1 /*
2 * Copyright (c) 1997, 2004, 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<sup><font size="-2">TM</font></sup>
41 * has been added to the <code>java.beans</code> package.
42 * Please see {@link java.beans.XMLEncoder}.
43 *
44 * @author Dave Moore
45 */
46 public class DefaultSingleSelectionModel implements SingleSelectionModel,
47 Serializable {
48 /* Only one ModelChangeEvent is needed per model instance since the
49 * event's only (read-only) state is the source property. The source
50 * of events generated here is always "this".
51 */
52 protected transient ChangeEvent changeEvent = null;
53 /** The collection of registered listeners */
54 protected EventListenerList listenerList = new EventListenerList();
55
56 private int index = -1;
57
58 // implements javax.swing.SingleSelectionModel
59 public int getSelectedIndex() {
60 return index;
61 }
62
63 // implements javax.swing.SingleSelectionModel
64 public void setSelectedIndex(int index) {
65 if (this.index != index) {
66 this.index = index;
67 fireStateChanged();
68 }
69 }
70
71 // implements javax.swing.SingleSelectionModel
72 public void clearSelection() {
73 setSelectedIndex(-1);
74 }
75
76 // implements javax.swing.SingleSelectionModel
77 public boolean isSelected() {
78 boolean ret = false;
79 if (getSelectedIndex() != -1) {
80 ret = true;
81 }
82 return ret;
83 }
84
85 /**
86 * Adds a <code>ChangeListener</code> to the button.
87 */
88 public void addChangeListener(ChangeListener l) {
89 listenerList.add(ChangeListener.class, l);
90 }
91
92 /**
93 * Removes a <code>ChangeListener</code> from the button.
94 */
95 public void removeChangeListener(ChangeListener l) {
96 listenerList.remove(ChangeListener.class, l);
97 }
98
99 /**
100 * Returns an array of all the change listeners
101 * registered on this <code>DefaultSingleSelectionModel</code>.
102 *
103 * @return all of this model's <code>ChangeListener</code>s
104 * or an empty
105 * array if no change listeners are currently registered
106 *
107 * @see #addChangeListener
108 * @see #removeChangeListener
109 *
110 * @since 1.4
111 */
112 public ChangeListener[] getChangeListeners() {
113 return listenerList.getListeners(ChangeListener.class);
114 }
115
116 /**
117 * Notifies all listeners that have registered interest for
118 * notification on this event type. The event instance
119 * is created lazily.
120 * @see EventListenerList
121 */
122 protected void fireStateChanged() {
123 // Guaranteed to return a non-null array
124 Object[] listeners = listenerList.getListenerList();
125 // Process the listeners last to first, notifying
126 // those that are interested in this event
127 for (int i = listeners.length-2; i>=0; i-=2) {
128 if (listeners[i]==ChangeListener.class) {
129 // Lazily create the event:
130 if (changeEvent == null)
131 changeEvent = new ChangeEvent(this);
132 ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);
133 }
134 }
135 }
136
137 /**
138 * Returns an array of all the objects currently registered as
139 * <code><em>Foo</em>Listener</code>s
140 * upon this model.
141 * <code><em>Foo</em>Listener</code>s
142 * are registered using the <code>add<em>Foo</em>Listener</code> method.
143 * <p>
144 * You can specify the <code>listenerType</code> argument
145 * with a class literal, such as <code><em>Foo</em>Listener.class</code>.
146 * For example, you can query a <code>DefaultSingleSelectionModel</code>
147 * instance <code>m</code>
148 * for its change listeners
149 * with the following code:
150 *
151 * <pre>ChangeListener[] cls = (ChangeListener[])(m.getListeners(ChangeListener.class));</pre>
152 *
153 * If no such listeners exist,
154 * this method returns an empty array.
155 *
156 * @param listenerType the type of listeners requested;
157 * this parameter should specify an interface
158 * that descends from <code>java.util.EventListener</code>
159 * @return an array of all objects registered as
160 * <code><em>Foo</em>Listener</code>s
161 * on this model,
162 * or an empty array if no such
163 * listeners have been added
164 * @exception ClassCastException if <code>listenerType</code> doesn't
165 * specify a class or interface that implements
166 * <code>java.util.EventListener</code>
167 *
168 * @see #getChangeListeners
169 *
170 * @since 1.3
171 */
172 public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
173 return listenerList.getListeners(listenerType);
174 }
175 }