用Java中的类替换枚举构造仍然相关吗？

Question

我正在阅读Joshua Bloch在2008年发表的有效Java,其中一个技巧是用类替换枚举结构.这是本书中显示的示例.

public class Suit {
    private final String name;
    public Suit(String name) { this.name = name; }
    public String toString() { return name; }
    public static final Suit CLUBS = new Suit("clubs");
    public static final Suit DIAMONDS = new Suit("diamonds");
    public static final Suit HEARTS = new Suit("hearts");
    public static final Suit SPADES = new Suit("spades");
}

我的问题是,由于Java现在支持枚举类型,使用上述方法仍然是个好主意吗？这是Java枚举类型的示例.

public enum Day {
    SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
    THURSDAY, FRIDAY, SATURDAY 
}

Answer 1

"有效Java"一书在将enums引入语言之前已经写好了,所以我建议使用该enum功能.幸运的是,Java enum是非常通用的,因此您可以使用该enum功能非常密切地遵循Joshua的建议:

public enum Day {
    SUNDAY("Sunday", 0)
,   MONDAY("Monday", 1)
,   TUESDAY("Tuesday", 2)
,   WEDNESDAY("Wednesday", 3)
,   THURSDAY("Thursday", 4)
,   FRIDAY("Friday", 5)
,   SATURDAY("Saturday", 6);

    private String name;
    private int ordinal;
    public String getName() { return name; }
    public int getOrdinal() { return ordinal; }
    public Day(String name, int ordinal) {
        this.name = name;
        this.ordinal = ordinal;
    }
}