/* ThreadStartEvent.java -- An event specifying that a new thread
   has started in the virtual machine
   Copyright (C) 2005, 2007 Free Software Foundation

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath 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 for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */


package gnu.classpath.jdwp.event;

import gnu.classpath.jdwp.JdwpConstants;
import gnu.classpath.jdwp.VMIdManager;
import gnu.classpath.jdwp.id.ThreadId;

import java.io.DataOutputStream;
import java.io.IOException;

/**
 * "Notification of a new running thread in the target VM. The new
 * thread can be the result of a call to {@link java.lang.Thread#start} or
 * the result of attaching a new thread to the VM though JNI. The
 * notification is generated by the new thread some time before its
 * execution starts. Because of this timing, it is possible to receive
 * other events for the thread before this event is received. (Notably,
 * Method Entry Events and Method Exit Events might occur during thread
 * initialization. It is also possible for the VirtualMachine AllThreads
 * command to return a thread before its thread start event is received.
 *
 * <p>Note that this event gives no information about the creation of the
 * thread object which may have happened much earlier, depending on the
 * VM being debugged." -- JDWP 1.4.2
 *
 * @author Keith Seitz  (keiths@redhat.com)
 */
public class ThreadStartEvent
  extends Event
{
  private Thread _thread;

  /**
   * Constructs a new ThreadStartEvent object
   *
   * @param thread  the thread ID in which event occurred
   */
  public ThreadStartEvent (Thread thread) {
    super (JdwpConstants.EventKind.THREAD_START);
    _thread = thread;
  }

  /**
   * Returns a specific filtering parameter for this event.
   * Valid types are ThreadId.
   *
   * @param type  the type of parameter desired
   * @returns the desired parameter or <code>null</code>
   */
  public Object getParameter (int type)
  {
    if (type == EVENT_THREAD)
      return _thread;

    return null;
  }

  /**
   * Writes the event to the given stream
   *
   * @param outStream  the output stream to write the event to
   */
  protected void _writeData (DataOutputStream outStream)
    throws IOException
  {
    VMIdManager idm = VMIdManager.getDefault();
    ThreadId tid = (ThreadId) idm.getObjectId (_thread);
    tid.write (outStream);
  }
}