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

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An automated Java patching system
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/* 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 java.util.Map;

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

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
 * 
 * 
 * Alternatively, you can pass the migration system name on the command line as the 
 * first argument.
 * 

 * Below is an example of how this class can be configured in an Ant build.xml file:
 * 
 *   ...
 *  <target name="patch.information" description="Prints out information about patch levels">
 *   <java 
 *       fork="true"
 *       classpathref="patch.classpath" 
 *       failonerror="true" 
 *       classname="com.tacitknowledge.util.migration.jdbc.DistributedMigrationInformation">
 *     <sysproperty key="migration.systemname" value="${application.name}"/>
 *   </java>
 * </target>
 *   ...
 *  
 * 
 * @author  Mike Hardy ([email protected])
 * @see     com.tacitknowledge.util.migration.DistributedMigrationProcess
 * @see     com.tacitknowledge.util.migration.jdbc.DistributedJdbcMigrationLauncherFactory
 */
public class DistributedMigrationInformation
{
    /** Class logger */
    private static Log log = LogFactory.getLog(DistributedMigrationInformation.class);
    
    /**
     * Get the migration level information for the given system name
     *
     * @param arguments the command line arguments, if any (none are used)
     * @exception Exception if anything goes wrong
     */
    public static void main(String[] arguments) throws Exception
    {
        DistributedMigrationInformation info = new DistributedMigrationInformation();
        String migrationName = System.getProperty("migration.systemname");
        String migrationSettings = ConfigurationUtil.getOptionalParam("migration.settings",
                System.getProperties(), arguments, 1);
        
        if (migrationName == null)
        {
            if ((arguments != null) && (arguments.length > 0))
            {
                migrationName = arguments[0].trim();
            }
            else
            {
                throw new IllegalArgumentException("The migration.systemname "
                                                   + "system property is required");
            }
        }
       // info.getMigrationInformation(migrationName);
        info.getMigrationInformation(migrationName, migrationSettings);    
    }
    
    /**
     * Get the migration level information for the given system name
     * 
     * @param systemName the name of the system
     * @return returns the current highest source code patch number
     * @throws Exception if anything goes wrong
     */
    public int getMigrationInformation(String systemName) throws Exception
    {
        return getMigrationInformation(systemName, null);
    }
    
    /**
     * Get the migration level information for the given system name
     * 
     * @param systemName the name of the system
     * @param migrationSettings name of alternate migration.properties file to use
     * @return returns the current highest source code patch number
     * @throws Exception if anything goes wrong
     */
    public int getMigrationInformation(String systemName, String migrationSettings) throws Exception
    {
        // 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
        {
            DistributedJdbcMigrationLauncherFactory factory = 
                new DistributedJdbcMigrationLauncherFactory();
            DistributedJdbcMigrationLauncher launcher = null;

            if (migrationSettings == null)
            {
            	log.info("Using migration.properties (default)");
            	launcher = (DistributedJdbcMigrationLauncher) factory.createMigrationLauncher(systemName);
            }
            else
            {
            	log.info("Using " + migrationSettings);
            	launcher = (DistributedJdbcMigrationLauncher) factory.createMigrationLauncher(systemName, migrationSettings);
            }
            // FIXME test that the migration information is correct
            Map contextMap = launcher.getContexts();
           
            JdbcMigrationContext context = 
                (JdbcMigrationContext) contextMap.keySet().iterator().next();
            
            int currentLevel = launcher.getDatabasePatchLevel(context);
            int nextPatchLevel = launcher.getNextPatchLevel();
            log.info("Current Database patch level is        : " + currentLevel);
            int unappliedPatches = nextPatchLevel - launcher.getDatabasePatchLevel(context) - 1;
            log.info("Current number of unapplied patches is : " + unappliedPatches); 
            log.info("The next patch to author should be     : " + nextPatchLevel);
            return (nextPatchLevel - 1);
        }
        catch (Exception e)
        {
            log.error(e);
            throw e;
        }
    }
}