org.apache.flink.runtime.taskexecutor.slot.TimerService Maven / Gradle / Ivy
/*
* 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.flink.runtime.taskexecutor.slot;
import org.apache.flink.util.Preconditions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
/**
* Service to register timeouts for a given key. The timeouts are identified by a ticket so that
* newly registered timeouts for the same key can be distinguished from older timeouts.
*
* @param Type of the key
*/
public class TimerService {
private static final Logger LOG = LoggerFactory.getLogger(TimerService.class);
/** Executor service for the scheduled timeouts. */
private final ScheduledExecutorService scheduledExecutorService;
/** Timeout for the shutdown of the service. */
private final long shutdownTimeout;
/** Map of currently active timeouts. */
private final Map> timeouts;
/** Listener which is notified about occurring timeouts. */
private TimeoutListener timeoutListener;
public TimerService(
final ScheduledExecutorService scheduledExecutorService,
final long shutdownTimeout) {
this.scheduledExecutorService = Preconditions.checkNotNull(scheduledExecutorService);
Preconditions.checkArgument(shutdownTimeout >= 0L, "The shut down timeout must be larger than or equal than 0.");
this.shutdownTimeout = shutdownTimeout;
this.timeouts = new HashMap<>(16);
this.timeoutListener = null;
}
public void start(TimeoutListener initialTimeoutListener) {
// sanity check; We only allow to assign a timeout listener once
Preconditions.checkState(!scheduledExecutorService.isShutdown());
Preconditions.checkState(timeoutListener == null);
this.timeoutListener = Preconditions.checkNotNull(initialTimeoutListener);
}
public void stop() {
unregisterAllTimeouts();
timeoutListener = null;
scheduledExecutorService.shutdown();
try {
if (!scheduledExecutorService.awaitTermination(shutdownTimeout, TimeUnit.MILLISECONDS)) {
LOG.debug("The scheduled executor service did not properly terminate. Shutting " +
"it down now.");
scheduledExecutorService.shutdownNow();
}
} catch (InterruptedException e) {
LOG.debug("Could not properly await the termination of the scheduled executor service.", e);
scheduledExecutorService.shutdownNow();
}
}
/**
* Register a timeout for the given key which shall occur in the given delay.
*
* @param key for which to register the timeout
* @param delay until the timeout
* @param unit of the timeout delay
*/
public void registerTimeout(final K key, final long delay, final TimeUnit unit) {
Preconditions.checkState(timeoutListener != null, "The " + getClass().getSimpleName() +
" has not been started.");
if (timeouts.containsKey(key)) {
unregisterTimeout(key);
}
timeouts.put(key, new Timeout<>(timeoutListener, key, delay, unit, scheduledExecutorService));
}
/**
* Unregister the timeout for the given key.
*
* @param key for which to unregister the timeout
*/
public void unregisterTimeout(K key) {
Timeout timeout = timeouts.remove(key);
if (timeout != null) {
timeout.cancel();
}
}
/**
* Unregister all timeouts.
*/
protected void unregisterAllTimeouts() {
for (Timeout timeout : timeouts.values()) {
timeout.cancel();
}
timeouts.clear();
}
/**
* Check whether the timeout for the given key and ticket is still valid (not yet unregistered
* and not yet overwritten).
*
* @param key for which to check the timeout
* @param ticket of the timeout
* @return True if the timeout ticket is still valid; otherwise false
*/
public boolean isValid(K key, UUID ticket) {
if (timeouts.containsKey(key)) {
Timeout timeout = timeouts.get(key);
return timeout.getTicket().equals(ticket);
} else {
return false;
}
}
// ---------------------------------------------------------------------
// Static utility classes
// ---------------------------------------------------------------------
private static final class Timeout implements Runnable {
private final TimeoutListener timeoutListener;
private final K key;
private final ScheduledFuture scheduledTimeout;
private final UUID ticket;
Timeout(
final TimeoutListener timeoutListener,
final K key,
final long delay,
final TimeUnit unit,
final ScheduledExecutorService scheduledExecutorService) {
Preconditions.checkNotNull(scheduledExecutorService);
this.timeoutListener = Preconditions.checkNotNull(timeoutListener);
this.key = Preconditions.checkNotNull(key);
this.scheduledTimeout = scheduledExecutorService.schedule(this, delay, unit);
this.ticket = UUID.randomUUID();
}
UUID getTicket() {
return ticket;
}
void cancel() {
scheduledTimeout.cancel(true);
}
@Override
public void run() {
timeoutListener.notifyTimeout(key, ticket);
}
}
}