Checking if a variable exists in DMN / JUEL

BPMN & Modeling Discussion & Questions
1

Hi!

Is it possible to check if a variable is available in JUEL expressions?

I tried empty myVar, but this also fails if the variable is not declared in the scope (I guess there is a difference between a variable explicitly set to null and one not declared at all).

I stumbled upon this having a boolean output variable that is not set under some conditions. When I use this output as required input for another decision, it fails.

Is there a way to check this with JUEL? Or alternatively with groovy/JS?

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2

you can use the javascript text using ‘empty’ in the input expression and in the input values you can use boolean checks to evaluate the given condition.2019-03-05_15h46_15

3

Can you give me an example of how what to actually put into the input field? I’m only getting errors with these checks.

Also, somehow this seems like a bug that variables that are not set do not evaluate to null, but produce an error. Is this intentional?

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4

Yes I am also wondering the same thing…

It’s OK if it’s intentional. The problem is Camunda documentation is silent about this.

5

Same here, not seem to work in DMN input expression. Have tried a few permutations and combinations

6

An example would definitely help.

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