Scala pattern matching always goes to default case - scala

Question

First of all, I'm relatively new to scala.
Consider the following simple class NullLogService which logs results to console.
package services
import akka.actor._
import com.amazonaws.services.simpleemail.model.SendRawEmailResult
import model.Email
import scala.util.Try
object NullLogService {
case class Log(email: Email, amazonResult: Try[_])
case class LogError(email: Email, amazonException: Try[_])
}
class NullLogService extends Actor {
import NullLogService._
def receive = {
case Log(email, amazonResult) => println("Email to: " + email.to + ". AmazonResultSucess:" + amazonResult.isSuccess.toString + ". AmazonResult: " + amazonResult.get.toString)
case LogError(email, amazonException) => println("Error: Email to: " + email.to + ". AmazonException:" + amazonException.get.toString)
case default#_ => println("Default case: "+default.toString)
}
}
It prints Default case: Log(TO:email#email.com,Success({MessageId: Fake_Sent_OK})) always.
I don't know what is happening, because the types are the same (Log(Email,Try(_))) ! It should go to the "Log" case but always fall to the default case!
Driving me crazy.
Code involved
Main class:
import java.io.File
import java.util.concurrent.TimeUnit
import akka.actor.SupervisorStrategy.Resume
import akka.actor._
import akka.routing.RoundRobinPool
import akka.util.Timeout
import com.thenewmotion.akka.rabbitmq._
import com.typesafe.config.{ConfigFactory, ConfigParseOptions}
import model.Email
import services.EmailService.EmailInfo
import services.{EmailService, LogService, NullLogService}
import utils.StringUtils
import scala.concurrent.duration.Duration
object Main extends App {
implicit val system = ActorSystem()
val emailServiceRef: ActorRef = system.actorOf(RoundRobinPool(rate).withSupervisorStrategy(supervisorStrategy).props(Props(new EmailService)), "emailWorkerPool")
val logServiceRef = system.actorOf(RoundRobinPool(1).props(Props(new NullLogService)), "logWorker")
val email = new Email(stringMap.apply("USEREMAIL"), stringMap.apply("REPLYTO"), stringMap.apply("SUBJECT"), stringMap.apply("BODY"), unsubscribeURL)
emailServiceRef ! EmailInfo(email, logServiceRef)
}
EmailService:
package services
import akka.actor._
import com.amazonaws.services.simpleemail.model.SendRawEmailResult
import model.Email
import services.LogService.{Log, LogError}
object EmailService {
case class EmailInfo(email: Email, logServiceRef: ActorRef)
}
class EmailService extends Actor {
import EmailService._
def receive = {
case EmailInfo(email, logServiceRef) =>
val emailResult = new SendRawEmailResult
emailResult.setMessageId("Fake_Sent_OK" )
val amazonResult = Try( emailResult )
logServiceRef ! Log(email, amazonResult)
}
}

Answer 1

Presumably you haven't removed LogService.Log and LogService.LogError, or else you would have gotten a compilation error for EmailService. In this case NullLogService shouldn't define its own messages, but use LogService's ones:
package services
import akka.actor._
import com.amazonaws.services.simpleemail.model.SendRawEmailResult
import model.Email
import scala.util.Try
import LogService.{Log, LogError}
// no object NullLogService unless you need it for something else
class NullLogService extends Actor {
def receive = {
case Log(email, amazonResult) => println("Email to: " + email.to + ". AmazonResultSucess:" + amazonResult.isSuccess.toString + ". AmazonResult: " + amazonResult.get.toString)
case LogError(email, amazonException) => println("Error: Email to: " + email.to + ". AmazonException:" + amazonException.get.toString)
case default#_ => println("Default case: "+default.toString)
}
}
Then you can switch between different services which use the same protocol (say, NullLogService, Slf4jLogService, InMemoryLogService) without changing the imports every time.

Answer 2

Found the error. I had to change the logger class I was importing.
I use NullLogService now, not LogService.
package services
import akka.actor._
import com.amazonaws.services.simpleemail.model.SendRawEmailResult
import model.Email
//Change this --> import services.LogService.{Log, LogError} <---
//To the class you are using --v
import services.NullLogService.{Log, LogError}
object EmailService {
case class EmailInfo(email: Email, logServiceRef: ActorRef)
}
class EmailService extends Actor {
import EmailService._
def receive = {
case EmailInfo(email, logServiceRef) =>
val emailResult = new SendRawEmailResult
emailResult.setMessageId("Fake_Sent_OK" )
val amazonResult = Try( emailResult )
logServiceRef ! Log(email, amazonResult)
}
}
It is weird because there was no runtime errors (like "NullLogService not imported")