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

Advanced interceptors


These next sections will delve deeper into interceptor binding types to explain more advanced use cases of them. We will cover binding types with members, how to combine different interceptors for a single use, and how binding types can be inherited.

Interceptor binding types with members

Just as with qualifier annotations, we can also add members to interceptor binding types too, such as:

@InterceptorBinding
@Target( { METHOD, TYPE } )
@Retention( RUNTIME )
public @interface Audited {
  boolean logToFile() default false;
}

With the binding type we just created, we need to create a new interceptor that matches the situation of logToFile being true, as CDI uses the member as a means for choosing a different interceptor implementation. For our preceding interceptor binding type, the implementation would be:

@Audited( logToFile = true )
@Interceptor
public class AuditFileInterceptor {
  @AroundInvoke
  public Object auditMethod(InvocationContext ctx)
  throws Exception
  ...