org.onosproject.store.primitives

Class DefaultLeaderElector

java.lang.Object

org.onosproject.store.service.Synchronous<AsyncLeaderElector>

org.onosproject.store.primitives.DefaultLeaderElector

All Implemented Interfaces:

DistributedPrimitive, LeaderElector

public class DefaultLeaderElector
extends Synchronous<AsyncLeaderElector>
implements LeaderElector

Default implementation for a LeaderElector backed by a AsyncLeaderElector.

Nested Class Summary

Nested classes/interfaces inherited from interface org.onosproject.store.service.DistributedPrimitive

DistributedPrimitive.Status, DistributedPrimitive.Type

Field Summary

Fields inherited from interface org.onosproject.store.service.DistributedPrimitive

DEFAULT_OPERATION_TIMEOUT_MILLIS, DEFAULT_OPERTATION_TIMEOUT_MILLIS

Constructor Summary

Constructors

Constructor and Description
DefaultLeaderElector(AsyncLeaderElector asyncElector, long operationTimeoutMillis)

Method Summary

Modifier and Type	Method and Description
void	addChangeListener(Consumer<Change<Leadership>> consumer) Registers a listener to be notified of Leadership changes for all topics.
void	addStatusChangeListener(Consumer<DistributedPrimitive.Status> listener) Registers a listener to be called when the primitive's status changes.
boolean	anoint(String topic, NodeId nodeId) Attempts to promote a node to leadership displacing the current leader.
void	evict(NodeId nodeId) Attempts to evict a node from all leadership elections it is registered for.
Leadership	getLeadership(String topic) Returns the Leadership for the specified topic.
Map<String,Leadership>	getLeaderships() Returns the current Leaderships for all topics.
boolean	promote(String topic, NodeId nodeId) Attempts to promote a node to top of candidate list.
void	removeChangeListener(Consumer<Change<Leadership>> consumer) Unregisters a previously registered change notification listener.
void	removeStatusChangeListener(Consumer<DistributedPrimitive.Status> listener) Unregisters a previously registered listener to be called when the primitive's status changes.
Leadership	run(String topic, NodeId nodeId) Attempts to become leader for a topic.
Collection<Consumer<DistributedPrimitive.Status>>	statusChangeListeners() Returns the collection of status change listeners previously registered.
void	withdraw(String topic) Withdraws from leadership race for a topic.

Methods inherited from class org.onosproject.store.service.Synchronous

destroy, name, primitiveType

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.onosproject.store.service.LeaderElector

primitiveType

Methods inherited from interface org.onosproject.store.service.DistributedPrimitive

applicationId, destroy, name

Constructor Detail

DefaultLeaderElector

public DefaultLeaderElector(AsyncLeaderElector asyncElector,
                            long operationTimeoutMillis)

Method Detail

run

public Leadership run(String topic,
                      NodeId nodeId)

Description copied from interface: LeaderElector

Attempts to become leader for a topic.

Specified by:

run in interface LeaderElector

Parameters:

topic - leadership topic

nodeId - instance identifier of the node

Returns:

current Leadership state of the topic

withdraw

public void withdraw(String topic)

Description copied from interface: LeaderElector

Withdraws from leadership race for a topic.

Specified by:

withdraw in interface LeaderElector

Parameters:

topic - leadership topic

anoint

public boolean anoint(String topic,
                      NodeId nodeId)

Description copied from interface: LeaderElector

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

Specified by:

anoint in interface LeaderElector

Parameters:

topic - leadership topic

nodeId - instance identifier of the new leader

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

public boolean promote(String topic,
                       NodeId nodeId)

Description copied from interface: LeaderElector

Attempts to promote a node to top of candidate list.

Specified by:

promote in interface LeaderElector

Parameters:

topic - leadership topic

nodeId - instance identifier of the new top candidate

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

public void evict(NodeId nodeId)

Description copied from interface: LeaderElector

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.

Specified by:

evict in interface LeaderElector

Parameters:

nodeId - node instance identifier

getLeadership

public Leadership getLeadership(String topic)

Description copied from interface: LeaderElector

Returns the Leadership for the specified topic.

Specified by:

getLeadership in interface LeaderElector

Parameters:

topic - leadership topic

Returns:

current Leadership state of the topic

getLeaderships

public Map<String,Leadership> getLeaderships()

Description copied from interface: LeaderElector

Returns the current Leaderships for all topics.

Specified by:

getLeaderships in interface LeaderElector

Returns:

topic name to Leadership mapping

addChangeListener

public void addChangeListener(Consumer<Change<Leadership>> consumer)

Description copied from interface: LeaderElector

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

Specified by:

addChangeListener in interface LeaderElector

Parameters:

consumer - listener to add

removeChangeListener

public void removeChangeListener(Consumer<Change<Leadership>> consumer)

Description copied from interface: LeaderElector

Unregisters a previously registered change notification listener.

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

Specified by:

removeChangeListener in interface LeaderElector

Parameters:

consumer - listener to remove

addStatusChangeListener

public void addStatusChangeListener(Consumer<DistributedPrimitive.Status> listener)

Description copied from interface: DistributedPrimitive

Registers a listener to be called when the primitive's status changes.

Specified by:

addStatusChangeListener in interface DistributedPrimitive

Parameters:

listener - The listener to be called when the status changes.

removeStatusChangeListener

public void removeStatusChangeListener(Consumer<DistributedPrimitive.Status> listener)

Description copied from interface: DistributedPrimitive

Unregisters a previously registered listener to be called when the primitive's status changes.

Specified by:

removeStatusChangeListener in interface DistributedPrimitive

Parameters:

listener - The listener to unregister

statusChangeListeners

public Collection<Consumer<DistributedPrimitive.Status>> statusChangeListeners()

Description copied from interface: DistributedPrimitive

Returns the collection of status change listeners previously registered.

Specified by:

statusChangeListeners in interface DistributedPrimitive

Returns:

collection of status change listeners