Developer Materials

ejb-timer

  • Author:
    Original Author
    Ondrej Zizka <ozizka@redhat.com>
  • Published: 2017-12-14
  • Level:
    Difficulty Level
    Beginner
  • Technologies:
    Technologies Used
    EJB Timer
  • Target Product:

    Body
    The ejb-timer quickstart demonstrates how to use the EJB timer service @Schedule and @Timeout annotations with JBoss EAP.

    What is it?

    The ejb-timer quickstart demonstrates how to use the EJB timer service in JBoss Enterprise Application Platform Server. 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 JBoss Enterprise Application Platform Server 7.2 or later.

    All you need to build this project is Java 8.0 (Java SDK 1.8) or later and Maven 3.3.1 or later. See Configure Maven to Build and Deploy the Quickstarts to make sure you are configured correctly for testing the quickstarts.

    Use of EAP_HOME

    In the following instructions, replace EAP_HOME with the actual path to your JBoss EAP installation. The installation path is described in detail here: Use of EAP_HOME and JBOSS_HOME Variables.

    Start the JBoss EAP Standalone Server

    1. Open a terminal and navigate to the root of the JBoss EAP directory.

    2. Start the JBoss EAP server with the default profile by typing the following command.

      $ EAP_HOME/bin/standalone.sh 
      Note
      For Windows, use the EAP_HOME\bin\standalone.bat script.

    Build and Deploy the Quickstart

    1. Make sure you start the JBoss EAP server as described above.

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

    3. Type the following command to build the artifacts.

      $ mvn clean package wildfly:deploy

    This deploys the ejb-timer/target/ejb-timer.war to the running instance of the server.

    You should see a message in the server log indicating that the archive deployed successfully.

    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 Quickstart

    When you are finished testing the quickstart, follow these steps to undeploy the archive.

    1. Make sure you start the JBoss EAP server as described above.

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

    3. 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 in Red Hat JBoss Developer Studio or from Eclipse using JBoss tools. For general information about how to import a quickstart, add a JBoss EAP 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