akka.persistence.multidc.crdt

Class VersionVector

java.lang.Object

akka.persistence.multidc.crdt.VersionVector

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

ManyVersionVector, OneVersionVector

public abstract class VersionVector
extends java.lang.Object
implements scala.Serializable

Representation of a Vector-based clock (counting clock), inspired by Lamport logical clocks.

 Reference:
    1) Leslie Lamport (1978). "Time, clocks, and the ordering of events in a distributed system". Communications of the ACM 21 (7): 558-565.
    2) Friedemann Mattern (1988). "Virtual Time and Global States of Distributed Systems". Workshop on Parallel and Distributed Algorithms: pp. 215-226
 

Based on akka.cluster.ddata.VersionVector.

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

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	VersionVector.After$
static class	VersionVector.Before$
static class	VersionVector.Concurrent$
static interface	VersionVector.Ordering
static class	VersionVector.Same$
static class	VersionVector.Timestamp$ INTERNAL API

Constructor Summary

Constructors

Constructor and Description
VersionVector()

Method Summary

Modifier and Type	Method and Description
boolean	$eq$eq(VersionVector that) Returns true if this VersionVector has the same history as the 'that' VersionVector else false.
boolean	$greater(VersionVector that) Returns true if this is after that else false.
boolean	$less(VersionVector that) Returns true if this is before that else false.
boolean	$less$greater(VersionVector that) Returns true if this and that are concurrent else false.
VersionVector	$plus(java.lang.String key) Increment the version for the key passed as argument.
static VersionVector.After$	AfterInstance() Java API: The VersionVector.After instance
static VersionVector	apply()
static VersionVector	apply(scala.collection.immutable.List<scala.Tuple2<java.lang.String,java.lang.Object>> versions) INTERNAL API
static VersionVector	apply(java.lang.String key, long version)
static VersionVector	apply(scala.collection.immutable.TreeMap<java.lang.String,java.lang.Object> versions)
static VersionVector.Before$	BeforeInstance() Java API: The VersionVector.Before instance
VersionVector.Ordering	compareTo(VersionVector that) Compare two version vectors.
static VersionVector.Concurrent$	ConcurrentInstance() Java API: The VersionVector.Concurrent instance
abstract boolean	contains(java.lang.String key) INTERNAL API
static VersionVector	create() Java API
static VersionVector	empty()
abstract VersionVector	increment(java.lang.String key) Increment the version for the key passed as argument.
abstract boolean	isEmpty()
abstract VersionVector	merge(VersionVector that)
static VersionVector.Same$	SameInstance() Java API: The VersionVector.Same instance
abstract int	size() INTERNAL API
abstract VersionVector	updated(java.lang.String key, long version)
abstract long	versionAt(java.lang.String key)
abstract scala.collection.Iterator<scala.Tuple2<java.lang.String,java.lang.Object>>	versionsIterator() INTERNAL API

Methods inherited from class java.lang.Object

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

Constructor Detail

VersionVector

public VersionVector()

Method Detail

empty

public static VersionVector empty()

apply

public static VersionVector apply()

apply

public static VersionVector apply(scala.collection.immutable.TreeMap<java.lang.String,java.lang.Object> versions)

apply

public static VersionVector apply(java.lang.String key,
                                  long version)

apply

public static VersionVector apply(scala.collection.immutable.List<scala.Tuple2<java.lang.String,java.lang.Object>> versions)

INTERNAL API

create

public static VersionVector create()

Java API

Returns:

(undocumented)

AfterInstance

public static VersionVector.After$ AfterInstance()

Java API: The VersionVector.After instance

Returns:

(undocumented)

BeforeInstance

public static VersionVector.Before$ BeforeInstance()

Java API: The VersionVector.Before instance

Returns:

(undocumented)

SameInstance

public static VersionVector.Same$ SameInstance()

Java API: The VersionVector.Same instance

Returns:

(undocumented)

ConcurrentInstance

public static VersionVector.Concurrent$ ConcurrentInstance()

Java API: The VersionVector.Concurrent instance

Returns:

(undocumented)

$plus

public VersionVector $plus(java.lang.String key)

Increment the version for the key passed as argument. Returns a new VersionVector.

Parameters:

key - (undocumented)

Returns:

(undocumented)

increment

public abstract VersionVector increment(java.lang.String key)

Increment the version for the key passed as argument. Returns a new VersionVector.

Parameters:

key - (undocumented)

Returns:

(undocumented)

updated

public abstract VersionVector updated(java.lang.String key,
                                      long version)

isEmpty

public abstract boolean isEmpty()

size

public abstract int size()

INTERNAL API

Returns:

(undocumented)

versionAt

public abstract long versionAt(java.lang.String key)

contains

public abstract boolean contains(java.lang.String key)

INTERNAL API

Parameters:

key - (undocumented)

Returns:

(undocumented)

$less$greater

public boolean $less$greater(VersionVector that)

Returns true if this and that are concurrent else false.

Parameters:

that - (undocumented)

Returns:

(undocumented)

$less

public boolean $less(VersionVector that)

Returns true if this is before that else false.

Parameters:

that - (undocumented)

Returns:

(undocumented)

$greater

public boolean $greater(VersionVector that)

Returns true if this is after that else false.

Parameters:

that - (undocumented)

Returns:

(undocumented)

$eq$eq

public boolean $eq$eq(VersionVector that)

Returns true if this VersionVector has the same history as the 'that' VersionVector else false.

Parameters:

that - (undocumented)

Returns:

(undocumented)

versionsIterator

public abstract scala.collection.Iterator<scala.Tuple2<java.lang.String,java.lang.Object>> versionsIterator()

INTERNAL API

Returns:

(undocumented)

compareTo

public VersionVector.Ordering compareTo(VersionVector that)

Compare two version vectors. The outcome will be one of the following:

   1. Version 1 is SAME (==)       as Version 2 iff for all i c1(i) == c2(i)
   2. Version 1 is BEFORE (<)      Version 2 iff for all i c1(i) <= c2(i) and there exist a j such that c1(j) < c2(j)
   3. Version 1 is AFTER (>)       Version 2 iff for all i c1(i) >= c2(i) and there exist a j such that c1(j) > c2(j).
   4. Version 1 is CONCURRENT (<>) to Version 2 otherwise.
 

Parameters:

that - (undocumented)

Returns:

(undocumented)

merge

public abstract VersionVector merge(VersionVector that)