java - 如何将对象添加到枚举定义的类中？

Question

我正在尝试遵循 Oracle 文档中的这段代码，它向您展示了如何使用 Java ENUMS。但是，我试图在最后的 protoDeck 中添加一个“ clown ”因为每副 52 张牌可以包含一张额外的“ clown ”或“ clown ”牌。我无法将 CLOWN 添加到 SUIT 或 RANK，因为它们都不是。

我尝试创建一个新的 enum作为

   public enum Clown {Clown} 

并试图将其放入 protoDeck 但它不起作用

    public class Card {
        public enum Rank { DEUCE, THREE, FOUR, FIVE, SIX,
            SEVEN, EIGHT, NINE, TEN, JACK, QUEEN, KING, ACE }

        public enum Suit { CLUBS, DIAMONDS, HEARTS, SPADES }

        private final Rank rank;
        private final Suit suit;
        private Card(Rank rank, Suit suit) {
            this.rank = rank;
            this.suit = suit;
        }

        public Rank rank() { return rank; }
        public Suit suit() { return suit; }
        public String toString() { return rank + " of " + suit; }

        private static final List<Card> protoDeck = new ArrayList<Card>();

        // Initialize prototype deck
        static {
            for (Suit suit : Suit.values())
                for (Rank rank : Rank.values())
                    protoDeck.add(new Card(rank, suit));
        }

        public static ArrayList<Card> newDeck() {
            return new ArrayList<Card>(protoDeck); // Return copy of prototype deck
        }
    }

Answer 1

将Card变成一个接口(interface)。

您可以将 Clown 链接到与其他卡片相同的组中，只要让它在这些情况下也表现得适当即可。所以你会有类似的东西:

public interface Card {
  Rank getRank();
  Suit getSuit();
}

public enum Rank { DEUCE, THREE, FOUR, FIVE, SIX,
        SEVEN, EIGHT, NINE, TEN, JACK, QUEEN, KING, ACE, OTHER }

public enum Suit { CLUBS, DIAMONDS, HEARTS, SPADES, NONE }

public class RegularCard implements Card {
    private RegularCard(Rank rank, Suit suit) {
        this.rank = rank;
        this.suit = suit;
    }

    public Rank getRank() { return rank; }
    public Suit getSuit() { return suit; }
}

public enum MiscellaneousCards implements Card {
  CLOWN, JOKER;

  // etc.
}