Quartz plugin allows your Grails application to schedule jobs to be executed using a specified interval or cron expression. The underlying system uses the Quartz Enterprise Job Scheduler configured via Spring, but is made simpler by the coding by convention paradigm.

To install the latest stable version of the plugin run:

grails install-plugin quartz

To create a new job run the “grails create-job” command and enter the name of the job. Grails will create a new job and place it in the “grails-app/jobs” directory:

class MyJob {
  static triggers = {
    simple repeatInterval: 1000
  }

  def execute(){
    print "Job run!"
  }
}

The above example will call the ‘execute’ method every second.

Currently plugin supports three types of triggers:

• simple trigger — executes once per defined interval (ex. “every 10 seconds”);

• cron trigger — executes job with cron expression (ex. “at 8:00am every Monday through Friday”);

• custom trigeer — your implementation of Trigger interface.

Multiple triggers per job are allowed.

class MyJob {
  static triggers = {
    simple name:'simpleTrigger', startDelay:10000, repeatInterval: 30000, repeatCount: 10
    cron name:'cronTrigger', startDelay:10000, cronExpression: '0/6 * 15 * * ?'
    custom name:'customTrigger', triggerClass:MyTriggerClass, myParam:myValue, myAnotherParam:myAnotherValue
  }

  def execute() {
    println "Job run!"
  }
}

With this configuration job will be executed 11 times with 30 seconds interval with first run in 10 seconds after scheduler startup (simple trigger), also it’ll be executed each 6 second during 15th hour (15:00:00, 15:00:06, 15:00:12, … — this configured by cron trigger) and also it’ll be executed each time your custom trigger will fire.

Three kinds of triggers are supported with the following parameters:

• simple:

  • name — the name that identifies the trigger;

  • startDelay — delay (in milliseconds) between scheduler startup and first job’s execution;

  • repeatInterval — timeout (in milliseconds) between consecutive job’s executions;

  • repeatCount — trigger will fire job execution (1 + repeatCount) times and stop after that (specify 0 here to have one-shot job or -1 to repeat job executions indefinitely);

• cron:

  • name — the name that identifies the trigger;

  • startDelay — delay (in milliseconds) between scheduler startup and first job’s execution;

  • cronExpression — cron expression

• custom:

  • triggerClass — your class which implements Trigger interface;

  • any params needed by your trigger.