I can haz no Futures?

You will learn how simple functional patterns can be used to make your business logic cleaner and more testable.

Asynchronous programming brings a lot of Futures to your code. Bad news is that they are not essential to what your application really does… You end up with Futures of assertions in your unit tests or, even worse, with Await or expectNoMsg calls.

This is a live coding talk. First I will code an application using Futures in both business logic and unit tests. Then I will get rid of Futures without losing asynchronicity. In the second part, I will do a step by step refactoring of a simple Akka actor system. In both cases I will use typeclasses from Cats library.

Transcript

1. I can haz no
   Futures?
   Michał Płachta
   @miciek
   

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2. The Journey Ahead of Us
   WHY?
   REFACTORING
   ACTOR SYSTEM
   REFACTORING
   ADD FUNCTION
   

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3. Complexity is the
   root cause of the
   vast majority of
   problems with
   software today.
   “
   

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4. Essential
   ▪ The “heart” of your
   system
   ▪ The WHAT
   Complexity
   Accidental
   ▪ The least important part
   of your system
   ▪ The HOW and WHEN
   

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5. Future[Option[Customer]]
   Here’s a return type of a function in a CRM system...
   QUIZ
   Accidental Complexity Essential Complexity
   

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6. “
   We have to keep it
   crisp, disentangled,
   and simple if we
   refused to be crushed
   by the complexities of
   our own making…
   Portrait by Hamilton Richards - manuscripts of Edsger W. Dijkstra, University Texas at Austin, CC BY-SA
   3.0, https://commons.wikimedia.org/w/index.php?curid=4204157
   

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7. Managing
   Complexity
   Live coding examples
   

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8. def add(Int, Future[Int]): Future[Int]
   Let’s start with a very simple case...
   LIVE CODING #1
   

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9. Palindrome
   Checker
   Actor
   Length
   Calculator
   Actor
   String Stats
   Calculator
   Actor
   def stringStats(String): Future[StringStats]
   External Stuff We Can’t Touch
   LIVE CODING #2
   

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10. ANY QUESTIONS?
    @miciek
    www.michalplachta.com/contact
    Thanks!
    

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