Java By Comparison

Favor Functional Over Imperative Style

class Inventory {

    List<Supply> supplies = new ArrayList<>();

    long countDifferentKinds() {
        List<String> names = new ArrayList<>();
        for (Supply supply : supplies) {
            if (supply.isUncontaminated()) {
                String name = supply.getName();
                if (!names.contains(name)) {
                    names.add(name);
                }
            }
        }
        return names.size();
    }
}

When it comes to working with collections, a functional programming style can be much more readable than its imperative sibling.

Above, you can see a short but relatively complex method that does some very common things: it iterates over a collection and does a few conditional computations. Even though the code’s short and named properly, you need a moment to ...