java FI BinaryOperator

Posted 2021-05-07

public void testIntMethods() {
    BinaryOperator<Integer> sum1 = Integer::sum;
    IntBinaryOperator sum2 = Integer::sum;
    BinaryOperator<Integer> max1 = Integer::max;
    IntBinaryOperator max2 = Integer::max;
    BinaryOperator<Integer> min1 = Integer::min;
    IntBinaryOperator min2 = Integer::min;
    Comparator<Integer> cmp = Integer::compare;

    int[] numbers = { -1, 0, 1, 100, Integer.MAX_VALUE, Integer.MIN_VALUE };
    for (int i : numbers) {
        for (int j : numbers) {
            assertEquals(i+j, (int) sum1.apply(i, j));
            assertEquals(i+j, sum2.applyAsInt(i, j));
            assertEquals(Math.max(i,j), (int) max1.apply(i, j));
            assertEquals(Math.max(i,j), max2.applyAsInt(i, j));
            assertEquals(Math.min(i,j), (int) min1.apply(i, j));
            assertEquals(Math.min(i,j), min2.applyAsInt(i, j));
            assertEquals(((Integer) i).compareTo(j), cmp.compare(i, j));
        }
    }
}