org.onosproject.store.service

Class Versioned<V>

java.lang.Object

org.onosproject.store.service.Versioned<V>

Type Parameters:

V - value type.

public class Versioned<V>
extends java.lang.Object

Versioned value.

Constructor Summary

Constructors

Constructor and Description
Versioned(V value, long version) Constructs a new versioned value.
Versioned(V value, long version, long creationTime) Constructs a new versioned value.

Method Summary

Modifier and Type	Method and Description
long	creationTime() Returns the system time when this version was created.
boolean	equals(java.lang.Object other)
int	hashCode()
<U> Versioned<U>	map(java.util.function.Function<V,U> transformer) Maps this instance into another after transforming its value while retaining the same version and creationTime.
java.lang.String	toString()
V	value() Returns the value.
static <U> U	valueOrElse(Versioned<U> versioned, U defaultValue) Returns the value of the specified Versioned object if non-null or else returns a default value.
static <U> U	valueOrNull(Versioned<U> versioned) Returns the value of the specified Versioned object if non-null or else returns null.
long	version() Returns the version.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Versioned

public Versioned(V value,
                 long version,
                 long creationTime)

Constructs a new versioned value.

Parameters:

value - value

version - version

creationTime - milliseconds of the creation event from the Java epoch of 1970-01-01T00:00:00Z

Versioned

public Versioned(V value,
                 long version)

Constructs a new versioned value.

Parameters:

value - value

version - version

Method Detail

value

public V value()

Returns the value.

Returns:

value.

version

public long version()

Returns the version.

Returns:

version

creationTime

public long creationTime()

Returns the system time when this version was created.

Care should be taken when relying on creationTime to implement any behavior in a distributed setting. Due to the possibility of clock skew it is likely that even creationTimes of causally related versions can be out or order.

Returns:

creation time

map

public <U> Versioned<U> map(java.util.function.Function<V,U> transformer)

Maps this instance into another after transforming its value while retaining the same version and creationTime.

Type Parameters:

U - value type of the returned instance

Parameters:

transformer - function for mapping the value

Returns:

mapped instance

valueOrElse

public static <U> U valueOrElse(Versioned<U> versioned,
                                U defaultValue)

Returns the value of the specified Versioned object if non-null or else returns a default value.

Type Parameters:

U - type of the versioned value

Parameters:

versioned - versioned object

defaultValue - default value to return if versioned object is null

Returns:

versioned value or default value if versioned object is null

valueOrNull

public static <U> U valueOrNull(Versioned<U> versioned)

Returns the value of the specified Versioned object if non-null or else returns null.

Type Parameters:

U - type of the versioned value

Parameters:

versioned - versioned object

Returns:

versioned value or null if versioned object is null

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object other)

Overrides:

equals in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object