private static boolean less(ITEM item1, ITEM item2) {
        return item1.less(item2);
    }

private static void exchange(ITEM[] array, int i1, int i2) {
        ITEM temp = array[i2];
        array[i2] = array[i1];
        array[i1] = temp;
    }

private static void compareExchange(ITEM[] array, int i1, int i2) {
        if (less(array[i2], array[i1])) {
            exchange(array, i1, i2);
        }
    }

public static void insertionSort(ITEM[] array, int left, int right) {
        int i;
        for (i = right; i > left; i--) {
            compareExchange(array, i - 1, i);
        }
        for (i = left + 2; i <= right; i++) {
            int j = i;
            ITEM value = array[i];
            while (less(value, array[j - 1])) {
                array[j] = array[j - 1];
                j--;
            }
            array[j] = value;
        }
    }