org.apache.storm.zookeeper

Class LeaderElectorImp

java.lang.Object

org.apache.storm.zookeeper.LeaderElectorImp

All Implemented Interfaces:

AutoCloseable, ILeaderElector

public class LeaderElectorImp
extends Object
implements ILeaderElector

Constructor Summary

Constructors

Constructor and Description
LeaderElectorImp(org.apache.storm.shade.org.apache.curator.framework.CuratorFramework zk, String id, LeaderListenerCallbackFactory leaderListenerCallbackFactory)

Method Summary

Modifier and Type	Method and Description
void	addToLeaderLockQueue() queue up for leadership lock.
boolean	awaitLeadership(long timeout, TimeUnit timeUnit) Wait for the caller to gain leadership.
void	close() Method called to allow for cleanup.
List<NimbusInfo>	getAllNimbuses() Get list of current nimbus addresses.
NimbusInfo	getLeader() Get the current leader’s address.
boolean	isLeader() Decide if the caller currently has the leader lock.
void	prepare(Map<String,Object> conf) Method guaranteed to be called as part of initialization of leader elector instance.
void	quitElectionFor(int delayMs) Removes the caller from leadership election, relinquishing leadership if acquired, then requeues for leadership after the specified delay.

Methods inherited from class java.lang.Object

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

Constructor Detail

LeaderElectorImp

public LeaderElectorImp(org.apache.storm.shade.org.apache.curator.framework.CuratorFramework zk,
                        String id,
                        LeaderListenerCallbackFactory leaderListenerCallbackFactory)

Method Detail

prepare

public void prepare(Map<String,Object> conf)

Description copied from interface: ILeaderElector

Method guaranteed to be called as part of initialization of leader elector instance.

Specified by:

prepare in interface ILeaderElector

Parameters:

conf - configuration

addToLeaderLockQueue

public void addToLeaderLockQueue()
                          throws Exception

Description copied from interface: ILeaderElector

queue up for leadership lock. The call returns immediately and the caller must check isLeader() to perform any leadership action. This method can be called multiple times so it needs to be idempotent.

Specified by:

addToLeaderLockQueue in interface ILeaderElector

Throws:

Exception

quitElectionFor

public void quitElectionFor(int delayMs)
                     throws Exception

Description copied from interface: ILeaderElector

Removes the caller from leadership election, relinquishing leadership if acquired, then requeues for leadership after the specified delay.

Specified by:

quitElectionFor in interface ILeaderElector

Parameters:

delayMs - The delay to wait before re-entering the election

Throws:

Exception

isLeader

public boolean isLeader()
                 throws Exception

Description copied from interface: ILeaderElector

Decide if the caller currently has the leader lock.

Specified by:

isLeader in interface ILeaderElector

Returns:

true if the caller currently has the leader lock.

Throws:

Exception

awaitLeadership

public boolean awaitLeadership(long timeout,
                               TimeUnit timeUnit)
                        throws InterruptedException

Description copied from interface: ILeaderElector

Wait for the caller to gain leadership. This should only be used in single-Nimbus clusters, and is only useful to allow testing code to wait for a LocalCluster’s Nimbus to gain leadership before trying to submit topologies.

Specified by:

awaitLeadership in interface ILeaderElector

Returns:

true is leadership was acquired, false otherwise

Throws:

InterruptedException

getLeader

public NimbusInfo getLeader()

Description copied from interface: ILeaderElector

Get the current leader’s address.

Specified by:

getLeader in interface ILeaderElector

Returns:

the current leader’s address, may return null if no one has the lock.

getAllNimbuses

public List<NimbusInfo> getAllNimbuses()
                                throws Exception

Description copied from interface: ILeaderElector

Get list of current nimbus addresses.

Specified by:

getAllNimbuses in interface ILeaderElector

Returns:

list of current nimbus addresses, includes leader.

Throws:

Exception

close

public void close()
           throws Exception

Description copied from interface: ILeaderElector

Method called to allow for cleanup. Relinquishes leadership if owned by the caller.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface ILeaderElector

Throws:

Exception