[solved] Re: accessing subclasse methods and fields with introspection / reflection

"Samy" <samy@samy.com>
Fri, 4 Aug 2006 17:02:02 +0200
Ooops, my fault.
Well, the fault of the code hierarchy in fact. I found a way to fix it.
Thank you a lot for the example. I had to test it before I could believe it
worked with your code and not with mine ;-)

The problem was that some of the classes I had were simulating inheritance
with delegating calls to an internal field ('has a' relation) Here is the
skeleton of the structure I had:

import java.lang.reflect.Method;

interface IA {
 public String[] methodIA();
 public void printMethods();

interface IB {
 public String[] methodIB();

interface IC {
 public String[] methodIC();

abstract class MandatoryLegacy {
 public abstract void mMandatoryLegacy();

/** this class is the only one really implementing IA*/
class AA implements IA {
 public String[] methodIA(){return null;}
 public void printMethods() {
  Method[] lMethods = getClass().getMethods();
  for (int i=0; i<lMethods.length; i++) {
   System.out.println("- " + lMethods[i].getName());

/** Here is the *fake* implementation of IA */
abstract class A extends MandatoryLegacy implements IA {
 AA mAA = new AA();
 public void mMandatoryLegacy() {}
 public String[] methodIA() {return mAA.methodIA();}
 public void printMethods() {mAA.printMethods();}

abstract class B extends A implements IB {
 public String[] methodIB() {return null;}

class C extends B implements IC {
 public String[] methodIC() {return null;}

public class testReflect {
 public static void main(String[] args) {
  C mC = new C();


It outputs:
- *printMethods*
- *methodIA*
- hashCode
- getClass
- wait
- wait
- wait
- equals
- notify
- notifyAll
- toString

See, all the methods IB, IC etc. are missing. Anyway, my problem is now
solved. Thank you

The fix was to add a 'specialPrintMethods(Class iClass)' method to AA and
use it in A So A becomes:

abstract class A extends MandatoryLegacy implements IA {
 AA mAA = new AA();
 public void mMandatoryLegacy() {}
 public String[] methodIA() {return mAA.specialPrintMethods(getClass());}
 public void printMethods() {mAA.printMethods();}

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