final class LWWMap[A] extends ReplicatedData 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, ReplicatedData, AnyRef, Any
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Inherited
  1. LWWMap
  2. RemovedNodePruning
  3. ReplicatedDataSerialization
  4. Serializable
  5. Serializable
  6. ReplicatedData
  7. AnyRef
  8. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Type Members

  1. type T = LWWMap[A]

    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: (String, A))(implicit node: Cluster): LWWMap[A]

    Adds an entry to the map

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

    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.

  3. def contains(key: String): Boolean
  4. def entries: Map[String, A]

    Scala API: All entries of the map.

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

    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]): LWWMap[A]

    Monotonic merge function.

    Monotonic merge function.

    Definition Classes
    LWWMap → ReplicatedData
  11. 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
  12. def prune(removedNode: UniqueAddress, collapseInto: UniqueAddress): LWWMap[A]

    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
  13. def pruningCleanup(removedNode: UniqueAddress): LWWMap[A]

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

    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.

  15. def put(node: Cluster, key: String, value: A, clock: Clock[A]): LWWMap[A]

    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.

  16. def put(node: Cluster, key: String, value: A): LWWMap[A]

    Adds an entry to the map

  17. def remove(node: Cluster, key: String): LWWMap[A]

    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.

  18. def size: Int
  19. def toString(): String
    Definition Classes
    LWWMap → AnyRef → Any