org.apache.activemq.artemis.core.server.cluster.qourum

Class QuorumManager

java.lang.Object

org.apache.activemq.artemis.core.server.cluster.qourum.QuorumManager

All Implemented Interfaces:

ClusterTopologyListener, ActiveMQComponent

public final class QuorumManager
extends Object
implements ClusterTopologyListener, ActiveMQComponent

A QourumManager can be used to register a Quorum to receive notifications about changes to the cluster. A Quorum can then issue a vote to the remaining nodes in a cluster for a specific outcome

Constructor Summary

Constructors

Constructor and Description
QuorumManager(ExecutorService threadPool, ClusterController clusterController)

Method Summary

Modifier and Type	Method and Description
int	getMaxClusterSize() returns the maximum size this cluster has been.
QuorumVoteHandler	getVoteHandler(SimpleString handler)
boolean	isStarted() are we started
void	nodeDown(long eventUID, String nodeID) notify the Quorum of a topology change.
void	nodeUP(TopologyMember topologyMember, boolean last) called by the ServerLocatorInternal when the topology changes.
void	registerQuorum(Quorum quorum) registers a Quorum so that it can be notified of changes in the cluster.
void	registerQuorumHandler(QuorumVoteHandler quorumVoteHandler) called to register vote handlers on the quorum
void	start() we start by simply creating the server locator and connecting in a separate thread
void	stop() stops the server locator
String	toString()
void	unRegisterQuorum(Quorum quorum) unregisters a Quorum.
void	vote(QuorumVote quorumVote) ask the quorum to vote within a specific quorum.
Vote	vote(SimpleString handler, Vote vote) handle a vote received on the quorum
void	voteComplete(QuorumVoteServerConnect quorumVote) must be called by the quorum when it is happy on an outcome.

Methods inherited from class java.lang.Object

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

Constructor Detail

QuorumManager

public QuorumManager(ExecutorService threadPool,
                     ClusterController clusterController)

Method Detail

start

public void start()
           throws Exception

we start by simply creating the server locator and connecting in a separate thread

Specified by:

start in interface ActiveMQComponent

Throws:

Exception

stop

public void stop()
          throws Exception

stops the server locator

Specified by:

stop in interface ActiveMQComponent

Throws:

Exception

isStarted

public boolean isStarted()

are we started

Specified by:

isStarted in interface ActiveMQComponent

Returns:

registerQuorum

public void registerQuorum(Quorum quorum)

registers a Quorum so that it can be notified of changes in the cluster.

Parameters:

quorum -

unRegisterQuorum

public void unRegisterQuorum(Quorum quorum)

unregisters a Quorum.

Parameters:

quorum -

nodeUP

public void nodeUP(TopologyMember topologyMember,
                   boolean last)

called by the ServerLocatorInternal when the topology changes. we update the maxClusterSize if needed and inform the Quorum's.

Specified by:

nodeUP in interface ClusterTopologyListener

Parameters:

topologyMember - the topolgy changed

last - if the whole cluster topology is being transmitted (after adding the listener to the cluster connection) this parameter will be true for the last topology

nodeDown

public void nodeDown(long eventUID,
                     String nodeID)

notify the Quorum of a topology change.

Specified by:

nodeDown in interface ClusterTopologyListener

Parameters:

eventUID -

nodeID - the id of the node leaving the cluster

getMaxClusterSize

public int getMaxClusterSize()

returns the maximum size this cluster has been.

Returns:

max size

vote

public void vote(QuorumVote quorumVote)

ask the quorum to vote within a specific quorum.

Parameters:

quorumVote - the vote to acquire

vote

public Vote vote(SimpleString handler,
                 Vote vote)

handle a vote received on the quorum

Parameters:

handler - the name of the handler to use for the vote

vote - the vote

Returns:

the updated vote

voteComplete

public void voteComplete(QuorumVoteServerConnect quorumVote)

must be called by the quorum when it is happy on an outcome. only one vote can take place at anyone time for a specific quorum

Parameters:

quorumVote - the vote

registerQuorumHandler

public void registerQuorumHandler(QuorumVoteHandler quorumVoteHandler)

called to register vote handlers on the quorum

Parameters:

quorumVoteHandler - the vote handler

toString

public String toString()

Overrides:

toString in class Object

getVoteHandler

public QuorumVoteHandler getVoteHandler(SimpleString handler)