@GwtCompatible
@NullUnmarked
public class ConverterTest extends TestCase {

  private static final Converter<String, Long> STR_TO_LONG =
      new Converter<String, Long>() {
        @Override
        protected Long doForward(String object) {
          return Long.valueOf(object);
        }

        @Override
        protected String doBackward(Long object) {
          return String.valueOf(object);
        }

        @Override

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

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

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

    @Override

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

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

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

    @Override

      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