Book Image

JBoss Weld CDI for Java Platform

By : Kenneth Finnigan
Book Image

JBoss Weld CDI for Java Platform

By: Kenneth Finnigan

Overview of this book

CDI simplifies dependency injection for modern application developers by taking advantage of Java annotations and moving away from complex XML, while at the same time providing an extensible and powerful programming model. "JBoss Weld CDI for Java Platform" is a practical guide to CDI's dependency injection concepts using clear and easy-to-follow examples. This will help you take advantage of the power behind CDI, as well as providing a firm understanding of how to use it within your applications. "JBoss Weld CDI for Java Platform" covers all the major aspects of CDI, breaking it down into understandable pieces. This book will take you through many examples of how these concepts can be utilized, helping you get up and running quickly and painlessly. "JBoss Weld CDI for Java Platform" gives you an insight into the different scopes provided by CDI and the use cases for which each has been designed. You will learn everything about dependency injection, scopes, events, producers, and more from JBoss Weld CDI, as well as how producers can create new beans for consumption within your application. You will also learn how to build a real world application with CDI using JSF and AngularJS for different web interfaces.
Table of Contents (17 chapters)
JBoss Weld CDI for Java Platform
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Injection into non-container managed instances


Sometimes we have a class that has CDI injection point on it but it isn't instantiated by the container, so it is not available for injection to be performed on it. An example of this is a portlet class that needs to inject beans into itself, but a portlet class is instantiated and controlled by a portlet container so Weld is unable to perform injection on it.

In our example, the portlet class would be classified as a non-container managed instance, as the instance of the portlet class is not created by Weld and therefore not managed by it either.

We can ask Weld to perform injection on our portlet class instance as follows:

// get the BeanManager, from JNDI in this example
BeanManager beanManager = (BeanManager)
  new InitialContext().lookup("java:comp/BeanManager");

// create an AnnotatedType for our class
AnnotatedType<MyPortlet> portletType =
    beanManager.createAnnotatedType(myPortlet.getClass());

// create an InjectionTarget
InjectionTarget...