/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

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&trade;
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author Dave Moore
 */
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;

 // implements javax.swing.SingleSelectionModel
 public int getSelectedIndex() {
 return index;
 }

 // implements javax.swing.SingleSelectionModel
 public void setSelectedIndex(int index) {
 if (this.index != index) {
 this.index = index;
 fireStateChanged();
 }
 }

 // implements javax.swing.SingleSelectionModel
 public void clearSelection() {
 setSelectedIndex(-1);
 }

 // implements javax.swing.SingleSelectionModel
 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 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);
 }
}