BucketStateViewer.java

import lombok.Data;
import lombok.experimental.Accessors;

public class BucketStateViewer {
    public static void main(String[] args) {
        BucketState valid = new BucketState()
                .setObserver(ObserverRelativeToCenter.LEFT)
                .setObserved(ObservedRelativeToCenter.LEFT)
                .setRelative(ObservedRelativeToObserver.LEFT)
                .setDistance(Distance.INCREASING)
                .setRelativeVelocity(RelativeVelocity.DECREASING);
        System.out.println(valid);
        System.out.println(valid.amIValid());

        BucketState invalid = new BucketState()
                .setObserver(ObserverRelativeToCenter.LEFT)
                .setObserved(ObservedRelativeToCenter.LEFT)
                .setRelative(ObservedRelativeToObserver.RIGHT)
                .setDistance(Distance.INCREASING)
                .setRelativeVelocity(RelativeVelocity.INCREASING);
        System.out.println(invalid);
        System.out.println(invalid.amIValid());
    }

    enum ObserverRelativeToCenter {
        LEFT, RIGHT, EQUALS,
    }

    enum ObservedRelativeToCenter {
        LEFT, RIGHT, EQUALS,
    }

    enum ObservedRelativeToObserver {
        LEFT, RIGHT, EQUALS
    }

    // ObserverObservedDistanceD1
    enum Distance {
        INCREASING, DECREASING,
    }

    // ObserverObservedDistanceD2
    enum RelativeVelocity {
        INCREASING, DECREASING,
    }

    @Accessors(chain = true)
    @Data
    static class BucketState {
        ObserverRelativeToCenter observer;
        ObservedRelativeToCenter observed;
        ObservedRelativeToObserver relative;
        Distance distance;
        RelativeVelocity relativeVelocity;

        boolean amIValid() {
            if (observer == ObserverRelativeToCenter.LEFT &&
                    observed == ObservedRelativeToCenter.LEFT &&
                    relative == ObservedRelativeToObserver.RIGHT)
                return false;

            return true;
        }
    }
}