JAX-RS and CDI Bike the (ReacIve) Bridge CON2549

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2 JAX-RS and CDI Bike the (ReacIve) Bridge CON2549 David Delabassée - Oracle José Paumard - Consultant October,

3 @delabassee 3

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5 Safe Harbor Statement The following is intended to outline our general product direcion. It is intended for informaion purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or funcionality, and should not be relied upon in making purchasing decisions. The development, release, and Iming of any features or funcionality described for Oracle s products remains at the sole discreion of Oracle. 5

6 Copyright 2017, Oracle and/or its affiliates. All rights reserved. 6

7 reacive adjecive re ac Ive \ rē-ˈak-iv \ 1 :of, relaing to, or marked by reacion or reactance 2 a :readily responsive to a simulus h`ps:// 7

8 JAX-RS 8

9 JAX-RS 2.1 Java API for RESTful Web Services JSR 370 Java EE 8 Async New ReacIve Client API New method for pausing resquest processing, etc. Server-Sent Event support JSON-P & JSON-B support 9

10 JAX-RS Client API // JAX-RS 2.0 Client client = ClientBuilder.newClient(); WebTarget target = client.target(" "Paris"); Forecast forecast = target.request().get(forecast.class); // client.close(); 10

11 JAX-RS Client API javax.ws.rs.client.client interface Fluent API Client Builder è Client è Web Target è Request building è Response List<Forecast> forecast = ClientBuilder.newClient().target(" GenericType<List<Forecast>>() {}); 11

12 JAX-RS Client API JAX-RS 2.0 Invokers Synchronous invoker String city = client.target(" "Paris").request().get(String.class); Asynchronous invoker Future<String> fcity = client.target(" "Paris").request().async().get(String.class); 12

13 JAX-RS Client API Asynchronous invocajon Future<String> fcity = client.target(" "Paris").request().async().get(String.class); String city = fcity.get(); 13

14 JAX-RS Client API Asynchronous invocajon Future<String> fcity = client.target(" "Paris").request().async().get(String.class); try { String city = fcity.get(5, TimeUnit.SECONDS); } catch(timeoutexception timeout) { } // 14

15 JAX-RS Client API Asynchronous invocajon // Set ClientProperties.CONNECT_TIMEOUT & READ_TIMEOUT Future<String> fcity = client.target(" "Paris").request().async().get(String.class); while (!fcity.isdone() ) { } // response hasn't been received yet String city = fcity.get(); 15

16 JAX-RS Client API Asynchronous invocajon InvocaIonCallback Interface javax.ws.rs.client.invocationcallback<response> Container will receive async processing events from an invocaion completed(response response) failed(throwable throwable) 16

17 JAX-RS Client API InvocaJonCallback WebTarget myresource = client.target(" Future<Customer> future = myresource.request(mediatype.text_plain).async().get(new InvocationCallback<Customer>() { public void completed (Customer customer) { // do something with the customer public void failed (Throwable throwable) { // Oops! } 17

18 The Travel Service 18

19 The Travel Service Synchronous Customer details: 150 ms Recommended desinaions: 250 ms Price calculaion for a customer and desinaion: 170 ms (each) Weather forecast for a desinaion: 330 ms (each) ms 19

20 The Travel Service Asynchronous 730 ms 20

21 The Travel Service 21

22 The Travel Service destination.path("recommended").request().header("rx-user", "Async").async().get(new InvocationCallback<List<Destination>>() public void completed(final List<Destination> recommended) { final CountDownLatch innerlatch = new CountDownLatch(recommended.size()); final Map<String, Forecast> forecasts = Collections.synchronizedMap(new HashMap<>()); for (final Destination dest : recommended) { forecast.resolvetemplate("dest", dest.getdestination()).request().async().get(new InvocationCallback<Forecast>() public void completed(final Forecast forecast) { forecasts.put(dest.getdestination(), forecast); innerlatch.countdown(); } 22

23 The Travel Service // cont. public void failed(final Throwable throwable) { innerlatch.countdown(); } }); try { if (!innerlatch.await(10, TimeUnit.SECONDS)) { // timeout } } catch (final InterruptedException e) { // Ooops, interrupted! } } // Continue with processing public void failed(final Throwable throwable) { // Recommendation error } }); 23

24 JAX-RS Client API New JAX-RS ReacJve Invoker // JAX-RS 2.0 Response response = client.target(recommandationservice).request().get(); Future<Response> futureresponse = client.target(recommandationservice).request().async().get(); // JAX-RS 2.1 CompletionStage<Response> completionstageresp = client.target(recommandationservice).request().rx().get(); 24

25 CompleIonStage API A model for a Task That performs an acion and may return a value That can be triggered by another task That may trigger another task That can be executed in a different thread A CompleJonStage is an element of an asynchronous chain 25

26 CompleIonStage Pipeline CS 1 CS 21 CS 31 CS 41 CS 22 CS 32 26

27 The Travel Service CompletionStage<JsonObject> queryforecastcs = client.target("forecast").queryparam("format", "json").request().rx().get(jsonobject.class); Function<JsonObject, Forecast> unmarshallforecast = jsonobject -> JsonBuilder.create().fromJson(jsonObject.toString(), Forecast.class); Function<Destination, CompletionStage<Void>> populatewithforecast = destination -> queryforecastcs.thenapply(unmarshallforecast).thenaccept(forecast -> destination.setforecast(forecast)); Function<Destination, CompletionStage<Void>> populatewithquotation = destination -> queryquotationcs.thenapply(unmarshallquotation).thenaccept(quotation -> destination.setquotation(quotation)); 27

28 The Travel Service Function<Destination, CompletableFuture<Void>> populatedestination = destination -> CompletableFuture.allOf( populatewithforecast.apply(destination).tocompletablefuture(), populatewithquotation.apply(destination).tocompletablefuture() ).tocompletablefuture(); 28

29 The Travel Service Function<Destination, CompletableFuture<Void>> populatedestination = destination -> CompletableFuture.allOf( populatewithforecast.apply(destination).tocompletablefuture(), populatewithquotation.apply(destination).tocompletablefuture() ).tocompletablefuture(); Function<List<Destination>, CompletableFuture<?>[]> populatedestinations = destinations -> destinations.stream().map(populatedestination).toarray(completablefuture[]::new); 29

30 The Travel public void final AsyncResponse asyncresponse) { CompletionStage<List<Destination>> destinationcs = client.target("destination").queryparam("format", "json").request().rx().get(/* some JSONB code */); CompletionStage<List<Destination>> updateddestinationscs = destinationcs.thencompose(completablefuture.allof(populatedestinations)); } asyncresponse.resume(updateddestinationscs.tocompletablefuture().get()); 30

31 The Travel public CompletionStage<Destination> populatedestination() { CompletionStage<List<Destination>> destinationcs = client.target("destination").queryparam("format", "json").request().rx().get(/* some JSONB code */); CompletionStage<List<Destination>> updateddestinationscs = destinationcs.thencompose(completablefuture.allof(populatedestinations)); } return updateddestinationscs; 31

32 ExcepIon Handling CS 1 CS 21 CS 31 CS 41 CS 22 CS 32 32

33 ExcepIon Handling excepjonaly() Returns a new CompleJonStage That completes when the CS completes Either with the same result (normal compleion) Or with the transformed excepion stage.exceptionaly( // Function exception -> dosomethingnottoostupidwith(exception)); 33

34 ExcepIon Handling handle() Returns a new CompleJonStage That completes when the CS completes Calls the BiFuncJon with a null as result or excepion stage.handle( // BiFunction (result, exception) -> dosomethingwith(result, exception)); 34

35 ExcepIon Handling whencomplete() Returns a new CompleJonStage With the same result or excepion as this stage That executes the given acion when this stage completes stage.whencomplete( // BiConsumer + async version (result, exception) -> dosomethingwith(result, exception)); 35

36 ExcepIon Handling CompletionStage<Void> quotation = client.target("quotation").request().rx().get(jsonobject.class).thenapply(unmarshallquotation).exceptionnaly(throwable -> null).thenaccept(destination::setquotation); 36

37 ExcepIon Handling CompletionStage<Void> quotation = client.target("quotation").request().rx().get(jsonobject.class).thenapply(unmarshallquotation).handle(((quotation, throwable) -> { if (throwable == null) { destination.setquotation(quotation); } else { // try to do something smart with the exception } } 37

38 JAX-RS ReacIve Extensions Supported on all HTTP Methods of the Client API DELETE GET HEAD OPTIONS POST PUT TRACE 38

39 JAX-RS ReacIve Extensions ImplementaIons MUST support an invoker for CompleJonStage ImplementaIons MAY support other reacive APIs Jersey CompleIonStageRxInvoker (Default) RxListenableFutureInvoker Guava RxObservableInvoker RxJava RxFlowableInvoker RxJava2 client.register(rxflowableinvokerprovider.class); client.target(...)....rx(rxflowableinvoker.class).get(); h`ps://github.com/jersey/jersey/tree/master/ext/rx 39

40 CDI 40

41 CDI 2.0 Context and Dependency InjecJon JSR 365 Java EE 8 Java SE focus Modular specificaion CDI Container bootstraping Obersevers Ordering Asynchronous Events 41

42 Asynchronous Events // Event<Payload> event; public void acriticalbusinessmethod() { } CompletionStage<Payload> cs = event.fireasync(new Payload()); // Consumer public void anoberser(@observesasync Payload event) { // do something with the payload } 42

43 Asynchronous Events // Event<Payload> event; public void acriticalbusinessmethod() { } CompletionStage<Payload> cs = event.fireasync(new Payload(), executor); 43

44 Asynchronous Events // Event<Payload> event; public void acriticalbusinessmethod() { } CompletionStage<Payload> cs = event.fireasync(new Payload(), SwingUtilities::invokeLater); 44

45 Wrap-up 45

46 Java EE 8 ModernizaIon & SimplificaIon JAX-RS 2.1 Servlet 4.0 JSON-B 1.0 (*) JSON-P 1.1 CDI 2.0 Bean ValidaJon 2.0 JSF 2.3 Security 1.0 (*) ReacIve Client API, Server-Sent Events, HTTP/2, Server Push, Java <-> JSON binding Updates to JSON standards, JSON Collectors, Async Event, Observers ordering, SE support, Embrace Java SE 8, new constraints, Improved CDI, WebSocket, SE 8 integraion, Portable IdenIty Store, AuthenIcaIon & Security Context 46

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