Question

answer the following question in the java programming language thank you!Definition: The Strategy pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use itYour assignment is to implement the Strategy pattern for the problem of computing an average for a list of submitted grades. The algorithms are as follows:Calculate the average grade for a list of integer numbersCalculate the average grade for a list of integer numbers, dropping the two lowest scoresIn addition, you should develop a set of Junit test cases that sufficiently show that your implementations execute. Finally, your code should be uploaded to repl.itTo get you started, your Strategy interface should look like:public interface AverageStrategy { public int compute(List grades) throws EmptyListException;}Note that your implementations for compute should throw EmptyListException when the method is passed an empty list. The aforementioned exception is a user defined exception and you will need to do a little research on how to create it. You should test the EmptyListException in your JUnit test cases.

Answer 1

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import org.junit.Test;

class EmptyListException extends Exception {
        public EmptyListException() {
                super("The list can not be empty.");
        }
}

interface AverageStrategy {
    public int compute(List<Integer> grades) throws EmptyListException;
}


class Strategy1 implements AverageStrategy {

        @Override
        public int compute(List<Integer> grades) throws EmptyListException {
                if(grades == null || grades.size() < 1) {
                        throw new EmptyListException();
                }

                int count = 0;
                int sum = 0;
                Collections.sort(grades);
                for(int i=0; i<grades.size(); i++) {
                        sum += grades.get(i);
                        count++;
                }
                
                return sum/count;
        }
        
}
class Strategy2 implements AverageStrategy {

        @Override
        public int compute(List<Integer> grades) throws EmptyListException {
                if(grades == null || grades.size() <= 2) {
                        throw new EmptyListException();
                }
                
                int count = 0;
                int sum = 0;
                Collections.sort(grades);
                for(int i=2; i<grades.size(); i++) {
                        sum += grades.get(i);
                        count++;
                }
                
                return sum/count;
        }
        
}

public class AvgTest {

        @Test
        public void testStrategy1() {
                AverageStrategy as = new Strategy1();
                try {
                        assertEquals(2, as.compute(Arrays.asList(1, 2, 3)));
                } catch (EmptyListException e) {
                        fail();
                }
        }


        @Test
        public void testStrategy2() {
                AverageStrategy as = new Strategy2();
                try {
                        assertEquals(3, as.compute(Arrays.asList(1, 2, 3)));
                } catch (EmptyListException e) {
                        fail();
                }
        }


        @Test
        public void testStrategy1Exce() {
                AverageStrategy as = new Strategy1();
                try {
                        as.compute(Arrays.asList());
                        fail();
                } catch (EmptyListException e) {
                }
        }


        @Test
        public void testStrategy2Exce() {
                AverageStrategy as = new Strategy2();
                try {
                        as.compute(Arrays.asList());
                        fail();
                } catch (EmptyListException e) {
                }
        }


}

please upvote.