list.beforeFetchingNextBatch();
BasicDBObject query = new BasicDBObject();
query.put("_id", new BasicDBObject("$in", keysToLookup));
BasicDBObject orderBy = new BasicDBObject();
orderBy.put("_id", 1);
cursor = dbCollection.find(query).sort(orderBy).batchSize(batchSize);
if (list != null)
list.afterFetchingNextBatch(cursor.count());
} else {
cursor = new DBCursor(dbCollection, null, null, null);
}