iboss-ptk

// Create type alias for the function
typealias MessageCreatorFactory = (PhoneNumber, String, String) -> MessageCreator

@Service
class NotificationService(
        private val restClient: TwilioRestClient,
        private val secretRepository: SecretRepository
) {
    fun notify(
            notificationRequest: NotificationRequest,

iboss-ptk

@Service
class NotificationService(
        private val restClient: TwilioRestClient,
        private val secretRepository: SecretRepository
) {
    fun notify(
            notificationRequest: NotificationRequest,
            // Now we know its type
            creator: (PhoneNumber, String, String) -> MessageCreator
    ): NotificationResponse {

iboss-ptk

class Message {
  // ...
  public static MessageCreator creator(final com.twilio.type.PhoneNumber to,
                                       final String messagingServiceSid,
                                       final String body) {
    return new MessageCreator(to, messagingServiceSid, body);
  }
}

iboss-ptk

@Service
class NotificationService(
        private val restClient: TwilioRestClient,
        private val secretRepository: SecretRepository
) {
    fun notify(
            notificationRequest: NotificationRequest,
            // Inject creator function as an argument
            creator: ????
    ): NotificationResponse {

iboss-ptk

// while executing in Spring context.
// Dependencies in constructor are injected by Spring

@Service
class NotificationService(
        private val restClient: TwilioRestClient,
        private val secretRepository: SecretRepository
) {
    fun notify(notificationRequest: NotificationRequest): NotificationResponse {
        val (countryCode, phoneNumber, text) = notificationRequest

iboss-ptk

@Service
class OtpLoginService(
        private val otpService: OtpService,
        private val otpAuthProvider: OtpAuthProvider
) {
    fun login(otpVerificationRequest: OtpVerificationRequest): VerificationResult {
        // ***** calls static method
        val securityContext = SecurityContextHolder.getContext()

        val verification = otpService.verifyOTP(otpVerificationRequest)

iboss-ptk

data Maybe a = Just a | Nothing

iboss-ptk

fmap length Nothing
-- Nothing

fmap length (Just "Hello")
-- Just 5

iboss-ptk

[1,2,3,4].map(x => x + 1)
// [2,3,4,5]

iboss-ptk

fmap (+1) [1,2,3,4]
-- [2,3,4,5]