Compiler argument provider example

build.gradle

plugins {
    id 'java'
}

tasks.withType(JavaCompile).configureEach {
    def resourcesDir = project.file("${projectDir}/resources")
    options.compilerArgumentProviders.add(MyAnnotationArgumentProvider.from(resourcesDir))

    // This captures the argument provider as a custom value in the build scan for troubleshooting purposes only
    doFirst {
        buildScan.value "${path} compiler args", options.allCompilerArgs.join("\n")
    }
}

class MyAnnotationArgumentProvider implements CommandLineArgumentProvider {
    @InputDirectory
    @PathSensitive(PathSensitivity.RELATIVE)
    File inputDir

    MyAnnotationArgumentProvider(File inputDir) {
        this.inputDir = inputDir
    }

    static MyAnnotationArgumentProvider from(File inputDir) {
        return new MyAnnotationArgumentProvider(inputDir)
    }

    Iterable<String> asArguments() {
        return ["-Aresources.dir=${inputDir}"]
    }
}