Mega Code Archive
Demonstrates the use of transactions in a JMS application
<![CDATA[
/*
* @(#)TransactedExample.java 1.4 04/09/15
*
* Copyright (c) 2000-2002 Sun Microsystems, Inc. All Rights Reserved.
*
* Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
* modify and redistribute this software in source and binary code form,
* provided that i) this copyright notice and license appear on all copies of
* the software; and ii) Licensee does not utilize the software in a manner
* which is disparaging to Sun.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
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*
* This software is not designed or intended for use in on-line control of
* aircraft, air traffic, aircraft navigation or aircraft communications; or in
* the design, construction, operation or maintenance of any nuclear
* facility. Licensee represents and warrants that it will not use or
* redistribute the Software for such purposes.
*/
import java.util.Random;
import java.util.Hashtable;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.ConnectionFactory;
import javax.jms.Connection;
import javax.jms.MessageProducer;
import javax.jms.MessageConsumer;
import javax.jms.Message;
import javax.jms.MapMessage;
import javax.jms.MessageListener;
import javax.jms.JMSException;
/**
* The TransactedExample class demonstrates the use of transactions in a JMS
* application. It represents a highly simplified eCommerce application, in
* which the following things happen:
*
* <pre>
* Legend
* R - Retailer
* V - Vendor
* S - Supplier
* O - Order Queue
* C - Confirmation Queue
* ()- Thread
* []- Queue
*
* 2(b) 3
* 1 2(a) /+------->[S1 O]<-----------(S1)
* /+-->[V O]<----+ / |
* / \ / 3 |
* / \ / 5 v------------------+
* (R) ( V )-------->[V C] 4
* \ / \ ^------------------+
* \ / \ |
* \ 7 6 / \ |
* +---->[R C]<--+ \ 2(c) 4 |
* +------->[SN O]<-----------(SN)
* </pre>
*
* <ol>
* <li>A retailer sends a message to the vendor order queue ordering a quantity
* of computers. It waits for the vendor's reply.
* <li>The vendor receives the retailer's order message and places an order
* message into each of its suppliers' order queues, all in one transaction.
* This JMS transaction combines one synchronous receive with multiple sends.
* <li>One supplier receives the order from its order queue, checks its
* inventory, and sends the items ordered to the order message's replyTo
* field. If it does not have enough in stock, it sends what it has.
* The synchronous receive and the send take place in one JMS transaction.
* <li>The other supplier receives the order from its order queue, checks its
* inventory, and sends the items ordered to the order message's replyTo
* field. If it does not have enough in stock, it sends what it has.
* The synchronous receive and the send take place in one JMS transaction.
* <li>The vendor receives the replies from the suppliers from its confirmation
* queue and updates the state of the order. Messages are processed by an
* asynchronous message listener; this step illustrates using JMS transactions
* with a message listener.
* <li>When all outstanding replies are processed for a given order, the vendor
* sends a message notifying the retailer whether or not it can fulfill the
* order.
* <li>The retailer receives the message from the vendor.
* </ol>
* <p>
* The program contains five classes: Retailer, Vendor, GenericSupplier,
* VendorMessageListener, and Order. It also contains a main method and a
* method that runs the threads of the Retail, Vendor, and two supplier classes.
* <p>
* All the messages use the MapMessage message type. Synchronous receives are
* used for all message reception except for the case of the vendor processing
* the replies of the suppliers. These replies are processed asynchronously
* and demonstrate how to use transactions within a message listener.
* <p>
* All classes except Retailer use transacted sessions.
* <p>
* The program uses five queues. Before you run the program, create the
* queues and name them A, B, C, D and E.
* <p>
* When you run the program, specify on the command line the number of
* computers to be ordered.
*
* @author Kim Haase
* @author Joseph Fialli
* @version 1.3, 08/18/00
*/
public class TransactedExample {
public static String vendorOrderQueueName = null;
public static String retailerConfirmationQueueName = null;
public static String monitorOrderQueueName = null;
public static String storageOrderQueueName = null;
public static String vendorConfirmationQueueName = null;
public static int exitResult = 0;
/**
* The Retailer class orders a number of computers by sending a message
* to a vendor. It then waits for the order to be confirmed.
* <p>
* In this example, the Retailer places two orders, one for the quantity
* specified on the command line and one for twice that number.
* <p>
* This class does not use transactions.
*
* @author Kim Haase
* @author Joseph Fialli
* @version 1.3, 08/18/00
*/
public static class Retailer extends Thread {
int quantity = 0;
/**
* Constructor. Instantiates the retailer with the quantity of
* computers being ordered.
*
* @param q the quantity specified in the program arguments
*/
public Retailer(int q) {
quantity = q;
}
/**
* Runs the thread.
*/
public void run() {
ConnectionFactory connectionFactory = null;
Connection connection = null;
Session session = null;
Queue vendorOrderQueue = null;
Queue retailerConfirmationQueue = null;
MessageProducer msgProducer = null;
MapMessage outMessage = null;
MessageConsumer orderConfirmationConsumer = null;
MapMessage inMessage = null;
try {
connectionFactory =
SampleUtilities.getConnectionFactory();
connection =
connectionFactory.createConnection();
session = connection.createSession(false,
Session.AUTO_ACKNOWLEDGE);
vendorOrderQueue =
SampleUtilities.getQueue(vendorOrderQueueName, session);
retailerConfirmationQueue =
SampleUtilities.getQueue(retailerConfirmationQueueName,
session);
} catch (Exception e) {
System.out.println("Connection problem: " + e.toString());
System.out.println("Program assumes five queues named A B C D E");
if (connection != null) {
try {
connection.close();
} catch (JMSException ee) {}
}
System.exit(1);
}
/*
* Create non-transacted session and sender for vendor order
* queue.
* Create message to vendor, setting item and quantity values.
* Send message.
* Create receiver for retailer confirmation queue.
* Get message and report result.
* Send an end-of-message-stream message so vendor will
* stop processing orders.
*/
try {
msgProducer = session.createProducer(vendorOrderQueue);
outMessage = session.createMapMessage();
outMessage.setString("Item", "Computer(s)");
outMessage.setInt("Quantity", quantity);
outMessage.setJMSReplyTo(retailerConfirmationQueue);
msgProducer.send(outMessage);
System.out.println("Retailer: ordered " + quantity
+ " computer(s)");
orderConfirmationConsumer =
session.createConsumer(retailerConfirmationQueue);
connection.start();
inMessage = (MapMessage) orderConfirmationConsumer.receive();
if (inMessage.getBoolean("OrderAccepted") == true) {
System.out.println("Retailer: Order filled");
} else {
System.out.println("Retailer: Order not filled");
}
System.out.println("Retailer: placing another order");
outMessage.setInt("Quantity", quantity * 2);
msgProducer.send(outMessage);
System.out.println("Retailer: ordered "
+ outMessage.getInt("Quantity")
+ " computer(s)");
inMessage =
(MapMessage) orderConfirmationConsumer.receive();
if (inMessage.getBoolean("OrderAccepted") == true) {
System.out.println("Retailer: Order filled");
} else {
System.out.println("Retailer: Order not filled");
}
// Send a non-text control message indicating end of messages.
msgProducer.send(session.createMessage());
} catch (Exception e) {
System.out.println("Retailer: Exception occurred: "
+ e.toString());
e.printStackTrace();
exitResult = 1;
} finally {
if (connection != null) {
try {
connection.close();
} catch (JMSException e) {
exitResult = 1;
}
}
}
}
}
/**
* The Vendor class uses one transaction to receive the computer order from
* the retailer and order the needed number of monitors and disk drives
* from its suppliers. At random intervals, it throws an exception to
* simulate a database problem and cause a rollback.
* <p>
* The class uses an asynchronous message listener to process replies from
* suppliers. When all outstanding supplier inquiries complete, it sends a
* message to the Retailer accepting or refusing the order.
*
* @author Kim Haase
* @author Joseph Fialli
* @version 1.3, 08/18/00
*/
public static class Vendor extends Thread {
Random rgen = new Random();
int throwException = 1;
/**
* Runs the thread.
*/
public void run() {
ConnectionFactory connectionFactory = null;
Connection connection = null;
Session session = null;
Session asyncSession = null;
Queue vendorOrderQueue = null;
Queue monitorOrderQueue = null;
Queue storageOrderQueue = null;
Queue vendorConfirmationQueue = null;
MessageConsumer vendorOrderMessageConsumer = null;
MessageProducer monitorOrderMessageProducer = null;
MessageProducer storageOrderMessageProducer = null;
MapMessage orderMessage = null;
MessageConsumer vendorConfirmationMessageConsumer = null;
VendorMessageListener listener = null;
Message inMessage = null;
MapMessage vendorOrderMessage = null;
Message endOfMessageStream = null;
Order order = null;
int quantity = 0;
try {
connectionFactory =
SampleUtilities.getConnectionFactory();
connection =
connectionFactory.createConnection();
session = connection.createSession(true, 0);
asyncSession = connection.createSession(true, 0);
vendorOrderQueue =
SampleUtilities.getQueue(vendorOrderQueueName, session);
monitorOrderQueue =
SampleUtilities.getQueue(monitorOrderQueueName, session);
storageOrderQueue =
SampleUtilities.getQueue(storageOrderQueueName, session);
vendorConfirmationQueue =
SampleUtilities.getQueue(vendorConfirmationQueueName, session);
} catch (Exception e) {
System.out.println("Connection problem: " + e.toString());
System.out.println("Program assumes six queues named A B C D E F");
if (connection != null) {
try {
connection.close();
} catch (JMSException ee) {}
}
System.exit(1);
}
try {
/*
* Create receiver for vendor order queue, sender for
* supplier order queues, and message to send to suppliers.
*/
vendorOrderMessageConsumer =
session.createConsumer(vendorOrderQueue);
monitorOrderMessageProducer =
session.createProducer(monitorOrderQueue);
storageOrderMessageProducer =
session.createProducer(storageOrderQueue);
orderMessage = session.createMapMessage();
/*
* Configure an asynchronous message listener to process
* supplier replies to inquiries for parts to fill order.
* Start delivery.
*/
vendorConfirmationMessageConsumer =
asyncSession.createConsumer(vendorConfirmationQueue);
listener = new VendorMessageListener(asyncSession, 2);
vendorConfirmationMessageConsumer.setMessageListener(listener);
connection.start();
/*
* Process orders in vendor order queue.
* Use one transaction to receive order from order queue
* and send messages to suppliers' order queues to order
* components to fulfill the order placed with the vendor.
*/
while (true) {
try {
// Receive an order from a retailer.
inMessage = vendorOrderMessageConsumer.receive();
if (inMessage instanceof MapMessage) {
vendorOrderMessage = (MapMessage) inMessage;
} else {
/*
* Message is an end-of-message-stream message from
* retailer. Send similar messages to suppliers,
* then break out of processing loop.
*/
endOfMessageStream = session.createMessage();
endOfMessageStream.setJMSReplyTo(vendorConfirmationQueue);
monitorOrderMessageProducer.send(endOfMessageStream);
storageOrderMessageProducer.send(endOfMessageStream);
session.commit();
break;
}
/*
* A real application would check an inventory database
* and order only the quantities needed. Throw an
* exception every few times to simulate a database
* concurrent-access exception and cause a rollback.
*/
if (rgen.nextInt(3) == throwException) {
throw new JMSException("Simulated database concurrent access exception");
}
// Record retailer order as a pending order.
order = new Order(vendorOrderMessage);
/*
* Set order number and reply queue for outgoing
* message.
*/
orderMessage.setInt("VendorOrderNumber",
order.orderNumber);
orderMessage.setJMSReplyTo(vendorConfirmationQueue);
quantity = vendorOrderMessage.getInt("Quantity");
System.out.println("Vendor: Retailer ordered " +
quantity + " " +
vendorOrderMessage.getString("Item"));
// Send message to monitor supplier.
orderMessage.setString("Item", "Monitor");
orderMessage.setInt("Quantity", quantity);
monitorOrderMessageProducer.send(orderMessage);
System.out.println("Vendor: ordered " + quantity + " "
+ orderMessage.getString("Item")
+ "(s)");
/*
* Reuse message to send to storage supplier, changing
* only item name.
*/
orderMessage.setString("Item", "Hard Drive");
storageOrderMessageProducer.send(orderMessage);
System.out.println("Vendor: ordered " + quantity + " "
+ orderMessage.getString("Item")
+ "(s)");
// Commit session.
session.commit();
System.out.println(" Vendor: committed transaction 1");
} catch(JMSException e) {
System.out.println("Vendor: JMSException occurred: "
+ e.toString());
e.printStackTrace();
session.rollback();
System.out.println(" Vendor: rolled back transaction 1");
exitResult = 1;
}
}
// Wait till suppliers get back with answers.
listener.monitor.waitTillDone();
} catch (JMSException e) {
System.out.println("Vendor: Exception occurred: " +
e.toString());
e.printStackTrace();
exitResult = 1;
} finally {
if (connection != null) {
try {
connection.close();
} catch (JMSException e) {
exitResult = 1;
}
}
}
}
}
/**
* The Order class represents a Retailer order placed with a Vendor.
* It maintains a table of pending orders.
*
* @author Joseph Fialli
* @version 1.3, 08/18/00
*/
public static class Order {
private static Hashtable pendingOrders = new Hashtable();
private static int nextOrderNumber = 1;
private static final int PENDING_STATUS = 1;
private static final int CANCELLED_STATUS = 2;
private static final int FULFILLED_STATUS = 3;
int status;
public final int orderNumber;
public int quantity;
public final MapMessage order; // original order from retailer
public MapMessage monitor = null; // reply from supplier
public MapMessage storage = null; // reply from supplier
/**
* Returns the next order number and increments the static variable
* that holds this value.
*
* @return the next order number
*/
private static int getNextOrderNumber() {
int result = nextOrderNumber;
nextOrderNumber++;
return result;
}
/**
* Constructor. Sets order number; sets order and quantity from
* incoming message. Sets status to pending, and adds order to hash
* table of pending orders.
*
* @param order the message containing the order
*/
public Order(MapMessage order) {
this.orderNumber = getNextOrderNumber();
this.order = order;
try {
this.quantity = order.getInt("Quantity");
} catch (JMSException je) {
System.err.println("Unexpected error. Message missing Quantity");
this.quantity = 0;
}
status = PENDING_STATUS;
pendingOrders.put(new Integer(orderNumber), this);
}
/**
* Returns the number of orders in the hash table.
*
* @return the number of pending orders
*/
public static int outstandingOrders() {
return pendingOrders.size();
}
/**
* Returns the order corresponding to a given order number.
*
* @param orderNumber the number of the requested order
* @return the requested order
*/
public static Order getOrder(int orderNumber) {
return (Order) pendingOrders.get(new Integer(orderNumber));
}
/**
* Called by the onMessage method of the VendorMessageListener class
* to process a reply from a supplier to the Vendor.
*
* @param component the message from the supplier
* @return the order with updated status information
*/
public Order processSubOrder(MapMessage component) {
String itemName = null;
// Determine which subcomponent this is.
try {
itemName = component.getString("Item");
} catch (JMSException je) {
System.err.println("Unexpected exception. Message missing Item");
}
if (itemName.compareTo("Monitor") == 0) {
monitor = component;
} else if (itemName.compareTo("Hard Drive") == 0 ) {
storage = component;
}
/*
* If notification for all subcomponents has been received,
* verify the quantities to compute if able to fulfill order.
*/
if ( (monitor != null) && (storage != null) ) {
try {
if (quantity > monitor.getInt("Quantity")) {
status = CANCELLED_STATUS;
} else if (quantity > storage.getInt("Quantity")) {
status = CANCELLED_STATUS;
} else {
status = FULFILLED_STATUS;
}
} catch (JMSException je) {
System.err.println("Unexpected exception " + je);
status = CANCELLED_STATUS;
}
/*
* Processing of order is complete, so remove it from
* pending-order list.
*/
pendingOrders.remove(new Integer(orderNumber));
}
return this;
}
/**
* Determines if order status is pending.
*
* @return true if order is pending, false if not
*/
public boolean isPending() {
return status == PENDING_STATUS;
}
/**
* Determines if order status is cancelled.
*
* @return true if order is cancelled, false if not
*/
public boolean isCancelled() {
return status == CANCELLED_STATUS;
}
/**
* Determines if order status is fulfilled.
*
* @return true if order is fulfilled, false if not
*/
public boolean isFulfilled() {
return status == FULFILLED_STATUS;
}
}
/**
* The VendorMessageListener class processes an order confirmation message
* from a supplier to the vendor.
* <p>
* It demonstrates the use of transactions within message listeners.
*
* @author Joseph Fialli
* @version 1.3, 08/18/00
*/
public static class VendorMessageListener implements MessageListener {
final SampleUtilities.DoneLatch monitor =
new SampleUtilities.DoneLatch();
private final Session session;
int numSuppliers;
/**
* Constructor. Instantiates the message listener with the session
* of the consuming class (the vendor).
*
* @param session the session of the consumer
* @param numSuppliers the number of suppliers
*/
public VendorMessageListener(Session session, int numSuppliers) {
this.session = session;
this.numSuppliers = numSuppliers;
}
/**
* Casts the message to a MapMessage and processes the order.
* A message that is not a MapMessage is interpreted as the end of the
* message stream, and the message listener sets its monitor state to
* all done processing messages.
* <p>
* Each message received represents a fulfillment message from
* a supplier.
*
* @param message the incoming message
*/
public void onMessage(Message message) {
/*
* If message is an end-of-message-stream message and this is the
* last such message, set monitor status to all done processing
* messages and commit transaction.
*/
if (! (message instanceof MapMessage)) {
if (Order.outstandingOrders() == 0) {
numSuppliers--;
if (numSuppliers == 0) {
monitor.allDone();
}
}
try {
session.commit();
} catch (JMSException je) {}
return;
}
/*
* Message is an order confirmation message from a supplier.
*/
int orderNumber = -1;
try {
MapMessage component = (MapMessage) message;
/*
* Process the order confirmation message and commit the
* transaction.
*/
orderNumber = component.getInt("VendorOrderNumber");
Order order =
Order.getOrder(orderNumber).processSubOrder(component);
session.commit();
/*
* If this message is the last supplier message, send message
* to Retailer and commit transaction.
*/
if (! order.isPending()) {
System.out.println("Vendor: Completed processing for order "
+ order.orderNumber);
Queue replyQueue = (Queue) order.order.getJMSReplyTo();
MessageProducer mp = session.createProducer(replyQueue);
MapMessage retailerConfirmationMessage =
session.createMapMessage();
if (order.isFulfilled()) {
retailerConfirmationMessage.setBoolean("OrderAccepted",
true);
System.out.println("Vendor: sent " + order.quantity
+ " computer(s)");
} else if (order.isCancelled()) {
retailerConfirmationMessage.setBoolean("OrderAccepted",
false);
System.out.println("Vendor: unable to send " +
order.quantity + " computer(s)");
}
mp.send(retailerConfirmationMessage);
session.commit();
System.out.println(" Vendor: committed transaction 2");
}
} catch (JMSException je) {
je.printStackTrace();
try {
session.rollback();
} catch (JMSException je2) {}
} catch (Exception e) {
e.printStackTrace();
try {
session.rollback();
} catch (JMSException je2) {}
}
}
}
/**
* The GenericSupplier class receives an item order from the
* vendor and sends a message accepting or refusing it.
*
* @author Kim Haase
* @author Joseph Fialli
* @version 1.3, 08/18/00
*/
public static class GenericSupplier extends Thread {
final String PRODUCT_NAME;
final String IN_ORDER_QUEUE;
int quantity = 0;
/**
* Constructor. Instantiates the supplier as the supplier for the
* kind of item being ordered.
*
* @param itemName the name of the item being ordered
* @param inQueue the queue from which the order is obtained
*/
public GenericSupplier(String itemName, String inQueue) {
PRODUCT_NAME = itemName;
IN_ORDER_QUEUE = inQueue;
}
/**
* Checks to see if there are enough items in inventory.
* Rather than go to a database, it generates a random number related
* to the order quantity, so that some of the time there won't be
* enough in stock.
*
* @return the number of items in inventory
*/
public int checkInventory() {
Random rgen = new Random();
return (rgen.nextInt(quantity * 5));
}
/**
* Runs the thread.
*/
public void run() {
ConnectionFactory connectionFactory = null;
Connection connection = null;
Session session = null;
Queue orderQueue = null;
MessageConsumer msgConsumer = null;
Message inMessage = null;
MapMessage orderMessage = null;
MapMessage outMessage = null;
try {
connectionFactory =
SampleUtilities.getConnectionFactory();
connection =
connectionFactory.createConnection();
session = connection.createSession(true, 0);
orderQueue =
SampleUtilities.getQueue(IN_ORDER_QUEUE, session);
} catch (Exception e) {
System.out.println("Connection problem: " + e.toString());
System.out.println("Program assumes six queues named A B C D E F");
if (connection != null) {
try {
connection.close();
} catch (JMSException ee) {}
}
System.exit(1);
}
// Create receiver for order queue and start message delivery.
try {
msgConsumer = session.createConsumer(orderQueue);
connection.start();
} catch (JMSException je) {
exitResult = 1;
}
/*
* Keep checking supplier order queue for order request until
* end-of-message-stream message is received.
* Receive order and send an order confirmation as one transaction.
*/
while (true) {
try {
inMessage = msgConsumer.receive();
if (inMessage instanceof MapMessage) {
orderMessage = (MapMessage) inMessage;
} else {
/*
* Message is an end-of-message-stream message.
* Send a similar message to reply queue, commit
* transaction, then stop processing orders by breaking
* out of loop.
*/
MessageProducer msgProducer =
session.createProducer((Queue) inMessage.getJMSReplyTo());
msgProducer.send(session.createMessage());
session.commit();
break;
}
// Extract quantity ordered from order message.
quantity = orderMessage.getInt("Quantity");
System.out.println(PRODUCT_NAME
+ " Supplier: Vendor ordered " + quantity + " "
+ orderMessage.getString("Item") + "(s)");
/*
* Create sender and message for reply queue.
* Set order number and item; check inventory and set
* quantity available.
* Send message to vendor and commit transaction.
*/
MessageProducer msgProducer =
session.createProducer((Queue) orderMessage.getJMSReplyTo());
outMessage = session.createMapMessage();
outMessage.setInt("VendorOrderNumber",
orderMessage.getInt("VendorOrderNumber"));
outMessage.setString("Item", PRODUCT_NAME);
int numAvailable = checkInventory();
if (numAvailable >= quantity) {
outMessage.setInt("Quantity", quantity);
} else {
outMessage.setInt("Quantity", numAvailable);
}
msgProducer.send(outMessage);
System.out.println(PRODUCT_NAME + " Supplier: sent "
+ outMessage.getInt("Quantity") + " "
+ outMessage.getString("Item") + "(s)");
session.commit();
System.out.println(" " + PRODUCT_NAME
+ " Supplier: committed transaction");
} catch (Exception e) {
System.out.println(PRODUCT_NAME
+ " Supplier: Exception occurred: " + e.toString());
e.printStackTrace();
exitResult = 1;
}
}
if (connection != null) {
try {
connection.close();
} catch (JMSException e) {
exitResult = 1;
}
}
}
}
/**
* Creates the Retailer and Vendor classes and the two supplier classes,
* then starts the threads.
*
* @param quantity the quantity specified on the command line
*/
public static void run_threads(int quantity) {
Retailer r = new Retailer(quantity);
Vendor v = new Vendor();
GenericSupplier ms = new GenericSupplier("Monitor",
monitorOrderQueueName);
GenericSupplier ss = new GenericSupplier("Hard Drive",
storageOrderQueueName);
r.start();
v.start();
ms.start();
ss.start();
try {
r.join();
v.join();
ms.join();
ss.join();
} catch (InterruptedException e) {}
}
/**
* Reads the order quantity from the command line, then
* calls the run_threads method to execute the program threads.
*
* @param args the quantity of computers being ordered
*/
public static void main(String[] args) {
TransactedExample te = new TransactedExample();
int quantity = 0;
if (args.length != 1) {
System.out.println("Usage: java TransactedExample <integer>");
System.out.println("Program assumes five queues named A B C D E");
System.exit(1);
}
te.vendorOrderQueueName = new String("A");
te.retailerConfirmationQueueName = new String("B");
te.monitorOrderQueueName = new String("C");
te.storageOrderQueueName = new String("D");
te.vendorConfirmationQueueName = new String("E");
quantity = (new Integer(args[0])).intValue();
System.out.println("Quantity to be ordered is " + quantity);
if (quantity > 0) {
te.run_threads(quantity);
} else {
System.out.println("Quantity must be positive and nonzero");
te.exitResult = 1;
}
SampleUtilities.exit(te.exitResult);
}
}
jms.zip( 65 k)
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