/*
* $Id$
*
* Copyright 2004 Sun Microsystems, Inc., 4150 Network Circle,
* Santa Clara, California 95054, U.S.A. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.jdesktop.swingx.action;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.lang.ref.WeakReference;
import javax.swing.AbstractAction;
import javax.swing.AbstractButton;
import javax.swing.Action;
/**
* Added to the Toggle type buttons and menu items so that various components
* which have been created from a single StateChangeAction can be in synch.
*
* This listener is responsible for updating the selected property from the
* Action to the AbstractButton. <p>
*
* It guarantees a maximum of 1 instance of
* ToggleActionPCL to be installed per button (PENDING JW: add test to verify).
* It removes all ToggleActionPCLs which are targeted to unreachable buttons
* from the action's listener list.
*
*
*/
class ToggleActionPropertyChangeListener implements PropertyChangeListener {
private WeakReference<AbstractButton> buttonRef;
public ToggleActionPropertyChangeListener(Action action, AbstractButton button) {
if (shouldAddListener(action, button)) {
this.buttonRef = new WeakReference<AbstractButton>(button);
action.addPropertyChangeListener(this);
}
}
protected synchronized boolean shouldAddListener(Action action, AbstractButton button) {
releasePCLs(action);
// PENDING JW: revisit - we need a configurator to maintain at most a 1:1 from button to
// action anyway: so a true in isToggling must not happen.
//
return !isToggling(action, button);
// return true;
}
protected boolean isToggling(Action action, AbstractButton button) {
if (!(action instanceof AbstractAction)) return false;
PropertyChangeListener[] listeners = ((AbstractAction)action).getPropertyChangeListeners();
for (int i = listeners.length - 1; i >= 0; i--) {
if (listeners[i] instanceof ToggleActionPropertyChangeListener) {
if (((ToggleActionPropertyChangeListener) listeners[i]).isToggling(button)) return true;
}
}
return false;
}
/**
* Removes all ToggleActionPCLs with unreachable target buttons from the
* Action's PCL-listeners.
*
* @param action to cleanup.
*/
protected void releasePCLs(Action action) {
if (!(action instanceof AbstractAction)) return;
PropertyChangeListener[] listeners = ((AbstractAction)action).getPropertyChangeListeners();
for (int i = listeners.length - 1; i >= 0; i--) {
if (listeners[i] instanceof ToggleActionPropertyChangeListener) {
((ToggleActionPropertyChangeListener) listeners[i]).checkReferent(action);
}
}
}
@Override
public void propertyChange(PropertyChangeEvent evt) {
AbstractButton button = checkReferent((Action) evt.getSource());
if (button == null) return;
String propertyName = evt.getPropertyName();
if (propertyName.equals("selected")) {
Boolean selected = (Boolean)evt.getNewValue();
button.setSelected(selected.booleanValue());
}
}
/**
* Returns the target button to synchronize from the listener.
*
* Side-effects if the target is no longer reachable:
* - the internal reference to target is nulled.
* - if the given action is != null, this listener removes
* itself from the action's listener list.
*
* @param action The action this is listening to.
* @return the target button if it is strongly reachable or null
* if it is no longer strongly reachable.
*/
protected AbstractButton checkReferent(Action action) {
AbstractButton button = null;
if (buttonRef != null) {
button = buttonRef.get();
}
if (button == null) {
if (action != null) {
action.removePropertyChangeListener(this);
}
buttonRef = null;
}
return button;
}
/**
* Check if this is already synchronizing the given AbstractButton.
*
* This may have the side-effect of releasing the weak reference to
* the target button.
*
* @param button must not be null
* @return true if this target button and the given comp are equal
* false otherwise.
* @throws NullPointerException if the button is null.
*/
public boolean isToggling(AbstractButton button) {
// JW: should check identity instead of equality?
return button.equals(checkReferent(null));
}
/**
* Checks if this is synchronizing to the same target button as the
* given listener.
*
* This may have the side-effect of releasing the weak reference to
* the target button.
*
* @param pcl The listener to test, must not be null.
* @return true if the target buttons of the given is equal to this target
* button and the button is strongly reachable, false otherwise.
*/
// public boolean isToggling(ToggleActionPropertyChangeListener pcl) {
// AbstractButton other = pcl.checkReferent(null);
// if (other != null) {
// return isToggling(other);
// }
// return false;
// }
}