@Udf
  public String decodeParam(
      @UdfParameter(description = "the value to decode") final String input) {
    if (input == null) {
      return null;
    }
    try {
      return URLDecoder.decode(input, UTF_8.name());
    } catch (final UnsupportedEncodingException e) {
      throw new KsqlFunctionException(
          "url_decode udf encountered an encoding exception while decoding: " + input, e);
    }
  }
@Test
  public void shouldDecodeEncodedValue() {
    assertThat(decodeUdf.decodeParam("%3Ffoo+%24bar"), equalTo("?foo $bar"));
  }