Package akka.cluster.ddata

Class ORSet<A>

    • Method Detail

      • $lessinit$greater$default$3

        public static <A> scala.Option<ORSet.DeltaOp> $lessinit$greater$default$3()
        Implements a 'Observed Remove Set' CRDT, also called a 'OR-Set'. Elements can be added and removed any number of times. Concurrent add wins over remove.

        It is not implemented as in the paper A comprehensive study of Convergent and Commutative Replicated Data Types. This is more space efficient and doesn't accumulate garbage for removed elements. It is described in the paper An optimized conflict-free replicated set The implementation is inspired by the Riak DT riak_dt_orswot.

        The ORSet has a version vector that is incremented when an element is added to the set. The node -&gt; count pair for that increment is stored against the element as its "birth dot". Every time the element is re-added to the set, its "birth dot" is updated to that of the node -&gt; count version vector entry resulting from the add. When an element is removed, we simply drop it, no tombstones.

        When an element exists in replica A and not replica B, is it because A added it and B has not yet seen that, or that B removed it and A has not yet seen that? In this implementation we compare the dot of the present element to the version vector in the Set it is absent from. If the element dot is not "seen" by the Set version vector, that means the other set has yet to see this add, and the item is in the merged Set. If the Set version vector dominates the dot, that means the other Set has removed this element already, and the item is not in the merged Set.

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

        Returns:
        (undocumented)

      • empty

        public static <A> ORSet<A> empty()

      • apply

        public static ORSet<java.lang.Object> apply()

      • create

        public static <A> ORSet<A> create()
        Java API
        Returns:
        (undocumented)

      • unapply

        public static <A> scala.Option<scala.collection.immutable.Set<A>> unapply​(ORSet<A> s)
        Extract the elements().
        Parameters:
        s - (undocumented)
        Returns:
        (undocumented)

      • unapply

        public static scala.Option<scala.collection.immutable.Set<java.lang.Object>> unapply​(ReplicatedData a)
        Extract the elements() of an ORSet.
        Parameters:
        a - (undocumented)
        Returns:
        (undocumented)

      • mergeCommonKeys

        public static <A> scala.collection.immutable.Map<A,​VersionVector> mergeCommonKeys​(scala.collection.immutable.Set<A> commonKeys,
                                                                                        ORSet<A> lhs,
                                                                                        ORSet<A> rhs)

      • mergeDisjointKeys

        public static <A> scala.collection.immutable.Map<A,​VersionVector> mergeDisjointKeys​(scala.collection.immutable.Set<A> keys,
                                                                                          scala.collection.immutable.Map<A,​VersionVector> elementsMap,
                                                                                          VersionVector vvector,
                                                                                          scala.collection.immutable.Map<A,​VersionVector> accumulator)

      • elementsMap

        public scala.collection.immutable.Map<A,​VersionVector> elementsMap()

      • delta

        public scala.Option<ORSet.DeltaOp> delta()
        Description copied from interface: DeltaReplicatedData
        The accumulated delta of mutator operations since previous DeltaReplicatedData.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 DeltaReplicatedData.delta() accessor. The modify function shall still return the full state in the same way as ReplicatedData without support for deltas.
        Specified by:
        delta in interface DeltaReplicatedData
        Returns:
        (undocumented)

      • elements

        public scala.collection.immutable.Set<A> elements()
        Scala API
        Returns:
        (undocumented)

      • getElements

        public java.util.Set<A> getElements()
        Java API
        Returns:
        (undocumented)

      • contains

        public boolean contains​(A a)

      • isEmpty

        public boolean isEmpty()

      • size

        public int size()

      • $plus

        public ORSet<A> $plus​(A element,
                      Cluster node)
        Deprecated.
        Use `:+` that takes a `SelfUniqueAddress` parameter instead. Since 2.5.20.

      • add

        public ORSet<A> add​(Cluster node,
                    A element)
        Deprecated.
        Use `add` that takes a `SelfUniqueAddress` parameter instead. Since 2.5.20.

      • add

        public ORSet<A> add​(UniqueAddress node,
                    A element)
        INTERNAL API
        Parameters:
        node - (undocumented)
        element - (undocumented)
        Returns:
        (undocumented)

      • remove

        public ORSet<A> remove​(A element,
                       SelfUniqueAddress node)
        Scala API Removes an element from the set.
        Parameters:
        element - (undocumented)
        node - (undocumented)
        Returns:
        (undocumented)

      • remove

        public ORSet<A> remove​(SelfUniqueAddress node,
                       A element)
        Java API Removes an element from the set.
        Parameters:
        node - (undocumented)
        element - (undocumented)
        Returns:
        (undocumented)

      • $minus

        public ORSet<A> $minus​(A element,
                       Cluster node)
        Deprecated.
        Use `remove` that takes a `SelfUniqueAddress` parameter instead. Since 2.5.20.
        Removes an element from the set.
        Parameters:
        element - (undocumented)
        node - (undocumented)
        Returns:
        (undocumented)

      • remove

        public ORSet<A> remove​(Cluster node,
                       A element)
        Deprecated.
        Use `remove` that takes a `SelfUniqueAddress` parameter instead. Since 2.5.20.
        Removes an element from the set.
        Parameters:
        node - (undocumented)
        element - (undocumented)
        Returns:
        (undocumented)

      • remove

        public ORSet<A> remove​(UniqueAddress node,
                       A element)
        INTERNAL API
        Parameters:
        node - (undocumented)
        element - (undocumented)
        Returns:
        (undocumented)

      • clear

        public ORSet<A> clear​(SelfUniqueAddress node)
        Removes all elements from the set, but keeps the history. This has the same result as using {@link ORSet#remove(node:akka\.cluster\.ddata\.SelfUniqueAddress*} for each element, but it is more efficient.
        Parameters:
        node - (undocumented)
        Returns:
        (undocumented)

      • clear

        public ORSet<A> clear​(Cluster node)
        Deprecated.
        Use `remove` that takes a `SelfUniqueAddress` parameter instead. Since 2.5.20.

      • clear

        public ORSet<A> clear()
        INTERNAL API
        Returns:
        (undocumented)

      • merge

        public ORSet<A> merge​(ORSet<A> that)
        When element is in this Set but not in that Set: Compare the "birth dot" of the present element to the version vector in the Set it is absent from. If the element dot is not "seen" by other Set version vector, that means the other set has yet to see this add, and the element is to be in the merged Set. If the other Set version vector dominates the dot, that means the other Set has removed the element already, and the element is not to be in the merged Set.

        When element in both this Set and in that Set: Some dots may still need to be shed. If this Set has dots that the other Set does not have, and the other Set version vector dominates those dots, then we need to drop those dots. Keep only common dots, and dots that are not dominated by the other sides version vector

        Parameters:
        that - (undocumented)
        Returns:
        (undocumented)

      • resetDelta

        public ORSet<A> resetDelta()
        Description copied from interface: DeltaReplicatedData
        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 DeltaReplicatedData.delta() accessor. When the Replicator has grabbed the delta it will invoke this method to get a clean data instance without the delta.
        Specified by:
        resetDelta in interface DeltaReplicatedData
        Returns:
        (undocumented)

      • needPruningFrom

        public boolean needPruningFrom​(UniqueAddress removedNode)
        Description copied from interface: RemovedNodePruning
        Does it have any state changes from a specific node, which has been removed from the cluster.
        Specified by:
        needPruningFrom in interface RemovedNodePruning
        Parameters:
        removedNode - (undocumented)
        Returns:
        (undocumented)

      • prune

        public ORSet<A> prune​(UniqueAddress removedNode,
                      UniqueAddress collapseInto)
        Description copied from interface: RemovedNodePruning
        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.
        Specified by:
        prune in interface RemovedNodePruning
        Parameters:
        removedNode - (undocumented)
        collapseInto - (undocumented)
        Returns:
        (undocumented)

      • pruningCleanup

        public ORSet<A> pruningCleanup​(UniqueAddress removedNode)
        Description copied from interface: RemovedNodePruning
        Remove data entries from a node that has been removed from the cluster and already been pruned.
        Specified by:
        pruningCleanup in interface RemovedNodePruning
        Parameters:
        removedNode - (undocumented)
        Returns:
        (undocumented)

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • equals

        public boolean equals​(java.lang.Object o)
        Overrides:
        equals in class java.lang.Object

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class java.lang.Object