com.sun.javafx.beans.event.AbstractNotifyListener Maven / Gradle / Ivy
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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*/
package com.sun.javafx.beans.event;
import javafx.beans.InvalidationListener;
import javafx.beans.WeakInvalidationListener;
/**
* A helper base class for notify listeners. It holds reference to its
* {@code WeakListener} wrapper.
*
* Without this class, an observer which uses weak listeners would need to hold
* two references. The first to the original {@code ChangeListener} to prevent
* it from being garbage collected. The second to the {@code WeakListener}
* wrapper so it can unregister once registered listener. The second reference
* is eliminated by using this class.
*
* Example:
public class Observer {
private AbstractNotifyListener listener = new AbstractNotifyListener() {
public void handle(Bean bean, PropertyReference property) {
// do something
}
};
public void start() {
subject.addChangeListener(property, listener.getWeakListener());
}
public void stop() {
subject.removeChangeListener(property, listener.getWeakListener());
}
}
*/
public abstract class AbstractNotifyListener implements InvalidationListener {
private final WeakInvalidationListener weakListener = new WeakInvalidationListener(this);
public InvalidationListener getWeakListener() {
return weakListener;
}
}