Documentation for mill-aspectj, a mill plugin to support the AspectJ language and compiler.

Mill version 0.9.3 or newer is required. Using the latest stable Mill release is recommended.

Your module needs to extend de.tobiasroeser.mill.aspectj.AspectjModule which itself extends mill.scalalib.JavaModule.

The module trait de.tobiasroeser.mill.aspectj.AspectjModule has the following configuration options (over those from mill.scalalib.JavaModule).

def aspectjVersion: T[String]

The AspectJ version. Required. For a list of available releases refer to the AspectJ Download Page.

def ivyDeps: T[Agg[Dep]]

The compile and runtime dependencies. Contains by default the aspectjrt.jar which is resolved via ivy (ivy"org.aspectj:aspectjrt:${aspectjVersion()}"). If you do do not use super.ivyDeps() when overriding this def, you need to provide the aspectjrt.jar manually.

def aspectjToolsDeps: T[Agg[Dep]]

The ivy dependencies representing the aspectj compiler classes, which is typically a aspectjtools.jar. Default to ivy"org.aspectj:aspectjtools:${aspectjVersion()}".

def aspectjToolsClasspath: T[Agg[PathRef]]

The aspectj compiler classpath. By default resolved from aspectjToolsDeps.

def ajcOptions: T[Seq[String]]

Additional options to be used by ajc in the compile target.

def aspectPath: T[Agg[PathRef]]

Additional classes, JARs or ZIPs to be used as aspect path (ajc -aspectpath). In most cases it is enough to use aspectModuleDeps and aspectIvyDeps.

def aspectModuleDeps: Seq[JavaModule]

List of modules to be used as aspect path (ajc -aspectpath).

def aspectIvyDeps: T[Agg[Dep]]

List of ivy dependencies to be used as aspect path (ajc -aspectpath).

def effectiveAspectPath: T[Seq[PathRef]]

Effective aspect path (ajc -inpath). In most cases, it is enough to use aspectModuleDeps and aspectIvyDeps.

def weavePath: T[Seq[PathRef]]

List of directories with .class files to weave (into target directory). Corresponds to ajc -inpath option.

def compile: T[CompilationResult]

Compiles the source code with the ajc compiler.

def ajcHelp: Command[Unit]

Shows the help of the AspectJ compiler (ajc -help).

If you override the def aspectjCompileMode to return CompileMode.OnlyAjSources, you can chain the AspectJ compiler after another compiler.

In this setup, the AspectJ compiler will not compile your Java source files but weave-compiles the already compiled classes. Only the *.aj files (if any) are fed as source files. All other inputs (the already compiled classes) are fed via the -inpath option.

With this setup, we can even compile-time weave Scala (and probably also Kotlin or other JVM language) classes. But this only works reliably with Mill 0.10.0 and newer.

The following table shows a matrix of compatible mill and mill-aspectj versions.

To ensure some basic compatibility, there are some integration tests in place. Newer mill versions may work as well.

If you need support for other versions, please create an issue.

You can download binary releases from Maven Central.

Please make sure to use the correct mill platform suffix matching your used mill version.

This project is published under the Apache License, Version 2.0.

Thanks to iba Consulting Gesellschaft mbH & Co KG for the initial development support.

Mill

Mill is a Scala-based open source build tool. In my opinion the best build tool for the JVM. It is fast, reliable and easy to understand.

Me

I am Tobias Roeser, a professional software developer and love to create open source software. I’m actively developing and maintaining Mill as well as several mill plugins.

If you like my work, please star it on GitHub. You can also support me via GitHub Sponsors.

Contributing

If you found a bug or have a feature request, please open a new issue on GitHub. I also accept pull requests on GitHub.

You can also ask question and join our discussion at the GitHub Discussions board