Use numeric, string, or Boolean expressions when configuring an event source, to determine whether the event is emitted.
xpath-query relational-operator value
$Body/StockTrade[1]/Details[1]/Value[1] > 10000
The
[1] suffixes in the query specify that the first occurrence of the
element within its parent is required. If these suffixes are not
specified, the XPath engine searches the message for other occurrences
of each element. This search might adversely affect performance. $Body/StockTrade[1]/Details[1]/Company[1] = 'Stock Co'
$Body/StockTrade[1]/Shares[1]/Transfer[1]/Approved[1] = 'true'
XPath queries that return a nodeset, such as $Body/StockTrade[1]/Details[1], are always evaluated as false, because they cannot be converted to a Boolean value.