java - Java中有类似嵌套枚举的东西吗？

Question

我想做一个 Country 枚举，我可以从中访问其状态，我该怎么做？

类似这样的:

public enum SomeEnum {

     ARGENTINA {
       BUENOS_AIRES;
     }

     UNITED_STATES {
       CALIFORNIA, FLORIDA, NEW_YORK, ALASKA;
     }

}

SomeEnum state1 = SomeEnum.ARGENTINA.BUENOS_AIRES
SomeEnum state2 = SomeEnum.UNITED_STATES.CALIFORNIA;

Answer 1

你可以使用类似的界面

interface Country {
    Country USA = Americas.USA;

    enum Asia implements Country {
        Indian,
        China,
        SriLanka
    }
    enum Americas implements Country {
        USA,
        Brazil
    }
    enum Europe implements Country {
        UK,
        Ireland,
        France
    }
}

你可以拥有

Country c = Country.USA;
c = Country.Asia.China;