MongoDB Java Driver Infinite loop while reading results

Question

I am reading MongoDB results using the following code , however the while loop runs in an infinite loop always iterating over the first element in the collection, can someone point out what I am doing wrong.

       Iterable<DBObject> list = playerData.results();
        if(list != null){
            while(list.iterator().hasNext()) {

                DBObject obj = list.iterator().next();
                DBObject id =  (DBObject) obj.get("_id");
                String player= obj.get("player").toString();
                //Populate the memcached here .
                PlayerDTO rcd = new PlayerDTO();

                if(id != null && id.get("venue" != null && id.get("score") != null) {

                    rcd.setVenue(id.get("venue").toString());
                    rcd.setScore(new Double(id.get("score").toString()).doubleValue());
                }

            }
        }

Rick Mangi · Accepted Answer · 2013-07-12 19:54:59Z

2

You are reassigning the original iterator to the while() loop each iteration through.

Iterator i = list.iterator();
while(i.hasNext()) {
  ....
}

answered Jul 12, 2013 at 19:54

Rick Mangi

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4 Comments

Marsellus Wallace Over a year ago

Or a nicer for ( DBObject obj : list ) { do_stuff_with_obj }

Rick Mangi Over a year ago

indeed. that is the cleaner way.

user1965449 Over a year ago

Thanks, but I am surpised to know that list.iterator() returns a new iterator everytime!

Rick Mangi Over a year ago

Why? I think it's pretty obvious. What if you want to iterate twice?

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