Dynamic typecasting in java...is it possible?

Question

Hi All
i have a requirement in which i do not know the exact subclass to what i have to typecast to during compile time. I am calling it xyzclass, which i do not know till run-time.
xyz can be A or B or C class.
xyzclass xyzobj = (xyzclass) superclassofxyz
Thanks in advance.
kk.

Answer 1

If your XYZClass, A, B and C classes are fixed, you could try a double
dispatch pattern (aka visitor pattern). Here's the idea:public interface Visitor {
   public void isXYZClass(XYZClass visitee);
   public void isA(A visitee);
   public void isB(B visitee);
   public void isC(C visitee);
public interface Visitee {
   public void knockknock(Visitor visitor);
public class XYZClass implements Visitee {
   public void knockknock(Visitor visitor) { visitor.isXYZClass(this);
   // more code here ...
public class A extends XYZClass {
   public void knockknock(Visitor visitor) { visitor.isA(this);
   // more code here ...
public class B extends XYZClass {
   public void knockknock(Visitor visitor) { visitor.isB(this);
   // more code here ...
public class C extends XYZClass {
   public void knockknock(Visitor visitor) { visitor.isC(this);
   // more code here ...
}... your class needs to implement the Visitor interface; it simply knocks
on the door of any XYZClass (or derived class) and the Visitee simply
calls the Visitor back again through the correct method.
kind regards,
Jos