akka fsm talk given on Glassbeam

1. FINITESTATEMACHINES
(FSM)
WITHAKKAACTORS
WRITINGANDUNITTESTING'EM
"LIGHTNINGTALK"BYPRASANNAKUMAR

2. WHATISFSM?
whenaprogramisinastateSandan
eventEoccursthendoanactionAand
changetoanotherstateS1
Iftheabovesoundstootheoriticaltounderstand....

3. IMAGINEATRAFFICSIGNAL
hopeyoucouldunderstand!!!

4. WHYDOWENEEDFSM?
ATLEASTFORUS...
ModelandExecuteRules(weareusingit!!!)
Simulations
Automatabasedprogramming

5. WHYTHISPRESENTATION
IwanttolearnFSM

6. "FSM"FROMAKKAPERSPECTIVE
State
Data
MessagestotheactorisanalogoustoEvents
Actorabstractionitself
sealedtraitFSMSignal
caseclassSignalColorData
classSignalChangeFSMActorextendsActor
withFSM[FSMSignal,SignalColorData]{
.....
}

7. LET'SMODELFSM
//state-
sealedtraitFSMSignal
caseobjectRedSignalextendsFSMSignal
caseobjectYellowSignalextendsFSMSignal
caseobjectGreenSignalextendsFSMSignal
//data
caseclassSignalColorData
//event
caseobjectChangeSignal
caseobjectRetainSignal

8. ACTORCODE
classSignalChangeFSMActorextendsActorwithFSM[FSMSignal,SignalColorData]{
//initialstateofFSM
startWith(RedSignal,SignalColorData())
when(RedSignal){
caseEvent(ChangeSignal,_)=>goto(YellowSignal)
caseEvent(RetainSignal,_)=>stay
}
when(YellowSignal){
caseEvent(ChangeSignal,_)=>goto(GreenSignal)
caseEvent(RetainSignal,_)=> stay
}

9. CONTD...
when(GreenSignal){
caseEvent(ChangeSignal,_)=>goto(RedSignal)
caseEvent(RetainSignal,_)=> stay
}
onTransition{
caseRedSignal->YellowSignal=>println("Changingfromredtoyellowsignal-getr
caseYellowSignal->GreenSignal=>println("Changingfromyellowtogreensignal-w
caseGreenSignal->RedSignal=>println("Changingfromgreentoredsignal-stop!!
}
initialize
}

10. UNITTESTINGFSMACTORSWITH
classFSMActorTest(as:ActorSystem)extendsTestKit(as)
withImplicitSender
withWordSpecLike
withMatchers
withBeforeAndAfterAll{
//allourtestcases
}

11. valfsmRef=TestFSMRef(newSignalChangeFSMActor)
defthis()=this(ActorSystem("FSMActorSystem"))
"OursignalemulatingFSMActor"must{
"beredatinitialstage"in{
assert(fsmRef.stateName==RedSignal)
assert(fsmRef.stateData==SignalColorData())
}
"changetoyellowafterAlternateColoureventoccured"in{
fsmRef!ChangeSignal//sendaneventtoFSM
assert(fsmRef.stateName==YellowSignal)
assert(fsmRef.stateData==SignalColorData())
}
"changetogreenafterAlternateColoureventoccured"in{
fsmRef!ChangeSignal
assert(fsmRef.stateName==GreenSignal)
assert(fsmRef.stateData==SignalColorData())
}
"retainshouldnotchangethefsmstate"in{
fsmRef!RetainSignal
assert(fsmRef.stateName==GreenSignal)
assert(fsmRef.stateData==SignalColorData())
}
}
overridedefafterAll={
println("trafficisclearnow-obeytrafficrules")
}

12. SESSIONTAKEAWAY
Code:-https://github.com/prassee/FSMExperiment

13. HOWIMADETHISPRESENTATION?
HTML5
CSS3
Presentation:-reveal.js
Imagescourtesy:-googleimagesearch:)
ThispresentationisCCLlicensed-feelfreetomodify

14. THANKS:)