Modularization or Automatic-Module-Name

[io7m]

Hello!

The rome project already appears to be quite modular. Is there any intention to publish full JDK 9 modules? Failing that, is there any chance a new release could be pushed with
Automatic-Module-Name entries in the jar manifests?

[mishako]

Hi Mark! I see that you're helping other teams with jdk9 modules. Very nice! Any chance you can help us too? We are already publishing OSGi bundles (see #216). I guess jdk9 modules are similar? If you're busy it's fine, we can probably figure it out.

[io7m]

Hello. Yes, I can certainly help. As you're already publishing OSGi bundles, you've likely already done the hard work (knowing what packages you need to export, avoiding circular dependencies, etc).

I see from your main parent POM that you're producing JDK 6 bytecode. If you want to go the full modularization route, the least painful way to proceed is to start requiring JDK 9 to build the code. You'll still be only requiring JDK 6 to run the code, but anyone building from source would require JDK 9 to do so. JDK 9 has some nice features that give stronger guarantees about compatibility than previous JDK releases did. For example, if you compile the code with JDK 8, specifying Java 6 bytecode as the output, nothing actually stops you from accidentally using JDK 8 APIs. The new -release flag in JDK 9 enforces API usage too, so it's a compelling reason to move to the new version.

Depending on how you feel about using JDK 9, I can make an initial pass over the codebase to write the initial module descriptors and the required maven-compiler-plugin executions. The main thing that can block the work is if you depend on libraries that haven't yet been modularized (or that haven't published Automatic-Module-Name entries). I've not checked these yet.

[mishako]

Yeah, looks like the libraries we depend on (slf4j and jdom2) don't declare Automatic-Module-Name in their jars. I created a pull-request for our jars (#375), but I'm guessing our dependencies need to be updated too in order for anyone to use Rome in a modular environment.

[io7m]

I don't know about jdom2, but the beta version of the 1.8.0 slf4j API does have the right entries (both logback and log4j appear to be fully modularized right now).

[io7m]

I wrote a small Maven plugin that can give you a reasonable idea as to what needs to be done in order to modularize your projects:

https://github.com/io7m/modulechaser

The results for rome aren't all that enlightening (they're what we've already discussed: slf4j and logback are modularized, jdom2 isn't in any form).

[mishako]

Closing this because Rome has Automatic-Module-Name since version 1.10.0 (pull request #375).