13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.ref;
27
28
29 /**
30 * Weak reference objects, which do not prevent their referents from being
31 * made finalizable, finalized, and then reclaimed. Weak references are most
32 * often used to implement canonicalizing mappings.
33 *
34 * <p> Suppose that the garbage collector determines at a certain point in time
35 * that an object is <a href="package-summary.html#reachability">weakly
36 * reachable</a>. At that time it will atomically clear all weak references to
37 * that object and all weak references to any other weakly-reachable objects
38 * from which that object is reachable through a chain of strong and soft
39 * references. At the same time it will declare all of the formerly
40 * weakly-reachable objects to be finalizable. At the same time or at some
41 * later time it will enqueue those newly-cleared weak references that are
42 * registered with reference queues.
43 *
44 * @author Mark Reinhold
45 * @since 1.2
46 */
47
48 public non-sealed class WeakReference<T> extends Reference<T> {
49
50 /**
51 * Creates a new weak reference that refers to the given object. The new
52 * reference is not registered with any queue.
53 *
54 * @param referent object the new weak reference will refer to
55 */
56 public WeakReference(T referent) {
57 super(referent);
58 }
59
60 /**
61 * Creates a new weak reference that refers to the given object and is
62 * registered with the given queue.
63 *
64 * @param referent object the new weak reference will refer to
65 * @param q the queue with which the reference is to be registered,
66 * or {@code null} if registration is not required
67 */
68 public WeakReference(T referent, ReferenceQueue<? super T> q) {
69 super(referent, q);
70 }
71
72 }
|
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.ref;
27
28
29 /**
30 * Weak reference objects, which do not prevent their referents from being
31 * made finalizable, finalized, and then reclaimed. Weak references are most
32 * often used to implement canonicalizing mappings.
33 * <p>
34 * The referent must not be an instance of a {@linkplain Class#isValue()
35 * value class}; such a value can never have another reference to it
36 * and cannot be held in a reference type.
37 *
38 * <p> Suppose that the garbage collector determines at a certain point in time
39 * that an object is <a href="package-summary.html#reachability">weakly
40 * reachable</a>. At that time it will atomically clear all weak references to
41 * that object and all weak references to any other weakly-reachable objects
42 * from which that object is reachable through a chain of strong and soft
43 * references. At the same time it will declare all of the formerly
44 * weakly-reachable objects to be finalizable. At the same time or at some
45 * later time it will enqueue those newly-cleared weak references that are
46 * registered with reference queues.
47 *
48 * @author Mark Reinhold
49 * @since 1.2
50 */
51
52 public non-sealed class WeakReference<T> extends Reference<T> {
53
54 /**
55 * Creates a new weak reference that refers to the given object. The new
56 * reference is not registered with any queue.
57 *
58 * @param referent object the new weak reference will refer to
59 * @throws IllegalArgumentException if the referent is an instance of a
60 * {@link Class#isValue() value class}
61 */
62 public WeakReference(T referent) {
63 super(referent);
64 }
65
66 /**
67 * Creates a new weak reference that refers to the given object and is
68 * registered with the given queue.
69 *
70 * @param referent object the new weak reference will refer to
71 * @param q the queue with which the reference is to be registered,
72 * or {@code null} if registration is not required
73 * @throws IllegalArgumentException if the referent is an instance of a
74 * {@link Class#isValue() value class}
75 */
76 public WeakReference(T referent, ReferenceQueue<? super T> q) {
77 super(referent, q);
78 }
79
80 }
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