Obtain Companion object given a Class Manifest

[Raul Raja Martinez]

I have a case where I need the companion object given a class manifest.

Looking through the docs and old stackoverflow questions all solutions and references I've found are previous to 2.10.

Is there a recommended way to do it with the new reflection API's ?

Thanks!

[Flavio W. Brasil]

Example using SMirror:

scala> class Test; object Test { def a = "a" }

defined class Test

defined module Test

scala> implicit val mirror = scala.reflect.runtime.currentMirror

mirror: reflect.runtime.universe.Mirror = JavaMirror with scala.tool…

scala> import net.fwbrasil.smirror._

import net.fwbrasil.smirror._

scala> val clazz = sClassOf[Test]

clazz: net.fwbrasil.smirror.SClass[Test] = Test

scala> clazz.companionObjectOption

res0: Option[net.fwbrasil.smirror.SInstance[Test]] = Some(Test (bound to Test$@2a51b326))

scala> clazz.companionSClassOption

res1: Option[net.fwbrasil.smirror.SCompanionClass[Test]] = Some(Test)

scala> clazz.companionSClassOption.get.methods

res3: List[net.fwbrasil.smirror.SMethod[Test]] = List(a(): java.lang.String)

-- 

Flávio W. Brasil

http://activate-framework.org

{persistence as it should be}

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[Raul Raja Martinez]

Thanks Flávio, I will look into it and use SMirror if I can't find a simpler way. I was hoping for something more lightweight than a library like a straight up class.companion or something built in given companion objects are so common and supported by scala as first class citizens

[Eugene Burmako]

00:04 ~/Projects/210x (2.10.x)$ scala
Welcome to Scala version 2.10.2-20130329-164357-00fcd46ed0 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_43).
Type in expressions to have them evaluated.
Type :help for more information.

scala> class C; object C
defined class C
defined module C

scala> import scala.reflect.runtime.{currentMirror => cm}
import scala.reflect.runtime.{currentMirror=>cm}

scala> cm.classSymbol(classOf[C]).companionSymbol
res0: reflect.runtime.universe.Symbol = object C

[Eugene Burmako]

This will get the instance of the module symbol we got in the previous email:

scala> cm.reflectModule(res0.asModule).instance
res2: Any = C$@5dcde3f3

[Raul Raja Martinez]

Eugene, thanks so much, that worked!