Package org.apache.pekko.cluster.sharding

Class ShardCoordinator

java.lang.Object
org.apache.pekko.cluster.sharding.ShardCoordinator
All Implemented Interfaces:
Actor, Timers
Direct Known Subclasses:
PersistentShardCoordinator
public abstract class ShardCoordinator extends Object implements Actor, Timers
Singleton coordinator that decides where to allocate shards.

See Also:

  • Constructor Details

  • Method Details

    • leastShardAllocationStrategy

      public static ShardCoordinator.ShardAllocationStrategy leastShardAllocationStrategy(int absoluteLimit, double relativeLimit)
      Java API: ShardAllocationStrategy that allocates new shards to the ShardRegion (node) with least number of previously allocated shards.

      When a node is added to the cluster the shards on the existing nodes will be rebalanced to the new node. The LeastShardAllocationStrategy picks shards for rebalancing from the ShardRegions with most number of previously allocated shards. They will then be allocated to the ShardRegion with least number of previously allocated shards, i.e. new members in the cluster. The amount of shards to rebalance in each round can be limited to make it progress slower since rebalancing too many shards at the same time could result in additional load on the system. For example, causing many Event Sourced entities to be started at the same time.

      It will not rebalance when there is already an ongoing rebalance in progress.

      Parameters:
      absoluteLimit - the maximum number of shards that will be rebalanced in one rebalance round
      relativeLimit - fraction (< 1.0) of total number of (known) shards that will be rebalanced in one rebalance round

    • context

      public ActorContext context()
      Description copied from interface: Actor
      Scala API: Stores the context for this actor, including self, and sender. It is implicit to support operations such as forward.

      WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!

      pekko.actor.ActorContext is the Scala API. getContext returns a pekko.actor.AbstractActor.ActorContext, which is the Java API of the actor context.

      Specified by:
      context in interface Actor

    • self

      public final ActorRef self()
      Description copied from interface: Actor
      The 'self' field holds the ActorRef for this actor.

      Can be used to send messages to itself: 
       self ! message
      Specified by:
      self in interface Actor

    • org$apache$pekko$actor$Actor$_setter_$context_$eq

      protected void org$apache$pekko$actor$Actor$_setter_$context_$eq(ActorContext x$1)
      Description copied from interface: Actor
      Scala API: Stores the context for this actor, including self, and sender. It is implicit to support operations such as forward.

      WARNING: Only valid within the Actor itself, so do not close over it and publish it to other threads!

      pekko.actor.ActorContext is the Scala API. getContext returns a pekko.actor.AbstractActor.ActorContext, which is the Java API of the actor context.

      Specified by:
      org$apache$pekko$actor$Actor$_setter_$context_$eq in interface Actor

    • org$apache$pekko$actor$Actor$_setter_$self_$eq

      protected final void org$apache$pekko$actor$Actor$_setter_$self_$eq(ActorRef x$1)
      Description copied from interface: Actor
      The 'self' field holds the ActorRef for this actor.

      Can be used to send messages to itself: 
       self ! message
      Specified by:
      org$apache$pekko$actor$Actor$_setter_$self_$eq in interface Actor

    • log

      public MarkerLoggingAdapter log()

    • cluster

      public Cluster cluster()

    • removalMargin

      public scala.concurrent.duration.FiniteDuration removalMargin()

    • minMembers

      public int minMembers()

    • allRegionsRegistered

      public boolean allRegionsRegistered()

    • allRegionsRegistered_$eq

      public void allRegionsRegistered_$eq(boolean x$1)

    • state

      public org.apache.pekko.cluster.sharding.ShardCoordinator.Internal.State state()

    • state_$eq

      public void state_$eq(org.apache.pekko.cluster.sharding.ShardCoordinator.Internal.State x$1)

    • preparingForShutdown

      public boolean preparingForShutdown()

    • preparingForShutdown_$eq

      public void preparingForShutdown_$eq(boolean x$1)

    • rebalanceInProgress

      public scala.collection.immutable.Map<String,scala.collection.immutable.Set<ActorRef>> rebalanceInProgress()

    • rebalanceInProgress_$eq

      public void rebalanceInProgress_$eq(scala.collection.immutable.Map<String,scala.collection.immutable.Set<ActorRef>> x$1)

    • rebalanceWorkers

      public scala.collection.immutable.Set<ActorRef> rebalanceWorkers()

    • rebalanceWorkers_$eq

      public void rebalanceWorkers_$eq(scala.collection.immutable.Set<ActorRef> x$1)

    • unAckedHostShards

      public scala.collection.immutable.Map<String,Cancellable> unAckedHostShards()

    • unAckedHostShards_$eq

      public void unAckedHostShards_$eq(scala.collection.immutable.Map<String,Cancellable> x$1)

    • gracefulShutdownInProgress

      public scala.collection.immutable.Set<ActorRef> gracefulShutdownInProgress()

    • gracefulShutdownInProgress_$eq

      public void gracefulShutdownInProgress_$eq(scala.collection.immutable.Set<ActorRef> x$1)

    • waitingForLocalRegionToTerminate

      public boolean waitingForLocalRegionToTerminate()

    • waitingForLocalRegionToTerminate_$eq

      public void waitingForLocalRegionToTerminate_$eq(boolean x$1)

    • aliveRegions

      public scala.collection.immutable.Set<ActorRef> aliveRegions()

    • aliveRegions_$eq

      public void aliveRegions_$eq(scala.collection.immutable.Set<ActorRef> x$1)

    • regionTerminationInProgress

      public scala.collection.immutable.Set<ActorRef> regionTerminationInProgress()

    • regionTerminationInProgress_$eq

      public void regionTerminationInProgress_$eq(scala.collection.immutable.Set<ActorRef> x$1)

    • typeName

      protected abstract String typeName()

    • preStart

      public void preStart()
      Description copied from interface: Actor
      User overridable callback.

      Is called when an Actor is started. Actors are automatically started asynchronously when created. Empty default implementation.
      Specified by:
      preStart in interface Actor

    • postStop

      public void postStop()
      Description copied from interface: Actor
      User overridable callback.

      Is called asynchronously after 'actor.stop()' is invoked. Empty default implementation.
      Specified by:
      postStop in interface Actor

    • isMember

      public boolean isMember(ActorRef region)

    • active

      public scala.PartialFunction<Object,scala.runtime.BoxedUnit> active()

    • handleGetShardHome

      public boolean handleGetShardHome(String shard)
      Returns:
      true if the message could be handled without state update, i.e. the shard location was known or the request was deferred or ignored

    • receiveTerminated

      public scala.PartialFunction<Object,scala.runtime.BoxedUnit> receiveTerminated()

    • update

      public abstract <E extends org.apache.pekko.cluster.sharding.ShardCoordinator.Internal.DomainEvent> void update(E evt, scala.Function1<E,scala.runtime.BoxedUnit> f)

    • watchStateActors

      public void watchStateActors()

    • stateInitialized

      public void stateInitialized()

    • hasAllRegionsRegistered

      public boolean hasAllRegionsRegistered()

    • regionTerminated

      public void regionTerminated(ActorRef ref)

    • regionProxyTerminated

      public void regionProxyTerminated(ActorRef ref)

    • shuttingDown

      public scala.PartialFunction<Object,scala.runtime.BoxedUnit> shuttingDown()

    • sendHostShardMsg

      public void sendHostShardMsg(String shard, ActorRef region)

    • allocateShardHomesForRememberEntities

      public void allocateShardHomesForRememberEntities()

    • continueGetShardHome

      public void continueGetShardHome(String shard, ActorRef region, ActorRef getShardHomeSender)

    • unstashOneGetShardHomeRequest

      protected abstract void unstashOneGetShardHomeRequest()

    • continueRebalance

      public void continueRebalance(scala.collection.immutable.Set<String> shards)

    • shutdownShards

      public void shutdownShards(ActorRef shuttingDownRegion, scala.collection.immutable.Set<String> shards)