The Right Approach to Exceptions

[Andrei Alexandrescu]

On 2/18/12 8:00 PM, H. S. Teoh wrote:
>>  From this and other posts I'd say we need to design the base exception
>> classes better, for example by defining an overridable property
>> isTransient that tells caller code whether retrying might help.
>
> Just because an exception is transient doesn't mean it makes sense to
> try again. For example, saveFileMenu() might read a filename from the
> user, then save the data to a file. If the user types an invalid
> filename, you will get an InvalidFilename exception. From an abstract
> point of view, an invalid filename is not a transient problem: retrying
> the invalid filename won't make the problem go away. But the application
> in this case *wants* to repeat the operation by asking the user for a
> *different* filename.
>
> On the other hand, if the same exception happens in an app that's trying
> to read a configuration file, then it *shouldn't* retry the operation.

I'm thinking an error is transient if retrying the operation with the 
same exact data may succeed. That's a definition that's simple, useful, 
and easy to operate with.

Andrei