public static Map<String, List<String>> queryString(DataMap dataMap){
    Map<String, List<String>> result = new HashMap<>();
    DataMap processedDataMap = processProjections(dataMap, result);
    iterate("", processedDataMap, result);
    return result;
  }
@Test
  /**
   * Test query string representation of a DataMap representing a compound key
   */
  public void testCompoundKeyDataMapQueryString() throws Exception
  {
    DataMap dataMap = new DataMap();
    dataMap.put("memberID", 2);
    dataMap.put("groupID", 1);

    Map<String, List<String>> result = QueryParamsDataMap.queryString(dataMap);
    Assert.assertEquals("2", result.get("memberID").get(0));
    Assert.assertEquals("1", result.get("groupID").get(0));
  }