| /* |
| * Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package sun.nio.ch; |
| |
| import java.util.concurrent.*; |
| import java.security.AccessController; |
| import sun.security.action.GetPropertyAction; |
| import sun.security.action.GetIntegerAction; |
| |
| /** |
| * Encapsulates a thread pool associated with a channel group. |
| */ |
| |
| public class ThreadPool { |
| private static final String DEFAULT_THREAD_POOL_THREAD_FACTORY = |
| "java.nio.channels.DefaultThreadPool.threadFactory"; |
| private static final String DEFAULT_THREAD_POOL_INITIAL_SIZE = |
| "java.nio.channels.DefaultThreadPool.initialSize"; |
| private static final ThreadFactory defaultThreadFactory = new ThreadFactory() { |
| @Override |
| public Thread newThread(Runnable r) { |
| Thread t = new Thread(r); |
| t.setDaemon(true); |
| return t; |
| } |
| }; |
| |
| private final ExecutorService executor; |
| |
| // indicates if thread pool is fixed size |
| private final boolean isFixed; |
| |
| // indicates the pool size (for a fixed thread pool configuratin this is |
| // the maximum pool size; for other thread pools it is the initial size) |
| private final int poolSize; |
| |
| private ThreadPool(ExecutorService executor, |
| boolean isFixed, |
| int poolSize) |
| { |
| this.executor = executor; |
| this.isFixed = isFixed; |
| this.poolSize = poolSize; |
| } |
| |
| ExecutorService executor() { |
| return executor; |
| } |
| |
| boolean isFixedThreadPool() { |
| return isFixed; |
| } |
| |
| int poolSize() { |
| return poolSize; |
| } |
| |
| static ThreadFactory defaultThreadFactory() { |
| return defaultThreadFactory; |
| } |
| |
| private static class DefaultThreadPoolHolder { |
| final static ThreadPool defaultThreadPool = createDefault(); |
| } |
| |
| // return the default (system-wide) thread pool |
| static ThreadPool getDefault() { |
| return DefaultThreadPoolHolder.defaultThreadPool; |
| } |
| |
| // create thread using default settings (configured by system properties) |
| static ThreadPool createDefault() { |
| // default the number of fixed threads to the hardware core count |
| int initialSize = getDefaultThreadPoolInitialSize(); |
| if (initialSize < 0) |
| initialSize = Runtime.getRuntime().availableProcessors(); |
| // default to thread factory that creates daemon threads |
| ThreadFactory threadFactory = getDefaultThreadPoolThreadFactory(); |
| if (threadFactory == null) |
| threadFactory = defaultThreadFactory; |
| // create thread pool |
| ExecutorService executor = |
| new ThreadPoolExecutor(0, Integer.MAX_VALUE, |
| Long.MAX_VALUE, TimeUnit.MILLISECONDS, |
| new SynchronousQueue<Runnable>(), |
| threadFactory); |
| return new ThreadPool(executor, false, initialSize); |
| } |
| |
| // create using given parameters |
| static ThreadPool create(int nThreads, ThreadFactory factory) { |
| if (nThreads <= 0) |
| throw new IllegalArgumentException("'nThreads' must be > 0"); |
| ExecutorService executor = Executors.newFixedThreadPool(nThreads, factory); |
| return new ThreadPool(executor, true, nThreads); |
| } |
| |
| // wrap a user-supplied executor |
| public static ThreadPool wrap(ExecutorService executor, int initialSize) { |
| if (executor == null) |
| throw new NullPointerException("'executor' is null"); |
| // attempt to check if cached thread pool |
| if (executor instanceof ThreadPoolExecutor) { |
| int max = ((ThreadPoolExecutor)executor).getMaximumPoolSize(); |
| if (max == Integer.MAX_VALUE) { |
| if (initialSize < 0) { |
| initialSize = Runtime.getRuntime().availableProcessors(); |
| } else { |
| // not a cached thread pool so ignore initial size |
| initialSize = 0; |
| } |
| } |
| } else { |
| // some other type of thread pool |
| if (initialSize < 0) |
| initialSize = 0; |
| } |
| return new ThreadPool(executor, false, initialSize); |
| } |
| |
| private static int getDefaultThreadPoolInitialSize() { |
| String propValue = AccessController.doPrivileged(new |
| GetPropertyAction(DEFAULT_THREAD_POOL_INITIAL_SIZE)); |
| if (propValue != null) { |
| try { |
| return Integer.parseInt(propValue); |
| } catch (NumberFormatException x) { |
| throw new Error("Value of property '" + DEFAULT_THREAD_POOL_INITIAL_SIZE + |
| "' is invalid: " + x); |
| } |
| } |
| return -1; |
| } |
| |
| private static ThreadFactory getDefaultThreadPoolThreadFactory() { |
| String propValue = AccessController.doPrivileged(new |
| GetPropertyAction(DEFAULT_THREAD_POOL_THREAD_FACTORY)); |
| if (propValue != null) { |
| try { |
| Class<?> c = Class |
| .forName(propValue, true, ClassLoader.getSystemClassLoader()); |
| return ((ThreadFactory)c.newInstance()); |
| } catch (ClassNotFoundException x) { |
| throw new Error(x); |
| } catch (InstantiationException x) { |
| throw new Error(x); |
| } catch (IllegalAccessException x) { |
| throw new Error(x); |
| } |
| } |
| return null; |
| } |
| } |