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Vaadin CDI

Contexts and Dependency Injection for Vaadin

This add-on permits the use of primary CDI (JSR-299) features such as dependency injection, CDI events, etc. It also defines a new CDI scope for UIs and automatically configures a servlet for CDI if no Vaadin servlets are defined.

Compatibility

Getting started

Startup

If you do not customize Vaadin Servlet in your web.xml, a CDI enabled Vaadin servlet is deployed automatically.

As UI class CdiUI is configured. If you need a custom UI class, you have to extend this class. It is not a CDI contextual instance but injects work.

Otherwise, you can customize CdiVaadinServlet just like VaadinServlet.

Component instantiation and CDI

Vaadin triggered instantiation happens in a CDI aware Vaadin Instantiator implementation. Components created by this API:

• @Route, RouteLayout, HasErrorParameter components
• component fields injected by @Id to polymer templates

By default, instantiator looks up the CDI bean by type ( component class )
and gets a contextual reference from BeanManager. All the CDI features are usable like observer, interceptor, decorator.

When type is not found as a CDI bean ( for example ambiguous, or does not have a no-arg public constructor ), instantiation falls back to the default Vaadin behavior. On success, dependency injection is performed. Injects work, but other CDI features not. It is not a contextual instance.

Vaadin Contexts

In addition to standard CDI contexts, the CDI add-on introduces some new contexts. Read more about the supported scopes in Vaadin Docs

Services

Some Vaadin service interfaces can be implemented as a CDI bean.

• I18NProvider
• Instantiator
• SystemMessagesProvider
• ErrorHandler

Beans have to be qualified by @VaadinServiceEnabled to be picked up automatically.

Example code is available in Vaadin Docs

Vaadin Events

Following events fired as a CDI event:

• ServiceInitEvent
• PollEvent
• BeforeEnterEvent
• BeforeLeaveEvent
• AfterNavigationEvent
• UIInitEvent
• SessionInitEvent
• SessionDestroyEvent
• ServiceDestroyEvent

See example code in Vaadin Docs

Links

• Author Homepage
• Issue Tracker
• Source Code
• Tutorial
• Java EE Compatibility Matrix

Compatibility