List of Classes of arbitrary type

Hi,

How can I create a List of Classes of arbitrary type?
For a List[Class[AnyRef]] the compiler won't allow me to use
List(classOf[String]).

Thanx
Heiko

Heiko Seeberger wrote:
> Hi,
>
> How can I create a List of Classes of arbitrary type?
> For a List[Class[AnyRef]] the compiler won't allow me to use
> List(classOf[String]).
>
> Thanx
> Heiko

In a perfect world, the type parameter of the 'Class' class would have
been declared to be co-variant. E.g.

class Class[+T] ...

However, the world is not perfect and this class was defined in Java,
not Scala. To deal with this, Scala has "existential types". If you
declare your list like in the snippet below it should work:

var classes = List[Class[_ <: Object]]()
classes += classOf[Object]
classes += classOf[String]

Cheers,

Roman

scala> class Foo; class Bar
defined class Foo
defined class Bar

scala> val x : List[Class[_]] = List(classOf[String], classOf[Int], classOf[Foo], classOf[Bar])
x: List[Class[_]] = List(class java.lang.String, int, class Foo, class Bar)


On Tue, Mar 3, 2009 at 12:40 PM, Heiko Seeberger <heiko.reg@seebergers.de> wrote:

Hi,

How can I create a List of Classes of arbitrary type?
For a List[Class[AnyRef]] the compiler won't allow me to use List(classOf[String]).

Thanx
Heiko

List[Class[+AnyRef]] ?

BR,
John

On Tue, Mar 3, 2009 at 9:44 PM, Heiko Seeberger
wrote:
> Hi,
>
> How can I create a List of Classes of arbitrary type?
> For a List[Class[AnyRef]] the compiler won't allow me to use
> List(classOf[String]).
>
> Thanx
> Heiko
>

Try List[Class[_]]

--j

On Tue, Mar 3, 2009 at 12:44 PM, Heiko Seeberger <heiko.seeberger@googlemail.com> wrote:

Hi,

How can I create a List of Classes of arbitrary type?
For a List[Class[AnyRef]] the compiler won't allow me to use List(classOf[String]).

Thanx
Heiko