public int purge() {
if (tasks.isEmpty()) {
return 0;
}
// callers are synchronized
tasks.deletedCancelledNumber = 0;
tasks.deleteIfCancelled();
return tasks.deletedCancelledNumber;
}
private void insertTask(TimerTask newTask) {
// callers are synchronized
tasks.insert(newTask);
this.notify();
}
/** Cancels timer. */
public synchronized void cancel() {
cancelled = true;
tasks.reset();
this.notify();
}
/** 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;
}
}
}
}
}
