Moshi's Kotlin CodeGen

Learn how to leverage Moshi’s Kotlin codegen so your data model can be immutable and quickly parsed reflection free. I’ll discuss why this is important to us as developers, integration details, and how Moshi implemented this feature!

Transcript

1. Moshi Code Gen Brian Plummer - Nike
2. Moshi Code Gen A Love Story Brian Plummer - Nike
3. Reflection Free Parsing & Immutable Data Model Moshi Code Gen =
4. ELI5 Definitions
6. Immutable
7. Immutable Not Mutable
8. Immutable Not Mutable Hard to change
10. Reflection Free
11. Reflection Free Not Dynamic
12. Reflection Free Not Dynamic Compiled
13. Why does this matter?
14. Mike’s first month at the New York Times Application startup time was horrible. He started digging and found some issues.
15. One big culprit was parsing a configuration file that we needed for Application start up
16. One big culprit was parsing a configuration file that we needed for Application start up Roughly 700ms wasted!
17. What was the issue? Why did it take so long?
18. What was the issue? Why did it take so long? Reflection!
19. How shall we fix this?
20. We could write our own type adapters How shall we fix this?
23. Annotation Processing
24. Annotation Processing •AutoValue
25. Annotation Processing •AutoValue •Immutables.org
26. Unfun stuff taken care of for us
27. Unfun stuff taken care of for us •toString()
28. Unfun stuff taken care of for us •toString() •equals()
29. Unfun stuff taken care of for us •toString() •equals() •hashCode()
30. Copy methods for mutate
31. Immutable Data Model
32. Immutable Data Model •Thread safety
33. Immutable Data Model •Thread safety •Reduced Complexity
34. Immutable Data Model •Thread safety •Reduced Complexity •No more bugs caused by mutation
35. Reflection free type adapters
36. All was well!
37. Kotlin came and we have data classes
39. Data classes give us most of what we needed
40. Data classes give us most of what we needed
41. Data classes give us most of what we needed •Unfun methods
42. Data classes give us most of what we needed •Unfun methods •Copy methods
43. Data classes give us most of what we needed •Unfun methods •Copy methods •Immutability
44. Data classes give us most of what we needed •Unfun methods •Copy methods •Immutability •Reflection free parsing
45. Moshi to the rescue!
46. data class Book ( val title: String?, val authors: List<Author>, val isbn: String )
47. @JsonClass(generateAdapter = true) data class Book ( val title: String?, val authors: List<Author>, val isbn: String )
48. That’s it!
49. Really really it..besides adding it as a dependency in gradle of course! That’s it!
50. implementation "com.squareup.moshi:moshi:$moshi_version" kapt("com.squareup.moshi:moshi-kotlin-codegen:$moshi_version") Really really it..besides adding it as a dependency in gradle of course!
51. That sounds too good to be true.
52. How does it work? That sounds too good to be true.
53. Annotation processing How does it work?
54. Type adapter resolves at runtime so you don’t have to do anything else
55. Uses reflection once to lookup, caches it for use. Good across modules!
56. gson? It’s time
57. Moshi is the way forward
58. http://blog.nimbledroid.com/ 2016/02/23/slow-Android- reflection.html
59. https://medium.com/ @ZacSweers/exploring-moshis- kotlin-code-gen-dec09d72de5e
60. https:// open.blogs.nytimes.com/ author/mike-nakhimovich/