sekaiser/loom-generators

Comparison of different approaches for implementing geneartors in Java using Project Loom.

Implementation of Generators with JDK21

This repositories contains code discussed in an article I wrote. The article can be found here.

What's in it

The package loom.generators.mvysny contains the generator as implemented in mvysny/vaadin-loom. The developer also wrote a nice article explaining how it works.

The package loom.generators.robaho contains the generator as implemented in robaho/generators. He also provides a synchronous version.

The package loom.generators.sk4is3r contains a generator implemented by myself. This generator is based on jdk.internal.vm.Continuation. Later, I figured out that someone else already had this idea and provided a decent implementation of continuations based generators in JDK21. Therefore, I highly recommend that you check out his pedrolamarao/generators-jvm.

Although not explicitly mentioned in my article, the package loom.generators.kelemen contains another custom implementation of a queue based generator. The article does not cover it, because another queue based generator is already discussed and the implementation depends on a couple of custom 3rd party dependencies. Discussing them is out of scope of the article.

Setup

You will need JDK21 to run this project. I recommend using sdkman, e.g. sdk install java 21.ea.31-open

This project uses gradle 8.2.1. You can install gradle via homebrew, e.g. brew install gradle

Build

Just run gradle build.

Note: The loom.generators module requires JDK version 21 with preview features enabled.

Results of performance test

The code is located in loom.generators.perf.

Implementation	avg time
No generator	3.1 ms
loom.generators.robaho	1258.3 ms
loom.generators.mvysny	432.5 ms
loom.generators.sk4is3r	156.7 ms
loom.generators.kelemen	3400.6 ms