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 /* Only one ModelChangeEvent is needed per model instance since the
51 * event's only (read-only) state is the source property. The source
52 * of events generated here is always "this".
53 */
54 protected transient ChangeEvent changeEvent = null;
55 /** The collection of registered listeners */
56 protected EventListenerList listenerList = new EventListenerList();
57
58 private int index = -1;
59
60 // implements javax.swing.SingleSelectionModel
61 public int getSelectedIndex() {
62 return index;
63 }
64
65 // implements javax.swing.SingleSelectionModel
66 public void setSelectedIndex(int index) {
67 if (this.index != index) {
68 this.index = index;
69 fireStateChanged();
70 }
71 }
72
73 // implements javax.swing.SingleSelectionModel
74 public void clearSelection() {
75 setSelectedIndex(-1);
76 }
77
78 // implements javax.swing.SingleSelectionModel
79 public boolean isSelected() {
80 boolean ret = false;
81 if (getSelectedIndex() != -1) {
82 ret = true;
83 }
84 return ret;
85 }
86
87 /**
88 * Adds a <code>ChangeListener</code> to the button.
89 */
90 public void addChangeListener(ChangeListener l) {
91 listenerList.add(ChangeListener.class, l);
92 }
93
94 /**
95 * Removes a <code>ChangeListener</code> from the button.
96 */
97 public void removeChangeListener(ChangeListener l) {
98 listenerList.remove(ChangeListener.class, l);
99 }
100
101 /**
102 * Returns an array of all the change listeners
103 * registered on this <code>DefaultSingleSelectionModel</code>.
104 *
105 * @return all of this model's <code>ChangeListener</code>s
106 * or an empty
107 * array if no change listeners are currently registered
108 *
109 * @see #addChangeListener
110 * @see #removeChangeListener
111 *
112 * @since 1.4
113 */
114 public ChangeListener[] getChangeListeners() {
115 return listenerList.getListeners(ChangeListener.class);
116 }
117
118 /**
119 * Notifies all listeners that have registered interest for
120 * notification on this event type. The event instance
121 * is created lazily.
122 * @see EventListenerList
123 */
124 protected void fireStateChanged() {
125 // Guaranteed to return a non-null array
126 Object[] listeners = listenerList.getListenerList();
127 // Process the listeners last to first, notifying
128 // those that are interested in this event
129 for (int i = listeners.length-2; i>=0; i-=2) {
130 if (listeners[i]==ChangeListener.class) {
131 // Lazily create the event:
132 if (changeEvent == null)
133 changeEvent = new ChangeEvent(this);
134 ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);
135 }
136 }
137 }
138
139 /**
140 * Returns an array of all the objects currently registered as
141 * <code><em>Foo</em>Listener</code>s
142 * upon this model.
143 * <code><em>Foo</em>Listener</code>s
144 * are registered using the <code>add<em>Foo</em>Listener</code> method.
145 * <p>
146 * You can specify the <code>listenerType</code> argument
147 * with a class literal, such as <code><em>Foo</em>Listener.class</code>.
148 * For example, you can query a <code>DefaultSingleSelectionModel</code>
149 * instance <code>m</code>
150 * for its change listeners
151 * with the following code:
152 *
153 * <pre>ChangeListener[] cls = (ChangeListener[])(m.getListeners(ChangeListener.class));</pre>
154 *
155 * If no such listeners exist,
156 * this method returns an empty array.
157 *
158 * @param listenerType the type of listeners requested;
159 * this parameter should specify an interface
160 * that descends from <code>java.util.EventListener</code>
161 * @return an array of all objects registered as
162 * <code><em>Foo</em>Listener</code>s
163 * on this model,
164 * or an empty array if no such
165 * listeners have been added
166 * @exception ClassCastException if <code>listenerType</code> doesn't
167 * specify a class or interface that implements
168 * <code>java.util.EventListener</code>
169 *
170 * @see #getChangeListeners
171 *
172 * @since 1.3
173 */
174 public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
175 return listenerList.getListeners(listenerType);
176 }
177 }