Document Information


Part I Introduction

1.  Overview

2.  Using the Tutorial Examples

Part II The Web Tier

3.  Getting Started with Web Applications

4.  JavaServer Faces Technology

5.  Introduction to Facelets

6.  Expression Language

7.  Using JavaServer Faces Technology in Web Pages

8.  Using Converters, Listeners, and Validators

9.  Developing with JavaServer Faces Technology

10.  JavaServer Faces Technology: Advanced Concepts

11.  Using Ajax with JavaServer Faces Technology

12.  Composite Components: Advanced Topics and Example

13.  Creating Custom UI Components and Other Custom Objects

14.  Configuring JavaServer Faces Applications

15.  Java Servlet Technology

16.  Uploading Files with Java Servlet Technology

17.  Internationalizing and Localizing Web Applications

Part III Web Services

18.  Introduction to Web Services

19.  Building Web Services with JAX-WS

20.  Building RESTful Web Services with JAX-RS

21.  JAX-RS: Advanced Topics and Example

Part IV Enterprise Beans

22.  Enterprise Beans

23.  Getting Started with Enterprise Beans

24.  Running the Enterprise Bean Examples

25.  A Message-Driven Bean Example

26.  Using the Embedded Enterprise Bean Container

27.  Using Asynchronous Method Invocation in Session Beans

Part V Contexts and Dependency Injection for the Java EE Platform

28.  Introduction to Contexts and Dependency Injection for the Java EE Platform

29.  Running the Basic Contexts and Dependency Injection Examples

30.  Contexts and Dependency Injection for the Java EE Platform: Advanced Topics

Using Alternatives in CDI Applications

Using Specialization

Using Producer Methods, Producer Fields, and Disposer Methods in CDI Applications

Using Producer Methods

Using Producer Fields to Generate Resources

Using a Disposer Method

Using Predefined Beans in CDI Applications

Using Events in CDI Applications

Defining Events

Using Observer Methods to Handle Events

Firing Events

Using Decorators in CDI Applications

Using Stereotypes in CDI Applications

31.  Running the Advanced Contexts and Dependency Injection Examples

Part VI Persistence

32.  Introduction to the Java Persistence API

33.  Running the Persistence Examples

34.  The Java Persistence Query Language

35.  Using the Criteria API to Create Queries

36.  Creating and Using String-Based Criteria Queries

37.  Controlling Concurrent Access to Entity Data with Locking

38.  Using a Second-Level Cache with Java Persistence API Applications

Part VII Security

39.  Introduction to Security in the Java EE Platform

40.  Getting Started Securing Web Applications

41.  Getting Started Securing Enterprise Applications

42.  Java EE Security: Advanced Topics

Part VIII Java EE Supporting Technologies

43.  Introduction to Java EE Supporting Technologies

44.  Transactions

45.  Resources and Resource Adapters

46.  The Resource Adapter Example

47.  Java Message Service Concepts

48.  Java Message Service Examples

49.  Bean Validation: Advanced Topics

50.  Using Java EE Interceptors

Part IX Case Studies

51.  Duke's Bookstore Case Study Example

52.  Duke's Tutoring Case Study Example

53.  Duke's Forest Case Study Example



Using Interceptors in CDI Applications

An interceptor is a class used to interpose in method invocations or lifecycle events that occur in an associated target class. The interceptor performs tasks, such as logging or auditing, that are separate from the business logic of the application and are repeated often within an application. Such tasks are often called cross-cutting tasks. Interceptors allow you to specify the code for these tasks in one place for easy maintenance. When interceptors were first introduced to the Java EE platform, they were specific to enterprise beans. On the Java EE 6 platform you can use them with Java EE managed objects of all kinds, including managed beans.

For information on Java EE interceptors, see Chapter 50, Using Java EE Interceptors.

An interceptor class often contains a method annotated @AroundInvoke, which specifies the tasks the interceptor will perform when intercepted methods are invoked. It can also contain a method annotated @PostConstruct, @PreDestroy, @PrePassivate, or @PostActivate, to specify lifecycle callback interceptors, and a method annotated @AroundTimeout, to specify EJB timeout interceptors. An interceptor class can contain more than one interceptor method, but it must have no more than one method of each type.

Along with an interceptor, an application defines one or more interceptor binding types, which are annotations that associate an interceptor with target beans or methods. For example, the billpayment example contains an interceptor binding type named @Logged and an interceptor named LoggedInterceptor.

The interceptor binding type declaration looks something like a qualifier declaration, but it is annotated with javax.interceptor.InterceptorBinding:

@Target({METHOD, TYPE})
public @interface Logged {

An interceptor binding also has the java.lang.annotation.Inherited annotation, to specify that the annotation can be inherited from superclasses. The @Inherited annotation also applies to custom scopes (not discussed in this tutorial), but does not apply to qualifiers.

An interceptor binding type may declare other interceptor bindings.

The interceptor class is annotated with the interceptor binding as well as with the @Interceptor annotation. For an example, see The LoggedInterceptor Interceptor Class.

Every @AroundInvoke method takes a javax.interceptor.InvocationContext argument, returns a java.lang.Object, and throws an Exception. It can call InvocationContext methods. The @AroundInvoke method must call the proceed method, which causes the target class method to be invoked.

Once an interceptor and binding type are defined, you can annotate beans and individual methods with the binding type to specify that the interceptor is to be invoked either on all methods of the bean or on specific methods. For example, in the billpayment example, the PaymentHandler bean is annotated @Logged, which means that any invocation of its business methods will cause the interceptor’s @AroundInvoke method to be invoked:

public class PaymentHandler implements Serializable {...}

However, in the PaymentBean bean, only the pay and reset methods have the @Logged annotation, so the interceptor is invoked only when these methods are invoked:

public String pay() {...}

public void reset() {...}

In order for an interceptor to be invoked in a CDI application, it must, like an alternative, be specified in the beans.xml file. For example, the LoggedInterceptor class is specified as follows:


If an application uses more than one interceptor, the interceptors are invoked in the order specified in the beans.xml file.