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package javax.swing.colorchooser;

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

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

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

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

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

    
Sets the selected color to color.
Note that setting the color to 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-null color;
if the new color is the same as the current color,
no event is fired.
Params:
color – the new Color/**
     * Sets the selected color to <code>color</code>.
     * Note that setting the color to <code>null</code>
     * 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</code> color;
     * if the new color is the same as the current color,
     * no event is fired.
     *
     * @param color the new <code>Color</code>
     */
    public void setSelectedColor(Color color) {
        if (color != null && !selectedColor.equals(color)) {
            selectedColor = color;
            fireStateChanged();
        }
    }


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

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

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

    
Runs each ChangeListener's
stateChanged method.

See Also:
EventListenerList/**
     * Runs each <code>ChangeListener</code>'s
     * <code>stateChanged</code> 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);
            }
        }
    }

}