Re: reflection problem
On 25 Lug, 16:44, Daniel Pitts <googlegrou...@coloraura.com> wrote:
On Jul 25, 7:33 am, xar...@gmail.com wrote:
hi all, i got a problem with this bunch of code:
[CODE]
Manager boss = new Manager("Paul Brown", 1000, 500);
Class c = boss.getClass();
try
{
Field field = c.getField("bonus");
Integer newBonus = field.getInt(boss);
newBonus = newBonus + 200;
field.setInt(boss, newBonus);
}
catch(NoSuchFieldException nsfe)
{
System.out.println(nsfe.getMessage());
nsfe.printStackTrace();}
catch(IllegalAccessException iae)
{
System.out.println(iae.getMessage());
iae.printStackTrace();}
[/CODE]
i got a class Manager with a public (otherwise i'd get a
NoSuchFieldException) Integer bonus field. i'd like to modify it via
reflection, but i get an error at this point:
Integer newBonus = field.getInt(boss);
[CODE]Exception in thread "main" java.lang.IllegalArgumentException:
Attempt to get java.lang.Integer field "dynamicbinding.Manager.bonus"
with illegal data type conversion to int
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIllegalArgumentException(Unknown
Source)
at
sun.reflect.UnsafeFieldAccessorImpl.newGetIntIllegalArgumentException(Unknown
Source)
at sun.reflect.UnsafeObjectFieldAccessorImpl.getInt(Unknown Source)
at java.lang.reflect.Field.getInt(Unknown Source)
at reflection.Main.main(Main.java:30)[/CODE]
illegal data type conversion to int? what does it mean? how can i fix
this? thank you all :)
getInt returns (int), where as your Bonus value is an Integer.
You can either change the type of your bonus to int, or you can use
Integer newBonus = (Integer)field.get(boss);
Although, I'm curious why you wish to use Reflection. If your project
is simply to learn more about reflection, thats fine, but usually
using reflection for this sort of thing is a Bad Idea (TM). Perhaps
if you shared your goal with the group, we could suggest a better way.
thank you man. although it sounds me funky to get an error with the
int/Integer assignaments (wrapper classes shouldn't give such
problems), i've tried your solution, and this one too:
int newBonus = f.getInt(boss);
but i keep on getting the same error at the same line. and finally
yes, my project is simply to learn more about reflection. i know i
could have simply done this via standard set/get methods :)
plus, to allow a pure OO programming, i'd avoid to change the type of
bonus from Integer to int :)