A Quick Look At Gradle

I'd say up until a month or so ago, I knew about Gradle but I had no real idea what it offered. I knew it was more elaborate than Gant, but that was all.

It's about time I took a closer look at Gradle. The most obvious cool feature is that you can write your build scripts using Groovy. This is sweet. Beyond that, it is probably easiest to list Gradle's own summary, as of this writing:

• A very flexible general purpose build tool like Ant.
• Switchable, build-by-convention frameworks a la Maven, for Java, Groovy and Scala projects. But we never lock you in!
• Groovy build scripts.
• Powerful support for multi-project builds.
• Powerful dependency management (based on Apache Ivy).
• Full support for your existing Maven or Ivy repository infrastructure.
• Support for transitive dependency management without the need for remote repositories and pom.xml or ivy.xml files (optional).
• Ant tasks and builds as first class citizens.

So... dependency management? check. multi project builds? check. Easy to write general purpose scripts? check.

What I think has extremely high potential is the idea of pluggable build frameworks, a la maven support. Use all of the best pieces of tools from one - Gradle. I think they could go a really long way with this, and it will remain a strong contender as I also take a closer look at some of the new Maven 3 features.

Downloading and extracting gradle-0.8-all.zip, one thing is immediately obvious. Comprehensive documentation and examples FOR THE WIN!

I can't even describe how frustrating playing with maven 2 was three years ago. Documentation was hard to understand, and the basic example tutorials just didn't cover my needs. I ended up banging my head a lot, when all I really needed was some good sample poms illustrating all of the tool's features. Gradle provides this out of the box and scores major points for it. I haven't even looked at the website docs in detail yet, but they seem easy to follow.

Some Maven 3.0 Info

I do intend to investigate Gradle, but I can't shake the feeling that Maven 3 will really rock. On that note, about all I have time for tonight is to pull together a few links. Nothing a couple minutes of searching couldn't accomplish, but hopefully it is of value.

Here's a presentation that happened all the way back in April. I'm sure there are more recent ones, so I'll try to update with additional links. There are (not surprisingly) quite a lot of good posts on the Sonatype blog. In particular, there is a series of posts titled "Paving the desire lines". It's very satisfying reading a developer talk about the small finishing touches to a project with real passion. I haven't read the whole post yet (and I spot 2 parts so far), but it has my appetite whet.

Maven 3.0 alphas have been coming out recently, with Alpha 3 coming out last Friday. I just grabbed it tonight (seems to be alpha 4 now) and took it for a quick spin. To test it, I built Hudson/main, which has 4.0.0 POMs.

This merits close following...

UPDATE: Walter linked a more recent video+slide presentation by Jason van Zyl

Java Build Tools

There are a lot of build tools for Java. More than I have seen for any other language I've used. When working with Java, I've used Ant, Maven 1, and Maven 2. I know of at least a few more, and I recently found this post with a link to a poll on what build tools people are using this year (for Java).

If you navigate to the 'What Build Tool are you using in 2009?' poll (I can't post a direct link, sorry, but there are only 3 polls to choose from), you will see quite a selection of tools.

Unfortunately, right now I'm that single Maven 1.x user (along with some Ant). It's tough - things work well enough, but there is no direct path to Maven 2.x for us (oh maven.xml, you looked so helpful, but you've trapped us!). In its defense, this project was using Maven 1 back in 2004. It's not surprising that in 5 years some cruft has accumulated.

I am fed up with having to write build scripts in XML, so even if a Maven 2 migration path was simple, I'm not sure it's desired. Gant would get rid of the XML while keeping familiar territory - but I feel like I need something richer than basic Ant. Gradle looks very promising, and I've been meaning to read up on some of the threads on where Gant and Gradle are going to get a better idea of things, but I haven't yet.

Lo and Behold, while pulling up links for this blog post... I stumbled upon a post about Maven 3.

Support for several build script file formats? YAML, Groovy? Hell yeah! I am going to have to do my research on this one.

I wasn't quite sure where I was going with this post, but I think I'll sample some of the build tools I've mentioned (including early maven 3 builds) and report in on them. If I'm motivated, maybe I will do a 'Hello World' project in each build tool. Gant, Gradle, and Maven 3.