Looking for ideal tools and techniques for building applications is like a quest for the holy grail. In this pursuit we’re looking for features like simplicity, performance, reusability, testability, hot-deployment, and embeddability. In an attempt to find the holy grail of software development we'll mount up and try to assert whether EJB is a step forward or backward on our path. We'll go through a couple of aspects of an utopian software component in terms of performance/scalability and testability. What if we opt for a simple direct-call solutions? What if we invite aliens to help testing EJBs? Class hot-deploy, a fluffy white rabbit? What if we snuggle up real close to our EJBs in an embedded environment?

1. 1
How to cuddle your EJBs
Carlo de Wolf
EJB 3 Product Lead
JBoss by Red Hat
October 2010

2. 2
Agenda
● Quest for The Holy Grail
● EAP
● Why use EJB?
– Simple
– Predictable
– Re-usable
– Testable
● Road-map

3. 3
Quest for The Holy Grail
● Looking for software components that are:
– Simple
– Predictable
– Re-usable
– Testable
● Also
– Performant

4. 4
Enterprise Application Platform
● A fork of AS 5
● Plus functional patches
● Plus performance patches
● Plus support
● Some bits available through Plugin 1.0.19

5. 5
Why use EJB(tm)
?
● Allow rapid development of reusable
business components
● Using an easy infrastructure which does:
– Memory management
– Remote invocation
– Thread management
● Thus having a predictable QoS

6. 6
What is an EJB(tm)
?
● It's not a POJO!
● It consists of a class + interceptor classes
+ interfaces
● Construction is different
● Invocation is different
● It's an assembly with one or more views

7. 7
Quest for The Holy Grail
● Looking for software components that are:
– Simple
– Predictable
– Re-usable
– Testable
● Also
– Performant

8. 8
Simplicity
● Create an EJB with a remote business
view
● Create an EJB archive
● Deploy it

9. 9
Creating an EJB
● Learn how to code EJBs with Andrew's
book: Enterprise JavaBeans 3.1
– ISBN: 978-0-596-15802-6
– Develop your first EJBs with a
hands-on walkthrough of
EJB 3.1 concepts

10. 10
Creating an EJB archive
● Use Ant to create an archive
<jar jarfile=”${build.lib}/myfirstejb.jar”>
<fileset dir=”${build.class}”/>
</jar>
● Or use Maven

11. 11
Deploying an archive
● Copy into deploy
$ cp myfirstejb.jar $JBOSS_HOME/server/default/deploy/
● Use the MainDeployer
MbeanServerConnection conn =
iniCtx.lookup(“jmx/invoker/RMIAdaptor”);
conn.invoke(“jboss.system:service=MainDeployer”,
“deploy”, new URL(“file:myfirstejb.jar”));

12. 12
Quest for The Holy Grail
● Looking for software components that are:
– Simple
– Predictable
– Re-usable
– Testable
● Also
– Performant

13. 13
Dynamic Code Changing
● EJBTHREE-1096: Make SLSB and SFSB
hot deployable for RAD.
● Allow changing functionality / invariants
● Allow changes in the EJB structure
● Compiling (Deploying) vs Interpreted

14. 14
Bean State
● Bean State is governed by invariants
@Stateful
public class ConsentWizard
{
private Date birthdate;
public void setBirthday(Date date)
{
if(age(date) < 18)
throw new IllegalStateException("Minors not allowed");
this.birthdate = date;
}
}
● Changing an invariant leaves artifacts
● Bean State has become non-deterministic

15. 15
Application State
● Application state is determined by the
assembly of all components
@Stateful
public class ConsentWizard implements RemoteWizard
{
}
public class SomeServletThingy
{
@EJB RemoteWizard wizard;
}
● Changing component structure may leave
application undeployable

16. 16
Deploying is like Compiling
● It checks whether the application is
deployable
● It sets up a clean slate to begin tests from
● So, Dynamic Code Changing is a fluffy
white rabbit. Looks cute, but will kill you in
the end.

17. 17
Quest for The Holy Grail
● Looking for software components that are:
– Simple
– Predictable
– Re-usable
– Testable
● Also
– Performant

18. 18
Separation of Concerns
● By making aspects configurable and
manageable
● Security
● Transaction Management
● Remoting
● Interceptors (now separated!)
● Persistence (separated into JPA)

19. 19
Spec EJB 3.1 Async
● A re-usable component separates
concerns
● Brings an application developer
requirement to the bean developer
● Ergo doesn't make for re-usable
components

20. 20
JBoss EJB 3.1 Async
● A callers functional concern
● If the caller resides in the same VM, let the
EJB manage it

21. 21
Quest for The Holy Grail
● Looking for software components that are:
– Simple
– Predictable
– Re-usable
– Testable
● Also
– Performant

22. 22
Test it using a remote view
● Create an archive, deploy it, then call it
public class RemoteTestCase
{
@Test
public void test() throws NamingException
{
MyFirstView bean = (MyFirstView) iniCtx.lookup("MyFirstBean/remote");
String result = bean.doSomething();
assertEquals("done", result);
}
}

23. 23
Assembled Directory
● Use VFS 2
AssembledDirectory jar =
AssembledContextFactory.getInstance().create("test.jar");
jar.addClass(GreetingsBean.class);
jar.addClass(Greetings.class);
● The venerable JBoss Embeddable
Bootstrap.getInstance().deploy(jar);
● JBoss Reloaded Embedded prototype
VFSDeployment deployment =
VFSDeploymentFactory.getInstance().createVFSDeployment(root);
mainDeployer.deploy(root);
● EJB 3.1 Embeddable prototype
EJBContainer container = EJBContainer.createEJBContainer();
on(container).deploy(deployment(jar));

24. 24
ShrinkWrap
● Easily build an archive
JavaArchive jar = ShrinkWrap.create(JavaArchive.class, "test.jar")
.addClasses(GreetingsBean.class, Greetings.class);
File tempFile = File.createTempFile("test", ".jar");
jar.as(ZipExporter.class).exportZip(tempFile, true);
URL url = tempFile.toURI().toURL();
● Deploy the archive
MbeanServerConnection conn = iniCtx.lookup("jmx/invoker/RMIAdaptor");
conn.invoke("jboss.system:service=MainDeployer", "deploy", url);
● See it in action
$ git clone git://github.com/jbossejb3/jboss-ejb3-timerservice.git
$ cd jboss-ejb3-timerservice
$ mvn install

25. 25
EJB 3.1 Embeddable
● By spec only does local session beans
● You want more services, so ultimately a
full Application Server
● Two solutions:
– Paravirtualized, not standalone
– JBoss Embedded

26. 26
Arquillian
● Or we could go to the server
@RunWith(Arquillian.class)
public class GreetingManagerTest {
@Deployment
public static JavaArchive createDeployment() {
return ShrinkWrap.create(JavaArchive.class, "test.jar")
.addClasses(GreetingsBean.class, Greetings.class);
}
@EJB
private Greetings alien;
@Test
public void shouldGreetUser() throws Exception {
String name = "Earthlings";
assertEquals("Hello, " + name, alien.greet(name));
}
}

27. 27
Arquillian #2
● Access to local views
● Debug my EJBs and unit test
– Breakpoints
– Step through
– Happens on the VM running the Server
● JBoss AS becomes an 'OS' resource
– No worry about Server lifecycle / startup time

28. 28
ShrinkWrap + Arquillian
● The Aliens love any container
● Complete separation of concerns

29. 29
Road-map
● EAP 6 will do EJB 3.1
● AS 6 CR1 time-box closes Nov 16th
● AS 7 M1 is coming up
● Bug reports / requests can end up in a
milestone, get on the band-wagon.

30. 30
EJB 4
● More separation of concerns
● Concrete aspects of Managed Beans?
● CDI Extension?

31. 31
How to cuddle your EJBs?
● Don't try to bring the EJBs to you.
● Go to the EJBs.
● Use ShrinkWrap & Arquillian for your
travels!

32. Q & A
http://jboss.org/ejb3
http://jboss.org/shrinkwrap
http://jboss.org/arquillian