On 09/24/2015 04:05 PM, Gilles wrote:
On Thu, 24 Sep 2015 08:43:38 -0500, Ole Ersoy wrote:
On 09/24/2015 06:31 AM, luc wrote:
Le 2015-09-24 04:16, Ole Ersoy a écrit :
On 09/23/2015 03:09 PM, Luc Maisonobe wrote:
CM is not intended to be a design pattern people should mimic. We are so bad at
this it would be a shame. No one in its right mind would copy or reuse this
stuff. It is for internal use only and we don't even have the resources to
manage it by ourselves so we can't consider it as a path people should follow
as we are leading them. Here we would be leading them directly against the wall.
Hehe - I think that's like Michael Jordan saying - "Guys, don't try to
be like me. I just play a little ball. Dunk from the free throw
line. Six world championships, but THATs it!". In any case, I really
appreciate you and Gilles taking the time to talk. Luc (And possibly
Gilles) - I can actually see why you are getting a bit annoyed,
because I'm ignoring something important.
I've been doing 90% NodeJS stuff lately (Which is event loop based and
relies callbacks) so I forgot one very important thing that I think
you have both tried to tell me. The exception undoes the current
callstack / breaks the current program flow, bubbling up to the
handler. Thaaaats a good point.
OK - So scratch the callback thinking for synchronous code. The
Lombok stuff should still be good though and hopefully some of the
callback discussion around and asynchronous option - I hope! Geez.
What do you think about having one exception per class with an Enum
that encodes the various types of exceptional conditions that the
class can find itself in? So in the case of
LevenbergMarquardtOptimizer there would be a:
- LevenbergMarquardtOptimizerException:
- LevenbergMarquardtOptimizerExceptionEnum
When the exception is thrown it sets the Enum indicating the root
cause. The enum can then be used as a key to lookup the corresponding
message.
Any better?
Sure. I would suggest adding some parameters to help the upper level formatting
a meaningful message (say the number of iterations performed if you hit a max
iteration, so users become aware they should have set the limit higher). Nothing
over-engineered, a simple Object[] that can be used as last argument to
something
like String.format() would be enough.
Brilliant - I'll setup a repository and start experimenting. Thanks again,
- Ole
I don't understand what Luc proposed.
But just having "Object[]" mentioned makes me shiver... :-{
Thanks to the "ExceptionContext" it is readily possible to add as many
"messages"
as we want to be displayed. [There is no need to ask the caller to use
"format()"
as it is done in CM.]
And there are also a methods for setting and getting an "Object".
I'd be for using more (possibly "local") exceptions if we want to convey
more, and more specific, information. This should be done with getters that
return typed information, not "Object"s.
Javascripters do what Luc is advocating all the time, so I'm used to it.
If the exception is specific to the class throwing the exception then we could
attach a reference to the instance throwing the exception and use Lombok to
generate binary getters.
Cheers,
- Ole
Gilles
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