How the get the classOf for a scala object type

Question

I wonder how to get a class object for an object type in Scala. Ok, that is a mouth full because of the double meaning for object. So here an example which will fail:

object Main
{
   private [this] val TAG = classOf [Main].getName;
} // Main

If Main was class it works perfectly. Any ideas?

Radices

Answer 1

scala> Main.getClass
res1: java.lang.Class[_] = class Main$

Drogue

Yes. I see, now it becomes all clear. objects have exactly one instance and therefore you call getClass. Thanks. – Radices

@Radices Actually, I'd say that's incorrect. objects don't have instances at all, because they aren't types; they are the only instances of (compiler-generated) classes, and that's why you can call getClass. – Drogue

Is their a Way to do this as a compile time Constant so that it can be used for a Java Annotation Attribute of type Class ? – Cerussite

@MarkusKnecht I don't know one; you may want to ask this as a separate question. – Drogue

Answer 2

The reason why classOf[Main] doesn't work is because Main is not a type.

Classes and traits define types, objects do not.

Squelch

Answer 3

Since Main is an object, for your example to work, simply replace your assignment line with;

private [this] val TAG = this.getClass.getName;

Szczecin

Answer 4

It is possible to refer an object type. e.g:

classOf[Main.type]

Clomp