MDB_PutBid


1   package edu.rice.rubis.beans;
2   
3   import java.rmi.RemoteException  ;
4   import javax.ejb.MessageDrivenBean  ;
5   import javax.ejb.MessageDrivenContext  ;
6   import javax.ejb.EJBException  ;
7   import javax.jms.*;
8   import javax.naming.Context  ;
9   import javax.naming.InitialContext  ;
10  import javax.rmi.PortableRemoteObject  ;
11  import javax.sql.DataSource  ;
12  import java.io.Serializable  ;
13  
14  /**
15   * This is a stateless session bean used to build the html form to put a bid.
16   *  
17   * @author <a HREF="mailto:cecchet@rice.edu">Emmanuel Cecchet</a> and <a HREF="mailto:julie.marguerite@inrialpes.fr">Julie Marguerite</a>
18   * @version 1.1
19   */
20  
21  public class MDB_PutBid implements MessageDrivenBean  , MessageListener 
22  {
23    private DataSource   dataSource;
24    private MessageDrivenContext   messageDrivenContext;
25    private TopicConnectionFactory connectionFactory;
26    private TopicConnection connection;
27    private Topic topic;
28    private TopicSession session;
29    private TopicPublisher replier;
30    private Context   initialContext = null;
31  
32  
33    public MDB_PutBid()
34    {
35  
36    }
37  
38    public void onMessage(Message message)
39    {
40      try
41      {
42        MapMessage request = (MapMessage)message;
43        String   correlationID = request.getJMSCorrelationID();
44        int itemId = request.getInt("itemId");
45        String   username = request.getString("username");
46        String   password = request.getString("password");  
47  
48          // Retrieve the connection factory
49          connectionFactory = (TopicConnectionFactory) initialContext.lookup(BeanConfig.TopicConnectionFactoryName);
50  
51        // get the post comment form
52        String   html = getBiddingForm(itemId, username, password);
53  
54        // send the reply
55        TemporaryTopic temporaryTopic = (TemporaryTopic) request.getJMSReplyTo();
56        if (temporaryTopic != null)
57        {
58          // create a connection
59          connection = connectionFactory.createTopicConnection();
60          // create a session: no transaction, auto ack
61          session = connection.createTopicSession(false, Session.AUTO_ACKNOWLEDGE);
62          TextMessage reply = session.createTextMessage();
63          reply.setJMSCorrelationID(correlationID);
64          reply.setText(html);
65          replier = session.createPublisher(null); // unidentified publisher
66          connection.start();
67          replier.publish(temporaryTopic, reply);
68          replier.close();
69          session.close();
70          connection.stop();
71          connection.close();
72        }
73      }
74      catch (Exception   e)
75      {
76        throw new EJBException  ("Message traitment failed for MDB_PutBid: " +e);
77      }
78    }
79  
80    /**
81     * Authenticate the user and get the information to build the html form.
82     *
83     * @return a string in html format
84     * @since 1.1
85     */
86    public String   getBiddingForm(int itemId, String   username, String   password) throws RemoteException   
87    {
88      int userId = -1;
89      String   html = "";
90  
91      // Authenticate the user who want to bid
92        if ((username != null && !username.equals("")) || (password != null && !password.equals("")))
93        {
94          TopicConnection authConnection;
95          TopicSession authSession;
96          Topic authTopic;
97          try 
98          {
99            // create a connection
100           authConnection = connectionFactory.createTopicConnection();
101           // lookup the destination
102           authTopic = (Topic) initialContext.lookup(BeanConfig.PrefixTopicName+"topicAuth");
103           // create a session
104           authSession  = authConnection.createTopicSession(false, Session.AUTO_ACKNOWLEDGE); // no transaction and auto ack
105         } 
106         catch (Exception   e)
107         {
108           throw new EJBException  ("Cannot connect to message bean MDB_Auth : " +e+"<br>");
109         }
110         try 
111         {
112           // create a requestor to receive the reply
113           TopicRequestor requestor = new TopicRequestor(authSession, authTopic);
114           // create a message
115           MapMessage m = authSession.createMapMessage();
116           // set parameters
117           m.setStringProperty("nickname", username);
118           m.setStringProperty("password", password);
119           m.setJMSCorrelationID("auth");
120           // send the message and receive the reply
121           authConnection.start(); // allows message to be delivered (default is connection stopped)
122           MapMessage authReply = (MapMessage)requestor.request(m);
123           authConnection.stop();
124           // read the reply
125           userId = authReply.getInt("userId");
126           // close connection and session
127           requestor.close(); // also close the session
128           authConnection.close();
129         } 
130         catch (Exception   e)
131         {
132           throw new EJBException  ("user authentication failed: " +e+"<br>");
133         }
134         if (userId == -1)
135         {
136            html = "You don't have an account on RUBiS!<br>You have to register first.<br>";
137            return html;
138         }
139       }
140 
141         TopicConnection itemConnection;
142         TopicSession itemSession;
143         Topic itemTopic;
144         try 
145         {
146           // create a connection
147           itemConnection = connectionFactory.createTopicConnection();
148           // lookup the destination
149           itemTopic = (Topic) initialContext.lookup(BeanConfig.PrefixTopicName+"topicViewItem");
150           // create a session
151           itemSession  = itemConnection.createTopicSession(false, Session.AUTO_ACKNOWLEDGE); // no transaction and auto ack
152         } 
153         catch (Exception   e)
154         {
155           throw new EJBException  ("Cannot connect to message bean MDB_ViewItem : " +e+"<br>");
156         }
157         try 
158         {
159           // create a requestor to receive the reply
160           TopicRequestor requestor = new TopicRequestor(itemSession, itemTopic);
161           // create a message
162           MapMessage m = itemSession.createMapMessage();
163           // set parameters
164           m.setInt("itemId", itemId);
165           m.setInt("userId", userId);
166           m.setJMSCorrelationID("viewItem");
167           // send the message and receive the reply
168           itemConnection.start(); // allows message to be delivered (default is connection stopped)
169           TextMessage itemReply = (TextMessage)requestor.request(m);
170           itemConnection.stop();
171           // read the reply
172           html = itemReply.getText();
173           // close connection and session
174           requestor.close(); // also close the session
175           itemConnection.close();
176         } 
177         catch (Exception   e)
178         {
179           throw new EJBException  ("Exception getting the item information: " +e+"<br>");
180         }
181         return html;
182   }
183                    
184   // ======================== EJB related methods ============================
185 
186   /** 
187    * Set the associated context. The container call this method
188    * after the instance creation. 
189    * The enterprise Bean instance should store the reference to the context
190    * object in an instance variable. 
191    * This method is called with no transaction context.
192    *
193    * @param MessageDrivenContext A MessageDrivenContext interface for the instance.
194    * @throws EJBException Thrown by the method to indicate a failure caused by
195    * a system-level error.
196    */
197   public void setMessageDrivenContext(MessageDrivenContext   ctx)
198   {
199     messageDrivenContext = ctx;
200     if (dataSource == null)
201     {
202       // Finds DataSource from JNDI
203       try
204       {
205         initialContext = new InitialContext  (); 
206         dataSource = (DataSource  )initialContext.lookup("java:comp/env/jdbc/rubis");
207       }
208       catch (Exception   e) 
209       {
210         throw new EJBException  ("Cannot get JNDI InitialContext");
211       }
212     }
213   }
214 
215   /**
216    * The Message driven  bean must define an ejbCreate methods with no args.
217    *
218    */
219   public void ejbCreate() 
220   {
221 
222   }
223  
224   /**
225    * A container invokes this method before it ends the life of the message-driven object. 
226    * This happens when a container decides to terminate the message-driven object. 
227    *
228    * This method is called with no transaction context. 
229    *
230    * @throws EJBException Thrown by the method to indicate a failure caused by
231    * a system-level error.
232    */
233   public void ejbRemove() {}
234 
235 
236 
237 }
238
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