Java example source code file (DefaultColorSelectionModel.java)

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Java - Java tags/keywords

awt, changeevent, changelistener, color, defaultcolorselectionmodel, event, eventlistenerlist, gui, object, serializable, swing

The DefaultColorSelectionModel.java Java example source code

/*
 * Copyright (c) 1998, 2001, 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.colorchooser;

import javax.swing.*;
import javax.swing.event.*;
import java.awt.Color;
import java.io.Serializable;

/**
 * A generic implementation of <code>ColorSelectionModel.
 *
 * @author Steve Wilson
 *
 * @see java.awt.Color
 */
public class DefaultColorSelectionModel implements ColorSelectionModel, Serializable {

    /**
     * Only one <code>ChangeEvent is needed per model instance
     * since the event's only (read-only) state is the source property.
     * The source of events generated here is always "this".
     */
    protected transient ChangeEvent changeEvent = null;

    protected EventListenerList listenerList = new EventListenerList();

    private Color selectedColor;

    /**
     * Creates a <code>DefaultColorSelectionModel with the
     * current color set to <code>Color.white.  This is
     * the default constructor.
     */
    public DefaultColorSelectionModel() {
        selectedColor = Color.white;
    }

    /**
     * Creates a <code>DefaultColorSelectionModel with the
     * current color set to <code>color, which should be
     * non-<code>null.  Note that setting the color to
     * <code>null is undefined and may have unpredictable
     * results.
     *
     * @param color the new <code>Color
     */
    public DefaultColorSelectionModel(Color color) {
        selectedColor = color;
    }

    /**
     * Returns the selected <code>Color which should be
     * non-<code>null.
     *
     * @return the selected <code>Color
     */
    public Color getSelectedColor() {
        return selectedColor;
    }

    /**
     * Sets the selected color to <code>color.
     * Note that setting the color to <code>null
     * is undefined and may have unpredictable results.
     * This method fires a state changed event if it sets the
     * current color to a new non-<code>null color;
     * if the new color is the same as the current color,
     * no event is fired.
     *
     * @param color the new <code>Color
     */
    public void setSelectedColor(Color color) {
        if (color != null && !selectedColor.equals(color)) {
            selectedColor = color;
            fireStateChanged();
        }
    }


    /**
     * Adds a <code>ChangeListener to the model.
     *
     * @param l the <code>ChangeListener to be added
     */
    public void addChangeListener(ChangeListener l) {
        listenerList.add(ChangeListener.class, l);
    }

    /**
     * Removes a <code>ChangeListener from the model.
     * @param l the <code>ChangeListener to be removed
     */
    public void removeChangeListener(ChangeListener l) {
        listenerList.remove(ChangeListener.class, l);
    }

    /**
     * Returns an array of all the <code>ChangeListeners added
     * to this <code>DefaultColorSelectionModel with
     * <code>addChangeListener.
     *
     * @return all of the <code>ChangeListeners added, or an empty
     *         array if no listeners have been added
     * @since 1.4
     */
    public ChangeListener[] getChangeListeners() {
        return listenerList.getListeners(ChangeListener.class);
    }

    /**
     * Runs each <code>ChangeListener's
     * <code>stateChanged method.
     *
     * <!-- @see #setRangeProperties    //bad link-->
     * @see EventListenerList
     */
    protected void fireStateChanged()
    {
        Object[] listeners = listenerList.getListenerList();
        for (int i = listeners.length - 2; i >= 0; i -=2 ) {
            if (listeners[i] == ChangeListener.class) {
                if (changeEvent == null) {
                    changeEvent = new ChangeEvent(this);
                }
                ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);
            }
        }
    }

}