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Subject: Documentation need for value of context by value (was RE: [ws-caf] Mt Everest and WS-CF)
Greg, Should have replied earlier. Depends on whether the spec has much material on the use and purposes of ws-context, or just a limited summary of what it is. I think this is a question (in one of its formulations) that needs to be covered in all but the shortest explanations. The spec is currently pretty terse, so it may be appropriate to have this in supporting material. Peter > -----Original Message----- > From: Greg Pavlik [mailto:greg.pavlik@oracle.com] > Sent: 27 May 2004 14:17 > To: Furniss, Peter > Cc: Mark Little; Green, Alastair J.; ws-caf > Subject: Re: [ws-caf] Mt Everest and WS-CF > > > Peter, would it simply be satisfactory to address these questions > directly in the FAQ or primer? > > Furniss, Peter wrote: > > >I'll restate the documentation question I raised on this: > > > >Does the specification state what are the advantages of using > >ws-context by-value over and above using a SOAP header with the same > >application information. > > > >Does it state what considerations would lead a designer to choose to > >define a use of ws-context by-value instead of defining a > soap header. > > > >I don't believe the question (which is quite distinct from > the question > >of value OR reference) has ever had a documented answer. It has been > >discussed (at least in Paris, I'm not sure if it was > discussed since), > >but where is the answer ? > > > >I raised it as a documentation question precisely because I > don't want > >force revisitation if the answer is in fact already well > known to most > >of the TC. > > > >Peter > > > >-----Original Message----- > >From: Mark Little [mailto:mark.little@arjuna.com] > >Sent: 27 May 2004 11:42 > >To: Green, Alastair J.; ws-caf > >Subject: Re: [ws-caf] Mt Everest and WS-CF > > > > > >Alastair, I understand why you may want to revisit this, but > obviously > >disagree and don't want the TC process to be unduly stalled. > I cannot > >see what adverse effect going forward with the specification as it > >currently stands has on any referencing specification that > decides not > >to use context by value but instead chooses context by > reference (and > >vice versa). It does neither impinges on the readability of the > >specification nor on the understandability IMO. > > > >I re-iterate that I believe we have already discussed this > subject over > >the past 2/3 months in teleconferences and face-to-face meetings. I > >don't believe that revisiting it will benefit us or the WS-Context > >specification at this stage. What it will do is delay the > adoption of > >WS-Context by other interested groups and by other referencing > >specifications (e.g., WS-CF). I see that as a big disadvantage. > > > >Mark. > > > >---- > >Mark Little, > >Chief Architect, Transactions, > >Arjuna Technologies Ltd. > > > >www.arjuna.com > > > >----- Original Message ----- > >From: Green, Alastair J. <mailto:Alastair.Green@choreology.com> > >To: Mark Little <mailto:mark.little@arjuna.com> ; ws-caf > ><mailto:ws-caf@lists.oasis-open.org> > >Sent: Thursday, May 27, 2004 11:28 AM > >Subject: [ws-caf] Mt Everest and WS-CF > > > >Hi Mark, > > > >You pointed the list at an interesting document by Savas et al. I > >commented upon it, as did Peter upon the interop demo, because it > >illustrates a fundamental issue for any potential user of > WS-CAF: what > >is the worth of WS-Context context-by-value? > > > >The argument for this feature seems to resemble the motivation for > >climbing Mt Everest: "because it's there". > > > >I don't think that this question can be circumvented, and it is > >relevant to WS-CF. Should WS-CF have a necessary dependency on > >WS-Context? After all, WS-Coordination manages to create a generic > >tree-building > >(address-exchange) protocol without use of a layer like WS-Context. I > >think this is a better model. Then those who wish to wrap context > >information in standard wrappers can do so (use WS-Context), > and those > >who don't wish to do so, don't need to (ignore WS-Context as adding > >little real value). > > > >My interest in this is far from academic. If WS-CAF transaction or > >coordination protocols gain traction at some future date, > then I would > >like to make our engineers' lives as easy as possible, by > streamlining > >the work needed to the strictly necessary (after all, it > will only be > >the third set of two-phase outcome protocols we have to add to our > >product, in order to accommodate the jostling of the > software industry > >majors). I cannot see how WS-Context contributes to WS-CF or WS-TXM. > > > >Incidentally, I made no mention of context by reference. I > view this as > >an interesting possibility fraught with problems, which I > predict will > >not be widely used. Every example of WS-Context use that I see > >discussed uses "by value". I certainly think that coordination > >protocols need by-value contexts (which of course can be carried in > >SOAP headers directly). > > > >Alastair > > > >-----Original Message----- > >From: Mark Little [mailto:mark.little@arjuna.com] > >Sent: 27 May 2004 10:20 > >To: Green, Alastair J.; ws-caf > >Subject: Re: [ws-caf] interesting document > > > >Alastair, is this interesting for a purely academic standpoint? I > >believe that the TC already discussed these issues and voted > on them, > >so it seems like going back over old stuff to me. To summarise what > >this TC already agreed on, since we neither mandate context-by-value > >nor context-by-reference in the base-line context document, > it is up to > >referencing specifications to determine which format they > wish to use. > >I think that arguing this again is not going to be fruitful and I'd > >like to see this TC move on to the coordination specification (which > >was agreed at New Orleans). > > > >Mark. > > > >---- > >Mark Little, > >Chief Architect, Transactions, > >Arjuna Technologies Ltd. > > > >www.arjuna.com > >----- Original Message ----- > >From: Green, Alastair J. <mailto:Alastair.Green@choreology.com> > >To: Mark <mailto:mark.little@arjuna.com> Little ; ws-caf > ><mailto:ws-caf@lists.oasis-open.org> > >Sent: Wednesday, May 26, 2004 6:03 PM > >Subject: RE: [ws-caf] interesting document > > > >I have to believe I'm missing something or being plain > stupid, but here > >goes ... > > > >It would be interesting, in light of Peter's recent mail on > the value > >of WS-Context context-by-value, to examine what would change > in these > >scenarios if the <ctx:context/> were to be replaced by a simple SOAP > >header element. Strip out <ctx:context/>, replace the placeholder > >"context state" with <protocol:context/>, place this element in the > >SOAP header, and proceed. This would be a less restrictive, but I > >believe legal, use of WS-I (i.e. move protocol-specific context info > >from body to header). > > > >It would also be interesting to consider, in the light of > Jim and Guy's > >exchanges, what role activity completion plays, if any? Activity > >completion can only be communicated to context recipients if > they are > >registered with the context service that knows that the > activity is now > >complete. WS-Context does not define such a > registration-notification > >mechanism. This continues to leave in question the > independent value of > >WS-Context context-by-value. This type of functionality must > reside in > >the surrounding protocol (session, coordination etc) that in > my example > >is denoted by the namespace URI indicated by the prefix > "protocol" (the > >"referencing specification"). An example of such a protocol > is WS-CF, > >or in truncated form, WS-Coordination. > > > >As there is no bundle of contexts specified by WS-Context (if my > >understanding has kept pace with the spec changes), the > argument that > >value is provided by easing interception (simpler to > identify the group > >of contexts that must be processed by a set of > interceptors), becomes a > >non-argument. > > > >Where does this leave the independent value of WS-Context > >context-by-value? > > > >These points are orthogonal to the issue: header element in the raw, > >body element in the raw, or element embedded in an address. > > > >Alastair > >-----Original Message----- > >From: Mark Little [mailto:mark.little@arjuna.com] > >Sent: 26 May 2004 16:45 > >To: ws-caf > >Subject: [ws-caf] interesting document > >http://forge.gridforum.org/projects/dais-wg/document/draft-gg f-dais-map >p >ings-ggf11/en/1 > >And Savas is a member of this TC (though I don't think he's ever >attended any of the teleconferences ;-) > >Mark. > >---- >Mark Little, >Chief Architect, Transactions, >Arjuna Technologies Ltd. > >www.arjuna.com > > >
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