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Sundial Sundial

A Lightweight Job Scheduling Framework for Java.

In a Nutshell

Sundial makes adding scheduled jobs to your Java application a walk in the park. Simply define jobs, define triggers, and start the Sundial scheduler.

Long Description

Sundial is a lightweight Java job scheduling framework forked from Quartz (http://www.quartz-scheduler.org/) stripped down to the bare essentials. Sundial also hides the nitty-gritty configuration details of Quartz, reducing the time needed to get a simple RAM job scheduler up and running. Sundial uses a ThreadLocal wrapper for each job containing a HashMap for job key-value pairs. Convenience methods allow easy access to these parameters. JobActions are reusable components that also have access to the context parameters. If you are looking for a hassle-free 100% Java job scheduling framework that is easy to integrate into your applications, look no further.

Features

  • Apache 2.0 license
  • ~150 KB Jar
  • In-memory multi-threaded jobs
  • Define jobs and triggers in jobs.xml
  • or define jobs and triggers via annotations
  • or define jobs and triggers programmatically
  • Cron Triggers
  • Simple Triggers
  • Java 8 and up
  • Depends only on slf4j

Create a Job Class

public class SampleJob extends org.knowm.sundial.Job {

  @Override
  public void doRun() throws JobInterruptException {
    // Do something interesting...
  }
}

...with CronTrigger or SimpleTrigger Annotation

@CronTrigger(cron = "0/5 * * * * ?")
@SimpleTrigger(repeatInterval = 30, timeUnit = TimeUnit.SECONDS)

Start Sundial Job Scheduler

public static void main(String[] args) {

  SundialJobScheduler.startScheduler("org.knowm.sundial.jobs"); // package with annotated Jobs
}

If you need a bigger thread pool (default size is 10) use startScheduler(int threadPoolSize, String annotatedJobsPackageName) instead.

Alternatively, Put an XML File Called jobs.xml on Classpath

<?xml version='1.0' encoding='utf-8'?>
<job-scheduling-data>

	<schedule>

		<!-- job with cron trigger -->
		<job>
			<name>SampleJob3</name>
			<job-class>com.foo.bar.jobs.SampleJob3</job-class>
			<concurrency-allowed>true</concurrency-allowed>
		</job>
		<trigger>
			<cron>
				<name>SampleJob3-Trigger</name>
				<job-name>SampleJob3</job-name>
				<cron-expression>*/15 * * * * ?</cron-expression>
			</cron>
		</trigger>

		<!-- job with simple trigger -->
		<job>
			<name>SampleJob2</name>
			<job-class>com.foo.bar.jobs.SampleJob2</job-class>
			<job-data-map>
				<entry>
					<key>MyParam</key>
					<value>42</value>
				</entry>
			</job-data-map>
		</job>
		<trigger>
			<simple>
				<name>SampleJob2-Trigger</name>
				<job-name>SampleJob2</job-name>
				<repeat-count>5</repeat-count>
				<repeat-interval>5000</repeat-interval>
			</simple>
		</trigger>

	</schedule>

</job-scheduling-data>

Or, Define Jobs and Triggers Manually

SundialJobScheduler.addJob("SampleJob", "org.knowm.sundial.jobs.SampleJob");
SundialJobScheduler.addCronTrigger("SampleJob-Cron-Trigger", "SampleJob", "0/10 * * * * ?");
SundialJobScheduler.addSimpleTrigger("SampleJob-Simple-Trigger", "SampleJob", -1, TimeUnit.SECONDS.toMillis(3));

More Functions

// asynchronously start a job by name
SundialJobScheduler.startJob("SampleJob");

// interrupt a running job
SundialJobScheduler.stopJob("SampleJob");

// remove a job from the scheduler
SundialJobScheduler.removeJob("SampleJob");

// remove a trigger from the scheduler
SundialJobScheduler.removeTrigger("SampleJob-Trigger");

// lock scheduler
SundialJobScheduler.lockScheduler();

// unlock scheduler
SundialJobScheduler.unlockScheduler();

// check if job a running
SundialJobScheduler.isJobRunning("SampleJob");

And many more useful functions. See all here: https://github.com/knowm/Sundial/blob/develop/src/main/java/org/knowm/sundial/SundialJobScheduler.java

Job Data Map

// asynchronously start a job by name with data map
Map<String, Object> params = new HashMap<>();
params.put("MY_KEY", new Integer(660));
SundialJobScheduler.startJob("SampleJob1", params);
// annotate CronTrigger with data map (separate key/values with ":" )
@CronTrigger(cron = "0/5 * * * * ?", jobDataMap = { "KEY_1:VALUE_1", "KEY_2:1000" })
public class SampleJob extends Job {
}
<!-- configure data map in jobs.xml -->
<job>
  <name>SampleJob</name>
  <job-class>org.knowm.sundial.jobs.SampleJob</job-class>
  <job-data-map>
    <entry>
      <key>MyParam</key>
      <value>42</value>
    </entry>
  </job-data-map>
</job>
// access data inside Job
String value1 = getJobContext().get("KEY_1");
logger.info("value1 = " + value1);

Get Organized with Job Actions!

With JobActions, you can encapsule logic that can be shared by different Jobs.

public class SampleJobAction extends JobAction {

  @Override
  public void doRun() {

    Integer myValue = getJobContext().get("MyValue");

    // Do something interesting...
  }
}
// Call the JobAction from inside a Job
getJobContext().put("MyValue", new Integer(123));
new SampleJobAction().run();

Job Termination

To terminate a Job asynchronously, you can call the SundialJobScheduler.stopJob(String jobName) method. The Job termination mechanism works by setting a flag that the Job should be terminated, but it is up to the logic in the Job to decide at what point termination should occur. Therefore, in any long-running job that you anticipate the need to terminate, put the method call checkTerminated() at an appropriate location.

For an example see SampleJob9.java. In a loop within the Job you should just add a call to checkTerminated();.

If you try to shutdown the SundialScheduler and it just hangs, it's probably because you have a Job defined with an infinite loop with no checkTerminated(); call. You may see a log message like: Waiting for Job to shutdown: SampleJob9 : SampleJob9-trigger.

Concurrent Job Execution

By default jobs are not set to concurrently execute. This means if a job is currently running and a trigger is fired for that job, it will skip running the job. In some cases concurrent job execution is desired and there are a few ways to configure it.

  1. You can add <concurrency-allowed>true</concurrency-allowed> in jobs.xml.
  2. You can add it to the Sundial annotations like this: @SimpleTrigger(repeatInterval = 30, timeUnit = TimeUnit.SECONDS, isConcurrencyAllowed = true) Same idea for cron annotation too.

Now go ahead and study some more examples, download the thing and provide feedback.

Getting the Goods

Non-Maven

Download Jar: http://knowm.org/open-source/sundial/sundial-change-log/

Dependencies

  • org.slf4j.slf4j-api-2.0.12

Maven

The Sundial release artifacts are hosted on Maven Central.

Add the Sundial library as a dependency to your pom.xml file:

<dependency>
    <groupId>org.knowm</groupId>
    <artifactId>sundial</artifactId>
    <version>2.3.0</version>
</dependency>

For snapshots, add the following to your pom.xml file:

<repository>
  <id>sonatype-oss-snapshot</id>
  <snapshots/>
  <url>https://oss.sonatype.org/content/repositories/snapshots</url>
</repository>

<dependency>
    <groupId>org.knowm</groupId>
    <artifactId>sundial</artifactId>
    <version>2.3.1-SNAPSHOT</version>
</dependency>

Building

mvn clean package  
mvn javadoc:javadoc
mvn com.spotify.fmt:fmt-maven-plugin:format

Dependency Updates

mvn versions:display-dependency-updates

Cron Expressions in jobs.xml

See the Cron Trigger tutorial over at quartz-scheduler.org. Here are a few examples:

Expression Meaning
0 0 12 * * ? Fire at 12pm (noon) every day
0 15 10 * * ? Fire at 10:15am every day
0 15 10 ? * MON-FRI Fire at 10:15am every Monday, Tuesday, Wednesday, Thursday and Friday
0 0/10 * * * ? Fire every 10 mintes starting at 12 am (midnight) every day

Bugs

Please report any bugs or submit feature requests to Sundial's Github issue tracker.

Continuous Integration

Java CI with Maven on Push