Create local interface of the stateless session bean
Hi,
Can somebody let me know how to create a local interface of the stateless session bean. The following code is not working for me.
ProductAdminSessionLocal pas;
try{
final Context context = getInitialContext();
pas = (ProductAdminSessionLocal)context.lookup("ProductAdminSessionLocal");
}catch (NamingException ne){
thrownew WarningException(new CatalogHelper("ITOOLS_900023"));
}
private Context getInitialContext()throws UnknownException{
try{
returnnew InitialContext();
}catch (NamingException ne){
thrownew UnknownException (new CatalogHelper("ITOOLS_900024", ne.getMessage()));
}
}
Thanks in advance
-raju
[1570 byte] By [
svgkrajua] at [2007-11-26 15:06:15]
# 1
EJBLocalHome home;
try {
home = (EJBLocalHome) getInitialContext().lookup(jndiHomeName);
log.info("Local jndiHomeName "+jndiHomeName+" look up successful");
} catch (Throwable e) {
throw new GeneralException(e);
}
Where "jndiHomeName" is EJB JNDI (e.g. mysite/ejb/local/MyEJB), look this up in application server JNDI tree after deployment.
Then use "home.create()" to get local interface.
# 2
> Where "jndiHomeName" is EJB JNDI (e.g.
> mysite/ejb/local/MyEJB), look this up in application
> server JNDI tree after deployment.
This is not correct. Unfortunately there is a misconception that it is portable
to access ejb dependencies from the global namespace, mostly because
some application servers, e.g. JBoss, support it.
The portable way to access all ejb references, whether local or remote, is
through the private component namespace -- java:comp/env.In the
local case, you need to define an ejb-local-ref and look up its
ejb-ref-name via java:comp/env. An alternative for Java EE 5 is
to use the @EJB annotation and have the EJBLocalHome injected.
--ken
>
> Then use "home.create()" to get local interface.
# 3
Hi,
Thank you for your replies. I am using OC4J (10.1.3.1) and EJB 3 in my application. I am able to do successful lookup for remote inteface mentioning context.lookup("ProductAdminSession")
. Apart from this it is not required to have home interace as per EJB 3.0. Is it that lookup is something different to create local interfaces?
regds
-raju
# 4
Hi Raju,
If the lookup is happening within a Java EE component, it is always preferable to use
the portable approach, which means accessing an ejb dependency via java:comp/env
or via @EJB injection.That is true regardless of whether local or remote interfaces
are being used.
--ken
# 5
Ken,
Thanks for you reply. I changed the code as follows:
ProductAdminSessionLocal pas;
try {
final Context context = getInitialContext();
pas = (ProductAdminSessionLocal)this.getInitialContext().lookup("java:comp/env/ProductAdminSessionLocal");
} catch (NamingException ne) {
throw new WarningException(new CatalogHelper("ITOOLS_900023"));
}
Actually I am creating the local interface in another stateless session bean that is running in the same java EE component. I am getting the same naming exception again. Is it required to maintain web.xml even if the client of the sateless session bean is another session bean within the same java EE component?
regds
-raju
# 6
Small mistake in my last postpas = (ProductAdminSessionLocal)context.lookup("java:comp/env/ProductAdminSessionLocal");regds-raju
# 7
Hi Raju,
If the client of the stateless session bean is itself another session bean, then it is a
different component. It sounds like what you're saying is that both components
are part of the same application.In the case of EJB, the component environment
(java:comp/env) is private for each component. That means you need to define
the ejb-local-ref within the client component.
--ken
# 8
Hi,
I got it. The following code worked for me.
@EJB(name="ProductAdminSessionLocal", beanInterface=ProductAdminSessionLocal.class)
@Stateless(name="AdminSession")
@Remote(AdminSession.class)
public class AdminSessionBean {
....
private Context getInitialContext() throws UnknownException {
try {
return new InitialContext();
} catch (NamingException ne) {
throw new UnknownException (new CatalogHelper("ITOOLS_900024", ne.getMessage()));
}
}
ProductAdminSessionLocal pas;
try {
final Context context = getInitialContext();
pas = (ProductAdminSessionLocal)context.lookup("java:comp/env/ProductAdminSessionLocal");
} catch (NamingException ne) {
ne.printStackTrace();
throw new WarningException(new CatalogHelper("ITOOLS_900023", ne.getMessage()));
}
....
}
Thanks for your inputs.
regds
-raju
# 9
Hi Raju,
Glad it's working for you.One other thing to note is that if you do need
to lookup the ejb reference instead of using injection, EJB 3.0 defines a
simpler way than using the JNDI API. There is now a lookup() method
on the EJBContext interface. When using it, you bypass "java:comp/env",
so it would look like this :
// inject the EJB SessionContext
@Resource SessionContext sesCtx;
...
ProductAdminSessionLocal pas = (ProductAdminSessionLocal)
sesCtx.lookup("ProductAdminSessionLocal");
There are a number of advantages to this over the old approach :
1. You don't need to know about the JNDI InitialContext API.
2. You don't need to know about java:comp/env
3. The EJBContext.lookup method does not throw a checked exception so
you don't need a try-catch block around the lookup.
--ken
# 10
Hello Ken
I have an enterprise application with a ejb module. It has two packages, one contains a SessionBean with Local and Remote Interface.
The second package is a utils package which contains a ServiceLocator class. I use this class to lookup the Remote and Local Interfaces of my session beans. The lookup code for remote interface works fine but not for local interface. I tried the approach you mentioned but still that still gives a NullPointer Exception. Here is my code:
@Resource SessionContext sesCtx;
public void getLocal() throws Exception
{
MySessionLocal lc = (MySessionLocal ) sesCtx.lookup("MySessionLocal");
System.out.println(lc.findAllPlayers.size());
}
Here is my Session Bean:
@Stateful(name="SessionBean")
public class ManagerSessionBean implements MySessionRemote , MySessionLocal {
...}
What am i doing something wrong?
Thanks
null
Message was edited by:
rabbia
# 11
You'd simply use@EJB private MySessionLocal lc;instead of looking it up.
# 12
Java EE annotations are only supported on certain special container-managed classes
such as EJB bean classes, EJB interceptors, servlets, JSF managed beans, etc. If you
just have a plain utility class and define a Java EE annotation on it, the annotation will
be ignored.That's why you're getting the NPE.
Which other components are looking up the ManagerSessionBean?Are they EJBs
or web components?Only EJBs/web components in the same application as the
ManagerSessionBean can portably access its local EJB interface.
--ken
# 13
Hello
Here is the hierarchy:
ServerApplication
|_SessionPackage
sessionpackage.ManagerSessionBean
sessionpackage.MySessionLocal
sessionpackage.MySessionRemote
|_UtilsPackage
utilspackage.ServiceLocator
A ServerApplication.jar contains all the class files of classes mentioned above and is deplyed at the jboss server.
If I use this approach within any other SessionBean within ServerApplication.jar:
@EJB private MySessionLocal lc;
It works fine. But I cannot apply this approach in ServiceLocator since it is a plain java class. Thats why i used the approach i mentioned in my previous post.
Now lets say i need another jar file which contains some other session beans say App2.jar. App2.jar will also be deployed at the same place as ServerApplication.jar. So if i need to access ManagerSessionBean in some session bean of App2.jar, isnt it a better approach to use its local interface instead of a lookup for its remote interface? Thats why i was creating a ServiceLocator so that i can lookup remote and local interfaces of session beans.
What do you suggest is a better approach?
Thanks
Message was edited by:
rabbia
# 14
If components in module2 need portable local ejb access to ejbs in module1, they must be
packaged in the same .ear. Some implementations support local access across application
boundaries but that it not required and is not supported in the Java EE SDK.
The package hierarchy and any existence of an extra layer of service locator code is largely
irrelevant.All the matters is what component context is active at the time the calling code
is retrieving the ejb dependency.If all the client components are themselves EJBs, it's
easiest to just use @EJB in the bean class.If you want to do lookups of the ejb references
from other non-container managed classes, you'll need to define the ejb dependency for
each component in which the lookup can take place.
Here's an entry from our EJB FAQ on this topic :
https://glassfish.dev.java.net/javaee5/ejb/EJB_FAQ.html#POJOLocalEJB
