The Right Approach to Exceptions

[foobar]

On Tuesday, 21 February 2012 at 15:38:15 UTC, Juan Manuel Cabo 
wrote:
>> This works:
>> // note: the int parameter above isn't static
>> dbConn.query("select age from people where id='foobar'");
>> throw new WithErrorCode!FileNotFoundException(
>>           db.rs.getValue(1), "file not found");
> ...
>> Can you offer a real world use-case where the above isn't 
>> sufficient?
>
>
> What happened is that a file wasn't found. What one wants to 
> catch is
> a FileNotFoundException.
>
> Do you suggest that I have to:
>
>    try {
>        ...
>    } catch (FileNotFoundException ex) {
>        ...
>    } catch (WithErrorCode!FileNotFoundException ex) {
>        ...
>    } catch (WithRainbows!FileNotFoundException ex) {
>        ...
>    }
> and so on?
>
> --jm

FileNotFoundException is the super class of the others so the 
first catch clause is enough. in fact, the others will never be 
called if listed in the above order.