A tiny library for generating UUIDs in automated tests for Java and Kotlin

Table of contents:

• Install
• Examples
  • Java
  • Kotlin
• Why toUUID?
• How toUUID works
  • ⚠️ Never use toUUID in production code ⚠️
• Demo projects
• How to build
• Contact

Install

Maven

<dependency>
    <groupId>io.github.atomfinger</groupId>
    <artifactId>atomfinger-touuid</artifactId>
    <version>1.0.1</version>
    <scope>test</scope>
</dependency>

Gradle

(Using the Maven Central Repository)

testCompile group: 'io.github.atomfinger', name: 'atomfinger-touuid', version: '1.0.1'

Examples

Java

toUUID is first and foremost a Kotlin project. Still, one of the goals was to keep it free for any unnecessary dependencies, which is why Java users should use the UUIDs class to avoid having to deal with any extra dependencies.

UUID from a single integer:

import static io.github.atomfinger.touuid.UUIDs.*;

UUID uuid = toUUID(1);
System.out.println(uuid.toString());
//Output:
//00000000-0000-0000-0000-000000000001

UUID from a list of integers:

import static io.github.atomfinger.touuid.UUIDs.*;

List<UUID> uuids = toUUIDs(Arrays.asList(1, 2, 3, 4, 5));
uuids.forEach((it) -> System.out.println(it.toString()));
//Output:
//00000000-0000-0000-0000-000000000001
//00000000-0000-0000-0000-000000000002
//00000000-0000-0000-0000-000000000003
//00000000-0000-0000-0000-000000000004
//00000000-0000-0000-0000-000000000005

UUID from varargs:

import static io.github.atomfinger.touuid.UUIDs.*;

List<UUID> uuids = toUUIDs(1, 2, 3, 4, 5);
uuids.forEach((it) -> System.out.println(it.toString()));
//Output:
//00000000-0000-0000-0000-000000000001
//00000000-0000-0000-0000-000000000002
//00000000-0000-0000-0000-000000000003
//00000000-0000-0000-0000-000000000004
//00000000-0000-0000-0000-000000000005

UUID from range of integers:

import static io.github.atomfinger.touuid.UUIDs.*;

List<UUID> uuids = toUUIDsFromRange(1, 5);
uuids.forEach((it) -> System.out.println(it.toString()));
//Output:
//00000000-0000-0000-0000-000000000001
//00000000-0000-0000-0000-000000000002
//00000000-0000-0000-0000-000000000003
//00000000-0000-0000-0000-000000000004
//00000000-0000-0000-0000-000000000005

Kotlin

Kotlin has access to all the feature Java has, but also has the addition of extension functions.

Generate based on an integer:

val uuid = 1.toUuid()
println(uuid.toString())
//Output:
//00000000-0000-0000-0000-000000000001

Generate from a list of integers:

val uuids = listOf(1, 2, 3, 4, 5).toUuids()
uuids.forEach { println(it.toString()) }
//Output:
//00000000-0000-0000-0000-000000000001
//00000000-0000-0000-0000-000000000002
//00000000-0000-0000-0000-000000000003
//00000000-0000-0000-0000-000000000004
//00000000-0000-0000-0000-000000000005

Generate based on a range of integers:

val uuids = (1..5).toUuids()
uuids.forEach { println(it.toString()) }
//Output:
//00000000-0000-0000-0000-000000000001
//00000000-0000-0000-0000-000000000002
//00000000-0000-0000-0000-000000000003
//00000000-0000-0000-0000-000000000004
//00000000-0000-0000-0000-000000000005

Generate based on a sequence of integers:

val uuids = uuids().take(5)
uuids.forEach { println(it.toString()) }
//Output:
//00000000-0000-0000-0000-000000000001
//00000000-0000-0000-0000-000000000002
//00000000-0000-0000-0000-000000000003
//00000000-0000-0000-0000-000000000004
//00000000-0000-0000-0000-000000000005

Why toUUID?

Check out the writeup on why toUUID() is worth it

How toUUID works

toUUID takes the integer and puts it at the back of the UUID. Which is why the number:
1
turns into the UUID:
00000000-0000-0000-0000-000000000001.

Here's some more examples:

⚠️ Never use toUUID in production code ⚠️

toUUID is not a replacement for how one normally generates UUIDs in production code. There are a few versions of UUID which all have different algorithms attached to them, and this library bypasses all that. While toUUID generates technically valid UUIDs it does not create a UUID which is suitable for production (even if a random number is passed).

toUUID is to be used in automated testing or to generate a repeatable set of human-readable UUIDs.

Demo projects

Both Kotlin and Java has demo projects:

• Kotlin demo project
• Java demo project

How to build

.toUUID is a standard Maven application:

1. Clone project
2. Run mvn clean install in the project folder

Requirements:

• Java 1.8 or higher
• the Kotlin compiler

Contact

you can contact me through my website or the social links found on said website. Don't hesitate to ask if there are any questions :)