Measurable Objects

PART 1

• Create a Country class that implements the interface Measurable.
  • A country has the name (String) of the country and its land's surface area (double).
  • The method getMeasurement should return the surface area.
• You are given the interface Measurable and driver class MeasurableTester
• Make sure the driver, MeasurableTester works with you new Country class.

PART 2

• Modify the Measurable interface by writing code for the static interface method: public static Measurable max(Measurable[] list) This method returns the object from the list that has the largest (measurable) value.
• Uncomment the section for Part 2 in the MeasurableTester that calls the new method on the given array of countries, and prints out the largest Country in the array.

PART 3

• Modify the Country class to implement the Java API's Comparable Interface based on the surface area
• Recall the Comparable interface from the lecture slides or refer to https://docs.oracle.com/en/java/javase/15/docs/api/java.base/java/lang/Comparable.html (Links to an external site.) to know how to implement the abstract method.
• At the class declaration line, use: implements Comparable
• Write code implementation for the method: public int compareTo(Country c)
• Note: You are comparing each Country object's surface area to the other
• Uncomment MeasurableTester code for part 3.
• Make sure the countries printed out are in order now!
• Arrays.sort is an API method that sorts elements in an array that has implemented the Comparable interface.
• In class, we used Collections.sort, an API method that sorts elements stored in an ArrayList
• The API's sorting algorithm works without you needed to know how its done as long as you implement the interface. Yay!

PART 4

• Create a class Mdterm that implements the Measurable interface.
  • A Mdterm object has both the score (double) and a student's name (String).
• Create a new driver program MdtermTester to create and process an array of Mdterm objects. This driver program has similar functionality as the previous MeasurableTester program.
  • Create 10 Mdterm objects -- you can decide on the name and scores of each object
  • Print each object (name and score)
  • Display the average score of the 10 objects (using the interface method)
  • Display the student with the highest score (using the interface method)
  • sort the mdterm objects using the Arrays.sort method
  • Print the sorted objects.

Starter Codes

Measurable.java

public interface Measurable
{
double getMeasurement();
/**
Computes the average of the measures of the given objects.
@param objects an array of Measurable objects
@return the average of the measures
*/
public static double average(Measurable[] objects)
{
double sum = 0.0;
for (Measurable obj : objects)
{
sum = sum + obj.getMeasurement();
}
if (objects.length > 0)
{
return sum / objects.length;
} else {
return 0.0;
}
}
/**
Finds the maximum of the measurements of the given objects.
@param objects an array of Measurable objects
@return the maximum of the measures, null if array is empty
*/
public static Measurable max(Measurable[] objects)
{
// WRITE CODE HERE
return null;
}
}

MeasurableTester.java

/**
This program demonstrates the measurable Country class.
*/
import java.util.*;
public class MeasurableTester
{
public static void main(String[] args)
{
Measurable[] countries = new Measurable[3];
countries[0] = new Country("Uruguay", 176220);
countries[1] = new Country("Thailand", 513120);
countries[2] = new Country("Belgium", 30510);
for(Measurable c: countries)
System.out.println(c);
System.out.println("nThe average surface are of these countries is: " +
Measurable.average(countries));
System.out.println("Expected: 239950.0");
/* ---------------- PART 2 ----------------------
Measurable maxCountry = Measurable.max(countries);
System.out.println("nMaximum area: " + maxCountry.getMeasurement());
System.out.println("Expected: 513120");
*/
/* ---------------- PART 3 ----------------------
Arrays.sort(countries);
for(Measurable c: countries)
System.out.println(c);
*/
}
}