Micronaut custom validation constraints, write custom message depending on the value

Question

Is there a way in Micronaut to define custom message for validation in Micronaut.

Here is my code :

This is the annotation class :

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
@Constraint(validatedBy = [])
@Documented
@interface CheckDecimal {
    String message() default "Invalid Decimal ({validatedValue})";

    double minimum()

    double maximum()

    int integerLength()

    int decimalLength()
}

This is my validation factory :

import io.micronaut.context.annotation.Factory
import io.micronaut.core.annotation.AnnotationValue
import io.micronaut.validation.validator.constraints.ConstraintValidator
import io.micronaut.validation.validator.constraints.ConstraintValidatorContext
import powehr.pandore.mn.validation.CheckDecimal

import javax.inject.Singleton

@Factory
class ValidatorFactory {

    @Singleton
    ConstraintValidator<CheckDecimal, Double> checkDecimalValidator() {
        return { Double value,
                 AnnotationValue<CheckDecimal> annotation,
                 ConstraintValidatorContext context ->

            final parameters = annotation.convertibleValues.asMap()
            final keySet = parameters.keySet()

            if(value == null) {
                return true
            }

            if(keySet.contains('minimum')) {
                double minimumValidator = parameters.get('minimum')
                if(value < minimumValidator) {
                    // Define specific constraint message here
                    return false
                }
            }

            if(keySet.contains('maximum')) {
                double maximumValidator = parameters.get('maximum')
                if(value > maximumValidator) {
                    // Define specific constraint message here
                    return false
                }
            }


            if(keySet.contains('integerLength')) {
                final integerLengthValidator = parameters.get('integerLength')
                final integerLength = value.toString().split(/\./)[0].length()

                if(integerLength > integerLengthValidator) {
                    // Define specific constraint message here
                    return false
                }
            }

            if(keySet.contains('decimalLength')) {
                final decimalLengthValidator = parameters.get('decimalLength')
                final decimalLength = value.toString().split(/\./)[1].length()

                if(decimalLength > decimalLengthValidator) {
                    // Define specific constraint message here
                    return false
                }
            }

            return true
        } as ConstraintValidator<CheckDecimal, Double>
    }
}

And i use my constraint like that :

 @CheckDecimal(minimum = -1.0d, maximum = 97.0d, integerLength = 2, decimalLength = 4)

I'd like to be able to write specific message in each case of constraint violation. The context doesn't seem to offer many possibility here.

Is there a way to define specific message validation in checkDecimalValidator() ?

Answer 1

No there isn't. The validation API this is modeled after is designed so that each validation has its own annotation.

You should have be able to use the existing annotations for all cases though.

minimum = -1.0d is equivalent to @DecimalMin("1.0")

maximum = 97.0d is equivalent to @DecimalMax("97.0")

integerLength = 2, decimalLength = 4 is equivalent to @Digits(integer = 2, fraction = 4)