How to remove variable from process

[mnorsic]

Hi All,

is there a way to remove variable from process instance?

Right now, we have a method

processInstance.setVariable("variable", value);

Beside the obvious solution

processInstance.setVariable("variable", null);

are there any other solutions?

For example, it would be nice to have something like this:

processInstance.removeVariable("variable");

Does it make sense?

Thanks,

Miljenko

[tsurdilovic]

Setting it to null is fine. Your process variable could be used in many other places in the process, for example data input/output associations, expressions etc. Removing it would mean a possibly cascating effect which could cause runtime issues. Could add a convenience method that set it to null as you are doing now but I would not call it "removeVariable".

Hope this helps.

[mnorsic]

Hi Tihomir,

that makes sense, of course. I don't think we need a separate method for that, it's just that I wanted to know what's the best practice, because I'd like to control variable lifecyle.

For example, Drools has a different logic for that, where I can insert and retract an object from a knowledge session, so I thought can I use this mechanism in a workflow process scenario, for example to trigger some event when a variable is removed from a process instance.

Thanks,

Miljenko

[tsurdilovic]

You should be able to use rule constraints to accomplish this behaviour.

[mnorsic]

Hi Tihomir,

thanks for the tip, I can use rule task to retract variable from knowledge session, as well as for reset process instance variable.

Miljenko