/**
* Stops a running task.
*
* @param taskDefinition the task to be stopped
* @see org.openmrs.scheduler.SchedulerService#shutdownTask(TaskDefinition)
*/
public void shutdownTask(TaskDefinition taskDefinition) throws SchedulerException {
if (taskDefinition != null) {
// Remove the task from the scheduled tasks and shutdown the timer
TimerSchedulerTask schedulerTask = scheduledTasks.remove(taskDefinition.getId());
if (schedulerTask != null) {
schedulerTask
.shutdown(); // Stops the timer and tells the timer task to release its resources
}
// Update task that has been started
taskDefinition.setStarted(false);
saveTask(taskDefinition);
}
}
/**
* Schedule the given task according to the given schedule.
*
* @param taskDefinition the task to be scheduled
* @should should handle zero repeat interval
*/
public Task scheduleTask(TaskDefinition taskDefinition) throws SchedulerException {
Task clientTask = null;
if (taskDefinition != null) {
// Cancel any existing timer tasks for the same task definition
// TODO Make sure this is the desired behavior
// TODO Do we ever want the same task definition to run more than once?
TimerSchedulerTask schedulerTask = scheduledTasks.get(taskDefinition.getId());
if (schedulerTask != null) {
// schedulerTask.cancel();
log.info("Shutting down the existing instance of this task to avoid conflicts!!");
schedulerTask.shutdown();
}
try {
// Create new task from task definition
clientTask = TaskFactory.getInstance().createInstance(taskDefinition);
// if we were unable to get a class, just quit
if (clientTask != null) {
schedulerTask = new TimerSchedulerTask(clientTask);
taskDefinition.setTaskInstance(clientTask);
// Once this method is called, the timer is set to start at the given start time.
// NOTE: We need to adjust the repeat interval as the JDK Timer expects time in
// milliseconds and
// we record by seconds.
long repeatInterval = 0;
if (taskDefinition.getRepeatInterval() != null)
repeatInterval =
taskDefinition.getRepeatInterval() * SchedulerConstants.SCHEDULER_MILLIS_PER_SECOND;
if (taskDefinition.getStartTime() != null) {
// Need to calculate the "next execution time" because the scheduled time is most likely
// in the past
// and the JDK timer will run the task X number of times from the start time until now
// to catch up.
Date nextTime = SchedulerUtil.getNextExecution(taskDefinition);
// Start task at fixed rate at given future date and repeat as directed
log.info("Starting task ... the task will execute for the first time at " + nextTime);
if (repeatInterval > 0) {
// Schedule the task to run at a fixed rate
getTimer(taskDefinition).scheduleAtFixedRate(schedulerTask, nextTime, repeatInterval);
} else {
// Schedule the task to be non-repeating
getTimer(taskDefinition).schedule(schedulerTask, nextTime);
}
} else if (repeatInterval > 0) {
// Start task on repeating schedule, delay for SCHEDULER_DEFAULT_DELAY seconds
log.info(
"Delaying start time by "
+ SchedulerConstants.SCHEDULER_DEFAULT_DELAY
+ " seconds");
getTimer(taskDefinition)
.scheduleAtFixedRate(
schedulerTask, SchedulerConstants.SCHEDULER_DEFAULT_DELAY, repeatInterval);
} else {
// schedule for single execution, starting now
log.info("Starting one-shot task");
getTimer(taskDefinition).schedule(schedulerTask, new Date());
}
// Update task that has been started
log.debug("Registering timer for task " + taskDefinition.getId());
// Add the new timer to the scheduler running task list
scheduledTasks.put(taskDefinition.getId(), schedulerTask);
// Update the timer status in the database
taskDefinition.setStarted(true);
saveTask(taskDefinition);
}
} catch (Exception e) {
log.error("Failed to schedule task " + taskDefinition.getName(), e);
throw new SchedulerException("Failed to schedule task", e);
}
}
return clientTask;
}