CDI 2.0 (JSR 365) - Speaker Deck

Slide 1

Slide 1 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | CDI 2.0 (JSR 365) Contexts and Dependency Injection for Java 2.0 Akihiro Nishikawa Cloud Technology Business Unit Oracle Corporation Japan 17, May, 2017 Java Day Tokyo 2017 #JavaDayTokyo

Slide 2

Slide 2 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Safe Harbor Statement The following is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle. 2

Slide 3

Slide 3 text

Slide 4

Slide 4 text

Slide 5

Slide 5 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | What’s CDI? • Lifecycle for stateful objects bound to lifecycle contexts • Type-safe dependency injection mechanism • Event notification • Integration with the Unified Expression Language (EL) • ... 5 Major theme of CDI is “loose coupling”

Slide 6

Slide 6 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | CDI 2.0 (JSR-365) • Major evolution of the CDI 1.2 (JSR 346) specification • Spec Lead – Antoine Sabot-Durand (Red Hat Inc.) (@antoine_sd) • Reference Implementation – Weld : http://download.jboss.org/weld/3.0.0.Final/ 6 http://www.cdi-spec.org (@cdispec)

Slide 7

Slide 7 text

Slide 8

Slide 8 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 8 CDI Timeline December 2009 CDI 1.0 (Java EE 6) June 2013 CDI 1.1 (Java EE 7) April 2014 CDI 1.2 (1.1 Maintenance Release) September 2014 CDI 2.0 starts… May 2017 CDI 2.0

Slide 9

Slide 9 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | CDI 1.0 (JSR-299) • A well-defined lifecycle for stateful objects bound to lifecycle contexts – Where the set of contexts is extensible • A type-safe dependency injection mechanism without verbose configuration – Dependencies can be selected at development or deployment time • Type-safe decorators and interceptors • An event notification model • An SPI allowing portable extensions to integrate cleanly with the container 9 Contexts and Dependency Injection for the Java EE platform 1.0

Slide 10

Slide 10 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | CDI 1.1/1.2 (JSR-346) • Add automatic enablement of CDI in Java EE (beans.xml is not required) • Add introspection with event, bean, decorator and interceptor meta data • Ease access to bean manager from outside CDI with CDI class • Add global enablement of interceptors using the @Priority annotation • Add unmanaged allowing easy access to non-contexutal instances • Spec clarification of CDI Lifecycle and Events 10 Contexts and Dependency Injection for the Java EE platform 1.1/1.2

Slide 11

Slide 11 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | CDI 1.1/1.2 (JSR-346) • Reworking Bean defining annotation to avoid conflict with other JSR 330 frameworks • Clarification on conversation resolution • OSGi official support in the API 11 Contexts and Dependency Injection for the Java EE platform 1.1/1.2

Slide 12

Slide 12 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 12 CDI is associated with the following specs DI (Dependency Injection) EJB (Enterprise JavaBeans) Bean Validation Interceptors Managed Beans Common Annotation CDI JSF (JavaServer Faces)

Slide 13

Slide 13 text

Slide 14

Slide 14 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Major Changes • Spec was split into 3 parts • Java SE Support – Using CDI outside Java EE • Alignment on Java 8 features (streams, lambdas, repeating qualifiers) • Event enhancement • Configurators for major SPI elements • Possibility to configure or veto observer methods • Add built-in annotation literals • Make possible to apply interceptor on producers 14

Slide 15

Slide 15 text

Slide 16

Slide 16 text

Slide 17

Slide 17 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Why the spec was split? • To align on many other Java EE spec which support Java SE bootstrapping – JAX-RS, JPA... • To boost CDI adoption for Spec and Frameworks – Java SE has been already supported by Weld, Apache OpenWebBeans, Apache DeltaSpike and so on, but API is different from each implementation. – Programming model should be defined to avoid user confusion. • To provide a mean of building new stacks out of Java EE (MicroProfile) 17

Slide 18

Slide 18 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Name was changed... • JSR 346 Contexts and Dependency Injection for Java EE • JSR 365 Contexts and Dependency Injection for Java 18

Slide 19

Slide 19 text

Slide 20

Slide 20 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | CDI 1.x • Not specified • Depending upon each implementation – Weld – Apache DeltaSpike – ... CDI 2.0 • Standard API is specified • Must explicitly boot CDI container 20 API to boot CDI in Java SE

Slide 21

Slide 21 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | API to boot CDI in Java SE import javax.enterprise.inject.se.SeContainer; import javax.enterprise.inject.se.SeContainerInitializer; public class Sample { public static void main(String... args) { try (SeContainer container = SeContainerInitializer .newInstance() .initialize()) { ... } } } 21

Slide 22

Slide 22 text

Slide 23

Slide 23 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | SeContainer interface • Handle for CDI Interface – The handle is used to access the BeanManager • AutoCloseable • Extends javax.enterprise.inject.Instance – Able to use SeContainer to look up Instance programatically – If no qualifier is passed to SeContainer#select(), the @Default qualifier is assumed. – If no required type is given, the required type is the same as the parent’s one. • Able to use CDI#current() 23 javax.enterprise.inject.se.SeContainer

Slide 24

Slide 24 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Controlling the classpath try (SeContainer container = SeContainerInitializer.newInstance() .addPackages(Pojo.class) .disableDiscovery() .initialize()) { ... } 24 When adding Beans explicitly, bean discovery should be disabled

Slide 25

Slide 25 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Configurable try (SeContainer container = SeContainerInitializer.newInstance() .addExtensions() .enableDecorators() .selectAlternativeStereotypes() .selectAlternatives() .addProperty() .initialize()) { ... } 25 Able to add Alternatives, Stereotypes, Decorators, and Extensions

Slide 26

Slide 26 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Request Context Management • In Java SE, most of built-in contexts is unavailable… –Request context –Session context –Conversation context –... 26 Why is this feature required?

Slide 27

Slide 27 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Request Context Management • Start and stop request context programmatically through built-in bean • Provide built-in Interceptor to handle it automatically • This feature is also available for Java EE. 27 How to manage request contexts

Slide 28

Slide 28 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Request Context Management @ApplicationScoped public class MyBean { @Inject RequestContextController requestContextController; public void doRequest(String body) { boolean started = requestContextController.activate(); ... if( started ) { requestContextController.deactivate(); } } } 28 1) Built-in Beans to activate/deactivate Request Context

Slide 29

Slide 29 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Request Context Management @ApplicationScoped public class MyBean { @ActivateRequestContext public void doRequest(String body) { // Request context is activated during this invocation ... } } Priority Interceptor.Priority.PLATFORM_BEFORE + 100 (100) 29 2) Built-in Interceptor for automatically processing

Slide 30

Slide 30 text

Slide 31

Slide 31 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Java 8 Alignment • Use Java 8 feature and functionalities heavily – Functional Interface – Stream • For example, Instance directly supports Stream API – Previously, unable to use Stream API along with Instance • Custom libraries using CDI 1.x might be built again to align with CDI 2.0 31

Slide 32

Slide 32 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Example @Inject @Any private Instance objects; public void onBean(@Observers AfterBeanDiscovery abd) { abd.addBean().produceWith(instance -> new Object()) .destroyWith((o, cc) -> {}); objects.stream().filter(Objects::nonNull) .forEach(o->o.notify()); ... 32 Builder-based Bean Configuration, Lambda expression, and Stream API

Slide 33

Slide 33 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Repeating Qualifier • Able to qualify classes and methods using the same annotation – Supported by language level • In case of get all annotations… 33 javax.enterprise.inject.spi.Annotated.getAnnotations()

Slide 34

Slide 34 text

Slide 35

Slide 35 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Event Ordering • Event ordering using @Priority – The lowest value is first – Observers with no explicit priority have a middle range priority for allowing observer to be called last – Observer with the same priority are called in an undefined order • Only applicable to synchronous events – @Priority does not work for ordering asynchronous events 35

Slide 36

Slide 36 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Event Ordering import javax.enterprise.inject.spi.ObserverMethod; import javax.interceptor.Interceptor; ... // ObserverMethod.DEFAULT_PRIORITY // = Interceptor.Priority.APPLICATION + 500 System.out.println(ObserverMethod.DEFAULT_PRIORITY); // 2500 System.out.println(Interceptor.Priority.APPLICATION); // 2000 36 Default Priority

Slide 37

Slide 37 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Event Ordering public void observer1( @Observes @Priority(1) Payload p) { ... } public void observer2( @Observes @Priority(2) Payload p) { ... } 37 Example 1

Slide 38

Slide 38 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Event Ordering public class MyExtension implements Extension { public void firstProcessAnnotatedType( @Observes @Priority(1) ProcessAnnotatedType> pat) { ... } public void secondProcessAnnotatedType( @Observes @Priority(2) ProcessAnnotatedType> pat) { ... } } 38 Example 2 – along with portable extensions

Slide 39

Slide 39 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Events in CDI 1.x • Sync/Async is not specified, but implementation uses Synchronous model – Observers are called in the firing thread (i.e. synchronous event) without particular order specified • Immutable status of the payload is not specified – Payload is mutated in some implements and framework • Observers may inject beans • Observers are aware of Transactional and security contexts 39

Slide 40

Slide 40 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Synchronous Events @Inject Event event; public void syncCaller() { // Fire an event synchronously event.fire(new Payload()); } public void syncCallee(@Observes Payload p) { // Do something } 40 Firing and Observing events

Slide 41

Slide 41 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Asynchronous Events • Unable to mutate payload • Unable to access CDI contexts state at the firing point • Not transactional Event#fireAsync() @ObservesAsync 41 CDI 2.0

Slide 42

Slide 42 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Asynchronous Events @Inject Event event; public void asyncCaller() { // Fire an event asynchronously event.fireAsync(new Payload()); } public void syncCallee(@ObservesAsync Payload p) { // Do something } 42 Firing and observing events

Slide 43

Slide 43 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Asynchronous Events @Inject Event event; public void someMethod() { event.fireAsync( new PanelUpdater(green), executor); ... } 43 Example 1 – Executor

Slide 44

Slide 44 text

Slide 45

Slide 45 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Asynchronous Events • Exception raised in one async observer does not stop execution as in sync observer. – One of the reasons why firing async event does not trigger sync observers. • Event.fireAsync returns CompletionStage – Exception in fireAsync returned CompletionStage is CompletionException, which holds all the exceptions in the suppressed exception set. • Allowing integration of async events in standard Java 8 async pipeline. 45 Exception handling

Slide 46

Slide 46 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Asynchronous Events @Inject Event event; public void someMethod() { ... CompleteionStage stage = event.fireAsync( new PanelUpdater(green), SwingUtilities::invokeLater ); ... } 46 Example 3 – Exception handing

Slide 47

Slide 47 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Asynchronous Events • stage.whenComplete() – To handle result or exception • stage.handle() – Same as above but allows transformation of stage. • stage.exceptionally() – Used in the only case for treating exception 47 Exception handling with standard Java 8 Asynchronous API

Slide 48

Slide 48 text

Slide 49

Slide 49 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Are you planning migration to asynchronous events? • Simple replacement might raise problems! • Recommendation – In case of using sync events as of now, you should keep as it is. – Some limitation should be recognized. – Going sync/async should be a decision taken from firing side. – Being sync should be possible from observing side. 49

Slide 50

Slide 50 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Threading and Events in Java SE • Async events – Able to use Custom Executor • Sync events – Always within the same thread – When observers handle synchronous event in Java SE, request scope activation might be required. 50 @Inject Event event; @ActivateRequestContext public void syncSender() { event.fire(event); ... } public void syncReceiver( @Observes Pojo event ) { ... }

Slide 51

Slide 51 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Previous • BeanManager#fireEvent() CDI 2.0 • BeanManager#getEvent() – Able to get Event object – Event is typed to Object and implicitly annotated with @Default qualifier • BeanManager#fireEvent() is deprecated since CDI 2.0. 51 Programmatic Events

Slide 52

Slide 52 text

Slide 53

Slide 53 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 53 Indeed AnnotationLiteral is helpful if there is no member in an annotation. Standard Annotation Instances Annotation instance = new AnnotationLiteral(){};

Slide 54

Slide 54 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 54 But we have to create a class when an annotation has members... Standard Annotation Instances public class NamedLiteral extends AnnotationLiteral implements Named{ private String value; public NamedLiteral(String value) { this.value = value; } @Override public String value() { return null; } }

Slide 55

Slide 55 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | • javax.enterprise.inject. – Any – Default – New – Specialized – Vetoed • javax.enterprise.util. – Nonbinding • javax.enterprise.inject. – Alternative – Typed • javax.enterprise.context. – Initialized – Destroyed – RequestScoped – SessioScoped – ApplicationScoped – Dependent – ConversationScoped 55 Built-in annotation literals

Slide 56

Slide 56 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Built-in annotation literals Default defaultLiteral = new Default.Literal(); // No members ApplicationScoped literal = ApplicationScoped.Literal.INSTANCE; // If annotation have members Initialized initializedForApplicationScoped = new Initialized.Literal(ApplicationScoped.class); Initialized initializedForRequestScoped = Initialized.Literal.of(RequestScoped.class); 56 Example

Slide 57

Slide 57 text

Slide 58

Slide 58 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Configurators for metadata • AnnotatedType • InjectionPoint • Bean • ObserverMethod 58 Even if adding info to an existing metadata, quite verbose work is required.

Slide 59

Slide 59 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 59 In CDI 1.2 Configurators for metadata I want to modify some legacy framework which contains @CacheContext annotations in order to adapt CDI. What should I do? If I were you, I would create some extension to replace @CacheContext annotation with @Inject in AnnotatedTypes... But Do I have to create huge codes to do so? Exactly...

Slide 60

Slide 60 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Configurators interfaces • AnnotatedType – AnnotatedTypeConfigurator • InjectionPoint – InjectionPointConfigurator • BeanAttributes – BeanAttributesConfigurator • Bean – BeanConfigurator • ObserverMethod – ObserverMethodConfigurator • Producer – ProducerConfigurator 60 Newly introduced in CDI 2.0

Slide 61

Slide 61 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 61 In CDI 2.0 Configurators for meta-data What do you do when you want to adapt CDI to some legacy framework? If I were you, I would create metadata with “configurators”, which are accessible through container lifecycle events and automatically built by the container at the end of observer invocation. Oh, it sounds nice…

Slide 62

Slide 62 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | CDI 2.0 public class AutoInjectExtension implements Extension { public void CreateIP( @Observes @WithAnnotations(CacheContext.class) ProcessAnnotatedType pat) { pat.configureAnnotatedType().filterFields( f -> f.isAnnotationPresent(CacheContext.class) ).forEach(f -> f.add(InjectLiteral.INSTANCE)); } } 62

Slide 63

Slide 63 text

Slide 64

Slide 64 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Application Lifecycle Events (fired only one time) • Startup – BeforeBeanDiscovery – AfterTypeDiscovery – AfterBeanDiscovery – AfterDeploymentValidation • Shutdown – BeforeShutdown Bean Discovery Events (might be fired multiple times) – ProcessAnnotatedType – ProcessInjectionPoint – ProcessInjectionTarget – ProcessBeanAttributes – ProcessBean – ProcessProducer – ProcessObserverMethod 64 Container lifecycle events

Slide 65

Slide 65 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Directing requests Type Discovery Search service providers Bean Discovery 65 Container Startup Application Lifecycle Events BeforeBeanDiscovery Detect deployment problems AfterTypeDiscovery AfterBeanDiscovery AfterDeploymentValidation

Slide 66

Slide 66 text

Slide 67

Slide 67 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Add new methods in ProcessObserverMethod public interface ProcessObserverMethod { ... // Replaces the ObserverMethod public void setObserverMethod(ObserverMethod observerMethod); // Returns a ObserverMethodConfigurator initialized with the ObserverMethod processed by this event public ObserverMethodConfigurator configureObserverMethod(); // forces the container to ignore the ObserverMethod public void veto(); } 67 javax.enterprise.inject.spi.ProcessSyntheticObserverMethod

Slide 68

Slide 68 text

Slide 69

Slide 69 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | 69 Able to apply @Transactional to a producer method Interceptor is not bound to a produced Bean in CDI 1.x @Produces @Transactional public MyService produceService() { ... }

Slide 70

Slide 70 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | IntereptionFactory Interface public interface InterceptionFactory { InterceptionProxyFactory ignoreFinalMethods(); AnnotatedTypeConfigurator configure(); T createInterceptedInstance(T InstanceToWrap); } 70 javax.enterprise.inject.spi.InterceptionFactory

Slide 71

Slide 71 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Add @transactional on one produced bean method @Produces @RequestScoped public MyClass createJpaEmAssumed(InterceptionFactory f) { AnnotatedTypeConfigurator atc = f.configure(); atc.filterMethods(m -> m.getJavaMember() .getName() .equals("doSomething")) .findFirst() .ifPresent(m -> m.add( new AnnotationLiteral(){ })); return f.createInterceptedInstance(new MyClass()); } 71 CDI 2.0

Slide 72

Slide 72 text

Slide 73

Slide 73 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Programmatic lookup – Instance Enhancement Instance obj; ... if( !obj.isAmbiguous() && !obj.isUnsatisfied() ) { ... } 73 Previous isUnsatisfied() Returns true if there is no bean found, or false otherwise. isAmbiguous() Returns true if there is more than one bean found, or false otherwise.

Slide 74

Slide 74 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Programmatic lookup – Instance Enhancement Instance obj; ... if(obj.isResolvable()) { ... } 74 CDI 2.0 isResolvable() Returns true if there is exactly one bean found, or false otherwise.

Slide 75

Slide 75 text

Slide 76

Slide 76 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Key takeaway • Able to use CDI 2.0 on Java EE as well as Java SE. • Enhancements and new features help increase developer productivity. • Weld 3.0, reference Implementation of CDI, will be integrated with GlassFish 5 soon! 76

Slide 77

Slide 77 text

Slide 78

Slide 78 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Deprecated methods When? Method Alternatives CDI 2.0 BeanManager#fireEvent() BeanManager#getEvent() CDI 1.1 BeanManager#createInjectionTarget() BeanManager#getInjectionTargetFactory() CDI 1.1 javax.enterprise.inject .spi.Bean#isNullable() No alternatives CDI 1.1 AnnotatedMember#isStatic() Check with AnnotatedMember#getJavaMember().getModi fiers() CDI 1.1 BeforeBeanDiscovery#addAnnotatedType( AnnotatedType> type) eforeBeanDiscovery#addAnnotatedType( AnnotatedType> type, String id) 78

Slide 79

Slide 79 text

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. | Safe Harbor Statement The preceding is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle. 79