Need help in parsing Group operation's results in Java

[ajay]

I could not find Aggregation Group support in Morphia. So I am trying to use base Java driver for it. I think I got it working. But I need help in walking/parsing the results. How do you parse/walk the DBObject that is the result of group operation below?

   DBObject dbobj = col.group(key, cond, initial, "function (obj, prev) {prev.count++;}");

With corresponding Mongo shell script, this output looks like

[

        {

                "managedEntityId" : ObjectId("5092ad290cf24adee7e8a77c"),

                "severity" : "info",

                "count" : 2

        },

        {

                "managedEntityId" : ObjectId("5092ad290cf24adee7e8a77c"),

                "severity" : "minor",

                "count" : 4

        }

]

If I figure it out, I will post my results here. But if somebody already knows the answer, it will save me time.

Ajay

[ajay]

With help from Java debugger, following works. Essentially groups returns a BasicDBList of DBObjects

BasicDBList dbList = (BasicDBList) col.group(key, cond, initial, "function (obj, prev) {prev.count++;}");

        for (Object obj : dbList) {

            DBObject dbobj = (DBObject) obj;

            for (String k: dbobj.keySet()) {

                Object o = dbobj.get(k);

            }

        }

Does it sound right?

[Stephen Lee]

ajay, this looks right to me.  Each document should be a nested collection of sub-documents as DBObject's or DBList's.