src/java.desktop/share/classes/javax/swing/event/SwingPropertyChangeSupport.java

/*
 * Copyright (c) 1998, 2021, 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
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package javax.swing.event;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeSupport;
import java.io.Serial;

import javax.swing.SwingUtilities;

/**
 * This subclass of {@code java.beans.PropertyChangeSupport} is almost
 * identical in functionality. The only difference is if constructed with
 * {@code SwingPropertyChangeSupport(sourceBean, true)} it ensures
 * listeners are only ever notified on the <i>Event Dispatch Thread</i>.
 *
 * @author Igor Kushnirskiy
 */

public final class SwingPropertyChangeSupport extends PropertyChangeSupport {

    /**
     * Constructs a SwingPropertyChangeSupport object.
     *
     * @param sourceBean  The bean to be given as the source for any
     *        events.
     * @throws NullPointerException if {@code sourceBean} is
     *         {@code null}
     */
    public SwingPropertyChangeSupport(Object sourceBean) {
        this(sourceBean, false);
    }

    /**
     * Constructs a SwingPropertyChangeSupport object.
     *
     * @param sourceBean the bean to be given as the source for any events
     * @param notifyOnEDT whether to notify listeners on the <i>Event
     *        Dispatch Thread</i> only
     *
     * @throws NullPointerException if {@code sourceBean} is
     *         {@code null}
     * @since 1.6
     */
    public SwingPropertyChangeSupport(Object sourceBean, boolean notifyOnEDT) {
        super(sourceBean);
        this.notifyOnEDT = notifyOnEDT;
    }

    /**
     * {@inheritDoc}
     *
     * <p>
     * If {@link #isNotifyOnEDT} is {@code true} and called off the
     * <i>Event Dispatch Thread</i> this implementation uses
     * {@code SwingUtilities.invokeLater} to send out the notification
     * on the <i>Event Dispatch Thread</i>. This ensures  listeners
     * are only ever notified on the <i>Event Dispatch Thread</i>.
     *
     * @throws NullPointerException if {@code evt} is
     *         {@code null}
     * @since 1.6
     */
    public void firePropertyChange(final PropertyChangeEvent evt) {
        if (evt == null) {
            throw new NullPointerException();
        }
        if (! isNotifyOnEDT()
            || SwingUtilities.isEventDispatchThread()) {
            super.firePropertyChange(evt);
        } else {
            SwingUtilities.invokeLater(
                new Runnable() {
                    public void run() {
                        firePropertyChange(evt);
                    }
                });
        }
    }

    /**
     * Returns {@code notifyOnEDT} property.
     *
     * @return {@code notifyOnEDT} property
     * @see #SwingPropertyChangeSupport(Object sourceBean, boolean notifyOnEDT)
     * @since 1.6
     */
    public boolean isNotifyOnEDT() {
        return notifyOnEDT;
    }

    /**
     * Use serialVersionUID from JDK 1.2 for interoperability.
     */
    @Serial
    private static final long serialVersionUID = 7162625831330845068L;

    /**
     * whether to notify listeners on EDT
     *
     * @serial
     * @since 1.6
     */
    private final boolean notifyOnEDT;
}