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 6 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.
- You can add
<concurrency-allowed>true</concurrency-allowed>in jobs.xml. - 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-1.7.26
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>2.2.1</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>2.2.2-SNAPSHOT</version>
</dependency>
Building
mvn clean package
mvn javadoc:javadoc
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.
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