Weblogic7/examples/clustering/ejb Automatic failover for idempotent methods ?

Question

This one should be easy since it is from the examples folder of bea 7 about
          clustering.
          Ref : \bea7\weblogic007\samples\server\src\examples\cluster\ejb
          I am referring to the cluster example provided with the weblogic server 7.0
          on windows 2000.
          I deployed Admin server and 2 managed server as described in document.
          Everything works fine as shown by the example. I get load balancing and
          failover both. Too Good.
          Client.java is using the while loop to manage the failover. So on exception
          it will go thru the loop again.
          I understand from the documentation that the stateless session EJB will
          provide the automatic failover for Idempotent stateless bean
          Case Failover Idempotent : ( Automatic )
          If methods are written in such a way that repeated calls to the same method
          do not cause duplicate updates, the method is said to be "idempotent." For
          idempotent methods, WebLogic Server provides the
          stateless-bean-methods-are-idempotent deployment property. If you set this
          property to "true" in weblogic-ejb-jar.xml, WebLogic Server assumes that the
          method is idempotent and will provide failover services for the EJB method,
          even if a failure occurs during a method call.
          Now I made 2 changes to the code.
          1 . I added as follows to the weblogic-ejb-jar.xml of teller stateless EJB
          <stateless-clustering>
          <stateless-bean-is-clusterable>true</stateless-bean-is-clusterable>
          <stateless-bean-load-algorithm>random</stateless-bean-load-algorithm>
          <stateless-bean-methods-are-idempotent>true</stateless-bean-methods-are-idem
          potent>
          </stateless-clustering>
          So I should get the automatic failover .............
          2. Also I added the break statement in the catch on line around 230 in
          Client .java
          catch (RemoteException re) {
          System.out.println(" Error: " + re);
          // Replace teller, in case that's the problem
          teller = null;
          invoke = false;
          break;
          So that the client program does not loop again and again.
          Now I compile and restart all my three servers and redeploy application (
          just to be sure )
          I start my client and I get a automatic load balancing between the server
          which makes me happy.
          But Failover ....?
          I kill one of the managed application server in cluster at any particular
          test fail point.
          I expect the exception to be taken care automatically by error/failover
          handler in the home/remote stub
          But the client program fails and terminates.
          1. What is wrong with the code ?
          2. Does the automatic failover with the indempotent methods also has to be
          taken care by coding the similar while loop for stateless ejb ?
          Your help will be appreciated ASAP.
          Let me know if you need any thing more from my system. But I am sure this
          will be very easy as it is from the sample code.........
          Thanks
          

Answer 1

Sorry I meant to send this to the ejb newsgroup.
          dan
          dan benanav wrote:
          > Do any vendors provide for clustering with automatic failover of entity
          > beans? I know that WLS does not. How about Gemstone? If not is there
          > a reason why it is not possible?
          >
          > It seems to me that EJB servers should be capable of automatic failover
          > of entity beans.
          >
          > dan