how many interceptor method in a Bean class ?

[Sanju Thomas]

Section 12.3 of the EJB core specs says that we can have only one @AroundInvoket method in a class.

AroundInvoke methods may be defined on superclasses of the bean class or interceptor classes.
However, only one AroundInvoke method may be present on a given class. An AroundInvoke
method cannot be a business method of the bean.

But I could write two AroundInvoke methods in the Bean class, and JBoss 5.0 did not complain anything about it!.

Code is gien below.

Remote interface

   

package mine.test.ejb;

import javax.ejb.Remote;

@Remote
public interface IBean { 

	public void businessMethod();
	public void businessMethodOne();
}

Bean Class

  
package mine.test.ejb;

import javax.ejb.Stateless;
import javax.interceptor.AroundInvoke;
import javax.interceptor.InvocationContext;


@Stateless

public class MyBean implements IBean{

	
	public void businessMethod() 
	{
		System.out.println("Business Method");
		
	}
	
	public void businessMethodOne()
	{
		System.out.println("Business method one");
	}
	

	@AroundInvoke
	public Object interceptorMethod(InvocationContext ie) throws Exception
	{
		System.out.println("interceptorMethod is called");
		return ie.proceed();
	}

	
	@AroundInvoke
	public Object interceptorMethodOne(InvocationContext ie) throws Exception
	{
		System.out.println("interceptorMethodOne is called");
		return ie.proceed();
	}

}


  

Client code

   

package mine.test.ejb.client;

import java.util.Properties;
import javax.naming.*;

import mine.test.ejb.*;

public class EjbClient 
{
	
	public static void main(String args[]) throws NamingException
	{
		Properties properties = new Properties();			
		properties.put(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");		
		properties.put("java.naming.factory.url.pkgs", "org.jboss.naming:org.jnp.interfaces");
		properties.put(Context.PROVIDER_URL, "jnp://localhost:1099");
		
		IBean ibean = (IBean)new InitialContext(properties).lookup("MyBean/remote");

		ibean.businessMethod();
		ibean.businessMethodOne();

	}

}

 

JBoss console output
------------------------

13:01:16,381 INFO [STDOUT] interceptorMethod is called
13:01:16,381 INFO [STDOUT] interceptorMethodOne is called
13:01:16,381 INFO [STDOUT] Business Method
13:01:16,427 INFO [STDOUT] interceptorMethod is called
13:01:16,427 INFO [STDOUT] interceptorMethodOne is called
13:01:16,427 INFO [STDOUT] Business method one


Whats happening here ?? Am I doing something wrong ? or JBoss is not following spec ? Both interceptor methods are permitted and both are getting executed. Please help.

[Deepika Joshi]

Consider the following code from EJB 3 In Action

   
@Stateless
public class PlaceBidBean implements PlaceBid {
      ...
     @Interceptors(ActionBazaarLogger.class)
     public void addBid(Bid bid) {
          ...
     }
}

public class ActionBazaarLogger {
     @AroundInvoke
     public Object logMethodEntry(InvocationContext invocationContext) throws Exception {
          System.out.println("Entering method: ” + invocationContext.getMethod().getName());
          return invocationContext.proceed();
     }
} 

When you use @Interceptors you mention class name (e.g. ActionBazaarLogger.class) (and not method name),
If you have more than one @AroundInvoke in a class then how would you use them (or either of them)?

[Omar Al Kababji]

Well the specifications provided by SUN says that you must have only one method in an interceptor taged with the @AroundInvoke annotation, however it seems that JBoss didn't follow this specification. many times Applicatin Servers modifiy a bit some of the specifications.

[Christophe Verré]

The spec says "However, only one AroundInvoke method may be present on a given class. ", not "must be", which also means : "You're responsible for your mistakes"

Here is what Glassfish gave me :

interceptorMethodOne is called
Business Method
interceptorMethodOne is called
Business Method One

You can see that only one interceptor method is called. I also tried to put the interceptor method in a separate class :

package com.chris.ejbs.interceptor;

import javax.interceptor.AroundInvoke;
import javax.interceptor.InvocationContext;

public class MyInterceptor {

	@AroundInvoke  
	public Object interceptorMethod(InvocationContext ie) throws Exception {
		System.out.println("interceptorMethod is called");  
		return ie.proceed();  
	}  
	
	@AroundInvoke  
	public Object interceptorMethodOne(InvocationContext ie) throws Exception {
		System.out.println("interceptorMethodOne is called");
		return ie.proceed();  
	}  

}

This time, it gave me :

interceptorMethod is called
Business Method
interceptorMethod is called
Business Method One

[Sanju Thomas]

Test result from Glasfish is also strange. When we had @AroundInvoke interceptor methods inside the bean the "interceptorMethodOne" got invoked, when we moved to a seperate interceptor class the "interceptorMethod" got invoked.

anyways what should I answer for the exam ?

According to spec we can have only one @AroundInvoke method in a class. Whether its in bean class or in sperate interceptor class. is that correct ?

[Christophe Verré]

anyways what should I answer for the exam ?

Only one method allowed in the same class.

[Sanju Thomas]

Thanks Christophe.