final class LWWMap[A, B] extends DeltaReplicatedData with ReplicatedDataSerialization with RemovedNodePruning

Specialized ORMap with LWWRegister values.

LWWRegister relies on synchronized clocks and should only be used when the choice of value is not important for concurrent updates occurring within the clock skew.

Instead of using timestamps based on System.currentTimeMillis() time it is possible to use a timestamp value based on something else, for example an increasing version number from a database record that is used for optimistic concurrency control.

The defaultClock is using max value of System.currentTimeMillis() and currentTimestamp + 1. This means that the timestamp is increased for changes on the same node that occurs within the same millisecond. It also means that it is safe to use the LWWMap without synchronized clocks when there is only one active writer, e.g. a Cluster Singleton. Such a single writer should then first read current value with ReadMajority (or more) before changing and writing the value with WriteMajority (or more).

For first-write-wins semantics you can use the LWWRegister#reverseClock instead of the LWWRegister#defaultClock

This class is immutable, i.e. "modifying" methods return a new instance.

Annotations
@SerialVersionUID()
Source
LWWMap.scala
Linear Supertypes
RemovedNodePruning, ReplicatedDataSerialization, Serializable, Serializable, DeltaReplicatedData, ReplicatedData, AnyRef, Any
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Inherited
  1. LWWMap
  2. RemovedNodePruning
  3. ReplicatedDataSerialization
  4. Serializable
  5. Serializable
  6. DeltaReplicatedData
  7. ReplicatedData
  8. AnyRef
  9. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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  1. Public
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Type Members

  1. type D = DeltaOp

    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.

    Definition Classes
    LWWMap → DeltaReplicatedData
  2. type T = LWWMap[A, B]

    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
    LWWMap → ReplicatedData

Value Members

  1. def :+(entry: (A, B))(implicit node: SelfUniqueAddress): LWWMap[A, B]

    Adds an entry to the map

  2. def contains(key: A): Boolean
  3. 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.

    Definition Classes
    LWWMap → DeltaReplicatedData
  4. def entries: Map[A, B]

    Scala API: All entries of the map.

  5. def equals(o: Any): Boolean
    Definition Classes
    LWWMap → AnyRef → Any
  6. def get(key: A): Option[B]
  7. def getEntries(): Map[A, B]

    Java API: All entries of the map.

  8. def hashCode(): Int
    Definition Classes
    LWWMap → AnyRef → Any
  9. def isEmpty: Boolean
  10. def merge(that: LWWMap[A, B]): LWWMap[A, B]

    Monotonic merge function.

    Monotonic merge function.

    Definition Classes
    LWWMap → ReplicatedData
  11. def mergeDelta(thatDelta: D): LWWMap[A, B]

    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.

    Definition Classes
    LWWMap → DeltaReplicatedData
  12. def modifiedByNodes: Set[UniqueAddress]

    The nodes that have changed the state for this data and would need pruning when such node is no longer part of the cluster.

    The nodes that have changed the state for this data and would need pruning when such node is no longer part of the cluster.

    Definition Classes
    LWWMap → RemovedNodePruning
  13. def needPruningFrom(removedNode: UniqueAddress): Boolean

    Does it have any state changes from a specific node, which has been removed from the cluster.

    Does it have any state changes from a specific node, which has been removed from the cluster.

    Definition Classes
    LWWMap → RemovedNodePruning
  14. def prune(removedNode: UniqueAddress, collapseInto: UniqueAddress): LWWMap[A, B]

    When the removed node has been removed from the cluster the state changes from that node will be pruned by collapsing the data entries to another node.

    When the removed node has been removed from the cluster the state changes from that node will be pruned by collapsing the data entries to another node.

    Definition Classes
    LWWMap → RemovedNodePruning
  15. def pruningCleanup(removedNode: UniqueAddress): LWWMap[A, B]

    Remove data entries from a node that has been removed from the cluster and already been pruned.

    Remove data entries from a node that has been removed from the cluster and already been pruned.

    Definition Classes
    LWWMap → RemovedNodePruning
  16. def put(node: SelfUniqueAddress, key: A, value: B, clock: Clock[B]): LWWMap[A, B]

    Adds an entry to the map.

    Adds an entry to the map.

    You can provide your clock implementation instead of using timestamps based on System.currentTimeMillis() time. The timestamp can for example be an increasing version number from a database record that is used for optimistic concurrency control.

  17. def put(node: SelfUniqueAddress, key: A, value: B): LWWMap[A, B]

    Adds an entry to the map

  18. def remove(node: SelfUniqueAddress, key: A): LWWMap[A, B]

    Removes an entry from the map.

    Removes an entry from the map. Note that if there is a conflicting update on another node the entry will not be removed after merge.

  19. def resetDelta: LWWMap[A, B]

    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.

    Definition Classes
    LWWMap → DeltaReplicatedData
  20. def size: Int
  21. def toString(): String
    Definition Classes
    LWWMap → AnyRef → Any

Deprecated Value Members

  1. def +(entry: (A, B))(implicit node: Cluster): LWWMap[A, B]
    Annotations
    @deprecated
    Deprecated

    (Since version 2.5.20) Use :+ that takes a SelfUniqueAddress parameter instead.

  2. def -(key: A)(implicit node: Cluster): LWWMap[A, B]

    Removes an entry from the map.

    Removes an entry from the map. Note that if there is a conflicting update on another node the entry will not be removed after merge.

    Annotations
    @deprecated
    Deprecated

    (Since version 2.5.20) Use remove that takes a SelfUniqueAddress parameter instead.

  3. def put(key: A, value: B)(implicit node: Cluster, clock: Clock[B] = defaultClock[B]): LWWMap[A, B]

    Adds an entry to the map.

    Adds an entry to the map.

    You can provide your clock implementation instead of using timestamps based on System.currentTimeMillis() time. The timestamp can for example be an increasing version number from a database record that is used for optimistic concurrency control.

    Annotations
    @deprecated
    Deprecated

    (Since version 2.5.20) Use put that takes a SelfUniqueAddress parameter instead.

  4. def put(node: Cluster, key: A, value: B, clock: Clock[B]): LWWMap[A, B]
    Annotations
    @deprecated
    Deprecated

    (Since version 2.5.20) Use put that takes a SelfUniqueAddress parameter instead.

  5. def put(node: Cluster, key: A, value: B): LWWMap[A, B]
    Annotations
    @deprecated
    Deprecated

    (Since version 2.5.20) Use put that takes a SelfUniqueAddress parameter instead.

  6. def remove(node: Cluster, key: A): LWWMap[A, B]
    Annotations
    @deprecated
    Deprecated

    (Since version 2.5.20) Use remove that takes a SelfUniqueAddress parameter instead.