Question

Is it possible to have an enum change its value (from inside itself)? Maybe it’s easier to understand what I mean with code:

enum Rate {
    VeryBad(1),
    Bad(2),
    Average(3),
    Good(4),
    Excellent(5);

    private int rate;

    private Rate(int rate) {
        this.rate = rate;
    }

        public void increateRating() {
            //is it possible to make the enum variable increase?
            //this is, if right now this enum has as value Average, after calling this
            //method to have it change to Good?
       }
}

This is want I wanna achieve:

Rate rate = Rate.Average;
System.out.println(rate); //prints Average;
rate.increaseRating();
System.out.println(rate); //prints Good

Thanks

Answer 1

Yes. You could simply call

rate = Rate.Good;

for this specific case. But what I think you are really looking for is a successor function.

Here you are:

public class EnumTest extends TestCase {
    private enum X {
        A, B, C;
        public X successor() {
                return values()[(ordinal() + 1) % values().length];
        }
    };

    public void testSuccessor() throws Exception {
        assertEquals(X.B, X.A.successor());
        assertEquals(X.C, X.B.successor());
        assertEquals(X.A, X.C.successor());
    }
}