1/*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package javax.swing;
27
28import javax.swing.event.*;
29import java.io.Serializable;
30import java.util.EventListener;
31
32/**
33 * A generic implementation of SingleSelectionModel.
34 * <p>
35 * <strong>Warning:</strong>
36 * Serialized objects of this class will not be compatible with
37 * future Swing releases. The current serialization support is
38 * appropriate for short term storage or RMI between applications running
39 * the same version of Swing.  As of 1.4, support for long term storage
40 * of all JavaBeans&trade;
41 * has been added to the <code>java.beans</code> package.
42 * Please see {@link java.beans.XMLEncoder}.
43 *
44 * @author Dave Moore
45 * @since 1.2
46 */
47@SuppressWarnings("serial") // Same-version serialization only
48public class DefaultSingleSelectionModel implements SingleSelectionModel,
49Serializable {
50    /**
51     * Only one ModelChangeEvent is needed per model instance since the
52     * event's only (read-only) state is the source property.  The source
53     * of events generated here is always "this".
54     */
55    protected transient ChangeEvent changeEvent = null;
56    /** The collection of registered listeners */
57    protected EventListenerList listenerList = new EventListenerList();
58
59    private int index = -1;
60
61    /**
62     * {@inheritDoc}
63     */
64    public int getSelectedIndex() {
65        return index;
66    }
67
68    /**
69     * {@inheritDoc}
70     */
71    public void setSelectedIndex(int index) {
72        if (this.index != index) {
73            this.index = index;
74            fireStateChanged();
75        }
76    }
77
78    /**
79     * {@inheritDoc}
80     */
81    public void clearSelection() {
82        setSelectedIndex(-1);
83    }
84
85    /**
86     * {@inheritDoc}
87     */
88    public boolean isSelected() {
89        boolean ret = false;
90        if (getSelectedIndex() != -1) {
91            ret = true;
92        }
93        return ret;
94    }
95
96    /**
97     * Adds a <code>ChangeListener</code> to the button.
98     */
99    public void addChangeListener(ChangeListener l) {
100        listenerList.add(ChangeListener.class, l);
101    }
102
103    /**
104     * Removes a <code>ChangeListener</code> from the button.
105     */
106    public void removeChangeListener(ChangeListener l) {
107        listenerList.remove(ChangeListener.class, l);
108    }
109
110    /**
111     * Returns an array of all the change listeners
112     * registered on this <code>DefaultSingleSelectionModel</code>.
113     *
114     * @return all of this model's <code>ChangeListener</code>s
115     *         or an empty
116     *         array if no change listeners are currently registered
117     *
118     * @see #addChangeListener
119     * @see #removeChangeListener
120     *
121     * @since 1.4
122     */
123    public ChangeListener[] getChangeListeners() {
124        return listenerList.getListeners(ChangeListener.class);
125    }
126
127    /**
128     * Notifies all listeners that have registered interest for
129     * notification on this event type.  The event instance
130     * is created lazily.
131     * @see EventListenerList
132     */
133    protected void fireStateChanged() {
134        // Guaranteed to return a non-null array
135        Object[] listeners = listenerList.getListenerList();
136        // Process the listeners last to first, notifying
137        // those that are interested in this event
138        for (int i = listeners.length-2; i>=0; i-=2) {
139            if (listeners[i]==ChangeListener.class) {
140                // Lazily create the event:
141                if (changeEvent == null)
142                    changeEvent = new ChangeEvent(this);
143                ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);
144            }
145        }
146    }
147
148    /**
149     * Returns an array of all the objects currently registered as
150     * <code><em>Foo</em>Listener</code>s
151     * upon this model.
152     * <code><em>Foo</em>Listener</code>s
153     * are registered using the <code>add<em>Foo</em>Listener</code> method.
154     * <p>
155     * You can specify the <code>listenerType</code> argument
156     * with a class literal, such as <code><em>Foo</em>Listener.class</code>.
157     * For example, you can query a <code>DefaultSingleSelectionModel</code>
158     * instance <code>m</code>
159     * for its change listeners
160     * with the following code:
161     *
162     * <pre>ChangeListener[] cls = (ChangeListener[])(m.getListeners(ChangeListener.class));</pre>
163     *
164     * If no such listeners exist,
165     * this method returns an empty array.
166     *
167     * @param <T>  the type of {@code EventListener} class being requested
168     * @param listenerType  the type of listeners requested;
169     *          this parameter should specify an interface
170     *          that descends from <code>java.util.EventListener</code>
171     * @return an array of all objects registered as
172     *          <code><em>Foo</em>Listener</code>s
173     *          on this model,
174     *          or an empty array if no such
175     *          listeners have been added
176     * @exception ClassCastException if <code>listenerType</code> doesn't
177     *          specify a class or interface that implements
178     *          <code>java.util.EventListener</code>
179     *
180     * @see #getChangeListeners
181     *
182     * @since 1.3
183     */
184    public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
185        return listenerList.getListeners(listenerType);
186    }
187}
188