gistfile1.txt

Java:

public List<Item> bought(User user)
{
    List<Item> result = new ArrayList();
    for (Item item : currentItems)
    {
        if (user.bought(item))
        {
            result.add(item);
        }
    }
    return result;
}

Scala:
def bought(user: User) = items.filter(user bought _)