Example 5 - Job Misfires

This example is designed to demonstrate concepts related to trigger misfires.

The program will perform the following actions:

• Start up the Quartz Scheduler
• Schedule two jobs, each job will execute the every three seconds, indefinitely
• The jobs will take ten seconds to run (preventing the execution trigger from firing every three seconds)
• Each job has different misfire instructions
• The program will wait 10 minutes so that the two jobs have plenty of time to run
• Shut down the Scheduler

Running the Example

This example can be executed from the examples/example5 directory. There are two out-of-the-box methods for running this example

• example5.sh - A UNIX/Linux shell script
• example5.bat - A Windows Batch file

The Code

The code for this example resides in the package org.quartz.examples.example5.

The code in this example is made up of the following classes:

StatefulDumbJob

StatefulDumbJob is a simple job that prints its execution time and then will wait for a period of time before completing.
The amount of wait time is defined by the job parameter EXECUTION_DELAY. If this job parameter is not passed in, the job will default to a wait time of 5 seconds. The job is also keep its own count of how many times it has executed using a value in its JobDataMap called NUM_EXECUTIONS. Because the class has the PersistJobDataAfterExecution annotation, the execution count is preserved between each execution.

@PersistJobDataAfterExecution
@DisallowConcurrentExecution
public class StatefulDumbJob implements Job {

    public static final String NUM_EXECUTIONS = "NumExecutions";
    public static final String EXECUTION_DELAY = "ExecutionDelay";

    public StatefulDumbJob() {
    }
    public void execute(JobExecutionContext context)
        throws JobExecutionException {
        System.err.println("---" + context.getJobDetail().getKey()
                + " executing.[" + new Date() + "]");

        JobDataMap map = context.getJobDetail().getJobDataMap();

        int executeCount = 0;
        if (map.containsKey(NUM_EXECUTIONS)) {
            executeCount = map.getInt(NUM_EXECUTIONS);
        }

        executeCount++;
        map.put(NUM_EXECUTIONS, executeCount);

        long delay = 5000l;
        if (map.containsKey(EXECUTION_DELAY)) {
            delay = map.getLong(EXECUTION_DELAY);
        }

        try {
            Thread.sleep(delay);
        } catch (Exception ignore) {
        }

        System.err.println("  -" + context.getJobDetail().getKey()
                + " complete (" + executeCount + ").");
    }
}

MisfireExample

The program starts by getting an instance of the Scheduler. This is done by creating a StdSchedulerFactory and then using it to create a scheduler. This will create a simple, RAM-based scheduler because no specific quartz.properties config file telling it to do otherwise is provided.

SchedulerFactory sf = new StdSchedulerFactory();
Scheduler sched = sf.getScheduler();

Job #1 is scheduled to run every 3 seconds indefinitely. An execution delay of 10 seconds is passed into the job:

JobDetail job = newJob(StatefulDumbJob.class)
    .withIdentity("statefulJob1", "group1")
    .usingJobData(StatefulDumbJob.EXECUTION_DELAY, 10000L)
    .build();

SimpleTrigger trigger = newTrigger()
    .withIdentity("trigger1", "group1")
    .startAt(startTime)
    .withSchedule(simpleSchedule()
            .withIntervalInSeconds(3)
            .repeatForever())
    .build();

sched.scheduleJob(job, trigger);

Job #2 is scheduled to run every 3 seconds indefinitely. An execution delay of 10 seconds is passed into the job:

job = newJob(StatefulDumbJob.class)
            .withIdentity("statefulJob2", "group1")
            .usingJobData(StatefulDumbJob.EXECUTION_DELAY, 10000L)
            .build();

        trigger = newTrigger()
            .withIdentity("trigger2", "group1")
            .startAt(startTime)
            .withSchedule(simpleSchedule()
                    .withIntervalInSeconds(3)
                    .repeatForever()
                    .withMisfireHandlingInstructionNowWithExistingCount()) // set misfire instruction
            .build();

Note: The trigger for job #2 is set with a misfire instruction that will cause it to reschedule with the existing repeat count. This policy forces quartz to refire the trigger as soon as possible. Job #1 uses the default “smart” misfire policy for simple triggers, which causes the trigger to fire at it’s next normal execution time.

The scheduler is then started.

sched.start();

To let the program have an opportunity to run the job, we then sleep for ten minutes (600 seconds)

Thread.sleep(600L * 1000L);

Finally, we will gracefully shutdown the scheduler:

sched.shutdown(true);

Note: passing true into the shutdown message tells the Quartz Scheduler to wait until all jobs have completed running before returning from the method call.