Question

The aims of this lab are: 

1. Understand the purpose of exception handling

2. How to create your own exception class.

3. Use of assertion

1. Create a class TutorialSpace that used to enrol student in a tutorial class. It should have the following private attributes:

• slots — the number of available slots in a tutorial class

• activated — true if the tutorial class has been activated 

  
  

and the following methods:

• TutorialSpace(n) — a constructor for a tutorial class with n slots. 

• activate() — activates the tutorial class. Throws an exception if the tutorial class has already been activated. 

• reserveSlot()—enrol a student into the tutorial class by decreasing the number of slots left for enrolling in the class. Throws an exception if slot is either completely used or the tutorial class is not active. 

• slotsRemaining()—returns the number of slots remaining in the tutorial class.

To handle the two exceptions as described before, you will need to write two exception classes: NotActivatedException and EmptyException

2. Write a client program, registerClass, to test the use of the TutorialSpace class. Make sure you consider a testing strategy that can test all the methods and exceptions in the TutorialSpace class. 

Answer 1

public class TutorialSpace {

        

        // slots — the number of available slots in a tutorial class

        private int slots;

        // activated — true if the tutorial class has been activated

        private boolean activated;

        

        /**

        * TutorialSpace(n) — a constructor for a tutorial class with n slots.

        * 

        * @param n

        */

        public TutorialSpace(int n) {

                this.slots = n;

                this.activated = false;

        }

        

        /**

        * activate() — activates the tutorial class. Throws an exception if the

        * tutorial class has already been activated.

        * 

        * @throws NotActivatedException

        */

        

        public void activate() throws NotActivatedException {

                if (activated) {

                        throw new NotActivatedException("Already Activated");

                } else {

                        activated = true;

                }

        }

        

        /**

        * reserveSlot()—enrol a student into the tutorial class by decreasing the

        * number of slots left for enrolling in the class. Throws an exception if slot

        * is either completely used or the tutorial class is not active.

        * 

        * @throws EmptyException

        */

        public void reserveSlot() throws EmptyException {

                

                if (!activated || slots == 0) {

                        throw new EmptyException("Tutorial space is empty");

                } else {

                        slots--;

                }

        }

        

        /**

        * slotsRemaining()—returns the number of slots remaining in the tutorial class.

        */

        

        public int slotsRemaining() {

                return slots;

        }

        

}

public class NotActivatedException extends Exception {

        

        /**

        * 

        */

        private static final long serialVersionUID = 1L;

        

        public NotActivatedException(String msg) {

                super(msg);

        }

        

}

public class EmptyException extends Exception {

        

        /**

        * 

        */

        private static final long serialVersionUID = 1L;

        public EmptyException(String msg) {

                super(msg);

        }

        

        

}