ReactiveX Basics

The main principles and concepts used in the ReactiveX world

Transcript

1. ReactiveX Basics Catalin Morosan
2. An API for asynchronous programming with observable streams
3. A combination of the best ideas from
4. A combination of the best ideas from • Observer pattern
5. A combination of the best ideas from • Observer pattern • Iterator pattern
6. A combination of the best ideas from • Observer pattern • Iterator pattern • functional programming
7. Cross-platform
8. Cross-platform • Java
9. Cross-platform • Java (Android)
10. Cross-platform • Java (Android) • Scala
11. Cross-platform • Java (Android) • Scala • C#
12. Cross-platform • Java (Android) • Scala • C# • C++
13. Cross-platform • Java (Android) • Scala • C# • C++ • JavaScript
14. Cross-platform • Java (Android) • Scala • C# • C++ • JavaScript • Python
15. Cross-platform • Java (Android) • Scala • C# • C++ • JavaScript • Python • ...
16. Everywhere and meant for everything
17. Everywhere and meant for everything • Frontend
18. Everywhere and meant for everything • Frontend ◦ UI events / API responses
19. Everywhere and meant for everything • Frontend ◦ UI events / API responses ◦ web / mobile / desktop
20. Everywhere and meant for everything • Frontend ◦ UI events / API responses ◦ web / mobile / desktop • Backend
21. Everywhere and meant for everything • Frontend ◦ UI events / API responses ◦ web / mobile / desktop • Backend ◦ concurrency
22. Benefits
23. Benefits • Functional
24. Benefits • Functional • Less is more
25. Benefits • Functional • Less is more • Async error handling
26. Benefits • Functional • Less is more • Async error handling • Concurrency made easy
27. Concepts
28. Concepts • Observable
29. Concepts • Observable • Observer / Subscriber
30. Concepts • Observable • Observer / Subscriber • Scheduler
31. Concepts • Observable • Observer / Subscriber • Scheduler • Operator
32. Observable
33. Observable
34. Observer / Subscriber
35. Observer / Subscriber • connects to Observable to receive events
36. Observer / Subscriber • connects to Observable to receive events • onNext
37. Observer / Subscriber • connects to Observable to receive events • onNext • onError
38. Observer / Subscriber • connects to Observable to receive events • onNext • onError • onCompleted
39. Cold vs Hot Observables
40. Cold vs Hot Observables • cold - waits until subscriber subscribes to it before it begins emitting items
41. Cold vs Hot Observables • cold - waits until subscriber subscribes to it before it begins emitting items • hot - may begin emitting items as soon as it is created
42. Scheduler
43. Scheduler • subscribeOn - thread the Observable runs on
44. Scheduler • subscribeOn - thread the Observable runs on • observeOn - thread the Observable uses to send notifications to the subscribers
45. Scheduler • subscribeOn - thread the Observable runs on • observeOn - thread the Observable uses to send notifications to the subscribers • by default Observable runs and sends notifications on the current thread
46. Operators
47. Operators • most operate on Observable and return an Observable
48. Operators • most operate on Observable and return an Observable • you can apply operators one after the other, in a chain
49. Operators • most operate on Observable and return an Observable • you can apply operators one after the other, in a chain • extreme power in transforming one stream of elements into a completely different stream
50. Operators • most operate on Observable and return an Observable • you can apply operators one after the other, in a chain • extreme power in transforming one stream of elements into a completely different stream • large number of operators to choose from
51. Creating Observables
52. Operator : create
53. Operator : just
54. Operator : from
55. Filtering Observables
56. Operator : distinct
57. Operator : filter
58. Operator : last
59. Operator : take
60. Transforming Observables
61. Operator : map
62. Operator : debounce
63. Operator : flatMap
64. Combining Observables
65. Operator : merge
66. Operator : combineLatest
67. Operator : zip
68. Subject
69. Subject
70. Subject • acts as an Observer
71. Subject • acts as an Observer ◦ it can subscribe to one or more Observables
72. Subject • acts as an Observer ◦ it can subscribe to one or more Observables • acts as an Observable
73. Subject • acts as an Observer ◦ it can subscribe to one or more Observables • acts as an Observable ◦ it can reemit the items it observes
74. Subject • acts as an Observer ◦ it can subscribe to one or more Observables • acts as an Observable ◦ it can reemit the items it observes ◦ it can also emit new items
75. Subject • acts as an Observer ◦ it can subscribe to one or more Observables • acts as an Observable ◦ it can reemit the items it observes ◦ it can also emit new items • 4 types of Subjects designed for specific use cases
76. PublishSubject
77. BehaviorSubject
78. ReplaySubject
79. AsyncSubject
80. “ReactiveX is more than an API, it’s an idea and a breakthrough in programming.” reactivex.io
81. Thanks google.com/+CatalinMorosan