code: public List<T> list(List<Long> ids)
      {
          List<T> ret = new ArrayList<T>();
  
          if(ids != null)
          {
              for(Long id : ids)
              {
                  T resource = get(id);
                  if(resource != null)
                      ret.add(resource);
              }
          }
  
          return ret;
      }
docs: Returns the resources that match the given ids.
  @param ids The list of the resource ids
  @return The resources that match the given ids