Fauxflake by rholder

What is this?

Fauxflake is an easily embeddable, decentralized, k-ordered unique ID generator. It can use the same encoded ID format as Twitter's Snowflake or Boundary's Flake implementations as well as any other customized encoding without too much effort. The fauxflake-core module has no external dependencies and is meant to be about as light as possible while still delivering useful functionality. Essentially, if you want to be able to generate a unique identifier across your infrastructure with reasonable assurances about collisions, then you might find this useful.

The Problem

You've run into one or more of the following scenarios:

You need to generate a unique identifier, perhaps for an RDBMS primary key or for a NoSQL storage abstraction, and you need it done fast.
You need to be able to guarantee the loose orderings of unique keys when more than one machine is generating them.
A centralized key generation service seems too heavy or is otherwise unacceptable.
You've thought about clock drift, server time running backwards, or any of a number of horrible things you read here that make relying on simple system timestamps for anything absolutely horrifying.

Where can I get it?

You can find this module in the Maven Central repository by using your favorite build tool:

Maven

<dependency>
  <groupId>com.github.rholder.fauxflake</groupId>
  <artifactId>fauxflake-core</artifactId>
  <version>1.1.0</version>
</dependency>

Gradle

compile "com.github.rholder.fauxflake:fauxflake-core:1.1.0"

Quickstart

Let's say you want to generate a lexicographically sortable, Twitter compatible identifier, as a String. You could do that with the following snippet:

    IdGenerator snowflake = IdGenerators.newSnowflakeIdGenerator();
    String id = snowflake.generateId(1000).asString();

The Snowflake and Flake IdGenerator instances are both thread-safe and intended to be used as singletons.

Customization

The MachineIdProvider is meant to be customized when the "good enough" guarantees coming from the MacMachineIdProvider and the MacPidMachineIdProvideraren't really good enough for your use case and you need more strictness in how those are being set. For instance, by just swapping in your own unique machine identifier from a system property, you can get an actual universal guarantee among all of your machines if each are given a unique number on startup:

public class CustomMachineIdProvider implements MachineIdProvider {
    @Override
    public long getMachineId() {
        return Long.valueOf(System.getProperty("my.app.machine.id"));
    }
}

You might want to note that a Snowflake ID only has 1024 possible unique machine identifiers since the specification calls for reserving 10 bits for this information.

Additional Documentation

Javadoc can be found here.

Building from source

The Fauxflake project uses a Gradle-based build system. In the instructions below, ./gradlew is invoked from the root of the source tree and serves as a cross-platform, self-contained bootstrap mechanism for the build. The only prerequisites are Git and JDK 1.6+.

check out sources

git clone git://github.com/rholder/fauxflake.git

compile and test, build all jars

./gradlew build

install all jars into your local Maven cache

./gradlew install

License

The Fauxflake module is released under version 2.0 of the Apache License.

Fauxflake

Fauxflake is an easily embeddable decentralized, k-ordered unique ID generator.