Clarification of JavaLive delegates criticism?

From: Jeffrey T. Smith (Geiger581_at_netscape.net)
Date: 06/22/04 

Date: 21 Jun 2004 20:44:36 -0700

Back when the new J2SE1.5 features were announced, there was a
JavaLive community chat
(http://java.sun.com/developer/community/chat/JavaLive/2003/jl0729.html)
in which Neal Gafter explains the Sun stance on lack of support for
delegates:

... There are serious semantic problems with trying to add delegates
to a language in a consistent way. The main problem is that once you
call the delegate, the original class instance is no longer part of
the call chain, so overriding in the original class no longer takes
precedence over the delegate. ...

Could someone please explain this to me a little more fully? It
sounds like he's saying that delegates cannot follow a subclass call
chain if they are created from an object stored in a superclass
reference, but I can't tell if he means overriding delegates
themselves. I would like to know:
1) What exactly does he mean in less ambiguous terms? (Or maybe just
simpler terms; it's been a while since my college programming
languages course.)
2) What an example of delegates 'failing' like this would look like.
3) What is so significant about this problem.

I am already familiar with the 'Truth about Delegates' dialogue
between Sun and MS and the lack of true type safety of C# delegates,
but not understanding this criticism bothers me. Any help would be
greatly appreciated.

Thanks,
Jeff

Relevant Pages

  • Clarification of JavaLive delegates criticism?
    ... in which Neal Gafter explains the Sun stance on lack of support for ... There are serious semantic problems with trying to add delegates ... but I can't tell if he means overriding delegates ... What exactly does he mean in less ambiguous terms? ...
    (comp.lang.java.help)
  • Re: Clarification of JavaLive delegates criticism?
    ... > JavaLive community chat ... > in which Neal Gafter explains the Sun stance on lack of support for ... There are serious semantic problems with trying to add delegates ... reason for not implementing them to feed to the Java "Community Process". ...
    (comp.lang.java)
  • Re: Clarification of JavaLive delegates criticism?
    ... > JavaLive community chat ... > in which Neal Gafter explains the Sun stance on lack of support for ... There are serious semantic problems with trying to add delegates ... reason for not implementing them to feed to the Java "Community Process". ...
    (comp.lang.java.help)