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.activemq.thread; 018 019 import java.util.concurrent.Executor; 020 import java.util.concurrent.ExecutorService; 021 import java.util.concurrent.SynchronousQueue; 022 import java.util.concurrent.ThreadFactory; 023 import java.util.concurrent.ThreadPoolExecutor; 024 import java.util.concurrent.TimeUnit; 025 import java.util.concurrent.atomic.AtomicLong; 026 027 /** 028 * Manages the thread pool for long running tasks. Long running tasks are not 029 * always active but when they are active, they may need a few iterations of 030 * processing for them to become idle. The manager ensures that each task is 031 * processes but that no one task overtakes the system. This is kinda like 032 * cooperative multitasking. 033 * 034 * 035 */ 036 public class TaskRunnerFactory implements Executor { 037 038 private ExecutorService executor; 039 private int maxIterationsPerRun; 040 private String name; 041 private int priority; 042 private boolean daemon; 043 private AtomicLong id = new AtomicLong(0); 044 045 public TaskRunnerFactory() { 046 this("ActiveMQ Task", Thread.NORM_PRIORITY, true, 1000); 047 } 048 049 private TaskRunnerFactory(String name, int priority, boolean daemon, int maxIterationsPerRun) { 050 this(name,priority,daemon,maxIterationsPerRun,false); 051 } 052 053 054 public TaskRunnerFactory(String name, int priority, boolean daemon, int maxIterationsPerRun, boolean dedicatedTaskRunner) { 055 056 this.name = name; 057 this.priority = priority; 058 this.daemon = daemon; 059 this.maxIterationsPerRun = maxIterationsPerRun; 060 061 // If your OS/JVM combination has a good thread model, you may want to 062 // avoid 063 // using a thread pool to run tasks and use a DedicatedTaskRunner 064 // instead. 065 if (dedicatedTaskRunner || "true".equalsIgnoreCase(System.getProperty("org.apache.activemq.UseDedicatedTaskRunner"))) { 066 executor = null; 067 } else { 068 executor = createDefaultExecutor(); 069 } 070 } 071 072 public void shutdown() { 073 if (executor != null) { 074 executor.shutdownNow(); 075 } 076 } 077 078 public TaskRunner createTaskRunner(Task task, String name) { 079 if (executor != null) { 080 return new PooledTaskRunner(executor, task, maxIterationsPerRun); 081 } else { 082 return new DedicatedTaskRunner(task, name, priority, daemon); 083 } 084 } 085 086 public void execute(Runnable runnable) { 087 execute(runnable, "ActiveMQ Task"); 088 } 089 090 public void execute(Runnable runnable, String name) { 091 if (executor != null) { 092 executor.execute(runnable); 093 } else { 094 new Thread(runnable, name + "-" + id.incrementAndGet()).start(); 095 } 096 } 097 098 protected ExecutorService createDefaultExecutor() { 099 ThreadPoolExecutor rc = new ThreadPoolExecutor(0, Integer.MAX_VALUE, 10, TimeUnit.SECONDS, new SynchronousQueue<Runnable>(), new ThreadFactory() { 100 public Thread newThread(Runnable runnable) { 101 Thread thread = new Thread(runnable, name + "-" + id.incrementAndGet()); 102 thread.setDaemon(daemon); 103 thread.setPriority(priority); 104 return thread; 105 } 106 }); 107 // rc.allowCoreThreadTimeOut(true); 108 return rc; 109 } 110 111 }