org.apache.hadoop.hive.metastore.leader

Class StaticLeaderElection

java.lang.Object

org.apache.hadoop.hive.metastore.leader.StaticLeaderElection

All Implemented Interfaces:

Closeable, AutoCloseable, LeaderElection<String>

public class StaticLeaderElection
extends Object
implements LeaderElection<String>

URL based leader election via metastore.housekeeping.leader.hostname. If the value is empty, means no election happening and all instances are leaders, otherwise the instance matching the configured hostname will be selected as a leader.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.hive.metastore.leader.LeaderElection

LeaderElection.LeadershipStateListener

Constructor Summary

Constructors

Constructor and Description
StaticLeaderElection()

Method Summary

Modifier and Type	Method and Description
void	addStateListener(LeaderElection.LeadershipStateListener listener) Register listeners to get notified when leadership changes.
void	close()
String	getName() Get the name of this leader candidate
boolean	isLeader() Getting the result of election.
void	setName(String name) Set the name of this leader candidate
void	tryBeLeader(org.apache.hadoop.conf.Configuration conf, String hostName) Place where election happens

Methods inherited from class java.lang.Object

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

Constructor Detail

StaticLeaderElection

public StaticLeaderElection()

Method Detail

tryBeLeader

public void tryBeLeader(org.apache.hadoop.conf.Configuration conf,
                        String hostName)
                 throws LeaderException

Description copied from interface: LeaderElection

Place where election happens

Specified by:

tryBeLeader in interface LeaderElection<String>

Parameters:

conf - configuration

hostName - a global mutex for leader election. It can be a path in Zookeeper, or a table that going to be locked.

Throws:

LeaderException

isLeader

public boolean isLeader()

Description copied from interface: LeaderElection

Getting the result of election.

Specified by:

isLeader in interface LeaderElection<String>

Returns:

true if wins the election, false otherwise.

addStateListener

public void addStateListener(LeaderElection.LeadershipStateListener listener)

Description copied from interface: LeaderElection

Register listeners to get notified when leadership changes.

Specified by:

addStateListener in interface LeaderElection<String>

Parameters:

listener - The listener to be added

setName

public void setName(String name)

Description copied from interface: LeaderElection

Set the name of this leader candidate

Specified by:

setName in interface LeaderElection<String>

Parameters:

name - the name

getName

public String getName()

Description copied from interface: LeaderElection

Get the name of this leader candidate

Specified by:

getName in interface LeaderElection<String>

close

public void close()

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable