ojluni/src/main/java/java/beans/PropertyChangeListenerProxy.java

/*
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 * 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
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package java.beans;

import java.util.EventListenerProxy;

/**
 * A class which extends the {@code EventListenerProxy}
 * specifically for adding a {@code PropertyChangeListener}
 * with a "bound" property.
 * Instances of this class can be added
 * as {@code PropertyChangeListener}s to a bean
 * which supports firing property change events.
 * <p>
 * If the object has a {@code getPropertyChangeListeners} method
 * then the array returned could be a mixture of {@code PropertyChangeListener}
 * and {@code PropertyChangeListenerProxy} objects.
 *
 * @see java.util.EventListenerProxy
 * @see PropertyChangeSupport#getPropertyChangeListeners
 * @since 1.4
 */
public class PropertyChangeListenerProxy
        extends EventListenerProxy<PropertyChangeListener>
        implements PropertyChangeListener {

    private final String propertyName;

    /**
     * Constructor which binds the {@code PropertyChangeListener}
     * to a specific property.
     *
     * @param propertyName  the name of the property to listen on
     * @param listener      the listener object
     */
    public PropertyChangeListenerProxy(String propertyName, PropertyChangeListener listener) {
        super(listener);
        this.propertyName = propertyName;
    }

    /**
     * Forwards the property change event to the listener delegate.
     *
     * @param event  the property change event
     */
    public void propertyChange(PropertyChangeEvent event) {
        getListener().propertyChange(event);
    }

    /**
     * Returns the name of the named property associated with the listener.
     *
     * @return the name of the named property associated with the listener
     */
    public String getPropertyName() {
        return this.propertyName;
    }
}