1. RX JAVA
MATEUSZ BUKOWICZ

2. REACTIVEX

3. REACTIVE SUPPORT IN DIFFERENT LANGUAGES
REACTIVE EXTENSIONS
▸ Rx.Net
▸ RxJava
▸ RxJS
▸ RxScala
▸ RxClojure
▸ RxCpp
▸ Rx.rb
▸ RxPY
▸ RxGroovy
▸ RxJRuby
▸ RxKotlin
▸ RxSwift

4. HOW IT BEGAN
RX.NET
▸ Rx.NET released in 2009
▸ Shipped with .NET 4.0 (2010)

5. AN API FOR ASYNCHRONOUS
PROGRAMMING WITH
OBSERVABLE STREAMS.
reactivex.io
DEFINITION

6. OBSERVER AGAIN
OBSERVER PATTERN
https://en.wikipedia.org/wiki/Observer_pattern
Observable

7. WHAT IS REACTIVE?
REACTIVE MANIFESTO
▸ responsive
▸ resilient
▸ elastic
▸ message-driven

8. REACTIVE CAN BE REPULSIVE
REACTIVE MANIFESTO CONTROVERSY

9. REACTIVE AS A LIFESTYLE
REACTIVE PROGRAMMING

10. OLD WAY OF DOING THINGS
PROCEDURAL WAY

11. FROM PROCEDURAL TO FUNCTIONAL
FUNCTIONAL WAY

12. FROM FUNCTIONAL TO REACTIVE
REACTIVE WAY

13. HOW TO OBSERVE?
ITERABLE VS OBSERVABLE
http://reactivex.io/intro.html

14. OBSERVER OBSERVES
OBSERVER USAGE

15. OPERATORS - FILTER
FILTER
http://rxmarbles.com/#filter

16. OPERATORS - TAKE
TAKE
http://rxmarbles.com/#take

17. OPERATORS - ZIP
ZIP
http://rxmarbles.com/#zip

18. WHICH OPERATORS SHOULD I USE?
OPERATORS DECISION TREE
http://reactivex.io/documentation/operators.html#tree

19. NETFLIX OLD WAY - PROBLEM
http://techblog.netflix.com/2012/07/embracing-differences-inside-netflix.html

20. NETFLIX OLD WAY - PROBLEM
http://techblog.netflix.com/2012/07/embracing-differences-inside-netflix.html

21. NETFLIX OLD WAY - PROBLEM
http://techblog.netflix.com/2013/01/optimizing-netflix-api.html

22. NETFLIX NEW WAY - SOLUTION
http://techblog.netflix.com/2013/01/optimizing-netflix-api.html

23. THINK ABOUT THE FUTURE
single item multiple items
sync T getData() Iterable<T> getData()
async Future<T> getData() ?
List<Future<T>> getData()

24. A NEW GUY COMES IN
RX.NET IS SO COOL

25. OBSERVABLE TO THE RESCUE
single item multiple items
sync T getData() Iterable<T> getData()
async Future<T> getData()
Observable<T>
getData()

26. NETFLIX NEW WAY - SOLUTION
http://techblog.netflix.com/2012/07/embracing-differences-inside-netflix.html

27. NETFLIX NEW WAY - SOLUTION
http://techblog.netflix.com/2012/07/embracing-differences-inside-netflix.html

28. http://techblog.netflix.com/2013/02/rxjava-netflix-api.html

29. PARALLEL WORK
CONCURRENCY
▸ most operators - synchronous by default
▸ some operators - implicit concurrency
▸ programmatic concurrency: observeOn/subscribeOn

30. http://reactivex.io/documentation/scheduler.html
can be anywhere

31. RX.JAVA SCHEDULERS
SCHEDULERS
http://reactivex.io/documentation/scheduler.html

32. SCHEDULERS IN ACTION

33. REACTIVE ANDROID
RX ANDROID

34. ERROR HANDLING
ON ERROR RESUME NEXT
http://reactivex.io/documentation/operators/catch.html

35. OH, MY BACK!
BACK PRESSURE

36. BACKPRESSURE-RELATED OPERATORS
BUFFER OPERATOR
https://github.com/ReactiveX/RxJava/wiki/Backpressure

37. BACK PRESSURE
ON BACKPRESSURE BUFFER
https://github.com/ReactiveX/RxJava/wiki/Backpressure

38. MORE RESILIENT RX.JAVA
HYSTRIX + RX.JAVA
https://github.com/Netflix/Hystrix/wiki/How-To-Use#Reactive-Execution

39. CIRCUIT BREAKER
CLOSED
OPENHALF-OPEN
failure threshold
reached
timeout timer
expired
operation failed
success count
threshold reached
always
return
failure
increment failure
counter on failure
increment
success
counter on
success
start

40. REACTIVE NETTY
RX NETTY
https://github.com/Netflix-Skunkworks/WSPerfLab/blob/master/test-results/RxNetty_vs_Tomcat_April2015.pdf
CPU saturated
clients
req/s avg lat [ms]

41. RX NETTY VS TOMCAT
WHY RX NETTY IS BETTER?
▸ lower CPU consumption
▸ lower object allocation rate/less GC
▸ event loop architecture vs thread pool architecture
▸ no thread pool locks
▸ less thread migrations
▸ more CPU Instructions Per Cycle (IPC)
https://github.com/Netflix-Skunkworks/WSPerfLab/blob/master/test-results/RxNetty_vs_Tomcat_April2015.pdf

42. REACTIVE STREAMS - INITIATIVE
http://www.reactive-streams.org

43. REACTIVE STREAMS - SCOPE
http://www.reactive-streams.org

44. FUTURE IS REACTIVE
JAVA 9 FLOW API
▸ JDK 9.0
▸ RxJava 2.x -> Reactive Streams implementation
▸ JPA -> Hibernate
▸ Reactive Streams -> RxJava 2.x

45. THE END