| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.sshd.common.util.threads; |
| |
| import java.lang.reflect.InvocationHandler; |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Proxy; |
| import java.security.AccessController; |
| import java.security.PrivilegedActionException; |
| import java.security.PrivilegedExceptionAction; |
| import java.util.Collections; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.LinkedBlockingQueue; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.ScheduledThreadPoolExecutor; |
| import java.util.concurrent.SynchronousQueue; |
| import java.util.concurrent.ThreadFactory; |
| import java.util.concurrent.ThreadPoolExecutor; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| import java.util.concurrent.atomic.AtomicInteger; |
| |
| import org.apache.sshd.common.util.logging.AbstractLoggingBean; |
| |
| /** |
| * Utility class for thread pools. |
| * |
| * @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a> |
| */ |
| public final class ThreadUtils { |
| |
| private ThreadUtils() { |
| throw new UnsupportedOperationException("No instance"); |
| } |
| |
| /** |
| * Wraps an {@link ExecutorService} in such a way as to "protect" |
| * it for calls to the {@link ExecutorService#shutdown()} or |
| * {@link ExecutorService#shutdownNow()}. All other calls are delegated as-is |
| * to the original service. <B>Note:</B> the exposed wrapped proxy will |
| * answer correctly the {@link ExecutorService#isShutdown()} query if indeed |
| * one of the {@code shutdown} methods was invoked. |
| * |
| * @param executorService The original service - ignored if {@code null} |
| * @param shutdownOnExit If {@code true} then it is OK to shutdown the executor |
| * so no wrapping takes place. |
| * @return Either the original service or a wrapped one - depending on the |
| * value of the <tt>shutdownOnExit</tt> parameter |
| */ |
| public static ExecutorService protectExecutorServiceShutdown(final ExecutorService executorService, boolean shutdownOnExit) { |
| if (executorService == null || shutdownOnExit) { |
| return executorService; |
| } else { |
| return (ExecutorService) Proxy.newProxyInstance( |
| resolveDefaultClassLoader(executorService), |
| new Class<?>[]{ExecutorService.class}, |
| new InvocationHandler() { |
| private final AtomicBoolean stopped = new AtomicBoolean(false); |
| |
| @Override |
| public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { |
| String name = method.getName(); |
| if ("isShutdown".equals(name)) { |
| return stopped.get(); |
| } else if ("shutdown".equals(name)) { |
| stopped.set(true); |
| return null; // void... |
| } else if ("shutdownNow".equals(name)) { |
| stopped.set(true); |
| return Collections.emptyList(); |
| } else { |
| return method.invoke(executorService, args); |
| } |
| } |
| }); |
| } |
| } |
| |
| public static ClassLoader resolveDefaultClassLoader(Object anchor) { |
| return resolveDefaultClassLoader(anchor == null ? null : anchor.getClass()); |
| } |
| |
| /** |
| * <P>Attempts to find the most suitable {@link ClassLoader} as follows:</P> |
| * <UL> |
| * <LI><P> |
| * Check the {@link Thread#getContextClassLoader()} value |
| * </P></LI> |
| * |
| * <LI><P> |
| * If no thread context class loader then check the anchor |
| * class (if given) for its class loader |
| * </P></LI> |
| * |
| * <LI><P> |
| * If still no loader available, then use {@link ClassLoader#getSystemClassLoader()} |
| * </P></LI> |
| * </UL> |
| * |
| * @param anchor The anchor {@link Class} to use if no current thread |
| * - ignored if {@code null} |
| * context class loader |
| * @return The resolver {@link ClassLoader} |
| */ |
| public static ClassLoader resolveDefaultClassLoader(Class<?> anchor) { |
| Thread thread = Thread.currentThread(); |
| ClassLoader cl = thread.getContextClassLoader(); |
| if (cl != null) { |
| return cl; |
| } |
| |
| if (anchor != null) { |
| cl = anchor.getClassLoader(); |
| } |
| |
| if (cl == null) { // can happen for core Java classes |
| cl = ClassLoader.getSystemClassLoader(); |
| } |
| |
| return cl; |
| } |
| |
| public static ExecutorService newFixedThreadPool(String poolName, int nThreads) { |
| return new ThreadPoolExecutor(nThreads, nThreads, |
| 0L, TimeUnit.MILLISECONDS, // TODO make this configurable |
| new LinkedBlockingQueue<Runnable>(), |
| new SshdThreadFactory(poolName), |
| new ThreadPoolExecutor.CallerRunsPolicy()); |
| } |
| |
| public static ExecutorService newCachedThreadPool(String poolName) { |
| return new ThreadPoolExecutor(0, Integer.MAX_VALUE, // TODO make this configurable |
| 60L, TimeUnit.SECONDS, // TODO make this configurable |
| new SynchronousQueue<Runnable>(), |
| new SshdThreadFactory(poolName), |
| new ThreadPoolExecutor.CallerRunsPolicy()); |
| } |
| |
| public static ScheduledExecutorService newSingleThreadScheduledExecutor(String poolName) { |
| return new ScheduledThreadPoolExecutor(1, new SshdThreadFactory(poolName)); |
| } |
| |
| public static ExecutorService newSingleThreadExecutor(String poolName) { |
| return newFixedThreadPool(poolName, 1); |
| } |
| |
| public static class SshdThreadFactory extends AbstractLoggingBean implements ThreadFactory { |
| private final ThreadGroup group; |
| private final AtomicInteger threadNumber = new AtomicInteger(1); |
| private final String namePrefix; |
| |
| public SshdThreadFactory(String name) { |
| SecurityManager s = System.getSecurityManager(); |
| group = (s != null) ? s.getThreadGroup() : Thread.currentThread().getThreadGroup(); |
| String effectiveName = name.replace(' ', '-'); |
| namePrefix = "sshd-" + effectiveName + "-thread-"; |
| } |
| |
| @Override |
| public Thread newThread(final Runnable r) { |
| Thread t; |
| try { |
| // see SSHD-668 |
| t = AccessController.doPrivileged(new PrivilegedExceptionAction<Thread>() { |
| @SuppressWarnings("synthetic-access") |
| @Override |
| public Thread run() { |
| return new Thread(group, r, namePrefix + threadNumber.getAndIncrement(), 0); |
| } |
| }); |
| } catch (PrivilegedActionException e) { |
| Exception err = e.getException(); |
| if (err instanceof RuntimeException) { |
| throw (RuntimeException) err; |
| } else { |
| throw new RuntimeException(err); |
| } |
| } |
| |
| if (!t.isDaemon()) { |
| t.setDaemon(true); |
| } |
| if (t.getPriority() != Thread.NORM_PRIORITY) { |
| t.setPriority(Thread.NORM_PRIORITY); |
| } |
| if (log.isTraceEnabled()) { |
| log.trace("newThread({})[{}] runnable={}", group, t.getName(), r); |
| } |
| return t; |
| } |
| } |
| } |