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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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
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package sun.rmi.runtime;

import java.security.AccessController;
import java.security.PrivilegedAction;
import sun.security.util.SecurityConstants;

A PrivilegedAction for creating a new thread conveniently with an
AccessController.doPrivileged construct.
All constructors allow the choice of the Runnable for the new
thread to execute, the name of the new thread (which will be
prefixed with "RMI "), and whether or not it will be a daemon
thread.
The new thread may be created in the system thread group (the root
of the thread group tree) or an internally created non-system
thread group, as specified at construction of this class.
The new thread will have the system class loader as its initial
context class loader (that is, its context class loader will NOT be
inherited from the current thread).
Author:
     Peter Jones/**
 * A PrivilegedAction for creating a new thread conveniently with an
 * AccessController.doPrivileged construct.
 *
 * All constructors allow the choice of the Runnable for the new
 * thread to execute, the name of the new thread (which will be
 * prefixed with "RMI "), and whether or not it will be a daemon
 * thread.
 *
 * The new thread may be created in the system thread group (the root
 * of the thread group tree) or an internally created non-system
 * thread group, as specified at construction of this class.
 *
 * The new thread will have the system class loader as its initial
 * context class loader (that is, its context class loader will NOT be
 * inherited from the current thread).
 *
 * @author      Peter Jones
 **/
public final class NewThreadAction implements PrivilegedAction<Thread> {

    
cached reference to the system (root) thread group /** cached reference to the system (root) thread group */
    static final ThreadGroup systemThreadGroup =
        AccessController.doPrivileged(new PrivilegedAction<ThreadGroup>() {
            public ThreadGroup run() {
                ThreadGroup group = Thread.currentThread().getThreadGroup();
                ThreadGroup parent;
                while ((parent = group.getParent()) != null) {
                    group = parent;
                }
                return group;
            }
        });

    
special child of the system thread group for running tasks that
may execute user code, so that the security policy for threads in
the system thread group will not apply
/**
     * special child of the system thread group for running tasks that
     * may execute user code, so that the security policy for threads in
     * the system thread group will not apply
     */
    static final ThreadGroup userThreadGroup =
        AccessController.doPrivileged(new PrivilegedAction<ThreadGroup>() {
            public ThreadGroup run() {
                return new ThreadGroup(systemThreadGroup, "RMI Runtime");
            }
        });

    private final ThreadGroup group;
    private final Runnable runnable;
    private final String name;
    private final boolean daemon;

    NewThreadAction(ThreadGroup group, Runnable runnable,
                    String name, boolean daemon)
    {
        this.group = group;
        this.runnable = runnable;
        this.name = name;
        this.daemon = daemon;
    }

    
Creates an action that will create a new thread in the
system thread group.
Params:
runnable – the Runnable for the new thread to execute
name – the name of the new thread
daemon – if true, new thread will be a daemon thread;
if false, new thread will not be a daemon thread/**
     * Creates an action that will create a new thread in the
     * system thread group.
     *
     * @param   runnable the Runnable for the new thread to execute
     *
     * @param   name the name of the new thread
     *
     * @param   daemon if true, new thread will be a daemon thread;
     * if false, new thread will not be a daemon thread
     */
    public NewThreadAction(Runnable runnable, String name, boolean daemon) {
        this(systemThreadGroup, runnable, name, daemon);
    }

    
Creates an action that will create a new thread.
Params:
runnable – the Runnable for the new thread to execute
name – the name of the new thread
daemon – if true, new thread will be a daemon thread;
if false, new thread will not be a daemon thread
user – if true, thread will be created in a non-system
thread group; if false, thread will be created in the system
thread group/**
     * Creates an action that will create a new thread.
     *
     * @param   runnable the Runnable for the new thread to execute
     *
     * @param   name the name of the new thread
     *
     * @param   daemon if true, new thread will be a daemon thread;
     * if false, new thread will not be a daemon thread
     *
     * @param   user if true, thread will be created in a non-system
     * thread group; if false, thread will be created in the system
     * thread group
     */
    public NewThreadAction(Runnable runnable, String name, boolean daemon,
                           boolean user)
    {
        this(user ? userThreadGroup : systemThreadGroup,
             runnable, name, daemon);
    }

    public Thread run() {
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
        }
        Thread t = new Thread(group, runnable, "RMI " + name);
        t.setContextClassLoader(ClassLoader.getSystemClassLoader());
        t.setDaemon(daemon);
        return t;
    }
}