122 WCTME: Application Development and Case Study
private String targetQName = "SYSTEM.DEFAULT.LOCAL.QUEUE";
private String targetSFQ = "SFQ";
private boolean createdQM;
private boolean timeToQuit = false;
/**
* The public constructor
* It stores the bundle context,sets up an MQe client to send messages to
the server,
* and then sets up an MQe server to receive responses from the server
* @param context
*/
public ITSORentalsMQeImpl(BundleContext context) {
super();
this.context = context;
}
/**
* @see
com.itso.rentals.mqe.ITSORentalsMQeService#init(java.util.Properties)
*/
public boolean init(Properties p) {
//deal with properties
if (p != null) {
String standAloneString =
p.getProperty("itso.mqe.standalone", "true");
standAlone = standAloneString.equalsIgnoreCase("true");
targetQMIPAddress =
p.getProperty("itso.mqe.QMIPAddress", "127.0.0.1");
targetQMPort = p.getProperty("itso.mqe.QMPort", "8086");
targetQMName = p.getProperty("itso.mqe.QMName", "Transponder");
myQMName = p.getProperty("itso.mqe.DeviceQMName", "ITSOQueues");
myRegistry = myQMName;
}
if (!standAlone) {
mqeAdmin = new MQeAdmin(myQMName, myRegistry);
setupMQeClient();
setupMQeServer();
}
//Resolve Database service
ServiceReference dbRef =
context.getServiceReference(
ITSORentalsDatabaseService.class.getName());
if (dbRef != null) {
databaseService =
(ITSORentalsDatabaseService) context.getService(dbRef);
Chapter 5. Messaging 123
System.out.println("Found DataBase service!");
}
return true;
}
/**
* sends a message when a customer arrives
* @param String - contract number of the customer who has arrived
* @return boolean - always returns true
*/
public boolean customerArrived(String contractNumber) {
if (standAlone) {
databaseService.updateVechicleLocation(contractNumber, "A" +
count++);
} else {
sendMessage(contractNumber);
}
return true;
}
/**
* Checks to see if a QM is already running. If not it uses the MQeAdmin
* to define a new QM, start it then create a connection definition
* to the receivers QM. It then adds a remote queue definition to the
* receivers local queue.
*/
public void setupMQeClient() {
if (MQeQueueManager.getDefaultQueueManager() == null) {
mqeAdmin.defineQM();
mqeAdmin.startQM();
mqeAdmin.setRemoteQueueManagerName(targetQMName);
mqeAdmin.createConnection(targetQMIPAddress, targetQMPort);
mqeAdmin.addRemoteQueueDefinition(targetQMName, targetQName);
} else {
mqeAdmin.startQM();
}
}
/**
* Sets up the MQe Server. Calls MQeAdmin to create and start a
listener, then
124 WCTME: Application Development and Case Study
* adds a message itself as a message listener
*/
public void setupMQeServer() {
mqeAdmin.createHomeServerQueue(targetQMName, targetSFQ);
Thread kicker = new Thread(this);
kicker.start();
MQeQueueManager qm = MQeQueueManager.getDefaultQueueManager();
try {
qm.addMessageListener(this, MQe.System_Default_Queue_Name, null);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* This method is called by the queue manager when a message arrives
* The method extracts the contract id and slot number from the message,
and updates
* the database with the information
*/
public void messageArrived(MQeMessageEvent arg0) throws Exception {
MQeQueueManager qm = MQeQueueManager.getDefaultQueueManager();
//until we run out of messages
for (;;) {
try {
MQeMsgObject msg = qm.getMessage(null,
MQe.System_Default_Queue_Name, null, null, 0);
String contractID = msg.getAscii("ContractID");
String slot = msg.getAscii("Slot");
System.out.println( "In messageArrived. Updating " + contractID +
" to slot " + slot);
databaseService.updateVechicleLocation(contractID, slot);
} catch (MQeMessageStoreException mqemse) {
System.out.println("Exception in messageArrived. [" +
mqemse.getMessage() + "]");
mqemse.printStackTrace();
} catch (Exception e) {
if (!e.getMessage().equalsIgnoreCase("Message not found")) {
System.out.println("Exception in messageArrived. [" +
e.getMessage() + "]");
e.printStackTrace();
}
break;
}
Chapter 5. Messaging 125
}
}
/**
* Creates a message to send to the server. It includes the
* "return address" information, including our queue manager
* and queue names, plus the text of the message
*
* @param text - the text to be sent in the message
* @return true if the message is sent without an exception
*/
public boolean sendMessage(String text) {
if (mqeAdmin != null) {
try {
String qmName =
MQeQueueManager.getDefaultQueueManager().getName();
String qName = MQe.System_Default_Queue_Name;
MQeQueueManager qm = null;
MQeMsgObject outMessage = new MQeMsgObject();
outMessage.putAscii("ContractID", text);
outMessage.putAscii(MQe.Msg_ReplyToQ, qName);
outMessage.putAscii(MQe.Msg_ReplyToQMgr, qmName);
qm = MQeQueueManager.getDefaultQueueManager();
qm.putMessage(
targetQMName,
MQe.System_Default_Queue_Name,
outMessage,
null,
0);
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
} else {
return false;
}
}
public void shutdown() {
if (!standAlone) {
timeToQuit = true;
mqeAdmin.stopQM();
}
126 WCTME: Application Development and Case Study
}
/**
* The run method sleeps for 15 seconds and then tells the queue
* manager to check for messages
*/
public void run() {
while (!timeToQuit) {
try {
MQeQueueManager.getDefaultQueueManager().triggerTransmission();
Thread.sleep(15000);
} catch (Exception e) {
e.printStackTrace();
}
}
}
20.Organize Imports and Save the file.
21.Open the ExtensionServicesBundleActivator.java file (in the default package)
and add the following code to the class:
private ServiceRegistration svcdb;
private BundleContext context;
private ITSORentalsMQeImpl mqeSvc;
22.Add the following code in Example 5-2 at the end of the start() method:
Example 5-2 Appending the start() method
this.context = context;
mqeSvc = new ITSORentalsMQeImpl(context);
svcdb = context.registerService(
ITSORentalsMQeService.class.getName(),
mqeSvc,
null);
This code registers the messaging service, so that other bundles can resolve
it.
23.Add the following code at the end of the stop() method:
mqeSvc.shutdown();
svcdb.unregister();
Note: There will be some unresolved external references until we build the
MQAdmin class.
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