sh.props.BackgroundExecutorFactory Maven / Gradle / Ivy
/*
* MIT License
*
* Copyright (c) 2021 - 2021 Mihai Bojin
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
package sh.props;
import static java.lang.String.format;
import java.time.Duration;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.logging.Logger;
public class BackgroundExecutorFactory {
public static final Duration DEFAULT_GRACE_PERIOD = Duration.ofSeconds(5);
private static final Logger log = Logger.getLogger(BackgroundExecutorFactory.class.getName());
/**
* Creates {@link ScheduledExecutorService} based on daemon {@link Thread}s, setting a default
* parallelism matching the system's available threads, as returned by {@link
* Runtime#availableProcessors()}.
*
* Any such executors will attempt graceful shutdown when instructed and will wait for any
* current requests to complete, up to the default {@link #DEFAULT_GRACE_PERIOD}.
*
* @return an initialized scheduled executor
*/
public static ScheduledExecutorService create() {
return create(Runtime.getRuntime().availableProcessors(), DEFAULT_GRACE_PERIOD);
}
/**
* Creates {@link ScheduledExecutorService} based on daemon {@link Thread}s.
*
*
Any such executors will attempt graceful shutdown when instructed and will wait for any
* current requests to complete, up to the default {@link #DEFAULT_GRACE_PERIOD}.
*
* @param threads the number of threads in the pool
* @return an initialized scheduled executor
*/
public static ScheduledExecutorService create(int threads) {
return create(threads, DEFAULT_GRACE_PERIOD);
}
/**
* Creates {@link ScheduledExecutorService} based on daemon {@link Thread}s.
*
*
Any such executors will attempt graceful shutdown when instructed and will wait for any
* current requests to complete, up to the specified grace period (millisecond granularity).
*
* @param threads the number of threads in the pool
* @param shutdownGracePeriod the maximum grace period before forcefully shutting down the
* executor
* @return an initialized scheduled executor
*/
public static ScheduledExecutorService create(int threads, Duration shutdownGracePeriod) {
var executor = Executors.newScheduledThreadPool(threads, new DaemonThreadFactory());
Runtime.getRuntime().addShutdownHook(new Thread(() -> shutdown(executor, shutdownGracePeriod)));
log.info(
() ->
format(
"Initialized %s with %d threads and a grace period of %d ms",
executor, threads, shutdownGracePeriod.toMillis()));
return executor;
}
/**
* Gracefully terminate the specified {@link ScheduledExecutorService}, waiting for the specified
* grace period (millisecond granularity).
*
* @param executor the executor to shutdown
* @param gracePeriod the maximum grace period before forcing a shutdown
*/
public static void shutdown(ExecutorService executor, Duration gracePeriod) {
boolean ok = true;
log.info(() -> format("Attempting to shut down %s", executor));
long t0 = System.currentTimeMillis();
executor.shutdown();
try {
// wait for running threads to complete
ok = executor.awaitTermination(gracePeriod.toMillis(), TimeUnit.MILLISECONDS);
log.info(
() ->
format(
"%s shut down after %d milliseconds", executor, System.currentTimeMillis() - t0));
} catch (InterruptedException e) {
log.warning(() -> format("Interrupted while waiting for shutdown %s", executor));
ok = false;
Thread.currentThread().interrupt();
} finally {
// if the executor could not be shutdown, attempt to forcefully shut it down
if (!ok) {
log.info(() -> format("Attempting a forceful shutdown of %s", executor));
executor.shutdownNow();
}
}
}
}