Java Data Type - 如何使用不可变参数创建自参照枚举

enum Value {
    A, B, Z, Y;

    static {
        A.opposite = Z;
        B.opposite = Y;
        Y.opposite = B;
        Z.opposite = A;
    }

    public Value flip() {
        return opposite;
    }

    private Value opposite;


}
public class Main{
  public static void main(String[] args) {         
    for(Value f : Value.values()) {
        System.out.println(f + " flips to " + f.flip());
    }
}
}