ejb-timer: Example of EJB Timer Service - @Schedule and @Timeout

Author: Ondrej Zizka [email protected]
Level: Beginner
Technologies: EJB Timer
Summary: The ejb-timer quickstart demonstrates how to use the EJB timer service @Schedule and @Timeout annotations with ${product.name}.
Target Product: ${product.name}
Source: <${github.repo.url}>

What is it?

The ejb-timer quickstart demonstrates how to use the EJB timer service in ${product.name.full}. This example creates a timer service that uses the @Schedule and @Timeout annotations.

The following EJB Timer services are demonstrated:

• @Schedule: Uses this annotation to mark a method to be executed according to the calendar schedule specified in the attributes of the annotation. This example schedules a message to be printed to the server console every 6 seconds.
• @Timeout: Uses this annotation to mark a method to execute when a programmatic timer goes off. This example sets the timer to go off every 3 seconds, at which point the method prints a message to the server console.

System Requirements

The application this project produces is designed to be run on ${product.name.full} ${product.version} or later.

All you need to build this project is ${build.requirements}. See Configure Maven for ${product.name} ${product.version} to make sure you are configured correctly for testing the quickstarts.

Use of ${jboss.home.name}

In the following instructions, replace ${jboss.home.name} with the actual path to your ${product.name} installation. The installation path is described in detail here: Use of ${jboss.home.name} and JBOSS_HOME Variables.

Start the Server

1. Open a command prompt and navigate to the root of the ${product.name} directory.

2. The following shows the command line to start the server:

    For Linux:   ${jboss.home.name}/bin/standalone.sh
    For Windows: ${jboss.home.name}\bin\standalone.bat
   

Build and Deploy the Quickstart

1. Make sure you have started the ${product.name} server as described above.

2. Open a command prompt and navigate to the root directory of this quickstart.

3. Type this command to build and deploy the archive:

    mvn clean install wildfly:deploy
   

This will deploy target/${project.artifactId}.war to the running instance of the server.

Access the Application

This application only prints messages to stdout. To see it working, check the server log. You should see similar output:

INFO  [stdout] (EJB default - 10) ScheduleExample.doWork() invoked at 2014.11.25 AD at 11:57:12 EST
INFO  [stdout] (EJB default - 2) TimeoutExample.scheduler() EJB timer service timeout at 2014.11.25 AD at 11:57:12 EST
INFO  [stdout] (EJB default - 4) TimeoutExample.scheduler() EJB timer service timeout at 2014.11.25 AD at 11:57:15 EST
INFO  [stdout] (EJB default - 3) TimeoutExample.scheduler() EJB timer service timeout at 2014.11.25 AD at 11:57:18 EST
INFO  [stdout] (EJB default - 5) ScheduleExample.doWork() invoked at 2014.11.25 AD at 11:57:18 EST
INFO  [stdout] (EJB default - 7) TimeoutExample.scheduler() EJB timer service timeout at 2014.11.25 AD at 11:57:21 EST
INFO  [stdout] (EJB default - 9) TimeoutExample.scheduler() EJB timer service timeout at 2014.11.25 AD at 11:57:24 EST
INFO  [stdout] (EJB default - 6) ScheduleExample.doWork() invoked at 2014.11.25 AD at 11:57:24 EST
INFO  [stdout] (EJB default - 8) TimeoutExample.scheduler() EJB timer service timeout at 2014.11.25 AD at 11:57:27 EST
INFO  [stdout] (EJB default - 1) ScheduleExample.doWork() invoked at 2014.11.25 AD at 11:57:30 EST
INFO  [stdout] (EJB default - 10) TimeoutExample.scheduler() EJB timer service timeout at 2014.11.25 AD at 11:57:30 EST
INFO  [stdout] (EJB default - 2) TimeoutExample.scheduler() EJB timer service timeout at 2014.11.25 AD at 11:57:33 EST
INFO  [stdout] (EJB default - 4) ScheduleExample.doWork() invoked at 2014.11.25 AD at 11:57:36 EST
INFO  [stdout] (EJB default - 3) TimeoutExample.scheduler() EJB timer service timeout at 2014.11.25 AD at 11:57:36 EST
INFO  [stdout] (EJB default - 5) TimeoutExample.scheduler() EJB timer service timeout at 2014.11.25 AD at 11:57:39 EST
INFO  [stdout] (EJB default - 7) ScheduleExample.doWork() invoked at 2014.11.25 AD at 11:57:42 EST

Existing threads in the thread pool handle the invocations. They are rotated and the name of the thread that handles the invocation is printed within the parenthesis (EJB Default - #).

Undeploy the Archive

1. Make sure you have started the ${product.name} server as described above.

2. Open a command prompt and navigate to the root directory of this quickstart.

3. When you are finished testing, type this command to undeploy the archive:

    mvn wildfly:undeploy
   

Run the Quickstart in Red Hat JBoss Developer Studio or Eclipse

You can also start the server and deploy the quickstarts or run the Arquillian tests from Eclipse using JBoss tools. For general information about how to import a quickstart, add a ${product.name} server, and build and deploy a quickstart, see Use JBoss Developer Studio or Eclipse to Run the Quickstarts.

Debug the Application

If you want to debug the source code of any library in the project, run the following command to pull the source into your local repository. The IDE should then detect it.

    mvn dependency:sources