11.1 Activity: Designing inheritance hierarchies

Task 1

Order the following lists of items into an inheritance hierarchy.

(a) banana, cake, bread, fruit, food item, pasta, apple, dessert, jelly, bagel

(b) vehicle, aircraft, boat, helicopter, bicycle, hovercraft, plane, car, bus, watercraft, spacecraft, motor vehicle

Task 2

Draw an inheritance hierarchy for people at Monash University.

Some types of people you might include are:

student, undergraduate student, postgraduate student, staff, lecturer, teaching assistant, Monash community member, gardener, librarian.

How do each of these person types relate to one another?

Answer

Task 1
(a)
food item
    bread
        cake
        bagel
    fruit
        banana
        apple
    dessert
        cake
        jelly
(b)
vehicle
    aircraft
        plane
        helicopter
    bicycle
    hovercraft
    watercraft
        boat
    spacecraft
    motor vehicle
        car
        bus
Task 2
Monash community member
    student
        undergraduate student
        postgraduate student
    staff
        lecturer
        teaching assistant
        gardener
        librarian

11.2 Activity: Implementing Inheritance

Write a super class and subclasses in Java to implement the inheritance hierarchy you designed in Activity 11.1 Task 2. (Recall that Java does not support multiple inheritance, so if your inheritance hierarchy illustrates multiple inheritance relationships, you will need to decide how to simplify it.)

Include appropriate constructors, fields, and accessor/mutator methods for each class. Where classes have attributes/methods in common, make sure these attributes/methods are defined as far up the hierarchy as possible.

To get you started, some of the fields you might need are: name, studentId, staffId.

Answer