/**
* Private method that determines whether a given task should be re-tried based on the given
* {@code Throwable} that caused failure. If this returns {@code true} then the task should be
* re-tried. Otherwise, the task should be dropped.
*/
private boolean shouldRetry(ScheduledTaskImpl task, Throwable t) {
// NOTE: as a first-pass implementation this simply instructs the
// caller to try again if retry is requested, but other strategies
// (like the number of times re-tried) might be considered later
if ((t instanceof ExceptionRetryStatus) && (((ExceptionRetryStatus) t).shouldRetry())) {
return true;
}
// we're not re-trying the task, so log that it's being dropped
if (logger.isLoggable(Level.WARNING)) {
if (task.isRecurring()) {
logger.logThrow(
Level.WARNING,
t,
"skipping a recurrence of "
+ "a task that failed with a non-retryable "
+ "exception: {0}",
task);
} else {
logger.logThrow(
Level.WARNING,
t,
"dropping a task that " + "failed with a non-retryable exception: {0}",
task);
}
}
return false;
}
/** {@inheritDoc} */
public void run() {
logger.log(Level.FINE, "Starting a consumer for transactions");
notifyThreadJoining();
try {
while (true) {
// wait for the next task, at which point we may get
// interrupted and should therefore return
ScheduledTaskImpl task = (ScheduledTaskImpl) (backingQueue.getNextTask(true));
// run the task, checking if it completed
if (executeTask(task, false, true)) {
// if it's a recurring task, schedule the next run
if (task.isRecurring()) {
long nextStart = task.getStartTime() + task.getPeriod();
task = new ScheduledTaskImpl(task, nextStart);
backingQueue.addTask(task);
}
// if it has dependent tasks, schedule the next one
TaskQueueImpl queue = (TaskQueueImpl) (task.getTaskQueue());
if (queue != null) {
queue.scheduleNextTask();
}
}
}
} catch (InterruptedException ie) {
if (logger.isLoggable(Level.FINE)) {
logger.logThrow(Level.FINE, ie, "Consumer is finishing");
}
} catch (Exception e) {
// this should never happen, since running the task should
// never throw an exception that isn't handled
logger.logThrow(Level.SEVERE, e, "Fatal error for consumer");
} finally {
notifyThreadLeaving();
}
}