A java.util.concurrent.ScheduledExecutorService interface is a subinterface of ExecutorService interface, and supports future and/or periodic execution of tasks.
ScheduledExecutorService Methods
| Sr.No. | Method & Description |
|---|---|
| 1 | <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit)Creates and executes a ScheduledFuture that becomes enabled after the given delay. |
| 2 | ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit)Creates and executes a one-shot action that becomes enabled after the given delay. |
| 3 | ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit)Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period; that is executions will commence after initialDelay then initialDelay+period, then initialDelay + 2 * period, and so on. |
| 4 | ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit)Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given delay between the termination of one execution and the commencement of the next. |
Example
The following TestThread program shows usage of ScheduledExecutorService interface in thread based environment.
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
public class TestThread {
public static void main(final String[] arguments) throws InterruptedException {
final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
final ScheduledFuture<?> beepHandler =
scheduler.scheduleAtFixedRate(new BeepTask(), 2, 2, TimeUnit.SECONDS);
scheduler.schedule(new Runnable() {
@Override
public void run() {
beepHandler.cancel(true);
scheduler.shutdown();
}
}, 10, TimeUnit.SECONDS);
}
static class BeepTask implements Runnable {
public void run() {
System.out.println("beep");
}
}
}This will produce the following result.
Output
beep
beep
beep
beep