IntegerArrayUtils.java

package com.dtcc.exams.arrays;

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

public class IntegerArrayUtils {
    /**
     * @param integerArray - array to have value added to it
     * @param valueToBeAdded - value to be added to the end of the array
     * @return - identical array with one additional element of `valueToBeAdded` at the end of the array
     */
    public static Integer[] add(Integer[] integerArray, Integer valueToBeAdded) {
        // convert the array to a list and back to array after adding
        List<Integer> integerList = new ArrayList<Integer>(Arrays.asList(integerArray));
        integerList.add(valueToBeAdded);
        integerArray = integerList.toArray(integerArray);
        return integerArray;
    }

    /**
     * @param integerArray - array to be manipulated
     * @param indexToInsertAt - index of the element to be inserted at
     * @param valueToBeInserted - value of the element to be inserted
     * @return `integerArray` with `valueToBeInserted` at index number `indexToInsertAt`
     */
    public static Integer[] replace(Integer[] integerArray, int indexToInsertAt, Integer valueToBeInserted) {
        List<Integer> integerList = new ArrayList<Integer>(Arrays.asList(integerArray));
        integerList.set(indexToInsertAt, valueToBeInserted);
        integerArray = integerList.toArray(integerArray);

        return integerArray;
    }

    /**
     * @param integerArray - array to be evaluated
     * @param indexToFetch - index of element to be returned
     * @return element located at `indexToFetch`
     */
    public static Integer get(Integer[] integerArray, Integer indexToFetch) {

        return integerArray[indexToFetch];
    }

    /**
     * @param integerArray - array to be evaluated
     * @return identical array with even-values incremented by 1 and odd-values decremented by 1
     */
    public static Integer[] incrementEvenDecrementOdd(Integer[] integerArray) {

        for(int i= 0 ; i < integerArray.length; i++){
            if(integerArray[i] % 2 == 0){
                integerArray[i] = integerArray[i] + 1;
            }
            else integerArray[i] = integerArray[i] -1;
        }
        return integerArray;
    }

    /**
     * @param integerArray - array to be evaluated
     * @return identical array with even-values incremented by 1
     */
    public static Integer[] incrementEven(Integer[] integerArray) {
        for(int i= 0 ; i < integerArray.length; i++){
            if(integerArray[i] % 2 == 0){
                integerArray[i] = integerArray[i] + 1;
            }
        }
        return integerArray;
    }

    /**
     * @param input - array to be evaluated
     * @return identical array with odd-values decremented by 1
     */
    public static Integer[] decrementOdd(Integer[] input) {
        for(int i= 0 ; i < input.length; i++){
            if(input[i] % 2 != 0){
                input[i] = input[i] - 1;
            }
        }
        return input;
    }
}