Node, State, and ProcessState don't provide any preliminary check for conditions provided on transitions. No check is performed until the transition is signaled, at which point the process will barf if a condition is present on the default transition, and that condition evaluates to false.

Regardless if a person "should" be using transition conditions in Node or State, the schema allows it, the documentation doesn't forbid it, and the current behavior of a Transition element in the jpdl is inconsistent. The fix to make everything consistent is fairly simple--only org.jbpm.graph.def.Node needs to really be altered (and a one-liner in ProcessState):

In org.jbpm.graph.def.Node, add the following method:

// BRITT--
public Transition calculateLeavingTransition(ExecutionContext executionContext) {
Transition transition = null;
Iterator iter = leavingTransitions.iterator();
while (iter.hasNext()) {
Transition candidate = (Transition) iter.next();

String conditionExpression = candidate.getCondition();
if (conditionExpression != null) {
Object result = JbpmExpressionEvaluator.evaluate(conditionExpression, executionContext);
if (Boolean.TRUE.equals(result))

{ transition = candidate; break; }

} else

{ transition = candidate; break; }

}
if (transition == null)

{ log.warn("All transition conditions have evaluated to 'false'. Returning the default transition, prepped for signalling (condition enforcement has been removed)."); this.getDefaultLeavingTransition().removeConditionEnforcement(); transition = this.getDefaultLeavingTransition(); }

return transition;
}
// --BRITT

...and modify "leave(ExecutionContext executionContext)":

// BRITT --replace the following line with the code below
// to check conditions before selecting the transition to take...

//leave(executionContext, getDefaultLeavingTransition()); //original line
leave(executionContext, calculateLeavingTransition(executionContext));
// --BRITT

For consistency, ProcessState should also have one line modified at the very end of it's "leave(ExecutionContext, Transition)" method:

// BRITT-- rather than specify which transition, let the super class decide...
//super.leave(executionContext, getDefaultLeavingTransition());
super.leave(executionContext, calculateLeavingTransition(executionContext));
// --BRITT