private void setupMessageListener()
throws javax.jms.JMSException, javax.naming.NamingException, Exception {
InitialContext ctx = new InitialContext();
QueueConnectionFactory factory = (QueueConnectionFactory) ctx.lookup("jms/taskQueueFactory");
connection = factory.createQueueConnection();
session = connection.createQueueSession(false, Session.CLIENT_ACKNOWLEDGE);
Queue queue = (Queue) ctx.lookup("jms/taskQueue");
receiver = session.createConsumer(queue);
connection.start();
ctx.close();
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
out.println("<html><head></head><body>");
try {
// Gather necessary JMS resources
Context ctx = new InitialContext();
ConnectionFactory cf = (ConnectionFactory) ctx.lookup("jms/myConnectionFactory");
Connection con = cf.createConnection();
con.start(); // don't forget to start the connection
QueueSession session = (QueueSession) con.createSession(false, Session.AUTO_ACKNOWLEDGE);
// The PITsnapshot Queue is used for responses from the Players to this serverlet
Queue q = (Queue) ctx.lookup("jms/PITsnapshot");
MessageConsumer reader = session.createConsumer(q);
/*
* Throw out old PITsnapshot messages that may have been left from past
* snapshots that did not complete (because of some error).
*/
ObjectMessage m = null;
while ((m = (ObjectMessage) reader.receiveNoWait()) != null) {
System.out.println("Found an orphaned PITsnapshot message");
}
// Initialize the snapshot my sending a marker to a Player
sendInitSnapshot();
/*
* Receive the snapshot messages from all Players.
* Each snapshot is a HahsMap. Put them into an array of HashMaps *
*/
HashMap state[] = new HashMap[numPlayers + 1];
int stateResponses = 0;
int failures = 0;
while (stateResponses < numPlayers) {
if ((m = (ObjectMessage) reader.receive(1000)) == null) {
if (++failures > 10) {
System.out.println("Not all players reported, giving up after " + stateResponses);
break;
}
continue;
}
state[stateResponses++] = (HashMap) m.getObject();
}
/*
* For each commodity, sum the number of them reported from
* each Player. Store these into a two dimensional table
* that will then be used to generate the report back to the user.
*/
String commodity[] = {"rice", "gold", "oil"};
int total[][] = new int[numPlayers][commodity.length];
for (int c = 0; c < commodity.length; c++) {
for (int p = 0; p < stateResponses; p++) {
try {
Integer ccount = (Integer) state[p].get(commodity[c]);
if (ccount == null) {
total[p][c] = 0;
} else {
total[p][c] = (Integer) ccount.intValue();
}
} catch (Exception e) {
System.out.println("Servlet threw exception " + e);
}
}
}
/*
* Now turn the table of commodities, and the state from each Player
* into a response to the user.
*/
for (int c = 0; c < commodity.length; c++) {
int ctotal = 0;
out.print("<h2>Commodity: " + commodity[c] + "</h2>");
out.print("<table border='1'><tr><th>Player</th><th>Quantity</th></tr>");
for (int p = 0; p < stateResponses; p++) {
out.print("<tr><td>" + p + "</td><td>" + total[p][c] + "</td></tr>");
ctotal += total[p][c];
}
out.print("<tr><td><b>Total</b></td><td>" + ctotal + "</td></tr>");
out.print("</table></br></br>");
}
// Close the connection
con.close();
out.println("</BODY></HTML>");
} catch (Exception e) {
System.out.println("Servlet threw exception " + e);
} finally {
out.println("</body></html>");
out.close();
}
}