001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.activemq.util; 018 019import java.util.List; 020import java.util.concurrent.ExecutorService; 021import java.util.concurrent.TimeUnit; 022 023import org.slf4j.Logger; 024import org.slf4j.LoggerFactory; 025 026/** 027 * Utility methods for working with thread pools {@link ExecutorService}. 028 */ 029public final class ThreadPoolUtils { 030 031 private static final Logger LOG = LoggerFactory.getLogger(ThreadPoolUtils.class); 032 033 public static final long DEFAULT_SHUTDOWN_AWAIT_TERMINATION = 10 * 1000L; 034 035 /** 036 * Shutdown the given executor service only (ie not graceful shutdown). 037 * 038 * @see java.util.concurrent.ExecutorService#shutdown() 039 */ 040 public static void shutdown(ExecutorService executorService) { 041 doShutdown(executorService, 0); 042 } 043 044 /** 045 * Shutdown now the given executor service aggressively. 046 * 047 * @param executorService the executor service to shutdown now 048 * @return list of tasks that never commenced execution 049 * @see java.util.concurrent.ExecutorService#shutdownNow() 050 */ 051 public static List<Runnable> shutdownNow(ExecutorService executorService) { 052 List<Runnable> answer = null; 053 if (!executorService.isShutdown()) { 054 LOG.debug("Forcing shutdown of ExecutorService: {}", executorService); 055 answer = executorService.shutdownNow(); 056 if (LOG.isTraceEnabled()) { 057 LOG.trace("Shutdown of ExecutorService: {} is shutdown: {} and terminated: {}.", 058 new Object[]{executorService, executorService.isShutdown(), executorService.isTerminated()}); 059 } 060 } 061 062 return answer; 063 } 064 065 /** 066 * Shutdown the given executor service graceful at first, and then aggressively 067 * if the await termination timeout was hit. 068 * <p/> 069 * This implementation invokes the {@link #shutdownGraceful(java.util.concurrent.ExecutorService, long)} 070 * with a timeout value of {@link #DEFAULT_SHUTDOWN_AWAIT_TERMINATION} millis. 071 */ 072 public static void shutdownGraceful(ExecutorService executorService) { 073 doShutdown(executorService, DEFAULT_SHUTDOWN_AWAIT_TERMINATION); 074 } 075 076 /** 077 * Shutdown the given executor service graceful at first, and then aggressively 078 * if the await termination timeout was hit. 079 * <p/> 080 * Will try to perform an orderly shutdown by giving the running threads 081 * time to complete tasks, before going more aggressively by doing a 082 * {@link #shutdownNow(java.util.concurrent.ExecutorService)} which 083 * forces a shutdown. The parameter <tt>shutdownAwaitTermination</tt> 084 * is used as timeout value waiting for orderly shutdown to 085 * complete normally, before going aggressively. 086 * 087 * @param executorService the executor service to shutdown 088 * @param shutdownAwaitTermination timeout in millis to wait for orderly shutdown 089 */ 090 public static void shutdownGraceful(ExecutorService executorService, long shutdownAwaitTermination) { 091 doShutdown(executorService, shutdownAwaitTermination); 092 } 093 094 private static void doShutdown(ExecutorService executorService, long shutdownAwaitTermination) { 095 // code from Apache Camel - org.apache.camel.impl.DefaultExecutorServiceManager 096 097 if (executorService == null) { 098 return; 099 } 100 101 // shutting down a thread pool is a 2 step process. First we try graceful, and if that fails, then we go more aggressively 102 // and try shutting down again. In both cases we wait at most the given shutdown timeout value given 103 // (total wait could then be 2 x shutdownAwaitTermination, but when we shutdown the 2nd time we are aggressive and thus 104 // we ought to shutdown much faster) 105 if (!executorService.isShutdown()) { 106 boolean warned = false; 107 StopWatch watch = new StopWatch(); 108 109 LOG.trace("Shutdown of ExecutorService: {} with await termination: {} millis", executorService, shutdownAwaitTermination); 110 executorService.shutdown(); 111 112 if (shutdownAwaitTermination > 0) { 113 try { 114 if (!awaitTermination(executorService, shutdownAwaitTermination)) { 115 warned = true; 116 LOG.warn("Forcing shutdown of ExecutorService: {} due first await termination elapsed.", executorService); 117 executorService.shutdownNow(); 118 // we are now shutting down aggressively, so wait to see if we can completely shutdown or not 119 if (!awaitTermination(executorService, shutdownAwaitTermination)) { 120 LOG.warn("Cannot completely force shutdown of ExecutorService: {} due second await termination elapsed.", executorService); 121 } 122 } 123 } catch (InterruptedException e) { 124 warned = true; 125 LOG.warn("Forcing shutdown of ExecutorService: {} due interrupted.", executorService); 126 // we were interrupted during shutdown, so force shutdown 127 try { 128 executorService.shutdownNow(); 129 } finally { 130 Thread.currentThread().interrupt(); 131 } 132 } 133 } 134 135 // if we logged at WARN level, then report at INFO level when we are complete so the end user can see this in the log 136 if (warned) { 137 LOG.info("Shutdown of ExecutorService: {} is shutdown: {} and terminated: {} took: {}.", 138 new Object[]{executorService, executorService.isShutdown(), executorService.isTerminated(), TimeUtils.printDuration(watch.taken())}); 139 } else if (LOG.isDebugEnabled()) { 140 LOG.debug("Shutdown of ExecutorService: {} is shutdown: {} and terminated: {} took: {}.", 141 new Object[]{executorService, executorService.isShutdown(), executorService.isTerminated(), TimeUtils.printDuration(watch.taken())}); 142 } 143 } 144 } 145 146 /** 147 * Awaits the termination of the thread pool. 148 * <p/> 149 * This implementation will log every 2nd second at INFO level that we are waiting, so the end user 150 * can see we are not hanging in case it takes longer time to terminate the pool. 151 * 152 * @param executorService the thread pool 153 * @param shutdownAwaitTermination time in millis to use as timeout 154 * @return <tt>true</tt> if the pool is terminated, or <tt>false</tt> if we timed out 155 * @throws InterruptedException is thrown if we are interrupted during the waiting 156 */ 157 public static boolean awaitTermination(ExecutorService executorService, long shutdownAwaitTermination) throws InterruptedException { 158 // log progress every 5th second so end user is aware of we are shutting down 159 StopWatch watch = new StopWatch(); 160 long interval = Math.min(2000, shutdownAwaitTermination); 161 boolean done = false; 162 while (!done && interval > 0) { 163 if (executorService.awaitTermination(interval, TimeUnit.MILLISECONDS)) { 164 done = true; 165 } else { 166 LOG.info("Waited {} for ExecutorService: {} to terminate...", TimeUtils.printDuration(watch.taken()), executorService); 167 // recalculate interval 168 interval = Math.min(2000, shutdownAwaitTermination - watch.taken()); 169 } 170 } 171 172 return done; 173 } 174}