Package akka.cluster.sharding

Interface ShardCoordinator.ShardAllocationStrategy

All Superinterfaces:

NoSerializationVerificationNeeded

All Known Implementing Classes:

ShardCoordinator.AbstractShardAllocationStrategy, ShardCoordinator.LeastShardAllocationStrategy

Enclosing class:

ShardCoordinator

public static interface ShardCoordinator.ShardAllocationStrategy
extends NoSerializationVerificationNeeded

Invoked when the location of a new shard is to be decided. param: requester actor reference to the ShardRegion that requested the location of the shard, can be returned if preference should be given to the node where the shard was first accessed param: shardId the id of the shard to allocate param: currentShardAllocations all actor refs to ShardRegion and their current allocated shards, in the order they were allocated

Method Summary

Modifier and Type	Method	Description
scala.concurrent.Future<ActorRef>	allocateShard(ActorRef requester, java.lang.String shardId, scala.collection.immutable.Map<ActorRef,scala.collection.immutable.IndexedSeq<java.lang.String>> currentShardAllocations)
scala.concurrent.Future<scala.collection.immutable.Set<java.lang.String>>	rebalance(scala.collection.immutable.Map<ActorRef,scala.collection.immutable.IndexedSeq<java.lang.String>> currentShardAllocations, scala.collection.immutable.Set<java.lang.String> rebalanceInProgress)	Invoked periodically to decide which shards to rebalance to another location.

Method Detail

allocateShard

scala.concurrent.Future<ActorRef> allocateShard(ActorRef requester,
                                                java.lang.String shardId,
                                                scala.collection.immutable.Map<ActorRef,scala.collection.immutable.IndexedSeq<java.lang.String>> currentShardAllocations)

rebalance

scala.concurrent.Future<scala.collection.immutable.Set<java.lang.String>> rebalance(scala.collection.immutable.Map<ActorRef,scala.collection.immutable.IndexedSeq<java.lang.String>> currentShardAllocations,
                                                                                    scala.collection.immutable.Set<java.lang.String> rebalanceInProgress)

Invoked periodically to decide which shards to rebalance to another location.

Parameters:

currentShardAllocations - all actor refs to ShardRegion and their current allocated shards, in the order they were allocated

rebalanceInProgress - set of shards that are currently being rebalanced, i.e. you should not include these in the returned set

Returns:

a Future of the shards to be migrated, may be empty to skip rebalance in this round