Does MVEL or Drools cannot resolve fact that its type is Map<String,List<Object>>?

Question

my rules are just like this:

   rule "calcitonin evaluation"
     lock-on-active true
     salience 0
   when
     $p : Patient($labtestItem : labtests.get("calcitonin").get("0"))
     LabTestItem($result : result.substring(1,(result.length)-1), parseFloat($result) > 8.4) from $labtestItem
   then
     $labtestItem.setAbnormalIndicator("high");
     $labtestItem.setAttentionLevel("important");
     modify($p){}
   end

but it always built with error:

Unable to Analyse Expression labtests.get("calcitonin").get(0):
sun.reflect.generics.reflectiveObjects.ParameterizedTypeImpl cannot be cast to java.lang.Class

if i write my rules like this,it runs:

   rule "calcitonin evaluation"
     lock-on-active true
     salience 0
   when
     $p : Patient($labtestItem : labtests)
   then
     System.out.println($labtestItem.get("calcitonin"));
     modify($p){}
   end

Answer 1

The .get("0") doesn't make sense - List.get expects an integer. But this won't make the problem go away. You need a boolean expression if it isn't a simple binding.

I'd write the rule like this:

rule "calcitonin evaluation"
when
  $p : Patient($labtestItem : labtests)
  $lti: LabTestItem($result : result, parseFloat($result.substring(1,(result.length)-1)) > 8.4) from $labtestItem.get("calcitonin").get(0)
then
  $lti.setAbnormalIndicator("high");
  $lti.setAttentionLevel("important");
  modify($p){}
end

Edit: To avoid a null result of $labtestItem.get("calcitonin"), add the guard as a constraint:

   $p : Patient($labtestItem : labtests, 
                labtests.get("calcitonin") != null)