Re: [wsn] Identifying WS-BaseNotification dependencies on WSRF

[David Hull <dmh@tibco.com>]

One note on Precondition and Selector:

>Section 4.2: The Subscribe message has 2 fields of type QueryExpression
>as defined in WSRF-RP. The fields are Precondition and Selector. It is
>not clear that these fields have the same type of expression as the
>operation QueryResourceProperties defined in WSRF-RP. There is a
>statement that the Subscribe message must follow the implied resource
>pattern.
>  
>
The WSRP spec just says that a QueryExpression looks like

	<wsrp:QueryExpression dialect="someURI">
		{any}
	</wsrp:QueryExpression>

The dialect, content and semantics are completely extensible.  This is 
fine, but as far as I can tell, WSRP is simply defining an element name 
and an attribute.  It seems more direct just to say

	<wsnt:Precondition dialect="someURI">
		{any}
	</wsnt:Precondition>

and similarly for Selector.  This would bring these two in line with 
TopicExpression and spare the reader from chasing the link to WSRP.