Package org.hibernate.id.uuid

Class UuidVersion7Strategy

java.lang.Object

org.hibernate.id.uuid.UuidVersion7Strategy

All Implemented Interfaces:

Serializable, UuidValueGenerator, UUIDGenerationStrategy

public class UuidVersion7Strategy
extends Object
implements UUIDGenerationStrategy, UuidValueGenerator

Implements UUID Version 7 generation strategy as defined by the RFC 9562.

• 48 bits - 48-bit big-endian unsigned number of the Unix Epoch timestamp in milliseconds.
• 4 bits - version field, set to 0b0111 (7).
• 12 bits - sub-milliseconds part of timestamp (resolution approximately 1/4 of millisecond) to guarantee additional monotonicity.
• 2 bits - variant field, set to 0b10.
• 14 bits - counter to guarantee additional monotonicity, resets to 0 when timestamp changes.
• 48 bits - pseudorandom data to provide uniqueness.

See Also:

• Serialized Form

API Note:

Version 7 features a time-ordered value field derived from the widely implemented and well-known Unix Epoch timestamp source, the number of milliseconds since midnight 1 Jan 1970 UTC, leap seconds excluded.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	UuidVersion7Strategy.State

Field Summary

Fields

Modifier and Type	Field	Description
static final UuidVersion7Strategy	INSTANCE

Constructor Summary

Constructors

Constructor	Description
UuidVersion7Strategy()
UuidVersion7Strategy(Instant initialTimestamp, int initialSequence)

Method Summary

Modifier and Type	Method	Description
UUID	generateUuid(SharedSessionContractImplementor session)	Generate the UUID value
UUID	generateUUID(SharedSessionContractImplementor session)	Generate the UUID.
int	getGeneratedVersion()	Version 7

Methods inherited from class java.lang.Object

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

Field Details

INSTANCE

public static final UuidVersion7Strategy INSTANCE

Constructor Details

UuidVersion7Strategy

@Internal
public UuidVersion7Strategy()

UuidVersion7Strategy

@Internal
public UuidVersion7Strategy(Instant initialTimestamp,
 int initialSequence)

Method Details

getGeneratedVersion

public int getGeneratedVersion()

Version 7

Specified by:

getGeneratedVersion in interface UUIDGenerationStrategy

Returns:

The supported generation version

generateUUID

public UUID generateUUID(SharedSessionContractImplementor session)

Description copied from interface: UUIDGenerationStrategy

Generate the UUID.

Specified by:

generateUUID in interface UUIDGenerationStrategy

Parameters:

session - The session asking for the generation

Returns:

The generated UUID.

generateUuid

public UUID generateUuid(SharedSessionContractImplementor session)

Description copied from interface: UuidValueGenerator

Generate the UUID value

Specified by:

generateUuid in interface UuidValueGenerator