ENUMs

Here is my Soldier class

package militaryStructure;

public class Soldier {

    public enum Rank { PRIVATE, PFC, CORPORAL, SERGENT,
        CAPTAIN, MAJOR, LT_COLONEL, COLONEL, GENERAL, ADMIRAL}

    private String name;
    private Rank rank;
    private int serialNumber;
    public Soldier(String name, Rank rank, int serialNumber) {
        this.name = name;
        this.rank = rank;
        this.serialNumber = serialNumber;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Rank getRank() {
        return rank;
    }
    public void setRank(Rank rank) {
        this.rank = rank;
    }
    public int getSerialNumber() {
        return serialNumber;
    }
    public Rank promote(Rank rank) {
        int x = rank.ordinal() + 1;
        if ( x < 11 )
            x++;
        return Rank.ADMIRAL;
    }
}

If I want to promote a soldier, I have a method called promote that
takes in a rank of the Enum Rank type. My thinking is that since each
"rank" has an ordinal, then I should be able to
a) determine ordinal of the current rank int x = rank.ordinal() + 1;
b) increment the ordinal x++;
c) return the Rank in the position of the incremented ordinal

But I can't find a method attached to Rank which will let me do this.
Is there a way to do this without having to change anything in my code
besides the promote method?

I've looked in the API and done a google search but either there isn't a
  way to do what I want or I've missed something.... Note: This is just
an experiment..I am NOT taking this any further than trying to construct
a Soldier and promote him/her to the next rank. My ranks are not
correct, just remembering from M.A.S.H so don't flame me. All I want to
know is how to pass back the next up rank... I can't have all my
soldiers getting promoted to Admiral.