@SuppressWarnings("unchecked")
	@Override
	public T rowToObjec(ResultSet rs) throws SQLException {

assert(rs.getMetaData().getColumnCount() == 1);

		T o = (T) JdbcUtil.getResultSetValue(rs, 1, type);
		if (o != null && type.isInstance(o)) {
			return o;
		} else {
			throw new RuntimeException(
					"failed to get requested value: type mismatch");
		}
	}