Hi Gilles, Gilles Sadowski wrote:
>> > [...] >> > >> > Has anyone of you considered the usage of an exception context? We >> > introduce this with lang3 (http://commons.apache.org/lang/api-3.0- >> > beta/org/apache/commons/lang3/exception/ExceptionContext.html) and it >> > basically adds a map with key/value pairs to the exception itself. >> > >> > This concept has worked out quite nicely especially in situations where >> > code can nest deeply in conjunction with user-provided code that make >> > calls in the core functionality again. >> > >> > The nice part is that you can add information at each position that can >> > provide useful information (assuming MathException implements this >> > interface): >> >> We didn't consider that :-( >> It seems very interesting to me. >> >> What do other think about it ? > > I'm not so enthusiastic: Right now I don't see how it will improve the > current situation in CM. An example might help me understand the > advantages. However I'm not really happy with the current localization > scheme, so I would not be against trying something else if it can be > improve that way. > [One nice thing might be that we would not be limited to one "general" and > one "specific" problem description. > One not so nice thing is that we wouldn't have different exception types, > each with a specific interface.] > >> > [...] > >> > >> > ... and remember, you can add the context interface to various >> > exceptions, you don't have to maintain a hierarchy. >> > ... and your users can add values also that are interesting e.g. for >> > their stop condition without wrapping or inventing new exceptions. > > Do I understand correctly that, if we go down that road, there would only > be a single exception (every failure will raise the same exception)? No, not at all, but your exceptions would provide all the same mechanism to add valuable information up the stack. Have a look at the implementation of ContextException and ContextRuntimeException. It's quite hollow, the real code is in DefaultExceptionContext i.e. you could easily create also a IllegalArgumentContectException derived from IllegalArgumentException. And since the ExceptionContext is only an interface you might even replace ther DefaultExceptionContext with something like LOcalizedExceptionContext that has additional language support. > If the aim is only for printing the whole context, it is indeed very > flexible (adding a lot of info is easy). But if the caller wants to trap > and act on a particular condition (a part of the context), isn't it more > difficult than catching a specific exception? As I said, keep the hierarchy, but you might be able to trim it down more easily, because you don't have to invent a new one simply because you want to provide an additional information. > Examples are really needed to figure out the actual use-cases for CM and > users of CM. Cheers, Jörg --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
