| /* PropertyChangeListenerProxy.java -- adds a name to a property listener |
| Copyright (C) 2002, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.beans; |
| |
| import java.util.EventListenerProxy; |
| |
| /** |
| * This class provides an extension to <code>PropertyChangeListener</code> - |
| * associating a name with the listener. This can be used to filter the |
| * changes that one is interested in. |
| * |
| * @author Eric Blake (ebb9@email.byu.edu) |
| * @since 1.4 |
| * @status udpated to 1.4 |
| */ |
| public class PropertyChangeListenerProxy extends EventListenerProxy |
| implements PropertyChangeListener |
| { |
| /** |
| * The name of the property to listen for. Package visible for use by |
| * PropertyChangeSupport. |
| */ |
| final String propertyName; |
| |
| /** |
| * Create a new proxy which filters property change events and only passes |
| * changes to the named property on to the delegate. A null propertyName |
| * or listener does not fail now, but may cause a NullPointerException down |
| * the road. |
| * |
| * @param propertyName the property's name to filter on |
| * @param listener the delegate listener |
| */ |
| public PropertyChangeListenerProxy(String propertyName, |
| PropertyChangeListener listener) |
| { |
| super(listener); |
| this.propertyName = propertyName; |
| } |
| |
| /** |
| * Forwards the event on to the delegate if the property name matches. |
| * |
| * @param event the event to pass on, if it meets the filter |
| * @throws NullPointerException if the delegate this was created with is null |
| */ |
| public void propertyChange(PropertyChangeEvent event) |
| { |
| // Note: Sun does not filter, under the assumption that since |
| // PropertyChangeSupport unwraps proxys, this method should never be |
| // called by normal use of listeners. |
| String name = event == null ? null : event.getPropertyName(); |
| if (name == null ? propertyName == null : name.equals(propertyName)) |
| ((PropertyChangeListener) getListener()).propertyChange(event); |
| } |
| |
| /** |
| * Gets the name of the property this proxy is filtering on. |
| * |
| * @return the property name |
| */ |
| public String getPropertyName() |
| { |
| return propertyName; |
| } |
| } // class PropertyChangeListenerProxy |