/* Event.java -- a base class for all event types   Copyright (C) 2005 Free Software FoundationThis file is part of GNU Classpath.GNU Classpath is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe 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, butWITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNUGeneral Public License for more details.You should have received a copy of the GNU General Public Licensealong with GNU Classpath; see the file COPYING.  If not, write to theFree Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA02110-1301 USA.Linking this library statically or dynamically with other modules ismaking a combined work based on this library.  Thus, the terms andconditions of the GNU General Public License cover the wholecombination.As a special exception, the copyright holders of this library give youpermission to link this library with independent modules to produce anexecutable, regardless of the license terms of these independentmodules, and to copy and distribute the resulting executable underterms of your choice, provided that you also meet, for each linkedterms of your choice, provided that you also meet, for each linkedindependent module, the terms and conditions of the license of thatmodule.  An independent module is a module which is not derived fromor based on this library.  If you modify this library, you may extendthis exception to your version of the library, but you are notobligated to do so.  If you do not wish to do so, delete thisexception statement from your version. */package gnu.classpath.jdwp.event;import gnu.classpath.jdwp.JdwpConstants;import gnu.classpath.jdwp.transport.JdwpCommandPacket;import gnu.classpath.jdwp.transport.JdwpPacket;import java.io.DataOutputStream;import java.io.IOException;/** * This class is a base class for all VM->debugger event * notifications. * * @author Keith Seitz  (keiths@redhat.com) */public abstract class Event{  // The kind of event represented by this event  private byte _eventKind;  /**   * Constructs an <code>Event</code> of the given kind   *   * @param kind  the type of event   */  public Event (byte kind)  {    _eventKind = kind;  }  /**   * Returns the event type of this event   *   * @returns  the event kind   */  public byte getEventKind ()  {    return _eventKind;  }  /**   * Abstract function used by implementing classes to fill in the   * event-specific data. Note that request ID is automatically added   * by this class (since it appears in all event notifications).   *   * @param outStream  the stream to which to write data   */  protected abstract void _writeData (DataOutputStream outStream)    throws IOException;  /**   * Returns a specific filtering parameter for this event. For example,   * most events may be filtered by thread. Consequently, a call to this   * method with <code>ThreadId.class</code> should return a   * <code>Thread</code>.   *   * @param type  the type of parameter to return   * @returns the parameter (not the ID) or <code>null</code> if none is   *          is defined for this event   */  public abstract Object getParameter (Class type);  /**   * Converts this event into to a JDWP packet   *   * @param dos     the stream to which to write data   * @param request the request the wanted this notification   * @returns a <code>JdwpPacket</code> of the events   */  public JdwpPacket toPacket (DataOutputStream dos, EventRequest request)  {    JdwpPacket pkt;    try      {	dos.writeByte (request.getSuspendPolicy ());	dos.writeInt (1);	dos.writeByte (_eventKind);	dos.writeInt (request.getId ());	_writeData (dos);	pkt = new JdwpCommandPacket (JdwpConstants.CommandSet.Event.CS_VALUE,				     JdwpConstants.CommandSet.Event.COMPOSITE);      }    catch (IOException ioe)      {	pkt = null;      }    return pkt;  }}