Using nested enum types in Java

Question

I have a data structure in mind that involves nested enums, such that I could do something like the following:

Drink.COFFEE.getGroupName();
Drink.COFFEE.COLU         


        

Answer 1

I was recently curious myself if this could be done somewhat satisfactorily. This is the solution I ended up with, whose API I think also closer matches the tree structure of enums that the asker originally wanted:

public interface Drink {

    String groupName();
    String label();

    enum Coffee implements Drink {

        COLUMBIAN("Columbian Blend"),
        ETHIOPIAN("Ethiopian Blend");

        private final String label;

        Coffee(String label) {
            this.label = label;
        }

        @Override
        public String groupName() {
            return "Coffee";
        }

        @Override
        public String label() {
            return label;
        }
    }

    enum Tea implements Drink {

        MINT("Mint"),
        HERBAL("Herbal"),
        EARL_GREY("Earl Grey");

        private final String label;

        Tea(String label) {
            this.label = label;
        }

        @Override
        public String groupName() {
            return "Tea";
        }

        @Override
        public String label() {
            return label;
        }
    }
}

public static void main(String[] args) {
    Drink choice = Drink.Tea.EARL_GREY;

    System.out.println(choice.groupName());  // Tea
    System.out.println(choice.label());  // Earl Grey
}