code: protected <T> int update (final Table<T> table, final T object,
                                final FieldMask mask)
          throws PersistenceException
      {
          return executeUpdate(new Operation<Integer>() {
              public Integer invoke (Connection conn, DatabaseLiaison liaison)
                  throws SQLException, PersistenceException
              {
                  return table.update(conn, object, mask);
              }
          });
      }
docs: Updates fields specified by the supplied field mask in the supplied
  object in the specified table.
  
  @return the number of rows modified by the update.