org.apache.cassandra.db.migration
Class Migration

java.lang.Object
  org.apache.cassandra.db.migration.Migration

Direct Known Subclasses:

AddColumnFamily, AddKeyspace, DropColumnFamily, DropKeyspace, RenameColumnFamily, RenameKeyspace, UpdateColumnFamily, UpdateKeyspace

public abstract class Migration
extends java.lang.Object

A migration represents a single metadata mutation (cf dropped, added, etc.). Migrations can be applied locally, or serialized and sent to another machine where it can be applied there. Each migration has a version represented by a TimeUUID that can be used to look up both the Migration itself (see getLocalMigrations) as well as a serialization of the Keyspace definition that was modified. There are three parts to a migration (think of it as a schema update): 1. data is written to the schema cf. 2. the migration is serialized to the migrations cf. 3. updated models are applied to the cassandra instance. Since steps 1, 2 and 3 are not committed atomically, care should be taken to ensure that a node/cluster is reasonably quiescent with regard to the keyspace or columnfamily whose schema is being modified. Each class that extends Migration is required to implement a no arg constructor, which will be used to inflate the object from it's serialized form.

Field Summary

protected boolean	clientMode
static java.nio.ByteBuffer	LAST_MIGRATION_KEY
protected java.util.UUID	lastVersion
protected static org.slf4j.Logger	logger
static java.lang.String	MIGRATIONS_CF
static java.nio.ByteBuffer	MIGRATIONS_KEY
static java.lang.String	NAME_VALIDATOR_REGEX
protected java.util.UUID	newVersion
protected RowMutation	rm
static java.lang.String	SCHEMA_CF

Constructor Summary

protected

Migration() Subclasses must have a matching constructor

Method Summary

protected void	acquireLocks()
void	announce()
void	apply() apply changes
void	beforeApplyModels() override this to perform logic before writing the migration or applying it.
static Migration	deserialize(java.nio.ByteBuffer bytes)
static java.util.UUID	getLastMigrationId()
static java.util.Collection<IColumn>	getLocalMigrations(java.util.UUID start, java.util.UUID end) load serialized migrations.
java.util.UUID	getVersion()
static boolean	isLegalName(java.lang.String s)
protected void	releaseLocks()
java.nio.ByteBuffer	serialize()
abstract void	subdeflate(org.apache.cassandra.db.migration.avro.Migration mi) Deflate this Migration into an Avro object.
abstract void	subinflate(org.apache.cassandra.db.migration.avro.Migration mi) Inflate this Migration from an Avro object: called after the required no-arg constructor.
static java.nio.ByteBuffer	toUTF8Bytes(java.util.UUID version)

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected static final org.slf4j.Logger logger

NAME_VALIDATOR_REGEX

public static final java.lang.String NAME_VALIDATOR_REGEX

See Also:

Constant Field Values

MIGRATIONS_CF

public static final java.lang.String MIGRATIONS_CF

See Also:

Constant Field Values

SCHEMA_CF

public static final java.lang.String SCHEMA_CF

See Also:

Constant Field Values

MIGRATIONS_KEY

public static final java.nio.ByteBuffer MIGRATIONS_KEY

LAST_MIGRATION_KEY

public static final java.nio.ByteBuffer LAST_MIGRATION_KEY

rm

protected RowMutation rm

newVersion

protected java.util.UUID newVersion

lastVersion

protected java.util.UUID lastVersion

clientMode

protected transient boolean clientMode

Constructor Detail

Migration

protected Migration()

Subclasses must have a matching constructor

Method Detail

acquireLocks

protected final void acquireLocks()

releaseLocks

protected final void releaseLocks()

beforeApplyModels

public void beforeApplyModels()

override this to perform logic before writing the migration or applying it. defaults to nothing.

apply

public final void apply()
                 throws java.io.IOException,
                        ConfigurationException

apply changes

Throws:

java.io.IOException

ConfigurationException

announce

public final void announce()

getLastMigrationId

public static java.util.UUID getLastMigrationId()

subdeflate

public abstract void subdeflate(org.apache.cassandra.db.migration.avro.Migration mi)

Deflate this Migration into an Avro object.

subinflate

public abstract void subinflate(org.apache.cassandra.db.migration.avro.Migration mi)

Inflate this Migration from an Avro object: called after the required no-arg constructor.

getVersion

public java.util.UUID getVersion()

serialize

public java.nio.ByteBuffer serialize()
                              throws java.io.IOException

Throws:

java.io.IOException

deserialize

public static Migration deserialize(java.nio.ByteBuffer bytes)
                             throws java.io.IOException

Throws:

java.io.IOException

getLocalMigrations

public static java.util.Collection<IColumn> getLocalMigrations(java.util.UUID start,
                                                               java.util.UUID end)

load serialized migrations.

toUTF8Bytes

public static java.nio.ByteBuffer toUTF8Bytes(java.util.UUID version)

isLegalName

public static boolean isLegalName(java.lang.String s)