Quartz

Hello World

This is a very simple hello world using RAMJobStore.

Files

Directory Layout

.
├── pom.xml
└── src
    └── main
        ├── java
        │   └── biz
        │       └── tugay
        │           ├── MyQuartzJob.java
        │           └── QuartzHelloWorld.java
        └── resources
            └── quartz.properties

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>biz.tugay</groupId>
    <artifactId>my-quartz</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.quartz-scheduler</groupId>
            <artifactId>quartz</artifactId>
            <version>2.3.2</version>
        </dependency>
    </dependencies>
</project>

quartz.properties

org.quartz.scheduler.instanceName = My-Scheduler-Instance
org.quartz.threadPool.threadCount = 1
org.quartz.jobStore.class = org.quartz.simpl.RAMJobStore

MyQuartzJob.java

import org.quartz.Job;
import org.quartz.JobExecutionContext;

public class MyQuartzJob implements Job {
    public void execute(JobExecutionContext context) {
        System.out.println("hello world");
    }
}

QuartzHelloWorld.java

import org.quartz.*;
import org.quartz.impl.StdSchedulerFactory;

public class QuartzHelloWorld {
    public static void main(String[] args) throws Exception {
        new QuartzHelloWorld().run();
    }

    void run() throws Exception {
        Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();

        JobDetail job = JobBuilder.newJob(MyQuartzJob.class)
                .withIdentity("job1", "group1")
                .build();

        Trigger trigger = TriggerBuilder.newTrigger()
                .withIdentity("trigger1", "group1")
                .startNow()
                .withSchedule(SimpleScheduleBuilder
                        .simpleSchedule()
                        .withIntervalInMilliseconds(2000)
                        .repeatForever())
                .build();

        scheduler.scheduleJob(job, trigger);

        scheduler.start();
        Thread.sleep(5000);
        scheduler.shutdown();
    }
}

Example with JobStoreTX

Making the above example work with a PostgreSQL database. Create tables using the scripts here. Database I used in this example is named my-quartz.

Files

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>biz.tugay</groupId>
    <artifactId>my-quartz</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.quartz-scheduler</groupId>
            <artifactId>quartz</artifactId>
            <version>2.3.2</version>
        </dependency>
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>42.2.12</version>
        </dependency>
    </dependencies>
</project>

quartz.properties

org.quartz.scheduler.instanceName=My-Scheduler-Instance
org.quartz.threadPool.threadCount=1
org.quartz.jobStore.class=org.quartz.impl.jdbcjobstore.JobStoreTX

org.quartz.jobStore.dataSource=myDS

org.quartz.jobStore.driverDelegateClass=org.quartz.impl.jdbcjobstore.PostgreSQLDelegate
org.quartz.dataSource.myDS.driver=org.postgresql.Driver
org.quartz.dataSource.myDS.URL=jdbc:postgresql://localhost:5432/my-quartz
org.quartz.dataSource.myDS.user=postgres
org.quartz.dataSource.myDS.password=""

QuartzHelloWorld.java

import org.quartz.*;
import org.quartz.impl.StdSchedulerFactory;

public class QuartzHelloWorld {
    public static void main(String[] args) throws Exception {
        new QuartzHelloWorld().run();
    }

    void run() throws Exception {
        Scheduler scheduler = StdSchedulerFactory.getDefaultScheduler();

        JobKey jobKey = new JobKey("job1", "group1");

        // You can not keep scheduling the same job since job now lives in DB
        if (!scheduler.checkExists(jobKey)) {
            JobDetail job = JobBuilder.newJob(MyQuartzJob.class)
                    .withIdentity(jobKey)
                    .build();

            Trigger trigger = TriggerBuilder.newTrigger()
                    .withIdentity("trigger1", "group1")
                    .startNow()
                    .withSchedule(SimpleScheduleBuilder.simpleSchedule()
                        .withIntervalInMilliseconds(2000)
                        .withMisfireHandlingInstructionNextWithExistingCount()
                        .repeatForever())
                    .build();

            scheduler.scheduleJob(job, trigger);
        }

        scheduler.start();
        Thread.sleep(5000);
        scheduler.shutdown();
    }
}

Terminology

Scheduler
The main API for interacting with the scheduler.
Job
An interface to be implemented by components that you wish to have executed by the Scheduler.
JobDetail
Used to define instances of Jobs.
JobBuilder
Used to define/build JobDetail instances, which define instances of Jobs.
Trigger
A component that defines the schedule upon which a given Job will be executed.
TriggerBuilder
Used to define/build Trigger instances.

References

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