/** The main timer loop. (See class comment.) */
private void mainLoop() {
while (true) {
try {
TimerTask task;
boolean taskFired;
synchronized (queue) {
// Wait for queue to become non-empty
// But no more than timeout value.
while (queue.isEmpty() && queue.newTasksMayBeScheduled) {
queue.wait(THREAD_TIMEOUT);
if (queue.isEmpty()) {
break;
}
}
if (queue.isEmpty()) break; // Queue is empty and will forever remain; die
// Handle a possible change of the user clock
queue.checkUserClockChange();
// Queue nonempty; look at first evt and do the right thing
long currentTime, executionTime;
task = queue.getMin();
synchronized (task.lock) {
if (task.state == TimerTask.CANCELLED) {
queue.removeMin();
continue; // No action required, poll queue again
}
currentTime = Timer.monotonicTimeMillis();
executionTime = task.nextExecutionTime;
if (taskFired = (executionTime <= currentTime)) {
if (task.period == 0) { // Non-repeating, remove
queue.removeMin();
task.state = TimerTask.EXECUTED;
} else { // Repeating task, reschedule
queue.rescheduleMin(
task.period < 0 ? currentTime - task.period : executionTime + task.period);
}
}
}
if (!taskFired) { // Task hasn't yet fired; wait
long timeout = executionTime - currentTime;
if (queue.hasUserClockTasks() && timeout > Timer.USER_CLOCK_CHECK_PERIOD) {
timeout = Timer.USER_CLOCK_CHECK_PERIOD;
}
queue.wait(timeout);
}
}
if (taskFired) { // Task fired; run it, holding no locks
try {
task.run();
} catch (Exception e) {
// Cancel tasks that cause exceptions
task.cancel();
}
}
} catch (InterruptedException e) {
}
}
}
/** Schedules the start and end tasks of the calendar item. */
public void scheduleTasks() {
if (!executeNow) {
timer.schedule(startTask, startDate);
} else {
startTask.run();
}
timer.schedule(endTask, endDate);
}
public void expire() {
if (updateState(ST_INIT, ST_EXPIRED)) {
try {
task.run(this);
} catch (Throwable t) {
parent.logger.warning(
"An exception was thrown by " + TimerTask.class.getSimpleName() + ".", t);
}
}
}
public void expire() {
if (!state.compareAndSet(ST_INIT, ST_EXPIRED)) {
return;
}
try {
task.run(this);
} catch (Throwable t) {
if (logger.isWarnEnabled()) {
logger.warn("An exception was thrown by " + TimerTask.class.getSimpleName() + '.', t);
}
}
}
/**
* Executes example.
*
* @param args Command line arguments, none required.
* @throws GridException If example execution failed.
*/
public static void main(String[] args) throws Exception {
Timer timer = new Timer("priceBars");
// Start grid.
final Grid g = GridGain.start("examples/config/example-streamer.xml");
System.out.println();
System.out.println(">>> Streaming price bars example started.");
try {
TimerTask task = scheduleQuery(g, timer);
streamData(g);
// Force one more run to get final results.
task.run();
timer.cancel();
// Reset all streamers on all nodes to make sure that
// consecutive executions start from scratch.
g.compute()
.broadcast(
new Runnable() {
@Override
public void run() {
if (!ExamplesUtils.hasStreamer(g, "priceBars"))
System.err.println(
"Default streamer not found (is example-streamer.xml "
+ "configuration used on all nodes?)");
else {
GridStreamer streamer = g.streamer("priceBars");
System.out.println("Clearing bars from streamer.");
streamer.reset();
}
}
})
.get();
} finally {
GridGain.stop(true);
}
}
/** This method will be launched on separate thread for each Timer object. */
@Override
public void run() {
while (true) {
final TimerTask task;
synchronized (this) {
// need to check cancelled inside the synchronized block
if (cancelled) {
return;
}
if (tasks.isEmpty()) {
if (finished) {
return;
}
// no tasks scheduled -- sleep until any task appear
try {
this.wait();
} catch (InterruptedException ignored) {
}
continue;
}
long currentTime = System.currentTimeMillis();
task = tasks.minimum();
long timeToSleep;
synchronized (task.lock) {
if (task.cancelled) {
tasks.delete(0);
continue;
}
// check the time to sleep for the first task scheduled
timeToSleep = task.when - currentTime;
}
if (timeToSleep > 0) {
// sleep!
try {
this.wait(timeToSleep);
} catch (InterruptedException ignored) {
}
continue;
}
// no sleep is necessary before launching the task
synchronized (task.lock) {
int pos = 0;
if (tasks.minimum().when != task.when) {
pos = tasks.getTask(task);
}
if (task.cancelled) {
tasks.delete(tasks.getTask(task));
continue;
}
// set time to schedule
task.setScheduledTime(task.when);
// remove task from queue
tasks.delete(pos);
// set when the next task should be launched
if (task.period >= 0) {
// this is a repeating task,
if (task.fixedRate) {
// task is scheduled at fixed rate
task.when = task.when + task.period;
} else {
// task is scheduled at fixed delay
task.when = System.currentTimeMillis() + task.period;
}
// insert this task into queue
insertTask(task);
} else {
task.when = 0;
}
}
}
boolean taskCompletedNormally = false;
try {
task.run();
taskCompletedNormally = true;
} finally {
if (!taskCompletedNormally) {
synchronized (this) {
cancelled = true;
}
}
}
}
}
