@Override
    public void execute(JobExecutionContext jobExecutionContext) throws JobExecutionException {
        JobDataMap dataMap = jobExecutionContext.getJobDetail().getJobDataMap();
        CronTrigger cronEventTrigger = (CronTrigger) dataMap.get("trigger");
        if (log.isDebugEnabled()) {
            log.debug("Running Trigger Job '" + cronEventTrigger.getId() + "'");
        }
        cronEventTrigger.sendEvent();
    }
This will be called only once and this can be used to release
the acquired resources for processing.
This will be called before shutting down the system.
modules/siddhi-core/src/main/java/io/siddhi/core/trigger/CronTrigger.java