1 /*
2 * Copyright (c) 1997, 2014, 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
26 package javax.swing;
27
28 import javax.swing.event.*;
29 import java.io.Serializable;
30 import 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™
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
48 public class DefaultSingleSelectionModel implements SingleSelectionModel,
49 Serializable {
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 }