/* * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * 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. * * This code is distributed in the hope that it will be useful, but WITHOUT * 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). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.swing; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.io.*; import java.lang.ref.WeakReference; import java.lang.ref.ReferenceQueue; /** * A package-private PropertyChangeListener which listens for * property changes on an Action and updates the properties * of an ActionEvent source. *
* Subclasses must override the actionPropertyChanged method, * which is invoked from the propertyChange method as long as * the target is still valid. *
*
* WARNING WARNING WARNING WARNING WARNING WARNING:
* Do NOT create an annonymous inner class that extends this! If you do
* a strong reference will be held to the containing class, which in most
* cases defeats the purpose of this class.
*
* @param T the type of JComponent the underlying Action is attached to
*
* @author Georges Saab
* @see AbstractButton
*/
abstract class ActionPropertyChangeListenerPropertyChangeListener
from the Action,
* otherwise this will invoke actionPropertyChanged.
*/
public final void propertyChange(PropertyChangeEvent e) {
T target = getTarget();
if (target == null) {
getAction().removePropertyChangeListener(this);
} else {
actionPropertyChanged(target, getAction(), e);
}
}
/**
* Invoked when a property changes on the Action and the target
* still exists.
*/
protected abstract void actionPropertyChanged(T target, Action action,
PropertyChangeEvent e);
private void setTarget(T c) {
ReferenceQueue