code: protected T get(Connection conn, BoId id) {
          if (id == null || id.values == null || id.values.length == 0) {
              return null;
          }
          final String cacheKey = cacheKey(id);
          T bo = getFromCache(getCacheName(), cacheKey, typeClass);
          if (bo == null) {
              bo = executeSelectOne(rowMapper, conn, calcSqlSelectOne(id), id.values);
              putToCache(getCacheName(), cacheKey, bo);
          }
          return bo;
      }
docs: Fetch an existing BO from storage by id.
  
  @param conn
  @param id
  @return