@Udf
  public boolean check(@UdfParameter(description = "The input JSON string") final String input) {
    if (input == null) {
      return false;
    }

    try {
      return !UdfJsonMapper.parseJson(input).isMissingNode();
    } catch (KsqlFunctionException e) {
      return false;
    }
  }
@Test
  public void shouldInterpretArray() {
    assertTrue(udf.check("[1, 2, 3]"));
  }