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[[framework-weld]]
=== Weld

http://seamframework.org/Weld[Weld] can be used to add support for CDI (Contexts and Dependency Injection) to Servlets, Listeners and Filters.
It is easily configured with Jetty 9.

[[weld-setup-distro]]
==== Weld Setup

The easiest way to configure weld is within the jetty distribution itself:

1.  Enable the startup link:#startup-modules[module] called "cdi".
2.  Ensure your `WEB-INF/web.xml` contains the following:
+
[source, xml, subs="{sub-order}"]
----
  <listener>
    <listener-class>org.jboss.weld.environment.servlet.Listener</listener-class>
  </listener>

  <resource-env-ref>
    <description>Object factory for the CDI Bean Manager</description>
    <resource-env-ref-name>BeanManager</resource-env-ref-name>
    <resource-env-ref-type>javax.enterprise.inject.spi.BeanManager</resource-env-ref-type>
  </resource-env-ref>
----

That should be it so when you start up your jetty distribution with the webapp you should see output similar to the following (providing your logging is the default configuration):

[source, screen, subs="{sub-order}"]
....
2015-06-18 12:13:54.924:INFO::main: Logging initialized @485ms
2015-06-18 12:13:55.231:INFO:oejs.Server:main: jetty-9.3.1-SNAPSHOT
2015-06-18 12:13:55.264:INFO:oejdp.ScanningAppProvider:main: Deployment monitor [file:///tmp/cdi-demo/webapps/] at interval 1
2015-06-18 12:13:55.607:WARN:oeja.AnnotationConfiguration:main: ServletContainerInitializers: detected. Class hierarchy: empty
Jun 18, 2015 12:13:55 PM org.jboss.weld.environment.servlet.EnhancedListener onStartup
INFO: WELD-ENV-001008: Initialize Weld using ServletContainerInitializer
Jun 18, 2015 12:13:55 PM org.jboss.weld.bootstrap.WeldStartup <clinit>
INFO: WELD-000900: 2.2.9 (Final)
Jun 18, 2015 12:13:55 PM org.jboss.weld.environment.servlet.deployment.WebAppBeanArchiveScanner scan
WARN: WELD-ENV-001004: Found both WEB-INF/beans.xml and WEB-INF/classes/META-INF/beans.xml. It's not portable to use both locations at the same time. Weld is going to use file:/tmp/jetty-0.0.0.0-8080-cdi-webapp.war-_cdi-webapp-any-8161614308407422636.dir/webapp/WEB-INF/beans.xml.
Jun 18, 2015 12:13:55 PM org.jboss.weld.bootstrap.WeldStartup startContainer
INFO: WELD-000101: Transactional services not available. Injection of @Inject UserTransaction not available. Transactional observers will be invoked synchronously.
Jun 18, 2015 12:13:55 PM org.jboss.weld.interceptor.util.InterceptionTypeRegistry <clinit>
WARN: WELD-001700: Interceptor annotation class javax.ejb.PostActivate not found, interception based on it is not enabled
Jun 18, 2015 12:13:55 PM org.jboss.weld.interceptor.util.InterceptionTypeRegistry <clinit>
WARN: WELD-001700: Interceptor annotation class javax.ejb.PrePassivate not found, interception based on it is not enabled
Jun 18, 2015 12:13:56 PM org.jboss.weld.bootstrap.MissingDependenciesRegistry handleResourceLoadingException
Jun 18, 2015 12:13:56 PM org.jboss.weld.environment.servlet.WeldServletLifecycle findContainer
INFO: WELD-ENV-001002: Container detection skipped - custom container class loaded: org.jboss.weld.environment.jetty.JettyContainer.
Jun 18, 2015 12:13:56 PM org.jboss.weld.environment.jetty.JettyContainer initialize
INFO: WELD-ENV-001200: Jetty 7.2+ detected, CDI injection will be available in Servlets and Filters. Injection into Listeners should work on Jetty 9.1.1 and newer.
Jun 18, 2015 12:13:56 PM org.jboss.weld.environment.servlet.Listener contextInitialized
INFO: WELD-ENV-001006: org.jboss.weld.environment.servlet.EnhancedListener used for ServletContext notifications
Jun 18, 2015 12:13:56 PM org.jboss.weld.environment.servlet.EnhancedListener contextInitialized
INFO: WELD-ENV-001009: org.jboss.weld.environment.servlet.Listener used for ServletRequest and HttpSession notifications
2015-06-18 12:13:56.535:INFO:oejsh.ContextHandler:main: Started o.e.j.w.WebAppContext@6574b225{/cdi-webapp,file:///tmp/jetty-0.0.0.0-8080-cdi-webapp.war-_cdi-webapp-any-8161614308407422636.dir/webapp/,AVAILABLE}{/cdi-webapp.war}
2015-06-18 12:13:56.554:INFO:oejs.ServerConnector:main: Started ServerConnector@7112f81c{HTTP/1.1,[http/1.1]}{0.0.0.0:8080}
2015-06-18 12:13:56.587:INFO:oejus.SslContextFactory:main: x509={jetty.eclipse.org=jetty} wild={} alias=null for SslContextFactory@3214ee6(file:///tmp/cdi-demo/etc/keystore,file:///tmp/cdi-demo/etc/keystore)
2015-06-18 12:13:56.821:INFO:oejs.ServerConnector:main: Started ServerConnector@69176a9b{SSL,[ssl, http/1.1]}{0.0.0.0:8443}
2015-06-18 12:13:56.822:INFO:oejs.Server:main: Started @2383ms

....

For use with the jetty-maven-plugin, the best idea is to make the org.jboss.weld.servlet:weld-servlet artifact a _plugin_ dependency (__not__ a webapp dependency), then follow step 2 above.