Re: [wsbpel] policy annotations and BPEL (was RE: [wsbpel] Issue - 66- Zero or multiple matches of correlation set)

Ron,

 

Clearly, the disagreement is not about the need for QoS and other policy annotation. There are two separate issues we are talking about.

 

A.	Does such annotation belong within BPEL?
B.	Whether it does or not, how should it be expressed?

 

The following are my personal opinions.  I won't qualify them as such at every step.

 

I believe such annotation is not within the scope of the TC's work.  BPEL is not attempting to provide a complete business process modeling solution.  What it is attempting to standardize is the description of long-running patterns of service-level messaging interactions both for multi-party business protocol definition and multi-service composition.  If we attempt to go beyond this, we will either do an incomplete and half-baked job of policy annotation or we will not finish for a very long time.

 

Regardless of this, we have two options for expressing annotations.  Use BPEL's extensibility mechanisms and express them as BPEL extensions.  Or follow a separate policy annotation model that is used not only in the context of BPEL but in most other contexts.  Let us take the example of security annotations for messaging interactions.  We may sometimes need to annotate a specific receive action in a BPEL process, sometimes an input action within a WSDL operation, or sometimes an entire WSDL portType.  The annotation may be essentially the same: e.g., message(s) must be signed.  If we have BPEL specific extensions for this and WSDL has WSDL specific extensions for the same sort of annotation, we now have two ways of saying the same thing, which will inevitably start diverging at least in subtle ways simply because there are many ways to express this sort of constraint and reasonable groups of people will come up with different styles of annotation which are not isomorphic.  


 

This is why I favor the idea of a separate policy annotation model that is used not only in the context of BPEL but in most other contexts.  We then have a chance to provide uniform annotation at all the levels we need to, without having to anticipate every combination of possibilities.  Yes, WS-Policy is such a model but the point I am making is that we need something of that sort.  I am not asking us to take a dependency on WS-Policy specifically.

 

Satish


________________________________

From: Ron Ten-Hove [mailto:]
Sent: Fri 9/26/2003 1:03 PM
To: Satish Thatte
Cc: 
Subject: Re: [wsbpel] Issue - 66 - Zero or multiple matches of correlation set



Satish Thatte wrote: