWikiDBVersion curversion = getDBVersion(context); for (Iterator it = migrations.iterator(); it.hasNext();) { XWikiMigration migration = (XWikiMigration) it.next(); if (migration.isForced || migration.migrator.shouldExecute(this.startupVersion)) { if (LOGGER.isInfoEnabled()) { LOGGER.info("Running migration [" + migration.migrator.getName() + "] with version [" + migration.migrator.getVersion() + "]"); } migration.migrator.migrate(this, context); } else { if (LOGGER.isInfoEnabled()) { LOGGER.info("Skipping unneeded migration [" + migration.migrator.getName() + "] with version [" + migration.migrator.getVersion() + "]"); } } if (migration.migrator.getVersion().compareTo(curversion) > 0) { setDBVersion(migration.migrator.getVersion().increment(), context); if (LOGGER.isInfoEnabled()) { LOGGER.info("New storage version is now [" + getDBVersion(context) + "]"); } } } } /** * @param context used everywhere * @return List of all {@link XWikiMigratorInterface} for this manager * @throws XWikiException if any error */ protected abstract List getAllMigrations(XWikiContext context) throws XWikiException; }