thread.java

linux下编程用 编译软件

      }
    else if (sm != null)
	sm.checkAccess(group);

    this.group = group;
    // Use toString hack to detect null.
    this.name = name.toString();
    this.runnable = target;
    this.stacksize = size;

    priority = current.priority;
    daemon = current.daemon;
    contextClassLoader = current.contextClassLoader;

    group.addThread(this);
    InheritableThreadLocal.newChildThread(this);
  }

  /**
   * Used by the VM to create thread objects for threads started outside
   * of Java. Note: caller is responsible for adding the thread to
   * a group and InheritableThreadLocal.
   *
   * @param vmThread the native thread
   * @param name the thread name or null to use the default naming scheme
   * @param priority current priority
   * @param daemon is the thread a background thread?
   */
  Thread(VMThread vmThread, String name, int priority, boolean daemon)
  {
    this.vmThread = vmThread;
    this.runnable = null;
    if (name == null)
	name = "Thread-" + ++numAnonymousThreadsCreated;
    this.name = name;
    this.priority = priority;
    this.daemon = daemon;
    this.contextClassLoader = ClassLoader.getSystemClassLoader();
  }

  /**
   * Get the number of active threads in the current Thread's ThreadGroup.
   * This implementation calls
   * <code>currentThread().getThreadGroup().activeCount()</code>.
   *
   * @return the number of active threads in the current ThreadGroup
   * @see ThreadGroup#activeCount()
   */
  public static int activeCount()
  {
    return currentThread().group.activeCount();
  }

  /**
   * Check whether the current Thread is allowed to modify this Thread. This
   * passes the check on to <code>SecurityManager.checkAccess(this)</code>.
   *
   * @throws SecurityException if the current Thread cannot modify this Thread
   * @see SecurityManager#checkAccess(Thread)
   */
  public final void checkAccess()
  {
    // Bypass System.getSecurityManager, for bootstrap efficiency.
    SecurityManager sm = SecurityManager.current;
    if (sm != null)
      sm.checkAccess(this);
  }

  /**
   * Count the number of stack frames in this Thread.  The Thread in question
   * must be suspended when this occurs.
   *
   * @return the number of stack frames in this Thread
   * @throws IllegalThreadStateException if this Thread is not suspended
   * @deprecated pointless, since suspend is deprecated
   */
  public int countStackFrames()
  {
    VMThread t = vmThread;
    if (t == null || group == null)
	throw new IllegalThreadStateException();

    return t.countStackFrames();
  }

  /**
   * Get the currently executing Thread. In the situation that the
   * currently running thread was created by native code and doesn't
   * have an associated Thread object yet, a new Thread object is
   * constructed and associated with the native thread.
   *
   * @return the currently executing Thread
   */
  public static Thread currentThread()
  {
    return VMThread.currentThread();
  }

  /**
   * Originally intended to destroy this thread, this method was never
   * implemented by Sun, and is hence a no-op.
   */
  public void destroy()
  {
    throw new NoSuchMethodError();
  }
  
  /**
   * Print a stack trace of the current thread to stderr using the same
   * format as Throwable's printStackTrace() method.
   *
   * @see Throwable#printStackTrace()
   */
  public static void dumpStack()
  {
    new Throwable().printStackTrace();
  }

  /**
   * Copy every active thread in the current Thread's ThreadGroup into the
   * array. Extra threads are silently ignored. This implementation calls
   * <code>getThreadGroup().enumerate(array)</code>, which may have a
   * security check, <code>checkAccess(group)</code>.
   *
   * @param array the array to place the Threads into
   * @return the number of Threads placed into the array
   * @throws NullPointerException if array is null
   * @throws SecurityException if you cannot access the ThreadGroup
   * @see ThreadGroup#enumerate(Thread[])
   * @see #activeCount()
   * @see SecurityManager#checkAccess(ThreadGroup)
   */
  public static int enumerate(Thread[] array)
  {
    return currentThread().group.enumerate(array);
  }
  
  /**
   * Get this Thread's name.
   *
   * @return this Thread's name
   */
  public final String getName()
  {
    VMThread t = vmThread;
    return t == null ? name : t.getName();
  }

  /**
   * Get this Thread's priority.
   *
   * @return the Thread's priority
   */
  public final synchronized int getPriority()
  {
    VMThread t = vmThread;
    return t == null ? priority : t.getPriority();
  }

  /**
   * Get the ThreadGroup this Thread belongs to. If the thread has died, this
   * returns null.
   *
   * @return this Thread's ThreadGroup
   */
  public final ThreadGroup getThreadGroup()
  {
    return group;
  }

  /**
   * Checks whether the current thread holds the monitor on a given object.
   * This allows you to do <code>assert Thread.holdsLock(obj)</code>.
   *
   * @param obj the object to test lock ownership on.
   * @return true if the current thread is currently synchronized on obj
   * @throws NullPointerException if obj is null
   * @since 1.4
   */
  public static boolean holdsLock(Object obj)
  {
    return VMThread.holdsLock(obj);
  }

  /**
   * Interrupt this Thread. First, there is a security check,
   * <code>checkAccess</code>. Then, depending on the current state of the
   * thread, various actions take place:
   *
   * <p>If the thread is waiting because of {@link #wait()},
   * {@link #sleep(long)}, or {@link #join()}, its <i>interrupt status</i>
   * will be cleared, and an InterruptedException will be thrown. Notice that
   * this case is only possible if an external thread called interrupt().
   *
   * <p>If the thread is blocked in an interruptible I/O operation, in
   * {@link java.nio.channels.InterruptibleChannel}, the <i>interrupt
   * status</i> will be set, and ClosedByInterruptException will be thrown.
   *
   * <p>If the thread is blocked on a {@link java.nio.channels.Selector}, the
   * <i>interrupt status</i> will be set, and the selection will return, with
   * a possible non-zero value, as though by the wakeup() method.
   *
   * <p>Otherwise, the interrupt status will be set.
   *
   * @throws SecurityException if you cannot modify this Thread
   */
  public synchronized void interrupt()
  {
    checkAccess();
    VMThread t = vmThread;
    if (t != null)
	t.interrupt();
  }

  /**
   * Determine whether the current Thread has been interrupted, and clear
   * the <i>interrupted status</i> in the process.
   *
   * @return whether the current Thread has been interrupted
   * @see #isInterrupted()
   */
  public static boolean interrupted()
  {
    return VMThread.interrupted();
  }

  /**
   * Determine whether the given Thread has been interrupted, but leave
   * the <i>interrupted status</i> alone in the process.
   *
   * @return whether the Thread has been interrupted
   * @see #interrupted()
   */
  public boolean isInterrupted()
  {
    VMThread t = vmThread;
    return t != null && t.isInterrupted();
  }

  /**
   * Determine whether this Thread is alive. A thread which is alive has
   * started and not yet died.
   *
   * @return whether this Thread is alive
   */
  public final boolean isAlive()
  {
    return vmThread != null && group != null;
  }

  /**
   * Tell whether this is a daemon Thread or not.
   *
   * @return whether this is a daemon Thread or not
   * @see #setDaemon(boolean)
   */
  public final boolean isDaemon()
  {
    VMThread t = vmThread;
    return t == null ? daemon : t.isDaemon();
  }

  /**
   * Wait forever for the Thread in question to die.
   *
   * @throws InterruptedException if the Thread is interrupted; it's
   *         <i>interrupted status</i> will be cleared
   */
  public final void join() throws InterruptedException
  {
    join(0, 0);
  }

  /**
   * Wait the specified amount of time for the Thread in question to die.
   *
   * @param ms the number of milliseconds to wait, or 0 for forever
   * @throws InterruptedException if the Thread is interrupted; it's
   *         <i>interrupted status</i> will be cleared
   */
  public final void join(long ms) throws InterruptedException
  {
    join(ms, 0);
  }

  /**
   * Wait the specified amount of time for the Thread in question to die.
   *
   * <p>Note that 1,000,000 nanoseconds == 1 millisecond, but most VMs do
   * not offer that fine a grain of timing resolution. Besides, there is
   * no guarantee that this thread can start up immediately when time expires,
   * because some other thread may be active.  So don't expect real-time
   * performance.
   *
   * @param ms the number of milliseconds to wait, or 0 for forever
   * @param ns the number of extra nanoseconds to sleep (0-999999)
   * @throws InterruptedException if the Thread is interrupted; it's
   *         <i>interrupted status</i> will be cleared
   * @throws IllegalArgumentException if ns is invalid
   */
  public final void join(long ms, int ns) throws InterruptedException
  {
    if(ms < 0 || ns < 0 || ns > 999999)
	throw new IllegalArgumentException();

    VMThread t = vmThread;
    if(t != null)
        t.join(ms, ns);
  }

  /**
   * Resume this Thread.  If the thread is not suspended, this method does
   * nothing. To mirror suspend(), there may be a security check:
   * <code>checkAccess</code>.
   *
   * @throws SecurityException if you cannot resume the Thread
   * @see #checkAccess()
   * @see #suspend()
   * @deprecated pointless, since suspend is deprecated
   */
  public final synchronized void resume()
  {
    checkAccess();
    VMThread t = vmThread;
    if (t != null)
	t.resume();
  }
  
  /**
   * The method of Thread that will be run if there is no Runnable object
   * associated with the Thread. Thread's implementation does nothing at all.
   *
   * @see #start()
   * @see #Thread(ThreadGroup, Runnable, String)
   */