Is this a bad way to handle a String DateTime Constraint?

Question

I created my own custom annotation. It basically tries to parse a String into LocalDateTime while following a custom pattern.

Here is the annotation:

@Documented
@Constraint(validatedBy = ValidateDateStringImpl.class)
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ValidateDateString {
    String message() default "Invalid date-time format";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
}

Here is the Validation Logic:

@Slf4j
public class ValidateDateStringImpl implements ConstraintValidator<ValidateDateString, String> {

    private  DateTimeFormatter dateTimeFormatter;

    @Override
    public void initialize(ValidateDateString constraintAnnotation) {
        dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSSz");
    }

    @Override
    public boolean isValid(String dateString, ConstraintValidatorContext context) {
        try{
            LocalDateTime.parse(dateString,dateTimeFormatter);
        }
        catch (DateTimeParseException ex){
            log.info(String.valueOf(ex));
            return false;
        }
        return true;
    }
}

Here is where the annotation is being used:

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class Foo{

    @NotBlank
    @ValidateDateString
    private String fooDateTime;

}

Is this a good approach, or are there some better alternatives. Thanks in advance!

Answer 1

I would expect

def do_something
  self.class.helper_methods
end

to return the value from the class variable.