%dw 2.0 import * from dw::Runtime var result =  output application/json --- if(sizeOf(result) <= 0) fail('Data was empty') else result
Throws an exception with the specified message.
This example returns a failure message
Data was empty because the expression
(sizeOf(myVar) <= 0) is
true. A shortened version of the error message
is shown in the Output section below.