implements Serializable {
    static final Converter<String, Integer> INSTANCE = new IntConverter();

    @Override
    protected Integer doForward(String value) {
      return Integer.decode(value);
    }

    @Override
    protected String doBackward(Integer value) {
      return value.toString();
    }

    @Override

  private static final class FloatConverter extends Converter<String, Float>
      implements Serializable {
    static final Converter<String, Float> INSTANCE = new FloatConverter();

    @Override
    protected Float doForward(String value) {
      return Float.valueOf(value);
    }

    @Override
    protected String doBackward(Float value) {
      return value.toString();
    }

    @Override

      implements Serializable {
    static final Converter<String, Double> INSTANCE = new DoubleConverter();

    @Override
    protected Double doForward(String value) {
      return Double.valueOf(value);
    }

    @Override
    protected String doBackward(Double value) {
      return value.toString();
    }

    @Override

  private static final class FloatConverter extends Converter<String, Float>
      implements Serializable {
    static final Converter<String, Float> INSTANCE = new FloatConverter();

    @Override
    protected Float doForward(String value) {
      return Float.valueOf(value);
    }

    @Override
    protected String doBackward(Float value) {
      return value.toString();
    }

    @Override

      implements Serializable {
    static final Converter<String, Double> INSTANCE = new DoubleConverter();

    @Override
    protected Double doForward(String value) {
      return Double.valueOf(value);
    }

    @Override
    protected String doBackward(Double value) {
      return value.toString();
    }

    @Override

  }

  private static final class LongConverter extends Converter<String, Long> implements Serializable {
    static final Converter<String, Long> INSTANCE = new LongConverter();

    @Override
    protected Long doForward(String value) {
      return Long.decode(value);
    }

    @Override
    protected String doBackward(Long value) {
      return value.toString();
    }

    @Override

  }

  private static final class LongConverter extends Converter<String, Long> implements Serializable {
    static final Converter<String, Long> INSTANCE = new LongConverter();

    @Override
    protected Long doForward(String value) {
      return Long.decode(value);
    }

    @Override
    protected String doBackward(Long value) {
      return value.toString();
    }

    @Override

    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);
    }