| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.ratis.util; |
| |
| import org.apache.ratis.util.function.CheckedRunnable; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.io.Closeable; |
| import java.util.Collection; |
| import java.util.Optional; |
| import java.util.concurrent.ScheduledFuture; |
| import java.util.concurrent.ScheduledThreadPoolExecutor; |
| import java.util.concurrent.ThreadFactory; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.atomic.AtomicReference; |
| import java.util.function.Consumer; |
| import java.util.function.Supplier; |
| |
| public final class TimeoutScheduler implements Closeable { |
| public static final Logger LOG = LoggerFactory.getLogger(TimeoutScheduler.class); |
| |
| static final TimeDuration DEFAULT_GRACE_PERIOD = TimeDuration.valueOf(1, TimeUnit.MINUTES); |
| |
| private static final Supplier<TimeoutScheduler> INSTANCE = JavaUtils.memoize(TimeoutScheduler::new); |
| |
| public static TimeoutScheduler getInstance() { |
| return INSTANCE.get(); |
| } |
| |
| static TimeoutScheduler newInstance() { |
| return new TimeoutScheduler(); |
| } |
| |
| static class ShutdownTask { |
| private final int sid; |
| private final ScheduledFuture<?> future; |
| |
| ShutdownTask(int sid, ScheduledFuture<?> future) { |
| this.sid = sid; |
| this.future = future; |
| } |
| |
| int getSid() { |
| return sid; |
| } |
| |
| void cancel() { |
| future.cancel(false); |
| } |
| } |
| |
| private static class Scheduler { |
| private final AtomicReference<ScheduledThreadPoolExecutor> executor = new AtomicReference<>(); |
| |
| boolean hasExecutor() { |
| return executor.get() != null; |
| } |
| |
| int getQueueSize() { |
| return Optional.ofNullable(executor.get()) |
| .map(ScheduledThreadPoolExecutor::getQueue) |
| .map(Collection::size).orElse(0); |
| } |
| |
| ScheduledFuture<?> schedule(Runnable task, Supplier<String> name, TimeDuration time) { |
| return executor.updateAndGet(e -> Optional.ofNullable(e).orElseGet(Scheduler::newExecutor)) |
| .schedule(LogUtils.newRunnable(LOG, task, name), time.getDuration(), time.getUnit()); |
| } |
| |
| private static ScheduledThreadPoolExecutor newExecutor() { |
| LOG.debug("new ScheduledThreadPoolExecutor"); |
| final ScheduledThreadPoolExecutor e = new ScheduledThreadPoolExecutor(1, (ThreadFactory) Daemon::new); |
| e.setRemoveOnCancelPolicy(true); |
| return e; |
| } |
| |
| void shutdown() { |
| Optional.ofNullable(executor.getAndSet(null)).ifPresent(ScheduledThreadPoolExecutor::shutdown); |
| } |
| } |
| |
| /** When there is no tasks, the time period to wait before shutting down the scheduler. */ |
| private final AtomicReference<TimeDuration> gracePeriod = new AtomicReference<>(DEFAULT_GRACE_PERIOD); |
| |
| /** The number of scheduled tasks. */ |
| private int numTasks = 0; |
| /** The scheduleID for each task */ |
| private int scheduleID = 0; |
| |
| private ShutdownTask shutdownTask = null; |
| |
| private final Scheduler scheduler = new Scheduler(); |
| |
| private TimeoutScheduler() { |
| } |
| |
| int getQueueSize() { |
| return scheduler.getQueueSize(); |
| } |
| |
| TimeDuration getGracePeriod() { |
| return gracePeriod.get(); |
| } |
| |
| void setGracePeriod(TimeDuration gracePeriod) { |
| this.gracePeriod.set(gracePeriod); |
| } |
| |
| boolean hasScheduler() { |
| return scheduler.hasExecutor(); |
| } |
| |
| /** |
| * Schedule a timeout task. |
| * |
| * @param timeout the timeout value. |
| * @param task the task to run when timeout. |
| * @param errorHandler to handle the error, if there is any. |
| */ |
| public <THROWABLE extends Throwable> void onTimeout( |
| TimeDuration timeout, CheckedRunnable<THROWABLE> task, Consumer<THROWABLE> errorHandler) { |
| onTimeout(timeout, sid -> { |
| LOG.debug("run a task: sid {}", sid); |
| try { |
| task.run(); |
| } catch(Throwable t) { |
| errorHandler.accept(JavaUtils.cast(t)); |
| } finally { |
| onTaskCompleted(); |
| } |
| }); |
| } |
| |
| private synchronized void onTimeout(TimeDuration timeout, Consumer<Integer> toSchedule) { |
| numTasks++; |
| final int sid = scheduleID++; |
| |
| LOG.debug("schedule a task: timeout {}, sid {}", timeout, sid); |
| scheduler.schedule(() -> toSchedule.accept(sid), () -> "task #" + sid, timeout); |
| } |
| |
| private synchronized void onTaskCompleted() { |
| if (--numTasks > 0) { |
| return; |
| } |
| final int sid = scheduleID; |
| if (shutdownTask != null) { |
| if (shutdownTask.getSid() == sid) { |
| // the shutdown task is still valid |
| return; |
| } |
| // the shutdown task is invalid |
| shutdownTask.cancel(); |
| } |
| |
| final TimeDuration grace = getGracePeriod(); |
| LOG.debug("Schedule a shutdown task: grace {}, sid {}", grace, sid); |
| final ScheduledFuture<?> future = scheduler.schedule(() -> tryShutdownScheduler(sid), |
| () -> "shutdown task #" + sid, grace); |
| shutdownTask = new ShutdownTask(sid, future); |
| } |
| |
| private synchronized void tryShutdownScheduler(int sid) { |
| if (sid == scheduleID) { |
| // No new tasks submitted, shutdown the scheduler. |
| LOG.debug("shutdown scheduler: sid {}", sid); |
| scheduler.shutdown(); |
| } else { |
| LOG.debug("shutdown cancelled: scheduleID has changed from {} to {}", sid, scheduleID); |
| } |
| } |
| |
| /** When timeout, run the task. Log the error, if there is any. */ |
| public void onTimeout(TimeDuration timeout, CheckedRunnable<?> task, Logger log, Supplier<String> errorMessage) { |
| onTimeout(timeout, task, t -> log.error(errorMessage.get(), t)); |
| } |
| |
| @Override |
| public synchronized void close() { |
| tryShutdownScheduler(scheduleID); |
| } |
| } |