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📜  ScheduledThreadPoolExecutor类

📅  最后修改于: 2020-11-15 03:59:11             🧑  作者: Mango

java.util.concurrent.ScheduledThreadPoolExecutor是ThreadPoolExecutor的子类，还可以安排命令在给定的延迟后运行或定期执行。

ScheduledThreadPoolExecutor方法

Sr.No. Method & Description
1

protected RunnableScheduledFuture decorateTask(Callable callable, RunnableScheduledFuture task)

Modifies or replaces the task used to execute a callable.
2

protected RunnableScheduledFuture decorateTask(Runnable runnable, RunnableScheduledFuture task)

Modifies or replaces the task used to execute a runnable.
3

void execute(Runnable command)

Executes command with zero required delay.
4

boolean getContinueExistingPeriodicTasksAfterShutdownPolicy()

Gets the policy on whether to continue executing existing periodic tasks even when this executor has been shutdown.
5

boolean getExecuteExistingDelayedTasksAfterShutdownPolicy()

Gets the policy on whether to execute existing delayed tasks even when this executor has been shutdown.
6

BlockingQueue getQueue()

Returns the task queue used by this executor.
7

boolean getRemoveOnCancelPolicy()

Gets the policy on whether cancelled tasks should be immediately removed from the work queue at time of cancellation.
8

ScheduledFuture schedule(Callable callable, long delay, TimeUnit unit)

Creates and executes a ScheduledFuture that becomes enabled after the given delay.
9

ScheduledFuture schedule(Runnable command, long delay, TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay.
10

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.
11

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.
12

void setContinueExistingPeriodicTasksAfterShutdownPolicy (boolean value)

Sets the policy on whether to continue executing existing periodic tasks even when this executor has been shutdown.
13

void setExecuteExistingDelayedTasksAfterShutdownPolicy (boolean value)

Sets the policy on whether to execute existing delayed tasks even when this executor has been shutdown.
14

void setRemoveOnCancelPolicy(boolean value)

Sets the policy on whether cancelled tasks should be immediately removed from the work queue at time of cancellation.
15

void shutdown()

Initiates an orderly shutdown in which previously submitted tasks are executed, but no new tasks will be accepted.
16

List shutdownNow()

Attempts to stop all actively executing tasks, halts the processing of waiting tasks, and returns a list of the tasks that were awaiting execution.
17

Futuresubmit(Callable task)

Submits a value-returning task for execution and returns a Future representing the pending results of the task.
18

Future submit(Runnable task)

Submits a Runnable task for execution and returns a Future representing that task.
19

Futuresubmit(Runnable task, T result)

Submits a Runnable task for execution and returns a Future representing that task.

例

下面的TestThread程序显示了在基于线程的环境中ScheduledThreadPoolExecutor接口的用法。

现场演示
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

public class TestThread {

   public static void main(final String[] arguments) throws InterruptedException {
      final ScheduledThreadPoolExecutor scheduler = 
         (ScheduledThreadPoolExecutor)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");      
      }
   }
}

这将产生以下结果。

输出

beep
beep
beep
beep