factory-function-approach-3.kt

class PhoneNumberScreen(
    private val phoneNumber: PhoneNumber
) {

    init {
        require(phoneNumber.value.isNotEmpty()) { "cannot handle invalid phone number" }
    }

    fun render() {
        println("Phone number: ${phoneNumber.value}")
    }
}

fun main() {
    val contact = Contact(PhoneNumber("12345"))
    show(contact.phoneNumber) // "Phone number: 12345"

    val contactWithInvalidPhoneNumber = Contact(PhoneNumber(""))
    show(contactWithInvalidPhoneNumber.phoneNumber) // prints nothing
}

private fun show(phoneNumber: PhoneNumber) {
    try {
        val phoneNumberScreen = PhoneNumberScreen(phoneNumber)
        phoneNumberScreen.render()
    } catch (ex: IllegalArgumentException) {

    }
}