com.hazelcast.spi.impl

Class CountingMigrationAwareService

java.lang.Object

com.hazelcast.spi.impl.CountingMigrationAwareService

All Implemented Interfaces:

MigrationAwareService

public class CountingMigrationAwareService
extends Object
implements MigrationAwareService

A MigrationAwareService that delegates to another MigrationAwareService and keeps track of the number of migrations concerning the partition owner (either as current or new replica index) currently in-flight.

Constructor Summary

Constructors

Constructor and Description
CountingMigrationAwareService(MigrationAwareService migrationAwareService)

Method Summary

Modifier and Type	Method and Description
void	beforeMigration(PartitionMigrationEvent event) Called before migration process starts, on both source and destination members.
void	commitMigration(PartitionMigrationEvent event) Commits the migration process for this service, on both source and destination members.
int	getMigrationStamp() Returns a stamp to denote current migration state which can later be validated using validateMigrationStamp(int).
Operation	prepareReplicationOperation(PartitionReplicationEvent event) Returns an operation to replicate service data and/or state for a specific partition replica on another cluster member.
void	rollbackMigration(PartitionMigrationEvent event) Rollback the migration process for this service, on both source and destination members.
boolean	validateMigrationStamp(int stamp) Returns true if there's no primary replica migrations started and/or completed since issuance of the given stamp.

Methods inherited from class java.lang.Object

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

Constructor Detail

CountingMigrationAwareService

public CountingMigrationAwareService(MigrationAwareService migrationAwareService)

Method Detail

prepareReplicationOperation

public Operation prepareReplicationOperation(PartitionReplicationEvent event)

Description copied from interface: MigrationAwareService

Returns an operation to replicate service data and/or state for a specific partition replica on another cluster member.

This method will be called on source member whenever partitioning system requires to copy/replicate a partition replica. Returned operation will be executed on destination member. If operation fails by throwing exception, migration process will fail and will be rolled back.

Returning null is allowed and means service does not have anything to replicate.

Specified by:

prepareReplicationOperation in interface MigrationAwareService

Parameters:

event - replication

Returns:

replication operation or null if nothing will be replicated

beforeMigration

public void beforeMigration(PartitionMigrationEvent event)

Description copied from interface: MigrationAwareService

Called before migration process starts, on both source and destination members.

Service can take actions required before migration. Migration process will block until this method returns. If this method fails by throwing an exception, migration process for specific partition will fail and will be rolled back.

Specified by:

beforeMigration in interface MigrationAwareService

Parameters:

event - migration event

commitMigration

public void commitMigration(PartitionMigrationEvent event)

Description copied from interface: MigrationAwareService

Commits the migration process for this service, on both source and destination members. This method will be called after all replication operations are executed successfully on destination and master member receives success response from all participants.

Commit is not expected to fail at this point, all exceptions will be suppressed and logged.

Specified by:

commitMigration in interface MigrationAwareService

Parameters:

event - migration event

rollbackMigration

public void rollbackMigration(PartitionMigrationEvent event)

Description copied from interface: MigrationAwareService

Rollback the migration process for this service, on both source and destination members. This method will be called when migration process fails at any moment. Reasons for failure may be an exception thrown on any migration step or failure(s) of any of the migration participants; either master or source or destination.

Rollback is not expected to fail at this point, all exceptions will be suppressed and logged.

Specified by:

rollbackMigration in interface MigrationAwareService

Parameters:

event - migration event

getMigrationStamp

public int getMigrationStamp()

Returns a stamp to denote current migration state which can later be validated using validateMigrationStamp(int).

Returns:

migration stamp

validateMigrationStamp

public boolean validateMigrationStamp(int stamp)

Returns true if there's no primary replica migrations started and/or completed since issuance of the given stamp. Otherwise returns false, if there's an ongoing migration when stamp is issued or a new migration is started (and optionally completed) after stamp is issued.

Parameters:

stamp - a stamp

Returns:

true stamp is valid since issuance of the given stamp, false otherwise