[rules-users] Question about Drools accessing a global HashMap and comparing it to an object value

[mviens]

MyObj is a Java object that contains:

    String state;
    String code;
    public void addError(String message);

myObjList is an ArrayList<MyObj> containing from 2 to 20,000 objects

state2CodeMap is a HashMap<String, ArrayList<String>> containing an entry
for each US state. The associated ArrayList contains a minimum of 1 entry,
up to 200 entries.

I need to create a rule that checks all of the MyObj objects in myObjList,
gets the appropriate ArrayList from state2CodeMap based on myObj.state and
then if myObj.code not memberOf $codeList, run the "then" portion of the
rule.

I have created about 60 fairly simple rules, that are working just fine, but
this one is a little too complex for me to userstand how to write it in
Drools. Looking at this page (
http://blog.athico.com/2007/06/chained-from-accumulate-collect.html
http://blog.athico.com/2007/06/chained-from-accumulate-collect.html ), I can
see that nested "from" seems to be supported, but the page seems to be for
Drools 4. Plus, I have had to teach myself Drools in the past week. I could
really use some help with this. Any assistance is greatly appreciated!

Mike V.

    global List myObjList;
    global HashMap state2CodeMap;

    # this rule is working just fine!
    rule "Check for null State"
        when
            $objs : ArrayList() from collect(MyObj(state == null || state ==
"") from myObjList)
        then
            for (MyObj myObj : (ArrayList<MyObj>)$objs)
            {
                myObj.addError("State must have a value");
            }
    end

    # I really have no idea how to write this rule
    rule "Check for valid code"
        when
            $objs : ArrayList() from collect(MyObj())
        then
            for (MyObj myObj : (ArrayList<MyObj>)$objs)
            {
                myObj.addError("Code is not valid for the State");
            }
    end

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