JBoss.orgCommunity Documentation
Job scheduler defines a job to execute a given number of times during a given period. It is a a software application that is in charge of unattended background executions, commonly known for historical reasons as batch processing.
Today's job schedulers typically provide a graphical user interface and a single point of control for definition and monitoring of background executions in a distributed network of computers. Increasingly job schedulers are required to orchestrate the integration of real-time business activities with traditional background IT processing, across different operating system platforms and business application environments.
Some features that may be found in a job scheduler include:
Continuously automatic monitoring of jobs and completion notification
Event-driven job scheduling
Performance monitoring
Report scheduling
Jobs are scheduled to run when a given Trigger occurs. Triggers can be created with nearly any combination of the following directives:
at a certain time of day (to the millisecond)
on certain days of the week
on certain days of the month
on certain days of the year
not on certain days listed within a registered Calendar (such as business holidays)
repeated a specific number of times
repeated until a specific time/date
repeated indefinitely
repeated with a delay interval
Jobs are given names by their creator and can also be organized into named groups. Triggers may also be given names and placed into groups, in order to easily organize them within the scheduler. Jobs can be added to the scheduler once, but registered with multiple Triggers. Within a J2EE environment, Jobs can perform their work as part of a distributed (XA) transaction.
Kernel leverages Quartz for its scheduler
service and wraps org.quartz.Scheduler in
org.exoplatform.services.scheduler.impl.QuartzSheduler
for easier service wiring and configuration like any other services. To
work with Quartz in Kernel, you'll mostly work with
org.exoplatform.services.scheduler.JobSchedulerService
(implemented by
org.exoplatform.services.scheduler.impl.JobSchedulerServiceImpl.
To use JobSchedulerService, you can
configure it as a component in the configuration.xml. Because
JobSchedulerService requires
QuartzSheduler and
QueueTasks, you also have to configure these two
components.
<?xml version="1.0" encoding="UTF-8"?>
<configuration
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.exoplaform.org/xml/ns/kernel_1_0.xsd http://www.exoplaform.org/xml/ns/kernel_1_0.xsd"
xmlns="http://www.exoplaform.org/xml/ns/kernel_1_0.xsd">
<component>
<type>org.exoplatform.services.scheduler.impl.QuartzSheduler</type>
</component>
<component>
<type>org.exoplatform.services.scheduler.QueueTasks</type>
</component>
<component>
<key>org.exoplatform.services.scheduler.JobSchedulerService</key>
<type>org.exoplatform.services.scheduler.impl.JobSchedulerServiceImpl</type>
</component>
</configuration>We will work with JobSchedulerService by
creating a sample project and use GateIn-3.1.0-GA for testing.
Firstly, create a project:
mvn archetype:generate //.... Choose version: 1: 1.0 2: 1.0-alpha-1 3: 1.0-alpha-2 4: 1.0-alpha-3 5: 1.0-alpha-4 Choose a number: : 1 Define value for property 'groupId': : org.exoplatform.samples Define value for property 'artifactId': : exo.samples.scheduler Define value for property 'version': 1.0-SNAPSHOT: 1.0-SNAPSHOT Define value for property 'package': org.exoplatform.samples: jar Confirm properties configuration: groupId: org.exoplatform.samples artifactId: exo.samples.scheduler version: 1.0-SNAPSHOT package: jar Y: Y
Choose version as 1.0-SNAPSHOT, groupId as org.exoplatform.samples, artifactId as exo.samples.scheduler and package as jar. Edit the pom.xml as following:
<project
xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<artifactId>exo.portal.parent</artifactId>
<groupId>org.exoplatform.portal</groupId>
<version>3.1.0-GA</version>
</parent>
<groupId>org.exoplatform.samples</groupId>
<artifactId>exo.samples.scheduler</artifactId>
<version>1.0-SNAPSHOT</version>
<name>eXo Samples For Scheduler</name>
<description>eXo Samples Code For Scheduler</description>
<dependencies>
<dependency>
<groupId>quartz</groupId>
<artifactId>quartz</artifactId>
<version>1.5.2</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>picocontainer</groupId>
<artifactId>picocontainer</artifactId>
<version>1.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.exoplatform.kernel</groupId>
<artifactId>exo.kernel.commons</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.exoplatform.kernel</groupId>
<artifactId>exo.kernel.component.common</artifactId>
<scope>provided</scope>
</dependency>
</dependencies>
</project>After that, create a eclipse project and then import into eclipse:
mvn eclipse:eclipse
We'll work with this project all the time through samples.
See how it works on Quartz at: http://www.quartz-scheduler.org/docs/tutorial/TutorialLesson03.html
Create a package in created project: conf/portal and add a configuration configuration.xml as follows:
<?xml version="1.0" encoding="UTF-8"?>
<configuration
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.exoplaform.org/xml/ns/kernel_1_0.xsd http://www.exoplaform.org/xml/ns/kernel_1_0.xsd"
xmlns="http://www.exoplaform.org/xml/ns/kernel_1_0.xsd">
<component>
<type>org.exoplatform.services.scheduler.impl.QuartzSheduler</type>
</component>
<component>
<type>org.exoplatform.services.scheduler.QueueTasks</type>
</component>
<component>
<key>org.exoplatform.services.scheduler.JobSchedulerService</key>
<type>org.exoplatform.services.scheduler.impl.JobSchedulerServiceImpl</type>
</component>
<component>
<type>org.exoplatform.samples.scheduler.StartableScheduler</type>
</component>
</configuration>Note: You can see a component: StartableSheduler to be defined. It's a component startable when portal containers are initialized.
package org.exoplatform.samples.scheduler;
import java.util.Date;
import org.exoplatform.samples.scheduler.jobs.DumbJob;
import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.log.Log;
import org.exoplatform.services.scheduler.impl.QuartzSheduler;
import org.picocontainer.Startable;
import org.quartz.JobDetail;
import org.quartz.Scheduler;
import org.quartz.SchedulerException;
import org.quartz.Trigger;
import org.quartz.TriggerUtils;
/**
* Created by The eXo Platform SAS
* Author : eXoPlatform
* exo@exoplatform.com
* Jul 1, 2010
*/
public class StartableScheduler implements Startable {
private static final Log LOG = ExoLogger.getLogger(StartableScheduler.class);
public StartableScheduler(QuartzSheduler quartzScheduler) throws SchedulerException {
LOG.info("Init StartableScheduler");
JobDetail jobDetail = new JobDetail("myJob",
Scheduler.DEFAULT_GROUP,
DumbJob.class);
Trigger trigger = TriggerUtils.makeImmediateTrigger(3, 5000);
trigger.setStartTime(new Date());
trigger.setName("myTrigger");
Scheduler scheduler = quartzScheduler.getQuartzSheduler();
scheduler.scheduleJob(jobDetail, trigger);
}
@Override
public void start() {
// TODO Auto-generated method stub
}
@Override
public void stop() {
// TODO Auto-generated method stub
}
}DumbJob is defined as a job:
package org.exoplatform.samples.scheduler.jobs;
import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.log.Log;
import org.quartz.Job;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
/**
* DumbJob.java
*
* @author <a href="http://hoatle.net">hoatle (hoatlevan at gmail dot com)</a>
* @since Jul 1, 2010
* @copyright eXo SAS
*/
public class DumbJob implements Job {
private static final Log LOG = ExoLogger.getLogger(DumbJob.class);
@Override
public void execute(JobExecutionContext context) throws JobExecutionException {
LOG.info("DumbJob is executing!");
}
}mvn clean install the project. Copy jar file to lib in tomcat bundled with GateIn-3.1.0-GA. Run bin/gatein.sh to see the DumbJob executed on the terminal when portal containers are initialized.
Job Service Scheduler (JSS) is used in many eXo products such as Social, DMS, WCM, KS and CS.
For example: It is used in Schedule lifecycle in DMS.
Also, it is used for News Letter Email Job in ECM, Reminder Job for calendar and History Job for chat in CS, Auto-count Active Users in KS.
By using Job Scheduler Service in eXo kernel, many kinds of job can be configured to run. You can addPeriodJob, addCronJob, addGlobalJobListener, addJobListener and many more. Just write a job (a class implements Job interface of quartz library and config plugin for JobSchedulerService and you're done.
It's very useful to use Job Scheduler to create schedules for a lot of work, especially if they are spread across multiple machines. It's a tool to make that task a lot easier. Job Schedule is also widely used in almost eXo products such as: WCM, DMS, KS, CS, Social thanks to its benefits and advantages.
The Job Scheduler provides automatically log files for running programs
The execution status of programs is automatically checked and an administrator will receive protocols by eMail
The sequence of job starts can be organized depending on their execution status
Job Schedulers are controlled by a graphical user interface
Job Schedulers can be used to create complex job chains and job dependencies
Also, a wide variety of enterprise applications can take advantage of job schedulers. Job schedulers can enhance the functionality of enterprise applications as well as simplify their design. Furthermore, job scheduling components allow software development teams to focus on their applications and not on the intricate details of scheduling. By using server-side components, software teams can reduce development costs and bring their applications to market sooner.
To further understand about Job Scheduler, you can refer the following links: