/*

 * Copyright (c) 1997, 2015, 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;

import javax.swing.event.*;

import java.io.Serializable;

import java.util.EventListener;

/**

 * A generic implementation of SingleSelectionModel.

 * <p>

 * <strong>Warning:</strong>

 * Serialized objects of this class will not be compatible with

 * future Swing releases. The current serialization support is

 * appropriate for short term storage or RMI between applications running

 * the same version of Swing.  As of 1.4, support for long term storage

 * of all JavaBeans™

 * has been added to the <code>java.beans</code> package.

 * Please see {@link java.beans.XMLEncoder}.

 *

 * @author Dave Moore

 * @since 1.2

 */

@SuppressWarnings("serial") // Same-version serialization only

public class DefaultSingleSelectionModel implements SingleSelectionModel,

Serializable {

    /**

     * Only one ModelChangeEvent 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;

    /** The collection of registered listeners */

    protected EventListenerList listenerList = new EventListenerList();

    private int index = -1;

    /**

     * {@inheritDoc}

     */

    public int getSelectedIndex() {

        return index;

    }

    /**

     * {@inheritDoc}

     */

    public void setSelectedIndex(int index) {

        if (this.index != index) {

            this.index = index;

            fireStateChanged();

        }

    }

    /**

     * {@inheritDoc}

     */

    public void clearSelection() {

        setSelectedIndex(-1);

    }

    /**

     * {@inheritDoc}

     */

    public boolean isSelected() {

        boolean ret = false;

        if (getSelectedIndex() != -1) {

            ret = true;

        }

        return ret;

    }

    /**

     * Adds a <code>ChangeListener</code> to the button.

     */

    public void addChangeListener(ChangeListener l) {

        listenerList.add(ChangeListener.class, l);

    }

    /**

     * Removes a <code>ChangeListener</code> from the button.

     */

    public void removeChangeListener(ChangeListener l) {

        listenerList.remove(ChangeListener.class, l);

    }

    /**

     * Returns an array of all the change listeners

     * registered on this <code>DefaultSingleSelectionModel</code>.

     *

     * @return all of this model's <code>ChangeListener</code>s

     *         or an empty

     *         array if no change listeners are currently registered

     *

     * @see #addChangeListener

     * @see #removeChangeListener

     *

     * @since 1.4

     */

    public ChangeListener[] getChangeListeners() {

        return listenerList.getListeners(ChangeListener.class);

    }

    /**

     * Notifies all listeners that have registered interest for

     * notification on this event type.  The event instance

     * is created lazily.

     * @see EventListenerList

     */

    protected void fireStateChanged() {

        // Guaranteed to return a non-null array

        Object[] listeners = listenerList.getListenerList();

        // Process the listeners last to first, notifying

        // those that are interested in this event

        for (int i = listeners.length-2; i>=0; i-=2) {

            if (listeners[i]==ChangeListener.class) {

                // Lazily create the event:

                if (changeEvent == null)

                    changeEvent = new ChangeEvent(this);

                ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);

            }

        }

    }

    /**

     * Returns an array of all the objects currently registered as

     * <code><em>Foo</em>Listener</code>s

     * upon this model.

     * <code><em>Foo</em>Listener</code>s

     * are registered using the <code>add<em>Foo</em>Listener</code> method.

     * <p>

     * You can specify the <code>listenerType</code> argument

     * with a class literal, such as <code><em>Foo</em>Listener.class</code>.

     * For example, you can query a <code>DefaultSingleSelectionModel</code>

     * instance <code>m</code>

     * for its change listeners

     * with the following code:

     *

     * <pre>ChangeListener[] cls = (ChangeListener[])(m.getListeners(ChangeListener.class));</pre>

     *

     * If no such listeners exist,

     * this method returns an empty array.

     *

     * @param <T>  the type of {@code EventListener} class being requested

     * @param listenerType  the type of listeners requested;

     *          this parameter should specify an interface

     *          that descends from <code>java.util.EventListener</code>

     * @return an array of all objects registered as

     *          <code><em>Foo</em>Listener</code>s

     *          on this model,

     *          or an empty array if no such

     *          listeners have been added

     * @exception ClassCastException if <code>listenerType</code> doesn't

     *          specify a class or interface that implements

     *          <code>java.util.EventListener</code>

     *

     * @see #getChangeListeners

     *

     * @since 1.3

     */

    public <T extends EventListener> T[] getListeners(Class<T> listenerType) {

        return listenerList.getListeners(listenerType);

    }

}