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 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 }