Re: [ws-dd] Re: WS-DD comments on WS-Eventing WD-ws-eventing-20090924

As described by Antoine, two approaches can provide the linkage between
the port types of event source wsdl and notification wsdl. Regardless
the approach taken, we think the following issues have to be addressed.

1) one-way or two-way links
We think one-way link is sufficient since two-way links are more
difficult to maintain.

2) direction of the links
Both i) source -> notification and ii) notification -> source links can
represent m-n relations. We think direction i) is more inline with the
model in appendix A where the subscriber knows the event source first.

3) no event source port type
It is possible that the event source wsdl has no port type because i) it
has no operations other than ws-e; and ii) ws-e is implicit. In this
case, the event source wsdl has no port types.
If this happens, we may use a dummy empty port type in the event source
wsdl. For example, a wsdl extension approach may look like:

<portType name="xyz" eventTypes="list of URL" />

The advantage of this approach is that the links exist only between port
types and we avoid the complexity arising from cross-linking ports and
port types as proposed in [2].

4) problem with wsdl import
To import notification wsdl into event source wsdl (or vice visa) could
be problematic for code generation by some tools. If the tools cannot
distinguish regular operations from those representing event types, as
they both are inbound, they may generate incorrect and unnecessary code.
Typically, an event source implementation should generate server side
code from the event source wsdl and client side code from the
notification wsdl. If the two wsdl are merged through import, only one
type of code will be generated.

To address this issue, we should not import the wsdl files. Instead, the
attributes or the policy assertions should indicate the URL of the wsdl.

One way to achieve this using policy is proposed in [2][3]. An example
to use plain URL to locate the port type in a wsdl is:

eventType="http://wwww.example.com/myservice.wsdl#port-type-name"

[1] http://www.w3.org/Bugs/Public/show_bug.cgi?id=8198
[2]
http://lists.w3.org/Archives/Public/public-ws-resource-access/2009Aug/at
t-0012/NotificationWSDL_for_6401-6661_v4_submit.htm
[3]
http://lists.w3.org/Archives/Public/public-ws-resource-access/2009Aug/00
12.html


Li

Received on Tuesday, 26 January 2010 16:34:15 UTC