| /* NullObjectId.java -- special objectId for null values |
| Copyright (C) 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 |
| 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.id; |
| |
| import gnu.classpath.jdwp.exception.InvalidObjectException; |
| import gnu.classpath.jdwp.util.NullObject; |
| |
| import java.lang.ref.SoftReference; |
| |
| /** |
| * This is a special case of an ObjectId. When a varaible slot contains |
| * null as its value, this is a valid value despite the fact that it does |
| * not reference an object. To represent this, this will always be the id |
| * of the NullObject (0). |
| * |
| * @author Kyle Galloway <kgallowa@redhat.com> |
| */ |
| public class NullObjectId |
| extends ObjectId |
| { |
| /** |
| * The object class that this id represents |
| */ |
| public static final Class typeClass = NullObject.class; |
| |
| /** |
| * Constructs a new <code>NullObjectId</code> |
| */ |
| public NullObjectId() |
| { |
| super(); |
| setId((long) 0); |
| _reference = new SoftReference<NullObject>(new NullObject()); |
| try |
| { |
| disableCollection(); |
| } |
| catch(InvalidObjectException ex) |
| { |
| //This will not happen |
| } |
| } |
| |
| } |