code: @SuppressWarnings("unchecked")
      public DataMapper<Object, DBObject> getDataMapper(Class<?> domainObjectClass) {
          if (additionalDataMappers != null) {
              for (DataMapper<Object, DBObject> each : additionalDataMappers) {
                  if (each.canMapToData(domainObjectClass)) {
                      return each;
                  }
              }
          }
          if (dataMapper.canMapToData(domainObjectClass)) {
              return (DataMapper<Object, DBObject>) dataMapper;
          }
          // no matching
          return null;
      }
docs: Matching DataMapper, if any, otherwise null