[mapserver-dev] Different WMS versions...

[David Graham]

Steve,

That is the right way to go about it.  If mapserver was written in an 
object oriented language, you would extend and override functions.  You 
would likely then create a factory to generate the correct version of 
the object to execute the commands.  Something like:

CapabilitiesDoc cd = CapablilitiesDocFactory.getDoc( Version v );

Not quite as graceful in C, but you can still capture some of the 
concepts.  Instead of a factory you might have a couple of high level 
functions that route the code path to various sets of functions.

Another aproach in C is pass the function pointers.  You can create a 
function factory and pass back the function pointer required.  But I 
find this to be messy (that is why there is C++) and can be difficult to 
maintain (especially if you were not the original devleoper).

Just some thoughts.

Dave Graham

Steve Lime wrote:

>As we add new support for new versions of the OGC specs how should that
>be handled in the code? I was thinking, although verbose perhaps we
>should just make copies of the various functions that correspond to the
>version and then have the main handler check the version and hand off to
>the appropriate function. That might make the code easier to maintain
>long term since there wouldn't be tons of if-then statements to sort
>through. Easier to retire old version support as well since it would be
>seperated out nicely. I'm thinking specifically about the request to add
>WMS 1.1.1 getCapabilities.
>
>Thoughts?
>
>Steve
>
>Stephen Lime
>Data & Applications Manager
>
>Minnesota DNR
>500 Lafayette Road
>St. Paul, MN 55155
>651-297-2937
>
>
>  
>

-- 
David W. Graham
Director of Geospatial Applications Development
information integration and imaging, LLC
201 Linden St, Third Floor
Fort Collins, CO 80524
(970) 482-4400
dgraham at i3.com
http://www.i3.com