org.neo4j.kernel.ha.cluster

Class HighAvailabilityMemberStateMachine

java.lang.Object

org.neo4j.kernel.lifecycle.LifecycleAdapter

org.neo4j.kernel.ha.cluster.HighAvailabilityMemberStateMachine

All Implemented Interfaces:

HighAvailability, org.neo4j.kernel.lifecycle.Lifecycle

public class HighAvailabilityMemberStateMachine
extends org.neo4j.kernel.lifecycle.LifecycleAdapter
implements HighAvailability

State machine that listens for global cluster events, and coordinates the internal transitions between HighAvailabilityMemberState. Internal services that wants to know what is going on should register HighAvailabilityMemberListener implementations which will receive callbacks on state changes.

HA in Neo4j is built on top of the clustering functionality. So, this state machine essentially reacts to cluster events, and implements the rules for how HA roles should change, for example, the cluster coordinator should become the HA master.

Nested Class Summary

Nested classes/interfaces inherited from interface org.neo4j.kernel.lifecycle.Lifecycle

org.neo4j.kernel.lifecycle.Lifecycle.Delegate

Field Summary

Fields

Modifier and Type	Field and Description
static org.neo4j.kernel.AvailabilityGuard.AvailabilityRequirement	AVAILABILITY_REQUIREMENT

Constructor Summary

Constructors

Constructor and Description
HighAvailabilityMemberStateMachine(HighAvailabilityMemberContext context, org.neo4j.kernel.AvailabilityGuard availabilityGuard, ObservedClusterMembers members, org.neo4j.cluster.member.ClusterMemberEvents events, org.neo4j.cluster.protocol.election.Election election, org.neo4j.logging.LogProvider logProvider)

Method Summary

Modifier and Type	Method and Description
void	addHighAvailabilityMemberListener(HighAvailabilityMemberListener toAdd)
HighAvailabilityMemberState	getCurrentState()
void	init()
boolean	isMaster()
void	removeHighAvailabilityMemberListener(HighAvailabilityMemberListener toRemove)
void	stop()

Methods inherited from class org.neo4j.kernel.lifecycle.LifecycleAdapter

shutdown, start

Methods inherited from class java.lang.Object

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

Field Detail

AVAILABILITY_REQUIREMENT

public static final org.neo4j.kernel.AvailabilityGuard.AvailabilityRequirement AVAILABILITY_REQUIREMENT

Constructor Detail

HighAvailabilityMemberStateMachine

public HighAvailabilityMemberStateMachine(HighAvailabilityMemberContext context,
                                          org.neo4j.kernel.AvailabilityGuard availabilityGuard,
                                          ObservedClusterMembers members,
                                          org.neo4j.cluster.member.ClusterMemberEvents events,
                                          org.neo4j.cluster.protocol.election.Election election,
                                          org.neo4j.logging.LogProvider logProvider)

Method Detail

init

public void init()
          throws Throwable

Specified by:

init in interface org.neo4j.kernel.lifecycle.Lifecycle

Overrides:

init in class org.neo4j.kernel.lifecycle.LifecycleAdapter

Throws:

Throwable

stop

public void stop()
          throws Throwable

Specified by:

stop in interface org.neo4j.kernel.lifecycle.Lifecycle

Overrides:

stop in class org.neo4j.kernel.lifecycle.LifecycleAdapter

Throws:

Throwable

addHighAvailabilityMemberListener

public void addHighAvailabilityMemberListener(HighAvailabilityMemberListener toAdd)

Specified by:

addHighAvailabilityMemberListener in interface HighAvailability

removeHighAvailabilityMemberListener

public void removeHighAvailabilityMemberListener(HighAvailabilityMemberListener toRemove)

Specified by:

removeHighAvailabilityMemberListener in interface HighAvailability

getCurrentState

public HighAvailabilityMemberState getCurrentState()

isMaster

public boolean isMaster()