sg.atom.utils.execution.ScheduledExecutors.java Source code

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Here is the source code for sg.atom.utils.execution.ScheduledExecutors.java

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/*
 * Copyright 2011,2012 Metamarkets Group Inc.
 *
 * Licensed 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 sg.atom.utils.execution;

import sg.atom.utils.execution.services.ExecutorServices;
import com.google.common.util.concurrent.ThreadFactoryBuilder;
import sg.atom.utils.execution.lifecycle.Lifecycle;
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;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ScheduledExecutors {

    private static final Logger log = LoggerFactory.getLogger(ScheduledExecutors.class);

    /**
     * Run runnable repeatedly with the given delay between calls. Exceptions
     * are caught and logged as errors.
     */
    public static void scheduleWithFixedDelay(ScheduledExecutorService exec, Duration delay, Runnable runnable) {
        scheduleWithFixedDelay(exec, delay, delay, runnable);
    }

    /**
     * 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.debug("Running %s (delay %s)", callable, delay);
                    if (callable.call() == Signal.REPEAT) {
                        log.debug("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("Uncaught exception.");
                }
            }
        }, initialDelay.getMillis(), TimeUnit.MILLISECONDS);
    }

    /**
     * Run runnable once every period. Exceptions are caught and logged as
     * errors.
     */
    public static void scheduleAtFixedRate(ScheduledExecutorService exec, Duration rate, Runnable runnable) {
        scheduleAtFixedRate(exec, rate, rate, runnable);
    }

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

    public static enum Signal {

        REPEAT, STOP
    }

    public static ScheduledExecutorFactory createFactory(final Lifecycle lifecycle) {
        return new ScheduledExecutorFactory() {
            public ScheduledExecutorService create(int corePoolSize, String nameFormat) {
                return ExecutorServices.manageLifecycle(lifecycle, fixed(corePoolSize, nameFormat));
            }
        };
    }

    public static ScheduledExecutorService fixed(int corePoolSize, String nameFormat) {
        return Executors.newScheduledThreadPool(corePoolSize,
                new ThreadFactoryBuilder().setDaemon(true).setNameFormat(nameFormat).build());
    }
}