How to make a class confirm to a specific abstract structure?

Question

I have a class which should extend one of the swing component and on the other hand implement an interface. i.e.
public class A extends JTable implements UpdateData
In some other class
public class UpdatePanel extends JPanel
public void setUpdateComp(JComponent anJc)
updateCompJc = anJc;
// but here i want to use methods of interface UpdateData
// which i cannot be sure of that anJc implements those methods since
// its an instance of JComponent.
// One sol in my mind is to cast with UpdateData and check for
// ClassCastException.
// Is there any other way of doing this such that i don't have to cast
// between JComponent and check ClassCastException to be sure that it
// implements reqd. interface
Thanks and reagrds,
Amit.

Answer 1

Hi,
if you use the declaration
public void setUpdateComp(UpdateData anJc) { ..... }
instead, then only an instance of a class can be passed to that method, that has UpdateData implemented - but, you are then restricted to the methods of the interface - if you want to use others, you have to check for the instanceOf this parameter and cast it to that class afterwards.
greetings Marsian