001/**
002 * Logback: the reliable, generic, fast and flexible logging framework. Copyright (C) 1999-2015, QOS.ch. All rights
003 * reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under either the terms of the Eclipse Public License
006 * v1.0 as published by the Eclipse Foundation
007 *
008 * or (per the licensee's choosing)
009 *
010 * under the terms of the GNU Lesser General Public License version 2.1 as published by the Free Software Foundation.
011 */
012package ch.qos.logback.core.util;
013
014import java.lang.reflect.InvocationTargetException;
015import java.lang.reflect.Method;
016import java.util.concurrent.*;
017import java.util.concurrent.atomic.AtomicInteger;
018
019import ch.qos.logback.core.CoreConstants;
020
021/**
022 * Static utility methods for manipulating an {@link ExecutorService}.
023 *
024 * @author Carl Harris
025 * @author Mikhail Mazursky
026 */
027public class ExecutorServiceUtil {
028
029    private static final ThreadFactory THREAD_FACTORY_FOR_SCHEDULED_EXECUTION_SERVICE = new ThreadFactory() {
030
031        private final AtomicInteger threadNumber = new AtomicInteger(1);
032
033        private final ThreadFactory defaultFactory = makeThreadFactory();
034
035        /**
036         * A thread factory which may be a virtual thread factory the JDK supports it.
037         *
038         * @return
039         */
040        private ThreadFactory makeThreadFactory() {
041            return Executors.defaultThreadFactory();
042        }
043
044        @Override
045        public Thread newThread(Runnable r) {
046            Thread thread = defaultFactory.newThread(r);
047            if (!thread.isDaemon()) {
048                thread.setDaemon(true);
049            }
050            thread.setName("logback-" + threadNumber.getAndIncrement());
051            return thread;
052        }
053    };
054
055    static public ScheduledExecutorService newScheduledExecutorService() {
056        return new ScheduledThreadPoolExecutor(CoreConstants.SCHEDULED_EXECUTOR_POOL_SIZE, THREAD_FACTORY_FOR_SCHEDULED_EXECUTION_SERVICE);
057    }
058
059    /**
060     * Creates an ThreadPoolExecutor suitable for use by logback components.
061     *
062     * @since 1.4.7
063     * @return ThreadPoolExecutor
064     */
065    static public ThreadPoolExecutor newThreadPoolExecutor() {
066
067        // irrelevant parameter when LinkedBlockingQueue is in use
068        final int maximumPoolSize = CoreConstants.CORE_POOL_SIZE + 1;
069        final long keepAliveMillis = 100L;
070
071        // As of version 1.5.13, the SynchronousQueue was replaced by LinkedBlockingQueue
072        // This has the effect of queueing jobs immediately and have them run by CORE_POOL_SIZE
073        // threads. We expect jobs to arrive at a relatively slow pace compared to their duration.
074        // Note that threads are removed if idle more than keepAliveMillis
075        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(CoreConstants.CORE_POOL_SIZE, maximumPoolSize, keepAliveMillis, TimeUnit.MILLISECONDS,
076                        new LinkedBlockingQueue<>(), THREAD_FACTORY_FOR_SCHEDULED_EXECUTION_SERVICE);
077        threadPoolExecutor.allowCoreThreadTimeOut(true);
078        return threadPoolExecutor;
079
080    }
081
082    /**
083     * Shuts down an executor service.
084     * <p>
085     *
086     * @param executorService the executor service to shut down
087     */
088    static public void shutdown(ExecutorService executorService) {
089        if (executorService != null) {
090            executorService.shutdownNow();
091        }
092    }
093
094    /**
095     * An alternate implementation of {@link #newThreadPoolExecutor} which returns a virtual thread per task executor when
096     * available.
097     *
098     * @since 1.3.12/1.4.12
099     */
100    static public ExecutorService newAlternateThreadPoolExecutor() {
101        return newThreadPoolExecutor();
102    }
103}