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 * The abstract definition for the data model that provides
34 * a <code>List</code> with its contents.
35 * <p>
36 * <strong>Warning:</strong>
37 * Serialized objects of this class will not be compatible with
38 * future Swing releases. The current serialization support is
39 * appropriate for short term storage or RMI between applications running
40 * the same version of Swing. As of 1.4, support for long term storage
41 * of all JavaBeans<sup><font size="-2">TM</font></sup>
42 * has been added to the <code>java.beans</code> package.
43 * Please see {@link java.beans.XMLEncoder}.
44 *
45 * @author Hans Muller
46 */
47 public abstract class AbstractListModel implements ListModel, Serializable
48 {
49 protected EventListenerList listenerList = new EventListenerList();
50
51
52 /**
53 * Adds a listener to the list that's notified each time a change
54 * to the data model occurs.
55 *
56 * @param l the <code>ListDataListener</code> to be added
57 */
58 public void addListDataListener(ListDataListener l) {
59 listenerList.add(ListDataListener.class, l);
60 }
61
62
63 /**
64 * Removes a listener from the list that's notified each time a
65 * change to the data model occurs.
66 *
67 * @param l the <code>ListDataListener</code> to be removed
68 */
69 public void removeListDataListener(ListDataListener l) {
70 listenerList.remove(ListDataListener.class, l);
71 }
72
73
74 /**
75 * Returns an array of all the list data listeners
76 * registered on this <code>AbstractListModel</code>.
77 *
78 * @return all of this model's <code>ListDataListener</code>s,
79 * or an empty array if no list data listeners
80 * are currently registered
81 *
82 * @see #addListDataListener
83 * @see #removeListDataListener
84 *
85 * @since 1.4
86 */
87 public ListDataListener[] getListDataListeners() {
88 return listenerList.getListeners(ListDataListener.class);
89 }
90
91
92 /**
93 * <code>AbstractListModel</code> subclasses must call this method
94 * <b>after</b>
95 * one or more elements of the list change. The changed elements
96 * are specified by the closed interval index0, index1 -- the endpoints
97 * are included. Note that
98 * index0 need not be less than or equal to index1.
99 *
100 * @param source the <code>ListModel</code> that changed, typically "this"
101 * @param index0 one end of the new interval
102 * @param index1 the other end of the new interval
103 * @see EventListenerList
104 * @see DefaultListModel
105 */
106 protected void fireContentsChanged(Object source, int index0, int index1)
107 {
108 Object[] listeners = listenerList.getListenerList();
109 ListDataEvent e = null;
110
111 for (int i = listeners.length - 2; i >= 0; i -= 2) {
112 if (listeners[i] == ListDataListener.class) {
113 if (e == null) {
114 e = new ListDataEvent(source, ListDataEvent.CONTENTS_CHANGED, index0, index1);
115 }
116 ((ListDataListener)listeners[i+1]).contentsChanged(e);
117 }
118 }
119 }
120
121
122 /**
123 * <code>AbstractListModel</code> subclasses must call this method
124 * <b>after</b>
125 * one or more elements are added to the model. The new elements
126 * are specified by a closed interval index0, index1 -- the enpoints
127 * are included. Note that
128 * index0 need not be less than or equal to index1.
129 *
130 * @param source the <code>ListModel</code> that changed, typically "this"
131 * @param index0 one end of the new interval
132 * @param index1 the other end of the new interval
133 * @see EventListenerList
134 * @see DefaultListModel
135 */
136 protected void fireIntervalAdded(Object source, int index0, int index1)
137 {
138 Object[] listeners = listenerList.getListenerList();
139 ListDataEvent e = null;
140
141 for (int i = listeners.length - 2; i >= 0; i -= 2) {
142 if (listeners[i] == ListDataListener.class) {
143 if (e == null) {
144 e = new ListDataEvent(source, ListDataEvent.INTERVAL_ADDED, index0, index1);
145 }
146 ((ListDataListener)listeners[i+1]).intervalAdded(e);
147 }
148 }
149 }
150
151
152 /**
153 * <code>AbstractListModel</code> subclasses must call this method
154 * <b>after</b> one or more elements are removed from the model.
155 * <code>index0</code> and <code>index1</code> are the end points
156 * of the interval that's been removed. Note that <code>index0</code>
157 * need not be less than or equal to <code>index1</code>.
158 *
159 * @param source the <code>ListModel</code> that changed, typically "this"
160 * @param index0 one end of the removed interval,
161 * including <code>index0</code>
162 * @param index1 the other end of the removed interval,
163 * including <code>index1</code>
164 * @see EventListenerList
165 * @see DefaultListModel
166 */
167 protected void fireIntervalRemoved(Object source, int index0, int index1)
168 {
169 Object[] listeners = listenerList.getListenerList();
170 ListDataEvent e = null;
171
172 for (int i = listeners.length - 2; i >= 0; i -= 2) {
173 if (listeners[i] == ListDataListener.class) {
174 if (e == null) {
175 e = new ListDataEvent(source, ListDataEvent.INTERVAL_REMOVED, index0, index1);
176 }
177 ((ListDataListener)listeners[i+1]).intervalRemoved(e);
178 }
179 }
180 }
181
182 /**
183 * Returns an array of all the objects currently registered as
184 * <code><em>Foo</em>Listener</code>s
185 * upon this model.
186 * <code><em>Foo</em>Listener</code>s
187 * are registered using the <code>add<em>Foo</em>Listener</code> method.
188 * <p>
189 * You can specify the <code>listenerType</code> argument
190 * with a class literal, such as <code><em>Foo</em>Listener.class</code>.
191 * For example, you can query a list model
192 * <code>m</code>
193 * for its list data listeners
194 * with the following code:
195 *
196 * <pre>ListDataListener[] ldls = (ListDataListener[])(m.getListeners(ListDataListener.class));</pre>
197 *
198 * If no such listeners exist,
199 * this method returns an empty array.
200 *
201 * @param listenerType the type of listeners requested;
202 * this parameter should specify an interface
203 * that descends from <code>java.util.EventListener</code>
204 * @return an array of all objects registered as
205 * <code><em>Foo</em>Listener</code>s
206 * on this model,
207 * or an empty array if no such
208 * listeners have been added
209 * @exception ClassCastException if <code>listenerType</code> doesn't
210 * specify a class or interface that implements
211 * <code>java.util.EventListener</code>
212 *
213 * @see #getListDataListeners
214 *
215 * @since 1.3
216 */
217 public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
218 return listenerList.getListeners(listenerType);
219 }
220 }