KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > java > lang > ref > WeakReference


1 /*
2  * @(#)WeakReference.java 1.18 03/12/19
3  *
4  * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5  * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6  */
7
8 package java.lang.ref;
9
10
11 /**
12  * Weak reference objects, which do not prevent their referents from being
13  * made finalizable, finalized, and then reclaimed. Weak references are most
14  * often used to implement canonicalizing mappings.
15  *
16  * <p> Suppose that the garbage collector determines at a certain point in time
17  * that an object is <a HREF="package-summary.html#reachability">weakly
18  * reachable</a>. At that time it will atomically clear all weak references to
19  * that object and all weak references to any other weakly-reachable objects
20  * from which that object is reachable through a chain of strong and soft
21  * references. At the same time it will declare all of the formerly
22  * weakly-reachable objects to be finalizable. At the same time or at some
23  * later time it will enqueue those newly-cleared weak references that are
24  * registered with reference queues.
25  *
26  * @version 1.18, 12/19/03
27  * @author Mark Reinhold
28  * @since 1.2
29  */
30
31 public class WeakReference<T> extends Reference JavaDoc<T> {
32
33     /**
34      * Creates a new weak reference that refers to the given object. The new
35      * reference is not registered with any queue.
36      *
37      * @param referent object the new weak reference will refer to
38      */
39     public WeakReference(T referent) {
40     super(referent);
41     }
42
43     /**
44      * Creates a new weak reference that refers to the given object and is
45      * registered with the given queue.
46      *
47      * @param referent object the new weak reference will refer to
48      * @param q the queue with which the reference is to be registered,
49      * or <tt>null</tt> if registration is not required
50      */
51     public WeakReference(T referent, ReferenceQueue JavaDoc<? super T> q) {
52     super(referent, q);
53     }
54
55 }
56
Popular Tags