Rules

In formconductor library, validation rules can be applied using kotlin @Annotations. Rules can only be applied to specified type of properties and can be stacked to apply multiple rules.

Supported Rule Annotations

Fields can be annotated with built-in validators to apply a validation rule to it.

info

Every field without a specific @Optional annotation is marked as Required/Mandatory by default.

Annotation	Rule	Type	Description
@EmailAddress	EmailAddressRule	String	Validates email address using the built-in regex pattern
@MinLength(value)	MinLengthRule	String	Minimum Length of the string
@MaxLength(value)	MaxLengthRule	String	Maximum Length of the string
@WebUrl(httpRequired)	WebUrlRule	String	Validates a Web Url
@IntegerRange(min,max)	IntegerRangeRule	Integer	Validates an Integer to be within range
@FloatRange(min,max)	FloatRangeRule	Float	Validates a Float to be within range
@IsChecked	IsCheckedRule	Boolean	Validates a Boolean to be true
@Optional	-	Any	Marks the field as an optional field

Custom Annotations

If you ever feel the need to create your own validation rules, the library allows you to do just that using the following annotations.

Annotation	Description
@FieldValidation(type,rule)	You can use this annotation to create your own Validation annotations
@DynamicOptional(evaluator)	You can use this annotation to evaluate the optional flag dynamically

Please check out the full guide on custom validations here

Manual Validation using built-in rules

Sometimes, you just need to validate a field value manuall and don't want to build an entire form for that. Or maybe, you want to reuse the validation rules from the library or the ones you've created. In such cases, you can take advantage of the ValidationRule instances of the library.

Using built-in rules

etProfilePage.doAfterTextChanged { input ->
    val result = WebUrlRule.validate(input, WebUrl(httpRequired = false))
    if (result is FieldResult.Success) {
        ...
        }
    else {
        ...
    }
}

Using custom rules

object FutureDateRule: StatelessValidationRule<LocalDate, FutureDate> {
    override fun validiate(input: LocalDate, options: FutureDate): FieldResult {
        if (input.isBefore(LocalDate.now())) {
            return FieldResult.Success
        } else {
            return FieldResult.Error("Date must be a future date", this)
        }
    }
}

// Call site
val date = calendarDialog.requestDate()
val result = FutureDateRule.validate(date, FutureDate())