The DOM and the victim, the iconoclast and the believer

David Brownell david-b at
Sun Jan 16 18:30:27 GMT 2000

Didier PH Martin wrote:
> David, you are right on this point. Some ORB just throw an exception when we
> access a non exiting member. I am actually checking where in the OMG specs
> it is explicitely mentionned. It discovered that it is not all ORB that has
> this behavior. Now the question is: Is this behavior (to throw an exception
> when a required member is not there) is a specified characteristic or simply
> because some ORB manufacturers are more clever than others.

CORBA 1.0 defined an exception for that purpose; I don't know why
any ORB wouldn't report that system exception when the client calls
a method that doesn't exist, other than a bug.  Certainly succeeding
by calling some other method is incorrect.

There's also Node.getOwnerDocument().getImplementation().hasFeature()...

> Yes memory menagement is problematic, I agree. But also to have a single
> binary signature convention may be against manufacturers interests since I
> am no longer the prisoner of a single ORB vendor.

That's another one of the issues.  But "inout" parameters were always
the cause of some major chaos.

> David said:
> That said ... I think I would agree that changing already-published
> interfaces was pretty much against the spirit of IDL.  It'd have been
> much more natural to define a new module (C++ namespace, Java package)
> that inherited the old interfaces and added new methods:  no change
> of current interfaces/contracts.  IDL has multiple interface inheritance
> to allow that style of evolution, among other reasons.
> Didier reply:
> Yes I agree on this, on several ORB that I made my test, inheritence is
> working well, so, as you said, if suffice to have the new interface to
> inherit from the old. That way, we know waht is part of the old contract and
> what is part of the new one.

Again, if it is NOT working in some ORB, it's got bugs that'd make me
avoid using it.  Multiple interface inheritance has again been part of
IDL since CORBA 1.0, and it's not like it's hard to get right.

- Dave

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