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

Custom scopes


Creating a custom scope is usually the preserve of framework developers, but it can be beneficial for us to understand how they can be created as we may find the need to write one in the future.

To create a new pseudo scope we use the following code:

@Scope
@Retention(RUNTIME)
@Target( { METHOD, TYPE, FIELD } )
public @interface MyPseudoScope {}

But as it is unlikely that we will need to create a pseudo scope, the following is how to create a new normal scope:

@NormalScope
@Retention(RUNTIME)
@Target( { METHOD, TYPE, FIELD } )
public @interface MyNonPassivatingScope {}

As the default value for the passivating attribute on @NormalScope is false, we don't need to set it if we want to define a non-passivation capable scope.

Either of these scopes could then be used just as any other of the built-in scopes provided in CDI by annotating a bean with the scope annotation.

Creating the scope is the easy part; the difficult task is to implement a Context interface for the new scope. The Context...