Scala classOf for type parameter

Question

I am trying to create a generic method for object updates using scala / java but I can't get the class for a type parameter.

Here is my code:

object WorkUnitController extends Controller {       def updateObject[T](toUpdate: T, body: JsonObject){   val source = gson.fromJson(body, classOf[T]);   ...  } } 

The error i get is

class type required but T found

I know in java you can't do it but is this possible in scala at all?

Thanks!

Answer 1

Due Manifest is deprecated (Since Scala 2.10.0) this is the updated answer -

import scala.reflect.ClassTag import scala.reflect._  object WorkUnitController extends Controller {   def updateObject[T: ClassTag](toUpdate: T, body: JsonObject){     val source = gson.fromJson(body, classTag[T].runtimeClass)     ???   } } 

You should use ClassTag instead of ClassManifest and .runtimeClass instead of .erasure

Original answer - Yes, you can do that using manifests:

object WorkUnitController extends Controller {       def updateObject[T: ClassManifest](toUpdate: T, body: JsonObject){   val source = gson.fromJson(body, classManifest[T].erasure);   ...  } } 

Answer 2

Vasil's and Maxim's answer helped me.

Personally, I prefer the syntax where implicit is used for adding such parameters (the presented : ClassTag is shorthand for it. So here, in case someone else also sees this to be a better way:

import scala.reflect.ClassTag  object WorkUnitController extends Controller {   def updateObject[T](toUpdate: T, body: JsonObject)(implicit tag: ClassTag[T]){     val source = gson.fromJson(body, tag.runtimeClass)     ???   } } 

Disclaimer: I did not compile the above, but my own similar code works this way.