Re: Exception Names
Mike Schilling wrote:
Tom Anderson wrote:
I also think that whether an event is exceptional has at best a
marginal connection to whether it's a good idea to use an exception
for it. I think that's an overly literal and dogmatic approach to
take.
The you like
int i = 0;
try
{
while (byte b = barray[i++])
Syntax error? The intent is clear, though.
{
// process b
}
}
catch (IndexOutOfBoundsException ex)
{
; // OK, we're done with the array
}
If not, why not?
IIRC, Bloch uses this (or a close relative) in "Effective Java"
as an example of why loop control by exception is unreliable in
addition to being slow. If we fill in the loop body a bit:
try {
while (true) {
byte b = barray[i++];
flimFlam(b);
jimJam(b);
whizBang(b);
}
}
catch (IndexOutOfBoundsException ex) {
// Done with the array? Or were we only part
// way though when one of the called methods
// malfunctioned and threw up?
}
To be sure you'd caught the expected Exception instead of some
other unexpected Exception, you'd need to do something like call
getStackTrace() and check that the Exception originated in the
expected place. Note that just checking the class and method
name aren't enough if any of the called methods make direct or
indirect recursive calls back to the method containing this
loop; if that's a possibility I think you'd need to grab a
stack trace of a point inside the looping method and double-
check its depth against that of the thrown Exception ...
--
Eric.Sosman@sun.com