Package org.apache.pekko.routing

Class SmallestMailboxPool

java.lang.Object
org.apache.pekko.routing.SmallestMailboxPool
All Implemented Interfaces:
Serializable, Pool, PoolOverrideUnsetConfig<SmallestMailboxPool>, RouterConfig, scala.Equals, scala.Product
public final class SmallestMailboxPool extends Object implements Pool, PoolOverrideUnsetConfig<SmallestMailboxPool>, scala.Product, Serializable
A router pool that tries to send to the non-suspended routee with fewest messages in mailbox. The selection is done in this order:
  • pick any idle routee (not processing message) with empty mailbox
  • pick any routee with empty mailbox
  • pick routee with fewest pending messages in mailbox
  • pick any remote routee, remote actors are consider lowest priority, since their mailbox size is unknown

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(org.apache.pekko.actor.SupervisorStrategy). If no strategy is provided, routers default to a strategy of &ldquo;always escalate&rdquo;. 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.

param: nrOfInstances initial number of routees in the pool

param: resizer optional resizer that dynamically adjust the pool size

param: supervisorStrategy strategy for supervising the routees, see 'Supervision Setup'

param: routerDispatcher dispatcher to use for the router head actor, which handles supervision, death watch and router management messages

See Also:

  • Constructor Details

    • SmallestMailboxPool

      public SmallestMailboxPool(int nrOfInstances, scala.Option<Resizer> resizer, SupervisorStrategy supervisorStrategy, String routerDispatcher, boolean usePoolDispatcher)

    • SmallestMailboxPool

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

    • SmallestMailboxPool

      public SmallestMailboxPool(int nr)
      Java API
      Parameters:
      nr - initial number of routees in the pool

  • Method Details

    • $lessinit$greater$default$2

      public static scala.Option<Resizer> $lessinit$greater$default$2()

    • $lessinit$greater$default$3

      public static SupervisorStrategy $lessinit$greater$default$3()

    • $lessinit$greater$default$4

      public static String $lessinit$greater$default$4()

    • $lessinit$greater$default$5

      public static boolean $lessinit$greater$default$5()

    • apply

      public static SmallestMailboxPool apply(int nrOfInstances, scala.Option<Resizer> resizer, SupervisorStrategy supervisorStrategy, String routerDispatcher, boolean usePoolDispatcher)

    • apply$default$2

      public static scala.Option<Resizer> apply$default$2()

    • apply$default$3

      public static SupervisorStrategy apply$default$3()

    • apply$default$4

      public static String apply$default$4()

    • apply$default$5

      public static boolean apply$default$5()

    • unapply

      public static scala.Option<scala.Tuple5<Object,scala.Option<Resizer>,SupervisorStrategy,String,Object>> unapply(SmallestMailboxPool x$0)

    • nrOfInstances

      public int nrOfInstances()

    • resizer

      public scala.Option<Resizer> resizer()
      Description copied from interface: Pool
      Pool with dynamically resizable number of routees return the pekko.routing.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

    • 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 String routerDispatcher()
      Description copied from interface: RouterConfig
      Dispatcher ID to use for running the &ldquo;head&rdquo; 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

    • nrOfInstances

      public int nrOfInstances(ActorSystem sys)
      Description copied from interface: Pool
      Initial number of routee instances
      Specified by:
      nrOfInstances in interface Pool

    • withSupervisorStrategy

      public SmallestMailboxPool withSupervisorStrategy(SupervisorStrategy strategy)
      Setting the supervisor strategy to be used for the &ldquo;head&rdquo; Router actor.
      Specified by:
      withSupervisorStrategy in interface PoolOverrideUnsetConfig<SmallestMailboxPool>

    • withResizer

      public SmallestMailboxPool withResizer(Resizer resizer)
      Setting the resizer to be used.
      Specified by:
      withResizer in interface PoolOverrideUnsetConfig<SmallestMailboxPool>

    • withDispatcher

      public SmallestMailboxPool withDispatcher(String dispatcherId)
      Setting the dispatcher to be used for the router head actor, which handles supervision, death watch and router management messages.

    • 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.
      Specified by:
      withFallback in interface RouterConfig

    • copy

      public SmallestMailboxPool copy(int nrOfInstances, scala.Option<Resizer> resizer, SupervisorStrategy supervisorStrategy, String routerDispatcher, boolean usePoolDispatcher)

    • copy$default$1

      public int copy$default$1()

    • copy$default$2

      public scala.Option<Resizer> copy$default$2()

    • copy$default$3

      public SupervisorStrategy copy$default$3()

    • copy$default$4

      public String copy$default$4()

    • copy$default$5

      public boolean copy$default$5()

    • productPrefix

      public String productPrefix()
      Specified by:
      productPrefix in interface scala.Product

    • productArity

      public int productArity()
      Specified by:
      productArity in interface scala.Product

    • productElement

      public Object productElement(int x$1)
      Specified by:
      productElement in interface scala.Product

    • productIterator

      public scala.collection.Iterator<Object> productIterator()
      Specified by:
      productIterator in interface scala.Product

    • canEqual

      public boolean canEqual(Object x$1)
      Specified by:
      canEqual in interface scala.Equals

    • productElementName

      public String productElementName(int x$1)
      Specified by:
      productElementName in interface scala.Product

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • equals

      public boolean equals(Object x$1)
      Specified by:
      equals in interface scala.Equals
      Overrides:
      equals in class Object