Migrate Enterprise Apps to Kotlin

Transcript

1. M I G R AT I N G E N T E R P R I S E A P P S T O K O T L I N ! @ A M A H D Y 7 5 S T O R Y A N D P H I L O S O P H Y Software is eating the world and what most of us see of it is the user interface. The user interface has become the key component of how the users experience the business behind it. Competition is lost or won due to user experience. Simplicity is king and the users get frustrated by anything ugly, slow or not working on the device they happen to use at the time. We at Vaadin fight for simplicity and invite everyone to join this fight. Together we want to build a user interface that puts a smile on the user’s face. Vaadin is the technology that empowers developers to build the best web-apps for business purposes. Our priority over everything else is developer productivity because we believe that by simplifying the developer experience and saving the developer’s time, they are best able to focus on building great user interfaces. Our brand is what we want everyone to think about us. When everyone - both us and the people around us - have a consistent understanding of what Vaadin is and what we stand for, it enables that image to spread and amplify. This book defines what we want that image to be. It defines what the Vaadin brand is. I hope that You are as excited and proud of living and breathing the Vaadin brand as I am. You are the one who is shaping what everyone thinks about Vaadin - using this brand as a tool and a guideline every day. Let’s fight for simplicity for both the users and the developers! Joonas Lehtinen Founder & CEO Vaadin I N T R O D U C T I O N
4. N O T T H E U S U A L K O T L I N 1 0 1
5. K O T L I N F O R P R O U S E R S
6. M I G R AT E A P P S T O K O T L I N
7. M I G R AT E A P P S T O K O T L I N Apps: • Big or enterprise Apps • Apps in production • Real world examples
8. 1. Kotlin migration 101 2.Hands on migration to Kotlin Agenda
9. K O T L I N M I G R AT I O N 1 0 1
10. Kotlin migration cheatsheet Kotlin 101 Koans ⌥⇧⌘K Improvise
11. Kotlin migration cheatsheet Kotlin 101 Koans ⌥⇧⌘K Improvise
12. Java int sum(int a, int b) { return a + b; }
13. Kotlin " fun sum(a: Int, b: Int): Int { return a + b }
14. Kotlin fun sum(a: Int, b: Int): Int = a + b
15. Kotlin fun sum(a: Int, b: Int) = a + b
16. Kotlin fun sum(a: Int, b: Int) = a + b fun sum(a: Int, b: Int): Int = a + b
17. N O T T H E U S U A L K O T L I N 1 0 1
18. Kotlin migration cheatsheet Kotlin 101 Koans ⌥⇧⌘K Improvise
19. Koans
20. Koans
21. Koans Demo
22. Kotlin migration cheatsheet Kotlin 101 Koans ⌥⇧⌘K Improvise
24. Kotlin migration cheatsheet Kotlin 101 Koans ⌥⇧⌘K Improvise
25. Kotlin migration cheatsheet Kotlin 101 Koans ⌥⇧⌘K Improvise
26. Kotlin migration cheatsheet Kotlin 101 Koans ⌥⇧⌘K Improvise
28. H A N D S O N M I G R AT I O N T O K O T L I N
29. Java vs Kotlin
30. Java vs Kotlin
31. I S I T W O R T H I T ?
33. M Y L I T T L E S T O R Y
34. 16 Feb 2017
35. May - June 2017
 
 Coincidence?
36. Google I/O
 
 (17 May 2017)
37. Artifact Size Kilobytes 0 2000 4000 6000 8000 Groovy (v2.4.15) Clojure (v1.9.0) Scala (v2.12.5) Kotlin (v1.2.31)
38. Artifact Size Kilobytes 0 700 1400 2100 2800 Guava (24.1-jre) Kotlin (v1.2.31)
39. Community 16,682 members 43,323 followers 9,844 questions 9,700 readers
40. GitHub Stars Stars (thousands) 0 5 10 15 20 25 Ceylon Groovy Clojure Scala Kotlin
41. • Object Oriented + Statically typed • Lambda + Properties • Null safety • Get rid of boilerplate • Functional programing • Seamless Java inter-op • Targets JS/Android/Native
43. https://medium.com/keepsafe-engineering/kotlin-vs-java-compilation-speed-e6c174b39b5d
44. Kotlin's hidden costs https://sites.google.com/a/athaydes.com/renato-athaydes/posts/kotlinshiddencosts-benchmarks
45. • Java - The Platform (JVM) • Java - The Language This thing called Java
46. • The Java Virtual Machine and its tooling ecosystem • Tested, trusted and supported on multiple platforms • Very versatile and successful • Held back by legacy baggage Java - The Platform
47. • Tightly coupled to Java, the platform • Good, old, well known, well tested • Fairly good but not excellent type system • Some not-so-great default behavior (e.g final vs non-final) Java - The Language
49. Kotlin fun sum(a: Int, b: Int) = a + b fun sum(a: Int, b: Int): Int = a + b
52. Clean Architecture? • Extensible & reusable modules. • Independence from framework / database / UI. • Testability.
53. Demo
54. Steps summary • Refactor the architecture. • Create a new Kotlin project. • Don’t modify your main project.
55. Steps summary • Start with the backend. • Start with less dependent classes (e.g. Data Models). • Seek alternative libraries.
56. W H AT A B O U T T H E F R O N T E N D ?
57. Vaadin on Kotlin
58. Vaadin on Kotlin www.vaadinonkotlin.eu
 100% Community effort
 Maintained by Martin Vysny
59. Final App https://github.com/mvysny/vaadin-on-kotlin
60. Browserless UI Testing https://github.com/mvysny/karibu-testing
64. Choosing the language primarily depends on the use you need it for. Scala is a good 7it for projects with a need for a mix of functional and OOP style programming languages. If you just wanted Java to be less frustrating — but still be Java — then there is nothing better than Kotlin out there. https://dzone.com/articles/kotlin-vs-scala-vs-java
65. 5 S T O R Y A N D P H I L O S O P H Y Software is eating the world and what most of us see of it is the user interface. The user interface has become the key component of how the users experience the business behind it. Competition is lost or won due to user experience. Simplicity is king and the users get frustrated by anything ugly, slow or not working on the device they happen to use at the time. We at Vaadin fight for simplicity and invite everyone to join this fight. Together we want to build a user interface that puts a smile on the user’s face. Vaadin is the technology that empowers developers to build the best web-apps for business purposes. Our priority over everything else is developer productivity because we believe that by simplifying the developer experience and saving the developer’s time, they are best able to focus on building great user interfaces. Our brand is what we want everyone to think about us. When everyone - both us and the people around us - have a consistent understanding of what Vaadin is and what we stand for, it enables that image to spread and amplify. This book defines what we want that image to be. It defines what the Vaadin brand is. I hope that You are as excited and proud of living and breathing the Vaadin brand as I am. You are the one who is shaping what everyone thinks about Vaadin - using this brand as a tool and a guideline every day. Let’s fight for simplicity for both the users and the developers! Joonas Lehtinen Founder & CEO Vaadin I N T R O D U C T I O N ?? ?
66. Kudos to.. • Martin Vysny @MartinVysny • Sayo Oladeji @oluwasayo_
67. T H A N K Y O U ! @ A M A H D Y 7 5 S T O R Y A N D P H I L O S O P H Y Software is eating the world and what most of us see of it is the user interface. The user interface has become the key component of how the users experience the business behind it. Competition is lost or won due to user experience. Simplicity is king and the users get frustrated by anything ugly, slow or not working on the device they happen to use at the time. We at Vaadin fight for simplicity and invite everyone to join this fight. Together we want to build a user interface that puts a smile on the user’s face. Vaadin is the technology that empowers developers to build the best web-apps for business purposes. Our priority over everything else is developer productivity because we believe that by simplifying the developer experience and saving the developer’s time, they are best able to focus on building great user interfaces. Our brand is what we want everyone to think about us. When everyone - both us and the people around us - have a consistent understanding of what Vaadin is and what we stand for, it enables that image to spread and amplify. This book defines what we want that image to be. It defines what the Vaadin brand is. I hope that You are as excited and proud of living and breathing the Vaadin brand as I am. You are the one who is shaping what everyone thinks about Vaadin - using this brand as a tool and a guideline every day. Let’s fight for simplicity for both the users and the developers! Joonas Lehtinen Founder & CEO Vaadin I N T R O D U C T I O N