org.minijax.liquibase

Class LiquibaseHelper

java.lang.Object

org.minijax.liquibase.LiquibaseHelper

public class LiquibaseHelper
extends Object

The LiquibaseHelper class provides helpers to migrate a database and generate new migrations. It is a thin layer that wraps JPA and Liquibase. By default, migrations are added to src/main/resources/changelog.xml. The recommended workflow is to (1) generate a migration, (2) manually inspect the migration, and (3) run the migration if everything looks ok.

Constructor Summary

Constructors

Constructor and Description
LiquibaseHelper(Map<String,String> props) Creates a new helper.

Method Summary

Modifier and Type	Method and Description
void	generateMigrations()
static String	getAuthor(String userName) Returns the migration author name.
String	getChangeLogResourceName()
protected Connection	getConnection(String url, String username, String password) Returns a database connection.
protected liquibase.database.Database	getLiquibaseDatabase(Connection conn)
liquibase.database.Database	getReferenceDatabase() Returns the "reference" database.
File	getResourcesDir()
static boolean	isIgnoredChangeSet(liquibase.changelog.ChangeSet changeSet) Returns true if the change set should be ignored.
void	migrate() Helper utility to perform a Liquibase database migration.
static void	removeObjectQuotingStrategy(File changeLogFile) Removes all "objectQuotingStrategy" attributes.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LiquibaseHelper

public LiquibaseHelper(Map<String,String> props)

Creates a new helper.

Parameters:

props -

Method Detail

getResourcesDir

public File getResourcesDir()

getChangeLogResourceName

public String getChangeLogResourceName()

migrate

public void migrate()
             throws liquibase.exception.LiquibaseException,
                    SQLException

Helper utility to perform a Liquibase database migration.

Throws:

liquibase.exception.LiquibaseException

SQLException

See Also:

Liquibase.update(String)

generateMigrations

public void generateMigrations()
                        throws IOException,
                               liquibase.exception.LiquibaseException,
                               SQLException

Throws:

IOException

liquibase.exception.LiquibaseException

SQLException

getConnection

protected Connection getConnection(String url,
                                   String username,
                                   String password)
                            throws SQLException

Returns a database connection. Override this method in tests to avoid actually connecting to databases.

Parameters:

url -

username -

password -

Returns:

Throws:

SQLException

getLiquibaseDatabase

protected liquibase.database.Database getLiquibaseDatabase(Connection conn)
                                                    throws liquibase.exception.DatabaseException

Throws:

liquibase.exception.DatabaseException

getReferenceDatabase

public liquibase.database.Database getReferenceDatabase()
                                                 throws liquibase.exception.DatabaseException,
                                                        SQLException

Returns the "reference" database. In Liquibase terminology, this is the destination / goal state. We create an empty temporary database, and use JPA to autogenerate the schema.

Returns:

Database connection to the temporary reference database.

Throws:

liquibase.exception.DatabaseException

SQLException

getAuthor

public static String getAuthor(String userName)

Returns the migration author name. Tries to generate it from the system user name.

Parameters:

userName - The current user name.

Returns:

The author name.

isIgnoredChangeSet

public static boolean isIgnoredChangeSet(liquibase.changelog.ChangeSet changeSet)

Returns true if the change set should be ignored. Most tables are managed by JPA. When we create the temporary "goal" database, JPA creates all of the tables for a normal happy path diff. If using JGroups, there is an extra table created called "JGROUPSPING" which tracks all of the members of the JGroups cluster. Because this table is not managed by JPA, it is absent from the "goal" database. Therefore liquibase always tries to drop the table. We need to ignore that.

Parameters:

changeSet - The candidate change set.

Returns:

True if the change set should be ignored.

removeObjectQuotingStrategy

public static void removeObjectQuotingStrategy(File changeLogFile)
                                        throws IOException

Removes all "objectQuotingStrategy" attributes.

Parameters:

changeLogFile - The changelog file.

Throws:

IOException