[fdo-internals] RFC 20 for review

[Thomas Knoell]

Hi Harris,

Thanks for the comments.

As for the motivation, currently there is no way to add a new capability to FDO without the need to implement that new capability in all providers that want to use the updated FDO code base. The new interface concept provides the chance to actually do this as capabilities can be added without changing FDO. As a result, only the provider that wants to support the new capability needs to implement the support.

As for the error handling, this is documented in RFC 20. If a user calls a function - for example GetBooleanCapability for a capability that returns an Int32 - the function would set the flag "isUnknown" to true. It is up to the caller to check this flag an react accordingly. For example, the caller could either use a default value that is appropriate in this case or throw an exception. But this is all up to the caller.

Thanks

  Thomas


From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Haris Kurtagic
Sent: Tuesday, July 08, 2008 7:45 PM
To: FDO Internals Mail List
Subject: RE: [fdo-internals] RFC 20 for review

I think this is much more complicated way of exposing capabilities rather than like it says in RFC simplifying.

I am not sure about motivation for it. For example If application is build with newer version of FDO core I would think that older provider will not be used anyhow .
I can't see reasons when application which is build for use with one version of FDO libraries will use older providers.
Also Isn't it going to be a problem when application is linked with one version of FDO core libraries and provider is like build with another. With current dll naming it is not possible I think ?

I couldn't find in RFC error handling for case when function of wrong type of capability is executed for existing capability ( e.g. Call GetBooleanCapability for Int32 ) ?

Haris

From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Thomas Knoell
Sent: Tuesday, July 08, 2008 11:38 PM
To: fdo-internals at lists.osgeo.org
Subject: [fdo-internals] RFC 20 for review

Hi,

RFC 20 (http://trac.osgeo.org/fdo/wiki/FDORfc20) has been posted. It proposes a simplification of the FDO capability interfaces. Please review the RFC and let me know of any questions and suggestions you may have. The review deadline is set for end of day July 18th.  It is intended to request a vote on the RFC afterwards.

Thanks

  Thomas

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