final class ORSet[A] extends DeltaReplicatedData with ReplicatedDataSerialization with RemovedNodePruning with FastMerge
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 the node -> 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.
- Annotations
- @SerialVersionUID()
- Source
- ORSet.scala
- Alphabetic
- By Inheritance
- ORSet
- FastMerge
- RemovedNodePruning
- ReplicatedDataSerialization
- Serializable
- DeltaReplicatedData
- ReplicatedData
- AnyRef
- Any
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
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- Public
- Protected
Type Members
- 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 exampleGSet
uses the same type andORSet
uses different types.- Definition Classes
- ORSet → DeltaReplicatedData
- type T = ORSet[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
- ORSet → ReplicatedData
Value Members
- final def !=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- final def ##: Int
- Definition Classes
- AnyRef → Any
- def ->[B](y: B): (ORSet[A], B)
- def :+(element: A)(implicit node: SelfUniqueAddress): ORSet[A]
Adds an element to the set.
- final def ==(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- def add(node: SelfUniqueAddress, element: A): ORSet[A]
Adds an element to the set.
- final def asInstanceOf[T0]: T0
- Definition Classes
- Any
- def clear(node: SelfUniqueAddress): ORSet[A]
Removes all elements from the set, but keeps the history.
Removes all elements from the set, but keeps the history. This has the same result as using ORSet#remove(node:org\.apache\.pekko\.cluster\.ddata\.SelfUniqueAddress* for each element, but it is more efficient.
- def clone(): AnyRef
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.CloneNotSupportedException]) @HotSpotIntrinsicCandidate() @native()
- def contains(a: A): Boolean
- val delta: Option[DeltaOp]
The accumulated delta of mutator operations since previous #resetDelta.
The accumulated delta of mutator operations since previous #resetDelta. When the
Replicator
invokes themodify
function of theUpdate
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 theReplicator
with the #delta accessor. Themodify
function shall still return the full state in the same way asReplicatedData
without support for deltas.- Definition Classes
- ORSet → DeltaReplicatedData
- def elements: Set[A]
Scala API
- def ensuring(cond: (ORSet[A]) => Boolean, msg: => Any): ORSet[A]
- def ensuring(cond: (ORSet[A]) => Boolean): ORSet[A]
- def ensuring(cond: Boolean, msg: => Any): ORSet[A]
- def ensuring(cond: Boolean): ORSet[A]
- final def eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def equals(o: Any): Boolean
- Definition Classes
- ORSet → AnyRef → Any
- final def getClass(): Class[_ <: AnyRef]
- Definition Classes
- AnyRef → Any
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- def getElements(): Set[A]
Java API
- def hashCode(): Int
- Definition Classes
- ORSet → AnyRef → Any
- def isEmpty: Boolean
- final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- def merge(that: ORSet[A]): ORSet[A]
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.
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
- Definition Classes
- ORSet → ReplicatedData
- def mergeDelta(thatDelta: DeltaOp): ORSet[A]
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 stateT
this method can be implemented by delegating tomerge
.- Definition Classes
- ORSet → DeltaReplicatedData
- 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
- ORSet → RemovedNodePruning
- final def ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- 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
- ORSet → RemovedNodePruning
- final def notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- final def notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @HotSpotIntrinsicCandidate() @native()
- def prune(removedNode: UniqueAddress, collapseInto: UniqueAddress): ORSet[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
- ORSet → RemovedNodePruning
- def pruningCleanup(removedNode: UniqueAddress): ORSet[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
- ORSet → RemovedNodePruning
- def remove(node: SelfUniqueAddress, element: A): ORSet[A]
Java API Removes an element from the set.
- def remove(element: A)(implicit node: SelfUniqueAddress): ORSet[A]
Scala API Removes an element from the set.
- def resetDelta: ORSet[A]
Reset collection of deltas from mutator operations.
Reset collection of deltas from mutator operations. When the
Replicator
invokes themodify
function of theUpdate
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 theReplicator
with the #delta accessor. When theReplicator
has grabbed thedelta
it will invoke this method to get a clean data instance without the delta.- Definition Classes
- ORSet → DeltaReplicatedData
- def size: Int
- final def synchronized[T0](arg0: => T0): T0
- Definition Classes
- AnyRef
- def toString(): String
- Definition Classes
- ORSet → AnyRef → Any
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException]) @native()
- final def wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
Shadowed Implicit Value Members
- def +(other: String): String
- Implicit
- This member is added by an implicit conversion from ORSet[A] toany2stringadd[ORSet[A]] performed by method any2stringadd in scala.Predef.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(oRSet: any2stringadd[ORSet[A]]).+(other)
- Definition Classes
- any2stringadd
Deprecated Value Members
- def +(element: A)(implicit node: Cluster): ORSet[A]
- Annotations
- @deprecated
- Deprecated
(Since version Akka 2.5.20) Use
:+
that takes aSelfUniqueAddress
parameter instead.
- def -(element: A)(implicit node: Cluster): ORSet[A]
Removes an element from the set.
Removes an element from the set.
- Annotations
- @deprecated
- Deprecated
(Since version Akka 2.5.20) Use
remove
that takes aSelfUniqueAddress
parameter instead.
- def add(node: Cluster, element: A): ORSet[A]
- Annotations
- @deprecated
- Deprecated
(Since version Akka 2.5.20) Use
add
that takes aSelfUniqueAddress
parameter instead.
- def clear(node: Cluster): ORSet[A]
- Annotations
- @deprecated
- Deprecated
(Since version Akka 2.5.20) Use
remove
that takes aSelfUniqueAddress
parameter instead.
- def finalize(): Unit
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable]) @Deprecated
- Deprecated
(Since version 9)
- def formatted(fmtstr: String): String
- Implicit
- This member is added by an implicit conversion from ORSet[A] toStringFormat[ORSet[A]] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.12.16) Use
formatString.format(value)
instead ofvalue.formatted(formatString)
, or use thef""
string interpolator. In Java 15 and later,formatted
resolves to the new method in String which has reversed parameters.
- def remove(node: Cluster, element: A): ORSet[A]
Removes an element from the set.
Removes an element from the set.
- Annotations
- @deprecated
- Deprecated
(Since version Akka 2.5.20) Use
remove
that takes aSelfUniqueAddress
parameter instead.
- def →[B](y: B): (ORSet[A], B)
- Implicit
- This member is added by an implicit conversion from ORSet[A] toArrowAssoc[ORSet[A]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use
->
instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.