io.atomix.core.election

Interface LeaderElector<T>

All Superinterfaces:

DistributedPrimitive, SyncPrimitive

public interface LeaderElector<T>
extends SyncPrimitive

LeaderElector provides the same functionality as AsyncLeaderElector with the only difference that all its methods block until the corresponding operation completes.

Field Summary

Fields inherited from interface io.atomix.primitive.DistributedPrimitive

DEFAULT_OPERATION_TIMEOUT_MILLIS

Method Summary

Modifier and Type	Method and Description
void	addListener(LeadershipEventListener<T> listener) Registers a listener to be notified of Leadership changes for all topics.
void	addListener(String topic, LeadershipEventListener<T> listener) Registers a listener to be notified of Leadership changes for all topics.
boolean	anoint(String topic, T identifier) Attempts to promote a node to leadership displacing the current leader.
AsyncLeaderElector<T>	async() Returns the underlying asynchronous primitive.
void	evict(T identifier) Attempts to evict a node from all leadership elections it is registered for.
Leadership<T>	getLeadership(String topic) Returns the Leadership for the specified topic.
Map<String,Leadership<T>>	getLeaderships() Returns the current Leaderships for all topics.
boolean	promote(String topic, T identifier) Attempts to promote a node to top of candidate list.
void	removeListener(LeadershipEventListener<T> listener) Unregisters a previously registered change notification listener.
void	removeListener(String topic, LeadershipEventListener<T> listener) Unregisters a previously registered change notification listener.
Leadership<T>	run(String topic, T identifier) Attempts to become leader for a topic.
void	withdraw(String topic, T identifier) Withdraws from leadership race for a topic.

Methods inherited from interface io.atomix.primitive.SyncPrimitive

close, delete

Methods inherited from interface io.atomix.primitive.DistributedPrimitive

addStateChangeListener, name, protocol, removeStateChangeListener, type

Method Detail

run

Leadership<T> run(String topic,
                  T identifier)

Attempts to become leader for a topic.

Parameters:

topic - leadership topic

identifier - instance identifier of the candidate

Returns:

current Leadership state of the topic

withdraw

void withdraw(String topic,
              T identifier)

Withdraws from leadership race for a topic.

Parameters:

topic - leadership topic

identifier - instance identifier of the candidate to withdraw

anoint

boolean anoint(String topic,
               T identifier)

Attempts to promote a node to leadership displacing the current leader.

Parameters:

topic - leadership topic

identifier - instance identifier of the node to anoint

Returns:

true if leadership transfer was successfully executed; false if it failed. This operation can return false if the node to be made new leader is not registered to run for election for the topic.

promote

boolean promote(String topic,
                T identifier)

Attempts to promote a node to top of candidate list.

Parameters:

topic - leadership topic

identifier - instance identifier of the node to promote

Returns:

true if node is now the top candidate. This operation can fail (i.e. return false) if the node is not registered to run for election for the topic.

evict

void evict(T identifier)

Attempts to evict a node from all leadership elections it is registered for.

If the node the current leader for a topic, this call will force the next candidate (if one exists) to be promoted to leadership.

Parameters:

identifier - instance identifier

getLeadership

Leadership<T> getLeadership(String topic)

Returns the Leadership for the specified topic.

Parameters:

topic - leadership topic

Returns:

current Leadership state of the topic

getLeaderships

Map<String,Leadership<T>> getLeaderships()

Returns the current Leaderships for all topics.

Returns:

topic name to Leadership mapping

addListener

void addListener(LeadershipEventListener<T> listener)

Registers a listener to be notified of Leadership changes for all topics.

Parameters:

listener - listener to notify

removeListener

void removeListener(LeadershipEventListener<T> listener)

Unregisters a previously registered change notification listener.

If the specified listener was not previously registered, this operation will be a noop.

Parameters:

listener - listener to remove

addListener

void addListener(String topic,
                 LeadershipEventListener<T> listener)

Registers a listener to be notified of Leadership changes for all topics.

Parameters:

topic - leadership topic

listener - listener to notify

removeListener

void removeListener(String topic,
                    LeadershipEventListener<T> listener)

Unregisters a previously registered change notification listener.

If the specified listener was not previously registered, this operation will be a noop.

Parameters:

topic - leadership topic

listener - listener to remove

async

AsyncLeaderElector<T> async()

Description copied from interface: SyncPrimitive

Returns the underlying asynchronous primitive.

Specified by:

async in interface SyncPrimitive

Returns:

the underlying asynchronous primitive