java.lang.Object
- akka.cluster.ddata.PNCounter

All Implemented Interfaces:

DeltaReplicatedData, RemovedNodePruning, ReplicatedData, ReplicatedDataSerialization, ReplicatedDelta, java.io.Serializable
```
public final class PNCounter
extends java.lang.Object
implements DeltaReplicatedData, ReplicatedDelta, ReplicatedDataSerialization, RemovedNodePruning
```
Implements a 'Increment/Decrement Counter' CRDT, also called a 'PN-Counter'.
It is described in the paper A comprehensive study of Convergent and Commutative Replicated Data Types.
PN-Counters allow the counter to be incremented by tracking the increments (P) separate from the decrements (N). Both P and N are represented as two internal GCounters. Merge is handled by merging the internal P and N counters. The value of the counter is the value of the P counter minus the value of the N counter.
This class is immutable, i.e. "modifying" methods return a new instance.

See Also:

Serialized Form

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`PNCounter`	`$colon$plus(long n, SelfUniqueAddress node)`	Increment the counter with the delta `n` specified.
`PNCounter`	`$colon$plus(scala.math.BigInt n, SelfUniqueAddress node)`	Increment the counter with the delta `n` specified.
`static PNCounter`	`apply()`
`static PNCounter`	`create()`	Java API
`PNCounter`	`decrement(long n, SelfUniqueAddress node)`	Decrement the counter with the delta `n` specified.
`PNCounter`	`decrement(SelfUniqueAddress node, long n)`	Decrement the counter with the delta `n` specified.
`PNCounter`	`decrement(SelfUniqueAddress node, java.math.BigInteger n)`	Java API: Decrement the counter with the delta `n` specified.
`PNCounter`	`decrement(SelfUniqueAddress node, scala.math.BigInt n)`	Scala API: Decrement the counter with the delta `n` specified.
`PNCounter`	`decrement(scala.math.BigInt n, SelfUniqueAddress node)`	Decrement the counter with the delta `n` specified.
`scala.Option<PNCounter>`	`delta()`	The accumulated delta of mutator operations since previous `DeltaReplicatedData.resetDelta()`.
`static PNCounter`	`empty()`
`boolean`	`equals(java.lang.Object o)`
`java.math.BigInteger`	`getValue()`	Java API: Current total value of the counter.
`int`	`hashCode()`
`PNCounter`	`increment(long n, SelfUniqueAddress node)`	Scala API: Increment the counter with the delta `n` specified.
`PNCounter`	`increment(SelfUniqueAddress node, long n)`	Java API: Increment the counter with the delta `n` specified.
`PNCounter`	`increment(SelfUniqueAddress node, java.math.BigInteger n)`	Java API: Increment the counter with the delta `n` specified.
`PNCounter`	`increment(scala.math.BigInt n, SelfUniqueAddress node)`	Increment the counter with the delta `n` specified.
`PNCounter`	`merge(PNCounter that)`
`PNCounter`	`mergeDelta(PNCounter thatDelta)`
`scala.collection.immutable.Set<UniqueAddress>`	`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.
`boolean`	`needPruningFrom(UniqueAddress removedNode)`	Does it have any state changes from a specific node, which has been removed from the cluster.
`PNCounter`	`prune(UniqueAddress removedNode, UniqueAddress collapseInto)`	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.
`PNCounter`	`pruningCleanup(UniqueAddress removedNode)`	Remove data entries from a node that has been removed from the cluster and already been pruned.
`PNCounter`	`resetDelta()`	Reset collection of deltas from mutator operations.
`java.lang.String`	`toString()`
`static scala.Option<scala.math.BigInt>`	`unapply(PNCounter c)`	Extract the `GCounter.value()`.
`scala.math.BigInt`	`value()`	Scala API: Current total value of the counter.
`PNCounter`	`zero()`	The empty full state.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface akka.cluster.ddata.DeltaReplicatedData
mergeDelta

Methods inherited from interface akka.cluster.ddata.ReplicatedData
merge

- Method Detail
  - empty
```
public static PNCounter empty()
```
  - apply
```
public static PNCounter apply()
```
  - create
```
public static PNCounter create()
```
    Java API
  - unapply
```
public static scala.Option<scala.math.BigInt> unapply(PNCounter c)
```
    Extract the GCounter.value().
  - value
```
public scala.math.BigInt value()
```
    Scala API: Current total value of the counter.
  - getValue
```
public java.math.BigInteger getValue()
```
    Java API: Current total value of the counter.
  - $colon$plus
```
public PNCounter $colon$plus(long n,
                             SelfUniqueAddress node)
```
    Increment the counter with the delta n specified. If the delta is negative then it will decrement instead of increment.
  - $colon$plus
```
public PNCounter $colon$plus(scala.math.BigInt n,
                             SelfUniqueAddress node)
```
    Increment the counter with the delta n specified. If the delta is negative then it will decrement instead of increment.
  - increment
```
public PNCounter increment(long n,
                           SelfUniqueAddress node)
```
    Scala API: Increment the counter with the delta n specified. If the delta is negative then it will decrement instead of increment.
  - increment
```
public PNCounter increment(scala.math.BigInt n,
                           SelfUniqueAddress node)
```
    Increment the counter with the delta n specified. If the delta is negative then it will decrement instead of increment.
  - increment
```
public PNCounter increment(SelfUniqueAddress node,
                           java.math.BigInteger n)
```
    Java API: Increment the counter with the delta n specified. If the delta is negative then it will decrement instead of increment.
  - increment
```
public PNCounter increment(SelfUniqueAddress node,
                           long n)
```
    Java API: Increment the counter with the delta n specified. If the delta is negative then it will decrement instead of increment.
  - decrement
```
public PNCounter decrement(long n,
                           SelfUniqueAddress node)
```
    Decrement the counter with the delta n specified. If the delta is negative then it will increment instead of decrement.
  - decrement
```
public PNCounter decrement(scala.math.BigInt n,
                           SelfUniqueAddress node)
```
    Decrement the counter with the delta n specified. If the delta is negative then it will increment instead of decrement.
  - decrement
```
public PNCounter decrement(SelfUniqueAddress node,
                           long n)
```
    Decrement the counter with the delta n specified. If the delta n is negative then it will increment instead of decrement.
  - decrement
```
public PNCounter decrement(SelfUniqueAddress node,
                           scala.math.BigInt n)
```
    Scala API: Decrement the counter with the delta n specified. If the delta n is negative then it will increment instead of decrement.
  - decrement
```
public PNCounter decrement(SelfUniqueAddress node,
                           java.math.BigInteger n)
```
    Java API: Decrement the counter with the delta n specified. If the delta n is negative then it will increment instead of decrement.
  - merge
```
public PNCounter merge(PNCounter that)
```
  - delta
```
public scala.Option<PNCounter> 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
  - mergeDelta
```
public PNCounter mergeDelta(PNCounter thatDelta)
```
  - zero
```
public PNCounter zero()
```
    Description copied from interface: ReplicatedDelta
    
    The empty full state. This is used when a delta is received and no existing full state exists on the receiving side. Then the delta is merged into the zero to create the initial full state.
    
    Specified by:
    
    zero in interface ReplicatedDelta
  - resetDelta
```
public PNCounter 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
  - modifiedByNodes
```
public scala.collection.immutable.Set<UniqueAddress> modifiedByNodes()
```
    Description copied from interface: RemovedNodePruning
    
    The nodes that have changed the state for this data and would need pruning when such node is no longer part of the cluster.
    
    Specified by:
    
    modifiedByNodes in interface RemovedNodePruning
  - 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
  - prune
```
public PNCounter 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
  - pruningCleanup
```
public PNCounter 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
  - 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

Class PNCounter

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface akka.cluster.ddata.DeltaReplicatedData

Methods inherited from interface akka.cluster.ddata.ReplicatedData

Method Detail

empty

apply

create

unapply

value

getValue

$colon$plus

$colon$plus

increment

increment

increment

increment

decrement

decrement

decrement

decrement

decrement

merge

delta

mergeDelta

zero

resetDelta

modifiedByNodes

needPruningFrom

prune

pruningCleanup

toString

equals

hashCode