private final BiMap<A, B> bimap;

    BiMapConverter(BiMap<A, B> bimap) {
      this.bimap = checkNotNull(bimap);
    }

    @Override
    protected B doForward(A a) {
      return convert(bimap, a);
    }

    @Override
    protected A doBackward(B b) {
      return convert(bimap.inverse(), b);
    }

    private final BiMap<A, B> bimap;

    BiMapConverter(BiMap<A, B> bimap) {
      this.bimap = checkNotNull(bimap);
    }

    @Override
    protected B doForward(A a) {
      return convert(bimap, a);
    }

    @Override
    protected A doBackward(B b) {
      return convert(bimap.inverse(), b);
    }