Re: Anonymous class - I don't know how to...

From:

Mark Space <markspace@sbc.global.net>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 28 Jun 2007 21:19:39 GMT

Message-ID:

<LBVgi.18511$RX.8454@newssvr11.news.prodigy.net>

kaja_love160@yahoo.com wrote:

Example:

Object o = new Object() { public int anon = 20; };

The above statement creates an object of anonymous class and returns
a reference to it. But in order to use members declared in anonymous
class ( o.anon ), variable o would have to be of same type as
anonymous class. How do we make 'o' of same type, considering that
anonymous class has no name?

To re-enforce what Andreas said, this is a design issue, not a language
issue. You must design your super-class so that you can access
variables or other information from the anonymous class.

If you absolutely cannot, then here's the reflection example:

package anontest;
import java.lang.reflect.Field;

public class Main
{
     public static void main(String[] args) throws IllegalAccessException
     {
         Object o = new Object() { public int anon = 20; };
         printAnon( o );

     }
     static void printAnon( Object o ) throws IllegalAccessException
     {
         Class c = o.getClass();
         Field fields[] = c.getDeclaredFields();
         for( Field f : fields )
         {
             System.out.println( f.getName() + " = " + f.get( o ) );
         }
     }
}

Better to NOT use Object and just design an appropriate super-class however.