JPz’log

During the christmas break, I took an hour or so to play with Groovy and EJBs. EJB 3 are very easy to use (especially compared to what they used to be before that) so I decided to investigate how I could make them even simpler to use with Groovy.

Indeed, Groovy shares mostly the same meta-model as Java and you can easily mix Java and Groovy code in the same project (actually you can put .java and .groovy files side-by-side in your packages).

I opted for a simple hello-word style of project using Groovy 1.5 and GlassFish v2 ur1.

I started with a single HelloEJB.groovy file to host both the EJB remote interface and implementation as a stateless session bean:

package ejb
 
import javax.ejb.Remote
import javax.ejb.Stateless
 
@Remote
interface HelloRemote
{
    String hello()
}
 
@Stateless
class HelloEJB implements HelloRemote
{
    String hello()
    {
        return "Hello world!"
    }
}

The Groovy compiler takes care of generating 2 .class files (one for the interface and one for the class). Nice

Then I packaged this inside an EAR having groovy-all-1.5.jar so that GlassFish could make the Groovy runtime available to the EJB. Then I wrote this simple remote client to test it:

import javax.naming.InitialContext
 
def ctx = new InitialContext()
def ejb = ctx.lookup("ejb.HelloRemote")
 
println ejb.hello()

For this client to work, you need to put appserv-rt.jar from GlassFish in your classpath. Also, you will need to tweak a jndi.properties file at the root of your client classpath if you are not using the default GlassFish ports for your target domain.

I guess I can now save quite a lot of time using Groovy to implement EJBs

Disclaimer: I am dynamic-languages agnostic as I use Python, Ruby and Groovy for various things and I like them all. Really!