jaroslav@601: /*
jaroslav@601:  * Copyright (c) 1997, 2003, Oracle and/or its affiliates. All rights reserved.
jaroslav@601:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
jaroslav@601:  *
jaroslav@601:  * This code is free software; you can redistribute it and/or modify it
jaroslav@601:  * under the terms of the GNU General Public License version 2 only, as
jaroslav@601:  * published by the Free Software Foundation.  Oracle designates this
jaroslav@601:  * particular file as subject to the "Classpath" exception as provided
jaroslav@601:  * by Oracle in the LICENSE file that accompanied this code.
jaroslav@601:  *
jaroslav@601:  * This code is distributed in the hope that it will be useful, but WITHOUT
jaroslav@601:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
jaroslav@601:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
jaroslav@601:  * version 2 for more details (a copy is included in the LICENSE file that
jaroslav@601:  * accompanied this code).
jaroslav@601:  *
jaroslav@601:  * You should have received a copy of the GNU General Public License version
jaroslav@601:  * 2 along with this work; if not, write to the Free Software Foundation,
jaroslav@601:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
jaroslav@601:  *
jaroslav@601:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
jaroslav@601:  * or visit www.oracle.com if you need additional information or have any
jaroslav@601:  * questions.
jaroslav@601:  */
jaroslav@601: 
jaroslav@601: package java.lang.ref;
jaroslav@601: 
jaroslav@601: 
jaroslav@601: /**
jaroslav@601:  * Weak reference objects, which do not prevent their referents from being
jaroslav@601:  * made finalizable, finalized, and then reclaimed.  Weak references are most
jaroslav@601:  * often used to implement canonicalizing mappings.
jaroslav@601:  *
jaroslav@601:  * <p> Suppose that the garbage collector determines at a certain point in time
jaroslav@601:  * that an object is <a href="package-summary.html#reachability">weakly
jaroslav@601:  * reachable</a>.  At that time it will atomically clear all weak references to
jaroslav@601:  * that object and all weak references to any other weakly-reachable objects
jaroslav@601:  * from which that object is reachable through a chain of strong and soft
jaroslav@601:  * references.  At the same time it will declare all of the formerly
jaroslav@601:  * weakly-reachable objects to be finalizable.  At the same time or at some
jaroslav@601:  * later time it will enqueue those newly-cleared weak references that are
jaroslav@601:  * registered with reference queues.
jaroslav@601:  *
jaroslav@601:  * @author   Mark Reinhold
jaroslav@601:  * @since    1.2
jaroslav@601:  */
jaroslav@601: 
jaroslav@601: public class WeakReference<T> extends Reference<T> {
jaroslav@601: 
jaroslav@601:     /**
jaroslav@601:      * Creates a new weak reference that refers to the given object.  The new
jaroslav@601:      * reference is not registered with any queue.
jaroslav@601:      *
jaroslav@601:      * @param referent object the new weak reference will refer to
jaroslav@601:      */
jaroslav@601:     public WeakReference(T referent) {
jaroslav@601:         super(referent);
jaroslav@601:     }
jaroslav@601: 
jaroslav@601:     /**
jaroslav@601:      * Creates a new weak reference that refers to the given object and is
jaroslav@601:      * registered with the given queue.
jaroslav@601:      *
jaroslav@601:      * @param referent object the new weak reference will refer to
jaroslav@601:      * @param q the queue with which the reference is to be registered,
jaroslav@601:      *          or <tt>null</tt> if registration is not required
jaroslav@601:      */
jaroslav@601:     public WeakReference(T referent, ReferenceQueue<? super T> q) {
jaroslav@601:         super(referent, q);
jaroslav@601:     }
jaroslav@601: 
jaroslav@601: }