327 lines
7.5 KiB
Java
327 lines
7.5 KiB
Java
// Thread.java - Thread class.
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/* Copyright (C) 1998, 1999, 2000 Free Software Foundation
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This file is part of libgcj.
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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package java.lang;
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/**
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* @author Tom Tromey <tromey@cygnus.com>
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* @date August 24, 1998
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*/
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/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
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* "The Java Language Specification", ISBN 0-201-63451-1
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* plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
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* Status: Complete to version 1.1, with caveats
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* Known problems:
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* No attempt was made to implement suspend/resume
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* (this could be done in some cases)
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* Various methods which assume a VM are likewise unimplemented
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* We do implement stop() even though it is deprecated.
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*/
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public class Thread implements Runnable
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{
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public final static int MAX_PRIORITY = 10;
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public final static int MIN_PRIORITY = 1;
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public final static int NORM_PRIORITY = 5;
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public static int activeCount ()
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{
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return currentThread().getThreadGroup().activeCount();
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}
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public final void checkAccess ()
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{
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SecurityManager s = System.getSecurityManager();
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if (s != null)
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s.checkAccess(this);
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}
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public native int countStackFrames ();
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public static native Thread currentThread ();
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public native void destroy ();
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public static void dumpStack ()
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{
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(new Exception ("Stack trace")).printStackTrace ();
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}
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public static int enumerate (Thread[] threads)
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{
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return currentThread().group.enumerate(threads);
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}
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public final String getName ()
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{
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return name;
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}
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public final int getPriority ()
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{
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return priority;
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}
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public final ThreadGroup getThreadGroup ()
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{
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return group;
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}
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public native void interrupt ();
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public static boolean interrupted ()
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{
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return currentThread().isInterrupted (true);
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}
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// Check the threads interrupted status. Note that this does not clear the
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// thread's interrupted status (per JDK 1.2 online API documentation).
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public boolean isInterrupted ()
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{
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return interrupt_flag;
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}
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public final boolean isAlive ()
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{
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return alive_flag;
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}
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public final boolean isDaemon ()
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{
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return daemon_flag;
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}
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public final void join () throws InterruptedException
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{
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join (0, 0);
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}
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public final void join (long timeout) throws InterruptedException
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{
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join (timeout, 0);
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}
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public final native void join (long timeout, int nanos)
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throws InterruptedException;
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public final native void resume ();
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// This method exists only to avoid a warning from the C++ compiler.
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private static final native void run_ (Object obj);
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private final native void finish_ ();
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// Check the thread's interrupted status. If clear_flag is true, the
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// thread's interrupted status is also cleared.
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private boolean isInterrupted (boolean clear_flag)
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{
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boolean r = interrupt_flag;
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if (clear_flag && r)
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{
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// Only clear the flag if we saw it as set. Otherwise this could
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// potentially cause us to miss an interrupt in a race condition,
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// because this method is not synchronized.
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interrupt_flag = false;
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}
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return r;
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}
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public void run ()
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{
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if (runnable != null)
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runnable.run();
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}
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public final void setDaemon (boolean status)
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{
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checkAccess ();
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if (isAlive ())
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throw new IllegalThreadStateException ();
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daemon_flag = status;
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}
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public synchronized ClassLoader getContextClassLoader()
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{
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if (context_class_loader == null)
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context_class_loader = ClassLoader.getSystemClassLoader ();
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SecurityManager s = System.getSecurityManager();
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// FIXME: we can't currently find the caller's class loader.
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ClassLoader callers = null;
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if (s != null && callers != null)
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{
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// See if the caller's class loader is the same as or an
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// ancestor of this thread's class loader.
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while (callers != null && callers != context_class_loader)
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{
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// FIXME: should use some internal version of getParent
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// that avoids security checks.
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callers = callers.getParent ();
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}
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if (callers != context_class_loader)
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s.checkPermission (new RuntimePermission ("getClassLoader"));
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}
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return context_class_loader;
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}
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public synchronized void setContextClassLoader(ClassLoader cl)
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{
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SecurityManager s = System.getSecurityManager ();
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if (s != null)
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s.checkPermission (new RuntimePermission ("setContextClassLoader"));
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context_class_loader = cl;
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}
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public final void setName (String n)
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{
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checkAccess ();
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// The Class Libraries book says ``threadName cannot be null''. I
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// take this to mean NullPointerException.
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if (n == null)
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throw new NullPointerException ();
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name = n;
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}
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public final native void setPriority (int newPriority);
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public static void sleep (long timeout) throws InterruptedException
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{
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sleep (timeout, 0);
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}
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public static native void sleep (long timeout, int nanos)
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throws InterruptedException;
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public synchronized native void start ();
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public final void stop ()
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{
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// Argument doesn't matter, because this is no longer
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// supported.
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stop (null);
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}
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public final synchronized native void stop (Throwable e);
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public final native void suspend ();
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private final native void initialize_native ();
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private final synchronized static String gen_name ()
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{
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String n;
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n = "Thread-" + nextThreadNumber;
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++nextThreadNumber;
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return n;
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}
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public Thread (ThreadGroup g, Runnable r, String n)
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{
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Thread current = currentThread ();
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if (g == null)
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{
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// If CURRENT is null, then we are bootstrapping the first thread.
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// Use ThreadGroup.root, the main threadgroup.
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if (current == null)
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group = ThreadGroup.root;
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else
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group = current.getThreadGroup();
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}
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else
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group = g;
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group.checkAccess();
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// The Class Libraries book says ``threadName cannot be null''. I
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// take this to mean NullPointerException.
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if (n == null)
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throw new NullPointerException ();
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name = n;
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group.addThread(this);
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runnable = r;
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data = null;
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interrupt_flag = false;
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alive_flag = false;
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startable_flag = true;
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if (current != null)
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{
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daemon_flag = current.isDaemon();
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int gmax = group.getMaxPriority();
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int pri = current.getPriority();
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priority = (gmax < pri ? gmax : pri);
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context_class_loader = current.context_class_loader;
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}
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else
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{
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daemon_flag = false;
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priority = NORM_PRIORITY;
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}
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initialize_native ();
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}
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public Thread ()
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{
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this (null, null, gen_name ());
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}
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public Thread (Runnable r)
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{
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this (null, r, gen_name ());
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}
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public Thread (String n)
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{
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this (null, null, n);
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}
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public Thread (ThreadGroup g, Runnable r)
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{
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this (g, r, gen_name ());
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}
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public Thread (ThreadGroup g, String n)
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{
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this (g, null, n);
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}
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public Thread (Runnable r, String n)
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{
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this (null, r, n);
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}
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public String toString ()
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{
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return "Thread[" + name + "," + priority + "," +
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(group == null ? "" : group.getName()) + "]";
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}
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public static native void yield ();
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// Private data.
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private ThreadGroup group;
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private String name;
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private Runnable runnable;
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private int priority;
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private boolean daemon_flag;
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boolean interrupt_flag;
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private boolean alive_flag;
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private boolean startable_flag;
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private ClassLoader context_class_loader;
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// Our native data.
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private Object data;
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// Next thread number to assign.
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private static int nextThreadNumber = 0;
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}
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