Evaluate juel expression outside of activiti engine

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hery1

Hi,

Is there a way to evaluate a juel expression with the value of variables of currently running process outside of the activiti engine?

For example, if I deploy a workflow that internally uses a variable called 'username' and then start an instance of it with the value of username = "hery".
Is there an API in the engine that I can use to evaluate the expression "Hello ${username}" to give me the string "Hello hery" separately from the engine?

From the user guide, I can only see that the way to evaluate a juel expression in the engine is to define the expression needed somewhere in the bpmn20 xml (either for service task, execution listener, task listener or conditional sequence flow).

Regards,
Hery

frederikherema1

You can just use JUEL itself for this. You can either use the JUEL in activiti (org.activiti….juel…) or JUEL jar itself.

Using the ExpressionFactory, you can create javax.el.ValueExpression object which you can evaluate agains any context (including non-activiti) by using an ELResolver. When using Juel, the ExpressionFactory will return JUEL for creating expressions (it's an SPI thingy).