/**
  * Method that edits a class from a database
  *
  * @author Ognjen Mišiæ
  * @param ca Class attendance we want to edit
  * @param classID we identify the class attendance by class id parameter
  * @throws ParseException
  * @throws SQLException
  */
 public static void editClass(ClassAttendance ca, int classID)
     throws ParseException, SQLException {
   try {
     conn = connectToDb();
     stmnt = createReadOnlyStatement(conn);
     rs = stmnt.executeQuery(SELECT_ALL_FROM_CLASSES_ATTENDANCE);
     String sql =
         "UPDATE classes_attendance SET class_description='"
             + ca.getClassDescription()
             + "', date='"
             + ca.getDate()
             + "', duration='"
             + ca.getDuration()
             + "' WHERE class_id='"
             + classID
             + "';";
     while (rs.next()) {
       if (rs.getInt("class_id") == ca.getClassID()) {
         Statement stmnt2 = createUpdateableStatement(conn);
         if (ca.getClassDescription().length() < 2) {
           setErrorMessage("Invalid class description");
           break;
         } else if (!isValidDate(ca.getDate())) {
           setErrorMessage("Invalid date.");
           break;
         } else if (ca.getDuration() < 1) {
           setErrorMessage("Invalid class duration");
           break;
         } else {
           setErrorMessage(null);
           stmnt2.executeUpdate(sql);
           break;
         }
       }
     }
   } catch (SQLException e) {
     e.printStackTrace();
   } finally {
     if (rs != null) {
       rs.close();
     }
     closeStatement(stmnt);
     closeConnection(conn);
   }
 }
 /**
  * Method that takes a passed class attendance object and adds it to the table in db
  *
  * @author Ognjen Mišiæ
  * @param ca a new entry in to be added to the table
  */
 public static void addClass(ClassAttendance ca) throws SQLException {
   if (ca != null) {
     try {
       conn = connectToDb();
       stmnt = createUpdateableStatement(conn);
       String sql =
           "INSERT INTO classes_attendance (class_description, date, duration) VALUES('"
               + ca.getClassDescription()
               + "','"
               + ca.getDate()
               + "','"
               + ca.getDuration()
               + "');";
       stmnt.executeUpdate(sql);
     } catch (SQLException e) {
       e.printStackTrace();
     } finally {
       closeStatement(stmnt);
       closeConnection(conn);
     }
   }
 }