HP e-CommerceXML Accelerator sa7150 - Manual (Page 30)

C H A P T E R 3 HP e-Commerce/XML Server Accelerator SA7150 User Guide
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Negation Operator
The “*” and “!” operators are allowed in URI expressions, but they
can exist only at the beginning or end of an expression. Also, a
positive expression must appear after a not (!) expression, otherwise
the (!) expression has no effect.
The order of URI expressions is significant only when the “not” (!)
operator is used.
Operators
NOTE: The SA7150 uses
a subset of the XPath
Language standard. XML expressions consist of sequences of one or more XML elements
or attributes combined with various “operators.” “Step operators” tell
the SA7150 where in the XML data tree to look, while “comparison
operators” tell the SA7150 what to look for. In typical XML
expressions, elements are separated by step operators—single or
double slashes (/ or //). These are used to select elements according to
their location (“node”) in the XML data tree. Step operators are
described in the table above. Comparison operators are the familiar
“equal to,” “not equal to,” “greater than,” “less than,”and other such
symbols. These form the bases upon which the SA7150 compares
incoming XML data to its own XML patterns to decide where to send
each XML document for fulfillment.
Expression Yields
!*.asp All non-ASP requests
!*/PurchaseOrder All non-PurchaseOrder requests
!/Buy.cgi All non-Buy.cgi requests
Use of the Negation Operator