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| 1 | /* | ||
| 2 | * Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package sun.nio.ch; | ||
| 27 | |||
| 28 | import java.util.concurrent.*; | ||
| 29 | import java.security.AccessController; | ||
| 30 | import sun.security.action.GetPropertyAction; | ||
| 31 | import sun.security.action.GetIntegerAction; | ||
| 32 | |||
| 33 | /** | ||
| 34 | * Encapsulates a thread pool associated with a channel group. | ||
| 35 | */ | ||
| 36 | |||
| 37 | public class ThreadPool { | ||
| 38 | private static final String DEFAULT_THREAD_POOL_THREAD_FACTORY = | ||
| 39 | "java.nio.channels.DefaultThreadPool.threadFactory"; | ||
| 40 | private static final String DEFAULT_THREAD_POOL_INITIAL_SIZE = | ||
| 41 | "java.nio.channels.DefaultThreadPool.initialSize"; | ||
| 42 | private static final ThreadFactory defaultThreadFactory = new ThreadFactory() { | ||
| 43 | @Override | ||
| 44 | public Thread newThread(Runnable r) { | ||
| 45 | Thread t = new Thread(r); | ||
| 46 | t.setDaemon(true); | ||
| 47 | return t; | ||
| 48 | } | ||
| 49 | }; | ||
| 50 | |||
| 51 | private final ExecutorService executor; | ||
| 52 | |||
| 53 | // indicates if thread pool is fixed size | ||
| 54 | private final boolean isFixed; | ||
| 55 | |||
| 56 | // indicates the pool size (for a fixed thread pool configuratin this is | ||
| 57 | // the maximum pool size; for other thread pools it is the initial size) | ||
| 58 | private final int poolSize; | ||
| 59 | |||
| 60 | private ThreadPool(ExecutorService executor, | ||
| 61 | boolean isFixed, | ||
| 62 | int poolSize) | ||
| 63 | { | ||
| 64 | this.executor = executor; | ||
| 65 | this.isFixed = isFixed; | ||
| 66 | this.poolSize = poolSize; | ||
| 67 | } | ||
| 68 | |||
| 69 | ExecutorService executor() { | ||
| 70 | return executor; | ||
| 71 | } | ||
| 72 | |||
| 73 | boolean isFixedThreadPool() { | ||
| 74 | return isFixed; | ||
| 75 | } | ||
| 76 | |||
| 77 | int poolSize() { | ||
| 78 | return poolSize; | ||
| 79 | } | ||
| 80 | |||
| 81 | static ThreadFactory defaultThreadFactory() { | ||
| 82 | return defaultThreadFactory; | ||
| 83 | } | ||
| 84 | |||
| 85 | private static class DefaultThreadPoolHolder { | ||
| 86 | final static ThreadPool defaultThreadPool = createDefault(); | ||
| 87 | } | ||
| 88 | |||
| 89 | // return the default (system-wide) thread pool | ||
| 90 | static ThreadPool getDefault() { | ||
| 91 | return DefaultThreadPoolHolder.defaultThreadPool; | ||
| 92 | } | ||
| 93 | |||
| 94 | // create thread using default settings (configured by system properties) | ||
| 95 | static ThreadPool createDefault() { | ||
| 96 | // default the number of fixed threads to the hardware core count | ||
| 97 | int initialSize = getDefaultThreadPoolInitialSize(); | ||
| 98 | if (initialSize < 0) | ||
| 99 | initialSize = Runtime.getRuntime().availableProcessors(); | ||
| 100 | // default to thread factory that creates daemon threads | ||
| 101 | ThreadFactory threadFactory = getDefaultThreadPoolThreadFactory(); | ||
| 102 | if (threadFactory == null) | ||
| 103 | threadFactory = defaultThreadFactory; | ||
| 104 | // create thread pool | ||
| 105 | ExecutorService executor = | ||
| 106 | new ThreadPoolExecutor(0, Integer.MAX_VALUE, | ||
| 107 | Long.MAX_VALUE, TimeUnit.MILLISECONDS, | ||
| 108 | new SynchronousQueue<Runnable>(), | ||
| 109 | threadFactory); | ||
| 110 | return new ThreadPool(executor, false, initialSize); | ||
| 111 | } | ||
| 112 | |||
| 113 | // create using given parameters | ||
| 114 | static ThreadPool create(int nThreads, ThreadFactory factory) { | ||
| 115 | if (nThreads <= 0) | ||
| 116 | throw new IllegalArgumentException("'nThreads' must be > 0"); | ||
| 117 | ExecutorService executor = Executors.newFixedThreadPool(nThreads, factory); | ||
| 118 | return new ThreadPool(executor, true, nThreads); | ||
| 119 | } | ||
| 120 | |||
| 121 | // wrap a user-supplied executor | ||
| 122 | public static ThreadPool wrap(ExecutorService executor, int initialSize) { | ||
| 123 | if (executor == null) | ||
| 124 | throw new NullPointerException("'executor' is null"); | ||
| 125 | // attempt to check if cached thread pool | ||
| 126 | if (executor instanceof ThreadPoolExecutor) { | ||
| 127 | int max = ((ThreadPoolExecutor)executor).getMaximumPoolSize(); | ||
| 128 | if (max == Integer.MAX_VALUE) { | ||
| 129 | if (initialSize < 0) { | ||
| 130 | initialSize = Runtime.getRuntime().availableProcessors(); | ||
| 131 | } else { | ||
| 132 | // not a cached thread pool so ignore initial size | ||
| 133 | initialSize = 0; | ||
| 134 | } | ||
| 135 | } | ||
| 136 | } else { | ||
| 137 | // some other type of thread pool | ||
| 138 | if (initialSize < 0) | ||
| 139 | initialSize = 0; | ||
| 140 | } | ||
| 141 | return new ThreadPool(executor, false, initialSize); | ||
| 142 | } | ||
| 143 | |||
| 144 | private static int getDefaultThreadPoolInitialSize() { | ||
| 145 | String propValue = AccessController.doPrivileged(new | ||
| 146 | GetPropertyAction(DEFAULT_THREAD_POOL_INITIAL_SIZE)); | ||
| 147 | if (propValue != null) { | ||
| 148 | try { | ||
| 149 | return Integer.parseInt(propValue); | ||
| 150 | } catch (NumberFormatException x) { | ||
| 151 | throw new Error("Value of property '" + DEFAULT_THREAD_POOL_INITIAL_SIZE + | ||
| 152 | "' is invalid: " + x); | ||
| 153 | } | ||
| 154 | } | ||
| 155 | return -1; | ||
| 156 | } | ||
| 157 | |||
| 158 | private static ThreadFactory getDefaultThreadPoolThreadFactory() { | ||
| 159 | String propValue = AccessController.doPrivileged(new | ||
| 160 | GetPropertyAction(DEFAULT_THREAD_POOL_THREAD_FACTORY)); | ||
| 161 | if (propValue != null) { | ||
| 162 | try { | ||
| 163 | Class<?> c = Class | ||
| 164 | .forName(propValue, true, ClassLoader.getSystemClassLoader()); | ||
| 165 | return ((ThreadFactory)c.newInstance()); | ||
| 166 | } catch (ClassNotFoundException x) { | ||
| 167 | throw new Error(x); | ||
| 168 | } catch (InstantiationException x) { | ||
| 169 | throw new Error(x); | ||
| 170 | } catch (IllegalAccessException x) { | ||
| 171 | throw new Error(x); | ||
| 172 | } | ||
| 173 | } | ||
| 174 | return null; | ||
| 175 | } | ||
| 176 | } | ||