org.graylog2.cluster.leader

Class StaticLeaderElectionService

java.lang.Object

com.google.common.util.concurrent.AbstractIdleService

org.graylog2.cluster.leader.StaticLeaderElectionService

All Implemented Interfaces:

com.google.common.util.concurrent.Service, LeaderElectionService

@Singleton
public class StaticLeaderElectionService
extends com.google.common.util.concurrent.AbstractIdleService
implements LeaderElectionService

Leader election based on the static Configuration.isLeader() setting in the configuration file. After node startup, the leader status is static and will not change.

If the value of Configuration.isLeader() is false, the node will not be a leader, if the value is true, the node will be a leader, unless the node notices upon startup that there is another leader present in the cluster already. In that case the value will be set to false and the node will act as a follower.

Nested Class Summary

Nested classes/interfaces inherited from interface com.google.common.util.concurrent.Service

com.google.common.util.concurrent.Service.Listener, com.google.common.util.concurrent.Service.State

Constructor Summary

Constructors

Constructor and Description
StaticLeaderElectionService(Configuration configuration)

Method Summary

Modifier and Type	Method and Description
boolean	isLeader() Check if the current node is the leader of the cluster.
protected void	shutDown()
protected void	startUp()

Methods inherited from class com.google.common.util.concurrent.AbstractIdleService

addListener, awaitRunning, awaitRunning, awaitRunning, awaitTerminated, awaitTerminated, awaitTerminated, executor, failureCause, isRunning, serviceName, startAsync, state, stopAsync, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

StaticLeaderElectionService

@Inject
public StaticLeaderElectionService(Configuration configuration)

Method Detail

isLeader

public boolean isLeader()

Description copied from interface: LeaderElectionService

Check if the current node is the leader of the cluster.

This method might be called frequently. Implementations should be performant and resource-friendly.

Specified by:

isLeader in interface LeaderElectionService

Returns:

true if the current node is the leader, false if it is not

startUp

protected void startUp()
                throws Exception

Specified by:

startUp in class com.google.common.util.concurrent.AbstractIdleService

Throws:

Exception

shutDown

protected void shutDown()
                 throws Exception

Specified by:

shutDown in class com.google.common.util.concurrent.AbstractIdleService

Throws:

Exception