akka.routing
Class ConsistentHashingPool

java.lang.Object
  akka.routing.ConsistentHashingPool

All Implemented Interfaces:

Pool, RouterConfig, java.io.Serializable, scala.Equals, scala.Product

public final class ConsistentHashingPool
extends java.lang.Object
implements Pool, scala.Product, scala.Serializable

A router pool that uses consistent hashing to select a routee based on the sent message. The selection is described in ConsistentHashingRoutingLogic.

The configuration parameter trumps the constructor arguments. This means that if you provide nrOfInstances during instantiation they will be ignored if the router is defined in the configuration file for the actor being used.

Supervision Setup

Any routees that are created by a router will be created as the router's children. The router is therefore also the children's supervisor.

The supervision strategy of the router actor can be configured with withSupervisorStrategy(akka.actor.SupervisorStrategy). If no strategy is provided, routers default to a strategy of “always escalate”. This means that errors are passed up to the router's supervisor for handling.

The router's supervisor will treat the error as an error with the router itself. Therefore a directive to stop or restart will cause the router itself to stop or restart. The router, in turn, will cause its children to stop and restart.

See Also:

Serialized Form

Constructor Summary

ConsistentHashingPool(com.typesafe.config.Config config)

ConsistentHashingPool(int nr)
Java API

ConsistentHashingPool(int nrOfInstances, scala.Option<Resizer> resizer, int virtualNodesFactor, scala.PartialFunction<java.lang.Object,java.lang.Object> hashMapping, SupervisorStrategy supervisorStrategy, java.lang.String routerDispatcher, boolean usePoolDispatcher)

Method Summary

Router	createRouter(ActorSystem system) Create the actual router, responsible for routing messages to routees.
scala.PartialFunction<java.lang.Object,java.lang.Object>	hashMapping()
int	nrOfInstances() Initial number of routee instances
RouterConfig	overrideUnsetConfig(RouterConfig other)
scala.Option<Resizer>	resizer() Pool with dynamically resizable number of routees return the Resizer to use.
java.lang.String	routerDispatcher() Dispatcher ID to use for running the “head” actor, which handles supervision, death watch and router management messages
SupervisorStrategy	supervisorStrategy() SupervisorStrategy for the head actor, i.e.
boolean	usePoolDispatcher() Use a dedicated dispatcher for the routees of the pool.
int	virtualNodesFactor()
ConsistentHashingPool	withDispatcher(java.lang.String dispatcherId) Setting the dispatcher to be used for the router head actor, which handles supervision, death watch and router management messages.
RouterConfig	withFallback(RouterConfig other) Uses the resizer and/or the supervisor strategy of the given Routerconfig if this RouterConfig doesn't have one, i.e.
ConsistentHashingPool	withHashMapper(ConsistentHashingRouter.ConsistentHashMapper mapper) Java API: Setting the mapping from message to the data to use for the consistent hash key.
ConsistentHashingPool	withResizer(Resizer resizer) Setting the resizer to be used.
ConsistentHashingPool	withSupervisorStrategy(SupervisorStrategy strategy) Setting the supervisor strategy to be used for the “head” Router actor.
ConsistentHashingPool	withVirtualNodesFactor(int vnodes) Setting the number of virtual nodes per node, used in ConsistentHash

Methods inherited from class java.lang.Object

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

Methods inherited from interface akka.routing.Pool

createRouterActor, defaultSupervisorStrategy, enrichWithPoolDispatcher, newRoutee, props, stopRouterWhenAllRouteesRemoved

Methods inherited from interface akka.routing.RouterConfig

isManagementMessage, routingLogicController, verifyConfig

Methods inherited from interface scala.Product

productArity, productElement, productIterator, productPrefix

Methods inherited from interface scala.Equals

canEqual, equals

Constructor Detail

ConsistentHashingPool

public ConsistentHashingPool(int nrOfInstances,
                             scala.Option<Resizer> resizer,
                             int virtualNodesFactor,
                             scala.PartialFunction<java.lang.Object,java.lang.Object> hashMapping,
                             SupervisorStrategy supervisorStrategy,
                             java.lang.String routerDispatcher,
                             boolean usePoolDispatcher)

ConsistentHashingPool

public ConsistentHashingPool(com.typesafe.config.Config config)

ConsistentHashingPool

public ConsistentHashingPool(int nr)

Java API

Parameters:

nr - initial number of routees in the pool

Method Detail

nrOfInstances

public int nrOfInstances()

Description copied from interface: Pool

Initial number of routee instances

Specified by:

nrOfInstances in interface Pool

resizer

public scala.Option<Resizer> resizer()

Description copied from interface: Pool

Pool with dynamically resizable number of routees return the Resizer to use. The resizer is invoked once when the router is created, before any messages can be sent to it. Resize is also triggered when messages are sent to the routees, and the resizer is invoked asynchronously, i.e. not necessarily before the message has been sent.

Specified by:

resizer in interface Pool

virtualNodesFactor

public int virtualNodesFactor()

hashMapping

public scala.PartialFunction<java.lang.Object,java.lang.Object> hashMapping()

supervisorStrategy

public SupervisorStrategy supervisorStrategy()

Description copied from interface: Pool

SupervisorStrategy for the head actor, i.e. for supervising the routees of the pool.

Specified by:

supervisorStrategy in interface Pool

routerDispatcher

public java.lang.String routerDispatcher()

Description copied from interface: RouterConfig

Dispatcher ID to use for running the “head” actor, which handles supervision, death watch and router management messages

Specified by:

routerDispatcher in interface RouterConfig

usePoolDispatcher

public boolean usePoolDispatcher()

Description copied from interface: Pool

Use a dedicated dispatcher for the routees of the pool. The dispatcher is defined in 'pool-dispatcher' configuration property in the deployment section of the router.

Specified by:

usePoolDispatcher in interface Pool

createRouter

public Router createRouter(ActorSystem system)

Description copied from interface: RouterConfig

Create the actual router, responsible for routing messages to routees.

Specified by:

createRouter in interface RouterConfig

Parameters:

system - the ActorSystem this router belongs to

withSupervisorStrategy

public ConsistentHashingPool withSupervisorStrategy(SupervisorStrategy strategy)

Setting the supervisor strategy to be used for the “head” Router actor.

withResizer

public ConsistentHashingPool withResizer(Resizer resizer)

Setting the resizer to be used.

withDispatcher

public ConsistentHashingPool withDispatcher(java.lang.String dispatcherId)

Setting the dispatcher to be used for the router head actor, which handles supervision, death watch and router management messages.

withVirtualNodesFactor

public ConsistentHashingPool withVirtualNodesFactor(int vnodes)

Setting the number of virtual nodes per node, used in ConsistentHash

withHashMapper

public ConsistentHashingPool withHashMapper(ConsistentHashingRouter.ConsistentHashMapper mapper)

Java API: Setting the mapping from message to the data to use for the consistent hash key.

withFallback

public RouterConfig withFallback(RouterConfig other)

Uses the resizer and/or the supervisor strategy of the given Routerconfig if this RouterConfig doesn't have one, i.e. the resizer defined in code is used if resizer was not defined in config. Uses the the hashMapping defined in code, since that can't be defined in configuration.

Specified by:

withFallback in interface RouterConfig

overrideUnsetConfig

public RouterConfig overrideUnsetConfig(RouterConfig other)