Basic-Usage.md

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Getting Started < Basic Usage > Functional Validators

Consider the following case class.

case class Person(firstName: String,
                  lastName: String,
                  age: Int,
                  married: Boolean,
                  hasJob: Boolean,
                  notes: Option[String])

SimpleValidator style

To validate instances of the class, create a validator that extends SimpleValidator[A] where A is the type being validated.

import com.magaran.svalidator.validation.simple.SimpleValidator

class PersonValidator extends SimpleValidator[Person] {

  override def validate(using instance: Person) = WithRules(
    For(_.firstName) ForField "firstName"
      must (_.nonEmpty) withMessage "First name is required"
      must (_.length <= 32) withMessage "Must have 32 characters or less",

    For(_.lastName) ForField "lastName"
      must (_.nonEmpty) withMessage "Last name is required"
      must (_.length <= 32) withMessage "Must have 32 characters or less",

    For(_.age) ForField "age"
      must (_ >= 0) withMessage "Must be a positive number"
  )
}

WithRules receives a varargs list of RuleBuilder instances. Each chain starts with For and must set a field name using ForField. Use must/mustNot and end each rule with withMessage. If a rule fails, further rules in the same chain will not be evaluated.

If you need to validate an arbitrary expression (not a simple property selector), use RuleFor instead of For and manually provide the field name.

override def validate(using instance: Person) = WithRules(
  RuleFor(p => p.firstName + " " + p.lastName) ForField "fullName"
    must (_.length <= 64) withMessage "Full name is too long"
)

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