9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * @param <T> the type of the referent
44 *
45 * @author Mark Reinhold
46 * @since 1.2
47 */
48
49 public non-sealed class WeakReference<T> extends Reference<T> {
50
51 /**
52 * Creates a new weak reference that refers to the given object. The new
53 * reference is not registered with any queue.
54 *
55 * @param referent object the new weak reference will refer to
56 */
57 public WeakReference(T referent) {
58 super(referent);
59 }
60
61 /**
62 * Creates a new weak reference that refers to the given object and is
63 * registered with the given queue.
64 *
65 * @param referent object the new weak reference will refer to
66 * @param q the queue with which the reference is to be registered,
67 * or {@code null} if registration is not required
68 */
69 public WeakReference(T referent, ReferenceQueue<? super T> q) {
70 super(referent, q);
71 }
72
73 }
|
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 import java.util.Objects;
30
31 /**
32 * Weak reference objects, which do not prevent their referents from being
33 * made finalizable, finalized, and then reclaimed. Weak references are most
34 * often used to implement canonicalizing mappings.
35 * <p>
36 * The referent must be an {@linkplain Objects#isIdentityObject(Object) identity object}.
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 * @param <T> the type of the referent
48 *
49 * @author Mark Reinhold
50 * @since 1.2
51 */
52
53 public non-sealed class WeakReference<T> extends Reference<T> {
54
55 /**
56 * Creates a new weak reference that refers to the given object. The new
57 * reference is not registered with any queue.
58 *
59 * @param referent object the new weak reference will refer to
60 * @throws IdentityException if the referent is not an
61 * {@link java.util.Objects#isIdentityObject(Object) identity object}
62 */
63 public WeakReference(T referent) {
64 super(referent);
65 }
66
67 /**
68 * Creates a new weak reference that refers to the given object and is
69 * registered with the given queue.
70 *
71 * @param referent object the new weak reference will refer to
72 * @param q the queue with which the reference is to be registered,
73 * or {@code null} if registration is not required
74 * @throws IdentityException if the referent is not an
75 * {@link java.util.Objects#isIdentityObject(Object) identity object}
76 */
77 public WeakReference(T referent, ReferenceQueue<? super T> q) {
78 super(referent, q);
79 }
80
81 }
|