Posticipate Quartz expression to the next weekday

问题

I need to create a Quartz cron expression that fires every 10th day of the month if it is a weekday, otherwise fires to the next day or the day after the next.

E.g. August 10th 2014 is Sunday, fire Monday 11th
E.g. September 10th 2014 is Wednesiday, fire Wednesday 10th
E.g. January 10th 2015 is Saturday, fire Monday 12th

I highlighted the third case: I tried 0 0 0 10W * ? as expression but it fires Friday Jan 8th 2015. I need it to be fired later.

How do I tell Quartz to? I wanted to make three expressions, e.g. "the 10th if it is a weekday", "11th if it is a monday" and "12th if it is a monday" but I can't combine day-of-month and day-of-week fields (I always get an Invalid cron expression error)

回答1:

I don't think you can do that with a simple cron expression, but you can use the following solution.

First schedule your Job with a classic Cron Trigger

    CronScheduleBuilder sh = cronSchedule("0 0 0 10 * ?");
    TriggerBuilder<Trigger> tb = newTrigger()
        .withSchedule(sh)
        .withIdentity("MyTrigger");

And schedule your Trigger. Then create a Quartz TriggerListener that implements your mecanism

    public class MyTriggerListener implements TriggerListener {
         [...]

         @Override
         public void vetoJobExecution(Trigger trigger, JobExecutionContext context) {

              // You check if it is your Cron Trigger
              if ("MyTrigger".equals(trigger.getKey.getName()) {
                   Calendar cal = Calendar.getInstance();

                   // If current date is sunday, then another one-time trigger 
                   //   is created to delay the job firing
                   if (Calendar.SUNDAY.equals(cal.get(Calendar.DAY_OF_WEEK))) {

                        cal.add(Calendar.DATE, 1); // One day later

                        TriggerBuilder<Trigger> tb = newTrigger()
                            .startAt(cal.getTime());
                            .withIdentity("MyTrigger_delayed");
                            .forJob(context.getJobDetail());

                        // TODO schedule it in Quartz the way you want
                        // like : scheduler.scheduleJob(tb.build());

                        return true; // The current fire is vetoed
                   }

                   // If current date is saturday, then another one-time trigger 
                   //   is created to delay the job firing
                   else if (Calendar.SATURDAY.equals(cal.get(Calendar.DAY_OF_WEEK))) {

                        cal.add(Calendar.DATE, 2); // Two day later

                        TriggerBuilder<Trigger> tb = newTrigger()
                            .startAt(cal.getTime());
                            .withIdentity("MyTrigger_delayed");
                            .forJob(context.getJobDetail());

                        // TODO schedule it in Quartz the way you want
                        // like : scheduler.scheduleJob(tb.build());

                        return true;// The current fire is vetoed
                   } 
                   // If it is a weekday, the job fires normally
                   else {
                        return false;
                   }
              }

              // It is not your Cron Trigger
              return false;
         }
    }

This code implement a mecanism to delayed your job firing to start the job a weekday. You can add this Listener to your Scheduler with

        TriggerListener myTriggerListener = new MyTriggerListener("MyTriggerListener");
        scheduler.getListenerManager().addTriggerListener(myTriggerListener, allTriggers());

来源：https://stackoverflow.com/questions/25115034/posticipate-quartz-expression-to-the-next-weekday

标签

java

scheduled-tasks

quartz-scheduler