t

akka.cluster.ddata

DeltaReplicatedData

trait DeltaReplicatedData extends ReplicatedData

ReplicatedData with additional support for delta-CRDT replication. delta-CRDT is a way to reduce the need for sending the full state for updates. For example adding element 'c' and 'd' to set {'a', 'b'} would result in sending the delta {'c', 'd'} and merge that with the state on the receiving side, resulting in set {'a', 'b', 'c', 'd'}.

Learn more about this in the paper Delta State Replicated Data Types.

Source
ReplicatedData.scala
Linear Supertypes
ReplicatedData, AnyRef, Any
Known Subclasses
AbstractDeltaReplicatedData, GCounter, GSet, LWWMap, ORMap, ORMultiMap, ORSet, PNCounter, PNCounterMap
Type Hierarchy
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Inherited
  1. DeltaReplicatedData
  2. ReplicatedData
  3. AnyRef
  4. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. Protected

Type Members

  1. abstract type D <: ReplicatedDelta

    The type of the delta.

    The type of the delta. To be specified by subclass. It may be the same type as T or a different type if needed. For example GSet uses the same type and ORSet uses different types.

  2. abstract type T <: ReplicatedData

    The type of the concrete implementation, e.g.

    The type of the concrete implementation, e.g. GSet[A]. To be specified by subclass.

    Definition Classes
    ReplicatedData

Abstract Value Members

  1. abstract def delta: Option[D]

    The accumulated delta of mutator operations since previous #resetDelta.

    The accumulated delta of mutator operations since previous #resetDelta. When the Replicator invokes the modify function of the Update message and the user code is invoking one or more mutator operations the data is collecting the delta of the operations and makes it available for the Replicator with the #delta accessor. The modify function shall still return the full state in the same way as ReplicatedData without support for deltas.

  2. abstract def merge(that: T): T

    Monotonic merge function.

    Monotonic merge function.

    Definition Classes
    ReplicatedData
  3. abstract def mergeDelta(thatDelta: D): T

    When delta is merged into the full state this method is used.

    When delta is merged into the full state this method is used. When the type D of the delta is of the same type as the full state T this method can be implemented by delegating to merge.

  4. abstract def resetDelta: T

    Reset collection of deltas from mutator operations.

    Reset collection of deltas from mutator operations. When the Replicator invokes the modify function of the Update message the delta is always "reset" and when the user code is invoking one or more mutator operations the data is collecting the delta of the operations and makes it available for the Replicator with the #delta accessor. When the Replicator has grabbed the delta it will invoke this method to get a clean data instance without the delta.