69 lines
2.3 KiB
Java
69 lines
2.3 KiB
Java
/* java.lang.ref.WeakReference
|
|
Copyright (C) 1999 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., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA.
|
|
|
|
As a special exception, if you link this library with other files to
|
|
produce an executable, this library does not by itself cause the
|
|
resulting executable to be covered by the GNU General Public License.
|
|
This exception does not however invalidate any other reasons why the
|
|
executable file might be covered by the GNU General Public License. */
|
|
|
|
|
|
package java.lang.ref;
|
|
|
|
/**
|
|
* A weak reference will be cleared, if the object is only weakly
|
|
* reachable. It is useful for lookup tables, where you aren't
|
|
* interested in an entry, if the key isn't reachable anymore.
|
|
* <code>WeakHashtable</code> is a complete implementation of such a
|
|
* table. <br>
|
|
*
|
|
* It is also useful to make objects unique: You create a set of weak
|
|
* references to those objects, and when you create a new object you
|
|
* look in this set, if the object already exists and return it. If
|
|
* an object is not referenced anymore, the reference will
|
|
* automatically cleared, and you may remove it from the set. <br>
|
|
*
|
|
* @author Jochen Hoenicke
|
|
* @see java.util.WeakHashtable
|
|
*/
|
|
public class WeakReference
|
|
extends Reference
|
|
{
|
|
/**
|
|
* Create a new weak reference, that is not registered to any queue.
|
|
* @param referent the object we refer to.
|
|
*/
|
|
public WeakReference(Object referent)
|
|
{
|
|
super(referent);
|
|
}
|
|
|
|
/**
|
|
* Create a new weak reference.
|
|
* @param referent the object we refer to.
|
|
* @param q the reference queue to register on.
|
|
* @exception NullPointerException if q is null.
|
|
*/
|
|
public WeakReference(Object referent, ReferenceQueue q)
|
|
{
|
|
super(referent, q);
|
|
}
|
|
}
|