Source for gnu.classpath.jdwp.event.Event

   1: /* Event.java -- a base class for all event types
   2:    Copyright (C) 2005, 2007 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:   /**
  58:    * The class of the object in which the event occurred
  59:    */
  60:   public static final int EVENT_CLASS = 1;
  61: 
  62:   /**
  63:    * The thread where the event occurred
  64:    */
  65:   public static final int EVENT_THREAD = 2;
  66: 
  67:   /**
  68:    * The location where an event occurred
  69:    */
  70:   public static final int EVENT_LOCATION = 3;
  71: 
  72:   /**
  73:    * The instance of the class where the event occurred
  74:    */
  75:   public static final int EVENT_INSTANCE = 4;
  76: 
  77:   /**
  78:    * The field acted on by an event
  79:    */
  80:   public static final int EVENT_FIELD = 5;
  81: 
  82:   /**
  83:    * The class of the exception for ExceptionEvent
  84:    */
  85:   public static final int EVENT_EXCEPTION_CLASS = 6;
  86: 
  87:   /**
  88:    * Whether this exception was caught (only valid for ExceptionEvents)
  89:    */
  90:   public static final int EVENT_EXCEPTION_CAUGHT = 7;
  91: 
  92:   // The kind of event represented by this event
  93:   private byte _eventKind;
  94: 
  95:   /**
  96:    * Constructs an <code>Event</code> of the given kind
  97:    *
  98:    * @param kind  the type of event
  99:    */
 100:   public Event (byte kind)
 101:   {
 102:     _eventKind = kind;
 103:   }
 104: 
 105:   /**
 106:    * Returns the event type of this event
 107:    *
 108:    * @returns  the event kind
 109:    */
 110:   public byte getEventKind ()
 111:   {
 112:     return _eventKind;
 113:   }
 114: 
 115:   /**
 116:    * Abstract function used by implementing classes to fill in the
 117:    * event-specific data. Note that request ID is automatically added
 118:    * by this class (since it appears in all event notifications).
 119:    *
 120:    * @param outStream  the stream to which to write data
 121:    */
 122:   protected abstract void _writeData (DataOutputStream outStream)
 123:     throws IOException;
 124: 
 125:   /**
 126:    * Returns a specific filtering parameter for this event. For example,
 127:    * most events may be filtered by thread. Consequently, a call to this
 128:    * method with <code>ThreadId.class</code> should return a
 129:    * <code>Thread</code>.
 130:    *
 131:    * @param type  the type of parameter to return
 132:    * @returns the parameter (not the ID) or <code>null</code> if none is
 133:    *          is defined for this event
 134:    */
 135:   public abstract Object getParameter (int type);
 136: 
 137:   /**
 138:    * Converts the events into to a single JDWP Event.COMPOSITE packet
 139:    *
 140:    * @param dos     the stream to which to write data
 141:    * @param events  the events to package into the packet
 142:    * @param requests the corresponding event requests
 143:    * @param suspendPolicy the suspend policy enforced by the VM
 144:    * @returns a <code>JdwpPacket</code> of the events
 145:    */
 146:   public static JdwpPacket toPacket (DataOutputStream dos,
 147:                                      Event[] events,
 148:                                      EventRequest[] requests,
 149:                                      byte suspendPolicy)
 150:   {
 151:     JdwpPacket pkt;
 152:     try
 153:       {
 154:         dos.writeByte (suspendPolicy);
 155:         dos.writeInt (events.length);
 156:         for (int i = 0; i < events.length; ++i)
 157:           _toData (dos, events[i], requests[i]);
 158: 
 159:         pkt
 160:           = new JdwpCommandPacket (JdwpConstants.CommandSet.Event.CS_VALUE,
 161:                                    JdwpConstants.CommandSet.Event.COMPOSITE);
 162:       }
 163:     catch (IOException ioe)
 164:       {
 165:         pkt = null;
 166:       }
 167: 
 168:     return pkt;
 169:   }
 170: 
 171:   // Helper function for toPacket
 172:   private static void _toData (DataOutputStream dos, Event event,
 173:                                EventRequest request)
 174:     throws IOException
 175:   {
 176:     dos.writeByte (event._eventKind);
 177:     dos.writeInt (request.getId ());
 178:     event._writeData (dos);
 179:   }
 180: }