Coroutines and Asynchronous Programming (BlrKotlin)

Presented at BlrKotlin March Meetup (2019), this talks guids you through the basic concepts of Coroutines and how to use them for you asynchronous programming requirement in Android

Transcript

1. Rivu Chakraborty
   Coroutines & Asynchronous
   Programming
   1
   https://www.rivu.dev
   

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2. Rivu Chakraborty
   BYJU’S
   @rivuchakraborty
   Coroutines & Asynchronous
   Programming
   2
   https://www.rivu.dev
   

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3. Rivu Chakraborty
   BYJU’S
   @rivuchakraborty
   About Me
   ● Sr Software Engineer (Android) - BYJU’S
   ● Instructor - Caster.io
   ● Google Certified Associate Android Developer
   ● DroidJam Speaker
   ● Author - Reactive Programming in Kotlin
   ● Author - Functional Kotlin
   ● Author - Hands on Data Structures and Algorithms
   with Kotlin
   ● Author - Coroutines for Android Developers (WIP)
   3
   https://www.rivu.dev
   

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4. https://www.rivu.dev
   

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5. Books
   https://www.packtpub.com/a
   pplication-development/react
   ive-programming-kotlin
   https://www.packtpub.com/a
   pplication-development/funct
   ional-kotlin
   https://leanpub.com/coroutines-f
   or-android-developers
   Work in Progress
   https://www.packtpub.com/appl
   ication-development/hands-dat
   a-structures-and-algorithms-ko
   tlin
   

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6. Coroutines & Asynchronous
   Programming
   Async => Concurrency
   

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7. Coroutines & Asynchronous
   Programming
   Concurrency ⇏ Parallel
   

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8. Concurrency
   ● Ability to execute
   multiple code blocks
   at the same time
   @rivuchakraborty
   https://www.rivu.dev
   

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9. Concurrency
   ● Ability to execute
   multiple code blocks at
   the same time
   ● Not only for Android
   Developers
   @rivuchakraborty
   https://www.rivu.dev
   

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10. Concurrency
    ● Ability to execute multiple code
    blocks at the same time
    ● Not only for Android Developers
    ● JavaScript - Promise
    ● JVM, Android - Threads
    (Fibers)
    ● Native (LLVM) - Pure Kotlin
    @rivuchakraborty
    https://www.rivu.dev
    

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11. 11
    Concurrency in Android
    ● AsyncTask
    ● CompletableFuture
    ● Runnable / Thread (Custom Threadpool)
    ● Rx
    ● Counting...
    @rivuchakraborty
    https://www.rivu.dev
    

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12. 12
    Concurrency in Android
    ● Coroutines
    @rivuchakraborty
    https://www.rivu.dev
    Let’s you write non-blocking asynchronous code in your
    choice of Style - Sequentially, in Functional Style or whatever
    you prefer.
    

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13. Coroutines
    13
    @rivuchakraborty
    https://www.rivu.dev
    Light-Weight Threads
    Thread 1 Thread 2 Thread 3
    Coroutine 1 Coroutine 2 Coroutine 3
    With Coroutines, Threads are still used (for JVM).
    

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14. Coroutines
    14
    @rivuchakraborty
    https://www.rivu.dev
    Light-Weight Threads
    Thread 1 Thread 2 Thread 3
    Coroutine 1 Coroutine 2 C 3 C 4 C 5 C 6 C 7 C 8 C N
    But a single Thread (Fiber) can run multiple
    coroutines.
    

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15. Coroutines
    15
    @rivuchakraborty
    https://www.rivu.dev
    Easy to Use
    

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16. Suspension &
    Continuation
    Builders
    Suspending
    Functions
    Done
    Coroutines
    Components
    Scope &
    Dispatchers
    @rivuchakraborty
    https://www.rivu.dev
    16
    

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17. Coroutines
    17
    @rivuchakraborty
    https://www.rivu.dev
    Suspending vs
    Blocking
    

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18. 18
    @rivuchakraborty
    https://www.rivu.dev
    Suspending vs
    Blocking
    

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19. 19
    @rivuchakraborty
    https://www.rivu.dev
    Suspending vs
    Blocking
    

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20. Launch a Coroutine
    20
    @rivuchakraborty
    https://www.rivu.dev
    

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21. Get the Job done or cancel it,
    your choice. :)
    21
    @rivuchakraborty
    https://www.rivu.dev
    

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22. Compute Async(hrounously)
    22
    @rivuchakraborty
    https://www.rivu.dev
    

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23. Deferred
    23
    @rivuchakraborty
    https://www.rivu.dev
    ● Deferred
    Extends Job
    ● Wrapper
    around your
    data
    

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24. Suspending Function
    24
    @rivuchakraborty
    https://www.rivu.dev
    ● suspend is a
    Keyword in Kotlin
    

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25. Suspending Function
    25
    @rivuchakraborty
    https://www.rivu.dev
    ● suspend is a Keyword in
    Kotlin
    ● Compiler level
    restriction - can’t
    call suspend
    function outside
    CoroutineScope
    

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26. Suspending Function
    26
    @rivuchakraborty
    https://www.rivu.dev
    ● suspend is a Keyword in
    Kotlin
    ● Compiler level restriction -
    can’t call suspend function
    outside CoroutineScope
    ● Suspends
    execution of
    current coroutine,
    until the function is
    completed
    

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27. Coroutine Scope
    27
    @rivuchakraborty
    https://www.rivu.dev
    ● Container of
    CoroutineContext
    

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28. Coroutine Scope
    28
    @rivuchakraborty
    https://www.rivu.dev
    ● Container of
    CoroutineContext
    ● Every Coroutine
    Builder is an
    extension over
    CoroutineScope,
    and thus inherits its
    CoroutineContext
    

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29. Coroutine Scope
    29
    @rivuchakraborty
    https://www.rivu.dev
    ● Container of
    CoroutineContext
    ● Every Coroutine Builder is an
    extension over
    CoroutineScope, and thus
    inherits its CoroutineContext
    ● All Coroutines must
    be launched within
    a CoroutineScope
    

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30. Coroutine Scope
    30
    @rivuchakraborty
    https://www.rivu.dev
    

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31. Coroutine Context
    31
    @rivuchakraborty
    https://www.rivu.dev
    ● Holds key
    informations about
    the Coroutine such
    as Dispatcher /
    ThreadPool
    Configuration,
    Coroutine Name
    etc.
    

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32. Dispatchers
    32
    @rivuchakraborty
    https://www.rivu.dev
    ● Determines which Thread / ThreadPool, the
    coroutine will run on.
    

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33. Dispatchers
    33
    @rivuchakraborty
    https://www.rivu.dev
    ● Determines which Thread / ThreadPool, the coroutine will run on.
    ● Similar to the Rx Schedulers
    

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34. Let’s Build for
    Android
    

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35. Repository
    35
    @rivuchakraborty
    https://www.rivu.dev
    

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36. API (Retrofit)
    36
    @rivuchakraborty
    https://www.rivu.dev
    

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37. Activity
    37
    @rivuchakraborty
    https://www.rivu.dev
    

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38. Call it
    38
    @rivuchakraborty
    https://www.rivu.dev
    

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39. Handle Exception (Gracefully) :D
    39
    @rivuchakraborty
    https://www.rivu.dev
    

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40. Rivu Chakraborty, BYJU’S
    @rivuchakraborty
    https://www.rivu.dev
    Resources
    https://caster.io/courses/kotlin-co
    routines-fundamentals
    ● http://bit.ly/CodeLabCoroutines
    ● http://bit.ly/CoroutinesAndroid
    ● http://bit.ly/DroidCoroutines
    ● http://bit.ly/CoroutinesGuide
    40
    

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41. Thank you!
    41
    Rivu Chakraborty, BYJU’S
    @rivuchakraborty
    https://www.rivu.dev
    

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