/*
*
*
* Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program 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 version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package java.lang.ref;
/**
* This class provides support for weak references. Weak references
* are most often used to implement canonicalizing mappings.
*
* Suppose that the garbage collector determines at a certain
* point in time that an object is weakly reachable. At that
* time it will atomically clear all the weak references to
* that object and all weak references to any other weakly-
* reachable objects from which that object is reachable
* through a chain of strong and weak references.
*
* @version 12/19/01 (CLDC 1.1)
* @since JDK1.2, CLDC 1.1
*/
/*
* Implementation note: It is generally recommended that
* you don't subclass the WeakReference class. The garbage
* collector treats weak references specially, and the
* subclasses of class WeakReference might not be handled
* correctly by the garbage collector.
*/
public class WeakReference extends Reference {
private int referent_index;
/**
* Returns this reference object's referent. If this reference object has
* been cleared, either by the program or by the garbage collector, then
* this method returns <code>null</code>.
*
* @return The object to which this reference refers, or
* <code>null</code> if this reference object has been cleared
*/
public native Object get();
/**
* Clears this reference object.
*/
public native void clear();
/**
* Creates a new weak reference that refers to the given object.
*/
public WeakReference(Object referent) {
super(referent);
initializeWeakReference(referent);
}
private native void initializeWeakReference(Object referent);
private native void finalize();
}
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