Explicit comparator based on guava explicit ordering

If an element is not in the explicit list, it will be the last in the order

import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@ToString
@EqualsAndHashCode
public final class ExplicitComparator<T> implements Comparator<T>
{
    private final Map<T, Integer> rankMap;

    private ExplicitComparator(List<T> valuesInOrder)
    {
        this.rankMap = buildRankMap(valuesInOrder);
    }

    public static <T> ExplicitComparator<T> of(List<T> valuesInOrder)
    {
        return new ExplicitComparator<>(valuesInOrder);
    }

    private static <T> Map<T, Integer> buildRankMap(List<T> valuesInOrder)
    {
        Map<T, Integer> map = new HashMap<>();

        int rank = 0;
        for (T value : valuesInOrder)
        {
            map.put(value, rank++);
        }

        return map;
    }

    @Override
    public int compare(T left, T right)
    {
        return rank(left) - rank(right);
    }

    private int rank(T value)
    {
        Integer rank = rankMap.get(value);

        if (rank == null)
        {
            return rankMap.size();
        }

        return rank;
    }
}