<resource-env-ref> cannot inject a SessionContext on p.198 of study guide

[Himai Minh]

On p. 197-198 of Ivan's notes, it says using <resource-env-ref> to inject a SessionContext, like this:

public class CommonStatelessSessionBean {
  
   protected SessionContext mSessionContext;
  ...
 protected void printSecurityInfo(){
	   if(mSessionContext != null){
		  Principal theCallerPrincipal = mSessionContext.getCallerPrincipal();
		  System.out.println(" Principal name: "+ theCallerPrincipal.getName());
		  System.out.println(" Principal object: "+ theCallerPrincipal);
		  System.out.println(" Principal type: "+ theCallerPrincipal.getClass());
		  testCallerRole("superusers");
		  testCallerRole("plainusers");
		  testCallerRole("ivan");
	   }
	   else{
		    System.out.println(" No session context available.");
	   }
   }
  

In ejb-jar.xml:

<resource-env-ref>
                   <resource-env-ref-name>java:comp/EJBContext</resource-env-ref-name>
                   <resource-env-ref-type>javax.ejb.EJBContext</resource-env-ref-type>
                   <injection-target>
                        <injection-target-class>com.ivan.scbcd6.CommonStatelessSessionBean</injection-target-class>
                        <injection-target-name>mSessionContext</injection-target-name>
                   </injection-target>
 </resource-env-ref>

The output is "No session context available".

I do this instead:

public class CommonStatelessSessionBean {
    ...
   @Resource(name="mySessionContext")
   protected SessionContext mSessionContext;
   
   ....

In my ejb-jar.xml ,

  <resource-env-ref>
                   <resource-env-ref-name>mySessionContext</resource-env-ref-name>
                   <resource-env-ref-type>javax.ejb.EJBContext</resource-env-ref-type>
                  <injection-target>
                        <injection-target-class>com.ivan.scbcd6.CommonStatelessSessionBean</injection-target-class>
                        <injection-target-name>mSessionContext</injection-target-name>
                   </injection-target>
               </resource-env-ref>

It works. It prints out the security information. It seems to me that I cannot remove @Resource for the SessionContext in CommonStatelessSessionBean.

[Frits Walraven]

I think the problem lies within the
<resource-env-ref-name>java:comp/EJBContext</resource-env-ref-name>
This is what the ejb-specs say:

16.8.1.3 Declaration of Resource Environment References in Deployment Descriptor
The resource-env-ref-name element specifies the resource environment reference name: its value is the environment entry name used in the enterprise bean code. The name of the environment entry is relative to the java:comp/env context.

I think your <resource-env-ref-name> should be:
<resource-env-ref-name>com.ivan.scbcd6.CommonStatelessSessionBean/mSessionContext</resource-env-ref-name>
I guess you should also change the <resource-env-ref-type> if you want to invoke specific methods on the SessionContext, into
<resource-env-ref-type>javax.ejb.SessionContext</resource-env-ref-type>

[Himai Minh]

Thanks for Frits's suggestion.
That is true.
I change the value in <resource-evn-ref> into the following and it works now. The notes needs to be updated.

<resource-env-ref>
                   <resource-env-ref-name>com.ivan.scbcd6.ejbs.CommonStatelessSessionBean/mSessionContext</resource-env-ref-name> 
                   <resource-env-ref-type>javax.ejb.SessionContext</resource-env-ref-type>
                   <injection-target>
                        <injection-target-class>com.ivan.scbcd6.ejbs.CommonStatelessSessionBean</injection-target-class>
                        <injection-target-name>mSessionContext</injection-target-name>
                   </injection-target>
               </resource-env-ref>

[Himai Minh]

I tried the deployment descriptor with security in Chapter 8 of Ivan's notes.
Let me correct my previous post.
Both approaches work. Ivan's deployment descriptor is fine and no need to be updated.

<session>
<ejb-name>StatelessSession1Bean</ejb-name>
<local-bean/>
<ejb-class>com.ivan.scbcd6.ejbs.StatelessSession1Bean</ejb-class>
<session-type>Stateless</session-type>
<ejb-local-ref>
<ejb-ref-name>StatelessSession2Bean</ejb-ref-name>
<ejb-ref-type>Session</ejb-ref-type>
...
</ejb-local-ref>
<resource-env-ref>
<resource-env-ref-name>java:comp/EJBContext</resource-env-ref-name>
<resource-env-ref-type>javax.ejb.EJBContext</resource-env-ref-type>
....
</resource-env-ref>

is the same as

<session>
<ejb-name>StatelessSession1Bean</ejb-name>
<local-bean/>
<ejb-class>com.ivan.scbcd6.ejbs.StatelessSession1Bean</ejb-class>
<session-type>Stateless</session-type>
<ejb-local-ref>
<ejb-ref-name>StatelessSession2Bean</ejb-ref-name>
<ejb-ref-type>Session</ejb-ref-type>
...
</ejb-local-ref>
<resource-env-ref>
<resource-env-ref-name>com.ivan.scbcd6.ejbs.CommonStatelessSessionBean/mSessionContext</resource-env-ref-name>
<resource-env-ref-type>javax.ejb.EJBContext</resource-env-ref-type>
....
</resource-env-ref>

[Frits Walraven]

Thanks for the update!