Using EJB Interceptors — Part 2

In the first part of this series of posts we looked at the around-invoke interceptors supported by EJB 3.1. In this post we will mention method interceptors.
EJB 3.1 provides support for defining method level interceptors through the use of the @Interceptors annotation. Using this annotation it is possible to share common interceptors across different business methods.

The @Interceptors annotation declares an ordered list of interceptors for a target class or method of a target class. To register an interceptor for a method:

@Interceptors(LoggingInterceptor.class)
    public Float calculate(Float x, Float y) throws IllegalArgumentException {
        return 2 * x + y;
}

It is also possible to register multiple interceptors for a business method. To register two interceptors to a business method:

@Interceptors({LoggingInterceptor.class, SecurityInterceptor.class})
 public void someBusinessMethod(SomeParameter param) { ... }

In order to intercept all business method calls of a bean, the @Interceptors annotation can be used at the class-level:

@Stateless
@Interceptors(LoggingInterceptor.class)
public class SimpleSessionBean implements SimpleSessionBeanRemote {

Finally to exclude a method from the use of class-level interceptors we use the @ExcludeClassInterceptors annotation:

@Stateless
@Interceptors(LoggingInterceptor.class)
public class SimpleSessionBean implements SimpleSessionBeanRemote {

@ExcludeClassInterceptors
public void placeOrder(Order o){
…
}
//other methods
}

The output of the interceptor is shown below:

[#|intercepting method call|#]
[#|Processing call calculate@com.sirius.test.SimpleSessionBean@1779dfb|#]
[#|=>1.0|#]
[#|=>2.0|#]
[#|Done with calculate@com.sirius.test.SimpleSessionBean@1779dfb|#]

You can download the code for the application here. The application is tested on Glassfish v3.0.