com.tacitknowledge.util.migration.jdbc.StandaloneMigrationLauncher Maven / Gradle / Ivy

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An automated Java patching system
There is a newer version: 1.4.2
/* Copyright 2004 Tacit Knowledge
 *  
 * Licensed 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 com.tacitknowledge.util.migration.jdbc;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.tacitknowledge.util.migration.MigrationException;
import com.tacitknowledge.util.migration.jdbc.util.MigrationUtil;
import com.tacitknowledge.util.migration.jdbc.util.ConfigurationUtil;

/**
 * Launches the migration process as a standalone application.
 * 
 * This class expects the following Java environment parameters:
 * 

 * migration.systemname - the name of the logical system being migrated
 * migration.settings (optional) - the name of the settings file to use for
 * migration
 * 
 * 
 * Below is an example of how this class can be configured in build.xml:
 * 
 * 
 *   ...
 *  <target name="patch.database" description="Runs the migration system">
 *   <java 
 *       fork="true"
 *       classpathref="patch.classpath" 
 *       failonerror="true" 
 *       classname="com.tacitknowledge.util.migration.jdbc.StandaloneMigrationLauncher">
 *     <sysproperty key="migration.systemname" value="${application.name}"/>
 *   </java>
 * </target>
 *   ...
 * 
 * 
 * @author Mike Hardy ([email protected])
 * @see com.tacitknowledge.util.migration.MigrationProcess
 */
public final class StandaloneMigrationLauncher
{
    /**
     * The force rollback parameter
     */
    private static final String FORCE_ROLLBACK = "-force";

    /**
     * The rollback parameter
     */
    private static final String ROLLBACK = "-rollback";

    /**
     * Class logger
     */
    private static Log log = LogFactory.getLog(StandaloneMigrationLauncher.class);

    /**
     * Private constructor - this object shouldn't be instantiated
     */
    private StandaloneMigrationLauncher()
    {
        // does nothing
    }

    /**
     * Run the migrations for the given system name
     * 
     * @param arguments
     *                the command line arguments, if any
     * @exception Exception
     *                    if anything goes wrong
     */
    public static void main(final String[] arguments) throws Exception
    {

        String migrationSystemName = ConfigurationUtil.getRequiredParam("migration.systemname",
                System.getProperties(), arguments, 0);
        String migrationSettings = ConfigurationUtil.getOptionalParam("migration.settings", System
                .getProperties(), arguments, 1);

        boolean isRollback = false;
        int rollbackLevel = -1;
        boolean forceRollback = false;

        for (int i = 0; i < arguments.length; i++)
        {
            String argument1 = arguments[i];

            if (ROLLBACK.equals(argument1))
            {
                isRollback = true;

                if (i + 2 <= arguments.length)
                {
                    String argument2 = arguments[i + 1];

                    if (argument2 != null)
                    {
                        rollbackLevel = Integer.parseInt(argument2);
                    }
                }

                if (rollbackLevel == -1)
                {
                    // this indicates that the rollback level has not been set
                    throw new MigrationException(
                            "The rollback flag requires a following integer parameter to indicate the rollback level.");
                }
            }

            if (FORCE_ROLLBACK.equals(argument1))
            {
                forceRollback = true;
            }

        }

        // The MigrationLauncher is responsible for handling the interaction
        // between the PatchTable and the underlying MigrationTasks; as each
        // task is executed, the patch level is incremented, etc.
        try
        {
            if (isRollback)
            {
                log
                        .info("Found rollback flag. AutoPatch will attempt to rollback the system to patch level "
                                + rollbackLevel + ".");
                MigrationUtil.doRollbacks(migrationSystemName, migrationSettings, rollbackLevel, forceRollback);
            }
            else
            {
                MigrationUtil.doMigrations(migrationSystemName, migrationSettings);
            }
        }
        catch (Exception e)
        {
            log.error(e);
            throw e;
        }
    }
}