Issue - 110 - Issues with the Pattern Attribute

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Issue - 110 - Issues with the Pattern Attribute
Status: open

Area: Syntax and validation

Date added: 24 Mar 2004

Submitter: Yaron Y. Goland

Date submitted: 24 March 2004

Description: Section 10.2 of the specification currently says:

Finally, in the case of invoke, when the operation invoked is 
synchronous request/response, a pattern attribute is used to indicate 
whether the correlation applies to the outbound (request) message, the 
inbound (response) message, or both. These ideas are explained in more 
detail in the context of the use of correlation in the rest of this 
example.

There are several issues this text raises about the pattern attribute: 

The pattern attribute is intended to deal with request/response 
patterns but such patterns are not required to be synchronous. It is 
legal in WSDL 1.1 to define a request/response operation that bind to an 
asynchronous binding. I realize that the intent was probably to say that 
the behavior within BPEL (as opposed to on the wire) is synchronous but 
in that case the distinction needs to be made clear.

I consistently get confused about what in versus out means. Why not 
use names that more closely match the WSDL names? E.g. something like 
"request | response | both"? I would extend this change to the 
inputvariable and outputvariable attributes renaming them 
responseVariable and requestVariable.

The text in the referenced paragraph has caused confusion because 
it implies that the pattern attribute is only needed on correlation sets 
on request/response invokes. But we also require its use on one-ways. 
Ideally we would make the pattern attribute illegal on correlation sets 
defined on one-way Invokes and mandatory on correlation sets used on 
request/response Invokes. I realize that we probably can't express that 
restriction in XML Schema but, if so, we shouldn't allow XML Schema's 
limitations stop us from doing the right thing for our users.

Changes: 24 Mar 2004 - new issue

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