| /* java.lang.ref.PhantomReference |
| Copyright (C) 1999, 2004 Free Software Foundation, Inc. |
| |
| 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 java.lang.ref; |
| |
| /** |
| * A phantom reference is useful, to get notified, when an object got |
| * finalized. You can't access that object though, since it is |
| * finalized. This is the reason, why <code>get()</code> always |
| * returns null. |
| * |
| * @author Jochen Hoenicke |
| */ |
| public class PhantomReference<T> |
| extends Reference<T> |
| { |
| /** |
| * Creates a new phantom reference. |
| * @param referent the object that should be watched. |
| * @param q the queue that should be notified, if the referent was |
| * finalized. This mustn't be <code>null</code>. |
| * @exception NullPointerException if q is null. |
| */ |
| public PhantomReference(T referent, ReferenceQueue<? super T> q) |
| { |
| super(referent, q); |
| } |
| |
| /** |
| * Returns the object, this reference refers to. |
| * @return <code>null</code>, since the refered object may be |
| * finalized and thus not accessible. |
| */ |
| public T get() |
| { |
| return null; |
| } |
| } |