RE: [wsbpel] Issue - 77 - Under specified operation definitions

+1. Very clearly articulated. -Edwin

From: Ron Ten-Hove [mailto:Ronald.Ten-Hove@Sun.COM]
Sent: Monday, November 24, 2003 7:13 PM
To: Ugo Corda
Cc: wsbpel@lists.oasis-open.org
Subject: Re: [wsbpel] Issue - 77 - Under specified operation definitions

Ugo,

Ugo Corda wrote:

No, I disagree - the abstract interface of a service is ONLY

defined by its portType(s).

From WSDL 1.1, Section 2.5: Bindings:

"A binding defines message format and protocol details for operations and messages defined by a particular portType. There may be any number of bindings for a given portType."

Bindings have a very clear relationship with port types. Port types are defined in part as (section 2.4):

"A port type is a named set of abstract operations and the abstract messages involved."

Our operations (the abstract service being offered) are based only the information contained in the port type.

    It is true that bindings (e.g., SOAP) allow extra message parts to be utilized by the binding. However, there is clearly no connection between these extra message parts and the operations offered by our abstract service.

    I will try putting this a different way. Multiple bindings are allowed for a single port type. Some bindings will include extra message parts (possibly as SOAP headers, or JMS headers), while others will not (perhaps an EJB or MDB binding?). The only message parts guaranteed to be delivered to the service by all of the possible bindings are those declared in the port type.
    How could any reasonable interpretation or use of WSDL conclude that a specific binding type (namely SOAP) has the ability to jump across the logical layers that WSDL has defined (albeit imperfectly!). This is fundamental: we are talking about the WSDL model of messaging, not SOAP. If people confuse WSDL for SOAP we should gently correct them, or, if too late, provide workarounds to some of their architecturally-challenged creations (as Satish has very reasonably suggested). We shouldn't give up on the basics of WS architecture!

-Ron

 
    

Yes, I understand your position. My point is that it is just your personal position, not supported by anything said in the spec. You cannot expect designers to base their choices on anything outside the spec, no matter how reasonable those external argumentations are. That's one of the rules of the standards game ...

Ugo

-----Original Message-----

From: Sanjiva Weerawarana [mailto:sanjiva@watson.ibm.com]

Sent: Monday, November 24, 2003 10:51 AM

To: Ugo Corda; Satish Thatte; Francisco Curbera

Cc: Ron Ten-Hove; wsbpel@lists.oasis-open.org

Subject: Re: [wsbpel] Issue - 77 - Under specified operation

definitions

OK this is my last note on this topic ..

"Ugo Corda" <UCorda@SeeBeyond.com> writes:

I would say that the abstract behavior of a Web service is

defined by its abstract interface. The portType is just a

subset of the WSDL 1.1 abstract interface, because abstract

messages are allowed in the abstract interface that are not

part of a portType.

No, I disagree - the abstract interface of a service is ONLY

defined by its portType(s).

(Don't blame me for that: your name is on

the WSDL 1.1 spec, not mine ;-).

I'll accept blame if it was written incorrectly, but see below.

Let me quote here WSDL 1.1, sec. 2.3.2, Abstract vs.

Concrete Messages:

"Message definitions are always considered to be an abstract

definition of the message content. A message binding describes

how the abstract content is mapped into a concrete format. However,

in some cases, the abstract definition may match the concrete

representation very closely or exactly for one or more bindings,

so those binding(s) will supply little or no mapping information.

However, another binding of the same message definition may require

extensive mapping information. For this reason, it is not until the

binding is inspected that one can determine "how abstract" the

message really is".

Everything above is true - but its *only* talking about abstract

message definitions and how they are bound to the "wire." It does

not say *anything* about what constitutes the abstract interface of

a service.

So, I will stick to my position that the interface of a service

is defined by its portType(s) and thus BPEL should only allow

access to the messages as brought in by the portType.

It seems like its time to agree to disagree ...

Sanjiva.

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