J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2005 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.rmi.runtime; |
| 27 | |
| 28 | import java.security.AccessController; |
| 29 | import java.security.PrivilegedAction; |
| 30 | import sun.security.util.SecurityConstants; |
| 31 | |
| 32 | /** |
| 33 | * A PrivilegedAction for creating a new thread conveniently with an |
| 34 | * AccessController.doPrivileged construct. |
| 35 | * |
| 36 | * All constructors allow the choice of the Runnable for the new |
| 37 | * thread to execute, the name of the new thread (which will be |
| 38 | * prefixed with "RMI "), and whether or not it will be a daemon |
| 39 | * thread. |
| 40 | * |
| 41 | * The new thread may be created in the system thread group (the root |
| 42 | * of the thread group tree) or an internally created non-system |
| 43 | * thread group, as specified at construction of this class. |
| 44 | * |
| 45 | * The new thread will have the system class loader as its initial |
| 46 | * context class loader (that is, its context class loader will NOT be |
| 47 | * inherited from the current thread). |
| 48 | * |
| 49 | * @author Peter Jones |
| 50 | **/ |
| 51 | public final class NewThreadAction implements PrivilegedAction<Thread> { |
| 52 | |
| 53 | /** cached reference to the system (root) thread group */ |
| 54 | static final ThreadGroup systemThreadGroup = |
| 55 | AccessController.doPrivileged(new PrivilegedAction<ThreadGroup>() { |
| 56 | public ThreadGroup run() { |
| 57 | ThreadGroup group = Thread.currentThread().getThreadGroup(); |
| 58 | ThreadGroup parent; |
| 59 | while ((parent = group.getParent()) != null) { |
| 60 | group = parent; |
| 61 | } |
| 62 | return group; |
| 63 | } |
| 64 | }); |
| 65 | |
| 66 | /** |
| 67 | * special child of the system thread group for running tasks that |
| 68 | * may execute user code, so that the security policy for threads in |
| 69 | * the system thread group will not apply |
| 70 | */ |
| 71 | static final ThreadGroup userThreadGroup = |
| 72 | AccessController.doPrivileged(new PrivilegedAction<ThreadGroup>() { |
| 73 | public ThreadGroup run() { |
| 74 | return new ThreadGroup(systemThreadGroup, "RMI Runtime"); |
| 75 | } |
| 76 | }); |
| 77 | |
| 78 | private final ThreadGroup group; |
| 79 | private final Runnable runnable; |
| 80 | private final String name; |
| 81 | private final boolean daemon; |
| 82 | |
| 83 | NewThreadAction(ThreadGroup group, Runnable runnable, |
| 84 | String name, boolean daemon) |
| 85 | { |
| 86 | this.group = group; |
| 87 | this.runnable = runnable; |
| 88 | this.name = name; |
| 89 | this.daemon = daemon; |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * Creates an action that will create a new thread in the |
| 94 | * system thread group. |
| 95 | * |
| 96 | * @param runnable the Runnable for the new thread to execute |
| 97 | * |
| 98 | * @param name the name of the new thread |
| 99 | * |
| 100 | * @param daemon if true, new thread will be a daemon thread; |
| 101 | * if false, new thread will not be a daemon thread |
| 102 | */ |
| 103 | public NewThreadAction(Runnable runnable, String name, boolean daemon) { |
| 104 | this(systemThreadGroup, runnable, name, daemon); |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * Creates an action that will create a new thread. |
| 109 | * |
| 110 | * @param runnable the Runnable for the new thread to execute |
| 111 | * |
| 112 | * @param name the name of the new thread |
| 113 | * |
| 114 | * @param daemon if true, new thread will be a daemon thread; |
| 115 | * if false, new thread will not be a daemon thread |
| 116 | * |
| 117 | * @param user if true, thread will be created in a non-system |
| 118 | * thread group; if false, thread will be created in the system |
| 119 | * thread group |
| 120 | */ |
| 121 | public NewThreadAction(Runnable runnable, String name, boolean daemon, |
| 122 | boolean user) |
| 123 | { |
| 124 | this(user ? userThreadGroup : systemThreadGroup, |
| 125 | runnable, name, daemon); |
| 126 | } |
| 127 | |
| 128 | public Thread run() { |
| 129 | SecurityManager sm = System.getSecurityManager(); |
| 130 | if (sm != null) { |
| 131 | sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); |
| 132 | } |
| 133 | Thread t = new Thread(group, runnable, "RMI " + name); |
| 134 | t.setContextClassLoader(ClassLoader.getSystemClassLoader()); |
| 135 | t.setDaemon(daemon); |
| 136 | return t; |
| 137 | } |
| 138 | } |