pt.unl.fct.di.novasys.babel.crdts.delta.implementations

Class DeltaLWWSet

java.lang.Object

pt.unl.fct.di.novasys.babel.crdts.generic.CRDT

pt.unl.fct.di.novasys.babel.crdts.delta.generic.DeltaBasedCRDT

pt.unl.fct.di.novasys.babel.crdts.delta.implementations.DeltaLWWSet

All Implemented Interfaces:

DeltaCRDT, GenericCRDT

public class DeltaLWWSet
extends DeltaBasedCRDT

A delta-based set with a last-writer-wins policy (LWW). The set supports generic types implemented as SerializableTypes. It provides methods to add, remove and lookup for elements.

Field Summary

Fields

Modifier and Type	Field and Description
static pt.unl.fct.di.novasys.network.ISerializer<DeltaLWWSet>	serializer A serializer that serializes the CRDT into (and from) a ByteBuf.
static CRDTsTypes	TYPE

Fields inherited from class pt.unl.fct.di.novasys.babel.crdts.delta.generic.DeltaBasedCRDT

state

Fields inherited from class pt.unl.fct.di.novasys.babel.crdts.generic.CRDT

type

Constructor Summary

Constructors

Constructor and Description
DeltaLWWSet(ReplicaID replicaID)
DeltaLWWSet(ReplicaID replicaID, Set<SerializableType> initialValues)
DeltaLWWSet(VVState state)
DeltaLWWSet(VVState state, Set<SerializableType> initialValues)

Method Summary

Modifier and Type	Method and Description
DeltaLWWSet	add(SerializableType element) Adds an element to the set.
GenericCRDT	copy() Creates a copy of the CRDT.
DeltaLWWSet	generateDelta(VersionVector vv) Calculates a delta from a given version for the current state
Iterator<SerializableType>	iterator() Returns an iterator of the elements in the set.
boolean	lookup(SerializableType element) Searches for the element passed as argument.
DeltaLWWSet	mergeDelta(DeltaBasedCRDT crdt) Applies a delta to the current state.
DeltaLWWSet	remove(SerializableType element) Removes an element of the set.
void	serialize(io.netty.buffer.ByteBuf in) Serializes the CRDT into a ByteBuf

Methods inherited from class pt.unl.fct.di.novasys.babel.crdts.delta.generic.DeltaBasedCRDT

getReplicaID, getReplicaState

Methods inherited from class pt.unl.fct.di.novasys.babel.crdts.generic.CRDT

getType

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface pt.unl.fct.di.novasys.babel.crdts.generic.GenericCRDT

deserializeDataType, getType

Field Detail

TYPE

public static final CRDTsTypes TYPE

serializer

public static pt.unl.fct.di.novasys.network.ISerializer<DeltaLWWSet> serializer

A serializer that serializes the CRDT into (and from) a ByteBuf.

Constructor Detail

DeltaLWWSet

public DeltaLWWSet(ReplicaID replicaID)

DeltaLWWSet

public DeltaLWWSet(VVState state)

DeltaLWWSet

public DeltaLWWSet(ReplicaID replicaID,
                   Set<SerializableType> initialValues)

DeltaLWWSet

public DeltaLWWSet(VVState state,
                   Set<SerializableType> initialValues)

Method Detail

add

public DeltaLWWSet add(SerializableType element)

Adds an element to the set. If the element doesn't exist, it is added. Otherwise, the add is only successful if the current timestamp is greater or equal than the one associated with the element.

Parameters:

element - the element to insert

Returns:

a delta of the operation just performed

remove

public DeltaLWWSet remove(SerializableType element)

Removes an element of the set. If the element doesn't exist, it is added to the remove set. Otherwise, the remove is only successful if the current timestamp is greater or equal than the one associated with the element.

Parameters:

element - the element to insert

Returns:

a delta of the operation just performed

lookup

public boolean lookup(SerializableType element)

Searches for the element passed as argument. Returns true if the element is in the add set and not in the remove set.

Parameters:

element - element to search

Returns:

true if the element is in the add set and not in the remove set, or false otherwise.

iterator

public Iterator<SerializableType> iterator()

Returns an iterator of the elements in the set.

Returns:

an iterator of the elements in the set.

generateDelta

public DeltaLWWSet generateDelta(VersionVector vv)

Description copied from interface: DeltaCRDT

Calculates a delta from a given version for the current state

Specified by:

generateDelta in interface DeltaCRDT

Specified by:

generateDelta in class DeltaBasedCRDT

Parameters:

vv - a version version to calculate the delta from

Returns:

a delta for the current state

mergeDelta

public DeltaLWWSet mergeDelta(DeltaBasedCRDT crdt)
                       throws CRDTNotValidException

Description copied from interface: DeltaCRDT

Applies a delta to the current state. This method is analogous to a merge of states

Specified by:

mergeDelta in interface DeltaCRDT

Specified by:

mergeDelta in class DeltaBasedCRDT

Parameters:

crdt - a crdt representing the delta

Returns:

the current state

Throws:

CRDTNotValidException - if the crdt passed as argument is invalid

copy

public GenericCRDT copy()

Description copied from interface: GenericCRDT

Creates a copy of the CRDT. Modifications on the copy don't modify the original.

Returns:

a copy of the CRDT

serialize

public void serialize(io.netty.buffer.ByteBuf in)
               throws IOException

Description copied from interface: GenericCRDT

Serializes the CRDT into a ByteBuf

Parameters:

in - ByteBuf to serialize the CRDT to

Throws:

IOException - if an error occurs while serializing