Source for gnu.classpath.jdwp.event.Event

   1: /* Event.java -- a base class for all event types
   2:    Copyright (C) 2005 Free Software Foundation
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: terms of your choice, provided that you also meet, for each linked
  32: independent module, the terms and conditions of the license of that
  33: module.  An independent module is a module which is not derived from
  34: or based on this library.  If you modify this library, you may extend
  35: this exception to your version of the library, but you are not
  36: obligated to do so.  If you do not wish to do so, delete this
  37: exception statement from your version. */
  38: 
  39: 
  40: package gnu.classpath.jdwp.event;
  41: 
  42: import gnu.classpath.jdwp.JdwpConstants;
  43: import gnu.classpath.jdwp.transport.JdwpCommandPacket;
  44: import gnu.classpath.jdwp.transport.JdwpPacket;
  45: 
  46: import java.io.DataOutputStream;
  47: import java.io.IOException;
  48: 
  49: /**
  50:  * This class is a base class for all VM->debugger event
  51:  * notifications.
  52:  *
  53:  * @author Keith Seitz  (keiths@redhat.com)
  54:  */
  55: public abstract class Event
  56: {
  57:   // The kind of event represented by this event
  58:   private byte _eventKind;
  59: 
  60:   /**
  61:    * Constructs an <code>Event</code> of the given kind
  62:    *
  63:    * @param kind  the type of event
  64:    */
  65:   public Event (byte kind)
  66:   {
  67:     _eventKind = kind;
  68:   }
  69: 
  70:   /**
  71:    * Returns the event type of this event
  72:    *
  73:    * @returns  the event kind
  74:    */
  75:   public byte getEventKind ()
  76:   {
  77:     return _eventKind;
  78:   }
  79: 
  80:   /**
  81:    * Abstract function used by implementing classes to fill in the
  82:    * event-specific data. Note that request ID is automatically added
  83:    * by this class (since it appears in all event notifications).
  84:    *
  85:    * @param outStream  the stream to which to write data
  86:    */
  87:   protected abstract void _writeData (DataOutputStream outStream)
  88:     throws IOException;
  89: 
  90:   /**
  91:    * Returns a specific filtering parameter for this event. For example,
  92:    * most events may be filtered by thread. Consequently, a call to this
  93:    * method with <code>ThreadId.class</code> should return a
  94:    * <code>Thread</code>.
  95:    *
  96:    * @param type  the type of parameter to return
  97:    * @returns the parameter (not the ID) or <code>null</code> if none is
  98:    *          is defined for this event
  99:    */
 100:   public abstract Object getParameter (Class type);
 101: 
 102:   /**
 103:    * Converts this event into to a JDWP packet
 104:    *
 105:    * @param dos     the stream to which to write data
 106:    * @param request the request the wanted this notification
 107:    * @returns a <code>JdwpPacket</code> of the events
 108:    */
 109:   public JdwpPacket toPacket (DataOutputStream dos, EventRequest request)
 110:   {
 111:     JdwpPacket pkt;
 112:     try
 113:       {
 114:     dos.writeByte (request.getSuspendPolicy ());
 115:     dos.writeInt (1);
 116:     dos.writeByte (_eventKind);
 117:     dos.writeInt (request.getId ());
 118:     _writeData (dos);
 119: 
 120:     pkt = new JdwpCommandPacket (JdwpConstants.CommandSet.Event.CS_VALUE,
 121:                      JdwpConstants.CommandSet.Event.COMPOSITE);
 122:       }
 123:     catch (IOException ioe)
 124:       {
 125:     pkt = null;
 126:       }
 127: 
 128:     return pkt;
 129:   }
 130: }