On Jan 23, 2007, at 7:39 AM, Karan Malhi wrote:
Ok,
I got stuck at one point here. To be clear i am giving an example
below:
Lets say we have an interface X in java 5 which has a method which
returns a
type Y as shown below
public interface X {
Y a();
}
The same interface in Java 6 is, but it adds a method named b, which
returns a type Z which is only available in java 6
public interface X {
Y a();
Z b();
}
Now lets say I have an existing class named XImpl
public class XImpl implements X {
public Y a(){ return new Y();}
}
If I compile the above XImpl with Java 5, it would work fine,
however the
compiler will complain in Java 6.
Using dynamic proxies would work fine at runtime in both Java 5 and
Java 6.
My question is , how do i satisfy the Java 6 compiler before i run the
program to generate the dynamic proxy?
Two thing pop to mind, the first is to simply always build on 5 but
we would be able to run on 6, but that would defeat the purpose of
this question :)
We could have our implementation class not implement the interface
and dynamically add the interface later. To keep ourselves sane we
could make our own copy of the interface. Using your example:
1.5
public interface X {
Y a();
}
1.6
public interface X {
Y a();
Z b();
}
OpenEJB
public interface OurX {
Y a();
}
public class OurXImpl {
Y a() { return doSomething(); }
}
Dynamic proxy 1.5 {
public class Ximpl implements X {
private final OurXImpl x;
Y a() { return x.a(); }
}
Dynamic proxy 1.6 {
public class Ximpl implements X {
private final OurXImpl x;
Y a() { return x.a(); }
Z b() { throw new UnsupportedOperationException(); }
}
This should work. Alternatively, we could, as David suggested, try
to ship our own version of the missing javax.sql classes. I'm not
sure what is easiest.
-dain
