Permanent interceptor

[aleksab]

Scenario: A JBoss server with several beans deployed. Several client access these beans.

Goal: Intercept EVERY call from a client to a bean, and process some global information, before letting the call proceed or terminate. The objects/class intercepting the call to the various bean must be able to communicate with each other, OR be a common object.

Problem: What is the best and possible approaches to this?

I've thought about adding a new AOP layer, and let each bean ie. add a notation. However, each bean would then have it's own instance fo the aop class, right? I want the aop interceptor to make decisions based on all incoming calls.

[jc7442]

I have done something like this to catch unexpected exception and perform some action before sending the exception to the client.
I use interceptor taht I have added in ejb3-interceptors-aop.xml.

I'm quite happy with that.

[aleksab]

Sounds like the way to go.

Do you have any tutorial or examples on how to do this? Have search google and the jboss sites, without finding anything really usefull.

[jc7442]

Hi,

I'm not sure you can simply add your own domain in the ejb3 interceptors. I just connect on existing one.
If your need is to add your own domain check AOP documentation. From what I remenber it is explain but not so simple to implement.

It looks like that :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE aop PUBLIC
"-//JBoss//DTD JBOSS AOP 1.0//EN"
"http://www.jboss.org/aop/dtd/jboss-aop_1_0.dtd">


...


<!--################################################### -->
<!--My Interceptor-->


<!--typedef name="bmx" expr="class(@javax.ejb.Remote) OR class(@javax.ejb.Local)"/-->

<!-- FIN MyInterceptor-->
<!-- ################################################### -->




<!-- ################################################### -->
<!-- My Interceptor-->

<!--interceptor-ref name="fr.biomerieux.interceptor.ExecutionTimeInterceptor"/-->
<interceptor-ref name="fr.biomerieux.interceptor.ExceptionHanlderInterceptor"/>

<!-- FIN My Interceptor-->
<!-- ################################################### -->


<interceptor-ref name="org.jboss.ejb3.asynchronous.AsynchronousInterceptor"/>
...



<!-- ################################################### -->
<!-- My Interceptor-->

<!--interceptor-ref name="fr.biomerieux.interceptor.ExecutionTimeInterceptor"/-->
<interceptor-ref name="fr.biomerieux.interceptor.ExceptionHanlderInterceptor"/>

<!-- FIN My Interceptor-->
<!-- ################################################### -->

<interceptor-ref name="org.jboss.ejb3.asynchronous.AsynchronousInterceptor"/>
...

And a intercptor:

public class ExecutionTimeInterceptor implements Interceptor {
/**
* Version number
*/
private final Logger LOGGER = Logger.getLogger(ExecutionTimeInterceptor.class
.getName());

/**
* Log the elapsed time of the execution of a method
*/
public Object invoke(Invocation invocation) throws Throwable {
long start = System.currentTimeMillis();
try {
return invocation.invokeNext();
} finally {
long end = System.currentTimeMillis();
MethodInvocation methodInvocation = (MethodInvocation) invocation;
Method m = methodInvocation.getMethod();
LOGGER.fine(MessageFormat.format(MESSAGE.METHOD_EXECUTION,
new Object[] { m.getDeclaringClass().getName(), m.getName(),
((end - start) / 1000.) }));
}
}

/**
* Return the name of the interceptor
*/
public String getName() {
return ExecutionTimeInterceptor.class.getName();
}

}