try/catch and loop

[King W.Wang]

Hi all,
is it possible or is it good practice to enclose try/catch in a loop, as:

for (...) {
try {
......
}
catch (...) {
......
}
}

Many thanks

Weichao

[Johnny]

Re: try/catch and loop

It's certainly possible but only sensible if you want to do something in a
loop. If this is the case you'd usually be better off putting the try/catch
block outside the loop.

"King W.Wang" <king_wwang@yah oo.de> wrote in message
news:51d6351d.0 308060845.7dc61 d00@posting.goo gle.com...[color=blue]
> Hi all,
> is it possible or is it good practice to enclose try/catch in a loop, as:
>
> for (...) {
> try {
> ......
> }
> catch (...) {
> ......
> }
> }
>
> Many thanks
>
> Weichao[/color]

[john bailo]

Re: try/catch and loop

Johnny:
[color=blue]
> It's certainly possible but only sensible if you want to do something in a
> loop. If this is the case you'd usually be better off putting the try/catch
> block outside the loop.[/color]

ok, but here's another question. can you put it
in a loop AND set the loop condition based on
catching an error -- that is, say i want to 'retry'
and operation 3 times IFF it throws an error. can
i use the results of the catch as an evaluator in
the while loop

string e = "";
int count = 0;
while (e=="") and (count<3){
try {
//connect to database
}
catch (Exception eq) {
e=eq.ToString() ;
count+=1;
}
}



--
dean '04

http://deanforamerica.com

[cvissy]

Re: try/catch and loop

As far as I know you can do something like that, but its not a good
idea to base your program flows on exceptions.

Rather have your program flow well structured to catch your exceptions
and deal with them immediately.

The example you gave leaves you open to a few problems because you are
making a general catch to all exceptions - maybe a
ClassNotFoundEx ception occurs and you want to tell the user that they
can find the driver file, or a SQLException occurs and you must inform
the user that there is a problem with the JDBC:ODBC bridge. Neither of
these situations would be helped by simply catching a generic and
looping.

[john bailo]

Re: try/catch and loop

cvissy:
[color=blue]
> As far as I know you can do something like that, but its not a good
> idea to base your program flows on exceptions.
>
> Rather have your program flow well structured to catch your exceptions
> and deal with them immediately.
>
> The example you gave leaves you open to a few problems because you are
> making a general catch to all exceptions - maybe a
> ClassNotFoundEx ception occurs and you want to tell the user that they
> can find the driver file, or a SQLException occurs and you must inform
> the user that there is a problem with the JDBC:ODBC bridge. Neither of
> these situations would be helped by simply catching a generic and
> looping.[/color]

excellent advice. i agree with you. AP in ANG suggested a do loop, that
lets the catch increment ( counter++ ) and runs 3 tries. i like your idea
that the catch should be more discriminating and so i could build a
catch(exception e) case statement that only increments the loop for
specific conditions, or does a break; if there are conditions under which
the jdbc connect should not be retried.



--

http://geeks4dean.com

geeks for dean '04