Designer 10.7 | webMethods Service Development Help | Conditional Expressions | Syntax | Verifying Variable Existence
 
Verifying Variable Existence
Sometimes you might want to create an expression that checks only for the existence of a variable in the pipeline or checks to see whether a variable is null. The following table describes the syntax used to check the pipeline for variable existence.
To check if...
Use this syntax...
Description
Variable exists
variableName
Evaluates to true if the specified variable exists in the pipeline and has a non-null value.
Variable does not exist
!variableName
Evaluates to true if the specified variable does not exist in the pipeline or is null.
Related Topics
Addressing Variables