org.apache.ode.bpel.engine.migration.MigrationHandler Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.ode.bpel.engine.migration;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.Callable;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.ode.bpel.engine.BpelProcess;
import org.apache.ode.bpel.engine.Contexts;
/**
* Checks database schema versions and migrates when necessary.
*/
public class MigrationHandler {
private static final Log __log = LogFactory.getLog(MigrationHandler.class);
public static final int CURRENT_SCHEMA_VERSION = 6;
private Contexts _contexts;
private List migrationLinks = new ArrayList() {{
add(new MigrationLink(1, 2, new Migration[] { new CorrelatorsMigration(),
new CorrelationKeyMigration() } ));
add(new MigrationLink(2, 3, new Migration[] { new CorrelationKeySetMigration() } ));
add(new MigrationLink(4, 3, new Migration[] { new CorrelationKeySetMigration() } ));
add(new MigrationLink(3, 5, new Migration[] { new CorrelationKeySetDataMigration() } ));
add(new MigrationLink(5, 6, new Migration[] { new OutstandingRequestsMigration() } ));
}};
public MigrationHandler(Contexts _contexts) {
this._contexts = _contexts;
}
public boolean migrate(final Set registeredProcesses, int migrationTransactionTimeout) {
if (_contexts.dao.getDataSource() == null) {
__log.debug("No datasource available, stopping migration. Probably running fully in-memory.");
return true;
}
final int version;
try {
version = getDbVersion();
} catch (Throwable e) {
__log.info("The ODE_SCHEMA_VERSION database table doesn't exist. Unless you need to migrate your data" +
"from a past version, this message can be safely ignored.");
return false;
}
if (version == -1) {
__log.info("No schema version available from the database, migrations will be skipped.");
return true;
}
if (version == CURRENT_SCHEMA_VERSION) return true;
try {
boolean success = _contexts.scheduler.execTransaction(new Callable() {
public Boolean call() throws Exception {
ArrayList migrations = new ArrayList();
findMigrations(version, CURRENT_SCHEMA_VERSION, migrations);
if (migrations.size() == 0) {
__log.error("Don't know how to migrate from " + version + " to " + CURRENT_SCHEMA_VERSION + ", aborting");
return false;
} else {
boolean success = true;
for (Migration mig : migrations) {
__log.debug("Running migration " + mig);
success = mig.migrate(registeredProcesses, _contexts.dao.getConnection()) && success;
}
if (!success) _contexts.scheduler.setRollbackOnly();
else setDbVersion(CURRENT_SCHEMA_VERSION);
return success;
}
}
}, migrationTransactionTimeout);
return success;
} catch (Exception e) {
__log.error("An error occured while migrating your database to a newer version of ODE, changes have " +
"been aborted", e);
throw new RuntimeException(e);
}
}
private static class MigrationLink {
int source;
int target;
Migration[] migrations;
public MigrationLink(int source, int target, Migration[] migrations) {
this.source = source;
this.target = target;
this.migrations = migrations;
}
}
/**
* Attempts to find a way from a source to a target and collects the migrations found along. Assumes
* a directed graph with no loops. Guarantees that migrations are collected in the proper start-to-end
* order.
*/
private boolean findMigrations(int source, int target, List ms) {
List l = findLinksTo(target);
for (MigrationLink link : l) {
if (link.source == source || findMigrations(source, link.source, ms)) {
ms.addAll(Arrays.asList(link.migrations));
return true;
}
}
return false;
}
/**
* Finds all the links with a given target.
*/
private List findLinksTo(int target) {
ArrayList mls = new ArrayList();
for (MigrationLink ml : migrationLinks) {
if (ml.target == target) mls.add(ml);
}
return mls;
}
private int getDbVersion() {
int version = -1;
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
conn = _contexts.dao.getDataSource().getConnection();
stmt = conn.prepareStatement("SELECT VERSION FROM ODE_SCHEMA_VERSION");
rs = stmt.executeQuery();
if (rs.next()) version = rs.getInt("VERSION");
} catch (Exception e) {
// Swallow, we'll just abort based on the version number
} finally {
try {
if (rs != null) rs.close();
if (stmt != null) stmt.close();
if (conn != null) conn.close();
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
return version;
}
private void setDbVersion(int version) {
Connection conn = null;
Statement stmt = null;
try {
conn = _contexts.dao.getDataSource().getConnection();
stmt = conn.createStatement();
int res = stmt.executeUpdate("UPDATE ODE_SCHEMA_VERSION SET VERSION = " + version);
// This should never happen but who knows?
if (res == 0) throw new RuntimeException("Couldn't update schema version.");
} catch (Exception e) {
// Swallow, we'll just abort based on the version number
} finally {
try {
if (stmt != null) stmt.close();
if (conn != null) conn.close();
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
}
}