| /* |
| * Copyright (c) 2005, 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.rmi.runtime; |
| |
| import java.security.AccessController; |
| import java.security.Permission; |
| import java.security.PrivilegedAction; |
| import java.util.concurrent.ScheduledThreadPoolExecutor; |
| import java.util.concurrent.ThreadFactory; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.atomic.AtomicInteger; |
| import java.util.logging.Level; |
| |
| /** |
| * RMI runtime implementation utilities. |
| * |
| * There is a single instance of this class, which can be obtained |
| * with a GetInstanceAction. Getting the instance requires |
| * RuntimePermission("sun.rmi.runtime.RuntimeUtil.getInstance") |
| * because the public methods of this class expose security-sensitive |
| * capabilities. |
| * |
| * @author Peter Jones |
| **/ |
| public final class RuntimeUtil { |
| |
| /** runtime package log */ |
| private static final Log runtimeLog = |
| Log.getLog("sun.rmi.runtime", null, false); |
| |
| /** number of scheduler threads */ |
| private static final int schedulerThreads = // default 1 |
| AccessController.doPrivileged((PrivilegedAction<Integer>) () -> |
| Integer.getInteger("sun.rmi.runtime.schedulerThreads", 1)); |
| |
| /** permission required to get instance */ |
| private static final Permission GET_INSTANCE_PERMISSION = |
| new RuntimePermission("sun.rmi.runtime.RuntimeUtil.getInstance"); |
| |
| /** the singleton instance of this class */ |
| private static final RuntimeUtil instance = new RuntimeUtil(); |
| |
| /** thread pool for scheduling delayed tasks */ |
| private final ScheduledThreadPoolExecutor scheduler; |
| |
| private RuntimeUtil() { |
| scheduler = new ScheduledThreadPoolExecutor( |
| schedulerThreads, |
| new ThreadFactory() { |
| private final AtomicInteger count = new AtomicInteger(0); |
| public Thread newThread(Runnable runnable) { |
| try { |
| return AccessController.doPrivileged( |
| new NewThreadAction(runnable, |
| "Scheduler(" + count.getAndIncrement() + ")", |
| true)); |
| } catch (Throwable t) { |
| runtimeLog.log(Level.WARNING, |
| "scheduler thread factory throws", t); |
| return null; |
| } |
| } |
| }); |
| /* |
| * We would like to allow the scheduler's threads to terminate |
| * if possible, but a bug in DelayQueue.poll can cause code |
| * like this to result in a busy loop: |
| */ |
| // stpe.setKeepAliveTime(10, TimeUnit.MINUTES); |
| // stpe.allowCoreThreadTimeOut(true); |
| } |
| |
| /** |
| * A PrivilegedAction for getting the RuntimeUtil instance. |
| **/ |
| public static class GetInstanceAction |
| implements PrivilegedAction<RuntimeUtil> |
| { |
| /** |
| * Creates an action that returns the RuntimeUtil instance. |
| **/ |
| public GetInstanceAction() { |
| } |
| |
| public RuntimeUtil run() { |
| return getInstance(); |
| } |
| } |
| |
| private static RuntimeUtil getInstance() { |
| SecurityManager sm = System.getSecurityManager(); |
| if (sm != null) { |
| sm.checkPermission(GET_INSTANCE_PERMISSION); |
| } |
| return instance; |
| } |
| |
| /** |
| * Returns the shared thread pool for scheduling delayed tasks. |
| * |
| * Note that the returned pool has limited concurrency, so |
| * submitted tasks should be short-lived and should not block. |
| **/ |
| public ScheduledThreadPoolExecutor getScheduler() { |
| return scheduler; |
| } |
| } |