Question

Define subclasses of InvalidTimeException

InvalidHourException and InvalidMinuteException

Public static methods:

checkHour(String hh), checkMinute(String mm)

Test ≥ 2 strings; if invalid, throw an appropriate exception

java

Answer 1

Here is the completed code for the two required exception classes. Assuming InvalidTimeException is already defined, and has a constructor taking String value. Testing of the checkHour method and checkMinute method is done inside main method of each exception class respectively. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. If not, PLEASE let me know before you rate, I’ll help you fix whatever issues. Thanks

Make sure you copy below two classes into separate files as mentioned. Do not copy everything to a single file.

//InvalidHourException.java

public class InvalidHourException extends InvalidTimeException {

      // constructor taking an error message

      public InvalidHourException(String msg) {

            // passing error message to super class. assuming InvalidTimeException

            // has a constructor taking String argument, if not either add one, or

            // remove this constructor

            super(msg);

      }

      // method to check if a hour value is valid. does nothing if hour is

      // valid, throws InvalidHourException if hour is invalid

      public static void checkHour(String hh) throws InvalidHourException {

            // setting a flag error to true if either hh is null or if it has length

            // greater than 2

            boolean error = hh == null || hh.length() > 2;

            // parsing hours as integer

            try {

                  int h = Integer.parseInt(hh);

                  // if h is outside the range 1-12, setting error to true

                  if (h < 1 || h > 12) {

                        error = true;

                  }

            } catch (Exception e) {

                  // if any exception occurred while parsing, setting error to true

                  error = true;

            }

            // if error is true, throwing InvalidHourException

            if (error) {

                  throw new InvalidHourException("Invalid hour");

            }

      }

      // main method for testing

      public static void main(String[] args) {

            // testing checkHour method with three test cases

            String h = "12";

            System.out.println("Testing hour=" + h);

            try {

                  checkHour(h);

                  // if no exception is occurred, displaying that hour is valid

                  System.out.println(h + " is valid");

            } catch (InvalidHourException e) {

                  System.out.println(e.getMessage());

            }

            h = "01";

            System.out.println("Testing hour=" + h);

            try {

                  checkHour(h);

                  System.out.println(h + " is valid");

            } catch (InvalidHourException e) {

                  System.out.println(e.getMessage());

            }

            h = "-2";

            System.out.println("Testing hour=" + h);

            try {

                  checkHour(h);

                  System.out.println(h + " is valid");

            } catch (InvalidHourException e) {

                  System.out.println(e.getMessage());

            }

      }

}

//InvalidMinuteException.java

public class InvalidMinuteException extends InvalidTimeException {

      // constructor taking an error message

      public InvalidMinuteException(String msg) {

            // passing error message to super class. assuming InvalidTimeException

            // has a constructor taking String argument, if not either add one, or

            // remove this constructor

            super(msg);

      }

      // method to check if a minute value is valid. does nothing if minute is

      // valid, throws InvalidMinuteException if hour is invalid

      public static void checkMinute(String mm) throws InvalidMinuteException {

            // setting a flag error to true if either mm is null or if it has length

            // greater than 2

            boolean error = mm == null || mm.length() > 2;

            // parsing minute

            try {

                  int m = Integer.parseInt(mm);

                  // if m is outside the range 0-59, setting error to true

                  if (m < 0 || m > 59) {

                        error = true;

                  }

            } catch (Exception e) {

                  // if any exception occurred while parsing, setting error to true

                  error = true;

            }

            // if error is true, throwing InvalidMinuteException

            if (error) {

                  throw new InvalidMinuteException("Invalid minute");

            }

      }

      // main method for testing

      public static void main(String[] args) {

            // testing checkMinute method with three test cases

            String m = "26";

            System.out.println("Testing minute=" + m);

            try {

                  checkMinute(m);

                  System.out.println(m + " is valid");

            } catch (InvalidMinuteException e) {

                  System.out.println(e.getMessage());

            }

            m = "66";

            System.out.println("Testing minute=" + m);

            try {

                  checkMinute(m);

                  System.out.println(m + " is valid");

            } catch (InvalidMinuteException e) {

                  System.out.println(e.getMessage());

            }

            m = "-2";

            System.out.println("Testing minute=" + m);

            try {

                  checkMinute(m);

                  System.out.println(m + " is valid");

            } catch (InvalidMinuteException e) {

                  System.out.println(e.getMessage());

            }

      }

}