Re: Choosing not to throw exceptions like IllegalArguementException

Joshua Cranmer <Pidgeot18@verizon.invalid>
Sat, 07 Jun 2008 14:40:36 GMT
Robert wrote:

id' like to share with you a design view i've learned since i work. When
i have to deal with nulls, i don't throw an IllegalArguementException
any more, i just return a default value (or void). It gives better
robustness to the program i think.

On the other hand, it requires a better knowledge of the internals when
a bug a seen, since the program doesn't blow up compeltely.

Ultimately, I think the question of throwing an exception or returning a
value comes down to one key point: is the situation "expected"? For
example, it would not be an exceptional circumstance to use List.indexOf
on an object not included in the list, so an exception here does not
make sense. On the other hand, it would be exceptional to open a
connection to a nonexistent server, so an exception there does make sense.

The question I ask to you is "Does an argument of null imply retrieving
the default value (or other special code), or is it something that
should not be occurring?" In my experience, the former is of quite
limited utility, mostly limited to some sort of configuration semantics.

Beware of bugs in the above code; I have only proved it correct, not
tried it. -- Donald E. Knuth

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