public void close() {
		try {
			if (rs != null) {
				rs.close();
				rs = null;
			}
			if (ps != null) {
				ps.close();
				ps = null;
			}
			if (connection != null) {
				connection.close();
				connection = null;
			}
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		} 
	}