Class GCounter

Implements a 'Growing Counter' CRDT, also called a 'G-Counter'.

It is described in the paper A comprehensive study of Convergent and Commutative Replicated Data Types.

A G-Counter is a increment-only counter (inspired by vector clocks) in which only increment and merge are possible. Incrementing the counter adds 1 to the count for the current node. Divergent histories are resolved by taking the maximum count for each node (like a vector clock merge). The value of the counter is the sum of all node counts.

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

Inheritance
object
FastMerge<GCounter>
GCounter
Implements
Inherited Members
Namespace: Akka.DistributedData
Assembly: Akka.DistributedData.dll
Syntax
[Serializable]
public sealed class GCounter : FastMerge<GCounter>, IRemovedNodePruning<GCounter>, IRemovedNodePruning, IEquatable<GCounter>, IReplicatedDataSerialization, IDeltaReplicatedData<GCounter, GCounter>, IDeltaReplicatedData, IReplicatedData<GCounter>, IReplicatedDelta, IReplicatedData

Constructors

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GCounter()

TBD

Declaration
public GCounter()

Properties

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Delta

The accumulated delta of mutator operations since previous ResetDelta(). When the Akka.DistributedData.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 Akka.DistributedData.Replicator with the Delta accessor. The modify function shall still return the full state in the same way as IReplicatedData<T> without support for deltas.

Declaration
public GCounter Delta { get; }
Property Value
Type Description
GCounter
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Empty

TBD

Declaration
public static GCounter Empty { get; }
Property Value
Type Description
GCounter
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ModifiedByNodes

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

Declaration
public ImmutableHashSet<UniqueAddress> ModifiedByNodes { get; }
Property Value
Type Description
ImmutableHashSet<UniqueAddress>
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State

TBD

Declaration
public ImmutableDictionary<UniqueAddress, ulong> State { get; }
Property Value
Type Description
ImmutableDictionary<UniqueAddress, ulong>
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Value

Current total value of the counter.

Declaration
public ulong Value { get; }
Property Value
Type Description
ulong

Methods

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Equals(GCounter)

Declaration
public bool Equals(GCounter other)
Parameters
Type Name Description
GCounter other
Returns
Type Description
bool
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Equals(object)

Declaration
public override bool Equals(object obj)
Parameters
Type Name Description
object obj
Returns
Type Description
bool
Overrides
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GetHashCode()

Declaration
public override int GetHashCode()
Returns
Type Description
int
Overrides
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Increment(Cluster, ulong)

Increment the counter with the delta specified. The delta must be zero or positive.

Declaration
public GCounter Increment(Cluster node, ulong delta = 1)
Parameters
Type Name Description
Cluster node
ulong delta
Returns
Type Description
GCounter
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Increment(UniqueAddress, ulong)

Increment the counter with the delta specified. The delta must be zero or positive.

Declaration
public GCounter Increment(UniqueAddress node, ulong n = 1)
Parameters
Type Name Description
UniqueAddress node

TBD
ulong n

TBD
Returns
Type Description
GCounter

TBD
Exceptions
Type Condition
ArgumentException

This exception is thrown when the specified n is less than zero.
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Merge(GCounter)

TBD

Declaration
public override GCounter Merge(GCounter other)
Parameters
Type Name Description
GCounter other

TBD
Returns
Type Description
GCounter

TBD
Overrides
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MergeDelta(GCounter)

When delta is merged into the full state this method is used. When the type GCounter of the delta is of the same type as the full state GCounter this method can be implemented by delegating to Merge(T).

Declaration
public GCounter MergeDelta(GCounter delta)
Parameters
Type Name Description
GCounter delta
Returns
Type Description
GCounter
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NeedPruningFrom(UniqueAddress)

TBD

Declaration
public bool NeedPruningFrom(UniqueAddress removedNode)
Parameters
Type Name Description
UniqueAddress removedNode

TBD
Returns
Type Description
bool

TBD
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Prune(UniqueAddress, UniqueAddress)

TBD

Declaration
public GCounter Prune(UniqueAddress removedNode, UniqueAddress collapseInto)
Parameters
Type Name Description
UniqueAddress removedNode

TBD
UniqueAddress collapseInto

TBD
Returns
Type Description
GCounter

TBD
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PruningCleanup(UniqueAddress)

TBD

Declaration
public GCounter PruningCleanup(UniqueAddress removedNode)
Parameters
Type Name Description
UniqueAddress removedNode

TBD
Returns
Type Description
GCounter

TBD
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ResetDelta()

Reset collection of deltas from mutator operations. When the Akka.DistributedData.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 Akka.DistributedData.Replicator with the Delta accessor. When the Akka.DistributedData.Replicator has grabbed the Delta it will invoke this method to get a clean data instance without the delta.

Declaration
public GCounter ResetDelta()
Returns
Type Description
GCounter
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ToString()

Declaration
public override string ToString()
Returns
Type Description
string
Overrides

Operators

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implicit operator ulong(GCounter)

Performs an implicit conversion from GCounter to ulong.

Declaration
public static implicit operator ulong(GCounter counter)
Parameters
Type Name Description
GCounter counter

The counter to convert
Returns
Type Description
ulong

The result of the conversion

Implements

Extension Methods