Re: Java exception model. Was: Re: Ada Quality and Style book discussion ("_Type" suffix)

[Brian May <bam@snoopy.apana.org.au>]

>>>>> "Dmitry" == Dmitry A Kazakov <mailbox@dmitry-kazakov.de> writes:

    >> How does one decide into which class a new exception should go?

    Dmitry> Checked. I cannot imagine any unchecked exception other
    Dmitry> than generated by the environment (hardware/OS.)

I think It also depends on how likely this error is going to occur,
and if you want to be able to handle this error condition gracefully
in your code or not.

So something like "CRC error" in a received packet would definitely
get checked, because you don't want your program to collapse in a heap
if it receives a corrupt packet.

If however, after checking the CRC, you check it again (maybe for
paranoid reasons inside lower level functions) using some sort of
assert statement, and it is now wrong, you may decide this condition
should never occur (implies some sort of software bug or hardware
error), and you don't want to try and recover from this condition. In
fact, you may even want to abort immediately without trying to clean
up anything.

So if an exception is a result of a non-recoverable software bug or a
non-recoverable hardware error, it probably should go
unchecked. Otherwise it should be checked.
-- 
Brian May <bam@snoopy.apana.org.au>