org.apache.druid.java.util.common.concurrent.ScheduledExecutors.java Source code

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Here is the source code for org.apache.druid.java.util.common.concurrent.ScheduledExecutors.java

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/*
 * 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.druid.java.util.common.concurrent;

import org.apache.druid.java.util.common.lifecycle.Lifecycle;
import org.apache.druid.java.util.common.logger.Logger;
import org.joda.time.Duration;

import java.util.concurrent.Callable;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class ScheduledExecutors {
    private static final Logger log = new Logger(ScheduledExecutors.class);

    /**
     * Run runnable repeatedly with the given delay between calls, after the given
     * initial delay. Exceptions are caught and logged as errors.
     */
    public static void scheduleWithFixedDelay(final ScheduledExecutorService exec, final Duration initialDelay,
            final Duration delay, final Runnable runnable) {
        scheduleWithFixedDelay(exec, initialDelay, delay, new Callable<Signal>() {
            @Override
            public Signal call() {
                runnable.run(); // (Exceptions are handled for us)
                return Signal.REPEAT;
            }
        });
    }

    /**
     * Run callable repeatedly with the given delay between calls, after the given
     * initial delay, until it returns Signal.STOP. Exceptions are caught and
     * logged as errors.
     */
    public static void scheduleWithFixedDelay(ScheduledExecutorService exec, Duration delay,
            Callable<Signal> callable) {
        scheduleWithFixedDelay(exec, delay, delay, callable);
    }

    /**
     * Run callable repeatedly with the given delay between calls, until it
     * returns Signal.STOP. Exceptions are caught and logged as errors.
     */
    public static void scheduleWithFixedDelay(final ScheduledExecutorService exec, final Duration initialDelay,
            final Duration delay, final Callable<Signal> callable) {
        log.debug("Scheduling repeatedly: %s with delay %s", callable, delay);
        exec.schedule(new Runnable() {
            @Override
            public void run() {
                try {
                    log.trace("Running %s (delay %s)", callable, delay);
                    if (callable.call() == Signal.REPEAT) {
                        log.trace("Rescheduling %s (delay %s)", callable, delay);
                        exec.schedule(this, delay.getMillis(), TimeUnit.MILLISECONDS);
                    } else {
                        log.debug("Stopped rescheduling %s (delay %s)", callable, delay);
                    }
                } catch (Throwable e) {
                    log.error(e, "Uncaught exception.");
                }
            }
        }, initialDelay.getMillis(), TimeUnit.MILLISECONDS);
    }

    /**
     * Run runnable once every period, after the given initial delay. Exceptions
     * are caught and logged as errors.
     */
    public static void scheduleAtFixedRate(final ScheduledExecutorService exec, final Duration initialDelay,
            final Duration period, final Runnable runnable) {
        scheduleAtFixedRate(exec, initialDelay, period, new Callable<Signal>() {
            @Override
            public Signal call() {
                runnable.run();
                return Signal.REPEAT;
            }
        });
    }

    public static void scheduleAtFixedRate(ScheduledExecutorService exec, Duration rate,
            Callable<Signal> callable) {
        scheduleAtFixedRate(exec, rate, rate, callable);
    }

    public static void scheduleAtFixedRate(final ScheduledExecutorService exec, final Duration initialDelay,
            final Duration rate, final Callable<Signal> callable) {
        log.debug("Scheduling periodically: %s with period %s", callable, rate);
        exec.schedule(new Runnable() {
            private volatile Signal prevSignal = null;

            @Override
            public void run() {
                if (prevSignal == null || prevSignal == Signal.REPEAT) {
                    exec.schedule(this, rate.getMillis(), TimeUnit.MILLISECONDS);
                }

                try {
                    log.trace("Running %s (period %s)", callable, rate);
                    prevSignal = callable.call();
                } catch (Throwable e) {
                    log.error(e, "Uncaught exception.");
                }
            }
        }, initialDelay.getMillis(), TimeUnit.MILLISECONDS);
    }

    public enum Signal {
        REPEAT, STOP
    }

    public static ScheduledExecutorFactory createFactory(final Lifecycle lifecycle) {
        return (corePoolSize, nameFormat) -> ExecutorServices.manageLifecycle(lifecycle,
                fixed(corePoolSize, nameFormat));
    }

    public static ScheduledExecutorService fixed(int corePoolSize, String nameFormat) {
        return Executors.newScheduledThreadPool(corePoolSize, Execs.makeThreadFactory(nameFormat));
    }
}