@Override
public void start() {
for (Expression context : expression.contexts) {
Object result = event.evaluate(context);
if (result == null) {
Object eval = event.result(context);
if (eval instanceof LocationEvaluation) ((LocationEvaluation) eval).nodeSetListener = this;
else ((PathEvaluation) eval).nodeSetListener = this;
} else throw new NotImplementedException();
}
}
@Override
public Object getResult(Event event) {
PathEvaluation pathEvaluation = (PathEvaluation) event.result(pathExpression);
return pathEvaluation.evaluations.get(event.order());
}