Kotlin ValueObject by delegated properties

Main.kt

import java.security.InvalidParameterException
import java.util.regex.Matcher
import java.util.regex.Pattern
import kotlin.properties.ReadOnlyProperty
import kotlin.reflect.KProperty

//Domain entities with E-mail property
class Client(email: String) {
    val email: String by EmailDelegated(email)
}

class User(email: String) {
    val email: String by EmailDelegated(email)
}

//E-mail Value Object
class EmailDelegated<T>(private var email: String) : ReadOnlyProperty<T, String> {

    init {
        validate(email)
    }

    override fun getValue(thisRef: T, property: KProperty<*>) = email

    private fun validate(value: String) {

        val pattern = Pattern.compile("^([a-zA-Z0-9_.-])+@([a-zA-Z0-9_.-])+\\.([a-zA-Z])+([a-zA-Z])+")
        val matcher: Matcher = pattern.matcher(value)

        if(!matcher.matches()) //Change to domain notification =D
            throw InvalidParameterException("Invalid e-mail!")
    }
}

fun main() {
    val client = Client("silva.jd8@gmail.com")
    println(client.email)

    val user = User("silva.jd8@gmail.") //Throw exception
    println(user.email)
}