Re: [OT - sort of] Primitives hurt!

[Huw Evans <hu...@dcs.gla.ac.uk>]

> The nice thing about the Type class is that I can hand it a "Class" 
> object and get back the appropriate type.
>[snip]
> which works great for regular Classes, unfortunately it doesn't work for 
>   primitive types. Calls like:
> 
> *
> Class.forName("int")
>[snip]
> int.class.toString() returns "int"
> int.getClass().getName() returns "int"
> *
> 
> but
> 
> *
> Class.forName("int").toString()
> *
> 
> fails with a ClassNotFoundException.
> 
> This is something that sucks about primitive type names in the Java API. 

When you want to refer to the primitive type int as a class, use:

  Integer.TYPE

the TYPE field is of type Class and is defined on all the primitive type 
wrappers.  For example:

public class A {
  public static void main(String[] argv) throws Exception {
    System.out.println(int.class);
    System.out.println(Integer.TYPE);
  }
}

both of these print "int".  In fact, the int.class is substituted by my 
compiler (javac 1.4.1 on a solaris 5.7 machine) in to the Integer.TYPE call.

So, you need to check the need to do something with the primitive type, and 
instead of call Class.forName(<primitive type name>), you need to call the 
appropriate wrapper.TYPE.

This is a pain, I agree, and it is a little sucky, I agree.  However, it does 
do the job :)  Don't get me started on the use of primitives in Java, it's one 
of my favourite rants about the language :)
Huw



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Re: [OT - sort of] Primitives hurt!

["Mark R. Diggory" <md...@latte.harvard.edu>]

Huw Evans wrote:

> So, you need to check the need to do something with the primitive type, and 
> instead of call Class.forName(<primitive type name>), you need to call the 
> appropriate wrapper.TYPE.
> 

Thank you for the tip, I didn't realize that was available in the 
wrapper classes too. I do end up having to create a map of some sort to 
get from the string representation to the actual class still. Jouzas' 
code captures this issue (thank you!).

> This is a pain, I agree, and it is a little sucky, I agree.  However, it does 
> do the job :)  Don't get me started on the use of primitives in Java, it's one 
> of my favourite rants about the language :)
> Huw
> 

It's just amazing to me, I bet this one little issue with 
Class.classForName(...) and primitives probibly creates "hundreds of 
thousands" of extra lines of replicated javacode spanning many Java 
Development Projects the world over.

-Mark


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