Retailerpublic class Retailer extends Object implements javax.jms.MessageListener
| Fields Summary |
|---|
| private javax.jms.TopicConnection | connect | | private javax.jms.TopicSession | session | | private javax.jms.TopicPublisher | publisher | | private javax.jms.Topic | hotDealsTopic | | private javax.jms.TopicSubscriber | subscriber | | private static boolean | inRollback | | private static boolean | rollbackOnly |
| Constructors Summary |
|---|
public Retailer(String broker, String username, String password)
try{
TopicConnectionFactory factory = null;
InitialContext jndi = null;
Properties env = new Properties();
// ... specify the JNDI properties specific to the JNDI SPI being used
env.put("BROKER",broker);
jndi = new InitialContext(env);
factory =
(TopicConnectionFactory)jndi.lookup("TopicConnectionFactory");
connect = factory.createTopicConnection (username, password);
connect.setClientID(username);
session =
connect.createTopicSession(true,Session.AUTO_ACKNOWLEDGE);
hotDealsTopic = (Topic)jndi.lookup("Hot Deals");
subscriber = session.createDurableSubscriber(hotDealsTopic,
"Hot Deals Subscription");
publisher = session.createPublisher(null);
subscriber.setMessageListener(this);
connect.start();
}catch (javax.jms.JMSException jmse){
jmse.printStackTrace();
System.exit(1);
}catch(javax.naming.NamingException jne){
jne.printStackTrace(); System.exit(1);
}
|
| Methods Summary |
|---|
| private void | autoBuy(javax.jms.Message message)
int count = 1000;
try{
boolean redelivered = message.getJMSRedelivered();
StreamMessage strmMsg = (StreamMessage)message;
if( redelivered ){
System.out.println("\nMessage redelivered, inRollback: "
+ inRollback + " rollbackOnly: " + rollbackOnly );
strmMsg.reset();
}
if( strmMsg.propertyExists("SEQUENCE_MARKER") ){
String sequence = strmMsg.getStringProperty( "SEQUENCE_MARKER" );
if( sequence.equalsIgnoreCase("END_SEQUENCE") )
{
if( redelivered && inRollback ){ // at the end, start fresh
inRollback = false;
rollbackOnly = false;
session.commit();
}
else if( rollbackOnly ){
inRollback = true;
session.rollback();
}
else
session.commit();
}
return;
}
if( rollbackOnly )
return; // ignore all other messages while in rollback mode
String dealDesc = strmMsg.readString();
String itemDesc = strmMsg.readString();
float oldPrice = strmMsg.readFloat();
float newPrice = strmMsg.readFloat();
System.out.println("Received Hot Buy :"+dealDesc);
// if price reduction greater than 10 percent, buy
if (newPrice == 0 || oldPrice / newPrice > 1.1){
System.out.println ("\nBuying " + count + " " + itemDesc);
TextMessage textMsg = session.createTextMessage();
textMsg.setText(count + " " + itemDesc );
javax.jms.Topic buyTopic =
(javax.jms.Topic)message.getJMSReplyTo();
//publisher = session.createPublisher(buytopic);
textMsg.setJMSCorrelationID("DurableRetailer");
publisher.publish(
buyTopic,
textMsg,
javax.jms.DeliveryMode.PERSISTENT,
javax.jms.Message.DEFAULT_PRIORITY,
1800000);
}else{
System.out.println ("\nBad Deal. Not buying");
//session.rollback();
rollbackOnly = true;
}
}catch (javax.jms.JMSException jmse){
jmse.printStackTrace();
}
| | private void | exit(java.lang.String s)
try {
if ( s != null &&
s.equalsIgnoreCase("unsubscribe"))
{
subscriber.close();
session.unsubscribe("Hot Deals Subscription");
}
connect.close();
}catch (javax.jms.JMSException jmse){
jmse.printStackTrace();
}
System.exit(0);
| | public static void | main(java.lang.String[] argv)
String broker, username, password;
if(argv.length == 3){
broker = argv[0];
username = argv[1];
password = argv[2];
}else{
System.out.println("Invalid arguments. Should be: ");
System.out.println
("java Retailer broker username password");
return;
}
Retailer retailer = new Retailer(broker, username, password);
try{
System.out.println("\nRetailer application started.\n");
// Read all standard input and send it as a message.
java.io.BufferedReader stdin =
new java.io.BufferedReader
( new java.io.InputStreamReader( System.in ) );
while ( true ){
String s = stdin.readLine();
if ( s == null || s.length() == 0 )retailer.exit(null);
else if ( s.equalsIgnoreCase("unsubscribe") )
retailer.exit ( s );
else if ( s.equalsIgnoreCase("commit") )
{
try{
System.out.println("\nGonna Commit");
retailer.session.commit();
}catch( javax.jms.JMSException jmse ){jmse.printStackTrace();}
}
else if ( s.equalsIgnoreCase("rollback") )
{
try{
System.out.println("\nRolling back");
retailer.session.rollback();
}catch( javax.jms.JMSException jmse ){jmse.printStackTrace();}
}
}
}catch ( java.io.IOException ioe ){
ioe.printStackTrace();
}
| | public void | onMessage(javax.jms.Message aMessage)
try{
autoBuy(aMessage);
}catch (java.lang.RuntimeException rte){
rte.printStackTrace();
}
|
|
