On 9/6/12 5:16 AM, Gilles Sadowski wrote: > Hi. > >>>>>> [...] >>>>>> >>>> I was about to start a new thread too, but refrained to do so for lack >>>> of knowledge on the history of this particular exception. >>>> Check for null is unevenly enforced througout the library, which --to >>>> me-- suggests we shouldn't do it at all and contend with NPE. There is >>>> one potential use, though. I think we should check for null when the >>>> NPE might occur in a different method. >>>> >>>> This is what happens with new Incrementor(int, >>>> MaxCountExceededCallback) : cb is just copied, and fields of cb are >>>> invoked elsewhere: in that case, checking for null does make sense. >>> >>> I think even there we could rely on the JVM, for simplicity. >>> >> Do you mean that we should do nothing, and let NPE occur "naturally"? > I'd think we should opt for this. > >> The origin of the problem might then be difficult to identify. > That's true. But the reason of the problem is an "obvious" bug > (uninitialized variable). > The exception may be raised further down the call sequence, but the stack > trace will provide a one way road to discover the source of the problem. > >> Or maybe you meant that we check for null in that case, but throw NPE >> instead of our own MathNullArgument? > No, it sure is simpler to do nothing in CM. :-) > Otherwise, we'll have to check every reference (for consistency). > >> I would be in favor of the second option. On the other hand it's >> difficult to check that it's consistently applied throughout our code, >> and I can see your point in doing nothing. > So, do we agree?
I would rather fully document what the API does on nulls (which we do in a lot of places now), but can live with the "go boom" for this in some (most?) places if that is the consensus of others. I would prefer at least not to rip out the null checks that we have in a lot of places in the stats package. As a user, I would rather get an IAE with informative message when I pass a not allowed null than an untrapped NPE from somewhere a few layers down in the stack. I would like to preserve the way the code that does null checks today works. Other than that, I am OK dropping the custom [math] exception. Phil > > Gilles > >> Sébastien >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org >> For additional commands, e-mail: dev-h...@commons.apache.org >> > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > For additional commands, e-mail: dev-h...@commons.apache.org > > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
