Most applications we build are web-based. To get a feel for the current state of rich client applications, this session’s speaker and his colleagues decided to rebuild a Lego train front end with the NetBeans RCP. The Lego train is equipped with a Raspberry Pi, camera, wireless dongle, infrared transmitter, speaker, RFID reader, and battery pack. There are also automated switch tracks and cameras, again with the help of Raspberry Pi’s. To control the train and other parts, they built an actor-based application with Scala, Akka, Akka HTTP, and the NetBeans RCP. The presentation explains how you can build this yourself; describes their NetBeans RCP experiences and challenges; and, of course, includes a live demo.

1. USING NETBEANS RCP TO
CONTROLYOUR LEGO [CON1702]
Johan Janssen, Info Support @johanjanssen42

2. Disclaimer:
No Lego was harmed beyond
repair during the project.

3. CONTENT
 Why?
 Getting started
 Architecture
 Actors
 Remote actors
 Shared protocol
 HTTP vs Actors
 Conclusion
 Challenges
 Questions

4. WHY?

5. Why?

7. GETTING STARTED

8. MINIMAL INGREDIENTS FOR 1TRAIN
ABOUT € 50
Raspberry Pi A+ / Raspberry Pi Zero
Wifi dongle
EDUP Ultra-Mini Nano USB 2.0 802.11n
USB battery pack
Anker® 2. Gen Astro Mini 3200mAh
Infrared transmitter
Keyes 38KHz IR InfraredTransmitter Module for
Arduino

10. COMPARISON
Idle (mA) Memory (MB) CPU (Mhz) Size (mm)
RPi A+ 100 256 700 65 *56
RPi Zero 100 512 1000 65 * 30
RPi B+ 200 512 700 85 *56
RPi 2 B 230 1024 4*900 85 *56
Odroid C1 325 1024 4*1500 85 *56
Particle
Photon
80-100 128KB 120 38 * 21

11. ARCHITECTURE

12. Architecture

13. LTCC
(Angular)
LTCC
(Java)
DeviceControl
(Java)
Infrared
(C and LIRC)
RFID
(C)
SwitchControl
(Java)
Servo
(Python)
RPi-Cam-Web-
Interface
(C)

14. LTCC
(Angular)
LTCC
(Scala/Akka)
DeviceControl
(Scala/Akka)
Infrared
(C and LIRC)
RFID
(C)
SwitchControl
(Scala/Akka)
Servo
(Python)
Leds with Photon
(C)
RPi-Cam-Web-
Interface
(C)

15. LTCC
(NetBeans)
LTCC
(Scala/Akka)
DeviceControl
(Scala/Akka)
Infrared
(C and LIRC)
RFID
(C)
SwitchControl
(Scala/Akka)
Servo
(Python)
Leds with Photon
(C)
RPi-Cam-Web-
Interface
(C)

16. LTCC (Laptop / Pi)
LegoTrain
SwitchControl (Pi) Camera (Pi)
Device
Control
(Pi)

17. Original
controls

18. Infrared

19. Sound

21. Camera

23. Switches

27. LTCC APPLICATION

28. LTCC NETBEANS APPLICATION

29. NETBEANS DISADVANTAGES

33. NETBEANS ADVANTAGES

39. ACTORS

40. AKKA ACTORS
class Worker extends Actor {
def receive = {
case x =>
println(x)
}
}
val system = ActorSystem("ExampleActorSystem")
val workerActorRef = system.actorOf(Props[Worker])
workerActorRef ! "Hello conference"

41. REMOTE ACTORS

43. AKKA REMOTE ACTOR CALL
val workerActorRef =
system.actorOf(Props[Worker])
val workerActorRef =
system.actorSelection("akka.tcp://
ExampleActorSystem@127.0.0.1:9005
/user/workerActor")

44. AKKA REMOTE ACTOR CONFIGURATION
akka {
actor {
provider = "akka.remote.RemoteActorRefProvider"
}
remote {
enabled-transports = ["akka.remote.netty.tcp"]
netty.tcp {
hostname = "127.0.0.1"
port = 9002
}
}
}

45. SHARED PROTOCOL

46. Actor on
JVM 1
Actor on
JVM 2
Messages

47. Actor on
laptop
Musicservice
Actor on
Raspberry PiPlay
message
CONCRETE EXAMPLE

48. Server
application
MessageProtocol
Raspberry Pi
application

49. EXAMPLE MESSAGE
object MusicServiceMessage {
case class Play(filename: String)
case class MusicList(filenames: List[Song])
}

50. MESSAGE USED BY APPLICATION
val actorRef = context.actorSelection(
"akka.tcp://[Actorsystem]@
[IP]:[port]/user/musicservice")
actorRef !
[packagename].MusicServiceMessage.Play(filename)

51. HTTP VS REMOTE ACTOR

52. ADVANTAGES REMOTE ACTORS
 No converting to JSON/SOAP
 More natural programming
 Concurrent on default
 Built-in load balancer
 Built-in circuit breaker

53. ADVANTAGES HTTP
 Indepedent of technology
 Loosely coupled

54. FAT JAR (SBT ASSEMBLY) IN MB
0
5
10
15
20
25
Local actor Remote actor Akka HTTP Spring boot

55. GATLING

56. class ExampleSimulation extends Simulation {
val scn = scenario("My scenario").repeat(100) {
exec(
http("Ping")
.get("http://localhost:8080/ping")
.check(status.is(200))
).pause(100 millisecond) // Optional
}
setUp(scn.inject(
rampUsers(1000) over (10 seconds) // Changing
))
}

57. PERFORMANCETEST SETUP
JVM 1
Akka HTTP
HTTP: /ping
pong JVM 2
Akka HTTP
HTTP: /pong
pong
JVM 1
Akka HTTP
HTTP: /ping
pong JVM 2
Akka remote actor
Akka over TCP: pong
pong

58. 0
20
40
60
80
100
120
50 50 no pause 500 500 no pause 1000 1000 no pause
Mean response time (ms)
Akka HTTP Remote actor

59. 0
100
200
300
400
500
600
700
800
900
50 50 no pause 500 500 no pause 1000 1000 no pause
Max response time (ms)
Akka HTTP Remote actor

60. 0
50
100
150
200
250
300
350
50 50 no pause 500 500 no pause 1000 1000 no pause
99 percentile (ms)
Akka HTTP Remote actor

61. GRADUATION STUDENT
REST could handle around 600 users
Remote actors probably around 3300 users

62. REST is dead,
long live remote actors!
- Johan Janssen

64. 0
5
10
15
20
25
30
50 50 no pause 500 500 no pause 1000 1000 no pause
Mean response time (ms)
Remote actor Spring boot

65. 0
100
200
300
400
500
600
700
800
900
50 50 no pause 500 500 no pause 1000 1000 no pause
Max response time (ms)
Remote actor Spring boot

66. 0
20
40
60
80
100
120
140
160
50 50 no pause 500 500 no pause 1000 1000 no pause
99 percentile (ms)
Remote actor Spring boot

67. Challenges

78. CONCLUSION

79. CONCLUSION

80. The best part!!

81. QUESTIONS?
Johan Janssen, Info Support
@johanjanssen42