[fdo-internals] Enhanced Exception Types in FDO

[Frank Warmerdam]

Greg Boone wrote:
> Hi All,
> 
>  
> 
> I am currently struggling with the topic of error handling and 
> exceptions in FDO, FDO Providers and applications that use them. I would 
> like to get some feedback from the community on how we could possibly 
> resolve this issue in the next planned release of FDO (trunk).

Greg,

I wonder if you could talk us through a couple examples where the current
system is inadequate.  I can see value in adding some additional exception
classes to support finer grained error handling.

I'm concerned that exposing native error codes and provider id's as part
of exceptions is giving up on genericity in the FDO API.  But if you can
illustrate cases where this is critical it could be ok.

 From the point of view of the GDAL provider, I have no need to provide
finer grained error information from GDAL itself.  GDAL has a very thin
set of native error codes, and essentially the error text (which is
formatted with potentially lots of detail) is the important cargo.

Of course, I have not done much application writing on FDO so it is hard
for me to know what things applications writers are having trouble handling.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent