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