title: Spring data Mongodb Group by with multi criteria - issues
body: <p>I want to group by particular column whose count is equal to some input number. </p>
  
  <p><strong>my query</strong>:</p>
  
  <pre><code>Criteria countCriteria = Criteria.where("count").is(2);
  
  if(!criteria.getCriteriaObject().keySet().isEmpty()){
      countCriteria.andOperator(criteria);
  }
  </code></pre>
  
  <p><strong>criteria</strong>: Criteria Object what I get as input</p>
  
  <pre><code>Aggregation aggregation = Aggregation.newAggregation(
      Aggregation.group(MBR_REWARD_ENROLL_NUM).count().as("count"),
      Aggregation.match(countCriteria)
  );
  </code></pre>
  
  <p>If I pass some Criteria to 'criteria' object, it is not working. If I don't pass anything, then it is working. Could somebody help me?</p>