com.bigdata.quorum

Interface QuorumClient<S extends Remote>

All Superinterfaces:

QuorumListener, ServiceLookup<S>

All Known Subinterfaces:

QuorumMember<S>, QuorumService<S>

All Known Implementing Classes:

AbstractQuorumClient, AbstractQuorumMember, QuorumServiceBase

public interface QuorumClient<S extends Remote>
extends QuorumListener, ServiceLookup<S>

A non-remote interface for a client which monitors the state of a quorum. This interface adds the ability to receive notice of quorum state changes and resolve the Remote interface for the member services of the quorum.

Version:

$Id$

Author:

Bryan Thompson

See Also:

AbstractQuorum.start(QuorumClient)

Method Summary

Methods

Modifier and Type	Method and Description
void	disconnected() The client has become disconnected from the quorum (for zookeeper this is only generated if the session has expired rather than if there is a transient disconnect that can be cured).
S	getLeader(long token) Return the remote interface used to perform HA operations on the quorum leader.
String	getLogicalServiceZPath() The fully qualified identifier of the logical service whose quorum state will be monitored (for zookeeper, this is the logicalServiceZPath).
Quorum<?,?>	getQuorum() The quorum that is being monitored.
S	getService(UUID serviceId) Return the remote interface used to perform HA operations on a member of quorum.
void	start(Quorum<?,?> quorum) Life cycle message sent when the client will begin to receive messages from the Quorum.
void	terminate() Life cycle message send when the client will no longer receive messages from the Quorum.

Methods inherited from interface com.bigdata.quorum.QuorumListener

notify

Method Detail

getLogicalServiceZPath

String getLogicalServiceZPath()

The fully qualified identifier of the logical service whose quorum state will be monitored (for zookeeper, this is the logicalServiceZPath). A highly available service is comprised of multiple physical services which are instances of the same logical service.

Note: The method was renamed from getLogicalServiceId() to getLogicalServiceZPath() to avoid confusion with the zookeeper integration which has both a logicalServiceId (just the last component of the zpath) and a logicalServiceZPath. The Quorum and QuorumClient interfaces only understand a single logical service identifier - this is what corresponds to the for the zookeeper integration.

See Also:

QuorumMember.getServiceId()

start

void start(Quorum<?,?> quorum)

Life cycle message sent when the client will begin to receive messages from the Quorum. At a minimum, the client should save a reference to the Quorum.

Parameters:

quorum - The quorum.

See Also:

AbstractQuorum.start(QuorumClient)

terminate

void terminate()

Life cycle message send when the client will no longer receive messages from the Quorum.

See Also:

AbstractQuorum.terminate()

disconnected

void disconnected()

The client has become disconnected from the quorum (for zookeeper this is only generated if the session has expired rather than if there is a transient disconnect that can be cured). This callback provides a hook to take any local actions that are required when the client can not longer rely on its role in the quorum state (if the client is disconnected from the quorum, then it is no longer part of the quorum, can not be a joined service, quorum member, etc).

getQuorum

Quorum<?,?> getQuorum()

The quorum that is being monitored.

Throws:

QuorumException - if the client is not running with the quorum.

See Also:

start(Quorum)

getService

S getService(UUID serviceId)

Return the remote interface used to perform HA operations on a member of quorum.

Specified by:

getService in interface ServiceLookup<S extends Remote>

Parameters:

serviceId - The UUID associated with the service.

Returns:

The remote interface for that quorum member.

Throws:

IllegalArgumentException - if the argument is null

QuorumException - if there is no Quorum member with that serviceId.

getLeader

S getLeader(long token)

Return the remote interface used to perform HA operations on the quorum leader.

Parameters:

token - The quorum token for which the request was made.

Returns:

The remote interface for the leader.

Throws:

QuorumException - if the quorum token is no longer valid.