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 javafx.beans;
  27 
  28 import java.lang.ref.WeakReference;
  29 import javafx.beans.NamedArg;
  30 
  31 /**
  32  * A {@code WeakInvalidationListener} can be used, if an {@link Observable}
  33  * should only maintain a weak reference to the listener. This helps to avoid
  34  * memory leaks, that can occur if observers are not unregistered from observed
  35  * objects after use.
  36  * <p>
  37  * {@code WeakInvalidationListener} are created by passing in the original
  38  * {@link InvalidationListener}. The {@code WeakInvalidationListener} should
  39  * then be registered to listen for changes of the observed object.
  40  * <p>
  41  * Note: You have to keep a reference to the {@code InvalidationListener}, that
  42  * was passed in as long as it is in use, otherwise it will be garbage collected
  43  * to soon.
  44  *
  45  * @see InvalidationListener
  46  * @see Observable
  47  *
  48  *
  49  * @since JavaFX 2.0
  50  */
  51 public final class WeakInvalidationListener implements InvalidationListener, WeakListener {
  52 
  53     private final WeakReference<InvalidationListener> ref;
  54 
  55     /**
  56      * The constructor of {@code WeakInvalidationListener}.
  57      *
  58      * @param listener
  59      *            The original listener that should be notified
  60      */
  61     public WeakInvalidationListener(@NamedArg("listener") InvalidationListener listener) {
  62         if (listener == null) {
  63             throw new NullPointerException("Listener must be specified.");

  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 javafx.beans;
  27 
  28 import java.lang.ref.WeakReference;
  29 import javafx.beans.NamedArg;
  30 
  31 /**
  32  * A {@code WeakInvalidationListener} can be used if an {@link Observable}
  33  * should only maintain a weak reference to the listener. This helps to avoid
  34  * memory leaks that can occur if observers are not unregistered from observed
  35  * objects after use.
  36  * <p>
  37  * A {@code WeakInvalidationListener} is created by passing in the original
  38  * {@link InvalidationListener}. The {@code WeakInvalidationListener} should
  39  * then be registered to listen for changes of the observed object.
  40  * <p>
  41  * Note: You have to keep a reference to the {@code InvalidationListener} that
  42  * was passed in as long as it is in use, otherwise it can be garbage collected
  43  * too soon.
  44  *
  45  * @see InvalidationListener
  46  * @see Observable
  47  *
  48  *
  49  * @since JavaFX 2.0
  50  */
  51 public final class WeakInvalidationListener implements InvalidationListener, WeakListener {
  52 
  53     private final WeakReference<InvalidationListener> ref;
  54 
  55     /**
  56      * The constructor of {@code WeakInvalidationListener}.
  57      *
  58      * @param listener
  59      *            The original listener that should be notified
  60      */
  61     public WeakInvalidationListener(@NamedArg("listener") InvalidationListener listener) {
  62         if (listener == null) {
  63             throw new NullPointerException("Listener must be specified.");