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 */
017 package org.apache.camel.impl;
018
019 import java.util.concurrent.BlockingQueue;
020 import java.util.concurrent.ExecutorService;
021 import java.util.concurrent.Executors;
022 import java.util.concurrent.LinkedBlockingQueue;
023 import java.util.concurrent.RejectedExecutionHandler;
024 import java.util.concurrent.ScheduledExecutorService;
025 import java.util.concurrent.ScheduledThreadPoolExecutor;
026 import java.util.concurrent.SynchronousQueue;
027 import java.util.concurrent.ThreadFactory;
028 import java.util.concurrent.ThreadPoolExecutor;
029 import java.util.concurrent.TimeUnit;
030
031 import org.apache.camel.spi.ThreadPoolFactory;
032 import org.apache.camel.spi.ThreadPoolProfile;
033 import org.apache.camel.util.concurrent.RejectableScheduledThreadPoolExecutor;
034 import org.apache.camel.util.concurrent.RejectableThreadPoolExecutor;
035 import org.apache.camel.util.concurrent.SizedScheduledExecutorService;
036
037 /**
038 * Factory for thread pools that uses the JDK {@link Executors} for creating the thread pools.
039 */
040 public class DefaultThreadPoolFactory implements ThreadPoolFactory {
041
042 public ExecutorService newCachedThreadPool(ThreadFactory threadFactory) {
043 return Executors.newCachedThreadPool(threadFactory);
044 }
045
046 @Override
047 public ExecutorService newThreadPool(ThreadPoolProfile profile, ThreadFactory factory) {
048 return newThreadPool(profile.getPoolSize(),
049 profile.getMaxPoolSize(),
050 profile.getKeepAliveTime(),
051 profile.getTimeUnit(),
052 profile.getMaxQueueSize(),
053 profile.getRejectedExecutionHandler(),
054 factory);
055 }
056
057 public ExecutorService newThreadPool(int corePoolSize, int maxPoolSize, long keepAliveTime, TimeUnit timeUnit,
058 int maxQueueSize, RejectedExecutionHandler rejectedExecutionHandler,
059 ThreadFactory threadFactory) throws IllegalArgumentException {
060
061 // the core pool size must be higher than 0
062 if (corePoolSize < 1) {
063 throw new IllegalArgumentException("CorePoolSize must be >= 1, was " + corePoolSize);
064 }
065
066 // validate max >= core
067 if (maxPoolSize < corePoolSize) {
068 throw new IllegalArgumentException("MaxPoolSize must be >= corePoolSize, was " + maxPoolSize + " >= " + corePoolSize);
069 }
070
071 BlockingQueue<Runnable> workQueue;
072 if (corePoolSize == 0 && maxQueueSize <= 0) {
073 // use a synchronous queue for direct-handover (no tasks stored on the queue)
074 workQueue = new SynchronousQueue<Runnable>();
075 // and force 1 as pool size to be able to create the thread pool by the JDK
076 corePoolSize = 1;
077 maxPoolSize = 1;
078 } else if (maxQueueSize <= 0) {
079 // use a synchronous queue for direct-handover (no tasks stored on the queue)
080 workQueue = new SynchronousQueue<Runnable>();
081 } else {
082 // bounded task queue to store tasks on the queue
083 workQueue = new LinkedBlockingQueue<Runnable>(maxQueueSize);
084 }
085
086 ThreadPoolExecutor answer = new RejectableThreadPoolExecutor(corePoolSize, maxPoolSize, keepAliveTime, timeUnit, workQueue);
087 answer.setThreadFactory(threadFactory);
088 if (rejectedExecutionHandler == null) {
089 rejectedExecutionHandler = new ThreadPoolExecutor.CallerRunsPolicy();
090 }
091 answer.setRejectedExecutionHandler(rejectedExecutionHandler);
092 return answer;
093 }
094
095 @Override
096 public ScheduledExecutorService newScheduledThreadPool(ThreadPoolProfile profile, ThreadFactory threadFactory) {
097 RejectedExecutionHandler rejectedExecutionHandler = profile.getRejectedExecutionHandler();
098 if (rejectedExecutionHandler == null) {
099 rejectedExecutionHandler = new ThreadPoolExecutor.CallerRunsPolicy();
100 }
101
102 ScheduledThreadPoolExecutor answer = new RejectableScheduledThreadPoolExecutor(profile.getPoolSize(), threadFactory, rejectedExecutionHandler);
103 // TODO: when JDK7 we should setRemoveOnCancelPolicy(true)
104
105 // need to wrap the thread pool in a sized to guard against the problem that the
106 // JDK created thread pool has an unbounded queue (see class javadoc), which mean
107 // we could potentially keep adding tasks, and run out of memory.
108 if (profile.getMaxPoolSize() > 0) {
109 return new SizedScheduledExecutorService(answer, profile.getMaxQueueSize());
110 } else {
111 return answer;
112 }
113 }
114
115 }