test sum

package com.company;

import java.util.logging.Logger;

public class Main {

    private static Logger logger;

    public static void main(String[] args) {
        System.out.println(customSumNumbers(true,  -1));
        System.out.println(customSumNumbers(true, 1,2,3,4));
        System.out.println(customSumNumbers(true, 1,2,-3,-4));
        System.out.println(customSumNumbers(false, 1,2,-3,-4));
        System.out.println(customSumNumbers(true, -1,-1));

        System.out.println(computeAverage(1,2,3,4,5,6));
        System.out.println(computeAverage(1,2,-3,4,5,-6));
    }

    /**
     * Method to sum numbers in a custom way - either sum only positives either the negative ones
     * @param numbers variable length array of integer numbers to be processed
     * @return
     */
    private static int customSumNumbers(boolean sumOnlyPositives, int... numbers) {
        int sum = 0;
        int faultsCount = 0;

        for (int number : numbers) {
            if (sumOnlyPositives && number >= 0) {
                sum += number;  // let's sum only the positives
            } else if (!sumOnlyPositives && number < 0) {
                sum += number;  // let's sum only the negatives
            } else {
                faultsCount++;  // current number is not considered since it is not valid according to the value of sumOnlyPositives flag
            }
        }
        if (faultsCount == numbers.length) {
            System.out.println("WARN | no numbers from the given list respect the sumOnlyPositives flag! Returning default 0 value.");
        }
        return sum;
    }

    private static double computeAverage (int... numbers) {
        return (double) (customSumNumbers(true, numbers) + customSumNumbers(false, numbers)) / (double) numbers.length;
    }
}