/**
* Method that creates a ClassAttendance object
*
* @author Ognjen Mišiæ
* @param classDescription argument describing the class
* @param date of the class
* @param duration duration of the class
* @return an object
* @throws ParseException
*/
public static ClassAttendance createClass(String classDescription, String date, double duration)
throws ParseException {
ClassAttendance ca = new ClassAttendance();
if (classDescription.length() > 2 && classDescription.length() < 45) {
ca.setClassDescription(classDescription);
} else {
setErrorMessage("Class description invalid.");
}
// we reverse validation cause the point is to plan classes ahead and
// enter them to table
if (!isValidDate(date)) {
ca.setDate(date);
} else {
setErrorMessage("Can't plan classes in past.");
}
if (duration > 0) {
ca.setDuration((int) duration);
} else {
setErrorMessage("Invalid duraton.");
}
// this checks if there is anything in errormessage so it returns a null
// object if there is an error
if (getErrorMessage() != null && !getErrorMessage().isEmpty()) {
return null;
} else {
return ca;
}
}
/**
* Method that returns object of class attendance
*
* @author Ognjen Mišiæ
* @param classID we identify entry by its classID
* @return Object ClassAttendance
* @throws SQLException
*/
public static ClassAttendance returnClassAttendance(int classID) throws SQLException {
ClassAttendance ca = new ClassAttendance();
try {
conn = connectToDb();
stmnt = createReadOnlyStatement(conn);
rs = stmnt.executeQuery(SELECT_ALL_FROM_CLASSES_ATTENDANCE);
while (rs.next()) {
if (rs.getInt("class_id") == classID) {
ca.setClassDescription(rs.getString("class_description"));
ca.setDate(rs.getString("date"));
ca.setDuration(rs.getInt("duration"));
ca.setClassID(rs.getInt("class_id"));
setErrorMessage(null);
break;
} else {
setErrorMessage("Could not find selected class id");
}
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
if (rs != null) {
rs.close();
}
closeStatement(stmnt);
closeConnection(conn);
}
// this checks if there is anything in errormessage so it returns a null
// object if there is an error
if (getErrorMessage() != null && !getErrorMessage().isEmpty()) {
return null;
} else {
return ca;
}
}
/**
* 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);
}
}
}
/**
* 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);
}
}
