RXJAVA 2.0 & MORE AT VERT.X / Julien Viet @julienviet 

ABOUT ME Open source developer for 15 years @vertx_project lead So ware engineer at Red Hat https://github.com/vietj @julienviet 

HTTP://VERTX.IO Vert.x is a tool-kit for building reactive and polyglot applications for the JVM 

TOOL-KIT 

< d e p e n d e n c y > < g r o u p i d > i o . v e r t x < / g r o u p i d > < a r t i f a c t i d > v e r t x - c o r e < / a r t i f a c t i d > < v e r s i o n > 3 . 3 . 3 < / v e r s i o n > < / d e p e n d e n c y > 

d e p e n d e n c i e s { c o m p i l e " i o . v e r t x : v e r t x - c o r e : 3 . 3 . 3 " } 

> b r e w i n s t a l l v e r t . x . . . > v e r t x r u n 

> s d k i n s t a l l v e r t x . . . > v e r t x r u n 

POLYGLOT Java 8 JavaScript Ceylon Groovy Ruby Scala (3.4) 

JAVA 8 p u b l i c c l a s s S e r v e r e x t e n d s A b s t r a c t V e r t i c l e { p u b l i c v o i d s t a r t ( ) { v e r t x . c r e a t e H t t p S e r v e r ( ) . r e q u e s t H a n d l e r ( r e q u e s t - > r e q u e s t . r e s p o n s e ( ) . p u t H e a d e r ( " c o n t e n t - t y p e " , " t e x t / p l a i n " ) . e n d ( " H e l l o f r o m V e r t . x " ) ) . l i s t e n ( 8 0 8 0 , " l o c a l h o s t " ) ; } } 

SCALA c l a s s S e r v e r e x t e n d s S c a l a V e r t i c l e { o v e r r i d e d e f s t a r t ( ) : U n i t = { v e r t x . c r e a t e H t t p S e r v e r ( ) . r e q u e s t H a n d l e r ( _ . r e s p o n s e ( ) . p u t H e a d e r ( " c o n t e n t - t y p e " , " t e x t / p l a i n " ) . e n d ( " H e l l o f r o m V e r t . x ! " ) ) . l i s t e n ( 8 0 8 0 ) } } 

CEYLON s h a r e d c l a s s S e r v e r ( ) e x t e n d s V e r t i c l e ( ) { s t a r t ( ) = > v e r t x . c r e a t e H t t p S e r v e r ( ) . r e q u e s t H a n d l e r ( ( r e q ) = > r e q . r e s p o n s e ( ) . p u t H e a d e r ( " c o n t e n t - t y p e " , " t e x t / p l a i n " ) . e n d ( " H e l l o f r o m V e r t . x ! " ) ) . l i s t e n ( 8 0 8 0 ) ; } 

JAVASCRIPT v e r t x . c r e a t e H t t p S e r v e r ( ) . r e q u e s t H a n d l e r ( f u n c t i o n ( r e q ) { r e q . r e s p o n s e ( ) . p u t H e a d e r ( " c o n t e n t - t y p e " , " t e x t / p l a i n " ) . e n d ( " H e l l o f r o m V e r t . x ! " ) ; } ) . l i s t e n ( 8 0 8 0 ) ; 

GROOVY v e r t x . c r e a t e H t t p S e r v e r ( ) . r e q u e s t H a n d l e r ( { r e q - > r e q . r e s p o n s e ( ) . p u t H e a d e r ( " c o n t e n t - t y p e " , " t e x t / p l a i n " ) . e n d ( " H e l l o f r o m V e r t . x ! " ) } ) . l i s t e n ( 8 0 8 0 ) 

RUBY $ v e r t x . c r e a t e _ h t t p _ s e r v e r ( ) . r e q u e s t _ h a n d l e r ( ) { | r e q | r e q . r e s p o n s e ( ) . p u t _ h e a d e r ( " c o n t e n t - t y p e " , " t e x t / p l a i n " ) . e n d ( " H e l l o f r o m V e r t . x ! " ) } . l i s t e n ( 8 0 8 0 ) 

REACTIVE Responsive Resilient Message Driven Elastic 

FEATURES Event driven Polyglot Event bus Lightweight / embeddable Clustering / HA 

RXJAVA Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM. Composable Flexible 

VERT.X AND RXJAVA Vert.x RxJava API Vert.x async and reactive constructs as Observable 

ASYNC COORDINATION v e r t x . c r e a t e H t t p S e r v e r ( ) . l i s t e n ( 8 0 8 0 , r e s u l t 1 - > { i f ( r e s u l t 1 . s u c c e e d e d ( ) ) { H t t p S e r v e r s 2 = v e r t x . c r e a t e H t t p S e r v e r ( ) ; s 2 . l i s t e n ( 8 0 8 1 , r e s u l t 2 - > { i f ( r e s u l t 2 . s u c c e e d e d ( ) ) { S y s t e m . o u t . p r i n t l n ( " S u c c e e d e d " ) ; } e l s e { S y s t e m . o u t . p r i n t l n ( " F a i l e d " ) ; } } ) ; } e l s e { S y s t e m . o u t . p r i n t l n ( " F a i l e d " ) ; } } ) ; 

O b s e r v a b l e < H t t p S e r v e r > o b s 1 = v e r t x . c r e a t e H t t p S e r v e r ( ) . r e q u e s t H a n d l e r ( r e q - > h a n d l e R e q u e s t ( r e q ) ) . l i s t e n ( 8 0 8 0 ) ; O b s e r v a b l e < H t t p S e r v e r > o b s 2 = v e r t x . c r e a t e H t t p S e r v e r ( ) . r e q u e s t H a n d l e r ( r e q - > h a n d l e R e q u e s t ( r e q ) ) . l i s t e n ( 8 0 8 1 ) ; O b s e r v a b l e . c o n c a t ( o b s 1 , o b s 2 ) . s u b s c r i b e ( s e r v e r - > { S y s t e m . o u t . p r i n t l n ( " S e r v e r s t a r t e d " ) ; } , e r r - > { S y s t e m . o u t . p r i n t l n ( " S o m e t h i n g w e n t w r o n g " ) ; e r r . p r i n t S t a c k T r a c e ( ) ; } ) ; 

STREAM COMPOSITION E v e n t B u s e b = v e r t x . e v e n t B u s ( ) ; M e s s a g e C o n s u m e r < I n t e g e r > c o n s = e b . m e s s a g e C o n s u m e r ( " s e n s o r " ) ; L i s t < D o u b l e > s a m p l e s = n e w A r r a y L i s t < > ( ) ; c o n s . h a n d l e r ( m s g - > { d o u b l e h e a t = m s g . b o d y ( ) ; s a m p l e s . a d d ( h e a t ) ; } ) ; v e r t x . s e t P e r i o d i c ( 1 0 0 0 , i d - > { d o u b l e h e a t = s a m p l e s . s t r e a m ( ) . c o l l e c t ( C o l l e c t o r s . a v e r a g i n g D o u b l e ( d - > d ) ) ; S y s t e m . o u t . p r i n t l n ( " C u r r e n t h e a t : " + h e a t ) ; } ) ; 

E v e n t B u s e b = v e r t x . e v e n t B u s ( ) ; M e s s a g e C o n s u m e r < D o u b l e > c o n s = e b . m e s s a g e C o n s u m e r ( " s e n s o r " ) ; O b s e r v a b l e < M e s s a g e < D o u b l e > > o b s = c o n s . t o O b s e r v a b l e ( ) ; o b s . m a p ( m s g - > m s g . b o d y ( ) ) . . b u f f e r ( 1 , T i m e U n i t . S E C O N D S ) . . m a p ( b u f f e r - > b u f f e r . s t r e a m ( ) . c o l l e c t ( C o l l e c t o r s . a v e r a g i n g D o u b l e ( d - > d ) ) ) . . s u b s c r i b e ( h e a t - > S y s t e m . o u t . p r i n t l n ( " C u r r e n t h e a t : " + h e a t ) ) ; 

RXJAVA 2 Release 2.0 scheduled soon Evolution of RxJava 1 API Full rewrite Based on Reactive Streams Better performances 

JAVA PACKAGES AND MAVEN COORDINATES CHANGES rx.Observable -> io.reactivex.Observable io.reactivex.rxjava:rxjava -> io.reactivex.rxjava2:rxjava 

OBSERVABLE INTERFACE IS NOT BACK- PRESSURED ANYMORE 

RXJAVA 2 STREAM TYPES Observable: multiple results Flowable: 0..n back-pressured 

RXJAVA 2 PROMISE LIKE TYPES Single: 1 result Maybe: 0 or 1 Completable: 0 

NULL VALUES ARE NOT ALLOWED ANYMORE!!! 

Use Maybe or Completable 

c l a s s M y T y p e { p u b l i c s t a t i c f i n a l M y T y p e N U L L _ S E N T I N E L = n e w M y T y p e ( ) ; . . . } O b s e r v a b l e < M y T y p e > o b s e r v a b l e = g e t O b j e c t s ( ) ; o b s e r v a b l e . s u s c r i b e ( o b j - > { i f ( o b j = = N U L L _ S E N T I N E L ) { / / N u l l i n s t a n c e } e l s e { / / N o t n u l l } } ) ; 

O b s e r v a b l e < O p t i o n a l < M y T y p e > > o b s e r v a b l e = g e t O b j e c t s ( ) ; o b s e r v a b l e . s u b s c r i b e ( o p t - > { o p t . i f P r e s e n t ( o b j - > { / / N u l l i n s t a n c e } } ) ; 

MIGRATING FROM RXJAVA 1 Does not come for free Full list of API change available RxJava2Interop project provides RxJava1 / RxJava2 adapters 

VERT.X AND RXJAVA 2 Changed to disallow null values in streams Pick the right type according to the context: Completable, Maybe or Single 

VERT.X AND RXJAVA 2 Support RxJava 1 and RxJava 2 Looks promising