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
5. Track State ? How Do We
6. Booleans, Constants, Strings
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
30. patrick.seda@colligovox.com linkedin.com/in/patrickseda speakerdeck.com/pxtrick podcast: techmatters.fm Patrick Seda @pxtrick