Check for 'null' doesn't work

[Former Community Member]

Hello!



We've experienced a problem in Workbench regarding Boolean functions within XPath expressions. We aren't able to check whether a variable is null or not. An example:



>Process variable name:

b xy



>Process variable type:

b String



>Process variable value:

b null



>Xpath evaluation:

b is-null(/process_data/@xy) = true()



>Result:

b the Xpath evaluation returns false!!



Does anybody see the problem?

Thanks,

Nico

[Former Community Member]

We could find the reason for this problem:



Accessing a process variable using XPath does never return 'null' as value! Assuming the variable xy is 'null' the following XPath statement returns an empty string (""):



> /process_data/@xy



Therefore: use the following Xpath statement to check a string variable for null:



> /process_data/@xy = ""



The is-null() function doens't work for string variables.



Regards,

Nico

[Zvranic]

Doesn't work for document variables too!

/process_data/@document = "" also works..

I know it's a 2 year old thread, but it's still a problem in ES2!

[Former Community Member]

In my experience the is-null function works for SetValue but not for route conditions. Not sure why. I realize this is an old post, but I just came across it.

-Nissan

[Former Community Member]

point taken,will look into it and see if we can enhance it for future release

thanks