Beginning Java EE 6 with GlassFish 3, Second Edition

CHAPTER 8 ■ CALLBACKS AND INTERCEPTORSFigure 8-4. A call to a business method being interceptedMethod InterceptorsListing 8-3 defines an interceptor that is only available for CustomerEJB. But most of the time you want toisolate a cross-cutting concern into a separate class and tell the container to intercept the calls onseveral session beans. Logging is a typical example of a situation when you want all the methods of allyour EJBs to log entering and exiting messages. To specify an interceptor, you need to develop a separateclass and instruct the container to apply it on a specific bean or bean’s method.To share some code among multiple beans, let’s take the logMethod() from Listing 8-3 and isolate itin a separate class as shown in Listing 8-4. As you can see, LoggingInterceptor is a simple POJO that hasa method annotated with @AroundInvoke.Listing 8-4. An Interceptor Class Logging a Method on Entering and Exitingpublic class LoggingInterceptor {private Logger logger = Logger.getLogger("com.apress.javaee6");@AroundInvokepublic Object logMethod(InvocationContext ic) throws Exception {logger.entering(ic.getTarget().toString(), ic.getMethod().getName());try {return ic.proceed();} finally {logger.exiting(ic.getTarget().toString(), ic.getMethod().getName());}}}247