code: private DBObject createQueryPartition(MongoPartition partition) {
  
          QueryBuilder queryBuilderMin = QueryBuilder.start(partition.getKey());
          DBObject bsonObjectMin = queryBuilderMin.greaterThanEquals(partition.splitWrapper().getStartToken()).get();
  
          QueryBuilder queryBuilderMax = QueryBuilder.start(partition.getKey());
          DBObject bsonObjectMax = queryBuilderMax.lessThan(partition.splitWrapper().getEndToken()).get();
  
          QueryBuilder queryBuilder = QueryBuilder.start();
          if (partition.splitWrapper().getStartToken() != null) {
              queryBuilder.and(bsonObjectMin);
          }
  
          if (partition.splitWrapper().getEndToken() != null) {
              queryBuilder.and(bsonObjectMax);
          }
  
          LOG.debug("mongodb query "+queryBuilder.get());
  
          return queryBuilder.get();
      }
docs: Create query partition.
  
  @param partition the partition
  @return the dB object