Re: [wsrp-coord] V1.0 API vs. V2.0 API

[Rich Thompson <richt2@us.ibm.com>]

Avi,

I had put off responding to your question
until more of the active feature proposals had been incorporated into the
spec. I have nearly finished the set the TC has judged as ready to incorporate
and I would say that on a conceptual level the changes introduced by v2
are all optional extensions of v1 (with the possible exception of changing
the meaning of a missing CacheControl). That holds out hope that a v2 Consumer
could use a v1 Producer without significant special considerations as it
would just mean certain fields and functionality would be unavailable.

As I started looking at the next level
down recently, it became clear that the need to version the portTypes to
indicate whether or not the new things were supported (e.g. getResource)
would cause the Consumer to be sensitive to the difference between v1 and
v2 Producers on at least the communications level (If I remember correctly,
portType inheritance is slated for WSDL 2.0, but is unavailable in WSDL
1.2).

The next level lower revolves around
the standard mapping of namespaces to hierarchies that most tools do. We
have a choice of having the v2 schema be completely stand-alone (i.e. shared
items are simply cut&pasted to the new namespace) or have it import
the v1 schema and simply extend the types where additional fields are added.
The advantage of the former is that is it clear what one is dealing with
at all times (e.g. harder to get confused by the small difference between
the v1 & v2 ServiceDecriptions) as the packaging clearly says which
you have. The advantage of the second is that eliminates objects that differ
only by their packaging (e.g. ItemDescription). The second may also reduce
the effort for v1 implementations to add support for v2 as it is a minority
of things that are being extended.

As for the reverse direction, I would
not expect a v1 Consumer to even know to look for the v2 portTypes so unless
the Producer was gracious enough to offer both sets of interfaces, such
a Consumer would be unable to use the Producer. 

Rich

"Klein, Avi" <avi.klein@sap.com>

11/21/2004 09:14 AM

To	wsrp-coord@lists.oasis-open.org
cc
Subject	[wsrp-coord] V1.0 API vs. V2.0 API

Hi All,
 
How do we (if at all) intend to deal with
backwards compatibility between V2.0 and V1.0?
 
I other words, would is the expected behaviour
in the case where a 2.0 Consumer tries to interact with a 1.0 Producer
and vice versa?
 
 
Thanks,
Avi.

---

Avi Klein | iView Runtime Team | Portal Runtime | Portal Platform |
SAP Labs Israel | T: +972 9 7779489 | F: +972 9 7779985