Entity Beans /JDO and Datawarehousing

Hi,
Currently i'm involved in a project, in which we want to generate some very basic custom reports, like turnover calculations etc.
These reports will be publish on a intranet environment.
My questions are:
How do Entity Beans perform when handling large tables (like a few million of rows).
What about transactions? The datawarehouse will not be updated by the application. Is it therefore advisible to turn it of, in order to gain performance?
I'm am completely new to JDO, would JDO be a better alternative compared to entity beans when working with large resultsets?
I hope someone can help
Thanks and Regards,
Velli

hello
I strongly suggest to use JDBC instead of EJB/JDO. EJB's are great if you need transactions and has a lot of concurrent access. But they are very slow if you read huge data, because for every row an EJB instance is created. For reports you would need to iterate all those instance, in short, performace would be very bad.
Turning off transactions wont help. Some containers (WEBLogic) allows to configure entity beans as "read only", thus improving performance by data caching in EJB instances. So... if you really need EJB then you can use that.
However this would not be very effective too, if you really have millions of rows, because it's not possible to keep them all in RAM.
For several thousands of records it would be very good, but not millions.
Furthermore, several design patterns suggest to use JDBC in such sitoation. For more information you can read:
+ http://java.sun.com/blueprints/patterns/FastLaneReader.html
+ book "EJB design patterns" (You can find it at TSS)
+ book "Bitter Java"
Maris Orbidans
System.out.println(out2.readOutputValue());

Similar Messages

BMT Entity Bean creation and Weblogic Workshop 8.1

I've looked everywhere I could to find information and an example on how to create a BMP entity bean using Workshop 8.1. Can someone please point me to an example or instructions on how to create this bean? I know how to do it outside of workshop, but there appears to be no option in workshop to specify that my entity bean is BMP and not CMP.
Thanks,
Daryl

Hi Simon,
Are you referring to a 8.1 JWS Web Service ? If yes, unfortunately you cannot deploy this to WLS 9.1. You will need to wait for the 9.2 release and upgrade the web service to use the new JSR-181 annotations and then deploy. The upgrade tool will however take care of all the details associated with the upgrade.
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Problem with 1-to-many relationship between entity beans

Hi All!
I have two tables TMP_GROUP and TMP_EMPLOYEE with following fields:
TMP_GROUP: ID, CAPTION, COMMENT, STATUS.
TMP_EMPLOYEE: ID, LOGIN, GROUP_ID.
For this tables i create two entity beans GROUP and EMPLOYEE respectively.
The relationship looks like this
descriptor ejb.xml:
<ejb-relation>
            <description>description</description>
            <ejb-relation-name>employeesOfGroup</ejb-relation-name>
            <ejb-relationship-role>
                <ejb-relationship-role-name>com.mypackage.GroupBean</ejb-relationship-role-name>
                <multiplicity>One</multiplicity>
                <relationship-role-source>
                    <ejb-name>GroupBean</ejb-name>
                </relationship-role-source>
                <cmr-field>
                    <cmr-field-name>employees</cmr-field-name>
                    <cmr-field-type>java.util.Collection</cmr-field-type>
                </cmr-field>
            </ejb-relationship-role>
            <ejb-relationship-role>
                <ejb-relationship-role-name>com.mypackage.EmployeeBean</ejb-relationship-role-name>
                <multiplicity>Many</multiplicity>
                <relationship-role-source>
                    <ejb-name>EmployeeBean</ejb-name>
                </relationship-role-source>
            </ejb-relationship-role>
        </ejb-relation>
descriptor persistent.xml:
<table-relation>
               <table-relationship-role
                    key-type="PrimaryKey">
                    <ejb-name>GroupBean</ejb-name>
                    <cmr-field>employees</cmr-field>
               </table-relationship-role>
               <table-relationship-role
                    key-type="NoKey">
                    <ejb-name>EmployeeBean</ejb-name>
                    <fk-column>
                         <column-name>GROUP_ID</column-name>
                         <pk-field-name>ejb_pk</pk-field-name>
                    </fk-column>
               </table-relationship-role>
          </table-relation>
Now i implement business method:
public Long addEmployee(String login, long groupId) {
          Long result;
          try {
               EmployeeLocal employee = employeeHome.create(login);
               GroupLocal group =
                    groupHome.findByPrimaryKey(new Long(groupId));
               Collection employees = group.getEmployees();
               employees.add(employee);
               result = (Long) employee.getPrimaryKey();
          } catch (CreateException ex) {
               result = new Long(0);
          } catch (FinderException ex) {
               result = new Long(0);
          return result;
When i call this method from web service, the following exception is raised:
com.sap.engine.services.ejb.exceptions.BaseTransactionRolledbackLocalException: Exception in method com.mypackage.GroupLocalHomeImpl0.findByPrimaryKey(java.lang.Object).
P.S.
1) I have transaction attribute set to "Required" for all methods of all beans
2) I have unique index for each table:
TMP_GROUP_I1: CAPTION
TMP_EMPLOYEE_I1: LOGIN (however i think GROUP_ID must be added here too)
3) I tried many:many relationship with this tables and it works fine
4) I try another implementation of addEmployee method with
EmployeeLocal employee = employeeHome.create(login, groupId);
without using GroupLocal cmr-field and GroupLocalHome findByPrimaryKey method, the result is same error.
Can somebody help me with this problem?
Thanks in advance.
Best regards, Abramov Andrey.

gimbal2 wrote:
1: The @JoinColumn on the listOfDepartments collection in Company is wrong. It should be something like this for a bidirectional relationship:
@OneToMany(mappedBy="company") // company is the matching property name in Department
private List <Department> listOfDepartment = new ArrayList<Department>();Note that I removed the fetch configuration; onetomany is fetched lazy by design. Saves some clutter eh.
2: use a Set in stead of a List (hibernate doesn't like lists much in entities and will break when you create slightly more complex entity relations)
3: don't just slap cascades on collections, especially of type ALL. Do it with care. In the many years I've been using JPA I've only had to cascade deletes in very specific situations, maybe once or twice. I never needed any of the other cascade types, they just invite sloppy code if you ask me. When working with persistence you should apply a little precision.I made all changes as you mentioned but still compID in department table shows null value...

Problem with 1:many relationship between entity beans.

Hi All!
I have two tables TMP_GROUP and TMP_EMPLOYEE with following fields:
TMP_GROUP: ID, CAPTION, COMMENT, STATUS.
TMP_EMPLOYEE: ID, LOGIN, GROUP_ID.
For this tables i create two entity beans GROUP and EMPLOYEE respectively.
The relationship looks like this
descriptor ejb.xml:
<ejb-relation>
            <description>description</description>
            <ejb-relation-name>employeesOfGroup</ejb-relation-name>
            <ejb-relationship-role>
                <ejb-relationship-role-name>com.mypackage.GroupBean</ejb-relationship-role-name>
                <multiplicity>One</multiplicity>
                <relationship-role-source>
                    <ejb-name>GroupBean</ejb-name>
                </relationship-role-source>
                <cmr-field>
                    <cmr-field-name>employees</cmr-field-name>
                    <cmr-field-type>java.util.Collection</cmr-field-type>
                </cmr-field>
            </ejb-relationship-role>
            <ejb-relationship-role>
                <ejb-relationship-role-name>com.mypackage.EmployeeBean</ejb-relationship-role-name>
                <multiplicity>Many</multiplicity>
                <relationship-role-source>
                    <ejb-name>EmployeeBean</ejb-name>
                </relationship-role-source>
            </ejb-relationship-role>
        </ejb-relation>
descriptor persistent.xml:
<table-relation>
               <table-relationship-role
                    key-type="PrimaryKey">
                    <ejb-name>GroupBean</ejb-name>
                    <cmr-field>employees</cmr-field>
               </table-relationship-role>
               <table-relationship-role
                    key-type="NoKey">
                    <ejb-name>EmployeeBean</ejb-name>
                    <fk-column>
                         <column-name>GROUP_ID</column-name>
                         <pk-field-name>ejb_pk</pk-field-name>
                    </fk-column>
               </table-relationship-role>
          </table-relation>
Now i implement business method:
public Long addEmployee(String login, long groupId) {
          Long result;
          try {
               EmployeeLocal employee = employeeHome.create(login);
               GroupLocal group =
                    groupHome.findByPrimaryKey(new Long(groupId));
               Collection employees = group.getEmployees();
               employees.add(employee);
               result = (Long) employee.getPrimaryKey();
          } catch (CreateException ex) {
               result = new Long(0);
          } catch (FinderException ex) {
               result = new Long(0);
          return result;
When i call this method from web service, the following exception is raised:
com.sap.engine.services.ejb.exceptions.BaseTransactionRolledbackLocalException: Exception in method com.mypackage.GroupLocalHomeImpl0.findByPrimaryKey(java.lang.Object).
P.S.
1) I have transaction attribute set to "Required" for all methods of all beans
2) I have unique index for each table:
TMP_GROUP_I1: CAPTION
TMP_EMPLOYEE_I1: LOGIN (however i think GROUP_ID must be added here too)
3) I tried many:many relationship with this tables and it works fine
4) I try another implementation of addEmployee method with
EmployeeLocal employee = employeeHome.create(login, groupId);
without using GroupLocal cmr-field and GroupLocalHome findByPrimaryKey method, the result is same error.
Can somebody help me with this problem?
Thanks in advance.
Best regards, Abramov Andrey.

I have posted excerpts from my orion-ejb-jar.xml file in this posting: Problem mapping a 1:M relationship between two entity EJBs w/ a compound PK
Sorry for the duplicate postings, but I was getting errors on the submission.
April

Error in locating entity bean

Hi
when i tested my first session bean by IBM websphere Universal Test Client , i got the following error when execute getBookForPlatform(String workPlatform) saying error in locating entity bean Book_catalog and i tried to test Book_catalog entity bean and it's working successfuly but i do not know why seesion bean could not locate it ? :
========== the Error ===========
java.rmi.ServerException: RemoteException occurred in server thread; nested exception is:
java.rmi.RemoteException: ; nested exception is:
javax.ejb.EJBException: Error getting TechLibBook_catalogLocalHome from findByPlatform method:Error locating TechLibBook_catalogLocalHome: Context: localhost/nodes/localhost/servers/server1, name: ejb/Book_catalog: First component in name Book_catalog not found.
at com.ibm.CORBA.iiop.UtilDelegateImpl.mapSystemException(UtilDelegateImpl.java:156)
at com.ibm.CORBA.iiop.UtilDelegateImpl.wrapException(UtilDelegateImpl.java:684)
at javax.rmi.CORBA.Util.wrapException(Util.java:295)
at apress.wsad.techlib._TechLibFacade_Stub.getBookForPlatform(_TechLibFacade_Stub.java:267)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:79)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java(Compiled Code))
at java.lang.reflect.Method.invoke(Method.java(Compiled Code))
at com.ibm.etools.utc.model.ReflectionMethodModel.invoke(ReflectionMethodModel.java:68)
at com.ibm.etools.utc.servlet.InvokeServlet.invoke(InvokeServlet.java:110)
at com.ibm.etools.utc.servlet.InvokeServlet.doPost(InvokeServlet.java:366)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at com.ibm.ws.webcontainer.servlet.StrictServletInstance.doService(StrictServletInstance.java:110)
at com.ibm.ws.webcontainer.servlet.StrictLifecycleServlet._service(StrictLifecycleServlet.java:174)
at com.ibm.ws.webcontainer.servlet.IdleServletState.service(StrictLifecycleServlet.java:313)
at com.ibm.ws.webcontainer.servlet.StrictLifecycleServlet.service(StrictLifecycleServlet.java:116)
at com.ibm.ws.webcontainer.servlet.ServletInstance.service(ServletInstance.java:283)
at com.ibm.ws.webcontainer.servlet.ValidServletReferenceState.dispatch(ValidServletReferenceState.java:42)
at com.ibm.ws.webcontainer.servlet.ServletInstanceReference.dispatch(ServletInstanceReference.java:40)
at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.handleWebAppDispatch(WebAppRequestDispatcher.java:974)
at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.dispatch(WebAppRequestDispatcher.java:555)
at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.forward(WebAppRequestDispatcher.java:200)
at com.ibm.ws.webcontainer.srt.WebAppInvoker.doForward(WebAppInvoker.java:119)
at com.ibm.ws.webcontainer.srt.WebAppInvoker.handleInvocationHook(WebAppInvoker.java:276)
at com.ibm.ws.webcontainer.cache.invocation.CachedInvocation.handleInvocation(CachedInvocation.java:71)
at com.ibm.ws.webcontainer.cache.invocation.CacheableInvocationContext.invoke(CacheableInvocationContext.java:114)
at com.ibm.ws.webcontainer.srp.ServletRequestProcessor.dispatchByURI(ServletRequestProcessor.java:186)
at com.ibm.ws.webcontainer.oselistener.OSEListenerDispatcher.service(OSEListener.java:334)
at com.ibm.ws.webcontainer.http.HttpConnection.handleRequest(HttpConnection.java:56)
at com.ibm.ws.http.HttpConnection.readAndHandleRequest(HttpConnection.java:618)
at com.ibm.ws.http.HttpConnection.run(HttpConnection.java:439)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:593)
Caused by: java.rmi.RemoteException: ; nested exception is:
javax.ejb.EJBException: Error getting TechLibBook_catalogLocalHome from findByPlatform method:Error locating TechLibBook_catalogLocalHome: Context: localhost/nodes/localhost/servers/server1, name: ejb/Book_catalog: First component in name Book_catalog not found.
at com.ibm.ejs.container.RemoteExceptionMappingStrategy.mapEJBException(RemoteExceptionMappingStrategy.java:379)
at com.ibm.ejs.container.RemoteExceptionMappingStrategy.mapException(RemoteExceptionMappingStrategy.java:112)
at com.ibm.ejs.container.RemoteExceptionMappingStrategy.setUncheckedException(RemoteExceptionMappingStrategy.java:202)
at com.ibm.ejs.container.EJSDeployedSupport.setUncheckedException(EJSDeployedSupport.java:296)
at apress.wsad.techlib.EJSRemoteStatelessTechLibFacade_3526fe64.getBookForPlatform(EJSRemoteStatelessTechLibFacade_3526fe64.java:32)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:79)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java(Compiled Code))
at java.lang.reflect.Method.invoke(Method.java(Compiled Code))
at com.ibm.rmi.util.ProxyUtil$4.run(ProxyUtil.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at com.ibm.rmi.util.ProxyUtil.invokeWithClassLoaders(ProxyUtil.java:701)
at com.ibm.CORBA.iiop.ClientDelegate.invoke(ClientDelegate.java:1084)
at $Proxy1.getBookForPlatform(Unknown Source)
at apress.wsad.techlib._TechLibFacade_Stub.getBookForPlatform(_TechLibFacade_Stub.java:260)
... 29 more
Caused by: javax.ejb.EJBException: Error getting TechLibBook_catalogLocalHome from findByPlatform method:Error locating TechLibBook_catalogLocalHome: Context: localhost/nodes/localhost/servers/server1, name: ejb/Book_catalog: First component in name Book_catalog not found.
at apress.wsad.techlib.TechLibFacadeBean.getBookForPlatform(TechLibFacadeBean.java:92)
at apress.wsad.techlib.EJSRemoteStatelessTechLibFacade_3526fe64.getBookForPlatform(EJSRemoteStatelessTechLibFacade_3526fe64.java:22)
... 39 more
===== End of Error ======
====== the source code of session bean=======
package apress.wsad.techlib;
import javax.ejb.*;
import javax.naming.*;
import javax.rmi.*;
import java.rmi.*;
import java.lang.*;
import java.util.*;
public class TechLibFacadeBean implements javax.ejb.SessionBean
private javax.ejb.SessionContext mySessionCtx;
// Variable to keep the Home Local refernce to TechLibBook_catalog object
private TechLibBook_catalogLocalHome catalogLocalHome = null ;
// Method to get the Home Interface of the Book_catalog entity bean.
private TechLibBook_catalogLocalHome getCatalogLocalHome()
throws RemoteException
try
if (catalogLocalHome == null)
InitialContext initContext = new InitialContext();
Object objRef =initContext.lookup("ejb/Book_catalog");
catalogLocalHome = (TechLibBook_catalogLocalHome) objRef;
return (TechLibBook_catalogLocalHome) objRef;
else
return catalogLocalHome;
catch (NamingException ne)
System.out.println("Error locating TechLibBook_catalogLocalHome: " +
ne.getMessage());
throw
new RemoteException("Error locating TechLibBook_catalogLocalHome: " +
ne.getMessage());
// This business method must be promoted to the remote interface
public Vector getBookForPlatform(String workPlatform)
throws FinderException
Vector bookVector = new Vector();
TransportBean transObject;
TechLibBook_catalogLocal bookCatalogLocal = null;
Collection collBookRecords;
try
collBookRecords =
getCatalogLocalHome().findByPlatform(workPlatform);
Iterator iterator = collBookRecords.iterator();
while (iterator.hasNext())
bookCatalogLocal =
(TechLibBook_catalogLocal) iterator.next();
transObject = new TransportBean();
transObject.catalogNumber = bookCatalogLocal.getCatalog_number();
transObject.author = bookCatalogLocal.getAuthor();
transObject.bookTitle = bookCatalogLocal.getBook_title();
transObject.location = bookCatalogLocal.getLocation();
transObject.platform = bookCatalogLocal.getPlatform();
transObject.txnDate = bookCatalogLocal.getLanguage();
bookVector.addElement(transObject);
} // End of while
} // End of try
catch(FinderException fe)
System.out.println("Error executing findByPlatform method: " +
fe.getMessage());
throw
new EJBException("Error executing findByPlatform method: " +
fe.getMessage());
catch(Exception e)
System.out.println("Error getting TechLibBook_catalogLocalHome from findByPlatform method:" + e.getMessage());
throw
new EJBException("Error getting TechLibBook_catalogLocalHome from findByPlatform method:" + e.getMessage());
return bookVector;
public javax.ejb.SessionContext getSessionContext()
return mySessionCtx;
public void setSessionContext(javax.ejb.SessionContext ctx)
mySessionCtx = ctx;
* ejbCreate
public void ejbCreate() throws javax.ejb.CreateException
public void ejbActivate()
public void ejbPassivate()
public void ejbRemove()
==== End if source code =========
Please tell me what's the problem ?
with regards

i found what's the problem i made the url for lookup as the following:
lookup("java:comp/env/Book_catalog")
instead of
lookup("ejb/Book_catalog")
could anyone tell me what's the difference between 'java:comp/env/' and without it
by the way i used for lookup Datasource the following and it's working
DataSource dataSource = (DataSource)jndiContext.lookup("jdbc/TECHBOOK");
thanks

Deploying BMP Entity Bean with primary key calss

Hi,
I am using EJB 2.0 with and websphere studio 5.0 and database is sql server 2000.
My BMP Entity bean has a primary key class.From my client I am invoking the Entity Bean by calling it's findbyprimarykey method.
The home interface of my findbyprimarykey method returns a class of type Remote.But in the Entity Bean class,the return type is the primarykey class type.
My problem is invoking this findbyprimarykey from the client to get the remote interface so that the other business methods of the entity bean can be called.
The control goes into the ejbFindbyPrimaryKey but when it is returing from the Entity Bean class,it gives a remote exception (as the return type in Entity Bean class and Home interface are different for the findbyprimarykey method).
I think that somewhere in the deployment decriptor in my websphere,i have to specify the primarykey class type,which i am missing out and hence getting the error.
Please help me out with your advice and solution.
Thanks
Rahul Priyadarshi

Hi,
Sorry to disturb you again.
Even my code is also almost the same....i am pasting the code below...Please go through it and let me know if I have made any mistake..
EditVendorEntityBean.....(Bean Class)
package code.beans.EditVendor;
import code.beans.dataAccess.*;
import javax.ejb.CreateException;
import javax.ejb.RemoveException;
import javax.ejb.EntityBean;
import javax.ejb.EntityContext;
import javax.ejb.EJBException;
import javax.ejb.FinderException;
import javax.ejb.ObjectNotFoundException;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import java.sql.*;
import javax.sql.*;
import java.util.*;
* Bean implementation class for Enterprise Bean: EditVendorEntity
public class EditVendorEntityBean implements javax.ejb.EntityBean {
     private static Hashtable dataSources = new Hashtable();
     private String username;
private int Vendor_ID;
private int Category_Id;
private String Category_Name;
private String Vendor_Name;
private String Vendor_Address1;
private String Vendor_Address2;
private String Contact_Name;
private String Home_Phone;
private String Work_Phone;
private String email;
private String faxno;
private String userloginname;
private boolean dirtyFlag = false;
private EntityContext context;
private static final String DS_NAME = "jdbc/spiPOPS";
Connection con = null;
Statement stmt = null;
PreparedStatement st = null;
ResultSet res = null;
     //***********************Business Methods*********************
// Begin of Busines Methods
public void setData (String[] catname, String vendorname,String vendadd1,String vendadd2,String vendcontact,String venoff,String venres,String mailid,String venfax) {
          System.out.println("in setData where Vendor Id= "+ Vendor_ID);
               boolean status=false;
               boolean existing=false;
               ArrayList cat=new ArrayList();
               try
                    cat=getcategorylist(this.Vendor_ID);
               catch(SQLException e)
                    System.out.println("Could not get category list");
               System.out.println("Size of cat array -->" + cat.size() + " and string array size -->" + catname.length);
               if(catname.length>0)
                    //Removing unwanted vendor categories for a particular vendor id
                    for(int i=0;i<cat.size();i++)
                              existing=false;
                              String tempdata=(String)cat.get(i);
                              for(int j=0;j<catname.length;j++)
                                   if(tempdata.equals(catname[j]))
                                        existing=true;
                              if(!existing)
                                   try
                                        delvencat(this.Vendor_ID,tempdata.trim());
                                   catch(SQLException e)
                                        System.out.println("Could not delete record in POPS_VENDOR_CATEGORY for -->" + tempdata);
               //Adding new vendor categories for a particular vendor
                    try
                              for(int i=0;i<catname.length;i++)
                                   status=false;
                                   String strcat=catname;
                                   status=checkcat(this.Vendor_ID,strcat.trim());
                                   if(!status)
                                        insertvencat(this.Vendor_ID,strcat.trim());
                    catch(SQLException e)
                              System.out.println("Could not insert or select from POPS_VENDOR_CATEGORY table");
               this.Vendor_Name          =vendorname;
          this.Vendor_Address1     =vendadd1;
          this.Vendor_Address2     =vendadd2;
          this.Contact_Name          =vendcontact;
          this.Work_Phone               =venoff;
          this.Home_Phone               =venres;
          this.email                    =mailid;
          this.faxno                    =venfax;
               dirtyFlag = true;
               System.out.println("Leaving set data method");
public Vector getData() {
     Vector vctRec=new Vector();
     ArrayList arrdatas = new ArrayList();
     arrdatas.add(""+this.Vendor_ID);
     arrdatas.add(this.Vendor_Name);
     arrdatas.add(this.Vendor_Address1);
     arrdatas.add(this.Vendor_Address2);
     arrdatas.add(this.Contact_Name);
     arrdatas.add(this.Work_Phone);
     arrdatas.add(this.Home_Phone);
     arrdatas.add(this.email);
     arrdatas.add(this.faxno);
     vctRec.addElement(arrdatas);
     ArrayList cat=new ArrayList();
          try
          System.out.println("Calling getcategorylist from getdata with vendorid-->" + this.Vendor_ID);
          cat          = getcategorylist(this.Vendor_ID);
     catch(SQLException e)
               System.out.println("Could not get datas for category list");
     vctRec.addElement(cat);
     ArrayList allcats=new ArrayList();
     try
                    allcats          = getallcategorylist();
          catch(SQLException e)
                    System.out.println("Could not get datas for category list");
     vctRec.addElement(allcats);
          dirtyFlag = false;
     System.out.println("Before return statement in getdata with vector size -->" + vctRec.size());
          return vctRec;
// End of Business Methods
//**************************Entity Bean Methods*******************************
     * ejbActivate
     public void ejbActivate() {
          Vendor_ID = Integer.parseInt((String)context.getPrimaryKey());
     System.out.println("Inside ejbActivate Vendor_ID-->"+ Vendor_ID);
     * ejbLoad
     public void ejbLoad() {
          System.out.println("Inside ejbLoad ********" );
try {
loadRow();
}catch (Exception ex) {
          System.out.println("Failed in loadRow()");
throw new EJBException("ejbLoad: " +
ex.getMessage());
     * ejbPassivate
     public void ejbPassivate() {
     System.out.println("Inside ejbPassivate " );
Vendor_ID = 0;
     * ejbRemove
     public void ejbRemove() throws javax.ejb.RemoveException {
          //Empty Method
     * ejbStore
     public void ejbStore() {
System.out.println("Inside ejbStore " );
try {
storeRow();
}catch (Exception ex) {
          System.out.println("Exception thrown in storeRow" + ex.getMessage());
throw new EJBException("ejbLoad: " +
ex.getMessage());
     * getEntityContext
     public javax.ejb.EntityContext getEntityContext() {
          return context;
     * setEntityContext
     public void setEntityContext(javax.ejb.EntityContext ctx) {
          System.out.println("Inside setEntityContext " );
try{
     con = getConnection(DS_NAME);
     System.out.println("DB Connection Created!!");
catch(Exception e){
this.context = ctx;
     * unsetEntityContext
     public void unsetEntityContext() {
System.out.println("Inside unsetEntityContext " );
closeDbConnection(con, res, st);
this.context = null;
     * ejbCreate
     //code.beans.EditVendor.EditVendorEntityKey
     public code.beans.EditVendor.EditVendorEntityKey ejbCreate(String vendorid)
          throws javax.ejb.CreateException {
          return new EditVendorEntityKey(vendorid);
          //return null;
     * ejbPostCreate
     public void ejbPostCreate(String vendorid) throws javax.ejb.CreateException {
          //Empty
     * ejbFindByPrimaryKey
     //code.beans.EditVendor.EditVendorEntityKey
     public code.beans.EditVendor.EditVendorEntityKey ejbFindByPrimaryKey(
          code.beans.EditVendor.EditVendorEntityKey primaryKey)
          throws javax.ejb.FinderException {
try {
if(selectByPrimaryKey(Integer.parseInt(primaryKey.getVendorId()))) {
          System.out.println("Leaving the findbyprimarykey method from the entity bean");
     return primaryKey;
     //return null;
}else {
     throw new ObjectNotFoundException
     ("Row for id " + primaryKey + " not found.");
}catch (Exception ex) {
throw new EJBException("EXCEPTION IN ejbFindByPrimaryKey :- " + ex.getMessage());
     /*********************** Database Utility Routines *************************/
private boolean selectByPrimaryKey(int priKey)
throws SQLException {
     System.out.println("inside selectByPrimaryKey for primary key " + priKey);
String queryStr ="SELECT VENDOR_ID FROM POPS_VENDOR WHERE VENDOR_ID = " + priKey;
System.out.println("in selectByPrimaryKey where queryString is: "+ queryStr);
          stmt = con.createStatement();
ResultSet result = stmt.executeQuery(queryStr);
if(!result.next()) {
stmt.close();
     System.out.println("Did not find "+priKey);
return false;
else { //Found the primaryKey
Vendor_ID = result.getInt("VENDOR_ID");
stmt.close();
return true;
private void loadRow() throws SQLException {
          System.out.println("inside loadRow ...");
          stmt = con.createStatement();
          String queryStr = "SELECT VENDOR_NAME,VENDOR_ADDRESS1,VENDOR_ADDRESS2,CONTACT_NAME,HOME_PHONE,WORK_PHONE,EMAIL_ID,FAX_NO " +
                              "FROM POPS_VENDOR WHERE VENDOR_ID=" + Vendor_ID;
          System.out.println("Inside loadRow()***********"+queryStr);
          ResultSet result = stmt.executeQuery(queryStr);
          ArrayList catadatas=new ArrayList();
     if(!result.next())
     throw new SQLException("No record for primary key" + Vendor_ID);
          this.Vendor_ID               =Vendor_ID;
                    this.Vendor_Name          =result.getString("VENDOR_NAME");
                    this.Vendor_Address1     =result.getString("VENDOR_ADDRESS1");
                    this.Vendor_Address2     =result.getString("VENDOR_ADDRESS2");
                    this.Contact_Name          =result.getString("CONTACT_NAME");
                    this.Home_Phone               =result.getString("HOME_PHONE");
                    this.Work_Phone               =result.getString("WORK_PHONE");
                    this.email                    =result.getString("EMAIL_ID");
                    this.faxno                    =result.getString("FAX_NO");
                         System.out.println("Leaving loadrow method with loaded datas for vendor -->" + Vendor_ID);
                         stmt.close();
private ArrayList getcategorylist(int vendor) throws SQLException{
          String queryStr ="SELECT DISTINCT(VENDOR_CAT) FROM POPS_VENDOR_CATEGORY WHERE VENDOR_ID=" + vendor;
          System.out.println("Query for the cat list --> " + queryStr);
          stmt = con.createStatement();
          ResultSet result = stmt.executeQuery(queryStr);
          ArrayList catdatas=new ArrayList();
try{
               while(result.next())
                    catdatas.add(result.getString("VENDOR_CAT"));
          catch (SQLException e){
               stmt.close();
               System.out.println("Could not retrieve datas for Category list");
          stmt.close();
          System.out.println("size off array for cat -->" + catdatas.size() + " and datas ->" + catdatas);
          return catdatas;
     private ArrayList getallcategorylist() throws SQLException{
               //String queryStr ="SELECT DISTINCT(VENDOR_CAT) FROM POPS_VENDOR_CATEGORY";
               StringBuffer strquery=new StringBuffer(20);
               strquery.append("SELECT DISTINCT(CATEGORY_NAME) FROM POPS_CATEGORY");
               stmt = con.createStatement();
               //ResultSet result = stmt.executeQuery(queryStr);
               ResultSet result = stmt.executeQuery(strquery.toString());
               ArrayList catdatas=new ArrayList();
               try{
                    while(result.next())
                              //catdatas.add(result.getString("VENDOR_CAT"));
                              catdatas.add(result.getString("CATEGORY_NAME"));
               catch (SQLException e){
                         stmt.close();
                         System.out.println("Could not retrieve datas for All Category list");
               stmt.close();
               return catdatas;
     private void delvencat(int vendor,String vencat) throws SQLException {
          int update=-1;
          stmt = con.createStatement();
          String queryStr ="DELETE FROM POPS_VENDOR_CATEGORY WHERE VENDOR_ID = " + vendor + " AND VENDOR_CAT = '" + vencat.toUpperCase() + "'";
          System.out.println("Delete query --> " + queryStr);
          update= stmt.executeUpdate(queryStr);
          if(update!=1)
               System.out.println("Did not find data to delete");
          stmt.close();
     private void insertvencat(int vendor,String vencat) throws SQLException {
          int update=-1;
          String queryStr ="INSERT INTO POPS_VENDOR_CATEGORY(VENDOR_ID,VENDOR_CAT)" +
                              " VALUES(" + vendor +",'" + vencat + "')";
          System.out.println("Insert query --> " + queryStr);
          stmt = con.createStatement();
          update=stmt.executeUpdate(queryStr);
          if(update!=1)
               System.out.println("Could not insert records in the database");
          stmt.close();
     private boolean checkcat(int vendor,String catven) throws SQLException {
          boolean datastatus=false;
          String queryStr ="SELECT VENDOR_ID FROM POPS_VENDOR_CATEGORY WHERE VENDOR_ID = " + vendor + " AND VENDOR_CAT = '" + catven.toUpperCase() + "'";
          stmt = con.createStatement();
          ResultSet result = stmt.executeQuery(queryStr);
          datastatus=result.next();
          stmt.close();
          return datastatus;
private void storeRow() throws SQLException {
               System.out.println("Inside ejb store");
     if (!dirtyFlag) {
     System.out.println("Skipping the UPDATE because object is not dirty");
     return;
     CallableStatement cs=null;
try{
                    cs = con.prepareCall("EXEC POPS_VENDOR_UPDATE " + this.Vendor_ID + ",'" + this.Vendor_Name + "','" + this.Vendor_Address1 + "','" + this.Vendor_Address2 + "','" + this.Contact_Name + "','" + this.Work_Phone + "','" + this.Home_Phone + "','" + this.email + "','" + this.faxno +"'");
                    System.out.println("\n\n SQL Statement : \n " + "EXEC POPS_VENDOR_UPDATE " + this.Vendor_ID + ",'" + this.Vendor_Name + "','" + this.Vendor_Address1 + "','" + this.Vendor_Address2 + "','" + this.Contact_Name + "','" + this.Work_Phone + "','" + this.Home_Phone + "','" + this.email + "','" + this.faxno +"'");
                    cs.executeUpdate();
          catch (SQLException e){
                    cs.close();
                    System.out.     println("\n\n Error in calling stored procedure POPS_INSERT_NEW_REQUEST \n\n"+ e.getMessage() + "\n\n");
          cs.close();
          dirtyFlag = false;
     private Connection getConnection(String dbName) throws SQLException
          String configuredDataSourceName = null;
          if (dbName == null) {
               System.out.println("Attemp to get connection failed. The requested database name is null");
          DataSource dbSource = getDataSource(dbName);
          return dbSource.getConnection();
     private DataSource getDataSource(String dbName)
          // looking from cache;
          DataSource dbSource = (DataSource) dataSources.get(dbName);
          if (dbSource == null) { //we need to find it from JNDI
               try {
                    Context ic = new InitialContext();
                    dbSource = (DataSource) ic.lookup(dbName);
                    dataSources.put(dbName, dbSource);
               }catch (NamingException e){
          return dbSource;
     * User calls this function to safely close an connection
     * @param connt The connection a datasource
     * @param rs The resulSet inside this connection
     * @param statement The statement associate with this connection
     private void closeDbConnection(Connection cont,ResultSet rs,Statement statement)
          if (rs != null)
          try {
                    rs.close();
               } catch (SQLException ignored) {
                    ignored.printStackTrace();
          if (statement != null)
               try {
                    statement.close();
               } catch (SQLException ignored) {
                    ignored.printStackTrace();
          if (cont != null)
               try {
                    cont.close();
               } catch (SQLException ignored) {
                    ignored.printStackTrace();
     } //closeDbConnection
EditVendorEntity (Remote Interface)
package code.beans.EditVendor;
import javax.ejb.EJBObject;
import java.rmi.RemoteException;
import java.util.*;
* Remote interface for Enterprise Bean: EditVendorEntity
public interface EditVendorEntity extends javax.ejb.EJBObject {
     public void setData (String[] catname, String vendorname,String vendadd1,String vendadd2,String vendcontact,String venoff,String venres,String mailid,String venfax)
               throws RemoteException;
public Vector getData() throws RemoteException;
EditVendorEntityHome (Home Interface)
package code.beans.EditVendor;
import java.rmi.RemoteException;
import javax.ejb.CreateException;
import javax.ejb.FinderException;
import javax.ejb.DuplicateKeyException;
import javax.ejb.EJBHome;
import java.util.*;
* Home interface for Enterprise Bean: EditVendorEntity
public interface EditVendorEntityHome extends javax.ejb.EJBHome {
     * Creates an instance from a key for Entity Bean: EditVendorEntity
     public code.beans.EditVendor.EditVendorEntity create(String vendorid)
          throws javax.ejb.CreateException, java.rmi.RemoteException;
     * Finds an instance using a key for Entity Bean: EditVendorEntity
     public code.beans.EditVendor.EditVendorEntity findByPrimaryKey(
          code.beans.EditVendor.EditVendorEntityKey Vendor_ID)
          throws javax.ejb.FinderException, java.rmi.RemoteException;
EditVendorEntityKey (Primary Key Class)
package code.beans.EditVendor;
* Key class for Entity Bean: EditVendorEntity
public class EditVendorEntityKey implements java.io.Serializable {
     static final long serialVersionUID = 3206093459760846163L;
     public String primkey;
     * Creates an empty key for Entity Bean: EditVendorEntity
     public EditVendorEntityKey() { }
     public EditVendorEntityKey(String primarykey) {
          this.primkey=primarykey;
     public String getVendorId() {
return primkey;
     * Returns true if both keys are equal.
     public boolean equals(java.lang.Object otherKey) {
          if (otherKey instanceof code.beans.EditVendor.EditVendorEntityKey) {
               code.beans.EditVendor.EditVendorEntityKey o =
                    (code.beans.EditVendor.EditVendorEntityKey) otherKey;
               return (primkey.equals(otherKey));
          return false;
     * Returns the hash code for the key.
     public int hashCode() {
          return (primkey.hashCode());
Please go through and give me your comments and solution...
Thanks in advance
Rahul

Question on Persistence (Entity Beans, Hibernate, JDBC)

Hi everybody!
Until now, I have read a lot about persistence in the J2EE-sector, but I am still confused about which technology to used in my case.
I hope, that maybe you can give me some hints, by telling me which technology is good or bad regarding my requirements:
I want to build a customer- and order-management system fullfilling the following requirements:
1. The client is a Java application, the server is a JBOSS 4.0.1
2. The databasa scheme exists already and I'm not allowed to change it.
Some data, that logically belongs together and which shall be presented together to the client is distributed over 2 database tables.
3. The user cannot just create new and view data, but will also edit existing data quite often.
4. The user can assign products to an order. Often, there will be more than 1000 products assigned to an order, which will be presented to the user as a table (e.g. JTable). The user can then edit each cell of that 1000-row table, which of course will lead to an update in the db.
5. The user can also assign customers to a specific role in an order-process. On the other hand, each customer can make many orders.
So, we have a n:m relation here with the db-tables Customer, Order, OrderCustomer.
6. A complex search functionality has to be implemented, where the db-query is created dynamically at runtime.
7. The application is a multi-user application (about 10 users). It will be very rare, that users will work on the same data at the same time, but it might happen.
8. The database type (SAP DB) will not be changed in the near future.
With these 8 requirements in mind, I dealed a lot with EntityBeans, Hibernate and JDBC with SesseionBeans during the last 2 weeks.
Until now, I came to the following conclusions.
Hibernate is too slow. That'S bad, for data is edited very often and sometimes I want to edit just a single cell in 1000-row table.
Hibernate's biggest advantage - that it makes your application independent of the database type - is not even required (see point 8).
JDBC with SessioBeans: Very fast (I tried a simple query and it was about 10 times faster than Hibernate).
The disadvantage is, that I have to take care about all the transaction, concurrency control etc. things.
If I use JDBC, I want to do it that way: A SessionFacade accesses a DAO-object which executes the DB-query and returns the result to the SessionFacade which in the last step will pass the result to the client.
Entity Beans: I am completely confused with Entity Beans.
I read a lot about the CompositeEntity-Pattern for BMP. But on sun's J2EE Pattern page (http://java.sun.com/blueprints/corej2eepatterns/Patterns/CompositeEntity.html)
they said, that it's just useful when using the EJB 1.1 specification, because from EJB 2.0. the container or whatever will take care about lazy loading and store optimization.
So, from EJB 2.0. you should prefer using CMP-Beans with Container Managed Relationships (CMR), but as I heard, the dependent objects cannot be accessed and changed by the client when using CMPBeans with CMR.
However, a simple DB/Entity-mapping will not work in my case, because as mentioned above, there are thousands of products from the db to be managed at the same time. So here, I thought, the Composite pattern with its lazy loading strategy would be useful.
Furthermore, I have an n:m relationship in my database scheme, which is not trivial to map to entity beans. And don't forget that some related data is spread over 2 databse tables.
To sum it up, it would be very nice if some of you could clarify this perisistence nightmare, especially some clarification about if and how to use EntityBeans when having n:m relationships, editing data a lot, managing lots of table rows at once and having related data distributed over 2 database tables.
So, which technology would you prefer with the 8 requirements in mind? Hibernate, Entity Beans or JDBC with SessionBeans? Or would you prefer a mixed solution?
Thanx for every hint.
Regards,
egon

Here the requested information about the test:
Goal:
Find all customers, who's branches have the String "Branch" in their name.
Both times, a simple client accesses the same SessionBean in a JBOSS-Container.
This Bean has 2 methods. One accesses the DB via Hibernate (executeCriteria), the other one via JDBC (executeCriteriaJDBC).
The code to count the seconds of computation is as follows:
long startTime = System.currentTimeMillis();
List customerList = bean.executeCriteria(dc);
System.out.println("Hibernate: "+((System.currentTimeMillis()-startTime)/1000.0f)+" sek");
startTime = System.currentTimeMillis();
List customerListJDBC = bean.executeCriteriaJDBC(query);
System.out.println("JDBC: "+((System.currentTimeMillis()-startTime)/1000.0f)+" sek");
HIBERNATE:
CODE:
Branch Branch = new Branch();
Branch.setName("%Branch%");
Example example = Example.create(Branch);
DetachedCriteria dc = DetachedCriteria.forClass(Customer.class)
.createCriteria("branches").add(example.enableLike()).setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
QUERY:
select
        this_.UUID as UUID1_1_,
        this_.NAME as NAME1_1_,
        this_.CUSTOMERNO as CUSTOMERNO1_1_,
        this_.SHORTDESC as SHORTDESC1_1_,
        this_.LONGDESC as LONGDESC1_1_,
        this_.TAXNUMBER as TAXNUMBER1_1_,
        this_.SALESTAXID as SALESTAXID1_1_,
        this_.ACCOUNTHOLDER as ACCOUNTH8_1_1_,
        this_.BANKACCOUNT as BANKACCO9_1_1_,
        this_.BANKCODE as BANKCODE1_1_,
        this_.BANKNAME as BANKNAME1_1_,
        this_.AREA1TEXT as AREA12_1_1_,
        this_.AREA2TEXT as AREA13_1_1_,
        this_.AREA3TEXT as AREA14_1_1_,
        this_.AREA4TEXT as AREA15_1_1_,
        this_.AREA5TEXT as AREA16_1_1_,
        this_.CH_UUID as CH17_1_1_,
        this_.REFTEXT1 as REFTEXT18_1_1_,
        this_.REFTEXT2 as REFTEXT19_1_1_,
        this_.REFTEXT3 as REFTEXT20_1_1_,
        branch1_.UUID as UUID0_0_,
        branch1_.NAME as NAME0_0_,
        branch1_.ILN as ILN0_0_,
        branch1_.BRANCHID as BRANCHID0_0_,
        branch1_.SHORTDESC as SHORTDESC0_0_,
        branch1_.LONGDESC as LONGDESC0_0_,
        branch1_.BAGSRECEIVED as BAGSRECE7_0_0_,
        branch1_.CUSTOMER_UUID as CUSTOMER8_0_0_
    from
        CUSTOMER this_,
        BRANCH branch1_
    where
        this_.UUID=branch1_.CUSTOMER_UUID
        and (
            branch1_.NAME like ?
RESULT:
Customername: Customer_A
Customername: Customer_F
Customername: Customer_D
Customername: Customer_R
Customername: Customer_S
TIME:
Hibernate: 1.343 sek
JDBC:
QUERY:
Select distinct c.* from Customer c, Branch b where b.id=b.Customer_id and b.name like '%Branch%'
// After getting the result of the query: Create a list of Customer-objects. Set all attributes of each Customer-object.
RESULT:
Customername: Customer_R
Customername: Customer_A
Customername: Customer_S
Customername: Customer_D
Customername: Customer_F
TIME:
JDBC: 0.125 sek
The Customer.hbm.xml (auto-generated in Eclipse with Middlegen)
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
<hibernate-mapping>

<class
    name="hibernate.hibernate.Customer"
    table="CUSTOMER"
    lazy="false"
>
    <id
        name="uuid"
        type="java.lang.String"
        column="UUID"
    >
        <generator class="assigned" />
    </id>
    <property
        name="name"
        type="java.lang.String"
        column="NAME"
        length="100"
    />
    <property
        name="customerno"
        type="java.lang.Integer"
        column="CUSTOMERNO"
        length="5"
    />
    <property
        name="shortdesc"
        type="java.lang.String"
        column="SHORTDESC"
        length="50"
    />
    <property
        name="longdesc"
        type="java.lang.String"
        column="LONGDESC"
        length="100"
    />
    <property
        name="taxnumber"
        type="java.lang.String"
        column="TAXNUMBER"
        length="50"
    />
    <property
        name="salestaxid"
        type="java.lang.String"
        column="SALESTAXID"
        length="50"
    />
    <property
        name="accountholder"
        type="java.lang.String"
        column="ACCOUNTHOLDER"
        length="50"
    />
    <property
        name="bankaccount"
        type="java.lang.String"
        column="BANKACCOUNT"
        length="50"
    />
    <property
        name="bankcode"
        type="java.lang.String"
        column="BANKCODE"
        length="50"
    />
    <property
        name="bankname"
        type="java.lang.String"
        column="BANKNAME"
        length="50"
    />
    <property
        name="area1text"
        type="java.lang.String"
        column="AREA1TEXT"
        length="50"
    />
    <property
        name="area2text"
        type="java.lang.String"
        column="AREA2TEXT"
        length="50"
    />
    <property
        name="area3text"
        type="java.lang.String"
        column="AREA3TEXT"
        length="50"
    />
    <property
        name="area4text"
        type="java.lang.String"
        column="AREA4TEXT"
        length="50"
    />
    <property
        name="area5text"
        type="java.lang.String"
        column="AREA5TEXT"
        length="50"
    />
    <property
        name="chUuid"
        type="java.lang.String"
        column="CH_UUID"
        length="50"
    />
    <property
        name="reftext1"
        type="java.lang.String"
        column="REFTEXT1"
        length="50"
    />
    <property
        name="reftext2"
        type="java.lang.String"
        column="REFTEXT2"
        length="50"
    />
    <property
        name="reftext3"
        type="java.lang.String"
        column="REFTEXT3"
        length="50"
    />
    
    
    <set
        name="branches"
        lazy="true"
        inverse="true"
       cascade="all"
    >
        <key>
            <column name="CUSTOMER_UUID" />
        </key>
        <one-to-many
            class="hibernate.hibernate.Branch"
        />
    </set>
</class>
</hibernate-mapping>So, seems to me like Hibernate is also getting the data from the Branch-Table related to each Customer. Maybe this is the reason, why Hibernate is slower.
But as you can see in the mapping-File of the customer, I wanted Branches to be lazy loaded.
Do you have any ideas, why Hibernate is so much slower? Any hints for optimizing that code?
Do you have any further tricks to optimize Hibernate? Unfortunately I am not allowed to make changes at the database, so I cannot e.g. set indices for optimization.
However, I�m a Hibernate-Newbie. In fact, I just made this test and was very disappointed about its result, so I didn�t keep on working with Hibernate.
But maybe you can proof me, that Hibernate is a good choice. If so, do you have any good resources (links, books) that help working with Hibernate in connection with JBOSS, describe how to map n:m relationships, show how to work with large results and so forth?
Thanx for help,
egon

Can I deploy the entity bean in different jar files?

I have an application EAR, which contains several JARs. I have an entity bean A that has relationships with 2 other different entity beans B and C in the same DB. Now, I have to deploy this entity A together with B in AB.jar, and A with C in AC.jar. Both AB.jar and AC.jar are modules of the same application EAR file. They all use the same data sources to the same database, and named by different <ejb-name>.
I have no problem with deploying the app to WebLogic 8.1. But the JSP page accessing entity A got errors. Sometime, it got error complaining that the container-generated ejbFindAccount mehtod is abstract.
My questions are,
Can an entity bean be defined twice in 2 different jars?
When container load AB.jar and AC.jar, does it generate the finder methods twice?
I guess there are some name conflicts going on here. What should I do to avoid it?
Any comments are very much appreciated.

Thanks for your answer, but how can I use it in connection with relationships?



<ejb-relation id="View-FrameworkUser">
     <description></description>
     <ejb-relation-name>View-FrameworkUser</ejb-relation-name>
     <ejb-relationship-role>
          <ejb-relationship-role-name>Views-have-FrameworkUser</ejb-relationship-role-name>
          <multiplicity>Many</multiplicity>
          <relationship-role-source>
               <ejb-name>View</ejb-name>
          </relationship-role-source>
          <cmr-field>
               <cmr-field-name>frameworkUser</cmr-field-name><!-#- getter/setter -#->
               <cmr-field-type>java.util.Collection</cmr-field-type>
          </cmr-field>
     </ejb-relationship-role>
     <!-#- *************** -#->
     <ejb-relationship-role>
          <ejb-relationship-role-name>FrameworkUser-has-Views</ejb-relationship-role-name>
          <multiplicity>One</multiplicity>
          <relationship-role-source>
               <!-#- *******REFERENCE******** -#->
               <ejb-name>ejb_foo_jar2_ejb.jar#FrameworkUser</ejb-name>
               <!-#- *******REFERENCE******** -#->
          </relationship-role-source>
     </ejb-relationship-role>
</ejb-relation>
...this obviously doesn't work...
Do I have to write a new <entity> where I define the referenced entity?

Using Vectors in Entity Beans

Hello,
Can I use vectors in entity and store them in Tables directly as binary objects.I have tried making that bean but facing problem in retriving data from table using EJB-QL.Here are code snippets:
-------public abstract class CartEntityBean implements EntityBean {
     private EntityContext ctx;
     public abstract String getCartId();
     public abstract Vector getItems();
     public abstract void setCartId(String CartId);
     public abstract void setItems(Vector items);
public String ejbCreate(String cartId,Vector items) throws CreateException {
          setCartId(cartId);
          return cartId;
rest other methods omitted
public interface CartHomeInterface extends EJBHome{
public CartRemoteInterface create (String cartId,Vector items )throws CreateException,RemoteException ;
public CartRemoteInterface findByPrimaryKey(String pk) throws FinderException, RemoteException;
public Collection findmyItems() throws FinderException, RemoteException;
I am using Cloudscape as Database.
Please help weather I can use Complex objects in Entity Beans or Not

this is no good idea to store the cart-items as a java-vector. you should create a entity bean cart and a entity bean cartItem. then create a cmr between the two entity beans.

Does WLS 6.1 sp2 allow (bean managed) entity beans to have transaction mode NOTSUPPORTED?

Hi,
I have created two bean managed entity beans, User and Role, abstracting users
and groups in a ldap base. A User may have more than one Role. This is represented
by a (bean managed) 1:many relationship directed from User to Role. For some weird
reasons I get a transaction rollback when reading data, when transactions are
turned on (REQUIRED).
While we where running WLS 6.1 sp1 we had no problems with this as we could set
transaction to NOTSUPPORTED for these two EJBs. Due to other hickups we had to
upgrade to sp2 and suddenly the error reappears leading me to believe that NOTSUPPORTED
isn't allowed anymore by the WLS. I know that NOTSUPPORTED isn't required by the
EJB spec, but containers may support it and obviously WLS used to do just that.
I have not seen any change in the release notes of sp2 that indicates that this
behaviour has changed.
Does anybody know if WLS really doesn't support NOTSUPPORTED for enity beans anymore
in sp2?
If anybody are curiuos or have any good ideas, the stacktrace I get is:
javax.ejb.TransactionRolledbackLocalException: EJB Exception:
- with nested exception:
[javax.ejb.EJBException
- with nested exception:
[weblogic.transaction.RollbackException: Unexpected exception in beforeCompletion:
sync=weblogic.ejb20.internal.TxManager$TxListener@1c2906 - with nested exception:
[java.util.ConcurrentModificationException]]]
Start server side stack trace:
java.rmi.RemoteException: EJB Exception: ; nested exception is:
     javax.ejb.TransactionRolledbackLocalException: EJB Exception:
- with nested exception:
[javax.ejb.EJBException
- with nested exception:
[weblogic.transaction.RollbackException: Unexpected exception in beforeCompletion:
sync=weblogic.ejb20.internal.TxManager$TxListener@1c2906 - with nested exception:
[java.util.ConcurrentModificationException]]]
java.util.ConcurrentModificationException
     at java.util.LinkedList$ListItr.checkForComodification(LinkedList.java:535)
     at java.util.LinkedList$ListItr.next(LinkedList.java:476)
     at weblogic.ejb20.manager.DBManager.beforeCompletion(DBManager.java:370)
     at weblogic.ejb20.internal.TxManager$TxListener.beforeCompletion(TxManager.java:481)
     at weblogic.transaction.internal.ServerSCInfo.callBeforeCompletions(ServerSCInfo.java:551)
     at weblogic.transaction.internal.ServerSCInfo.startPrePrepareAndChain(ServerSCInfo.java:88)
     at weblogic.transaction.internal.ServerTransactionImpl.localPrePrepareAndChain(ServerTransactionImpl.java:980)
     at weblogic.transaction.internal.ServerTransactionImpl.globalPrePrepare(ServerTransactionImpl.java:1504)
     at weblogic.transaction.internal.ServerTransactionImpl.internalCommit(ServerTransactionImpl.java:216)
     at weblogic.transaction.internal.ServerTransactionImpl.commit(ServerTransactionImpl.java:190)
     at weblogic.ejb20.internal.BaseEJBLocalObject.postInvoke(BaseEJBLocalObject.java:207)
     at com.takecargo.domainentities.role.RoleBean_1ipw6_ELOImpl.getName(RoleBean_1ipw6_ELOImpl.java:86)
     at com.takecargo.domainentities.role.RoleConverter.getVOforRoleLocal(RoleConverter.java:51)
Any kind of help would be appreciated:)
Regards,
Brynjar Glesnes

WLS support NotSupported on Entity Beans.
It looks like you've hit a bug in the EJB container where an internal Collection class has been modified while the
container is running through an iterator on it.
You should open a case with [email protected]
-- Rob
Brynjar Glesnes wrote:
Hi,
I have created two bean managed entity beans, User and Role, abstracting users
and groups in a ldap base. A User may have more than one Role. This is represented
by a (bean managed) 1:many relationship directed from User to Role. For some weird
reasons I get a transaction rollback when reading data, when transactions are
turned on (REQUIRED).
While we where running WLS 6.1 sp1 we had no problems with this as we could set
transaction to NOTSUPPORTED for these two EJBs. Due to other hickups we had to
upgrade to sp2 and suddenly the error reappears leading me to believe that NOTSUPPORTED
isn't allowed anymore by the WLS. I know that NOTSUPPORTED isn't required by the
EJB spec, but containers may support it and obviously WLS used to do just that.
I have not seen any change in the release notes of sp2 that indicates that this
behaviour has changed.
Does anybody know if WLS really doesn't support NOTSUPPORTED for enity beans anymore
in sp2?
If anybody are curiuos or have any good ideas, the stacktrace I get is:
javax.ejb.TransactionRolledbackLocalException: EJB Exception:
- with nested exception:
[javax.ejb.EJBException
- with nested exception:
[weblogic.transaction.RollbackException: Unexpected exception in beforeCompletion:
sync=weblogic.ejb20.internal.TxManager$TxListener@1c2906 - with nested exception:
[java.util.ConcurrentModificationException]]]
Start server side stack trace:
java.rmi.RemoteException: EJB Exception: ; nested exception is:
javax.ejb.TransactionRolledbackLocalException: EJB Exception:
- with nested exception:
[javax.ejb.EJBException
- with nested exception:
[weblogic.transaction.RollbackException: Unexpected exception in beforeCompletion:
sync=weblogic.ejb20.internal.TxManager$TxListener@1c2906 - with nested exception:
[java.util.ConcurrentModificationException]]]
java.util.ConcurrentModificationException
at java.util.LinkedList$ListItr.checkForComodification(LinkedList.java:535)
at java.util.LinkedList$ListItr.next(LinkedList.java:476)
at weblogic.ejb20.manager.DBManager.beforeCompletion(DBManager.java:370)
at weblogic.ejb20.internal.TxManager$TxListener.beforeCompletion(TxManager.java:481)
at weblogic.transaction.internal.ServerSCInfo.callBeforeCompletions(ServerSCInfo.java:551)
at weblogic.transaction.internal.ServerSCInfo.startPrePrepareAndChain(ServerSCInfo.java:88)
at weblogic.transaction.internal.ServerTransactionImpl.localPrePrepareAndChain(ServerTransactionImpl.java:980)
at weblogic.transaction.internal.ServerTransactionImpl.globalPrePrepare(ServerTransactionImpl.java:1504)
at weblogic.transaction.internal.ServerTransactionImpl.internalCommit(ServerTransactionImpl.java:216)
at weblogic.transaction.internal.ServerTransactionImpl.commit(ServerTransactionImpl.java:190)
at weblogic.ejb20.internal.BaseEJBLocalObject.postInvoke(BaseEJBLocalObject.java:207)
at com.takecargo.domainentities.role.RoleBean_1ipw6_ELOImpl.getName(RoleBean_1ipw6_ELOImpl.java:86)
at com.takecargo.domainentities.role.RoleConverter.getVOforRoleLocal(RoleConverter.java:51)
Any kind of help would be appreciated:)
Regards,
Brynjar Glesnes

Wrong version of an entity bean object being updated

We are having a problem with an entity bean that uses bean managed persistence. The "order" entity bean has
been used as part of our Order Routing System for the last 2 years with no problems. The entity bean is
accessed via calls from a "Order Manager" session bean. No change has been done to the entity bean but the
frequency of calls from the session bean to update the entity bean have increased significantly.
The "order" entity bean wraps an Order object that contains order properties (i.e. id, quantity, price,
version, etc). The entity bean has a "void setOrder(Order param)" function that writes the Order to a database
and a "Order getOrder()" function that clones and returns the internal Order object. The "ejbLoad()" function
reads the Order object from the database and the "ejbStore()" function is not implemented.
The "OrderEntityPK ejbFindByPrimaryKey()" function checks if the order entity primary key (an "int") exists
on the database.
We are using the SilverStream 3.5 application server as our EJB container. According to the SilverStream manual
it does not maintain a pool of idle/unused entity beans, instead it instantiates beans as requested.
Our problem is:
1) The wrong version of the entity object is sometimes being updated (i.e. an old instance of the order entity is being
picked up and updated on the database).
2) We sometimes get a TransactionRequired exception thrown when we have concurrent updates to two different
objects of the entity bean.
Any idea as to what our problem could be?
Thanks in advance for your help,
The following are the main code snippets:
Original Code
Session Bean A
Method 1 --- gets entity Bean B and calls a method on a different object passing this entity bean
          in as a parameter to enable a method on this bean to be called.
EntityBean lOrderEntity = findOrderEntity(callerUnixLogin, currOrderId);
               currOrder = lOrderEntity.getOrder();
               //Logic to update the currOrder object via a method call.
               persistManager.persistOrder(lOrderEntity, callerUnixLogin, currOrder, psTransactionType);
     persistManager.persistOrder Method:
               lOrderEntity.setOrder(callerUnixLogin, order);
     findOrderEntity method:
OrderEntity lOrderEntity = null;
          OrderEntityBeanPK orderPK = new OrderEntityBeanPK(orderId);
          try
               if (orderEntityHome == null)
                    connectToOrderEntityBean(callerUnixLogin);
               lOrderEntity = orderEntityHome.findByPrimaryKey(orderPK);
          ... etc
Current Code
Session Bean C
Method 2 ---- calls method 1 in Session Bean A
Calls to method 2 above happens in quick succession.
OrderEntityBean class
... important methods ...
     private Order order = null;
     public OrderEntityBeanPK ejbFindByPrimaryKey(OrderEntityBeanPK primaryKey)
          throws FinderException, RemoteException, DBOException
          try
               orderObjectManager.orderIdExists(primaryKey.orderId);
          catch (OMOrderValidationException exc)
               throw new FinderException(exc.getMessage());
          return primaryKey;
     public void setOrder(String userUnixLogin, Order newOrder)
          throws EJBException, RemoteException, DBOException, OMFormattingException, OMOrderValidationException
          callerUnixLogin = userUnixLogin;
          int version = newOrder.getOrderVersion().intValue();
          if (order.getOrderVersion().intValue() == version)
               order = null;
               order = newOrder;
               Integer newVersion = new Integer(version + 1);
               order.setOrderVersion(newVersion);
               newVersion = null;
               order.setSysUser(callerUnixLogin);
               orderObjectManager.updateOrder(callerUnixLogin, order);
          else
               Debug.Print(userUnixLogin, "OrderEntityBean.setOrder: wrong version number for order " + newOrder.getOrdId() +
                    ": expected " + order.getOrderVersion() + " and got " + newOrder.getOrderVersion(), 0);
               throw new OMOrderValidationException("wrongVersion", order, order.getOrdId(), IName.Order.VERSION, newOrder.getOrderVersion());
     public Order getOrder()
          throws EJBException, RemoteException
return ((Order)order.clone());
The following transactions exists for the entity bean ...
Required:
     create and setOrder methods
Not Supported
     findByPrimary and getOrder methods

"The entity bean has a "void setOrder(Order param)" function that writes the Order to a database"
This functionality should be performed in the ejbStore method().
"a "Order getOrder()" function that clones and returns the internal Order object."
Sounds reasonable, except for the cloning part.
"The "ejbLoad()" function reads the Order object from the database"
Cool.
""ejbStore()" function is not implemented."
Whoops. Looks like your setOrder method is doing too much. It should do the inverse of getOrder (namely, setting the interal Order object), nothing more. Defer the persistence code to the ejbStore method.
"According to the SilverStream manual it does not maintain a pool of idle/unused entity beans, instead it instantiates beans as requested."
Manual? What's that? Assuming that is correct, better hope you don't ever get a high load. You might wanna look into JBoss.
"2) We sometimes get a TransactionRequired exception thrown when we have concurrent updates to two different objects of the entity bean."
How can you have concurrent access to two different objects?? Concurrency is inherently applicable to only one object.
In summary:
Write your beans properly, ejbLoad populates the bean with data, ejbStore persists the bean's data.
Get a better (and possibly free) appserver.

Problem with a 1:M relationship between two entity beans

I am having trouble trying to implement a 1:M relationship between two EJB2.0 entity beans using and EJBQL query. I have an ApplicantEJB, which contains a collection of phone numbers. The applicant table in the database has one primary key, applicant_id. The applicant_phones database table has a compound primary key--applicant_id and phone_type_id--so I have implemented a custom PK class to represent this, PhonePK. I have implemented a findByNameAndPhone method in my ejb-jar.xml file with the following syntax:
SELECT object(a) FROM applicants a, applicant_phones p where a.applicantID = p.applicantID and a.name = ?1 and p.phoneNumber = ?2
If I deploy this, Orion/OC4J translates the query in the orion-ejb-jar.xml with an incorrect reference to the applicant_phones.applicant_id column:
SELECT a.applicant_id FROM applicants a , applicant_phones p WHERE ((a.applicant_id = p.applicantID ) AND (a.name = ?) AND (p.phone_number = ? ))
I must have something wrong with the ApplicantEJB and PhoneEJB primary key mappings in my orion-ejb-jar.xml file, but I have tried many different combinations of values and keep getting them overwritten by the container with each deployment. Why is Orion/OC4J defaulting the applicant_id reference to the ob[i]Long postings are being truncated to ~1 kB at this time.

I have posted excerpts from my orion-ejb-jar.xml file in this posting: Problem mapping a 1:M relationship between two entity EJBs w/ a compound PK
Sorry for the duplicate postings, but I was getting errors on the submission.
April

CMP Entity Beans / DB activity

Hello everyone
I'm using BEA Weblogic ejbgen for generating entity bean implementations and interfaces.
When I use the finder methods defined in the home-interface, naturally an sql-query is performed to the predefined database.
When I use the set-methods in the remote interface, is an sql-update performed on each method-invocation? in other words, if the entity has a lot of fields, and each field is populated with a seperate set-method, there will be a lot of databse activity while performing this update on the entity?
I'm trying to analyze a system, and there is a lot of activity goin on. A lot of remote calls and even more entity-operations.
First, 60 000 remote method calls are performed in a row. These return certain id's that are used for finding entity objects and performing operations on them. Lucky me...
Thx.
Juha, SCJP
----

Hello ,
Instead of exposing a get/set method for each arribute of your bean (corresponding to database table) expose only one object.
For example
public class CustomerBean implements javax.ejb.EntityBean{
private CustomerVO objCustomer;
private String customerName;
private String customerMail;
private String customerType;
public CustomerVO getCustomer(){
return this.objCustomer;
public void setCustomer(CustomerVO objCustomer){
this.objCustomer = objCustomer;
public void ejbStore(){
customerName = objCustomer.getName();
customerMail = objCustomer.getMail();
customerType = objCustomer.getType();
HTH
VJ

Entity beans not understood

hello,
I am new to ejb. I know that I have come to the right technology and now to the right forum. I have got quite a good grasp on session beans but I don't understand the entity beans.
I have a couple of questions.
Firstly if every bean represents a single record in a database then what's th logic behind having these beans in the first place. suppose I have about 10 milion records in one of my table then does that mean I have 10000000 instences of that entity bean? and what will be the advantage of such an arrangement.
secondly, do I always need entity beans to manage data from a database? I mean what is wrong if I do all that in a session bean? I do connect to a database with jdbc in servlets and jsp, so what is the problem in doing same in a session bean.
and one general question, how heavy is the remote object on the client machine, what I am asking is, if when I locate the bean using the home interface or home object if you like it, I get access to the remote object. so how heavy is the remote object when I download it on my client machine?
thanks
Krishnakant.

Hi,
If you want to have 10 million records it is not necessarily 10 million Entity Beans will be instatiated. EJB container pools the EntityBeans and uses then accordingly.
Writing DataBase code in Servlets/JSP is not a good idea. If you want to get the benefits of layered Architecture we have to follow certain design patterns. DB operations can be handled trhu EntityBeans are DAO factories.

Implementation of Entity Beans

Hi..
Can anyone help me in my doubts?
Whenever i have an entity bean object , and say at given instant of time more tan one user wants to update the data that the entity bean represent.
Take a particular case:
One user calls an entity bean modifies itzz state say one field but doesn't commit , now at the same time some other user modifies the state say another field and commits it.
What will happen to the modification made by the first user?are they lost or they are also commited with it.Now the first user undo itzz changes and commit it . What will be the state of the entity bean?
Thankzz in advance !!
Somilj

You first need to understand why two users would update the same row at the same time, and then define what you wish the expected results to be (the behaviour of locking all other users whilst one user updates data may be what you require).
Once you understand your desired behaviour, you can then consider how isolation levels and transactions help achieve that behaviour.
Loosely speaking, you can consider a transaction as an atomic operation on data in a database (enterprise resource), and Isolation levels as how that data may be manipulated when held in a transaction.
You can set isolation levels per entity bean method (e.g. SERIALIZABLE or REPEATABLE_READ) and indicate, per session bean method how it partakes in any transaction (e.g.TX_REQUIRED or TX_NOT_SUPPORTED).
For example, suppose you need to set some data in a row, perform a lot of other calculations controlled by a session bean, using other session and entity beans, then allow that data to be changed by someone else. To do so, it is likely that you would include all entity/session beans in a container managed transaction with the isolation level for the data set to serializable. Here the data would be 'locked' until the complete operation had finished.
Suppose you only need to lock the data for a small part of the overall computation, then you could choose to use several container managed transactions, or place the update of data outside a transaction, or use explicit Bean Managed Transactions (where the code you right manages the transaction).
Adam
Hi..
Can anyone help me in my doubts?
Whenever i have an entity bean object , and say at
given instant of time more tan one user wants to
update the data that the entity bean represent.
Take a particular case:
One user calls an entity bean modifies itzz state say
one field but doesn't commit , now at the same time
some other user modifies the state say another field
and commits it.
What will happen to the modification made by the first
user?are they lost or they are also commited with
it.Now the first user undo itzz changes and commit it
. What will be the state of the entity bean?
Thankzz in advance !!
Somilj

Entity Beans /JDO and Datawarehousing

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