Question

You are given a specification for some Java classes as follows.  

A building has a number of floors, and a number of windows.

A house is a building.

A garage is a building. (This isn’t Florida-like … it’s a detached garage.)

A room has a length, width, a floor covering, and a number of closets.

You can never create an instance of a building, but every object that is a building must have a method that calculates the floor space, i.e., the Building class is abstract, and has an abstract method.

A house has a number of bathrooms, and an array of Rooms.

A house has a method that returns the average size of the Rooms.

A Garage can hold some number of cars, and it may have a cement floor or a gravel floor. A garage has a length and a width.

1. Describe or Draw the inheritance hierarchy. What inherits from what. (just class names – it's small. Include the Object class in your hierarchy).

2. Implement the specification in Java classes.

You must use the following mechanisms correctly:

Inheritance – is a

Composition – has a

Constructor methods

Accessor / mutator methods = getters, setters

Arrays of objects – you can use ArrayList if you know how

Passing arrays of objects to methods – or an ArrayList

Abstract classes and methods

Access modifiers – public, private (you might find a reason to use protected, it’s not all that common)

toString() methods – in each class

the super keyword

method overriding

method overloading

This program also requires you to demonstrate the OO concepts of:

encapsulation

polymorphism

Include a test class that has a main method. This test program will make instances of your classes and output the text representation of the objects using the toString() methods.    There should be enough comments in the output so that it is easy to see which classes are being tested.

Answer 1

import java.util.*; Try public class ArrayListDemo f public static void main(String args]) // create an array list ArrayList a new ArrayList(); System.out.println("Initial size of al:"al.size()); // add elements to the array list al.add("C" al.add("A") al.add("E al.add("B") al.add("D) al.add("F") al.add (1, "A2"); System.out.println("Size of al after additions:"al.size()); // display the array list System.out.println("Contents of al: "+ al); // Remove elements from the array list al.remove("F") al.remove (2); System.out.println("Size of al after deletions:"al.size()); System.out.println("Contents of al: "al);