Architecting Your Project with a Finite-State Machine

Transcript

1. Architecting Your Project with a Finite-State Machine DEVNEXUS Atlanta –

   February 24, 2017

2. Patrick Seda @pxtrick - CTO of Colligo Vox - Mobile/Technology

   Solutions Consulting - 25+ Years as a Software Professional - Apps: Enterprise to Children’s games
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5. Track State ? How Do We

6. Booleans, Constants, Strings

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8. Finite-State Machine!

9. -  Abstract machine -  Can be in exactly one of

   a finite number of states at a time -  State changes via input events -  Transitions -  Module finite-state machine

10. finite-state machine Door Closed Door Open open close

11. Configuring The FSM

12. configuring // JSON example ... var config = { states:

    { ‘DoorClosed’: { events: { ‘open’: { toState: ‘DoorOpen’} } }, ‘DoorOpen’: { events: { ‘close’: { toState: ‘DoorClosed’} } } }, startState: ‘DoorClosed’ };

13. Home Security System! Let’s Design a

14. a security system

15. A Honeywell Security System

16. Armed Stay Armed Away Armed Max Exit Delay? Entry Delay?

    Motion? No Yes Yes Yes Yes No No Yes Yes Armed Instant No No No a honeywell system

17. “Armed Away” a honeywell system

18. “Armed Max” a honeywell system

19. “Armed Stay” a honeywell system

20. “Armed Instant” a honeywell system

21. a honeywell system

22. The State Pattern

23. state pattern •  Separates interface from implementation •  Enables interchangeable

    behavior •  Perfect for a state machine! Context State State A State B handle() handle() handle()

24. state pattern Handler State Armed Disarmed handle() handle() handle() Alarming

    handle() for our home security system …

25. The System In Motion

26. Architectural Big Picture

27. big picture Event Handler Disarmed State State State Armed FSM

28. big picture Visual Status Audible Status Emergency Services Web Backend

    Keypad Sensors
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30. patrick.seda@colligovox.com linkedin.com/in/patrickseda speakerdeck.com/pxtrick podcast: techmatters.fm Patrick Seda @pxtrick