Guava style accessors chaining example

/* OPs POJO classes structure (here https://stackoverflow.com/a/45221474/3225638) */
record A(B item) {
    record B(Long value) {
    }
}

/* Unit test example for chained accessors */
@Test
public void testChainAccessors() {
    var list = new ArrayList<A>();
    for (long i = 0L; i < 10; i++)
        list.add(new A(new A.B(i)));
    Stream<A> stream = list.stream();
    final var count = new AtomicLong(0);
    stream.sorted(Comparator.comparing(chain(A::item, A.B::value)))     // <-- example with 2 chained functions
            .map(chain(A::item, A.B::value, Long::toHexString))         // <-- example with 3
            .forEachOrdered(string -> assertThat(string).isEqualTo(Long.toHexString(count.getAndIncrement())));
}

/**
 * If you want to avoid casting an accessor method reference into a Function,
 * use a static utility func to do that for us, so you can statically import
 * later
 * Caveats:
 * - it's really hard to use lambdas with primitive types, so you'd
 * have to make sure all your classes use the boxed wrapper types
 * - Don't go into a rabbit hole of using this everywhere and creating
 * functions for every type of lambda combination, it's the compiler's job
 * not yours.. Use C# instead
 */
interface FunctionComposer {
    static <I, T, O> Function<I, O> chain(Function<I, T> first, Function<T, O> second) {
        return first.andThen(second);
    }

    // C# style helper utility methods
    static <I, T1, T2, O> Function<I, O> chain(Function<I, T1> f1, Function<T1, T2> f2, Function<T2, O> f3) {
        return f1.andThen(f2).andThen(f3);
    }

    /* etc... */
}