1 // ========================================================================
2 // Copyright (c) 2004-2009 Mort Bay Consulting Pty. Ltd.
3 // ------------------------------------------------------------------------
4 // All rights reserved. This program and the accompanying materials
5 // are made available under the terms of the Eclipse Public License v1.0
6 // and Apache License v2.0 which accompanies this distribution.
7 // The Eclipse Public License is available at
8 // http://www.eclipse.org/legal/epl-v10.html
9 // The Apache License v2.0 is available at
10 // http://www.opensource.org/licenses/apache2.0.php
11 // You may elect to redistribute this code under either of these licenses.
12 // ========================================================================
13
14 package org.eclipse.jetty.util.thread;
15
16 import java.util.concurrent.ArrayBlockingQueue;
17 import java.util.concurrent.BlockingQueue;
18 import java.util.concurrent.ExecutorService;
19 import java.util.concurrent.LinkedBlockingQueue;
20 import java.util.concurrent.RejectedExecutionException;
21 import java.util.concurrent.SynchronousQueue;
22 import java.util.concurrent.ThreadPoolExecutor;
23 import java.util.concurrent.TimeUnit;
24
25 import org.eclipse.jetty.util.component.AbstractLifeCycle;
26 import org.eclipse.jetty.util.component.LifeCycle;
27 import org.eclipse.jetty.util.log.Log;
28 import org.eclipse.jetty.util.log.Logger;
29
30 /* ------------------------------------------------------------ */
31 /**
32 * Jetty ThreadPool using java 5 ThreadPoolExecutor
33 * This class wraps a {@link ExecutorService} as a {@link ThreadPool} and
34 * {@link LifeCycle} interfaces so that it may be used by the Jetty <code>org.eclipse.jetty.server.Server</code>
35 */
36 public class ExecutorThreadPool extends AbstractLifeCycle implements ThreadPool, LifeCycle
37 {
38 private static final Logger LOG = Log.getLogger(ExecutorThreadPool.class);
39 private final ExecutorService _executor;
40
41 /* ------------------------------------------------------------ */
42 public ExecutorThreadPool(ExecutorService executor)
43 {
44 _executor = executor;
45 }
46
47 /* ------------------------------------------------------------ */
48 /**
49 * Wraps an {@link ThreadPoolExecutor}.
50 * Max pool size is 256, pool thread timeout after 60 seconds and
51 * an unbounded {@link LinkedBlockingQueue} is used for the job queue;
52 */
53 public ExecutorThreadPool()
54 {
55 // Using an unbounded queue makes the maxThreads parameter useless
56 // Refer to ThreadPoolExecutor javadocs for details
57 this(new ThreadPoolExecutor(256, 256, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>()));
58 }
59
60 /* ------------------------------------------------------------ */
61 /**
62 * Wraps an {@link ThreadPoolExecutor}.
63 * Max pool size is 256, pool thread timeout after 60 seconds, and core pool size is 32 when queueSize >= 0.
64 * @param queueSize can be -1 for using an unbounded {@link LinkedBlockingQueue}, 0 for using a
65 * {@link SynchronousQueue}, greater than 0 for using a {@link ArrayBlockingQueue} of the given size.
66 */
67 public ExecutorThreadPool(int queueSize)
68 {
69 this(queueSize < 0 ? new ThreadPoolExecutor(256, 256, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>()) :
70 queueSize == 0 ? new ThreadPoolExecutor(32, 256, 60, TimeUnit.SECONDS, new SynchronousQueue<Runnable>()) :
71 new ThreadPoolExecutor(32, 256, 60, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(queueSize)));
72 }
73
74 /* ------------------------------------------------------------ */
75 /**
76 * Wraps an {@link ThreadPoolExecutor} using
77 * an unbounded {@link LinkedBlockingQueue} is used for the jobs queue;
78 * @param corePoolSize must be equal to maximumPoolSize
79 * @param maximumPoolSize the maximum number of threads to allow in the pool
80 * @param keepAliveTime the max time a thread can remain idle, in milliseconds
81 */
82 public ExecutorThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime)
83 {
84 this(corePoolSize, maximumPoolSize, keepAliveTime, TimeUnit.MILLISECONDS);
85 }
86
87 /* ------------------------------------------------------------ */
88 /**
89 * Wraps an {@link ThreadPoolExecutor} using
90 * an unbounded {@link LinkedBlockingQueue} is used for the jobs queue.
91 * @param corePoolSize must be equal to maximumPoolSize
92 * @param maximumPoolSize the maximum number of threads to allow in the pool
93 * @param keepAliveTime the max time a thread can remain idle
94 * @param unit the unit for the keepAliveTime
95 */
96 public ExecutorThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit)
97 {
98 this(corePoolSize, maximumPoolSize, keepAliveTime, unit, new LinkedBlockingQueue<Runnable>());
99 }
100
101 /* ------------------------------------------------------------ */
102
103 /**
104 * Wraps an {@link ThreadPoolExecutor}
105 * @param corePoolSize the number of threads to keep in the pool, even if they are idle
106 * @param maximumPoolSize the maximum number of threads to allow in the pool
107 * @param keepAliveTime the max time a thread can remain idle
108 * @param unit the unit for the keepAliveTime
109 * @param workQueue the queue to use for holding tasks before they are executed
110 */
111 public ExecutorThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue)
112 {
113 this(new ThreadPoolExecutor(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue));
114 }
115
116 /* ------------------------------------------------------------ */
117 public boolean dispatch(Runnable job)
118 {
119 try
120 {
121 _executor.execute(job);
122 return true;
123 }
124 catch(RejectedExecutionException e)
125 {
126 LOG.warn(e);
127 return false;
128 }
129 }
130
131 /* ------------------------------------------------------------ */
132 public int getIdleThreads()
133 {
134 if (_executor instanceof ThreadPoolExecutor)
135 {
136 final ThreadPoolExecutor tpe = (ThreadPoolExecutor)_executor;
137 return tpe.getPoolSize() - tpe.getActiveCount();
138 }
139 return -1;
140 }
141
142 /* ------------------------------------------------------------ */
143 public int getThreads()
144 {
145 if (_executor instanceof ThreadPoolExecutor)
146 {
147 final ThreadPoolExecutor tpe = (ThreadPoolExecutor)_executor;
148 return tpe.getPoolSize();
149 }
150 return -1;
151 }
152
153 /* ------------------------------------------------------------ */
154 public boolean isLowOnThreads()
155 {
156 if (_executor instanceof ThreadPoolExecutor)
157 {
158 final ThreadPoolExecutor tpe = (ThreadPoolExecutor)_executor;
159 // getActiveCount() locks the thread pool, so execute it last
160 return tpe.getPoolSize() == tpe.getMaximumPoolSize() &&
161 tpe.getQueue().size() >= tpe.getPoolSize() - tpe.getActiveCount();
162 }
163 return false;
164 }
165
166 /* ------------------------------------------------------------ */
167 public void join() throws InterruptedException
168 {
169 _executor.awaitTermination(Long.MAX_VALUE, TimeUnit.MILLISECONDS);
170 }
171
172 /* ------------------------------------------------------------ */
173 @Override
174 protected void doStop() throws Exception
175 {
176 super.doStop();
177 _executor.shutdownNow();
178 }
179 }