How to call an EJB from another EJB

Question

Hi
I have a problem here. I need to execute a second EJB which has to get the input from the first EJB as data for execution. So when I call the first EJB, the first EJB should give the data to the second EJB and execute it and provide the result.
Cheers,
Raj

Answer 1

ok.. Here it goes.. I am writing a sample code..
public class EJB1LogBean implements SessionBean {
// test is a method of stateless session beam
public void test ( TestVal val )
throws RemoteException{
try {
EJB2LogHome ejb2Home= (EJB2LogHome)getHome("java:comp/env/ejb/EJB2LogHome",1);
EJB2Log ejb2Log = ejb2LogHome.create ( val );
} catch ( CreateException e ) {
     System.out.println("Create Exception occurred ");
     e.printStackTrace();
     } catch ( RemoteException e ) {
     System.out.println( "RemoteException Occured");
e.printStackTrace();
     throw new RemoteException () ;
     } catch(Exception ee) {
ee.printStackTrace();
private EJBHome getHome(String jndiName,int type) {
try {
Context context = new InitialContext();
Object ref = context.lookup( jndiName );
switch(type)
case 1:
EJB2LogHome ejb2LogHome = ( EJB2LogHome )
PortableRemoteObject.narrow( ref, EJB2LogHome.class );
return ejb2LogHome;
} catch ( Exception e ) {
e.printStackTrace();
return null;
}//EJB1LogBean ends
Here as you can see, EJB1LogBean(session bean) is calling a second EJB, EJB2LogBean (entity bean). TestVal is a sample value object passed. It is plain java class and can vary from app to app and it has got nothing to do with ejbs.
"java:comp/env/ejb" is a J2EE standard and while getting a home interface, you have to append the home interface class name to "java:comp/env/ejb". Here I am passing "java:comp/env/ejb/EJB2LogHome" and "1" to getHome method, whose job is to get a reference to a home interface. getHome method is a local method. "1" is passed just to give a flexibility to getHome method as you can have more ejbs to invoked. In that case, you can go on adding different case statements for 2, 3 etc.
The only thing you have to keep in mind is that your deployment descriptor for EJB1LogBean will contain the entires for both the beans i.e. for EJB1LogBean and EJB2LogBean. This is because EJB2LogBean is wrapped by EJB1LogBean.
Hope this helps.
Please let me know if you need anything more.
- Amit