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RE: ACTION-58 Look into issues surrounding the use of the 'any' type in the IDL

From: Jo Rabin <jrabin@mtld.mobi>
Date: Tue, 28 Aug 2007 08:19:30 +0100
Message-ID: <C8FFD98530207F40BD8D2CAD608B50B4600400@mtldsvr01.DotMobi.local>
To: <public-ddwg@w3.org>

My 2 Euro Cents on this as follows:

a) I think the context key needs to be of a known standard type between implementations - I am not sure I am happy with an integer, I'd be happier with a string which allows more flexibility. That said, I'd be equally happy with any other arbitrary length structure or happier still with an opaque Object.
b) I don't think an instance of a context key is portable between implementation types
c) it may be portable between instances of the same type - that's up to the implementation
d) I'm not sure I understand when Rhys says that a context key doesn't identify a context, because inter alia it seems to me that it does identify aspects of a context but only to instances as discussed above
e) I am having difficulty with how persistent a context key needs to be. When discussed in the context of a 'session', I find this difficult to reconcile with the idea of the API being implemented in a RESTful way.


> -----Original Message-----
> From: public-ddwg-request@w3.org [mailto:public-ddwg-request@w3.org] On
> Behalf Of Rhys Lewis
> Sent: 28 August 2007 08:00
> To: 'Matt Womer'
> Cc: 'Josť Manuel Cantera Fonseca'; public-ddwg@w3.org
> Subject: RE: ACTION-58 Look into issues surrounding the use of the 'any'
> type in the IDL
> Hi Matt,
> Yes, I think the key has to be completely opaque.
> I'm not sure I get the distinction between using some type of hash on an
> instance of a context and an  integer. As long as the user of the key
> can't tell what's inside it, without asking the implementation of the DDR,
> it doesn't really matter. Integers are just easier to hand around and are
> of predefined length.
> So, I think we are both saying the following:
> - The context is an implementation-specific data structure that is
> internal to the DDR implementation
> - The context key is an opaque way for a user of the DDR to refer to a
> particular context
> - Users of a DDR get a context key in response to specific operations.
> These include DDR operations to
>   identify a context from a set of HTTP headers, for example.
> - Users of the DDR can ask questions about the context. In doing so, they
> supply the appropriate context
>   key to the appropriate DDR API.
> - Users of the DDR cannot infer anything about the context directly from
> the value of the context key
>   itself. In particular, the key does NOT encode the context.
> - Context keys are NOT portable across different implementations of DDRs
> Whether the key is an integer or a hash of some kind doesn't really
> matter. I think in practice that integers would be simpler, but that's
> just an implementation detail.
> Does that help?
> Best wishes
> Rhys
> -----Original Message-----
> From: Matt Womer [mailto:mdw@w3.org]
> Sent: 27 August 2007 17:47
> To: Rhys Lewis
> Cc: 'Josť Manuel Cantera Fonseca'; public-ddwg@w3.org
> Subject: Re: ACTION-58 Look into issues surrounding the use of the 'any'
> type in the IDL
> Hi Rhys, Josť, DDers,
> On Aug 1, 2007, at 3:32 AM, Rhys Lewis wrote:
> > If all that sounds correct, then the 'handle' for the context key
> > merely has to identify it within a session that a caller has with the
> > DDR.
> > So,
> > can't it just be an integer?
> Thanks for writing this up, it helped me understand where the confusion is
> coming from.
> I think of the Context Key IS the opaque handle itself.  It is a handle to
> the "Context", which is an implementation specific structure in and of
> itself.
> I assumed that from the name that it was a 'key' in a list/hash/map of
> contexts, and I think from your email that this isn't what you're
> thinking.  RIght?
> What do other folks think?
> -Matt Womer
> mdw@w3.org
> W3C Team -- http://www.w3.org/
> Mobile Web Initiative Lead Americas
> Team Contact: MWI DDWG, POWDER, Voice Browser
Received on Tuesday, 28 August 2007 07:19:44 UTC

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