A Message Acknowledgment Example

The AckEquivExample.java client shows how both of the following two scenarios ensure that a message will not be acknowledged until processing of it is complete:

• Using an asynchronous message consumer (a message listener) in an AUTO_ACKNOWLEDGE session

• Using a synchronous receiver in a CLIENT_ACKNOWLEDGE session

With a message listener, the automatic acknowledgment happens when the onMessage method returns (that is, after message processing has finished). With a synchronous receiver, the client acknowledges the message after processing is complete. If you use AUTO_ACKNOWLEDGE with a synchronous receive, the acknowledgment happens immediately after the receive call; if any subsequent processing steps fail, the message cannot be redelivered.

The example is in the following directory:

tut-install/examples/jms/advanced/ackequivexample/src/java/

The example contains an AsynchSubscriber class with a TextListener class, a MultiplePublisher class, a SynchReceiver class, a SynchSender class, a main method, and a method that runs the other classes’ threads.

The example uses the following objects:

• jms/ConnectionFactory, jms/Queue, and jms/Topic: resources that you created in To Create JMS Administered Objects for the Synchronous Receive Example

• jms/ControlQueue: an additional queue

• jms/DurableConnectionFactory: a connection factory with a client ID (see Creating Durable Subscriptions, for more information)

To create the new queue and connection factory, you can use Ant targets defined in the file tut-install/examples/jms/advanced/ackequivexample/build.xml.

To Build, Package, Deploy, and Run the ackequivexample Using NetBeans IDE

1. In a terminal window, go to the following directory:

   tut-install/examples/jms/advanced/ackequivexample/
   

2. To create the objects needed in this example, type the following commands:

   ant create-control-queue ant create-durable-cf

3. To build and package the client, follow these steps.

   1. In NetBeans IDE, select File->Open Project.

   2. In the Open Project dialog, navigate to:

      tut-install/examples/jms/advanced/

   3. Select the ackequivexample folder.

   4. Select the Open as Main Project check box.

   5. Click Open Project.

   6. In the Projects tab, right-click the project and select Build.

4. To run the client, right-click the ackequivexample project and select Run.

   The client output looks something like this (along with some application client container output):

   Queue name is jms/ControlQueue Queue name is jms/Queue Topic name is jms/Topic Connection factory name is jms/DurableConnectionFactory SENDER: Created client-acknowledge session SENDER: Sending message: Here is a client-acknowledge message RECEIVER: Created client-acknowledge session RECEIVER: Processing message: Here is a client-acknowledge message RECEIVER: Now I’ll acknowledge the message SUBSCRIBER: Created auto-acknowledge session SUBSCRIBER: Sending synchronize message to control queue PUBLISHER: Created auto-acknowledge session PUBLISHER: Receiving synchronize messages from control queue; count = 1 PUBLISHER: Received synchronize message; expect 0 more PUBLISHER: Publishing message: Here is an auto-acknowledge message 1 PUBLISHER: Publishing message: Here is an auto-acknowledge message 2 SUBSCRIBER: Processing message: Here is an auto-acknowledge message 1 PUBLISHER: Publishing message: Here is an auto-acknowledge message 3 SUBSCRIBER: Processing message: Here is an auto-acknowledge message 2 SUBSCRIBER: Processing message: Here is an auto-acknowledge message 3

5. After you run the client, you can delete the destination resource jms/ControlQueue. Go to the directory tut-install/examples/jms/advanced/ackequivexample/ and type the following command:

   ant delete-control-queue

   You will need the other resources for other examples.

To Build, Package, Deploy, and Run ackequivexample Using Ant

1. In a terminal window, go to the following directory:

   tut-install/examples/jms/advanced/ackequivexample/
   

2. To create the objects needed in this example, type the following commands:

   ant create-control-queue ant create-durable-cf

3. To compile and package the client, type the following command:

   ant

4. To deploy the client JAR file to the GlassFish Server, then retrieve the client stubs, type the following command:

   ant getclient

   Ignore the message that states that the application is deployed at a URL.

5. Because this example takes no command-line arguments, you can run the client using the following command:

   ant run

   Alternatively, you can type the following command:

   appclient -client client-jar/ackequivexampleClient.jar

   The client output looks something like this (along with some application client container output):

   Queue name is jms/ControlQueue Queue name is jms/Queue Topic name is jms/Topic Connection factory name is jms/DurableConnectionFactory SENDER: Created client-acknowledge session SENDER: Sending message: Here is a client-acknowledge message RECEIVER: Created client-acknowledge session RECEIVER: Processing message: Here is a client-acknowledge message RECEIVER: Now I’ll acknowledge the message SUBSCRIBER: Created auto-acknowledge session SUBSCRIBER: Sending synchronize message to control queue PUBLISHER: Created auto-acknowledge session PUBLISHER: Receiving synchronize messages from control queue; count = 1 PUBLISHER: Received synchronize message; expect 0 more PUBLISHER: Publishing message: Here is an auto-acknowledge message 1 PUBLISHER: Publishing message: Here is an auto-acknowledge message 2 SUBSCRIBER: Processing message: Here is an auto-acknowledge message 1 PUBLISHER: Publishing message: Here is an auto-acknowledge message 3 SUBSCRIBER: Processing message: Here is an auto-acknowledge message 2 SUBSCRIBER: Processing message: Here is an auto-acknowledge message 3

6. After you run the client, you can delete the destination resource jms/ControlQueue. Go to the directory tut-install/examples/jms/advanced/ackequivexample/ and type the following command:

   ant delete-control-queue

   You will need the other resources for other examples.