Manually execute expression

Let’s take a simple example: on a sequence flow after an exclusive gateway, I use an expression, lets say `"${myService.isFoo(execution)}". It calls a service (typically spring or cdi bean) and returns a boolean.

Now let’s assume I have a Listener or Delegate that operates on an execution. How can I execute the above expression manually? Pseudo code:

public void notify(DelegateExecution e) {
   boolean value =  e....getExpressionManager().execute("${myService.isFoo(execution)"}
   ...
}

Is where a way to do so? I have a use case where I want to configure conditions as expressions and execute them dynamically based on (for example) the currentActivity).