RE: [wsbpel] Issue - 88 - Import Errata

[Francisco Curbera <curbera@us.ibm.com>]

Hi Ugo,

I think you have spotted an important difference in approach that had not
surfaced before.  I think this relates to whether we make imports required
or not - and what "honor" means.

Nothing in WSDL 1.1 says that imports are required (as they are for
instance in XSD). The only statement made in WSDL 1.1 is that import
"allows associating a namespace with a location". So the notion of
"honoring" import is a very vague one: if the association is not used
(because we cached the file or whatever) then the import is ignored, but
this does not mean that definitions from that namespace (or from namespaces
not imported) are not processed. External definitions are referenced using
qualified names, and XML namespace mechanisms are there to allow unique
identification - how they are found and retrieved is up to each processing
environment.  Import statements just make life a little easier by providing
an associated location.

XML Schema does require an import clause for every external namespace
containing definitions. Maybe it then makes more sense to talk about
"honoring" an import because a processor can rely on inspecting imports
clauses to preprocess all external definitions it depends on, instead of
relying on XML namespace mechanisms.

So I would say that there is a legitimate issue here, but that it goes
beyond the strict wording that you mention. I think we need  to address of
whether imports are required for every external definition used by the
process. I can imagine there will be different opinions.

Paco




                                                                                                                                        
                      "Ugo Corda"                                                                                                       
                      <UCorda@SeeBeyond        To:       <wsbpel@lists.oasis-open.org>                                                  
                      .com>                    cc:                                                                                      
                                               Subject:  RE: [wsbpel] Issue - 88 - Import Errata                                        
                      12/03/2003 07:08                                                                                                  
                      PM                                                                                                                
                                                                                                                                        




> What happens if an engine chooses not to honor the import?
> The current text of the BPEL spec states that the BPEL engine
> is not required to import the files it is pointed at.

 I don't think that not importing the files necessarily implies that the
import is not honored.

The original statement in the resolution of Issue 7 was:

"A <bpel:import> location element will be interpreted as a hint for BPEL
processors. In particular, processors are not required to retrieve the
imported document from the specified location".

So it only says that the location information is a hint (but the import
statement could still be satisfied by other means).

The statement appearing in the latest draft is more ambiguous:

"The presence of an <import> element should be interpreted as a hint to the
BPEL4WS processor. In particular, processors are not required to retrieve
the imported document from the location specified on the <import> element".

Now it is saying that the <import> element itself is a hint. Not sure what
exactly that means.

Ugo