Handling disconnections in stateful beans

i have a stateful bean with some resources that it has to close after closing. I programed a close () method, marked as +@Remove+, that clients call to close the resources; and a exiting () method, marked as @PreDestroy to finish the work.
but, how can i handle unexpected disconnections, for clients frozen, cable network disconnected or the like, when the client () can't call the close method?
It thought that +@PreDestroy+ method should replace finalize method's, but it doesn't.
What can i do?

Ok... Here it goes...
You can do it in the following manner.
As you said you have got 2 private methods doing d/b updates and these are called from a public method.
Stateful session beans since associated with a client across methods, you can take advantage of it. Write your own user defined transaction.
Begin the transaction scope in your public before calling the 1st private method. Call the 2 methods in a try block. Once you are done with these methods, you can commit and end the transaction. If you get any exception, rollback the transaction in the catch block. Otherwise if u get any exception in the 2nd method, you can rollback the transaction there itself.
Stateful session beans lets u allow to spawn the bean managed transaction across methods. you can begin your transaction in one method and end it in a differnt method or you can end the transaction after calling the methods.
The problem you are dealing with can typically very well handled by writing bean managed transaction.
Hope this helps. If you need anymore clarity on my solution, please let me know.
-amit

Similar Messages

Stateful bean handle in HttpSession

          Hi ,
          I have environment where i create a pool of stateful EJB's and I store the pool
          in the servlet context. For each requests I obtain the refernce to the ejbhandle
          from the pool and exceute the method on the stateful bean. I use this ejbhandle till
          the session is ended. Is there any problem with this sort of design in the clustering
          environment?
          As per the httpsession replication after the state of the object stored in the sesion
          is changed , setAttribute method has to be called for the replication. So is it the
          same for ejbhandle also?
          After I call some methos on the SFEJB (getting a reference via EJBHandle in the session),
          do I have to call set sttaribute and pass the ejb handle for the replication?
          Any amount of feed back is appreciated.
          Thanks,
          sri


The handle is serializable and portable. You can put it into the HTTP
          session. If you don't use setAttribute, the data won't get replicated. For
          example:
          Object[] ao = new Object[10];
          session.putAttribute("test", ao);
          // replication occurs
          ... later ...
          Object[] ao = (Object[]) session.getAttribute("test");
          ao[3]="hello world";
          // no replication occurs
          Peace,
          Cameron Purdy
          Tangosol, Inc.
          http://www.tangosol.com/coherence.jsp
          Tangosol Coherence: Clustered Replicated Cache for Weblogic
          "sri" <[email protected]> wrote in message
          news:[email protected]...
          >
          > Hi ,
          >
          > I have environment where i create a pool of stateful EJB's and I store
          the pool
          > in the servlet context. For each requests I obtain the refernce to the
          ejbhandle
          > from the pool and exceute the method on the stateful bean. I use this
          ejbhandle till
          > the session is ended. Is there any problem with this sort of design in
          the clustering
          > environment?
          >
          > As per the httpsession replication after the state of the object stored in
          the sesion
          > is changed , setAttribute method has to be called for the replication. So
          is it the
          > same for ejbhandle also?
          > After I call some methos on the SFEJB (getting a reference via EJBHandle
          in the session),
          > do I have to call set sttaribute and pass the ejb handle for the
          replication?
          >
          > Any amount of feed back is appreciated.
          >
          > Thanks,
          > sri
          >

Stateful bean and cursor

Is a stateful bean maintaining a reference to a ResultSet an acceptable design?
The concern is that the resultset might need to be closed after each Stateful
Bean access such that we don't hold on resources on the database.
Stefan

Thanks Bob,
That's exactly what I was asking and it seems more clear now. Interesting if multiple
ResultsSet kept around open could share same db connection in which case this
could somehow scale. My concern was more directed towards number of Open Cursors
in the database, but overall it does not look like a proper design ...
Stefan
"Bob Lee" <[email protected]> wrote:
Not if the ResultSet will be kept open accross multiple web requests.
The
result set is most likely tied to a database connection. If too many
are
kept open, you database connection pool will get maxed out, and other
users
won't be able to access the site.
You can handle the paging by running the query every time. You can also
keep
an index of the column you are sorting on and use this to pick out exact
pages in your query. Memory is cheap.
Bob
"Stefan" <[email protected]> wrote in message
news:3c7be741$[email protected]..
Is a stateful bean maintaining a reference to a ResultSet an acceptabledesign?
The concern is that the resultset might need to be closed after eachStateful
Bean access such that we don't hold on resources on the database.
Stefan

How to get handle to a MST bean for a particular row in an advanced table

Hi
Requirement:
My advanced table has 2 columns, the 1st one has a LOV and the 2nd one is a switcher which toggles from LOV to MST depending on the value in the 1st column.
Implementation Steps:
1) Trap LOV event in 1st column and pass row index to the AM
2) Get the VO row from the row index (EVENT_SOURCE_ROW_REFERENCE), set the switcher attribute to MST/LOV depending on Business Logic
3) Get the view attribute value of the 2nd column (to which LOV/MST is mapped).
My LOV/MST gets rendered correctly on the page. However, when the LOV renders in the 2nd column, the view attribute is correctly populated in the LOV. But the MST renders with no value.
I understand that the MST loses value on form submission and that this value needs to be set in the PR of the CO. For that how do I get a handle to the MST bean of the particular row?
This is urgent!!
Thanks
Ritu

Pointers?
Anyway I can make the MST in the row return the correct view attribute?

EJB 3.0 Stateful bean not saving state while Stateless bean is !!!

My Stateless bean is as follow:
package test;
import javax.ejb.Stateless;
@Stateless(mappedName = "StatelessBean")
public class StatelessBean implements StatelessBeanRemote {
     int counter;
     public void increment(){
          System.out.println("Stateless counter value:"+counter);
          counter++;
My Stateful bean is as follow:
package test;
import javax.ejb.Stateful;
@Stateful(mappedName = "StateFulBean")
public class StateFulBean implements StateFulBeanRemote {
     int counter;
     public void increment(){
          System.out.println("Stateful counter value:"+counter);
Client is as follows:
package test;
import java.util.Hashtable;
import javax.naming.Context;
import javax.naming.InitialContext;
public class TestClient {
     public static void main(String[] args) {
          Hashtable hashtable = new Hashtable();
          hashtable.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
          hashtable.put(Context.PROVIDER_URL, "t3://localhost:7001");
          InitialContext ic;
          try {
               ic = new InitialContext(hashtable);
               StateFulBeanRemote stateFulBeanRemote = (StateFulBeanRemote)ic.lookup("StateFulBean#test.StateFulBeanRemote");
               stateFulBeanRemote.increment();
               StatelessBeanRemote statelessBeanRemote = (StatelessBeanRemote)ic.lookup("StatelessBean#test.StatelessBeanRemote");
               statelessBeanRemote.increment();
          } catch (Exception e) {
               e.printStackTrace();
The output i am getting after running the client twice is as follows:
//first time
Stateful counter value:0
Stateless counter value:0
//second time
Stateful counter value:0
Stateless counter value:1
Shouldn't the counter values be incremented in case of Stateful bean and remain the same for Stateless bean. But the output that I am getting is the complete opposite !!!
Can anyone please explain this confusing behavior of stateless and stateful ejb 3.0 beans.

868664 wrote:
Can anyone please explain this confusing behavior of stateless and stateful ejb 3.0 beans.It is very simple: a stateless bean is ASSUMED to be stateless; you cannot keep state in a stateless bean as a contractual rule. That doesn't mean that you will fail to keep state in them at least for a little while, they are still only Java objects. Generally stateless EJBs are pooled, so you may get the same instance each time you use such an EJB, but you may just get another one. It is not dependable and the rules say don't do it - so don't do it.
A stateful bean is tied to a single client, and so can be used by a client to keep state in it. Since You are running the client application twice you are operating with two different clients and so you will get a new stateful bean each time and your code will keep printing 0. However there is also a bug in your code:
public void increment(){
System.out.println("Stateful counter value:"+counter);
}You are not incrementing anything.

Help me in Stateless & Stateful Bean

hi,
I'm trying to understand to difference between the stateless and stateful bean. I had created an simple application to test it. But both the beans seems to work in the same way. Could some one explain me with an example the difference between the stateful and stateless bean ...
I'm using J2EE Reference Implementation and Deploytool .
Please help me .. Urgent ....
Cheers !!!
Prabs

Thanks!!
The State Session Bean tries to hold data , even after the client has finished execution. Moreover, the ejbCreate() get fired only once and not for different client.
Is there anything that I should do to make it stateless.
this is my code
Session Bean
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;
import java.util.*;
public class cartEJB implements SessionBean {
     private Map m;
     public cartEJB() { }
     public void ejbCreate() {
     m = new HashMap();
     System.out.println("ejbCreate()");
     public void ejbActivate() { }
     public void ejbPassivate() { }
     public void ejbRemove() { }
     public void setSessionContext(SessionContext sc) { }
     public void addCart(String product, String price) {
     System.out.println("Its here Man 1");
     m.put(product, price);
     public void showCart() {
          System.out.println("Its here Man 2");
          Set s = m.entrySet();
          Iterator it = s.iterator();
          while(it.hasNext()) {
               System.out.println(it.next());
REMOTE
import javax.ejb.EJBObject;
import java.rmi.RemoteException;
public interface cart extends EJBObject {
     public void addCart(String product , String price) throws RemoteException;
     public void showCart() throws RemoteException;
HOME
import javax.ejb.EJBHome;
import java.rmi.RemoteException;
import javax.ejb.CreateException;
public interface cartHome extends EJBHome {
     public cart create() throws CreateException, RemoteException;
client application is an web based application ..
Client code. ... (jsp:useBean)
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.rmi.PortableRemoteObject;
import javax.servlet.http.*;
public class cartJSP implements HttpSessionBindingListener{
     String Product = new String();
     String Price = new String();
     HttpSession session;
     public cartJSP() {
     public void setProduct(String p){
          this.Product = p;
     public void setPrice(String price) {
          this.Price=price;
     public String getPrice() {
          return Price;
     public String getProduct() {
          return Product;
     public void addIt(String product , String price ) {
     try {
          System.out.println("Comes here");
          Context ic = new InitialContext();
          Object objref = (Object)ic.lookup("ejb/cartJNDI");
          cartHome home = (cartHome)PortableRemoteObject.narrow(objref, cartHome.class);
          cart remote = home.create();
          remote.addCart(product, price);
          System.out.println("Comes here");
          remote.showCart();
     catch(Exception e) {
          e.printStackTrace();
     public void showIt() {
     try {
          Context ic = new InitialContext();
          Object objref = (Object)ic.lookup("ejb/cartJNDI");
          cartHome home = (cartHome)PortableRemoteObject.narrow(objref, cartHome.class);
          cart remote = home.create();
          remote.showCart();
          System.out.println("Comes here 1");
     catch(Exception e) {
          e.printStackTrace();
     public void valueBound(HttpSessionBindingEvent e) {
          session = e.getSession();
          session.setMaxInactiveInterval(60);
          System.out.println("Value Bound");
     public void valueUnbound(HttpSessionBindingEvent e) {
          System.out.println("Value UnBound");
I'm using J2EE RI 1.3 and I'm deploying components using deploytool.
Please help me,
Check the code is wrong or is it a bug in the EJB container.
regards
prabu.

Stateful bean not failing over

          I have a cluster of two servers and a Admin server. Both servers are running NT
          4 sp6 and WLS6 sp1.
          When I stop one of the servers, the client does n't automatically failover to
          the other server, instead it fails unable to contact server that has failed.
          My bean is configured to have its home clusterable and is a stateful bean. My
          client holds onto the remote interface, and makes calls through this. If Server
          B fails then it should automatically fail over to server A.
          I have tested my multicast address and all seems to be working fine between servers,
          my stateless bean work well, load balancing between servers nicely.
          Does anybody have any ideas, regarding what could be causing the stateful bean
          remote interface not to be providing failover info.
          Also is it true that you can have only one JMS destination queue/topic per cluster..The
          JMS cluster targeting doesn't work at the moment, so you need to deploy to individual
          servers?
          Thanks


Did you enable stateful session bean replication in the
          weblogic-ejb-jar.xml?
          -- Rob
          Wayne Highland wrote:
          >
          > I have a cluster of two servers and a Admin server. Both servers are running NT
          > 4 sp6 and WLS6 sp1.
          > When I stop one of the servers, the client does n't automatically failover to
          > the other server, instead it fails unable to contact server that has failed.
          >
          > My bean is configured to have its home clusterable and is a stateful bean. My
          > client holds onto the remote interface, and makes calls through this. If Server
          > B fails then it should automatically fail over to server A.
          >
          > I have tested my multicast address and all seems to be working fine between servers,
          > my stateless bean work well, load balancing between servers nicely.
          >
          > Does anybody have any ideas, regarding what could be causing the stateful bean
          > remote interface not to be providing failover info.
          >
          > Also is it true that you can have only one JMS destination queue/topic per cluster..The
          > JMS cluster targeting doesn't work at the moment, so you need to deploy to individual
          > servers?
          >
          > Thanks
          Coming Soon: Building J2EE Applications & BEA WebLogic Server
          by Michael Girdley, Rob Woollen, and Sandra Emerson
          http://learnweblogic.com

Problem with Maintaining State with EJB3 Stateful Bean

I'm a newbie in EJB3. I've wrote a Stateful bean together with JSF as the UI tier. Below is my Stateful bean.
package com.dhydrated.business;
import com.dhydrated.entity.User;
import java.io.Serializable;
import javax.ejb.Remove;
import javax.ejb.Stateful;
@Stateful
public class LogonBean
        implements LogonRemote, Serializable {
    private User user;
    public void setUser(User user) {
        this.user = user;
    public User getUser() {
        return user;
}In above code, I'm storing User object as the private variable. The problem is, whenever I set the User object in the 1st page, I'm unable to retrieve the same user object in the 2nd page. Seems like my Stateful bean does not saved the state or conversation of the bean.
Appreciate if someone could tell me on how to save the state of above Stateful bean. Is there some other conf. that I might missed out?

I was find good solution! =)
*** JScript ***
<script TYPE="text/javascript">

</script>
*** JSF ***
<h:form onsubmit="popup(this)">
<h:commandButton value="Press Me" actionListener="#{sessionBean.resetCursor}" action="selectElemList" />
</h:form>
But it work only with <h:commandButton> tag. If you try to use <h:commandLink>, then 'onsubmit' attribute by <form> tag don't work.
If you know how make necessary functional with <h:commandLink> tag, please let me know.

Stateful beans in cache doesn't seem to work

I have a stateful bean that I have set max beans in cache to "1". When I deploy it, no errors reported or so, the Weblogic console still states "8" in the column "Cached Beans Current Count" when monitoring the bean.
When I view the descriptor in the console it looks fine. What can be wrong here?
Using Weblogic 8.1 SP4, here's the statueful descriptor:
<weblogic-enterprise-bean>
<ejb-name>MyStatefulBean</ejb-name>
<stateful-session-descriptor>
<stateful-session-cache>
<max-beans-in-cache>1</max-beans-in-cache>
</stateful-session-cache>
<allow-concurrent-calls>True</allow-concurrent-calls>
</stateful-session-descriptor>
<reference-descriptor>
</reference-descriptor>
<enable-call-by-reference>True</enable-call-by-reference>
<jndi-name>test.mystatefulbean/MyStatefulBean/Home</jndi-name>
<local-jndi-name>test.mystatefulbean/MyStatefulBean/LocalHome</local-jndi-name>
</weblogic-enterprise-bean>

I agree with you about the host not being able to install (or at least don't want to install/upgrade) their servers to php5.4... Unfortunately, I can't change that... but by shutting them off took care of all the quotes (single & double) and any other characters which would basically function like an addslashes() command. I'll paste the script below... It's still pretty much the same as when you helped me out with the script... Just minor adjustments::: If you can show me (even though I fixed the problem) how I would integrate the stripslashes() function to the comment field it would be helpful to know for future reference.
<?php // Script 1.0 - contactlist.php
if (isset($_POST['submit']) && !empty($_POST['submit'])) // Test if submit button named submit was clicked and not empty
          if (!empty($_POST['first']) && !empty($_POST['last']) && !empty($_POST['email']) && !empty($_POST['phone']) && !empty($_POST['comment'])) {
$comment=stripslashes($_POST[comment]);
                    $body = "First Name: {$_POST['first']}\nLast Name: {$_POST['last']}\nEmail Address: {$_POST['email']}\nContact Phone Number: {$_POST['phone']}\nContact Preference: {$_POST['contactvia']}\n\nBest Time To Contact: {$_POST['timepref']}\n\nComments:\n {$_POST['comment']}";
                    $body = wordwrap($body, 70);
                    mail([email protected]', 'NEW Customer Inquiry Submission',$body, "From: {$_POST['email']}");
                    header('Location: index.html'); //Redirect to new url if form submitted
?>

Stateful bean clustering

Hi,
          Does weblogic 5.1 support stateful bean clustering? If not how to achive this?
          Thanks in advance,
          vivek


6.x supports stateful session beans clustering (replication and failover), but not 5.1.
          Vivek <[email protected]> wrote:
          > Hi,
          > Does weblogic 5.1 support stateful bean clustering? If not how to achive this?
          > Thanks in advance,
          > vivek
          Dimitri

Stateless and Stateful beans.

Please tell me what are the important differences between stateless, and stateful beans.
Thanks in advance.

See this thread
http://forum.java.sun.com/thread.jsp?forum=13&thread=529706&tstart=15&trange=15

Handling Transaction in Stateful Session Bean

I wrote a public method like public void doTransaction()
it will call 2 private method, like: methodA and methodB
Both private methods have db accesss statement and will update the db. They got different db connection and will close the connection when method call finished.
How to include them to one transaction? I want to be able to rollback the job of the first method when I catch exception thrown by the second method.
I tried simply define transaction type of the public method to be Container and Required. But it doesn't work, the first method doesn't rollback. Of course I can let the 2 private methods share a same connection and commit after finishing calling them. But how if they are in different DB?

Ok... Here it goes...
You can do it in the following manner.
As you said you have got 2 private methods doing d/b updates and these are called from a public method.
Stateful session beans since associated with a client across methods, you can take advantage of it. Write your own user defined transaction.
Begin the transaction scope in your public before calling the 1st private method. Call the 2 methods in a try block. Once you are done with these methods, you can commit and end the transaction. If you get any exception, rollback the transaction in the catch block. Otherwise if u get any exception in the 2nd method, you can rollback the transaction there itself.
Stateful session beans lets u allow to spawn the bean managed transaction across methods. you can begin your transaction in one method and end it in a differnt method or you can end the transaction after calling the methods.
The problem you are dealing with can typically very well handled by writing bean managed transaction.
Hope this helps. If you need anymore clarity on my solution, please let me know.
-amit

Handling BLOBs with CMP Beans

Hi,
is there a detailed example how to handle Blob's with CMP Beans?
I'm trying to store some images in a database (Oracle 9i) using CMP Beans and Oracle iAS 9.03 and jdk 1.4.
Thanks in advance
Jens

We are currently developing a How-To on this and will put this on OTN.
1) Code snippet from Bean Class:
public abstract byte[] getPicture();
public abstract void setPicture(byte[] newPicture);
public Long ejbCreate(Long empno, byte[] newPicture)
setEmpno(empno);
setPicture(newPicture);
return empno;
public void ejbPostCreate(Long empno, byte[] newPicture)
2) Mapping in the orion-ejb-jar.xml:
<entity-deployment name="EmployeePicture" data-source="jdbc/OracleDS" table="EMPPIC">
<primkey-mapping>
<cmp-field-mapping name="empno" persistence-name="EMPNO" persistence-type="NUMBER(8)"/>
</primkey-mapping>
<cmp-field-mapping name="empno" persistence-name="EMPNO" persistence-type="NUMBER(8)"/>
<cmp-field-mapping name="picture" persistence-name="PICTURE" persistence-type="BLOB(4000)"/>
</entity-deployment>
3) Create the client to create the bean:
Long empNo =(Long) Long.valueOf(request.getParameter("EmpNo"));
String fileName =request.getParameter("ImageFileName");
InputStream is = new BufferedInputStream(new FileInputStream(fileName));
int len;
// Initialize byte array
byte byteValue[] = new byte[2048000];
len = is.read(byteValue);
EmployeePictureLocal employeePicture = empHome.create(empNo , byteValue);
out.println("Picture of Emp#:"+empNo +" successfully Loaded into DB <br> <br>");
4) Code snippet to view the image :
Long empNo =(Long) Long.valueOf(request.getParameter("EmpNo"));
out.println("Picture of Emp#"+empNo);
EmployeePictureLocal emp = empHome.findByPrimaryKey(empNo);
response.setContentType("image/jpeg");
OutputStream os = null;
os = response.getOutputStream() ;
byte[] pic = emp.getPicture();
os.write(pic);
os.close();
os = null;
Let me know if this helps
thanks
Debu

WL 7.0 Fault-tolerant stateful beans. (Newbie)

Hello,
I was wondering if in WL 7.0 there is a way to make a stateful session
bean automatically persist its state without having to be passivated
as a whole.
The bean that I need to build would persist its state to a DB each
time a remote method call is executed in it. The purpose is to make
this bean fault tolerant without having to serialize the whole object
graph by using passivation.
I heard that WL 7.0 has a new feature that can make this happen but I
can't seem to find any info on this. Could anyone point me into the
right search path?
Thanks in advance.
Mateo.

I'm not aware of such feature in WLS 7.0 EJB container.
Where did you heard about it? If at all there's a feature you should
be able to locate at our online docs.
Here's the link
http://e-docs.bea.com/wls/docs70/ejb/index.html
Kumar
Mateo wrote:
Hello,
I was wondering if in WL 7.0 there is a way to make a stateful session
bean automatically persist its state without having to be passivated
as a whole.
The bean that I need to build would persist its state to a DB each
time a remote method call is executed in it. The purpose is to make
this bean fault tolerant without having to serialize the whole object
graph by using passivation.
I heard that WL 7.0 has a new feature that can make this happen but I
can't seem to find any info on this. Could anyone point me into the
right search path?
Thanks in advance.
Mateo.

Contextual event - handler called before producer bean's setter

I am trying a simple contextual events usecase:
Page A.jsff has an input text field whose value is directly stored in a bean variable (bean is in pageFlowScope). Contextual event is defined on value change event for this input field. A.jsff has taskflow B_btf as an embedded region.This B_btf will simply display the value entered in the A.jsff. So, when contextual event is raised, the handler sets the value in a local variable of B_btf bean. The problem is that the handler method is getting called before the setter for the attribute of the bean of A.jsff. This is resulting in the B_btf displaying the last-but-one value entered in the input field of A.jsff instead of the current/latest value. Any tips?
Thanks,
Amitabh

The issue was with the (lack of) understanding of the JSF lifecycle. The value change listener is called during the Process Validation phase, whereas the managed bean (Model) values will be set in the Update Model phase which lies next-in-line after Process Validation phase. Hence, if the value change listener is to be used, then the handler code should have used the default payload and not the custom payload. For a value change event the default payLoad will be a DCBindingContainerValueChangeEvent, and one can invoke getNewValue() to get the value entered in the text field (For details watch Frank Nimphius' video here: ADF Region Interaction - Contextual Events - YouTube). For my case, I added a command button to the page, and moved the contextual event to that button.

Handling disconnections in stateful beans

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