Sometimes, we need schedule jobs dynamically. This requires us to use Quartz scheduler in a programming way rather than a static XML configuration way. I'll show in this post about how to do it with a simple example.
Environment
Java 8
Maven 3
Spring 3.2.3
Quartz 2.2.2
SFL4J 1.7.9 (to show Quartz start up information)
Scenario
We need schedule a report generation task for different departments in an organisation. The task is doing the same thing for different departments but needs to be run at different time, and it collects different data from database for different departments. Suppose sales department's report is to be generated at 7:00 am everyday, marketing department's report is to be generated at 8:00 am on Monday every week and engineering department's report is to be generated at 6:00 pm on the last Friday of every month.
It would be a little difficult to configure the tasks in Spring XML file, because it would be tricky to tell the XML file which department it is. Fortunately, Quartz allows us to use a programming way to schedule the task dynamically.
Implementation
The project configuration is as below.
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- Transaction dependency is required with Quartz integration -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- Quartz framework -->
<dependency>
<groupId>org.quartz-scheduler</groupId>
<artifactId>quartz</artifactId>
<version>${quartz.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${slf4j.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>${slf4j.version}</version>
</dependency>
</dependencies>
<properties>
<spring.version>3.2.3.RELEASE</spring.version>
<quartz.version>2.2.1</quartz.version>
<slf4j.version>1.7.9</slf4j.version>
</properties>
To make it simple here, the task is just print out an information on the console. The task class is as below. the department name is retrieved from the JobDataMap and can be used in the report generation.
public class GenerateReportTask extends QuartzJobBean {
public static final String DEPARTMENT = "DEPARTMENT";
@Override
protected void executeInternal(JobExecutionContext jobExecutionContext) throws JobExecutionException {
JobDataMap dataMap = jobExecutionContext.getMergedJobDataMap();
String department = dataMap.getString(DEPARTMENT);
System.out.println("[" + new Date() + "] Generating report for department " + department);
}
}
A QuartzScheduler class is used to schedule the task dynamically. The schedule CRON expressions are stored in a schedules map and the map is initialised in init() method. The init() method will be called when Spring initialise the QuartzScheduler bean.
public class QuartzScheduler {
private Department[] departments = {Department.ENGINEER, Department.MARKETING, Department.SALES};
private Map schedules = new HashMap();
public void init() {
schedules.put(Department.ENGINEER, "0 0 6 ? * 6L");
schedules.put(Department.MARKETING, "0 0 8 ? * 2");
schedules.put(Department.SALES, "0 0 7 * * ?");
for (Department department : departments) {
schedule(department);
}
}
private enum Department {
SALES, MARKETING, ENGINEER
}
}
In the QuartzScheduler class, an instance of org.quartz.Scheduler class will be injected by Spring, it is the real Quartz scheduler to schedule the tasks. And the schedule() method is using Quartz's static method newJob() and newTrigger() to create the jobDetail and Trigger instances, then add the trigger to the scheduler. You might notice that we put the department name into the JobDataMap. As mentioned above, the department name will be used in the GenerateReportTask class.
public class QuartzScheduler {
private Scheduler scheduler;
...
private void schedule(Department department) {
JobDetail job = newJob(GenerateReportTask.class)
.withIdentity(department.toString(), "reportgen")
.build();
job.getJobDataMap().put(GenerateReportTask.DEPARTMENT, department.toString());
Trigger trigger = newTrigger()
.withIdentity(department.toString(), "reportgen")
.withSchedule(cronSchedule(schedules.get(department)))
.forJob(job).build();
try {
scheduler.scheduleJob(job, trigger);
} catch (SchedulerException e) {
e.printStackTrace();
}
}
...
}
Finally, the Spring XML configuration file contains the bean definition of the QuartzScheduler class and the Spring SchedulerFactoryBean bean to create the real Quartz scheduler instance.
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="quartzScheduler"
class="com.geekspearls.quartz.example2.QuartzScheduler"
init-method="init">
<property name="scheduler" ref="scheduler"/>
</bean>
<bean id="scheduler"
class="org.springframework.scheduling.quartz.SchedulerFactoryBean"/>
</beans>
And the Java application class to test our code.
public class Example2 {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext-quartz2.xml");
System.out.println("Application started [" + new Date() + "] ");
}
}
A complete code can be found on my GitHub here. In order to demo the example, I put the schedules a much shorter period as below.
schedules.put(Department.ENGINEER, "10 * * * * ?");
schedules.put(Department.MARKETING, "30 * * * * ?");
schedules.put(Department.SALES, "50 * * * * ?");
Run the Example2 class as a Java application and you can see the tasks are running at scheduled time on the console. I hope you enjoy it.
