package edu.rice.rubis.beans;
import java.rmi.RemoteException;
import javax.ejb.MessageDrivenBean;
import javax.ejb.MessageDrivenContext;
import javax.ejb.EJBException;
import javax.jms.*;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.rmi.PortableRemoteObject;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.io.Serializable;
/**
* This is a stateless session bean used get the bid history of an item.
*
* @author Emmanuel Cecchet and Julie Marguerite
* @version 1.1
*/
public class MDB_ViewBidHistory implements MessageDrivenBean, MessageListener
{
private DataSource dataSource;
private MessageDrivenContext messageDrivenContext;
private TopicConnectionFactory connectionFactory;
private TopicConnection connection;
private Topic topic;
private TopicSession session;
private TopicPublisher replier;
private Context initialContext = null;
public MDB_ViewBidHistory()
{
}
public void onMessage(Message message)
{
try
{
MapMessage request = (MapMessage)message;
String correlationID = request.getJMSCorrelationID();
int itemId = request.getInt("itemId");
// Retrieve the connection factory
connectionFactory = (TopicConnectionFactory) initialContext.lookup(BeanConfig.TopicConnectionFactoryName);
// get the bids history
String html = getBidHistory(itemId);
// send the reply
TemporaryTopic temporaryTopic = (TemporaryTopic) request.getJMSReplyTo();
if (temporaryTopic != null)
{
// create a connection
connection = connectionFactory.createTopicConnection();
// create a session: no transaction, auto ack
session = connection.createTopicSession(false, Session.AUTO_ACKNOWLEDGE);
TextMessage reply = session.createTextMessage();
reply.setJMSCorrelationID(correlationID);
reply.setText(html);
replier = session.createPublisher(null); // unidentified publisher
connection.start();
replier.publish(temporaryTopic, reply);
replier.close();
session.close();
connection.stop();
connection.close();
}
}
catch (Exception e)
{
throw new EJBException("Message traitment failed for MDB_ViewBidHistory: " +e);
}
}
/**
* Get the list of bids related to a specific item.
*
* @return a string in html format
* @since 1.1
*/
public String getBidHistory(int itemId) throws RemoteException
{
StringBuffer html = null;
PreparedStatement stmt = null;
ResultSet rs = null;
Connection conn = null;
String date = null, bidderName = null, itemName = null;
float bid = 0;
int userId = -1;
// get the item
try
{
conn = dataSource.getConnection();
stmt = conn.prepareStatement("SELECT name FROM items WHERE id=?");
stmt.setInt(1, itemId);
rs = stmt.executeQuery();
}
catch (Exception e)
{
try
{
if (stmt != null) stmt.close();
if (conn != null) conn.close();
}
catch (Exception ignore)
{
}
throw new RemoteException("Failed to execute Query for item in items table: " +e);
}
try
{
if (!rs.first())
{
stmt.close();
stmt = conn.prepareStatement("SELECT name FROM old_items WHERE id=?");
stmt.setInt(1, itemId);
rs = stmt.executeQuery();
}
}
catch (Exception e)
{
try
{
if (stmt != null) stmt.close();
if (conn != null) conn.close();
}
catch (Exception ignore)
{
}
throw new RemoteException("Failed to execute Query for item in old_items table: " +e);
}
try
{
if ((rs == null) || (!rs.first())) // This item does not exist
{
stmt.close();
conn.close();
return "";
}
else
{
itemName = rs.getString("name");
html = new StringBuffer("Bid History for "+itemName+"
");
}
stmt.close();
}
catch (Exception e)
{
try
{
if (conn != null) conn.close();
}
catch (Exception ignore)
{
}
throw new RemoteException("This item does not exist (got exception: " +e+")
");
}
// Get the list of the user's last bids
try
{
stmt = conn.prepareStatement("SELECT * FROM bids WHERE item_id=? ORDER BY date DESC");
stmt.setInt(1, itemId);
rs = stmt.executeQuery();
if (!rs.first())
{
stmt.close();
conn.close();
return html.append("There is no bid corresponding to this item.
").toString();
}
}
catch (SQLException e)
{
try
{
if (stmt != null) stmt.close();
if (conn != null) conn.close();
}
catch (Exception ignore)
{
}
throw new RemoteException("Exception getting bids list: " +e+"
");
}
PreparedStatement userStmt = null;
try
{
html.append(printBidHistoryHeader());
userStmt = conn.prepareStatement("SELECT nickname FROM users WHERE id=?");
ResultSet urs = null;
do
{
// Get the bids
date = rs.getString("date");
bid = rs.getFloat("bid");
userId = rs.getInt("user_id");
userStmt.setInt(1, userId);
urs = userStmt.executeQuery();
if (urs.first())
bidderName = urs.getString("nickname");
html.append(printBidHistory(userId, bidderName, bid, date));
}
while(rs.next());
html.append(printBidHistoryFooter());
userStmt.close();
stmt.close();
conn.close();
}
catch (SQLException e)
{
try
{
if (userStmt != null) userStmt.close();
if (stmt != null) stmt.close();
if (conn != null) conn.close();
}
catch (Exception ignore)
{
}
throw new RemoteException("Exception getting bid: " +e+"
");
}
return html.toString();
}
/**
* Display bid history information as an HTML table row
*
* @return a String containing HTML code
* @exception RemoteException if an error occurs
* @since 1.0
*/
public String printBidHistory(int userId, String bidderName, float bid, String date) throws RemoteException
{
return "| "+bidderName+" | "+bid+" | "+date+"\n";
}
/**
* Bids list header printed function
*
* @return a string in html format
* @since 1.1
*/
public String printBidHistoryHeader()
{
return "\n\n"+
"| User ID | Bid amount | Date of bid\n |
|---|
\n";
}
/**
* Bids list footer printed function
*
* @return a string in html format
* @since 1.1
*/
public String printBidHistoryFooter()
{
return " \n";
}
// ======================== EJB related methods ============================
/**
* Set the associated context. The container call this method
* after the instance creation.
* The enterprise Bean instance should store the reference to the context
* object in an instance variable.
* This method is called with no transaction context.
*
* @param MessageDrivenContext A MessageDrivenContext interface for the instance.
* @throws EJBException Thrown by the method to indicate a failure caused by
* a system-level error.
*/
public void setMessageDrivenContext(MessageDrivenContext ctx)
{
messageDrivenContext = ctx;
if (dataSource == null)
{
// Finds DataSource from JNDI
try
{
initialContext = new InitialContext();
dataSource = (DataSource)initialContext.lookup("java:comp/env/jdbc/rubis");
}
catch (Exception e)
{
throw new EJBException("Cannot get JNDI InitialContext");
}
}
}
/**
* The Message driven bean must define an ejbCreate methods with no args.
*
*/
public void ejbCreate()
{
}
/**
* A container invokes this method before it ends the life of the message-driven object.
* This happens when a container decides to terminate the message-driven object.
*
* This method is called with no transaction context.
*
* @throws EJBException Thrown by the method to indicate a failure caused by
* a system-level error.
*/
public void ejbRemove() {}
}
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