Flippable benchmark

/*  0% Scenario{vm=java, trial=0, benchmark=FlipOne} 12.23 ns; ?=0.12 ns @ 6 trials
 * 50% Scenario{vm=java, trial=0, benchmark=FlipTwo} 18.89 ns; ?=0.43 ns @ 10 trials

 * benchmark   ns linear runtime
 *   FlipOne 12.2 ===================
 *   FlipTwo 18.9 ==============================

 * vm: java
 * trial: 0
 */

import java.util.Random;

import com.google.caliper.Runner;
import com.google.caliper.SimpleBenchmark;

public class FlipTest {
    public static enum FlipOne {
        A, B, Z, Y;

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

        public FlipOne flip() {
            return opposite;
        }

        private FlipOne opposite;
    }

    public static enum FlipTwo {
        A ("Z"), B ("Y"), Y ("B"), Z ("A");

        private final String opposite;

        private FlipTwo(String opposite) {
            this.opposite = opposite;
        }

        public FlipTwo flip() {
            return valueOf(opposite);
        }
    }

    public static class TestBenchmark extends SimpleBenchmark {
        private Random r;
        private int[] counters;

        @Override
        protected void setUp() throws Exception {
            r = new Random();
            counters = new int[4];
        }

        public int timeFlipOne(int reps) {
            for (int i = 0; i < reps; i++) {
                FlipOne randomFlip = FlipOne.values()[r.nextInt(4)];
                counters[randomFlip.flip().ordinal()]++;
            }
            return counters[0] * counters[1] * counters[2] * counters[3];
        }

        public int timeFlipTwo(int reps) {
            for (int i = 0; i < reps; i++) {
                FlipTwo randomFlip = FlipTwo.values()[r.nextInt(4)];
                counters[randomFlip.flip().ordinal()]++;
            }
            return counters[0] * counters[1] * counters[2] * counters[3];
        }
    }

    public static void main(String[] args) {
        Runner.main(TestBenchmark.class, new String[0]);
    }
}