SBT: How to run an annotation processing plugin - scala

Question

Does anyone knows how to configure a SBT project to run an annotation processor (APT)? I'm doing some lab on a web project, using some Java tools like QueryDSL, and i need to generate querydsl classes for my JPA model classes, in a similar way QueryDSL Maven plugin does.
Thanks in advance.

Answer 1

You could manually run the annotation processor (see command below) or implement an SBT task similar to the following:
lazy val processAnnotations = taskKey[Unit]("Process annotations")
processAnnotations := {
val log = streams.value.log
log.info("Processing annotations ...")
val classpath = ((products in Compile).value ++ ((dependencyClasspath in Compile).value.files)) mkString ":"
val destinationDirectory = (classDirectory in Compile).value
val processor = "com.package.PluginProcessor"
val classesToProcess = Seq("com.package.Class1", "com.package.Class2") mkString " "
val command = s"javac -cp $classpath -proc:only -processor $processor -XprintRounds -d $destinationDirectory $classesToProcess"
failIfNonZeroExitStatus(command, "Failed to process annotations.", log)
log.info("Done processing annotations.")
}
def failIfNonZeroExitStatus(command: String, message: => String, log: Logger) {
val result = command !
if (result != 0) {
log.error(message)
sys.error("Failed running command: " + command)
}
}
packageBin in Compile <<= (packageBin in Compile) dependsOn (processAnnotations in Compile)
Update destinationDirectory, processor, and classesToProcess as necessary.
You might also change the "-d" flag to "-s" depending on the type of annotation processor you have (see options for javac).