Will instanceof work in this case

Question

I am trying to simplify my code, and here is what i have
i have the below classes :
interface xyz
class A implements xyz
class B implements xyz
i have lot of set/get methos in class A and class B. which are not in xyz.
setfields(Obj) //this obj can be class A or class B
Object ob=null;
if ( obj instanceof A)
ob=(A)obj;
if(obj instanceof B)
ob=(B)obj;
//Here depending on the object i want to use set methods on that particular object. Is it possible?
But when i do this , ob doesn't show the methods in Class A / class B.
Am i doing the correct way.
}

Answer 1

I agree that's a good way to simplify your code, but you had a mistake
in that...
ob=(A)obj; // ob is a instance of Object
because ob is just a object, so it can access only Object's method.
you can correct code like this.
A obj = (A)obj; // obj is a instance of Class A
then, it can access any method in Class A.
and I recommend make a 'int getType()' method in interface and
use that. for example...
interface xyx{
public int getType();
class A implements xyz
public int getType(){return 0;}
class B implements xyz{
public int getType(){return 1;}
setfields(xyz Obj) // this obj is must be instance of class implements xyz
switch(Obj.getType()){
case 0:
A Obj2 = (A)Obj;
break;
case 1:
B Obj2 = (B)Obj;
break;
you can make static int variable or enumeration class for more elegant code.
I'm sorry about I can't explain well so that english isn't my mother tongue. -_-;;