Package org.apache.pekko.cluster.sharding.typed.javadsl

Class Entity<M,E>

java.lang.Object

org.apache.pekko.cluster.sharding.typed.javadsl.Entity<M,E>

public final class Entity<M,E>
extends Object

Defines how the entity should be created. Used in ClusterSharding.init(org.apache.pekko.cluster.sharding.typed.javadsl.Entity<M, E>).

Constructor Summary

Constructors

Constructor	Description
Entity()

Method Summary

Modifier and Type	Method	Description
Optional<ShardCoordinator.ShardAllocationStrategy>	allocationStrategy()
Function<EntityContext<M>,Behavior<M>>	createBehavior()
Optional<String>	dataCenter()
Props	entityProps()
Optional<ShardingMessageExtractor<E,M>>	messageExtractor()
static <M> Entity<M,ShardingEnvelope<M>>	of(EntityTypeKey<M> typeKey, Function<EntityContext<M>,Behavior<M>> createBehavior)	Defines how the entity should be created.
Optional<String>	role()
Optional<ClusterShardingSettings>	settings()
Optional<M>	stopMessage()
EntityTypeKey<M>	typeKey()
Entity<M,E>	withAllocationStrategy(ShardCoordinator.ShardAllocationStrategy newAllocationStrategy)	Allocation strategy which decides on which nodes to allocate new shards, ClusterSharding.defaultShardAllocationStrategy(org.apache.pekko.cluster.sharding.typed.ClusterShardingSettings) is used if this is not specified.
Entity<M,E>	withDataCenter(String newDataCenter)	The data center of the cluster nodes where the cluster sharding is running.
Entity<M,E>	withEntityProps(Props newEntityProps)	pekko.actor.typed.Props of the entity actors, such as dispatcher settings.
<Envelope> Entity<M,Envelope>	withMessageExtractor(ShardingMessageExtractor<Envelope,M> newExtractor)	If a messageExtractor is not specified the messages are sent to the entities by wrapping them in ShardingEnvelope with the entityId of the recipient actor.
Entity<M,E>	withRole(String role)	Run the Entity actors on nodes with the given role.
Entity<M,E>	withSettings(ClusterShardingSettings newSettings)	Additional settings, typically loaded from configuration.
Entity<M,E>	withStopMessage(M newStopMessage)	Message sent to an entity to tell it to stop, e.g.

Methods inherited from class java.lang.Object

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

Constructor Details

Entity

public Entity()

Method Details

of

public static <M> Entity<M,ShardingEnvelope<M>> of(EntityTypeKey<M> typeKey,
 Function<EntityContext<M>,Behavior<M>> createBehavior)

Defines how the entity should be created. Used in ClusterSharding.init(org.apache.pekko.cluster.sharding.typed.javadsl.Entity<M, E>). More optional settings can be defined using the with methods of the returned Entity.

Parameters:

typeKey - A key that uniquely identifies the type of entity in this cluster

createBehavior - Create the behavior for an entity given a EntityContext (includes entityId)

createBehavior

public Function<EntityContext<M>,Behavior<M>> createBehavior()

typeKey

public EntityTypeKey<M> typeKey()

stopMessage

public Optional<M> stopMessage()

entityProps

public Props entityProps()

settings

public Optional<ClusterShardingSettings> settings()

messageExtractor

public Optional<ShardingMessageExtractor<E,M>> messageExtractor()

allocationStrategy

public Optional<ShardCoordinator.ShardAllocationStrategy> allocationStrategy()

role

public Optional<String> role()

dataCenter

public Optional<String> dataCenter()

withEntityProps

public Entity<M,E> withEntityProps(Props newEntityProps)

pekko.actor.typed.Props of the entity actors, such as dispatcher settings.

withSettings

public Entity<M,E> withSettings(ClusterShardingSettings newSettings)

Additional settings, typically loaded from configuration.

withStopMessage

public Entity<M,E> withStopMessage(M newStopMessage)

Message sent to an entity to tell it to stop, e.g. when rebalanced or passivated. If this is not defined it will be stopped automatically. It can be useful to define a custom stop message if the entity needs to perform some asynchronous cleanup or interactions before stopping.

withMessageExtractor

public <Envelope> Entity<M,Envelope> withMessageExtractor(ShardingMessageExtractor<Envelope,M> newExtractor)

If a messageExtractor is not specified the messages are sent to the entities by wrapping them in ShardingEnvelope with the entityId of the recipient actor. That envelope is used by the HashCodeMessageExtractor for extracting entityId and shardId. The number of shards is then defined by numberOfShards in ClusterShardingSettings, which by default is configured with pekko.cluster.sharding.number-of-shards.

withRole

public Entity<M,E> withRole(String role)

Run the Entity actors on nodes with the given role.

withDataCenter

public Entity<M,E> withDataCenter(String newDataCenter)

The data center of the cluster nodes where the cluster sharding is running. If the dataCenter is not specified then the same data center as current node. If the given dataCenter does not match the data center of the current node the ShardRegion will be started in proxy mode.

withAllocationStrategy

public Entity<M,E> withAllocationStrategy(ShardCoordinator.ShardAllocationStrategy newAllocationStrategy)

Allocation strategy which decides on which nodes to allocate new shards, ClusterSharding.defaultShardAllocationStrategy(org.apache.pekko.cluster.sharding.typed.ClusterShardingSettings) is used if this is not specified.