ScheduledExecutorServiceソース分析

詳細

public interface ScheduledExecutorService extends ExecutorService {

	//                     
	public ScheduledFuture> schedule(Runnable command,
				       long delay, TimeUnit unit);

	//   ，   callable  
	public  ScheduledFuture schedule(Callable callable,
					   long delay, TimeUnit unit);

	//                     
	//             ，             ，        。
	public ScheduledFuture> scheduleAtFixedRate(Runnable command,
						  long initialDelay,
						  long period,
						  TimeUnit unit);

	//                     。
	//       ：   delay           ，             。
	public ScheduledFuture> scheduleWithFixedDelay(Runnable command,
						     long initialDelay,
						     long delay,
						     TimeUnit unit);

}

テスト:

public class ScheduledExecutorServiceTest {

	private static final int POOL_SIZE = 4;
	
	private static ScheduledExecutorService ses = null;
	
	@org.junit.Before
	public void setUp() {
		ses = Executors.newScheduledThreadPool(POOL_SIZE);
	}
	
	@After
	public void tearDown() {
		ses.shutdown();
	}
	
    @Test
    public void scheduled() throws ExecutionException, InterruptedException {
        MyCall task = new MyCall();
        System.out.println(System.currentTimeMillis() + " : scheduled...");
        //   100+1000    
        ScheduledFuture future = ses.schedule(task, 100, TimeUnit.MILLISECONDS);
        String result = future.get();
        System.out.println(System.currentTimeMillis() + " result: " + result);
    }

    @Test
    public void scheduledAtFixedRateTest() throws InterruptedException {
        MyCmd myCmd = new MyCmd();
        System.out.println(System.currentTimeMillis() + " : scheduledAtFixedRate...");
        //     100  ，    max(2000,3000)    
        ses.scheduleAtFixedRate(myCmd, 100, 2000, TimeUnit.MILLISECONDS);
        TimeUnit.MILLISECONDS.sleep(60000);
    }

    @Test
    public void scheduledAfFixedDelayTest() throws InterruptedException {
        MyCmd myCmd = new MyCmd();
        System.out.println(System.currentTimeMillis() + " : scheduledAfFixedDelay...");
        //     100  ，    5000    
        ses.scheduleWithFixedDelay(myCmd, 100, 2000, TimeUnit.MILLISECONDS);
        TimeUnit.MILLISECONDS.sleep(60000);
    }

    static class MyCall implements Callable {

        @Override
        public String call() throws Exception {
            TimeUnit.MILLISECONDS.sleep(1000);
            return "MyTask is done";
        }
    }

    static class MyCmd implements Runnable {
        @Override
        public void run() {
            try {
                TimeUnit.MILLISECONDS.sleep(3000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(System.currentTimeMillis() + " : MyCmd is done!");
        }
    }
}

scheduled出力(遅延100+1000ミリ秒印刷)
1505538732156 : scheduled...
1505538733257 result : MyTask is done
scheduledAtFixedRateTest出力(3000ミリ秒間隔=max(2000,3000):
1505538684893 :scheduledAtFixedRate...
1505538687996 : MyCmd is done!
1505538690997 : MyCmd is done!
scheduledAtFixedDelayTest出力(5000ミリ秒間隔=2000+3000):
1505536678015 :scheduledAfFixedDelay...
1505536681117 : MyCmd is done!
1505536686118 : MyCmd is done!