About extending parameterized interfaces...

Question

Hi all,
I have a (hopefully?) quick question about generics. I have the following interface:
public interface MessageHandler<T extends Message, S extends NodeInterface> extends Handler {
     public Class<T> getHandledClass();
     public void nowHandle(S ni, T msg);
}Now, I have a whole family of classes that are going to implement this interface, such as the following:
public class LivenessReplyHandler implements MessageHandler<LivenessReply, PardooNodeInterface> {
public class LivenessRequestHandler implements MessageHandler<LivenessRequest, PardooNodeInterface> {
}etc. In each case, the right hand type is always PardooNodeInterface. Now since this is a family of classes, I'd like to do something more along these lines:
public interface PardooMessageHandler<T extends Message> extends MessageHandler {
     public void nowHandle(PardooNodeInterface ni, T msg);
}And then clients simply extend PardooMessageHandler:
public class LivenessReplyHandler implements PardooMessageHandler<LivenessReply> {
public class LivenessRequestHandler implements PardooMessageHandler<LivenessRequest> {
}That is, extending from PardooMessageHandler automatically implies that type S in nowHandle of MessageHandler is of type PardooNodeInterface. Now you may ask "Why don't you just go hard-code PardooNodeInterface into type S in MessageHandler then?" Well, that's because this is just one family of handlers -- in the end, there will probably be a half-dozen more, each using a different type for S.
I feel as this can be done using generics... Just not clear on the syntax :(
Thanks,
shadowmatter

Answer 1

I think this would work:
public interface PardooMessageHandler<T extends Message> extends MessageHandler<T,PardooNodeInterface> {
}