//===================START_PROLOG======================================
//
// 5630-A23, 5630-A22,
// (C) COPYRIGHT International Business Machines Corp. 2002
// All Rights Reserved
// Licensed Materials - Property of IBM
// US Government Users Restricted Rights - Use, duplication or
// disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
//
// IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
// ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL, INDIRECT OR
// CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
// USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE
// OR PERFORMANCE OF THIS SOFTWARE.
//
//===================END_PROLOG========================================
package WebSphereSamples.ConnPool;
import java.rmi.RemoteException;
import java.util.*;
import java.sql.*;
import javax.sql.*;
import javax.ejb.*;
import javax.naming.*;
import javax.transaction.*;
/*************************************************************************************
* This bean is designed to demonstrate Database Connections in a * Bean-Managed Transaction Session Bean. Its transaction attribute * should be set to TX_BEANMANAGED.
***************************************************************************************/
public class ShowEmployeesBMTBean implements SessionBean {
private javax.ejb.SessionContext mySessionCtx = null;
final static long serialVersionUID = 3206093459760846163L;
private javax.sql.DataSource ds;
private javax.transaction.UserTransaction userTran;
//************************************************************************************
//* ejbActivate calls the getDS method, which makes the JNDI lookup for the DataSource
//* Because the DataSource lookup is in a separate method, we can also invoke it from
//* the getEmployees method in the case where the DataSource field is null.
//************************************************************************************
public void ejbActivate() throws java.rmi.RemoteException {
getDS();
}
/**
* ejbCreate method
* @exception javax.ejb.CreateException
* @exception java.rmi.RemoteException
*/
public void ejbCreate() throws javax.ejb.CreateException, java.rmi.RemoteException {}
/**
* ejbPassivate method
* @exception java.rmi.RemoteException
*/
public void ejbPassivate() throws java.rmi.RemoteException {}
/**
* ejbRemove method
* @exception java.rmi.RemoteException
*/
public void ejbRemove() throws java.rmi.RemoteException {}
//************************************************************************************
//* The getEmployees method runs the database query to retrieve the employees.
//* The getDS method is only called if the DataSource or userTran variables are null.
//* If a StaleConnectionException occurs, the bean retries the transaction 5 times,
//* then throws an EJBException. *
//************************************************************************************
public Vector getEmployees() throws EJBException {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
Vector employeeList = new Vector();
// Set retryCount to the number of times you would like to retry after a
//StaleConnectionException"
int retryCount = 5;
// If the Database code processes successfully, we will set error = false
boolean error = true;
if (ds == null || userTran == null) getDS();
do {
try {
//try/catch block for UserTransaction work
//Begin the transaction
userTran.begin();
try {
//try/catch block for database work
//Get a Connection object conn using the DataSource factory.
conn = ds.getConnection();
// Run DB query using standard JDBC coding.
stmt = conn.createStatement();
String query = "Select FirstNme, MidInit, LastName " +
"from Employee ORDER BY LastName";
rs = stmt.executeQuery(query);
while (rs.next()) {
employeeList.addElement(rs.getString(3) + ", " + rs.getString(1) + " " + rs.getString(2));
}
//Set error to false, as all database operations are successfully completed
error = false;
}
catch (com.ibm.websphere.ce.cm.StaleConnectionException se) {
// This exception indicates that the connection to the database is no longer valid.
// Rollback the transaction, and throw an exception to the client indicating they
// can retry the transaction if desired.
System.out.println("Stale Connection Exception during get connection or process SQL: " + se.getMessage());
userTran.rollback();
if (--retryCount == 0) {
//If we have already retried the requested number of times, throw an EJBException.
throw new EJBException("Transaction Failure: " + se.toString());
}
else {
System.out.println("Retrying transaction, retryCount = " + retryCount);
}
}
catch (com.ibm.ejs.cm.pool.ConnectionWaitTimeoutException cw) {
// This exception is thrown if a connection can not be obtained from the
// pool within a configurable amount of time. Frequent occurrences of
// this exception indicate an incorrectly tuned connection pool
System.out.println("Connection Wait Timeout Exception during get connection or process SQL: " + cw.getMessage());
userTran.rollback();
throw new EJBException("Transaction failure: " + cw.getMessage());
}
catch (SQLException sq) {
// This catch handles all other SQL Exceptions
System.out.println("SQL Exception during get connection or process SQL: " +
sq.getMessage());
userTran.rollback();
throw new EJBException("Transaction failure: " + sq.getMessage());
}
finally {
// Always close the connection in a finally statement to ensure proper
// closure in all cases. Closing the connection does not close and
// actual connection, but releases it back to the pool for reuse.
if (rs != null) {
try {
rs.close();
}
catch Exception(e) {
System.out.println("Close Resultset Exception: " + e.getMessage());
}
}
if (stmt != null) {
try {
stmt.close();
}
catch Exception(e) {
System.out.println("Close Statement Exception: " + e.getMessage());
}
}
if (conn != null) {
try {
conn.close();
}
catch Exception(e) {
System.out.println("Close connection exception: " + e.getMessage());
}
}
}
if (!error) {
//Database work completed successfully, commit the transaction
userTran.commit();
}
//Catch UserTransaction exceptions
}
catch (NotSupportedException nse) {
//Thrown by UserTransaction begin method if the thread is already associated with a
//transaction and the Transaction Manager implementation does not support nested //transactions.
System.out.println("NotSupportedException on User Transaction begin: " +
nse.getMessage());
throw new EJBException("Transaction failure: " + nse.getMessage());
}
catch (RollbackException re) {
//Thrown to indicate that the transaction has been rolled back rather than committed.
System.out.println("User Transaction Rolled back! " + re.getMessage());
throw new EJBException("Transaction failure: " + re.getMessage());
}
catch (SystemException se) {
//Thrown if the transaction manager encounters an unexpected error condition
System.out.println("SystemException in User Transaction: "+ se.getMessage());
throw new EJBException("Transaction failure: " + se.getMessage());
}
catch Exception(e) {
//Handle any generic or unexpected Exceptions
System.out.println("Exception in User Transaction: " + e.getMessage());
throw new EJBException("Transaction failure: " + e.getMessage());
}
}
while (error);
return employeeList;
}
/**
* getSessionContext method comment
* @return javax.ejb.SessionContext
*/
public javax.ejb.SessionContext getSessionContext() {
return mySessionCtx;
}
//************************************************************************************
//* The getDS method performs the JNDI lookup for the DataSource.
//* This method is called from ejbActivate, and from getEmployees if the DataSource
//* object is null.
//************************************************************************************
private void getDS() {
try {
// Note the new Initial Context Factory interface available in WebSphere 4.0
Hashtable parms = new Hashtable();
parms.put(Context.INITIAL_CONTEXT_FACTORY,
"com.ibm.websphere.naming.WsnInitialContextFactory");
InitialContext ctx = new InitialContext(parms);
// Perform a naming service lookup to get the DataSource object.
ds = (DataSource)ctx.lookup("java:comp/env/jdbc/SampleDB");
//Create the UserTransaction object
userTran = mySessionCtx.getUserTransaction();
}
catch Exception(e) {
System.out.println("Naming service exception: " + e.getMessage());
e.printStackTrace();
}
}
/**
* setSessionContext method
* @param ctx javax.ejb.SessionContext
* @exception java.rmi.RemoteException
*/
public void setSessionContext(javax.ejb.SessionContext ctx) throws java.rmi.RemoteException {
mySessionCtx = ctx;
}
}
//===================START_PROLOG======================================
//
// 5630-A23, 5630-A22,
// (C) COPYRIGHT International Business Machines Corp. 2002
// All Rights Reserved
// Licensed Materials - Property of IBM
// US Government Users Restricted Rights - Use, duplication or
// disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
//
// IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
// ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL, INDIRECT OR
// CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
// USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE
// OR PERFORMANCE OF THIS SOFTWARE.
//
//===================END_PROLOG========================================
package WebSphereSamples.ConnPool;
/**
* This is a Home interface for the Session Bean
*/
public interface ShowEmployeesBMTHome extends javax.ejb.EJBHome {
/**
* create method for a session bean
* @return WebSphereSamples.ConnPool.ShowEmployeesBMT
* @exception javax.ejb.CreateException
* @exception java.rmi.RemoteException
*/
WebSphereSamples.ConnPool.ShowEmployeesBMT create() throws javax.ejb.CreateException, java.rmi.RemoteException;
}
//===================START_PROLOG======================================
//
// 5630-A23, 5630-A22,
// (C) COPYRIGHT International Business Machines Corp. 2002
// All Rights Reserved
// Licensed Materials - Property of IBM
// US Government Users Restricted Rights - Use, duplication or
// disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
//
// IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
// ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL, INDIRECT OR
// CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
// USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE
// OR PERFORMANCE OF THIS SOFTWARE.
//
//===================END_PROLOG========================================
package WebSphereSamples.ConnPool;
/**
* This is an Enterprise Java Bean Remote Interface
*/
public interface ShowEmployeesBMT extends javax.ejb.EJBObject {
/**
*
* @return java.util.Vector
*/
java.util.Vector getEmployees() throws java.rmi.RemoteException, javax.ejb.EJBException;
}