Applicaction configuration in Java EE 6 using CDI - a simple example

CDI (Contexts and Dependency Injection for the Java EE platform) is defined in JSR-299 and enhances support for dependency injection in Java EE 6. The more I use CDI the more I like it...However, I couldn't find a simple example of how to configure your application with CDI by reading configuration attributes from a file. Here is an example of how it can be done: Specifying injection points Injection points are places where CDI will inject values automatically. They can be used to receive references to container objects like PersistenceUnit or Transaction manager, and also to receive configuration values. One specifies a injection point by annotating a field, constructor parameter or method parameter with the @Inject annotation. When the container finds this annotation it will try to find (or construct) a value to be stored at this point. Just using @Inject is not enough for configuration, because the container will not know where we want it to get the configuration from. We will need to create a configuration factory, but before that we need to define an additional annotation to provide a hint about where the value will be coming from. This annotation is called a Qualifier annotation exactly because it qualifies the information to be injected. In this example we will create the @Config annotation: @Qualifier @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.TYPE, ElementType.METHOD, ElementType.FIELD, ElementType.PARA...

Date: May, 18 2010
Url: http://www.java.net/blog/jjviana/archive/2010/05/18/applicaction-configuration-java-ee-6-using-cdi-simple-example

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