Returning Resultsets in EJB

Hi ,
I want to return the resultset of a database query through an EJB (Stateless Session bean). However as per EJB specs, since a resultset is not serializable so it can not be returned directly. I read that sun provides a CachedRowSet for this purpose. However I am unable to locate the class/package file for this. If anyone of you can provide me a link to the file, it will be a big help to me.
Another solution I found was to convert the resultset into a collection(HashMap or ArrayList) and then return that. Which one is better- HashMap or ArrayList?
If there is any other better solution, please let me know.
Thanks in advance!!
regards,
Manish

RowSet is part of J2SE 5.0 (previously 1.5).
You can download the rowset reference implementation from http://java.sun.com/products/jdbc/download.html#rowset1_0_1
I have used ArrayList myself, but you can easily test the performance in your case to see which is more efficient.

Similar Messages

Help! Need oracle help with constructing stored procedure that return resultsets

Suns tutorial path for returning resultsets from stored procedures indicates that the following should work...
CallableStatement cs = con.prepareCall("{call SHOW_SUPPLIERS}");
ResultSet rs = cs.executeQuery();
Thats if you build your stored procedure something like this ...
String createProcedure = "create procedure SHOW_SUPPLIERS " + "as " + "select SUPPLIERS.SUP_NAME, COFFEES.COF_NAME " + "from SUPPLIERS, COFFEES " + "where SUPPLIERS.SUP_ID = COFFEES.SUP_ID " + "order by SUP_NAME";
We are using oracle 8.1.6. However I've been told that with oracle procedures when you return a result set from a called procedure you return a p_cursor variable. Somthing like this
(p_cursor in out SHOW_SUPPLIERS.SHOCurTyp)
is
begin
open p_cursor for
select * from suppliers
In which case the above mentioned sun code doesn't work.
We want to use jdbc to call a stored procedure that returns a resultset that does not require us to import any proprietary oracle objects...
Is there another way to write these stored procedures, rather than using this cursor construct? Are we missing something in the way we invoke them?

Suns tutorial path for returning resultsets from stored procedures indicates that the following should work...
CallableStatement cs = con.prepareCall("{call SHOW_SUPPLIERS}");
ResultSet rs = cs.executeQuery();
Thats if you build your stored procedure something like this ...
String createProcedure = "create procedure SHOW_SUPPLIERS " + "as " + "select SUPPLIERS.SUP_NAME, COFFEES.COF_NAME " + "from SUPPLIERS, COFFEES " + "where SUPPLIERS.SUP_ID = COFFEES.SUP_ID " + "order by SUP_NAME";
We are using oracle 8.1.6. However I've been told that with oracle procedures when you return a result set from a called procedure you return a p_cursor variable. Somthing like this
(p_cursor in out SHOW_SUPPLIERS.SHOCurTyp)
is
begin
open p_cursor for
select * from suppliers
In which case the above mentioned sun code doesn't work.
We want to use jdbc to call a stored procedure that returns a resultset that does not require us to import any proprietary oracle objects...
Is there another way to write these stored procedures, rather than using this cursor construct? Are we missing something in the way we invoke them?

Is it advisable to return ResultSet?

Hi,
I am studying one java code to enhance its performance.
In that code,
there is one method called getAccountingLines() that returns ResultSet.
This method is called at different 8 places in the entire code.
// pseudo code for getAccountingLine method
private ResultSet getAccountingLines(String fsDocCD, String fsDocDeptCd, String fsDocId, String fsDocVersNo, String fsTableName, String fsVendCustCd)
ResultSet lrs = null;
StringBuffer loQuery = new StringBuffer(1440);
Form the Select query(large in size) and assign it to loQuery.
try
lrs = (ResultSet)( moSession.getResultSetBySQL (loQuery.toString(),
moSession.getDataServerForObject(fsTableName),100));
return lrs
catch (Exception E)
System.err.println("Error Executing Query for getting the Accounting Lines information");
return null;
// code where getAccounting method is called
private void processStmtDetVectors(Vector fvStmtDetPABL, Vector fvStmtDetCC, Vector fvStmtDetPYM,
boolean fbCanAddToHist, R_ADImpl foAd, String fsBillLocCd,boolean fbCanAddToDet,String fsStmtType) throws Exception
ResultSet loResSet = null;
try
loResSet = getAccountingLines(lsDocCd,lsDocDeptCd,lsDocId,lsDocVersNo,"RE_DOC_ACTG",lsVendCustCd);
if (loResSet != null)
catch(Exception e)
finally
if (loResSet!=null )
loResSet.close();
Now my question is :
Is the reference of ResultSet instance(lrs) of getAccountingLine() method is closed with ResultSet instance(loResSet) of callee method(processStmtDetVectors) closed.
What I understand from above is references of ResultSet instance(lrs) of getAccountingLine() method are not closed with ResultSet instance(loResSet) of callee method(processStmtDetVectors) closed. If it remains open, it can creat memory problems.
Is it advisable to return ResultSet?
I think, method should return String (Query Statement) and at the place where method called, query should fire.
Let me know whether my understanding regarding this is true or not.
Anything else if any one can add to this, please let me know.
This will be very helpful to me.
Thanks in advance,
Deepalee

As a general rule, no, there is nothing wrong with returning a ResultSet (I do it myself all the time). You just have to be careful not to access it after the Statement or Connection go out of scope or are closed. If you do, you're liable to get a NullPointerException or something equally nasty.

Best practise for returning data from EJB's

I have an EJB that runs a query on a backend database and i want to return the data back to my Java GUI. Ideally i would like to pass a ResultSet back but i don't think they are serialisable so this isn't an option.
What's considered the best way to pass database results back from EJB's to a front end Java application ?
Thanks for any ideas you guys have

If you want type-safety, define a VO (value object) that maps to your result-set, extract the data from the result set into the VO, and return an array of the data. Yes, it's extra work on the "back-end," but that's what the back-end is for. Just make sure your client.jar has the VO in it, as well as the Home and Remote interfaces.

How to return ResultSet from one function to another?

Hi friends,
Greetings.
How do we pass the query Results from one function to another function?
Actually i have a database in the server and i am the client.
Client sends the id to the server as an argument. From HTML file this goes to the JSP file(which i am using as a link between HTML and EJB) and then this goes to the RemoteInterface and then to the Bean itself. The functions are written in the bean. Bean connects to the database using jdbc:odbc driver and then a query is written and executed as follows:
In the Stateless Session Bean, there is one function with the following query.
public ResultSet check(String id)
//other code
ResultSet rs = Statement.("select * from table1 where id=123");
if(!rs.next)
// print no such id exists. other ids are
rs=Statement.("select * from table1");
return rs;
I have written it approximately only because the problem is not with the query :(
Now, in rs there's a resultset. Now how do i display it in a tabular format in HTML? This should obviously be done using JSP. How can we do it?
In JSP file if i write
ResultSet rs1=Remote.check(12);
i get NullPointerException
Thank you in anticipation to your reply!
Regards

Crossposted over all places:
[http://forums.sun.com/thread.jspa?threadID=5336533]
[http://forums.sun.com/thread.jspa?threadID=5336534]
[http://forums.sun.com/thread.jspa?threadID=5336532]
[http://forums.sun.com/thread.jspa?threadID=5336519]
[http://forums.sun.com/thread.jspa?threadID=5336510]
Stop crossposting. It's very rude.

Dynamic implementation download for return values from EJB

I try the following exemplary scenario regarding dynamic implementation download. Let's say there is a statless EJB deployed (e.g. OrderHandler) with a method getSomeOrder() returning Order object; where Order is actually an interface extending java.io.Serializable. For Order there is implementation class OrderImpl. Within the getSomeOrder() the EJB creates a new OrderImpl, populates it and returns as interface. The client looks up OrderHandler and calls getSomeOrder() method. Then, on Order a dummy: String getName() method is called.
Now, the problem is various behavior with implementation dynamic download. I receive different behavior from 2 clients (1st being launched from within LAN with the server, 2nd from outside server's LAN). When I put OrderImpl in clients' classpaths, obviously they both work the same. When I leave only Order interface (!!the very goal of the test - dynamic impl. download!!), only the 1st client still works. I measured times in milis, and it looks that the OrderImpl is really downloaded, as the first getSomeOrder() call lasts around 10 times as long as further calls.
The 2nd client hangs a while on the getSomeOrder() call and then throws UnmarshallException, stating that it has failed to unmarshal the returned object, which basically means no implementation got downloaded.
Can anyone help?

You can try putting the Impl classes on a webserver.
while starting the server set the property
-Djava.rmi.server.codebase=http://mywebserver:8080
While running the client if the impl classes are not available in the classpath, it would download it from the webserver

Return ResultSet Method

What am I doing wrong to get a "cannot return symbol" error? The code is:
public ResultSet dataSet(){
     String DRIVER="com.mysql.jdbc.Driver";
     try {
     Class.forName(DRIVER);
          //get a recordset;
          Connection conn = DriverManager.getConnection ("jdbc:mysql://localhost/fms");
          Statement stmt = conn.createStatement ();
          ResultSet rset = stmt.executeQuery ("select * from filename");
          //return rset;
     catch(Exception e){
     System.out.println(e);
     return rset;
     }

easy, because the declaration of rset is only in scope inside the try block.
once you leave it's out of scope.
that might be a good thing, because you really don't want to return a ResultSet. Better to load that info into an object or data structure and close the ResultSet immediately in a finally block.
Lots of bad things in your code:
(1) Hard-wired driver and URL - should externalize
(2) You don't close your Connection, Statement, or ResultSet.
(3) Print the stack trace in the catch block, it might actually help you figure out any problems.
(4) No connection pooling.
%

Returning ResultSet to jsp from servlet

Hi,
I am trying to return a ResultSet (generated in servlet) to a jsp page, but get a "java.lang.ClassCastException" error. Here is my description of what i'm doing....
I have a search screen (SearchInventory.jsp) that the user goes to to perform the search based on a few variables. When the search button is clicked, i go to a servlet (SearchInventory.java) which gets a ResultSet. In the servlet, i am storing the ResultSet into a bean object, and finally use the RequestDispatcher to redirect to the .jsp page. (and get the "java.lang.ClassCastException" error).
Here is the relevant code from all parts of the app:
SearchInventory.java:---------------------------------------------------------------------
SearchBean sbean=new SearchBean();
String QueryStr="select ProdName from products";
Statement stmt=conn.createStatement();
rs=stmt.executeQuery(QueryStr);
sbean.setSearchRS(rs);
req.getSession(true).setAttribute("s_resbean",sbean);
HttpSession session=req.getSession(true);
session.setAttribute("s_resbean",rs);
req.setAttribute("sbean",rs);
String url="/SearchInventory.jsp";
RequestDispatcher dispatcher=getServletContext().getRequestDispatcher(url);
dispatcher.forward(req,res);
SearchBean.java:
public class SearchBean extends HttpServlet{
private int searchFlag=0;
private static ResultSet searchRS;
public void setSearchRS(ResultSet rs){
this.searchRS=rs;
And finally, the .jsp page..SearchInventory.jsp:
<%@ page language="java" import="java.lang.*,java.sql.*,javax.sql.*,PopLists.PopInvLists,beans.SearchBean"%>
<jsp:useBean scope="session" id="s_resbean" class="beans.SearchBean" />
ResultSet search=(ResultSet)request.getAttribute("s_resbean");
If i don't cast it to type ResultSet, i get the following error, which leads me to believe that i should be casting it to a Result Set.
C:\Apache\tomcat_4.1.29\work\Standalone\localhost\DBTest\SearchInventory_jsp.java:75: incompatible types
found : java.lang.Object
required: java.sql.ResultSet
ResultSet search=request.getAttribute("s_resbean");
Please help...
Thanks in advance,
Aditya.

Yikes...i realized some of my many problems...i'm using setAttribute multiple times here...(shown by arrows at the end)
sbean.setSearchRS(rs);
req.getSession(true).setAttribute("s_resbean",sbean);//<--
HttpSession session=req.getSession(true);
session.setAttribute("s_resbean",rs);//<--
req.setAttribute("sbean",rs);//<--
I've tried using one at a time since, and it still doesn't work. How exactly should i be setting the attribute. I don't think any of the methods listed above are completely correct...cause it's never worked!:(
Is anything that i've done correct? (ie. bean/jsp). I'm really starting to doubt myself now. I've been reading up on this, and some people say that one shouldn't return a ResultSet to the jsp, but instead return an ArrayList. Is this correct? If so, how do i convert an ResultSet to an ArrayList?
-Aditya.

Pass variables and return ResultSet from same preparedStatement

I am passing "fp" and "week_no" to a preparedStament in a class and want to return the values to my jsp page. "fp" and "week_no" are used twice. Please see below. When I run it, I get no error messages but, it doesn't display any data.
I have the following code in a class:
public ResultSet getHistory(String fp, String week_no)
                    throws SQLException, Exception {
ResultSet rs = null;
if (con != null) {
try {
     PreparedStatement getHist;
     getHist = con.prepareStatement(
     "SELECT sbu, TO_CHAR(((sum_dollar) + (adj_sum_dollar)),'$999,999,999.99') AS sum_dollar, TO_CHAR(actual_date,'MM/DD/YY') AS actual_date, " +
     "((sum_cases) + (adj_sum_cases)) AS sum_cases, " +
     "((new_order_cases) + (adj_new_order_cases)) AS new_order_cases, " +
     "((total_open_orders) + (adj_total_open_orders)) AS total_open_orders, " +
     "((back_orders) + (adj_back_orders)) AS back_orders, " +
     "TO_CHAR((sum_dollar/sum_cases), '999.99') AS yield " +
     "FROM SUMMARY " +
     "WHERE actual_date BETWEEN (SELECT begin_dt " +
               "FROM fiscal_calendar " +
                         "WHERE fiscal_period = '?' " +
                         "AND week_number = '?' " +
                         "AND week_number <> '9' " +
                         "AND fiscal_yr = '2003') " +
                    "AND " +
                         "(SELECT end_dt " +
                    "FROM fiscal_calendar " +
                         "WHERE fiscal_period = '?' " +
                         "AND week_number = '?' " +
                         "AND week_number <> '9' " +
                         "AND fiscal_yr = '2003') " +
          "ORDER BY actual_date, sbu ");
     getHist.setString(1, fp);
     getHist.setString(2, week_no);
     getHist.setString(3, fp);
     getHist.setString(4, week_no);
     rs = getHist.executeQuery();
     } catch (SQLException sqle) {
error = "SQLException: Update failed, possible duplicate entry.";
     throw new SQLException(error);
} else {
error = "Exception: Connection to the database was lost.";
     throw new Exception(error);
return rs;
This is in my jsp:
<%
String fp = request.getParameter("fp");
String week_no = request.getParameter("week_no");
historyInfo.connect();
ResultSet rs = historyInfo.getHistory(fp, week_no);
while (rs.next()) {
//String sum_dollar = rs.getString("sum_dollar");
%>
<%= rs.getString("sum_dollar") %>
<%
%>

Hi,
First thing U can't do this way in java. If U are executing this sort of database query, after retriving all the values, put inside Haahtable or HashMap as the application required and return it.
Otherwise execute this query at the same place where u r printing values in jsp page insted of writing it inside seperate method..It will work.
If still it's not workimg, please let me know.
Rajeh Pal

Error when returning Vector from EJB Session Bean

I am testing the EJB functionality within JDeveloper(9.0.3). I simply expanded on the tutorial that is in the documentation (departments and employees). I created a method in the stateless session bean that retrieves a Collection of employees for a department, then converts it to a Vector. When I try to return the Vector from the session bean to a sample client, I get an error indicating that the Object is NOT serializable. I know that Vector IS serializable. Why do I get this error? (The error displays on the client message log, NOT the OC4J message log). I tried dumping the Vector to System.out.println - this works fine, so I l know I'm getting data.
Here is the stack trace and errors that display:
com.evermind.server.rmi.OrionRemoteException: Error (de-)serializing object: EmployeeLocal_EntityBeanWrapper4
     java.lang.Object com.evermind.server.ejb.EJBUtils.cloneSerialize(java.lang.Object, com.evermind.server.ejb.AbstractEJBHome)
          EJBUtils.java:404
     java.lang.Object com.evermind.server.ejb.EJBUtils.cloneObject(java.lang.Object, com.evermind.server.ejb.AbstractEJBHome)
          EJBUtils.java:377
     java.lang.Object com.evermind.server.ejb.EJBUtils.cloneOneObjectInstance(java.lang.Object, com.evermind.server.ejb.AbstractEJBHome)
          EJBUtils.java:419
     java.lang.Object com.evermind.server.ejb.EJBUtils.cloneArrayList(java.util.ArrayList, com.evermind.server.ejb.AbstractEJBHome)
          EJBUtils.java:599
     java.lang.Object com.evermind.server.ejb.EJBUtils.cloneObject(java.lang.Object, com.evermind.server.ejb.AbstractEJBHome)
          EJBUtils.java:357
     java.util.Collection hrApp_StatelessSessionBeanWrapper2.getEmployeesByDepartment(java.lang.Long)
          hrApp_StatelessSessionBeanWrapper2.java:323
     java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[])
          native code
     void com.evermind.server.rmi.RMICallHandler.run(java.lang.Thread)
          RMICallHandler.java:119
     void com.evermind.server.rmi.RMICallHandler.run()
          RMICallHandler.java:48
     void EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run()
          PooledExecutor.java:803
     void java.lang.Thread.run()
          Thread.java:484
at connection to localhost/127.0.0.1 as admin
     void com.evermind.server.rmi.RMIConnection.EXCEPTION_ORIGINATES_FROM_THE_REMOTE_SERVER(java.lang.Throwable)
          RMIConnection.java:1558
     java.lang.Object com.evermind.server.rmi.RMIConnection.invokeMethod(com.evermind.server.rmi.RMIContext, long, long, java.lang.reflect.Method, java.lang.Object[])
          RMIConnection.java:1511
     java.lang.Object com.evermind.server.rmi.RemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
          RemoteInvocationHandler.java:53
     java.lang.Object com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
          RecoverableRemoteInvocationHandler.java:22
     java.lang.Object com.evermind.server.ejb.StatelessSessionRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
          StatelessSessionRemoteInvocationHandler.java:50
     java.util.Collection __Proxy1.getEmployeesByDepartment(java.lang.Long)
     javax.swing.table.DefaultTableModel hr.hrAppClientFrame.getTableModel()
          hrAppClientFrame.java:150
     void hr.hrAppClientFrame.jbInit()
          hrAppClientFrame.java:122
     void hr.hrAppClientFrame.<init>()
          hrAppClientFrame.java:58
     void hr.hrAppClientFrame.main(java.lang.String[])
          hrAppClientFrame.java:141
     Nested exception is:
java.io.NotSerializableException: EmployeeLocal_EntityBeanWrapper4
     void java.io.ObjectOutputStream.outputObject(java.lang.Object)
          ObjectOutputStream.java:1148
     void java.io.ObjectOutputStream.writeObject(java.lang.Object)
          ObjectOutputStream.java:366
     java.lang.Object com.evermind.server.ejb.EJBUtils.cloneSerialize(java.lang.Object, com.evermind.server.ejb.AbstractEJBHome)
          EJBUtils.java:390
     java.lang.Object com.evermind.server.ejb.EJBUtils.cloneObject(java.lang.Object, com.evermind.server.ejb.AbstractEJBHome)
          EJBUtils.java:377
     java.lang.Object com.evermind.server.ejb.EJBUtils.cloneOneObjectInstance(java.lang.Object, com.evermind.server.ejb.AbstractEJBHome)
          EJBUtils.java:419
     java.lang.Object com.evermind.server.ejb.EJBUtils.cloneArrayList(java.util.ArrayList, com.evermind.server.ejb.AbstractEJBHome)
          EJBUtils.java:599
     java.lang.Object com.evermind.server.ejb.EJBUtils.cloneObject(java.lang.Object, com.evermind.server.ejb.AbstractEJBHome)
          EJBUtils.java:357
     java.util.Collection hrApp_StatelessSessionBeanWrapper2.getEmployeesByDepartment(java.lang.Long)
          hrApp_StatelessSessionBeanWrapper2.java:323
     java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[])
          native code
     void com.evermind.server.rmi.RMICallHandler.run(java.lang.Thread)
          RMICallHandler.java:119
     void com.evermind.server.rmi.RMICallHandler.run()
          RMICallHandler.java:48
     void EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run()
          PooledExecutor.java:803
     void java.lang.Thread.run()
          Thread.java:484
at connection to localhost/127.0.0.1
     void com.evermind.server.rmi.OrionRemoteException.receive(java.net.InetAddress, java.lang.String)
          OrionRemoteException.java:130
     void com.evermind.server.rmi.RMIConnection.handleMethodInvocationResponse()
          RMIConnection.java:1673
     void com.evermind.server.rmi.RMIConnection.run(java.lang.Thread)
          RMIConnection.java:532
     void com.evermind.server.rmi.RMIConnection.run()
          RMIConnection.java:275
     void EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run()
          PooledExecutor.java:797
     void java.lang.Thread.run()
          Thread.java:484
Any ideas?
Thanks

I would suggest opening a case with [email protected] FWIW, I recall seeing
          something like this in WLS 6.0. I believe it is fixed in WLS 6.1
          -- Rob
          Chris Dupuy wrote:
          > Btw, this occurs when I create an stateful session bean that ends up
          > throwing an exception and setRollbackOnly() is called. From that point
          > forward, my logs fill with this message.
          >
          > Chris
          >
          > "Chris Dupuy" <[email protected]> wrote in message
          > news:[email protected]..
          > > anyone know what this means, and what you can do about it?
          > >
          > >
          > > <Error> <ConnectionManager> <atossd03> <cbeyondServer> <ExecuteThread:
          > '14'
          > > for queue: 'd
          > > efault'> <> <> <000000> <Closing:
          > 'weblogic.rjvm.t3.T3JVMConnection@488831'
          > > because of: 'Server received a message over an uniniti
          > > alized connection: 'JVMMessage from: 'null' to:
          > >
          > '5825313123619479267S:10.6.6.40:[8000,8000,8001,8001,8000,8001,-1]:cbeyond:c
          > > beyond
          > > Server' cmd: 'CMD_REQUEST', QOS: '101', responseId: '2', invokableId: '1',
          > > flags: 'JVMIDs Not Sent, TX Context Not Sent', abbrev o
          > > ffset: '204'''>
          > >
          > >
          > >

Returning ResultSet data

i want my class to return data to another class. I know i cant return a ResultSet because my connection closes. Can i return some collection similar to a ResultSet ( something 2 dimensional). Can i return metadata from this class?
thanx

A typical solution is to return an ArrayList (or some other datatype) that contains several objects, each containing the data from the row. For example, if I wanted to return a username/password combination, you can create a User class that simply holds those two values, then each iteration through your ResultSet, create a new object, put the two values in it, and stick it in your ArrayList.
This is probably the most effective way, since any datastructure is generally intended to handle data of a certain type, and since data from your database is most likely varying in types, creating one two-dimensional datastructure is probably not going to be as effective.

Returning ResultSets to jsp

Hi,
I'm using a javabean that returns a resultset from oracle and i need that resultset to execute another query so i can return the data to a jsp. My problem is it will only execute through a while loop once as i have passed it to a String. Does anyone have any idea how i could go about this? So far I've been using while loops eg.
     result = select.executeQuery("select * from score where stu_score = 10 and level_id = 1");
          while(result.next())
String s = result.getString("stu_id");
System.out.println(s);
result = select.executeQuery("Select stu_name from Student where stu_id = '"+s+"'");
while(result.next())
     String r = result.getString("stu_name");
     System.out.println(r);
This will return one stu_id and one stu_name. Any ideas?

Hi,
You are getting results from the database and storing them in result. Inside your outermost while loop you are overwriting the same object i.e. result, by saying
result = select.executeQuery("Select stu_name from Student where stu_id = '"+s+"'");
That is why you only get one stu_id and one stu_name. Outside the first while loop, declare another ResultSet object, call it result2, and use that one inside.
However, I strongly recommend not to run such code in a jsp. Do this in a servlet, and set your results that you get through the resultsets in a data transfer object, store it in the request or session, and then get it in the jsp. Also, remeber to close your resultset, statment, and connection objects, otherwise you will suffer from the open cursors problem - eventually! And above all, that is the right way of doing stuff.
Hope this helps.

How to return data from Ejb as collection to Front End application.

Hi,
I am creating a J2ee application. Here i am accessing BAPIs using stateless session bean through JCO connection. Now the BAPI is returning a return Table and return Structure to the EJB.
I have coded the following code in one of the Ejb Method as follows:
JCO.Table returnTable = null;
JCO.Structure returnStructure = null;
JCO.ParameterList paramList = siteBAPI.getExportParameterList();
JCO.ParameterList paramList2 = siteBAPI.getTableParameterList();
returnTable = paramList2.getTable("SITE_SUBSITE_INSTL");
returnStructure = paramList.getStructure("BAPIRET2");
Now i want to sent this data( returnTable & returnStructure) to front end application where front end developer accessing this returned data using Jsp.
My scenario is that , first i want to convert this returnTable & returnStructure in a single collection and then sent this collection to Front end.
My aim is that , the front end the application should not receive the Data, using JCO.table Variable but as a single Collection.
I am using NWDI-2004s sps10.
i need urgent help on this issue and i would really appreciate if somebody can put the answer with some sample code on how to return the data as Collection.

if you want to return a result, then you probably shouldn't be using a message bean. message beans for for asynchronous tasks. session beans for for synchronous tasks. thus it would make much more sense to have your jsp call the session bean directly.

Return ResultSet via RMI

Hello all,
I understand that it is not possible to return a ResultSet via RMI, correct?
I have a query that I want to use its recordset and this recordset would then be used as an argument for my TableModel to create the data.
How can I use a vector or arrayList to transfer the ResultSet via RMI?
Here's my secenario:
==== View.java ==============
ResultSet rsData = getModel().viewRecord(sortString);
myTable.setModel(getModel().getMyTableModel(rsData));
myTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
==== Model.java ==============
public ResultSet viewRecord(String query) {
try {
return getDBStatement().executeQuery( query ); <--- instead of this..
what do I have to do here to return it as a Vector or arrayList
catch ( SQLException e ) {
e.printStackTrace();
return null;
How do I use RMI to get the record set back and read it for my View?
Thanks,
Christopher

Hello lgurevich ,
Please forgive me my crazy questions as I'm just starting to learn and implement about RMI.
Can you or anyone else provide / illustrate to me some specific examples as to how I could do this.
Here's my logic:
View - Model (the model is the remote Implementator)
====== MyView.java ===========
String myQuery = "SELECT field1, field2, blah, blah ........ ";
ResultSet rs = getMyModel().viewRecord(myQuery);
myTable.setModel(getMyModel().getMyTableModel(rs));
myTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
============================
======= MyModel.java ===========
public ResultSet viewRecord(String query) {
try {
return getModelDBStatement().executeQuery( query );
catch ( SQLException e ) {
e.printStackTrace();
return null;
} // end of viewRecord()
public MyTableModel getMyTableModel(ResultSet r)
throws SQLException {
     // Create and return my MyTableModel for the ResultSet
     return new MyTableModel(r);
============================
======== MyTableModel.java ===========
public class MyTableModel
extends AbstractTableModel {
private ResultSet results;
Vector totalrows = new Vector();
public MyTableModel(ResultSet rs) throws SQLException {
this.results = rs;
ResultSetMetaData rsmd = rs.getMetaData();
int columns = rsmd.getColumnCount();
headers = new String[columns];
for (int i = 0; i < columns; i++) {
headers[i] = rsmd.getColumnName(i+1);
/* ** Create a list of the column data */
while (rs.next())
String[] record = new String[columns];
for (int i = 0; i < columns; i++) {
     record[i] = rs.getString(i+1);
totalrows.addElement( record );
} // end of MyTableModel class
============================
So basically, what I'm asking is how do I implement the CachedRowSet to replace the logic of what I have here?
That is:
1. To send the query from my view to my model
2. Model processes the query
3. Model creates the resultset
4. Model puts the resultset in the CachedRowSet?
5. Model sends the CachedRowSet? back to the View.
6. The View then deserializes? the CachedRowSet? back to a resultset object.
7. Should I even need to do step 6 considering, I have to send it back to the Model immediately so i could set my TableModel (ie. myTable.setModel(getMyModel().getMyTableModel(rs)); ).
Any help is greatly appreciated.
Thanks,
Christopher

Returning resultset to a list

I am trying to return my resultset to a List of Integers, but the example i am following uses a list of doubles. I have been getting on ok with with this untill i came to this point
while (rs.next()) { int result = rs.getInteger(1); topTimes.add(result); }
The getInteger method requires a system property as a parameter. What is a system property?

I actually made a silly error, which is why i was being returned with the wrong values. I had the result field set to text instead of number. Thats just about me done with this problem now, after about 2 months! The final thing is one error i am being returned on the command line after i receive the results. I have done everything in one method as i have other quiries in this class.
public void getFastest()
String SELECT_TOP_TIMES =
"select TOP 3 r.result " +
"from tblResults as r " +
"where r.Event_ID = " +
"(select e.ID " +
"from tblEvent as e " +
"where e.Event_Name = '100M Run') " +
"and r.Round_ID = " +
"(select ro.ID " +
"from tblRound as ro " +
"where ro.Round_Number = 'Round_1') " +
"order by r.result";
PreparedStatement ps = null;
ResultSet rs = null;
List<Integer> topTimes = new ArrayList<Integer>();
try
con = DatabaseUtils.connect(DRIVER, URL);
ps = con.prepareStatement(SELECT_TOP_TIMES);
rs = ps.executeQuery();
while (rs.next())
int result = rs.getInt(1);
topTimes.add(result);
System.out.println(topTimes);
catch(Exception e)
System.out.println(e);
DatabaseUtils.rollback(con);
e.printStackTrace();
finally
DatabaseUtils.close(ps);
DatabaseUtils.close(rs);
DatabaseUtils.close(con);
}But with it set like this, i get returned this message in my command prompt
[3, 4, 32]
java.sql.SQLException: ResultSet is closed
        at sun.jdbc.odbc.JdbcOdbcResultSet.checkOpen(JdbcOdbcResultSet.java:6646
        at sun.jdbc.odbc.JdbcOdbcResultSet.clearWarnings(JdbcOdbcResultSet.java:
1765)
        at sun.jdbc.odbc.JdbcOdbcResultSet.close(JdbcOdbcResultSet.java:1468)
        at DatabaseUtils.close(DatabaseUtils.java:41)
        at DatabaseSQL.getFastest(DatabaseSQL.java:143)
        at Meet.exit_actionPerformed(Meet.java:440)
        at Meet.access$600(Meet.java:9)
        at Meet$7.actionPerformed(Meet.java:183)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:19
95)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.jav
a:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel
.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonL
istener.java:236)
        at java.awt.Component.processMouseEvent(Component.java:6041)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
        at java.awt.Component.processEvent(Component.java:5806)
        at java.awt.Container.processEvent(Container.java:2058)
        at java.awt.Component.dispatchEventImpl(Component.java:4413)
        at java.awt.Container.dispatchEventImpl(Container.java:2116)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3986)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3916)
        at java.awt.Container.dispatchEventImpl(Container.java:2102)
        at java.awt.Window.dispatchEventImpl(Window.java:2440)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThre
ad.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.
java:183)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.
java:177)
        at java.awt.Dialog$1.run(Dialog.java:1045)
        at java.awt.Dialog$3.run(Dialog.java:1097)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.awt.Dialog.show(Dialog.java:1095)
        at java.awt.Component.show(Component.java:1422)
        at java.awt.Component.setVisible(Component.java:1375)
        at java.awt.Window.setVisible(Window.java:806)
        at java.awt.Dialog.setVisible(Dialog.java:985)
        at CreateAtlDatabase.CreateAtlDatabase_actionPerformed(CreateAtlDatabase
.java:110)
        at CreateAtlDatabase.access$000(CreateAtlDatabase.java:8)
        at CreateAtlDatabase$1.actionPerformed(CreateAtlDatabase.java:67)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:19
95)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.jav
a:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel
.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonL
istener.java:236)
        at java.awt.Component.processMouseEvent(Component.java:6041)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
        at java.awt.Component.processEvent(Component.java:5806)
        at java.awt.Container.processEvent(Container.java:2058)
        at java.awt.Component.dispatchEventImpl(Component.java:4413)
        at java.awt.Container.dispatchEventImpl(Container.java:2116)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3986)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3916)
        at java.awt.Container.dispatchEventImpl(Container.java:2102)
        at java.awt.Window.dispatchEventImpl(Window.java:2440)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThre
ad.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.
java:183)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThre
ad.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)Do i need to set up the List in its own method and then pass the resultset to this method?

Returning Resultsets in EJB

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