*       Stream.map}).
 *   <li><b>Do not</b> call {@link #doForward} or {@link #doBackward} directly; these exist only to
 *       be overridden.
 * </ul>
 *
 * <h3>Example</h3>
 *
 * <pre>
 *   return new Converter&lt;Integer, String&gt;() {
 *     protected String doForward(Integer i) {
 *       return Integer.toHexString(i);
 *     }
 *

@GwtCompatible(emulated = true)
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

      implements Serializable {

    private final Class<T> enumClass;

    StringConverter(Class<T> enumClass) {
      this.enumClass = checkNotNull(enumClass);
    }

    @Override
    protected T doForward(String value) {
      return Enum.valueOf(enumClass, value);
    }

    @Override
    protected String doBackward(T enumValue) {
      return enumValue.name();
    }

    @Override

      implements Serializable {

    private final Class<T> enumClass;

    StringConverter(Class<T> enumClass) {
      this.enumClass = checkNotNull(enumClass);
    }

    @Override
    protected T doForward(String value) {
      return Enum.valueOf(enumClass, value);
    }

    @Override
    protected String doBackward(T enumValue) {
      return enumValue.name();
    }

    @Override

      this.sourceFormat = checkNotNull(sourceFormat);
      this.targetFormat = checkNotNull(targetFormat);
    }

    @Override
    protected String doForward(String s) {
      return sourceFormat.to(targetFormat, s);
    }

    @Override
    protected String doBackward(String s) {
      return targetFormat.to(sourceFormat, s);
    }

    @Override

      this.sourceFormat = checkNotNull(sourceFormat);
      this.targetFormat = checkNotNull(targetFormat);
    }

    @Override
    protected String doForward(String s) {
      return sourceFormat.to(targetFormat, s);
    }

    @Override
    protected String doBackward(String s) {
      return targetFormat.to(sourceFormat, s);
    }

    @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

  }

  private <F, T> Converter<F, T> defaultConverter(
      final TypeToken<F> convertFromType, final TypeToken<T> convertToType) {
    return new Converter<F, T>() {
      @Override
      protected T doForward(F a) {
        return doConvert(convertToType);
      }

      @Override
      protected F doBackward(T b) {
        return doConvert(convertFromType);
      }

  }

  private <F, T> Converter<F, T> defaultConverter(
      final TypeToken<F> convertFromType, final TypeToken<T> convertToType) {
    return new Converter<F, T>() {
      @Override
      protected T doForward(F a) {
        return doConvert(convertToType);
      }

      @Override
      protected F doBackward(T b) {
        return doConvert(convertFromType);
      }