256 lines
6.8 KiB
Markdown
256 lines
6.8 KiB
Markdown
|
|
ULID Creator
|
|
======================================================
|
|
|
|
This is a Java implementation of [Universally Unique Lexicographically Sortable Identifier](https://github.com/ulid/spec).
|
|
|
|
In summary:
|
|
|
|
* Sorted by generation time;
|
|
* Can be stored as a UUID/GUID;
|
|
* Can be stored as a string of 26 chars;
|
|
* Can be stored as an array of 16 bytes;
|
|
* String format is encoded to [Crockford's base32](https://www.crockford.com/base32.html);
|
|
* String format is URL safe, is case insensitive, and has no hyphens.
|
|
|
|
This library contains a good amount of [unit tests](https://github.com/f4b6a3/ulid-creator/tree/master/src/test/java/com/github/f4b6a3/ulid). It also has a [micro benchmark](https://github.com/f4b6a3/ulid-creator/tree/master/benchmark) for you to check if the performance is good enough.
|
|
|
|
How to Use
|
|
------------------------------------------------------
|
|
|
|
Create a ULID:
|
|
|
|
```java
|
|
Ulid ulid = UlidCreator.getUlid();
|
|
```
|
|
|
|
Create a Monotonic ULID:
|
|
|
|
```java
|
|
Ulid ulid = UlidCreator.getMonotonicUlid();
|
|
```
|
|
|
|
### Maven dependency
|
|
|
|
Add these lines to your `pom.xml`.
|
|
|
|
```xml
|
|
<!-- https://search.maven.org/artifact/com.github.f4b6a3/ulid-creator -->
|
|
<dependency>
|
|
<groupId>com.github.f4b6a3</groupId>
|
|
<artifactId>ulid-creator</artifactId>
|
|
<version>4.1.2</version>
|
|
</dependency>
|
|
```
|
|
See more options in [maven.org](https://search.maven.org/artifact/com.github.f4b6a3/ulid-creator).
|
|
|
|
### Modularity
|
|
|
|
Module and bundle names are the same as the root package name.
|
|
|
|
- JPMS module name: `com.github.f4b6a3.ulid`
|
|
- OSGi symbolic name: `com.github.f4b6a3.ulid`
|
|
|
|
### ULID
|
|
|
|
The ULID is a 128 bit long identifier. The first 48 bits represent the number of milliseconds since Unix Epoch, 1970-01-01. The remaining 80 bits are generated by a secure random number generator. Its canonical string representation is 26 characters long.
|
|
|
|
```java
|
|
// Generate a ULID
|
|
Ulid ulid = UlidCreator.getUlid();
|
|
```
|
|
|
|
Sequence of ULIDs:
|
|
|
|
```text
|
|
01EX8Y21KBH49ZZCA7KSKH6X1C
|
|
01EX8Y21KBJTFK0JV5J20QPQNR
|
|
01EX8Y21KBG2CS1V6WQCTVM7K6
|
|
01EX8Y21KB8HPZNBP3PTW7HVEY
|
|
01EX8Y21KB3HZV38VAPTPAG1TY
|
|
01EX8Y21KB9FTEJHPAGAKYG9Z8
|
|
01EX8Y21KBQGKGH2SVPQAYEFFC
|
|
01EX8Y21KBY17J9WR9KQR8SE7H
|
|
01EX8Y21KCVHYSJGVK4HBXDMR9 < millisecond changed
|
|
01EX8Y21KC668W3PEDEAGDHMVG
|
|
01EX8Y21KC53D2S5ADQ2EST327
|
|
01EX8Y21KCPQ3TENMTY1S7HV56
|
|
01EX8Y21KC3755QF9STQEV05EB
|
|
01EX8Y21KC5ZSHK908GMDK69WE
|
|
01EX8Y21KCSGJS8S1FVS06B3SX
|
|
01EX8Y21KC6ZBWQ0JBV337R1CN
|
|
^ look
|
|
|
|
|---------|--------------|
|
|
time random
|
|
```
|
|
|
|
### Monotonic ULID
|
|
|
|
The Monotonic ULID is variant of ULID. The random component is incremented by 1 whenever the current millisecond is equal to the previous one. Its main advantage is *speed*.
|
|
|
|
```java
|
|
// Generate a Monotonic ULID
|
|
Ulid ulid = UlidCreator.getMonotonicUlid();
|
|
```
|
|
|
|
Sequence of Monotonic ULIDs:
|
|
|
|
```text
|
|
01EX8Y7M8MDVX3M3EQG69EEMJW
|
|
01EX8Y7M8MDVX3M3EQG69EEMJX
|
|
01EX8Y7M8MDVX3M3EQG69EEMJY
|
|
01EX8Y7M8MDVX3M3EQG69EEMJZ
|
|
01EX8Y7M8MDVX3M3EQG69EEMK0
|
|
01EX8Y7M8MDVX3M3EQG69EEMK1
|
|
01EX8Y7M8MDVX3M3EQG69EEMK2
|
|
01EX8Y7M8MDVX3M3EQG69EEMK3
|
|
01EX8Y7M8N1G30CYF2PJR23J2J < millisecond changed
|
|
01EX8Y7M8N1G30CYF2PJR23J2K
|
|
01EX8Y7M8N1G30CYF2PJR23J2M
|
|
01EX8Y7M8N1G30CYF2PJR23J2N
|
|
01EX8Y7M8N1G30CYF2PJR23J2P
|
|
01EX8Y7M8N1G30CYF2PJR23J2Q
|
|
01EX8Y7M8N1G30CYF2PJR23J2R
|
|
01EX8Y7M8N1G30CYF2PJR23J2S
|
|
^ look ^ look
|
|
|
|
|---------|--------------|
|
|
time random
|
|
```
|
|
|
|
### More Examples
|
|
|
|
Create a ULID from a canonical string (26 chars):
|
|
|
|
```java
|
|
Ulid ulid = Ulid.from("0123456789ABCDEFGHJKMNPQRS");
|
|
```
|
|
|
|
---
|
|
|
|
Convert a ULID into a canonical string in lower case:
|
|
|
|
```java
|
|
String string = ulid.toLowerCase(); // 0123456789abcdefghjkmnpqrs
|
|
```
|
|
|
|
---
|
|
|
|
Convert a ULID into a UUID:
|
|
|
|
```java
|
|
UUID uuid = ulid.toUuid(); // 0110c853-1d09-52d8-d73e-1194e95b5f19
|
|
```
|
|
|
|
---
|
|
|
|
Convert a ULID into a [RFC-4122](https://tools.ietf.org/html/rfc4122) UUID v4:
|
|
|
|
```java
|
|
UUID uuid = ulid.toRfc4122().toUuid(); // 0110c853-1d09-42d8-973e-1194e95b5f19
|
|
// ^ UUID v4
|
|
```
|
|
|
|
---
|
|
|
|
Get the creation instant of a ULID:
|
|
|
|
```java
|
|
Instant instant = ulid.getInstant(); // 2007-02-16T02:13:14.633Z
|
|
```
|
|
|
|
```java
|
|
// static method
|
|
Instant instant = Ulid.getInstant("0123456789ABCDEFGHJKMNPQRS"); // 2007-02-16T02:13:14.633Z
|
|
```
|
|
|
|
---
|
|
|
|
A key generator that makes substitution easy if necessary:
|
|
|
|
```java
|
|
package com.example;
|
|
|
|
import com.github.f4b6a3.ulid.UlidCreator;
|
|
|
|
public class KeyGenerator {
|
|
public static String next() {
|
|
return UlidCreator.getUlid().toString();
|
|
}
|
|
}
|
|
```
|
|
```java
|
|
String key = KeyGenerator.next();
|
|
```
|
|
|
|
---
|
|
|
|
A `UlidFactory` with `java.util.Random`:
|
|
|
|
```java
|
|
// use a `java.util.Random` instance for fast generation
|
|
UlidFactory factory = UlidFactory.newInstance(new Random());
|
|
Ulid ulid = factory.create();
|
|
|
|
// use the factory
|
|
```
|
|
|
|
---
|
|
|
|
A `UlidFactory` with `ThreadLocalRandom` inside of a `Supplier<byte[]>`:
|
|
|
|
```java
|
|
// use a random supplier that returns an array of 10 bytes
|
|
UlidFactory factory = UlidFactory.newInstance(() -> {
|
|
final byte[] bytes = new byte[Ulid.RANDOM_BYTES];
|
|
ThreadLocalRandom.current().nextBytes(bytes);
|
|
return bytes;
|
|
});
|
|
|
|
// use the factory
|
|
Ulid ulid = factory.create();
|
|
```
|
|
|
|
---
|
|
|
|
Benchmark
|
|
------------------------------------------------------
|
|
|
|
This section shows benchmarks comparing `UlidCreator` to `java.util.UUID`.
|
|
|
|
```
|
|
--------------------------------------------------------------------------------
|
|
THROUGHPUT (operations/msec) Mode Cnt Score Error Units
|
|
--------------------------------------------------------------------------------
|
|
UUID_randomUUID thrpt 5 2060,570 ± 37,242 ops/ms
|
|
UUID_randomUUID_toString thrpt 5 1177,386 ± 39,803 ops/ms
|
|
- - - - - - - - - - - - - - - - - - - - - - - - - - -
|
|
UlidCreator_getUlid thrpt 5 2740,609 ± 86,350 ops/ms
|
|
UlidCreator_getUlid_toString thrpt 5 2526,284 ± 56,726 ops/ms
|
|
- - - - - - - - - - - - - - - - - - - - - - - - - - -
|
|
UlidCreator_getMonotonicUlid thrpt 5 19373,150 ± 192,402 ops/ms
|
|
UlidCreator_getMonotonicUlid_toString thrpt 5 13269,201 ± 254,953 ops/ms
|
|
--------------------------------------------------------------------------------
|
|
Total time: 00:08:01
|
|
--------------------------------------------------------------------------------
|
|
```
|
|
|
|
System: JVM 8, Ubuntu 20.04, CPU i5-3330, 8G RAM.
|
|
|
|
To execute the benchmark, run `./benchmark/run.sh`.
|
|
|
|
Other identifier generators
|
|
-------------------------------------------
|
|
|
|
Check out the other ID generators from the same family:
|
|
|
|
* [UUID Creator](https://github.com/f4b6a3/uuid-creator): Universally Unique Identifiers
|
|
* [TSID Creator](https://github.com/f4b6a3/tsid-creator): Time Sortable Identifiers
|
|
* [KSUID Creator](https://github.com/f4b6a3/ksuid-creator): K-Sortable Globally Unique Identifiers
|
|
|
|
License
|
|
------------------------------------------------------
|
|
|
|
This library is Open Source software released under the [MIT license](https://opensource.org/licenses/MIT).
|