V5_0_2014_11_04__Enable_XMLWorkflow_Migration.java

/**
 * The contents of this file are subject to the license and copyright
 * detailed in the LICENSE and NOTICE files at the root of the source
 * tree and available online at
 *
 * http://www.dspace.org/license/
 */
package org.dspace.storage.rdbms.xmlworkflow;

import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;
import org.dspace.core.Constants;
import org.dspace.storage.rdbms.DatabaseUtils;
import org.dspace.workflow.factory.WorkflowServiceFactory;
import org.dspace.xmlworkflow.service.XmlWorkflowService;
import org.flywaydb.core.api.migration.MigrationChecksumProvider;
import org.flywaydb.core.api.migration.jdbc.JdbcMigration;
import org.flywaydb.core.internal.util.scanner.classpath.ClassPathResource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This class automatically migrates your DSpace Database to use the
 * XML-based Configurable Workflow system whenever it is enabled.
 * (i.e. workflow.framework=xmlworkflow in workflow.cfg)
 * <P>
 * Because XML-based Configurable Workflow existed prior to our migration, this
 * class first checks for the existence of the "cwf_workflowitem" table before
 * running any migrations.
 * <P>
 * This class represents a Flyway DB Java Migration
 * http://flywaydb.org/documentation/migration/java.html
 * <P>
 * It can upgrade a 5.0 version of DSpace to use the XMLWorkflow.
 * 
 * @author Tim Donohue
 */
public class V5_0_2014_11_04__Enable_XMLWorkflow_Migration
    implements JdbcMigration, MigrationChecksumProvider
{
    /** logging category */
    private static final Logger log = LoggerFactory.getLogger(V5_0_2014_11_04__Enable_XMLWorkflow_Migration.class);
    
    // Size of migration script run
    Integer migration_file_size = -1;
    
    /**
     * Actually migrate the existing database
     * @param connection 
     *     SQL Connection object
     * @throws IOException
     *     A general class of exceptions produced by failed or interrupted I/O operations.
     * @throws SQLException
     *     An exception that provides information on a database access error or other errors.
     */
    @Override
    public void migrate(Connection connection)
            throws IOException, SQLException
    {
        // Make sure XML Workflow is enabled, shouldn't even be needed since this class is only loaded if the service is enabled.
        if (WorkflowServiceFactory.getInstance().getWorkflowService() instanceof XmlWorkflowService
                // If your database was upgraded to DSpace 6 prior to enabling XML Workflow, we MUST skip this 5.x migration, as it is incompatible
                // with a 6.x database. In that scenario the corresponding 6.x XML Workflow migration will create necessary tables.
                && DatabaseUtils.getCurrentFlywayDSpaceState(connection) < 6)
        {
            // Now, check if the XMLWorkflow table (cwf_workflowitem) already exists in this database
            // If XMLWorkflow Table does NOT exist in this database, then lets do the migration!
            // If XMLWorkflow Table ALREADY exists, then this migration is a noop, we assume you manually ran the sql scripts
            if (!DatabaseUtils.tableExists(connection, "cwf_workflowitem"))
            {
                String dbtype = connection.getMetaData().getDatabaseProductName();
                String dbFileLocation = null;
                if(dbtype.toLowerCase().contains("postgres"))
                {
                    dbFileLocation = "postgres";
                }else
                if(dbtype.toLowerCase().contains("oracle")){
                    dbFileLocation = "oracle";
                }


                // Determine path of this migration class (as the SQL scripts 
                // we will run are based on this path under /src/main/resources)
                String packagePath = V5_0_2014_11_04__Enable_XMLWorkflow_Migration.class.getPackage().getName().replace(".", "/");

                // Get the contents of our DB Schema migration script, based on path & DB type
                // (e.g. /src/main/resources/[path-to-this-class]/postgres/xml_workflow_migration.sql)
                String dbMigrateSQL = new ClassPathResource(packagePath + "/" +
                                                        dbFileLocation +
                                                        "/xml_workflow_migration.sql", getClass().getClassLoader()).loadAsString(Constants.DEFAULT_ENCODING);

                // Actually execute the Database schema migration SQL
                // This will create the necessary tables for the XMLWorkflow feature
                DatabaseUtils.executeSql(connection, dbMigrateSQL);

                // Get the contents of our data migration script, based on path & DB type
                // (e.g. /src/main/resources/[path-to-this-class]/postgres/data_workflow_migration.sql)
                String dataMigrateSQL = new ClassPathResource(packagePath + "/" +
                                                          dbFileLocation +
                                                          "/data_workflow_migration.sql", getClass().getClassLoader()).loadAsString(Constants.DEFAULT_ENCODING);

                // Actually execute the Data migration SQL
                // This will migrate all existing traditional workflows to the new XMLWorkflow system & tables
                DatabaseUtils.executeSql(connection, dataMigrateSQL);

                // Assuming both succeeded, save the size of the scripts for getChecksum() below
                migration_file_size = dbMigrateSQL.length() + dataMigrateSQL.length();
            }
        }
    }
    
    /**
     * Return the checksum to be associated with this Migration
     * in the Flyway database table (schema_version).
     * @return checksum as an Integer
     */
    @Override
    public Integer getChecksum()
    {
        return migration_file_size;
    }
}