Re: [ws-caf] More thoughts on contexts (was RE: [ws-caf] Agenda forthe demo application)

[Greg Pavlik <greg.pavlik@oracle.com>]

Green, Alastair J. wrote:

>Hi Jim,
>
>Timeouts: it all depends what the timeout means. The hard part is the
>interpretation, and I think that must be known to the specific
>processor, not to the general contexts processor. So once again, we seem
>to end up employing a servant to open the door, when we are perfectly
>able-bodied.
>
Has Jim's point about representation shifted to something about 
processing here? What is a "general contexts processor"? The only such 
thing I can see in the specification that might match this description 
is the context service (or activity service), and the interpretation of 
timeout is not ambiguous. Or perhaps you mean to suggest that the 
timeout semantic of a higher level service might be inordinately 
constrained by the definition that is provided at the lower level?

>
>A standard model for hierarchical contexts is more interesting. One
>question I have is: how easily can I construct disjoint hierarchies?
>Let's say that the interposition concept is useful for transactions, but
>we want a flat security domain. I'm not sure what that would mean in
>practical processing terms either (carried together in a contexts
>wrapper? Separately?).
>
I think the specs are somewhat unclear, and I'll say frankly that I've 
been puzzled by language that suggests multiple ALS's may augment a 
single context. As a practical matter, I would expect them to be separate.

>
>Related question: in WS-TXM there is heavy emphasis on interposition,
>which is an example of hierarchical context. However, I cannot discern
>from the specs how the WS-CTX hierarchy is used to help this.
>Specifically, the WS-TXM protocols appear to defer to WS-CF for
>interpositon, but WS-CF does not seem to mandate any defined
>relationship between a Coordination Service and an ALS -- which seems to
>be the point of contact with WS-CTX as it currently stands.
>  
>
Wouldn't you agree that WS-Context focuses on nested hierarchies rather 
than interposed relationships? In this respect, WS-Context is quite 
helpful.

>Alastair
>
>-----Original Message-----
>From: Jim Webber [mailto:Jim.Webber@newcastle.ac.uk] 
>Sent: 15 February 2004 23:55
>To: Green, Alastair J.; ws-caf@lists.oasis-open.org
>Subject: RE: [ws-caf] Agenda for the demo application
>
>Hey Alastair,
>
>[ker-snip]
>
>I think the WS-Context context structure gives you (at least) two wins
>over "ad-hoc" XML in your header blocks.
>
>i) There's a bunch of standard stuff like timeouts which is useful.
>ii) It gives you access to a standard model for hierarchical contexts
>which is also useful.
>
>Jim
>  
>