Re: Obtaining class instance of generic quantified type

From:

Owen Jacobson <angrybaldguy@gmail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 24 Apr 2008 10:07:31 -0700 (PDT)

Message-ID:

<c8de8d4f-6dd0-4821-9ce8-9bf8ed279d66@56g2000hsm.googlegroups.com>

On Apr 24, 12:13 pm, Rakesh <rakesh.use...@gmail.com> wrote:

Hi -
   For a particular method with a signature like this -

    class GlobalClass {

       public abstract <R> R process(Object obj_, Class<R>
returnType_);

   }

  I wanted to quantify it with NodeList<Node> .(substitute R with
NodeList<Node> ).

  So I tried this one ..

   GlobalClass global = ...
   Object obj =

   NodeList<Node> list = global.process(obj, NodeList.class=

);

That code resulted in warnings.
Doing something like -

NodeList<Node> list = global.proces(obj,
NodeList.class<Node.class> );

results in a compilation error.

What is the correct way of doing this.

There is no object reprepsenting the class NodeList<Node> - only an
object representing the class NodeList. This is one of the many holes
in generics as a consequence of erasure. By the same token, you
cannot reflectively create a NodeList<T> for any T - you can only
create instances of the raw type, NodeList.

In short, you can't get there from here without even more code,
without ignoring Java's type safety rules somewhere.