Can you get a class name as a constant for scala annotations?

Question

I have an annotation which requires a String describing a class name, eg com.package.MyClass.

I can pass it as a string but would like it to reference the class itself for compilation/refactoring.

However I cannot use MyClass.getName. or classOf[MyClass].toString because it is not a constant:

Compilation error[annotation argument needs to be a constant

Is there a way to get a const reference to a classes name? Or another way to reference the class names as a string in annotations?

Answer 1

You can't use classOf because it runs on runtime and Java annotations requires constants as arguments. Instead, you could capture the name of your class during compile time using macros.

I would recommend you to use some library which can do that, for example NameOf.

Add dependency on your build.sbt:

libraryDependencies += "com.github.dwickern" %% "scala-nameof" % "1.0.3" % "provided"

Then you can use it like:

import com.github.dwickern.macros.NameOf._

@ApiImplicitParams(Array[ApiImplicitParam](
   new ApiImplicitParam(
     name="Something",
     dataType= qualifiedNameOfType[com.package.MyClass])
   )
)