Module io.ebean.core

Package io.ebeaninternal.server.idgen

Class UuidV1RndIdGenerator

java.lang.Object

io.ebeaninternal.server.idgen.UuidV1RndIdGenerator

All Implemented Interfaces:

PlatformIdGenerator

Direct Known Subclasses:

UuidV1IdGenerator

public class UuidV1RndIdGenerator
extends Object
implements PlatformIdGenerator

IdGenerator for (pseudo) type 1 UUIDs.

This implementation generates a type 1 UUID according to https://tools.ietf.org/html/rfc4122.html#section-4.2 but has no persistence storage. It generates a new random 47 bit node ID with every UUID.

Use this, if you want randomness in your UUIDs but want to take advantage of index optimizations of the database. It may be good with AUTO_BINARY_OPTIMIZED and MySql.

See: https://www.percona.com/blog/2014/12/19/store-uuid-optimized-way/

Field Summary

Fields

Modifier and Type	Field	Description
protected final AtomicInteger	clockSeq
static final UuidV1RndIdGenerator	INSTANCE
protected static final System.Logger	log
protected static final long	MILLIS_TO_UUID
protected final AtomicLong	timeStamp
protected static final long	UUID_EPOCH_OFFSET

Fields inherited from interface io.ebean.config.dbplatform.PlatformIdGenerator

AUTO_UUID

Constructor Summary

Constructors

Constructor	Description
UuidV1RndIdGenerator()

Method Summary

Modifier and Type	Method	Description
protected void	computeNanoOffset()	Computes the internal offset between System.nanoTime() and System.currentTimeMillis().
String	getName()	Returns "uuid".
protected byte[]	getNodeIdBytes()	returns a random 47 bit value according to https://tools.ietf.org/html/rfc4122.html#section-4.5
boolean	isDbSequence()	Returns false.
UUID	nextId(Transaction t)	Return UUID from UUID.randomUUID();
void	preAllocateIds(int allocateSize)	Ignored for UUID as not required as a performance optimisation.
protected void	saveState()	Method to overwrite to save the state in a non volatile place.

Methods inherited from class java.lang.Object

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

Field Details

log

protected static final System.Logger log

UUID_EPOCH_OFFSET

protected static final long UUID_EPOCH_OFFSET

See Also:

• Constant Field Values

MILLIS_TO_UUID

protected static final long MILLIS_TO_UUID

See Also:

• Constant Field Values

INSTANCE

public static final UuidV1RndIdGenerator INSTANCE

clockSeq

protected final AtomicInteger clockSeq

timeStamp

protected final AtomicLong timeStamp

Constructor Details

UuidV1RndIdGenerator

public UuidV1RndIdGenerator()

Method Details

computeNanoOffset

protected void computeNanoOffset()

Computes the internal offset between System.nanoTime() and System.currentTimeMillis().

saveState

protected void saveState()

Method to overwrite to save the state in a non volatile place.

getNodeIdBytes

protected byte[] getNodeIdBytes()

returns a random 47 bit value according to https://tools.ietf.org/html/rfc4122.html#section-4.5

nextId

public UUID nextId(Transaction t)

Return UUID from UUID.randomUUID();

Specified by:

nextId in interface PlatformIdGenerator

getName

public String getName()

Returns "uuid".

Specified by:

getName in interface PlatformIdGenerator

isDbSequence

public boolean isDbSequence()

Returns false.

Specified by:

isDbSequence in interface PlatformIdGenerator

preAllocateIds

public void preAllocateIds(int allocateSize)

Ignored for UUID as not required as a performance optimisation.

Specified by:

preAllocateIds in interface PlatformIdGenerator