com.github.f4b6a3.uuid.factory

Class LexicalOrderGuidCreator

java.lang.Object

com.github.f4b6a3.uuid.factory.abst.AbstractUuidCreator

com.github.f4b6a3.uuid.factory.LexicalOrderGuidCreator

All Implemented Interfaces:

NoArgumentsUuidCreator

public class LexicalOrderGuidCreator
extends AbstractUuidCreator
implements NoArgumentsUuidCreator

Factory that creates lexicographically sortable GUIDs, based on the ULID specification - Universally Unique Lexicographically Sortable Identifier. ULID specification: https://github.com/ulid/spec

Field Summary

Fields

Modifier and Type	Field and Description
protected static String	OVERFLOW_MESSAGE
protected TimestampStrategy	timestampStrategy

Fields inherited from class com.github.f4b6a3.uuid.factory.abst.AbstractUuidCreator

NIL_UUID, RFC4122_VARIANT_BITS, RFC4122_VERSION_BITS, version

Constructor Summary

Constructors

Constructor and Description
LexicalOrderGuidCreator()

Method Summary

Modifier and Type	Method and Description
UUID	create() Return a Lexical Order GUID.
protected void	increment() Increment the random part of the GUID.
protected void	reset() Reset the random part of the GUID.
<T extends LexicalOrderGuidCreator> T	withTimestampStrategy(TimestampStrategy timestampStrategy) Used for changing the timestamp strategy.

Methods inherited from class com.github.f4b6a3.uuid.factory.abst.AbstractUuidCreator

getVariantBits, getVersion, getVersionBits, setVariantBits, setVersionBits, valid

Methods inherited from class java.lang.Object

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

Field Detail

OVERFLOW_MESSAGE

protected static final String OVERFLOW_MESSAGE

See Also:

Constant Field Values

timestampStrategy

protected TimestampStrategy timestampStrategy

Constructor Detail

LexicalOrderGuidCreator

public LexicalOrderGuidCreator()

Method Detail

create

public UUID create()

Return a Lexical Order GUID. It has two parts: 1. A part of 48 bits that represent the amount of milliseconds since Unix Epoch, 1 January 1970. 2. A part of 80 bits that has a random value generated a secure random generator. If more than one GUID is generated within the same millisecond, the random part is incremented by one. The random part is reset to a new value every time the millisecond part changes. ### Specification of Universally Unique Lexicographically Sortable ID #### Components ##### Timestamp It is a 48 bit integer. UNIX-time in milliseconds. Won't run out of space 'til the year 10889 AD. ##### Randomness It is a 80 bits integer. Cryptographically secure source of randomness, if possible. #### Sorting The left-most character must be sorted first, and the right-most character sorted last (lexical order). The default ASCII character set must be used. Within the same millisecond, sort order is not guaranteed. #### Monotonicity When generating a ULID within the same millisecond, we can provide some guarantees regarding sort order. Namely, if the same millisecond is detected, the random component is incremented by 1 bit in the least significant bit position (with carrying). If, in the extremely unlikely event that, you manage to generate more than 280 ULIDs within the same millisecond, or cause the random component to overflow with less, the generation will fail.

Specified by:

create in interface NoArgumentsUuidCreator

Returns:

UUID a UUID value

Throws:

UuidCreatorException - an overflow exception if too many requests within the same millisecond causes an overflow when incrementing the random bits of the GUID.

reset

protected void reset()

Reset the random part of the GUID.

increment

protected void increment()

Increment the random part of the GUID.

Throws:

UuidCreatorException - if an overflow happens.

withTimestampStrategy

public <T extends LexicalOrderGuidCreator> T withTimestampStrategy(TimestampStrategy timestampStrategy)

Used for changing the timestamp strategy.

Parameters:

timestampStrategy - a timestamp strategy

Returns:

LexicalOrderGuidCreator