Konami

gistfile1.java

final Broadcaster<Integer> keyboardStream = Broadcaster.create();

Promise<List<Boolean>> konamis = keyboardStream
    .skipWhile(key -> KeyEvent.VK_UP != key)
    .buffer(10, 1)
    .map(keys -> keys.size() == 10 &&
            keys.get(0) == KeyEvent.VK_UP &&
            keys.get(1) == KeyEvent.VK_UP &&
            keys.get(2) == KeyEvent.VK_DOWN &&
            keys.get(3) == KeyEvent.VK_DOWN &&
            keys.get(4) == KeyEvent.VK_LEFT &&
            keys.get(5) == KeyEvent.VK_RIGHT &&
            keys.get(6) == KeyEvent.VK_LEFT &&
            keys.get(7) == KeyEvent.VK_RIGHT &&
            keys.get(8) == KeyEvent.VK_B &&
            keys.get(9) == KeyEvent.VK_A
    )
    .toList();

keyboardStream.onNext(KeyEvent.VK_UP);
keyboardStream.onNext(KeyEvent.VK_UP);
keyboardStream.onNext(KeyEvent.VK_UP);
keyboardStream.onNext(KeyEvent.VK_DOWN);
keyboardStream.onNext(KeyEvent.VK_DOWN);
keyboardStream.onNext(KeyEvent.VK_LEFT);
keyboardStream.onNext(KeyEvent.VK_RIGHT);
keyboardStream.onNext(KeyEvent.VK_LEFT);
keyboardStream.onNext(KeyEvent.VK_RIGHT);
keyboardStream.onNext(KeyEvent.VK_B);
keyboardStream.onNext(KeyEvent.VK_A);
keyboardStream.onNext(KeyEvent.VK_C);
keyboardStream.onComplete();

System.out.println(konamis.await());