My email for Greg and my AI [Fwd: Our AI on Anish's WS-Context comment#18]

[Doug Bunting <Doug.Bunting@Sun.COM>]

sorry for the delay...

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• From: Doug Bunting <Doug.Bunting@Sun.COM>
• To: Greg Pavlik <greg.pavlik@oracle.com>
• Date: Wed, 16 Feb 2005 13:02:12 -0800

Greg,

In an attempt to get to a single approach prior to sending something out to 
the TC list, I outline two possibilities below.  Let me know what you think.

Anish said:
"
18) Page 7, para right below figure 4 says:
"A service that requires a service reference
element MUST use the mustUnderstand attribute for the SOAP header
element within which it is enclosed and MUST return a mustUnderstand
SOAP fault if the reference element isn’t present and understood."

I don't understand what this means. How does MU header help here?
"

My comment during the call was that it appeared the first MUST was a client 
requirement and the second a service requirement.

Someone else asked if these requirements belonged in WS-Context at all.  I 
assume their point was the addressing specification (or, possibly, a 
referencing specification) would decide when and where mustUnderstand was 
useful or required.

In context (pun intended), things get a bit more confusing:
"
Messages sent to referenced services MUST use the addressing scheme defined 
by the specification indicated by the value of the reference-scheme element 
if present. Otherwise, the namespace URI associated with the Web service 
reference element MUST be used to determine the required addressing scheme. 
  A service that requires a service reference element MUST use the 
mustUnderstand attribute for the SOAP header element within which it is 
enclosed and MUST return a mustUnderstand SOAP fault if the reference 
element isn’t present and understood.
"

Just translating this into active voice and correcting to match the schema 
might help:
"
If present, the value of the reference-scheme attribute indicates the 
specification defining the addressing scheme in use for this reference. 
Otherwise, the namespace URI associated with the immediate descendant of 
the element of type ServiceRefType provides this indication.  A sender MUST 
use the identified addressing scheme when sending messages to the 
referenced address.

The reference itself MAY be required in some messages.  In this case, 
message sender MUST use the SOAP mustUnderstand attribute on the header 
containing the required reference.  A service receiving such a message MUST 
return a mustUnderstand SOAP fault if the reference is not present and 
understood.
"

Another alternative may be simply removing this entire paragraph.  It seems 
redundant with material earlier.  For example, have a look at the paragraph 
below figure 2.

thanx,
	doug

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