Class ORSet$
- java.lang.Object
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- akka.cluster.ddata.ORSet$
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- All Implemented Interfaces:
java.io.Serializable
,scala.Serializable
public class ORSet$ extends java.lang.Object implements scala.Serializable
Java API- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description ORSet$()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description <A> scala.Option<ORSet.DeltaOp>
$lessinit$greater$default$3()
Implements a 'Observed Remove Set' CRDT, also called a 'OR-Set'.ORSet<java.lang.Object>
apply()
<A> ORSet<A>
create()
Java API<A> ORSet<A>
empty()
<A> scala.collection.immutable.Map<A,VersionVector>
mergeCommonKeys(scala.collection.immutable.Set<A> commonKeys, ORSet<A> lhs, ORSet<A> rhs)
<A> scala.collection.immutable.Map<A,VersionVector>
mergeDisjointKeys(scala.collection.immutable.Set<A> keys, scala.collection.immutable.Map<A,VersionVector> elementsMap, VersionVector vvector, scala.collection.immutable.Map<A,VersionVector> accumulator)
VersionVector
subtractDots(VersionVector dot, VersionVector vvector)
<A> scala.Option<scala.collection.immutable.Set<A>>
unapply(ORSet<A> s)
Extract theORSet.elements()
.scala.Option<scala.collection.immutable.Set<java.lang.Object>>
unapply(ReplicatedData a)
Extract theORSet.elements()
of anORSet
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Field Detail
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MODULE$
public static final ORSet$ MODULE$
Static reference to the singleton instance of this Scala object.
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Method Detail
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$lessinit$greater$default$3
public <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 -> 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 thenode -> 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)
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empty
public <A> ORSet<A> empty()
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apply
public ORSet<java.lang.Object> apply()
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create
public <A> ORSet<A> create()
Java API- Returns:
- (undocumented)
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unapply
public <A> scala.Option<scala.collection.immutable.Set<A>> unapply(ORSet<A> s)
Extract theORSet.elements()
.- Parameters:
s
- (undocumented)- Returns:
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unapply
public scala.Option<scala.collection.immutable.Set<java.lang.Object>> unapply(ReplicatedData a)
Extract theORSet.elements()
of anORSet
.- Parameters:
a
- (undocumented)- Returns:
- (undocumented)
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subtractDots
public VersionVector subtractDots(VersionVector dot, VersionVector vvector)
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mergeCommonKeys
public <A> scala.collection.immutable.Map<A,VersionVector> mergeCommonKeys(scala.collection.immutable.Set<A> commonKeys, ORSet<A> lhs, ORSet<A> rhs)
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mergeDisjointKeys
public <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)
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