Numeric method parameters & reflection

Question

Hi everyone,
I have a rather interesting problem for you...
I'm writing a program that will allow a user to call bean methods declaratively (i.e. in an XML doc) for any arbitrary bean. My problem is determining how to treat numeric parameter values. If a user wants to call doSomething(5), how do I know what Class type I need to pass in so that 5 matches the formal parameter type of the method being called? The actual parameter could be considered a byte, int, long, float or double.
Here's an example:
import java.lang.reflect.*;
public class ReflectTest
   public ReflectTest()
      try
         Class[] typeList = new Class[1];
         Object[] paramList = new Object[1];
         typeList[0] = Integer.TYPE;
         paramList[0] = new Integer(6);
         Method method = getClass().getMethod("doSomething",typeList);
         Object ret = method.invoke(this,paramList);
         System.out.println(ret.toString());
       catch(Exception ex)
         ex.printStackTrace();
   public String doSomething(int x)
      return "x="+x;
   public static void main(String[] args)
      ReflectTest reflectTest = new ReflectTest();
}This example works. But let's suppose the method signature was doSomething(long x). The getMethod() call would fail, because I had passed it a parameter of Integer.TYPE, and not Long.TYPE. Ironically, you could leave the call to invoke() as-is, it handles the widening automatically. Any ideas on how to go about this??
Thanks!

Answer 1

I'm writing a program that will allow a user tocall
bean methods declaratively (i.e. in an XML doc) for
any arbitrary bean. My problem is determining howto
treat numeric parameter values. If a user wants to
call doSomething(5), how do I know what Class typeI
need to pass in so that 5 matches the formalparameter
type of the method being called?When you say "call bean methods", I assume you mean
that you are setting properties on a JavaBean? If so,
then use the java.beans.Intospector
Also take a look at [url
http://jakarta.apache.org/commons/beanutils.html]the
Jakarta Commons BeanUtils libraryThanks, I think that the MethodUtils class might solve my problem.