Sorting a deck of cards by suit and then rank

Question

I have this Java class:

class Card
{
    private Suit suit;
    private int  rank;
}

(Suit is an enum)

There are four suits with ranks 1-9 each and four suits with a single possible rank 0. Each card exists in an unknown but constant among all cards number of copies. How would I sort a deck in a set order of suits, and by increasing rank in each suit?

Answer 1

You'll need to either

1. implement the Comparable interface on the card object: add a compareTo function that determines whether another card should be before or after this one in the sort order
2. implement a Comparator object that accepts two cards and indicates which order they should appear in

and then you can use Collections.sort on your list.