Introduction to The Flow Factory Design Pattern
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The document introduces the Flow Factory Design Pattern, emphasizing principles of object-oriented design such as programming to interfaces and ensuring loosely-coupled designs. It outlines the structure of flow execution via an inversion of control model with two passes for processing steps and finalizing actions. Additionally, it provides examples of logical interfaces and invokes flows, along with resources for further learning.
Introduction to The Flow Factory Design Pattern
- 1. Introduction to the Flow Factory Design Pattern Developers Track Adam Purkiss, MondayCall Solutions, Principal Architect @apurkiss adampurkiss.com
- 2. Learning the hard way… ENTER COMMAND: GO NORTH ■
- 3. Learning the hard way… ENTER COMMAND: ■
- 4. Object-oriented design patterns ▪ Program to an interface, not an implementation ▪ Strive for loosely-coupled designs ▪ Encapsulate what varies ▪ Remember the open-closed principle
- 7. The problem Course Complete In international registry? In US registry? Update Salesforce N Create profile Y Update profile N Y Update profile Done Welcome email
- 8. The problem grew Course Complete In rewards program? In US registry? Update Salesforce N Create profile Y Update profile Y Add rewards points N In international registry? N Y Update profile Done Welcome email Rewards email
- 10. Deferring DML and email Course Complete In rewards program? In US registry? Update Salesforce N Create profile Y Update profile Y Add rewards points N In international registry? N Y Update profile Done Welcome email Rewards email
- 11. The Flow Factory ▪ Flow-specific inputs ▪ Executed steps collection ▪ Steps create & return next steps ▪ Inversion of Control ▪ Two pass execution ▪ Pass 1: Step.processStep() ▪ Pass 2: Step.finish()
- 12. Flow of the flow Pass 1 Step 1 Step 2 Step 3 Step 4 ▪Add self to list ▪Process work ▪Create next ▪… ▪… ▪… ▪… ▪... ▪… ▪... ▪… ▪Return null Step 1 Step 2 Step 3 Step 4 ▪Final processing ▪… ▪… ▪… Pass 2 (DML)
- 13. Flow of the flow Pass 1 Step 1 Step 2 Step 3 Step 4 processStep() processStep() processStep() processStep() Step 1 Step 2 Step 3 Step 4 finish() finish() finish() finish() Pass 2 (DML)
- 14. Logical interfaces ▪ FlowStep (create / process / finish) ▪ FlowState (inputs / aggregate) ▪ FlowParent (process loop / finish loop)
- 15. FlowStep 1) Next step / step name 2) Process step / finish 3) Create instance 1 2 3
- 16. FlowStep variation ▪ Create dynamic instance
- 17. FlowState 1) Steps aggregate in parent list 2) Flow-specific inputs in subclass 1 2
- 18. FlowParent 1) Provide initial step & state 2) Main loop (pass 1) 3) Finish loop (pass 2) 1 2 3
- 19. Invoking a flow example 1) Subclass FlowParent / processWork() 2) Invoke flow 1 2
- 20. Pass 1 processStep() Course Nothing Complete Update Salesforce In rewards program? processStep() Callout In US registry? processStep() Callout N Create profile Y Update profile Y Add rewards points N In international registry? processStep() N Callout Y Update profile Done Welcome email Rewards email
- 21. Pass 2 finish() Course Update Salesforce (DML)Complete In US registry? Update Salesforce Save callout response Send email N In international registry? finish() N Save callout response N finish() In rewards program? Create profile Y Update profile Y Add rewards finish() points Save callout response Send email Y Update profile Done Welcome email Rewards email
- 22. Demo
- 23. Resources GitHub: ▪https://github.com/apurkiss/course-complete Developerforce Wiki: ▪http://wiki.developerforce.com/page/The_Flow_Factory_Design_Pattern Pluralsight: Force.com Design Patterns - Part 2 ▪http://pluralsight.com/training/Courses/TableOfContents/forcedotcom-designpatterns-part2