java.util.concurrent.ScheduledExecutorService#schedule ( )源码实例Demo

public JdbcQuery ( final StorageDao jdbcStorageDao, final Filter filter, final ScheduledExecutorService executor, final List<JdbcQuery> openQueries ) throws SQLException, NotSupportedException
{
    openQueries.add ( this );
    this.openQueries = new WeakReference<List<JdbcQuery>> ( openQueries );
    this.jdbcStorageDao = jdbcStorageDao;
    this.resultSet = jdbcStorageDao.queryEvents ( filter );
    this.statement = this.resultSet.getStatement ();
    this.hasMore = this.resultSet.next ();
    this.future = executor.schedule ( new Callable<Boolean> () {
        @Override
        public Boolean call ()
        {
            logger.warn ( "Query '{}' was open for over an hour, or service is being shut down, and will now be closed automatically" );
            dispose ();
            return true;
        }
    }, 1, TimeUnit.HOURS );
}
 

@Test
public void scheduleCallableCancelTest() {
  ScheduledExecutorService scheduler = makeScheduler(1);
  try {
    TestCallable tcDelay = new TestCallable(0);
    ScheduledFuture<Object> delayF = scheduler.schedule(tcDelay, 20, TimeUnit.MILLISECONDS);
    long delay = delayF.getDelay(TimeUnit.MILLISECONDS);
    boolean canceled = delayF.cancel(true);
    
    assertTrue(delay <= 20);
    if (canceled) {
      assertTrue(delayF.isCancelled());
    }
  } finally {
    scheduler.shutdownNow();
  }
}
 

@Test(timeout = 2000)
public void emptyDefaultCompletable() throws Exception {
    ScheduledExecutorService exec = Executors.newScheduledThreadPool(1);
    try {
        DirectProcessor<Integer> sp = new DirectProcessor<>();
        
        Future<Integer> f = sp.toCompletableFuture(1);
        
        exec.schedule(() -> { sp.onComplete(); }, 500, TimeUnit.MILLISECONDS);
        
        Assert.assertEquals((Integer)1, f.get());
        
    } finally {
        exec.shutdown();
    }
}
 

public static void main(String[] args) {
	logClassPathContent(); // We might not have a solution for this method when migrating to Java 9 - whats the best call?

	Monitor monitor = createMonitor();
	MonitorServer server = MonitorServer
			.create(monitor::currentStatistics)
			.start();

	ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
	scheduler.scheduleAtFixedRate(monitor::updateStatistics, 1, 1, TimeUnit.SECONDS);
	scheduler.schedule(() -> {
				scheduler.shutdown();
				server.shutdown();
			},
			10,
			TimeUnit.SECONDS);
}
 

/**
 * @param task any exception throwing would cancel the task. user should swallow exceptions by self.
 * @param executor all task would be stopped after executor has been marked shutting down.
 * @return a future that can cancel the task.
 */
public static Future<?> scheduleWithDynamicDelay(@Nonnull ScheduledExecutorService executor,
        @Nullable Duration initDelay, @Nonnull Scheduled task) {
    checkNotNull(executor);
    checkNotNull(task);
    AtomicBoolean canceled = new AtomicBoolean(false);
    AbstractFuture<?> future = new AbstractFuture<Object>() {

        @Override
        public boolean cancel(boolean mayInterruptIfRunning) {
            canceled.set(true);
            return super.cancel(mayInterruptIfRunning);
        }
    };
    executor.schedule(new ScheduledTaskImpl(executor, task, canceled),
            initDelay == null ? 0 : initDelay.toMillis(), MILLISECONDS);
    return future;
}
 

@Test(timeout = 2000)
public void emptyCompletable() throws Exception {
    ScheduledExecutorService exec = Executors.newScheduledThreadPool(1);
    try {
        DirectProcessor<Integer> sp = new DirectProcessor<>();
        
        Future<Integer> f = sp.toCompletableFuture();
        
        exec.schedule(() -> { sp.onComplete(); }, 500, TimeUnit.MILLISECONDS);

        try {
            Integer v = f.get();
            Assert.fail("Failed to throw ExecutionException and returned a value: " + v);
        } catch (ExecutionException ex) {
            if (!(ex.getCause() instanceof NoSuchElementException)) {
                throw ex;
            }
        }
        
    } finally {
        exec.shutdown();
    }
}
 

/**
 * Execute a runnable after the given delay.
 * @param runnable the task to execute
 * @param delay    the time from now to delay execution, in milliseconds
 * @return Future associated to the running task
 * @throws IllegalArgumentException if <code>delay</code> is strictly positive and the current
 *                                  executor does not support scheduling (if
 *                                  {@link #setExecutor(Executor)} has been called with such an
 *                                  executor)
 */
private static Future<?> directExecute(Runnable runnable, int delay) {
    Future<?> future = null;
    if (delay > 0) {
        /* no serial, but a delay: schedule the task */
        if (!(executor instanceof ScheduledExecutorService)) {
            throw new IllegalArgumentException("The executor set does not support scheduling");
        }
        ScheduledExecutorService scheduledExecutorService = (ScheduledExecutorService) executor;
        future = scheduledExecutorService.schedule(runnable, delay, TimeUnit.MILLISECONDS);
    } else {
        if (executor instanceof ExecutorService) {
            ExecutorService executorService = (ExecutorService) executor;
            future = executorService.submit(runnable);
        } else {
            /* non-cancellable task */
            executor.execute(runnable);
        }
    }
    return future;
}
 

@Override
public final CompletableFuture<Endpoint> select(ClientRequestContext ctx,
                                                ScheduledExecutorService executor,
                                                long timeoutMillis) {
    Endpoint endpoint = selectNow(ctx);
    if (endpoint != null) {
        return UnmodifiableFuture.completedFuture(endpoint);
    }

    final ListeningFuture listeningFuture = new ListeningFuture(ctx, executor);
    endpointGroup.addListener(listeningFuture);

    // Try to select again because the EndpointGroup might have been updated
    // between selectNow() and addListener() above.
    endpoint = selectNow(ctx);
    if (endpoint != null) {
        endpointGroup.removeListener(listeningFuture);
        return UnmodifiableFuture.completedFuture(endpoint);
    }

    // Schedule the timeout task.
    final ScheduledFuture<?> timeoutFuture =
            executor.schedule(() -> listeningFuture.complete(null),
                              timeoutMillis, TimeUnit.MILLISECONDS);
    listeningFuture.timeoutFuture = timeoutFuture;

    // Cancel the timeout task if listeningFuture is done already.
    // This guards against the following race condition:
    // 1) (Current thread) Timeout task is scheduled.
    // 2) ( Other thread ) listeningFuture is completed, but the timeout task is not cancelled
    // 3) (Current thread) timeoutFuture is assigned to listeningFuture.timeoutFuture, but it's too late.
    if (listeningFuture.isDone()) {
        timeoutFuture.cancel(false);
    }

    return listeningFuture;
}
 

public static void main(String[] args) {
    ScheduledExecutorService timer = Executors.newScheduledThreadPool(2);
    long delay = computeDelay();
    timer.schedule(new ThrowExceptionTask(timer), delay, TimeUnit.MILLISECONDS);
    timer.schedule(new NotThrowExceptionTask(timer), delay, TimeUnit.MILLISECONDS);
    System.out.println("主线程的功能执行完毕");
}
 

@Test
public void testNewScheduledThreadPoolWithThreadFactory() throws Exception {
    final ScheduledExecutorService executorService = InstrumentedExecutors.newScheduledThreadPool(2, defaultThreadFactory, registry);
    executorService.schedule(new NoopRunnable(), 0, TimeUnit.SECONDS);

    final Field delegateField = InstrumentedScheduledExecutorService.class.getDeclaredField("delegate");
    delegateField.setAccessible(true);
    final ScheduledThreadPoolExecutor delegate = (ScheduledThreadPoolExecutor) delegateField.get(executorService);
    assertThat(delegate.getCorePoolSize()).isEqualTo(2);
    assertThat(delegate.getThreadFactory()).isSameAs(defaultThreadFactory);
    executorService.shutdown();
}
 

public static void main(String[] args) {

        HttpHandler exceptionHandler =
                CustomHandlers.exception(CIRCUIT_BREAKER_HANDLER)
                              .addExceptionHandler(Throwable.class, FailsafeWebserver::serverError);

        SimpleServer server = SimpleServer.simpleServer(exceptionHandler);
        server.start();


        // Warm-up the circuit breaker it needs to hit at least max executions
        // Before it will reject anything. This will make that easier.
        for (int i = 0; i < 10; i++) {
            request("warmup", false, false);
        }
        ScheduledExecutorService schedExec = Executors.newScheduledThreadPool(1);

        // A simple request that should always succeed
        schedExec.scheduleAtFixedRate(() -> request("ping", false, false), 0, 500, TimeUnit.MILLISECONDS);

        // Send a batch of 15 bad requests to trigger the circuit breaker
        Runnable errors = () -> {
            log.info("Start: Executing bad requests!");
            for (int i = 0; i < 15; i++) {
                request("bad request", true, false);
            }
            log.info("End: Executing bad requests!");
        };
        schedExec.schedule(errors, 1, TimeUnit.SECONDS);

        // Send a batch of 15 requests that throw exceptions
        Runnable exceptions = () -> {
            log.info("Start: Executing requests that throw exceptions!");
            for (int i = 0; i < 15; i++) {
                request("exception request", false, true);
            }
            log.info("End: Executing requests that throw exceptions!");
        };
        schedExec.schedule(exceptions, 5, TimeUnit.SECONDS);
    }
 

@Override
public ScheduledFuture<?> schedule(Runnable task, Date startTime) {
	ScheduledExecutorService executor = getScheduledExecutor();
	long initialDelay = startTime.getTime() - System.currentTimeMillis();
	try {
		return executor.schedule(errorHandlingTask(task, false), initialDelay, TimeUnit.MILLISECONDS);
	}
	catch (RejectedExecutionException ex) {
		throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
	}
}
 

public static boolean isMaster(final HazelcastInstance hazelcastInstance, ScheduledExecutorService executor,
                               int delaySeconds) {
    if (hazelcastInstance == null || !isOldestMember(hazelcastInstance)) {
        return false;
    }
    try {
        Callable<Boolean> callable = () -> isOldestMember(hazelcastInstance);
        ScheduledFuture<Boolean> future = executor.schedule(callable, delaySeconds, TimeUnit.SECONDS);
        return future.get(TIMEOUT_SECONDS, TimeUnit.SECONDS);
    } catch (InterruptedException | ExecutionException | TimeoutException e) {
        throw new IllegalStateException(e);
    }
}
 

/**
 * wait 2 seconds before closing the socket connection, this should allow time of the
 * termination event to be sent.
 */
private void closeSoon() {
    if (isClosing.compareAndSet(false, true)) {
        @NotNull final ScheduledExecutorService closer = newSingleThreadScheduledExecutor(new NamedThreadFactory("closer", true));
        closer.schedule(() -> {
            close();
            closer.shutdown();
        }, 2, SECONDS);
    }
}
 

private void start(DataStoreService dataStoreService) {

        ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(4);
        ThreadPoolExecutor checkDataNodeListChangeExecutor = new ThreadPoolExecutor(1, 2,
                0, TimeUnit.SECONDS, new SynchronousQueue<>());

        scheduler.schedule(new TimedSupervisorTask("CheckDataNodeListChange", scheduler,
                checkDataNodeListChangeExecutor, 500, TimeUnit.MILLISECONDS, 3,
                dataStoreService::pushNodeListChange), 1, TimeUnit.SECONDS);
    }
 

/**
 * Schedules a call to {@link #queue(java.util.function.Consumer, java.util.function.Consumer)}
 * to be executed after the specified {@code delay}.
 * <br>This is an <b>asynchronous</b> operation that will return a
 * {@link java.util.concurrent.ScheduledFuture ScheduledFuture} representing the task.
 *
 * <p>The specified {@link java.util.concurrent.ScheduledExecutorService ScheduledExecutorService} is used for this operation.
 *
 * @param  delay
 *         The delay after which this computation should be executed, negative to execute immediately
 * @param  unit
 *         The {@link java.util.concurrent.TimeUnit TimeUnit} to convert the specified {@code delay}
 * @param  success
 *         The success {@link java.util.function.Consumer Consumer} that should be called
 *         once the {@link #queue(java.util.function.Consumer, java.util.function.Consumer)} operation completes successfully.
 * @param  failure
 *         The failure {@link java.util.function.Consumer Consumer} that should be called
 *         in case of an error of the {@link #queue(java.util.function.Consumer, java.util.function.Consumer)} operation.
 * @param  executor
 *         The Non-null {@link java.util.concurrent.ScheduledExecutorService ScheduledExecutorService} that should be used
 *         to schedule this operation
 *
 * @throws java.lang.IllegalArgumentException
 *         If the provided TimeUnit or ScheduledExecutorService is {@code null}
 *
 * @return {@link java.util.concurrent.ScheduledFuture ScheduledFuture}
 *         representing the delayed operation
 *
 * @see    net.dv8tion.jda.api.exceptions.ErrorHandler
 */
@Nonnull
default ScheduledFuture<?> queueAfter(long delay, @Nonnull TimeUnit unit, @Nullable Consumer<? super T> success, @Nullable Consumer<? super Throwable> failure, @Nullable ScheduledExecutorService executor)
{
    Checks.notNull(unit, "TimeUnit");
    if (executor == null)
        executor = getJDA().getRateLimitPool();

    final Consumer<? super Throwable> onFailure;
    if (isPassContext())
        onFailure = ContextException.here(failure == null ? getDefaultFailure() : failure);
    else
        onFailure = failure;

    Runnable task = new ContextRunnable<Void>(() -> queue(success, onFailure));
    return executor.schedule(task, delay, unit);
}
 

public WithinPromise(final InterruptHandler handler, final Duration timeout,
    final ScheduledExecutorService scheduler, final Throwable exception) {
  this.handler = handler;
  this.task = scheduler.schedule(this, timeout.toMillis(), TimeUnit.MILLISECONDS);
  this.exception = exception;
}
 

private void delaySecondClick()
{
	final ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor();
	service.schedule(this::simLeftClick, randomDelay(90, 100), TimeUnit.MILLISECONDS);
	service.shutdown();
}
 

/**
 * start screen capture after "delay" milliseconds, so the previous activity's
 * state recover to normal state, such as button click, list item click,wait
 * them to normal state so we can make a good screen capture
 *
 * @param context
 * @param intent
 * @param delay   time in milliseconds
 */
public static void startPreviewActivity(final Context context, final Intent intent, long delay) {
    final Handler mainThread = new Handler(Looper.getMainLooper());
    final Runnable postAction = new Runnable() {
        @Override
        public void run() {
            context.startActivity(intent);
        }
    };

    /** process screen capture on background thread */
    Runnable action = new Runnable() {
        @Override
        public void run() {
            /**
             * activity's root layout id, you can change the android.R.id.content to your root
             * layout id
             */
            final View contentView = ((Activity) context).findViewById(android.R.id.content);

            ByteArrayOutputStream baos = null;
            Bitmap bitmap = null;

            try {
                bitmap = Bitmap.createBitmap(contentView.getWidth(),
                        contentView.getHeight(), Bitmap.Config.ARGB_8888);
                contentView.draw(new Canvas(bitmap));

                baos = new ByteArrayOutputStream();
                bitmap.compress(Bitmap.CompressFormat.JPEG, 70, baos);
                intent.putExtra(KEY_PREVIEW_IMAGE, baos.toByteArray());
            } finally {
                try {
                    /** no need to close, actually do nothing */
                    if (null != baos) baos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (null != bitmap && !bitmap.isRecycled()) {
                    bitmap.recycle();
                    bitmap = null;
                }
            }
            mainThread.post(postAction);
        }
    };

    if (delay > 0) {
        ScheduledExecutorService worker = Executors.newSingleThreadScheduledExecutor();
        worker.schedule(action, delay, TimeUnit.MILLISECONDS);
    } else {
        action.run();
    }
}
 

/**
 * Returns a future that is completed with the {@code result} on the {@code executor}.
 */
public static CompletableFuture<Object> futureResult(ScheduledExecutorService executor, Object result) {
  CompletableFuture<Object> future = new CompletableFuture<>();
  executor.schedule(() -> future.complete(result), 0, TimeUnit.MILLISECONDS);
  return future;
}