Wholesalerpublic class Wholesaler extends Object implements javax.jms.MessageListener, javax.jms.ExceptionListener
| Fields Summary |
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| private javax.jms.TopicConnection | connect | | private javax.jms.TopicSession | session | | private javax.jms.TopicPublisher | publisher | | private javax.jms.TopicSubscriber | subscriber | | private javax.jms.Topic | hotDealsTopic | | private javax.jms.Topic | buyOrdersTopic | | private String | mBroker | | private String | mUsername | | private String | mPassword | | private static final int | CONNECTION_RETRY_PERIOD | | private static boolean | inSequence |
| Constructors Summary |
|---|
public Wholesaler(String broker, String username, String password)
mBroker = broker;
mUsername = username;
mPassword = password;
establishConnection(broker, username, password);
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| Methods Summary |
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| private void | establishConnection(java.lang.String broker, java.lang.String username, java.lang.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");
while (connect == null)
{
try{
connect = factory.createTopicConnection (username, password);
} catch (javax.jms.JMSException jmse)
{
System.out.print("Cannot connect to message server: " + broker + "...");
System.out.println("Pausing " +
CONNECTION_RETRY_PERIOD / 1000 + " seconds before retry.");
try
{
Thread.sleep(CONNECTION_RETRY_PERIOD);
} catch (java.lang.InterruptedException ie) {ie.printStackTrace();}
continue;
}
}
System.out.println("\nConnection established");
session =
connect.createTopicSession(false,Session.AUTO_ACKNOWLEDGE);
hotDealsTopic = (Topic)jndi.lookup("Hot Deals");
buyOrdersTopic = (Topic)jndi.lookup("Buy Order");
publisher = session.createPublisher(hotDealsTopic);
//buyOrdersTopic = session.createTemporaryTopic();
subscriber = session.createSubscriber(buyOrdersTopic);
subscriber.setMessageListener(this);
connect.setExceptionListener( (javax.jms.ExceptionListener) this);
connect.start();
}catch (javax.jms.JMSException jmse){
jmse.printStackTrace(); System.exit(1);
}catch(javax.naming.NamingException jne){
jne.printStackTrace(); System.exit(1);
}
| | public void | exit()
try{
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 Wholesaler broker username password");
return;
}
Wholesaler wholesaler = new Wholesaler(broker, username, password);
try{
// Read all standard input and send it as a message.
java.io.BufferedReader stdin = new java.io.BufferedReader
(new java.io.InputStreamReader( System.in ) );
System.out.println ("Enter: Item, Old Price, New Price ");
System.out.println("\ne.g. Bowling Shoes, 100.00, 55.00");
while ( true ){
String dealDesc = stdin.readLine();
if( dealDesc != null && dealDesc.length() > 0 ){
if( dealDesc.substring(0,3).equalsIgnoreCase("END") ){
wholesaler.sendSequenceMarker( "END_SEQUENCE" );
}else{
// parse the deal description
StringTokenizer tokenizer =
new StringTokenizer(dealDesc,",") ;
String itemdesc = tokenizer.nextToken();
String temp = tokenizer.nextToken();
float oldprice =
Float.valueOf(temp.trim()).floatValue();
temp = tokenizer.nextToken();
float newprice =
Float.valueOf(temp.trim()).floatValue();
wholesaler.publishPriceQuotes(dealDesc,username,
itemdesc, oldprice,newprice);
}
}else{
wholesaler.exit();
}
}
}catch( java.io.IOException ioe ){
ioe.printStackTrace();
}
| | public void | onException(javax.jms.JMSException jsme)
// See if connection was dropped.
// Tell the user that there is a problem.
System.err.println ("\n\nThere is a problem with the connection.");
System.err.println (" JMSException: " + jsme.getMessage());
System.err.println ("Please wait while the application tries to "+
"re-establish the connection...");
// Reestablish the connection
connect = null;
establishConnection(mBroker, mUsername, mPassword);
| | public void | onMessage(javax.jms.Message message)
try{
TextMessage textMessage = (TextMessage) message;
String text = textMessage.getText();
System.out.println("Order received - "+text+
" from " + message.getJMSCorrelationID());
}catch (java.lang.Exception rte){
rte.printStackTrace();
}
| | private void | publishPriceQuotes(java.lang.String dealDesc, java.lang.String username, java.lang.String itemdesc, float oldprice, float newprice)
try{
javax.jms.StreamMessage message = session.createStreamMessage();
message.writeString(dealDesc);
message.writeString(itemdesc);
message.writeFloat(oldprice);
message.writeFloat(newprice);
message.setStringProperty("Username", username);
message.setStringProperty("Itemdesc", itemdesc);
message.setJMSReplyTo(buyOrdersTopic);
publisher.publish(
message,
javax.jms.DeliveryMode.PERSISTENT,
javax.jms.Message.DEFAULT_PRIORITY,
1800000);
}catch ( javax.jms.JMSException jmse ){
jmse.printStackTrace();
}
| | private void | sendSequenceMarker(java.lang.String sequenceMarker)
try{
javax.jms.StreamMessage message = session.createStreamMessage();
message.setStringProperty("SEQUENCE_MARKER",sequenceMarker);
publisher.publish(
message,
javax.jms.DeliveryMode.PERSISTENT,
javax.jms.Message.DEFAULT_PRIORITY,
1800000);
}catch ( javax.jms.JMSException jmse ){
jmse.printStackTrace();
}
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