gistfile1.scala

package com.matygo.validation
import com.matygo.validation.validators.Validator
import com.matygo.validation.validators.StringLengthValidatorFactory

class TestObject(val someString: String, var someString2: String) extends Validatable[TestObject] {
    validates(
        lengthOfString(_.someString, 1, 5),
        lengthOfString(_.someString2, 1, 5))
}

object Test extends Application {
    val test = new TestObject("Vest", "Vest")
    println(test.validate(test))
    test.someString2 = "Vest one two three"
    println(test.validate(test))
}


/// --- 
trait Validatable[A] extends StringLengthValidatorFactory[A]{
    
    var validators: List[Validator[A, _]] = Nil

    def addValidator(validator: Validator[A, _]) = validators :+ validator

    def validate(a:A) = validators.forall(_.isValid(a))

    def validates(toAdd: Validator[A, _]*) = validators = toAdd.toList ::: validators
}

package com.matygo.validation.validators

abstract class Validator[V, T] {
	def accessor:((V => T))
    def isValid(validatable:V):Boolean
}

package com.matygo.validation.validators

class StringLengthValidator[V](val accessor:(V => String), val min: Int, val max: Int) extends Validator[V, String] {
    def isValid(validatable:V)= {
        val string = accessor(validatable)
        val length = string.length()
        println("Validates: " + string);
        length >= min && length <= max
    }
}

trait StringLengthValidatorFactory[A] {
    def lengthOfString(accessor:(A => String), min: Int, max: Int) = new StringLengthValidator[A](accessor, min, max)
    def lengthOfStringIsAtLeast(accessor:(A => String), min: Int) = new StringLengthValidator[A](accessor, min, Integer.MAX_VALUE)
    def lengthOfStringIsAtMost(accessor:(A => String), max: Int) = new StringLengthValidator[A](accessor, 0, max)
}