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From "Stephen Colebourne" <>
Subject Re: [collection] Transformer exception handling
Date Sat, 15 Jun 2002 20:42:14 GMT
From: "Ola Berg" <>
> >This technique has the advantage of
> >converting the exception to a runtime exception relatively transparantly,
> >which is more convenient in general.
> Well, IMHO \"convenient\", just as loosely typed languages are convenient
(at first). Declared Exceptions has the advantage that it makes you consider
the exceptional case. You need to. =less error prone code.
> Generally, I see a need for both lax and strict programming styles, for
different purposes. When it comes to exceptions, I\'m all for the principle
that states \"RuntimeException for those things you could foresee (like
NullPointerException), and Exception for those things that can happen no
matter how cautious you are (like IOException)\".

Accepted. (I do use checked exceptions).

> And speaking with architectural lenses on my goggles:
> Isn\'t the problem here that there is more to generic Transformations than
any of the proposed interfaces can handle? Compare with event listeners in
Swing: they are in a sense encapsulated actions/transformations/messengers
(or should invoke a such). But they don\'t allow exceptions to be passed.
You are thus force to handle them elsewhere.
> With that in mind, I am all for keeping Transformations without
exceptions, as long as we/you/me/other can present a decent and supported
pattern (with supporting classes) that solves that generic problem (how to
handle exceptions elsewhere).
> I have done experiments in putting an ExceptionHandler that swallows the
exceptions, but passes them to a different (plugable) handler architecture
as messages, so that the caller doesn\'t have to deal with it. I am not
pleased with my attempts, but something needs to be done, if one wants to be
able to encapsulate operations into generic interfaces, lest we let the
interfaces throw the generic Throwable.

I'm interested - have you looked at Morphos yet??


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