User-defined XPath functions

User-defined XML Path Language (XPath) functions can be made available to the monitor model. You can use these functions anywhere that you can use an XPath expression in the model, such as in filter expressions, correlation expressions, and metric value expressions.

For example, you might use a user-defined function in a recurring wait-time trigger, where you poll at regular intervals and send an outbound event if the value crosses a predefined threshold. A user-defined function can obtain sensitive data that you do not want to send in events, such as an employee's salary. If the event carries the employee's ID, you can use a user-defined function to get the salary from a secure web service or from a database and store it in a metric.

All available user-defined XPath functions are shown in a tree (for reference) on the Monitor Details Model page. When you create an expression, the user-defined functions are shown in content assist along with the built-in functions.